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L ON ION
In collaboralion wilh
Deparlment ot ENT, Lucerne Cantonal Hospital, Switzerland
TEMPORAL BONE DISSECTION - The ZURICH Guidelines -
Prof. Ugo FISCH, M.D. ENT Center, Hirslanden Hospital, Zurich, Switzerland
In collaboration with
Assoc. Prof. Thomas LINDER, M.D. Department of ENT, Lucerne Cantonal Hospital, Switzerland
89 Illustrations by Katja Dalkowski, M.D. Buckenhof, Germany
This booklet is based on teaching material distributed at the yearly held Temporal Bone Dissection Courses organized
by the Fisch International Microsurgery Foundation at the Anatomy Department of the University of Zurich, Switzerland
Chairman: Prof. Peter Groscurth, M.D.
We are grateful to the follow ing persons, who have helped in our courses for more than
15 years and contributed in developing the principles exposed in this booklet:
Prof. John May, M.D. Wake Forest University, Winston Salem NC, USA
Prof. Rodrigo Posada, M.D. University of Pereira Pereira, Colombia
FISCH INTERNATIONAL MICROSURGERY FOUNDATION
•
4
Illustrations by: Katja Dalkow sk i, M.D. Grasweg 42 0-91054 Buckenhof, Germany Email: [email protected]
Please note: Medical knowledge IS aver changmg. As new research and clinical e~perience broaden our knowledge, changes in treatment and drvg therapy may be reqUIred. The auth~ and editors of the material herein have consulted sources believed to be reliable in their efforts to proVide information thaI IS complete and in accordance With the standards accepted at the time of publication. However. in view of the poSSibility of human error by the authors, editorS. or publlshef 01 the work here,n. or changes In medICal knowledge. n<her the authors. editors. publisher, nor any other party who has been inVolved in the preparation 01 thIS work, warrants that the infOfmahon contained herem is 10 every respect accurate or complete. and they are not responSible for any errors or orlllSSIOflS or lor the results obtained from use 01 such InlO4TT1atlon. The onformatoon conlall1ed wlthtn thiS brochure IS Intended fOf use by doctOfS and other heallh care professoonals This matenal IS nol Inleoded fOf use as a baSIS for treatment OeclSoonS. and IS not a substitute fOf professional consul· tatlOO and/Of peer-reviewed medICal hletature. Some of the product names. patents. and reglsteted deslgns referred to 111 thiS booIIlet are In facl registered trademarlls Of proprlelary names even though specific reference 10 thiS fact IS nol always made In lhe text Therefore. the appearance of a name Without deSignation as propnetary IS not to be construed as a representation by the publisher that It is in the public domain .
Temporal Bone Dissection - The Zurich Guidelines
Temporal Bone Dissect ion - The Zurich Guidelines Prof. Ugo FISCH, M.D. ENT Center, Hirslanden Hospital, Zurich. Switzerland In col laboration with Assoc. Prof . Thomas LINDER, M.D. Department of ENT, Lucerne Cantonal Hospital. Switzerland
Contact: Fisch International Microsurgery Foundat ion Forchstr. 26. CH-8703 Erlenbach Switzerland Phone: +41 (0)1 9106828 Fax: +41 (0)1 9106126 Email: [email protected]
C 20Cl6 Endo-Press"'. Tutthngen, Geliliany ISBN 3-89756-106-9. Pnnted In Gem1any P.O. Box, 0-78503 Tutlhngen Phone: +497461114590 Fax.: +497461nOB-529 E-mail: EndopressOt-onhne.de
Editions in other languages than English and German are in preparation. For up-tO-date information. please contact EndoPress"" Tuttlingen. at the address mentioned above.
Typesetting and Image Processing : Endo-Press'" Tuttlingen, 0-78503 Tuttlingen. Germany
Printed by: Straub Druck+Medien AG, 0-78713 Schramberg, Germany
1106·2
All rights reserved. No part of thiS publication may be translated. reprinted or reproduced. transmitted In any form or by any means. electronIC or mechanica l, now known or hereafter invented. including photocopying and recorchng, or utilized in any informatIOn storage or retrieval system without the prior wnUen permission of the copyright hokler.
Temp
Tal
•
Temporal Bone Dissection - The Zurich Guidelines 5
Table of Contents
A.1 Introduction .................. .. . . ........... .. . . . . .... . .. . ... ........ 6
A.2 General Preparation ............. . . . . . ... .. . . . .. ... . .... . . . ....... . .... 6
A.3 Specific Surgical Techniques ...... . .. . . . . .. . . . .. . . .. . . . ...... . . . . .. ... • 7
B Closed-Cavity Technique .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
B.1 Tympano-Antrotomy (Meatoplasty, Canalplasty, Myringoplasty, Antrotomy, Epitympanotomy, Osslculoplasty, Mastoid Drainage) .... . . .... ........ 7
B.1.1 Meatoplasty . . ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 B.1.2 Canalplasty ......................................... . . . . . . . . . . . . g B 1.3 Myringoplasty ............ . . ...... ................ . . . .. . . .. ...... 13 B.1.4 Antrotomy ................. . . .... ................ . . .... ......... 15 B.1.5 Epitympanotomy .............. . . .. .................. . . .. ......... 15 B.1.6 Transmastoid Drainage of the Antrum ............................... 16
B.2 Tympano-Mastoidec tomy
(Meatoplasty, Canalplasty, Epitympanectomy. Mastoidectomy, Posterior Tympanotomy, Ossiculoplasty, Myringoplasty, Mastoid Drainage) B.2.1 Mastoidectomy ............................................. 17 B.2.2 Posterior Tympanotomy ...... ................ ...... .......... 17 B.2.3 Epitympanectomy ........... ............ ...... ...... . . . . .. . . 18
B.3 Myringoplasty and Ossiculoplasty in Closed Cavities B.3.1 Myringoplasty ......... . .......................... . . .. . .•. .. 19 B.3.2 Ossiculoplasty (Incus-Interposition) .................. . .. ...... . 20
C Stapedotomy C.l Incus-Stapedotomy .............................................. 22 C.2 Malleo-Stapedotomy ............ ... ................... ... ......... 28
o Open Cavity Techniques (Mastoido-Epitympanectomy, Open MET) D.1 Mastoidectomy ........ ........ ........................ .... . .. ... 32 D.2 Epitympanotomy ................................................ . 34 0 .3 Completion of Mastoido-Epitympanectomy .......................... 34
E Tympanoplasty (Myringoplasty and Ossiculoplasty) in Open Cavities .........• 35 E.l Type III Tympanoplasty ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • 35 E.2 Total Reconstruction of the Ossicular Chain .......................... 36 E.2. l Fisch Titanium Total Prosthesis .......................... . . . . . . . . . . . 36 E.2.2 Titanium Neo-Malleus . . . . . . . . . . . . . . . . . . . . . . . . • . . . . • . . . . • . . . . . . . . . . 41
F Additional Temporal Bone Dissections F.l Subtotal Petrosectomy .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 F.l.1 Subtotal Petrosectomy with Preservation of the Otic Capsule ........ ... 42 F.l.2 Subtotal Petrosectomy with Removal of the Otic Capsule .... . . . . . . . . . . . 43
G Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
H Prostheses and Instruments
H.l FISCH Titanium Middle Ear Prostheses. . . . . . . . . . . . . • . . . . . . . . . . • . . . • . . 45 H.2 FISCH Special Instruments for Tympanoplasty,
Mastoidectomy and Stapedotomy . . . . . . . . . . . . . . . . . • . . . . • . . . . . . . . . . . . 45
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6
A.1 Introduction The series of surgical techniques described in this article relates to procedures that can be practiced in a course using two temporal bones. The first bone is used to demonstrate the closed-cavity tympano-mastoidectomy with related myringoplasty and ossiculoplasty (incus interpoSition). The second bone is used to demonstrate stapes surgery ~ncus-stapedotomy and malleo-stapedotomy) and open-cavity mastoido-epitympanectomy.
The surgical steps described in these guidelines require special instrumentation. The most important instruments are mentioned in the text, highlighted in italics. For more details on Prostheses and Instrumentation see Section H.
More information concerning the described surgical procedures is given in Section G (Suggested Reading),
ArtICular tube«:le
CD Temporal line
<i) Spine of Henle
@ Tympar.ornastold suture
M. sternocleidomastoideus
Temporal Bone Dissection - The Zurich Guidelines
A.2 General Preparation The temporal bone should be placed in the normal operat ing position, with the posterior aspect toward the surgeon and the temporomandibular joint away from the surgeon.
Remove excess bone from the temporal squama using a cutting burr to ensure that the remaining temporal bone fits within the holder, permitting complete rotation in the anlero-posterior plane.
Initially, the external ear is left attached to the temporal bone to enable the meatoplasty technique to be performed within closed cavities. Following meatoplasty (or when the pinna is not available), the external canal is transected 2 em lateral to the bone-cartilaginous junction. All excess soft tissue that is not used during the dissection is removed from the bone.
Identify the following anatomical landmarks (Fig. 1):
CD Temporal line ® Tympanomastoid suture
<i) Spine of Henle ® Tympanosquarnous suture
@ Mastoid tiP ® Petrotympanic fissure
Zygomatic process
, I
Petrotympanic fissure
Styloid pmcess
TympaniC booe
Mastoid process
--@Mastold tip
M. dlgastncus
M. longus capi tis
1 M. spleniUS capitis
•
Tomp
A.3
Be
B.l
The!
Meat. Antro
B.l .
GenE
Meat. when oa"~ (Fig. , edto sis ar ment exter sel f-c canal
The I c"'" b" A-•
Skin
The t positl enda to thl tory (
The , throo EAC
A thi CISIOI
(Fig.
Elev,
Theb SCISS! culan meot
Temporal Bone Dissection - The Zurich Guidelines
A.3 Specific Surgical Techniques
B Closed-Cavity Technique
B.1 Tympano-Antrotomy
The steps of this operation are:
Meatoplasty, Canalplasty, Ossiculoplasty, Mynngoplasty, Antratomy, Epitympanotomy and Mastoid Drainage,
B.1.1 Meatoplasty
General Considerations
Meatoplasty is a necessary step in addition to canalplasty when the cartilaginous portion of the external auditory canal (EAC) is too narrow in relation to its osseous portion (Fig. 2 a, C), Lateral stenosIs of the EAC is commonly related to congenital anomalies, minor malformations, exostosis and postsurgical scarring. It may lead to hearing impairment, excessive accumulation of cerumen, chronic otitis externa, difficulties in clinical examination and insufficient self-cleansing properties of the external ear following canalplasty.
The principle of meatoplasty is to remove the obstruction created by excessive conchal cartilage and bone (Figs. 2 a, b; A-B). The operation is performed with a microscope,
Skin Incision
The first superior skin incision begins at the 12 o'clock position between the tragus and helix, as is the case of an endaural approach (Fig, 3, A-B-C), and is cont inued down to the level of the superior edge of the bony external auditory canal.
The second incision is made at 6 o'clock and cont inues through the ring of cartilage forming the inferior edge of the EAC (Fig. 3, O-E).
A third, medial skin incision connects both previous incisions horizontally along the posterior edge of the EAC (Fig. 3, C-D).
Elevation of the Laterally Based Skin Flap
The laterally based skin flap IS elevated using tympanoplasty scissors. Care must be taken to keep the skin intact, parti-
2.
3
cularly when separating it from the thin but strong attach- A ment to the conchal cartilage (Fig. 4).
4
. ,,' . • '-'II. " , .' , ." ,
c
Endaural Retractor
7
' E
8
Bony external canal
5.
B
•
•
7
8
Skin flap
F
Conchal cartilage
E
Relieving inciSion
E
Temporal Bone Dissection - The Zurich Guidelines
Excess of bone behind external auditOf)' canal
5. Edge of excised conchal cartilage
Exposure and Excision of Conchal Cartilage
Excess conchal cartilage is exposed (Fig . 5 a) and excised (Fig. 5 b). and the soft tissues situated between the excised cartilage and the underlying bone are also removed.
Enlargement of the Bony EAC
The posterior wall of the bony EAC is enlarged using a diamond burr (Fig. 6).
Wound Closure
Before closing the wound, a rel ieving Incision is made through the inferior part of the laterally based meatal skin flap (Fig. 7, F) to allow superior rotation of its upper part (Fig. 8, C, 0). In this way, the enlarged superior external auditory meatus is completely covered with skin. which is kept in position with 4-0 Ethibond sutures (Fig. 9), The inferior enlarged portion of the EAC is left open and will heal by secondary intention within 2-3 weeks.
NOTE: A meatoplasty can be performed on the temporal bone only if the pinna has been preserved. Pertorming a meatoplasty will not allow the surgeon to carry out the first steps of the retroauricular approach described under B 1.2.
9
,
6 .1.
Gent
The shou exler annu
Peril
The with size is al (Fig.
Exp<
The "pe the , open (Fig. tissu lory.
Temporal Bone Dissection - The Zurich Guidelines
Aetroauricular
'0
B.1.2 Canalplasty
General Considerations
The goal of any tympanomastoid surgical procedure should be the circumferenttal enlargement of the bony extemal canal to visualize the entire ring of the tympanic annulus using one position of the microscope (Fig. 10).
Periosteal Flap
The outline of the relroauricular periosteal flap is formed with a knife (No. 15 blade) and should be approximately the size of the index finger (Fig. 11 , A). The periosteal flap is elevated from the bone with a mastoid raspatory (Fig. 11, B).
Exposure of the EAC
The posterior limb of the canal incision (Fig. 12, A-B) is pertormed with a No. 15 blade, maintaining a level below the entrance of the bony external canal. The EAC is then opened and the canal incision is extended anteriorly (Fig. 13, B-C) 10 the 2 o 'clock position (right side). The soft tissues are moved away from the bone using a Key raspatory.
9
'" 11b
12
13
'0
'40
'50
Meatal Skin Flap
Visualization of the entire tympanic membrane using one position of the microscope is made possible by forming a large meatal skin flap that is carefully dissected out of the canal with its inferiorly based pedicle left in place. In the clinical setting, the advantage of this type of flap is that its blood supply is maintained through its pedicle.
Incisions for the Meatal Skin Flap
The meatal flap is incised using a No. 11 blade mounted in a special rounded scalpel handle. The blade is guided along the lines shown in Fig s. 14 a (right ear) and 14 b (left ear).
Two Incisions are made: the first spirally ascending from medial to lateral (Figs. 14a, b; D-C), and the second running medially and circumferentially (D-E).
The spiral incision starts 2 mm tateral to the annulus at 7 o 'clock (right temporal bone) and swings up laterally along the anterior canal wall to meet the previously cut external canal skin at 2 o'dock (C). Be aware that skin incisions in the temporal bone do not bleed and are at times difficult to visualize. Therefore, it is highly advisable to keep in mind the track previously used by the tip of the knife and to make the incision in a step-by-step fashion. The corresponding skin incisions for the left ear are shown in Fig. 14 b.
Temporal Bone Dissecf on - The Zurich Guidelines
A
15"
'5c
Elevation of the Meatal Skin Flap
I 7em
" •
The skin is elevated from the bone using a Fisch microraspatory in the right hand and a microsuction tube in the left hand (Figs. 15 a, b). The microsuction tube should have a length of 7 em to permit the surgeon's left hand to rest comfortably on the head of the patient (Fig. 15 b).
The tiP of the microsuction tube holds the skin away. The amount of negative pressure of the microsuction tube is controlled with the left index finger (Fig. 15 b).
The tip of the microraspatory should always remain in contact with bone. Small movements separate the meatal skin from the bony EAC in the vertical and horizontal planes (Fig. 15 c). A small strip of gauze soaked in saline solution protects the skin during separat ion from the bone with the Fisch microraspatory.
\
Tem]:!
eire
Folic flap, ed, , the t Oeft , Figs USln! sors of th cutti flap knife 50", limb Fig. Fig.
Ete"
CarE ic be. sian mas 'he (Fig.
Temporal Bone Dissection - The Zurich Guidelines
'"
16c
, ,
.. ----'.
Circumferential Skin Incision
D
Following elevation of the lateral part of the meatal skin flap, the circumferential incision of the meatal skin is creat ed, beginning and ending (Fig. 16 a, D-E) 2 mm lateral to the tympanic annulus at 7 o'clock (right ear) or at 5 o'clock (left ear), at the starting point of the spiral incision (see also Figs. 14 a, b). The anterior limb of the incision is carried out using tympanoplasty microscissolS (modified Bellucci scissors) along the edge of the antero-inferior bony overhang of the EAG. The posterior limb of the incision is initiated by cutting through the posterior surface of the meatal skin flap with a No. 11 blade mounted to a rounded scalpel knife (Fig. 16 b). The incision is then continued along the superior canal wall connecting the anterior and posterior limb with straight mlcrotympanoplasty scissolS (Fig. 16 c). Fig. 16 d shows the completed meatal skin flap (see also Fig. 14 a).
Elevation of Meatal Skin Flap from the Tympanic Bone
Gare is taken at this stage to expose the complete tympanic bone, including its lateral sur1ace. This requires an extension of the base of the meatal skin flap from the tympanomastoid suture in the antero-superior direction to include the posterior and lateral sur1ace of the tympanic bone (Fig. 17, C-D).
16b
•
16d
~_c
Medial skin ofEAC
17
c
Skin covering lateral portion of tympanic bone
DE
D
1 1
A
Meatal skm nap
12
18
20a
20b
roc
" \ • • , , , ,
Key raspatory
Temporal Bone Dissection - The Zurich Guidelines
TymparlO- Exposed lateral squamous surface 01 suture tympaniC bone
Medial skm of EAC
I
Tympanomastoid suture
19 .-.-- ----.. ,
Meatal ff- skin flap
-_ .. ,/ ... '
Separation of the skin covering the posterior surface of the tympanic bone is accomplished uSing a Key raspatory. The tip of the raspatory is moved along the lateral portion of the anterior bony canal wall, and then gently rotated anteriorly to completely uncover the superior edge of the tympanic bone (Fig. 18). In this way. the lateral surface of the tympanic bone Is completely exposed from the tympanomastoid to the tympana-squamous suture. This exposure is a prerequisite to performing an adequate circumferential canalplasty (Fig . 19).
Canalplasty
Most commonly. viewing is limited to the antero-inferior portion of the drum owing to an excess of tympanic bone. The correct enlargement of the EAC is obtained by drilling away the overhanging bone with sharp and diamond burrs (Figs. 20 a-c).
In a narrow EAC, It is difficult to identify the antero-inferior tympanic annulus, which may be completely covered by bone. In this situation, a groove (trough) is made in the bony infenor canal wall at 6 o'clock (Fig. 21 ) until the white hne of the tympanic annulus becomes clearly visible. This techmque of the mfenor trough was developed to avoid injuring the facial nerve, jugular bulb or internal carotid artery because these structures are out of reach if the drilling is performed along the inferior EAC wall and remains lateral to the tympaniC annulus (Fig . 21 ).
After identification, the tympanic annulus is progressively exposed as far as the anterior and posterior tympanic spine. When all bone overhangs are eliminated, the complete drum can be viewed without having to readjust the position of the microscope (Fig . 22 a and b).
After correct canalplasty. it may become necessary to apply relieving incisions on the medial meatal skin to return it to a proper position (Fig. 22 b).
,
•
Tempe;
Tympa annull
" B.1.3
Midd for G
Fresh
Then usmg,
This i~ provid
Eleva!
A pol With II terior t handlE and tt tympa from using annuh. sulcus
Elevat conlin the (I~
bone) fixatlO~ terms retatlOi not in
""'ne page the rig betw. and 11 left SJ.
annull the fur
Divisi( (Swint
The el, poster to forn
Temporal Bone Dissection - The Zurich Guidelines
'" Tympanic annulus
TympanIC annulus
21
,
8.1.3 Myringoplasty
• • •
Middle Ear Inspection and Preparation for Grafting
Freshening the Perforation Margins
The margin of the large central perforation is refreshed using ultrafine biopsy forceps (Fig . 23 a) .
This is done before elevation of the tympana meatal flap to provide sufficient stability of the drum,
Elevation of the Tympanomeatal Flap
A posterosuperior tympanomeatal flap is elevated with the microraspatory starting from the pos-terior tympanic spine to expose the malleus handle. the long process of the incus. and the stapes (Fig . 23 b). The chorda /"""" tympani is preserved and separated from the undersurface of the drum using a Fisch Ten%m. The inferior annulus is separated from his bony sulcus using a microdissector (Fig. 23 c).
Elevation of the tympanomeatal flap IS continued to the 4 o 'clock position (on the right side versus 8 o 'clock in a left bone) to gain sufficient anterior access for fixallOn of the underlay graft. Note that the terms Munder_ and overlay~ are used In relation to the bony tympanic sulcus and not in reference to the tympanic membrane (see also 8.3.1. Myringoplasty, page , 9) Never elevate the annulus of the right anten'or tympana-meatal angle between 2 and 4 o'clock (or between 8 and 10 o'clock. respectively. on the left Side). Elevation of the anterior annulus leads to blunting and impairs the functional results of tympanoplasty.
Division of the Tympanomeatal Flap (Swinging-Door Technique)
The elevated tympanomeatal flap is divided posteriorly using tympanoplasty microscissors to form two swinging-door flaps (Fig 23 d).
230
23c
22.
22"
• • • • • • •
_I
13
230
23d
14
,
2 ..
An,_ matleal ligament
Anterior tympaniC spine
24b
240
Posterior tympanic spine
Anterior mallea! process
Temporal Bone Dissection - The Zurich Guidelines
Inspection of the Ossicular Chain
Enlarge the postero-superior canal wall with a small curette 10 expose the anterior malleal process and ligament, the InclJdo-malieal toint, and the complete stapes (Figs. 24 a, b).
Check the integrity of the ossicular chain and verify its mObility. Disarticulate the incudo-stapediaJ joint using a Joint knife (Fig . 24 b) to prevent cochlear damage while manipulating the ossicles (particularly the malleus handle). Epithelial debris is cleaned from the malleus tip using a 1.5 mm 45 0 hook while the malleus handle is lateralized with a second hook (Fig. 24c),
Adjunctive Anterior Fixation of the Underlay Graft (Subtotal Perforation)
In the presence 01 subtotal or anterior perforations, the tympanic annulus is separated from the sulcus between 1 and 2 o'clock (right ear) (Fig. 25 a). The antero-superior portion of the temporalis fascia will be kept in position through this gap. This eliminates the need to introduce Gelfoam 1M into the protympanum to fix the fascia against the lateral wall of the latter.
Drilling of the New Tympanic Sulcus
A new tympaniC sulcus is drilled with a small diamond burr along the medial bony edge of the EAC between 4 and 2 o'clock (Fig. 25 b). This ledge of bone is used for later positioning of the fascia as seen in the insert of Fig. 25 b .
",
-..... ••••
I , , , , , , , , , .. , '. , \ , , , , , ,
\ .•.. ~ .. '. 25b ~.~, ••• • . " '.': : ...
••••••••••
Tem
Fixatil
In su under! points
B.l.4
The. eusta( mucO! mined paraliE
The. identlf ble thr The., tonize. be ,en 0","", (Fig. 2
B.l.5
Water
IrrigatE bulb a the ml case, cranial
28
Temporal Bone Dissection - The Zurich Guidelines
Fixation Points for Underlay Grafting
In subtotal and large antero-inferior perforations, the underlay fascial graft will be supported by the following points:
CD On the ledge of the new antero-inferior tympanic SUl-cus.
<V Under the malleus handle. CD On the posterior tympanic sulcus and chorda tympani. @ On the gap between the antero-superior tympanic
annulus and sulcus.
B, 1.4 Antrotomy
The antrotomy is carried out when the function of the eustachian tube is questionable or when the middle ear mucosa is abnormal. The poSition of the antrum is determined by the intersection of the temporal line and a line parallel to the posterior canal wall (Fig. 27).
The middle cranial fossa dura and the sigmoid sinus are identified by drilling away the bone until they become visible through the last shell of covering bone (skeletonizarion) . The antrum is found by removing the bone along the skeletonized middle cranial fossa dura. No bone should be removed over the entrance of the EAC. The antrum is opened until the lateral semicircular canal is exposed (Fig. 28).
B.1.5 Epitympanotomy
Water Test for Epitympanic Patency
Irrigate the antrum with water dispensed from a rubber bulb and ensure that the Ringer's solution flows freely into the middle ear and out of the ear canal. If this is not the case, drill away the bone along the skeletonized middle cranial fossa in an anterior direction until the incus and
28
• / ,
,
,
27
,
"
,
, , , , , , , ,
"
15
malleus head have been identified and exposed (epitympanotomy). Obstructing scars or thickened mucosa surrounding the ossicles are removed to achieve adequate patency of the aditus ad antrum (epitympanecromy) (see Fig. 64 , page 32).
29
16
300
30c
,
,
Retroauncular skin incision
Stab incision for drain
Temporal Bone Dissection - The Zurich Guidelines
30b
Transmastold drain
8 .1.6 Transmastoid Drainage of the Antrum
After exposmg the antrum, a groove is drilled posteriorty along the sinodural angle to guide the transmastoid drain (Kala-Drain) (Fig. 30 a). The polyethylene drainage tube, having an outer diameter of 5 mm, has been bent by placing it over a curved metal stylus and healing it in an oven at a temperature of BOoe. The angle of the bent lube is 110°.
The Iransmastoid drain is placed with its bend in the antrum through a separate relroauricular slab incision using a curved clamp. (Figs. 30b, c).
B,2 Tympana-Mastoidectomy
General Considerations
The sleps required for a closed Mastoido~Epitympanectamy with Tympanoplasty (MEl) are:
Meatoplasty, Ganalplasty. Epltympanectomy, Mastoidectomy, Posterior Tympanotomy. Osslculoplasty, Myringoplasty, and Mastoid Dramage.
Some of these surgical steps are the same as for retroauricular tympana-antrotomy and have been discussed in the preceeding chapter (see page 7).
\
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Iden
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\ \ · \ , " " , f
• I I , ,
• I I I I ( ,
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Temporal Bone Dissection - The Zurich Guidelines
B.2.1 M astoidectomy
Identification of the Facial Nerve (Fig. 31)
• Enlarge the antrotomy superiorly by skeletonizing the middle fossa dura. Perform the epltympanotomy to expose the incus and malleus head. Identify the tympanic segment of the facial nerve inferior to the lateral semicircular canal <D.
• Skeletonize the sigmoid sinus and expose the sin' odural angle. Do not work in a hole or underneath bony edges!
• Expose the lateral surface of the digastric muscle along the mastoid tip. Follow the superior edge and lateral surface of the digaster muscle anteriorly to identify the stylomastoid periosteal fibers (curving antero-superior). and skeletonize the stylomastoid foramen $.
• Expose the posterior semicircular canal. Remember that the pyramidal segment of the facial nerve is Situated 2 mm antero-Iateral to the inferior edge of the posterior semicircular canal <D.
• Use the lateral and posterior semicircular canals and the stylomastoid foramen to estimate the course of the facial nerve. Skeletonize the mastoid segment of the facial nerve in a retrograde fashion using large diamond burrs to drill over a wide field on the compact bone covering the lateral surlace of the nerve.
B.2.2 Posteri or Tympanotomy
The space between the pyramidal segment of the facial nerve, the chorda tympani, the buttress over the lateral process of the incus, and the posterior canal wall is called the facial recess (Fig. 32). There is great variability in size and pneumatization of this area. The bone between the pyramidal segment and the chorda tympani is drilled away (Fig . 33) while keeping an eye on the skeletonized mastoid and pyramidal segments of the facial nerve. The resulting opening to the middle ear is the posterior tympanotomy. Avoid exposing the facial nerve (leave a small shelf of bone to cover and protect the nerve) or touching the Incus With the burr. and do not injure the chorda tympani and the tym· panic annulus. Do not make the posterior canal wall too thin to avoid delayed atrophy (Fig . 33).
17
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18
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Temporal Bone Dissection - The Zurich Guidelines
With the facial nef'Ve in view, the facial recess can be enlarged as much as possible. If the mastoid is narrow, the bony buttress behind the posterior ligament of the incus is removed to gain sufficient space. A diamond burr is used to lower the bone covenng the lateral semicircular canal, and the pyramidal and distal tympanic segments of the fallopian canal. This will also expose the chorda tympani (Fig. 34), Through the posterior tympanotomy and epitympanotomy the following middle ear structures should be identifiable:
• stapes and stapedial tendon
• tympanic segment of the facial nerve
• round window
• incus with short and long process
• mal leus head, cochleariform process and tensor tympani tendon
• eustachian tube orifice (occasionally, Fig . 45)
8 .2.3 Epitympanectomy
The incudo-stapeclial joint is separated , and the incus is mobilized with a 1.5 mm. 45° hook (Fig. 35a) then removed by lateral rotation , preserving the chorda tympani (Fig . 35 b). The long process of the incus may be cut with a malleus nipper when the integrity of the chorda is at risk.
The chorda is separated from the undersurtace of the malleus, and the malleus neck is cut with a malleus nipper (Fig. 35 e) or, if the anterior malleal ligament is hyalinized, with a 0.8 mm diamond burr (c.f. Fig . 58 e). The malleus head and the chorda tensor fold are removed to ensure free communication between protympanum and supratubal recess.
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Temporal Bone Dissect ion - The Zurich Guidelines
B.3 Myringo- and Ossiculoplasty In Closed Cavities
8.3.1 Myringoplasty
General Considerations
The terms underlay and overlay are used in relation to the bony tympanic sulcus and not. as is usual . in reference to the tympanic membrane, Therefore. anterior underlay means that the temporalis fascia (or the piece of wet paper used for it) is placed under the anterior tympanic sulcus in contact with the lateral wal l of the protympanum. In this case, Ihe tympanic annulus and anterior remnant of the tympanic membrane remain over the anteriorly underlaid fascia. Posterior overlay means that the fascia is situated over the posterior bony tympanic sulcus. When repositioned, the tympanic membrane remnant (or tympanomealal flap) will cover the posteriorly overlaid fascia.
Underlay Grafting
For training purposes, use a wet piece of paper from the surgical glove packing . An inciSion IS made with a knife according 10 the expecled position of the malleus handle (Fig. 36 a).
The swinging-door Iympanomeatal flaps are elevated (except antenorty between 2 and 4 o 'clock) 10 create sufficient space for inserting the graft under the anterior margin of the perforation, The graft is placed under the malleus handle and rests over the chorda and the pastero-inferior tympanic sulcus (Fig . 36 b).
For subtotal or large anterosuperior perlorations, the graft should also be fixed between the sulcus and annulus tympanicus at the 1 0 'clock position for the right bone and at the 11 o 'clock position for the left ear.
36b
37 (j)
The graft is supported althe following points (Fig . 37):
<D On Ihe inferior tympanic sulcus. @ Under the malleus handle. <D On the posterior tympanic sulcus and the chorda
tympani. @) In the gap created antero-superiorly between the
tympanic annulus and tympanic sulcus.
19
20
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38
Temporal Bone Dissection - The Zurich Guidelines
39.
39b
B.3.2 Ossiculoplasty
8 .3.2.1 Incus Interposition
8 .3.2.2 Autologous Incus
In the presence of intact stapes, malleus handle and anterior half of the drum, the preferred type of reconstruction is the interposition of the autologous incus.
Measuring the Length and Angle of the Implant
The correct length and angle of the implant is measured using a Fisch microraspatory that is 2.5 mm in length.
Shaping the Autologous Incus
The incus body is held firmly using a small curved clamp while drilling with a diamond burr (Fig. 39a). The long process and the posterior part of the incus body are shortened. Keep in mind that the plane used to shorten the incus body determines the angle of the interposed ossicle. The articular surface of the incus is carved, taking into consideration the inclination of the malleus handle (Fig. 39 b). A notch for the stapes head is drilled on the opposite side using 0.6 and 0.8 mm diamond burrs (Fig. 3ge).
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Temporal Bone Dissection - The Zurich Guidelines
40.
Interposition of the Modified Autologous Incus
The modified incus is rotated in contact with the malleus handle over the stapes head using the largest microsuction and a 1.5 mm, 45° hook (Figs. 40 a, b). The chorda tympani runs cranial to and stabilizes the interposed incus (Figs. 40 a-c).
B.3.2.3 Titanium Incus
A Titanium Incus Prosthesis (KARL STORZ, Tuttlingen, Germany) is used when the autologous incus is not available (Fig. 41 a). Prosthesis length selection (3, 4 or 5 mm) depends on the measurement obtained with the Fisch microraspatory (see Fig. 38). The prosthesis surlace connecting with the stapes head and malleus handle should be rough. This is achieved by dri lling the contact surfaces with a diamond burr. For this purpose, the titanium incus should be held with special incus-holding forceps (Figs. 41 b, c ). The t itanium incus is transported into the middle ear and introduced between the malleus handle and stapes head using a 2.5 mm, 45° hook inserted through holes made for this purpose (Fig. 41d). The prosthesis is posit ioned exactly as an interposed autologous ossicle (Fig. 41 e).
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C Stapedotomy
General Considerations
Stapedotomy means the creation of a small calibrated fenestration into the stapes footplate. The same name is frequently used to indicate the introduction of a stapes prosthesIs between the incus and vestibule, regardless of whether the opening into the footplate is well calibrated or consists of a partial removal of the footplate (~small fenestra stapedectomyj. From the authors' point of view, the definition of "stapedotomyN should be limited to the former situation and the latter should be cal led a "partial stapedectomy. N
The introduction of a stapes prosthesis from the malleus to the vestibule has been called ~vestibulopexy. " This term does not address whether the prosthesis reaches the vestibule through a calibrated opening, or through a partial or total stapedectomy. To avoid this confusion, the authors have introduced the terms incus-stapedotomy and mal/eostapedotomy for the exclusive use of a stapes prosthesiS from the Incus or malleus handle in conjunction with a stapedotomy opening.
To achieve a stapedotomy opening through the footplate on a regular basis, It has proven of value to reverse the classic steps of stapedotomy and to create the calibrated opening before removing the stapes arch. In this case, the diameter of the stapedotomy opening should not exceed 0.5 mm, and the corresponding diameter of the stapes piston should be of 0.4 mm.
C.1 Incus·Stapedotomy
Endaural Skin Incision
The endaural skin incision (A-B in Fig. 42 a) is made using a No. 15 blade at the 12 o'clock position between the tragus cartilage and root of the helix. The soft tissues are cut to the level of the bony entrance of the canal (remove excess soft tissues over the bony external ear canal to gain sufficient exposure in the temporal bone specimen).
Tympanomeatal Flap
The tympanomeatal incisions are made with a NO.l1 blade mounted in a special rounded scalpel handle.
The posterior limb of the tympanomeatal flap begins at 8 o 'clock, ascending spiraly from the tympanic annulus to the lateral edge of the external auditory canal (C-A in Fig. 42 b). The anterior limb is carried out from the 1 o'clock position to the Inferior edge of the endaural incision (D-A in Fig. 42 b).
NOTE: A larger tympanomeatal flap (as for malleo-stapedotomy, see page 28) is used whenever total or partial fi xation of the malleus is suspected.
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Canalplasty
While elevating the tympanomeatal flap, the bony overhang of a prominent tympanosquamous spine or a protruding antera-superior canal wall needs to be removed to adequately inspect the anterior malleal process and ligament (Fig s. 43a-c). A curette or diamond burr is used for this purpose (do nol separate the Iympanomeatal flap from the tympanic sulcus and incisura Aivini during this step to avoid irrigation of the middle ear with contaminated Ringer's solution).
Elevation of Tympanomeatal Flap
The most important landmark in this step is the posterior tympanic spine (posterior end of the incisura tympaniea Aivini). The Iympanomeatal flap is elevated first from the posterior spine using a Fisch microraspatory. Care is taken to keep the chorda attached to the flap (Fig. 44 a).
Enlargement of the Supero-Posterior Canal Wall
The bone covering the oval window, the inferior edge of the incudo-malleal joint and the anterior malleal process are removed using a curette. The rotational movements of the curette should be directed from medial to lateral to avoid trauma to the chorda and incus (Fig. 44 b).
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Temporal Bone Dissection - The Zurich Guidelines
• 6
Exposure of the Oval Window
The exposure of the oval window is correct when the following structures are visible (Fig_ 45):
• Pyramidal process with the stapedial tendon • Oval window with the stapes and incudo-stapedial
joint
• Tympanic segment of the facial nerve • Infenor incudo-malleal JOint • Lateral (short) process of the malleus • Anterior malleal process and ligament
Preparation of the Stapes Prosthesis
A malleable measun'ng rod is used to determine the d islance between the footplate and the lateral surface of the incus (Fig . 46). This measurement should be increased by 0.5 mm to account for the protrusion of the prosthesis piston into the vestibule. The resulting total length of the prosthesis will average 5.2 mm. A 0.4 x 8.5 mm Titanium Stapes Prosthesis (KARL STORZ. Tuttlingen. Germany) is trimmed on a special Titanium Cutting Block (Fig. 47) and placed in the preformed 0.4 mm hole for later use.
The stapes prosthesis is available in two other sizes: 0.4 x 10 mm and 0.4 x 7 mm. The longest prosthesis is used in deep middle ears (partially malformed ears), the shortest in shallow middle ears (partially open cavities). The different
•
Ierlgths relate to the different distance between prosthesis .. loop and 0.4 mm cylinder.
Perforation o f the Foo tplate
A calibrated opening of 0.5 mm diameter is made in the safe area (the central area between the middle and inferior third of the stapes footplate) where the saccule and utricle lie more than 1 mm below footplate level (Fig. 48 a). The stapedotomy opening should be positioned in such a way that the prosthesis will remain perpendicular to the footplate .
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Manual perforators
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48b
A set of four manual perforators (0.3, 0.4. 0.5 and 0.6 mm diameters. Fig . 48b) is used to create the stapedotomy opening. The periorators are rotated back and forth between thumb and index finger. The tip of each periorator is only partially introduced into the vestibule. The correct size of the opening (0.5 mm) is confirmed with a 0.4 mm caliper (Fig. 48 c).
Introduction and Fixation of the Stapes Prosthesis
The stapes prosthesis is picked up from the cutting block using large straight smooth alligator forceps (Fig. 49 a). The piston IS first placed over the stapes footplate and aligned with the long process of the incus. The length of the prosthesis is correct if the piston loop exceeds the la teral surface to the incus by 0.5 mm (Fig. 49 b).
II the prosthesis is the correct length, it is moved over the stapedotomy opening with a 1.0 mm. 45° hook and carefully advanced into the vestibule (Fig. 49 b). The loop is then crimped over the incus with small straight smooth alligator forceps (Fig. 49 c).
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Temporal Bone Dissection - The Zurich Guidelines
Tympanoplasty
SOb
Removal of the Stapes Suprastructure
With the prosthesis in place, the incudo-stapedial joint is separated with ajelnt knife (Fig . 5Oa). the stapedial tendon is sectioned with tympanoplasty microscissors (Fig. 50 b), the posterior crus is cui with cruratamy scissors that are controlled with both hands (Fig. 50 c), and the anterior crus is crushed at the level of the footplate with a 2.5 mm, 45° hook (Figs. 50 d and e).
The stapes arch is removed, and final mobility of the ossicular chain is confirmed. There should be no free movement of the prosthesis loop when either the incus or malleus is moved (Fig . 50 f) ,
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52
Temporal Bone Dissect ion - The Zurich Guidelines
1.5 mm 45~ Hook
Sealing of the 5tapedotomy Opening and Repositioning of the Tympanomeatal Flap
Three connective tissue pledgets from the endaural incision are placed around the stapedotomy opening (Fig. 51 a) Venous blood obtained from the cubital vein of the patient prior to surgery and one drop of fibrin glue are used to seal the oval window niche (Fig. 51 b). The tympanomeatal flap is repositioned, and two small Gelfoam ™ pledgets soaked in corticosporin are used to keep the flap in poSit ion (Fig. 52).
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C.2 Malleo·Stapedotomy
Endaural Approach
This surgical step is identical to incus stapedotomy (Fig. 423, page 22).
Tympanomeatal Flap
The tympanomeatal flap used for malleo-stapedotomy is larger than that described for incus-stapedotomy. The posterior limb (C-B. Fig. 53) is the same, but the anterior limb (D-B. Fig. 53) extends to 4 o'clock on the right side and 8 o'clock on the left.
The soft tissues are elevated from the underlying bone using a Key raspatory. At this stage, the endaural retractors are replaced to obtain maximal exposure without injuring the skin margins (this surgical step does not apply to the temporal bone). The tympanomeatal flap is raised from the underlying bone with a Fisch microraspatory and a microsuction tube (Fig. 15, page 10). In Figure 54, the anterior and posterior tympanic spines are exposed for anatomical demonstration. In reality, the tympanomeatal flap should not be separated from the Incisura tympanica Rlvini before
55
Temporal Bone Dissection - The Zurich Guidelines
A
54
Spina tympani anteoor
Spina tympani posterior
\
c
D
completmg the canalplasty to avoid contamination of the middle ear cavity with contaminated saline solution used for irrigation while drilling .
Antero-superior Canalplasty
The canal skin is elevated from the wall of the ear canal with a Fisch microraspatory. The antero-superior overhang of bone is then removed with sharp and diamond burrs until the anterior and posterior tympanic spines can be identified (see also Fig. 43 b, page 23). The tympanomeatal flap should remain attached to the bone at the entrance of the middle ear until drilling is completed to avoid contaminating the cavum tympani with irrigation fluid.
Elevation of the Tympanomeatal Flap
The tympanameatal flap is first elevated from the posterior tympanic spine using a left Fisch microraspatory (right ear) that is introduced under the rim of bone lateral and superior to the chorda tympani. The Shrapnell membrane is then elevated from the malleus neck and lateral malleal process until the anterior tympanic spine and the beginning of the anterior tympanic annulus become visible.
Antenor malleal ligament
Spona tympani posterior
56
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Temporal Bone Dissection - The Zurich Guidelines
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Exposure for Malleo-Stapedotomy
Pyramidal process
The correct exposure for malleo-stapedotomy is obtained by using a curette to enlarge the supero-posterior edge of the bony external canal (see Fig. 44, page 23). The following structures should be exposed (Fig. 57 b):
• Pyramidal process with the stapedial tendon • Oval window with the stapes and incudo-stapedial
Joint • Tympanic segment of Fallopian canal • Inferior part of the incudo-malleal loint • Lateral malleal process and malleus neck • Anterior malleal process and ligament • Anterior tympanic spine
The corda tympani should be kept intact whenever possible. Remember that an intact chorda is the calling card of the otologist.'
Malleus nipper
58b
Incudo malleal jOint
57b
Antenor malleal process
Removal of Incus and Malleus Head
29
The malleo-stapedotomy is performed when there is total or partial fixation of the malleus and/or incus. A fixed incus is removed after cutllng its loog process with a malleus nipper to avoid damage to the chorda tympani during extraction (see also Fig. 35 c, page 18). The malleus nipper is not used to section the malleus neck because this maneuver would leave the anterior malleal process intact (Fig. 58 b).
CalCi fied anterior malleal ligament
30
: ::::::-
59
Temporal Bone Dissection - The Zurich Guidelines
A fixed malleus head is removed most effectively by cutting Its neck with a 0.6 or 0 .8 mm diamond burr (Fig. sac). While drilling. the malleus handle is held with a large toothed straight alligator forceps controlled by the left hand. The drilling starts over the anterior matleal process, which is just anterior to the lateral process (Fig . SSe) and continues in a superior and antero-poslerior direction across the malleus neck. This C· shaped line of drilling permils the anterior malleal process to be included in the resection. Great care is taken to keep the chorda tympani intact. The chorda tympani runs under the anterior malleal process from which it must be separated by using a hook prior to drilling.
Preparation of the Stapes Prosthesis
The previously mentioned Titanium Stapes Prosthesis, 0.4 mm diameter and 8.5 mm length, is used for both incus-stapedotomy and malleo-stapedotomy. The initial steps for preparing the prosthesIs are the same for both types of stapedotomy (see page 24). The average distance between the proximal malleus handle and the stapes footplate is 6.5 mm (including 0.5 mm to allow for protrusion of the piston into the vestibule). The Titanium Stapes ProsthesIs is trimmed on a titanium cutting block (Fig. 59). The surface of the cutting block should be humidified with saline solution to eliminate unnecessary movement of the prosthesis. The diameter of the prosthesis loop is enlarged to the size of the malleus handle by moving it along a 1.5 mm, 450 hook with watchmaker forceps and then stored in the 0.4 mm hole of the cutting block.
Shapin9 of Prosthesis-Shaft for the Mal1eus Handle
The shaft of the prosthesis may be bent along various planes on the cutting block to accommodate the anterior position of the malleus. This is done while the prosthesis is in the 0.4 mm hole of the cutting block by gently bending it to the correct extent by pushing the shaft with watchmaker forceps (Fig. 60). This same maneuver can be performed in a lateral d irection if required by the steep position of the malleus handle.
60
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Temporal Bone Dissection - The Zurich Guidelines
Perforation of the Footplate
This slep is performed using manual perforators as for an incus-stapedolomy. An Erbium-YAG laser is used in special cases (e.g. mobile foot plate).
Removal of Stapes Arch
The stapes arch is removed after perforation of the lootplate. Both crura are cut using crurotomy scissors (see Fig. 50 c , page 26). The stapedial tendon is cut last to insure stability while cutting the crura.
Introduction and Fixation of the Stapes Prosthesis
The picking up and the introduction of the prosthesis in the middle ear are done in a manner similar to incus-stapedotomy (see Fig . 49, page 25). The exposure given by the large tympanomeatal flap and the anterosupet'lor canalplasty is such that both, the malleus handle and the footplate are visible with one position of the microscope. The prosthesis is first placed on the footplate to ensure that the length and bend are adequate (the prosthesis cylinder must be perpendicular 10 the foot plate). The prosthesis cylinder IS then introduced into the vestibule for 0.5 mm (measured from the lateral surface of the footplate) using a 1 mm, 45° hook.
Fixation of Stapes Prosthesis
The prosthesis loop is attached to the malleus handle just distal to the lateral malleal process (Extensive separation of the drum from the malleus handle should be avolded.~. Crimping the prosthesis to the malleus handle is performed uSing large (Fig. 61 a) and small smooth straight alligator forceps (Fig. 61 b). Each forceps is held with both hands. The prosthesis loop should be immobile after crimping.
Sealing of the Stapedotomy Opening and Repositioning of the Tympanomeatal Flap
These surgical staps are done as for incus-stapedotomy (see Fig. 51, page 27).
Titanium stapes prostheSIs (0.4 mm diameter)
."
Titanium stapes prosthesis (0. 4 mm diameter)
" .
31
32
62
MC' Dura
63
64
1
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RetrOSlgmold cells
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Temporal Bone Dissection - The Zurich Guidelines
o Open Cavity (Open MastoidoEpitympanectomy or Open MET)
General Considerations
The surgical principles of an open MET are:
<D rad/cal exenteration and
CD adequate exteriorization
of the pneumatic cell tracts. In clinical situations, the open MET is often associated with partial obliteration of the cavity using an occipital myosubcutaneous flap (METQ. or Mastoidectomy, Epilympanectomy, Iympanoplasty and Qbliteration with myosubcutaneous flap). The first steps of an open-cavity procedure (Retroauricular Skin Incision and Canalplasty) are the same as for a closed-cavity tympanomastoidectomy. If two temporal bones are used for the dissection, the bone available for performing the open-cavity procedure was already used for the incus- and malleostapedotomy. Therefore, a modified meatal skin flap must be used for the canalplasty.
Checklist for Bone Work In Open MET
The recommended sequence of bone removal for an open MET is (Fig. 62):
<D Wide lateral bone removal over the root of the zygoma with skeletonization of the middle cranial fossa dura and sigmoid sinus, exposure of digastric muscle, and skeltonizallOn of stylomastoid foramen.
® Identification of the tympanic segment of the fallopian canal and posterior bony semicircular canal, and lowering of the facial ridge.
CD Radical exenteration and extenonzation of the retrofacial. retrolabyrinthine and the retrosigmoid cells.
<D Radical exentera tion and exteriorization of the epitympanum (supralabyrinthine and supratubal recesses).
® Extended antero-inferior cana/plasty.
0.1 Mastoidectomy
Lateral Bone Removal
Mastoidectomy begins with wide removal of lateral bone from the zygomatic arch to the sinodural angle (Fig. 63). The dissection is continued with skeletonization of the middle cranial foss dura, the sigmoid sinus and sinodural angle. The lateral semicircular canal is identified in the antrum and the lateral surface of the digastriC muscle is exposed (Fig. 64).
Epitympanotomy
The antrum is opened and the dissection is extended anteriorly to periorm an epitympanotomy (Fig. 64 and Fig. 28, page 15). The tympanic segment of the facial nerve is identified at the inferior edge of the lateral semicircular canal (see also Fig. 32, page 17). The bone at the mastoid tip covering the lateral suriace of the digastric muscle is removed. No bony overhangs along the d issection field should remain (particularly over the middle cranial fossa dura and behind the sigmoid sinus).
,
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56
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Temporal Bone Dissection - The Zurich Guidelines
65
Stylomastoid foramen
Stylomastoid periosteal fibres
Mastoid Tip Surgery and Facial Nerve Identification
The superior edge and the lateral surface of the digastric muscle is followed until the stylomastoid periosteal fibers are visible. The stylomastoid foramen is identified and the bone along and lateral to the white periosteal fibers is removed (Fig . 65). At this stage, a crack forms lateral to the stylomastoid foramen , mobilizing the remaining mastoid lip (see Fig. 71 , page 35),
Lowering of the Facial Ridge
The posterior semicircular canal is identified. The three essential landmarks are now visible, determining the position of the mastoid and pyramidal segments of the facial nerve (Fig. 66). These are:
ill the tympanic segment of the facial nerve <D the inferior edge of the posterior semicircular canal,
and <D the stylo-mastoid foramen .
The anterior remnant of the superior canal wall is removed 10 fully expose the ossicular chain .
Completion of Mastoidectomy
The incus is disarticulated from the stapes, and Ihe incus and malleus are removed. If the malleus handle can be preserved, the tensor tympani tendon should also be preserved to stabilize the latter. The retrofacial (1), the retrolabyrinthine (2) and the retrosigmoid (3) cel l t racts are exenterated and exteriorized. The jugular bulb is skeletonized (Fig . 67: Inserts a and b)
/
66
2
67
67.
TympaniC segment of facial nerve
~(_Stylomastoid ::.- fOl"amer1
67.
33
of
canal
34
,
68
70
Temporal Bone Dissection - The Zurich Guidelines
Sinus epitympani
' .........
69
0.2 Epitympanotomy
Epitympanotomy
The supralabyrinthine (3) and supratubal (4) recess are exenterated and exteriorized to expose the ampullary end of the lateral and superior semicircular canals (Fig. 68). The awareness of the close proximity of the labyrinthine and tympanic segments of the facial nerve prevents injury of the geniculate ganglion (5).
0.3 Completion of MastoidoEpitympanectomy
Exteriorization of Antero-Superior Cavity
An extensive antero-inferior canalplasly is per10rmed to remove all bone overhangs at the root of the zygomatic arch (Fig. 69: Insert). The tympanic bone should be lowered to meet the level of the stylomastoid foramen (6). A diamond burr is used when neanng the mandibular condyle while watching for color changes that indicate its proximity.
New Tympanic Sulcus
If there is no remnant tympanic annulus, drill a new tympanic sulcus (Fig. 70, (7)) in the bony canal wall from the 1 to 9 o'clock poSItions (right side). The resulting bony ledge will accommodate the fascial graft used for myringoplasty. The profile and position of the new ledge are shown in the inserts shown in Figure 70.
If an anterior tympanic membrane remnant is present, the new sulcus is performed from 4 to 9 o'clock because the tympanic annulus is left in situ along the sacred anten'or tympano-meatal angle (see Figs. 25, 26 and 36).
\
\
I
I
Tempor
" Mastoid
The mru ture line foramen to latera the soft toid tip.
E.1. T
General
This typ an intac ic memt used. If ",",0"'" bone; i.E aerated General
Myring(
A thick preser"IC die ear (Fig. 72-
A fresh ratory) i: ic mem sulcus segmel'
The sla fascia (( low, a ~ used to
I
I
I
)
Temporal Bone Dissect ion - The Zurich Guidelines
71 72a
Mastoid Tip Removal MicrosuClIOn N' 2
The mastoid tip is removed with rongeurs along the frac-
Ge/film or thick silastic
ture line produced during identification of the stylomastoid 2.5 mm. 45~ Hook foramen (see Fig. 72 a). The rongeur is rotated from medial to lateral, and a large curved scissors is used to separate the soft tissues attached to the undersuriace of the mastoid tip.
E. Tympanoplasty (Myringo- and Ossiculoplasty in Open Cavities)
E.l. Type III Tympanoplasty
General Considerations
This type of reconstruction is periormed in the presence of an intact mobile stapes. If a portion of the anterior tympan- 72b ic membrane remains intact, an anterior fascial underlay is used, If no tympanic membrane is left, an overlay graft becomes necessary (an overlay being a graft placed over bone; i.e., over the old or new tympanic sulcus. limiting the aerated middle ear space: see also B.3.1. Myringoplasty, General Considerations, page 19).
Myringoplasty with Anterior Fascial Underlay
A thick (1 mm) Silastic· sheeting (Gelfilm fM is used in the presence of an active infection) is introduced into the middle ear up to the tympanic ost ium of the eustachian tube (Fig. 72a).
A fresh temporalis fascia (a wet piece of paper in the laboratory) is placed under the anterior remnant of the tympanic membrane (underlay grafting) over the new tympanic sulcus inferiorly. and over the facial ridge and tympanic segment of the fallopian canal postero-superior (Fig. 72 b).
The stapes head should be higher than the surrounding fascia (outward bulging. Fig. 72 c). If the stapes head is too low. a piece of tragal or conchal cart ilage with a notch is used to increase its length. ",
New Tympanic Sulcus
35
36
73.
74. 74b
Holding forceps
740
Blood or "".. ___ .... , fibrin glue
74<1
Temporal Bone Dissection - The Zurich Guidelines
Temporalis Fascia
73b
When the tympanic membrane is absent, a thick (1 mm) Silaslic sheeting is introduced into the middle ear to avoid scar tissue formatIon between the fascia and mucosa (Fig . 73 a). The fresh temporalis fascia (or tragal perichondrium) is then placed over the circumferential new tympanic sulcus, the tympanic segment of the fallopian canal and the semicanal of the tensor tympani muscle (overlay grafting) (Fig. 73 b),
E.2 Total Reconstruction of the Ossicular Chain
E.2.1 The Fisch Titanium Total Prosthesis
E.2.1.1 Preparation of Prosthesis The Fisch Titanium Total Prosthesis (FTTP) is composed of an L-shaped shaft with head and a shoe (foot) with spike (Fig. 74 a, b). The distance between the tympanic membrane and the footplate is determined with the malleable measuring rod. The FTTP can be used with or without the shoe.
Prosthesis with Shoe
If the shoe IS used, 0 .5 mm should be subtracted from the total measured length to account for the additional length of the shoe in the assembly.
The FTTP shaft is introduced in the 0.6 mm hole of the Titanium Cutting Block (see Fig . 59) and trimmed to the desired length (Fig . 74 a). The foot is placed into the 1.0 mm hole of the cutting block (Fig. 74 b). The F I I P shaft is grasped with a special curved holding forceps and introduced into the shoe (Fig. 74c). A drop of blood or fibrin glue can be used to increase the stability of the assembled prosthesis (Fig . 74 d).
If more strength is required, a special crimping forceps can be used to squeeze the foot tightly to the shaft.
Tempora
Prosthe
Them narrow c is also u inner eal in the ve shaft is ( 81 , pagE
E.2.1.2
Angulat
The thie. the plan drum pc 75a and
Size anc
The m Special meier of one or 1\
It is alsc thesis hI It any dE
7 ..
7&
Temporal Bone Dissection - The Zurich Guidelines
Prosthesis with Cartilage Disc
The mp is used without a shoe if the oval window is too narrow or the stapes arch remains in place, The shaft alone is also used if the patient does not accept the risk to the inner ear deriving from the introduction of the shoe's spike in the vestibule. If the shoe is not used, stabilization of the shaft IS obtained by using a cartilage disc (see Figs. 80 and 81 , pages 39 , 40).
E.2.1.2 Shaping the Prosthesis Head
Angulation
The thickness of the FTIP head is only 0.1 mm. Therefore. the plane of the prosthesis head can be adapted to the drum position in the vertical and horizontal planes (Figs. 75a and b).
Size and Shape
The mp head is 0.' mm thick and 5 mm in diameter. Special titanium scissors can be used to reduce the diameter of the prosthesis head to 3 or 4 mm by cutt ing away one or two outer rings (Figs. 76a, b and c).
It is also possible to remove the anterior half of the prosthesis head (when the malleus handle is present) or to give It any desired shape (Fig. 76 d).
5mm
76.
3mm • •
76c
75.
75'
76'
7'"
4 • • • • • • • 1
Vertical plane
Hanzontal plane
, mm
.. • • • • • • : r
I> \ • • • • • ~
? • Scissors for titanium total prothesis
37
.
•
38
'70
77,
,.
0 00 0 ° 0 °<>0 <>
77'
77'
Holding forceps
Temporal Bone Dissection - The Zurich Guidelines
length of L-shaped Arm
Another unique feature althe FTTP is the ability to change the length of its l-shaped arm to meet the specific requirements of the middle ear anatomy. particularly when the prosthesis head is reduced in size. For this purpose, the FTTP is grasped with two watchmaker forceps and straightened, then bent in the deSired angle as shown in Fig. 77 a-d.
E.2.1.3 F I I P Handling
Holding Forceps and Microsuction Tube
The FTTP is transported from the cutting block to the middle ear with special curved holding forceps or with the largest microsuction tube.
_ Mk:rosuction ,"be
Tempora
, ..
Rotalier
The 1001 part of t position held in II manipul. using on the pros ducing c tension t 79a ana cartilage moveme flexibilit~ connectl
'.' ~~ n' .' ." , I '" I' .,' 'e (;)
90a
•
Temporal Bone Dissection - The Zurich Guidelines
•
,
79.
Rotation of the Head of F I I P under the Drum
The loot of the FTIP is fixed with the spike on the central part 01 the footplate. The FTIP head is then rotated into positioo by raising the pars tensa with a 2.5 mm. 45" hook held in the left hand, while a second hook (1.5 mm, 45") IS manipulated by the nght hand to rotate the prosthesis head using one of its multiple central holes. The final position 01 the prosthesis head is under the central pars tensa, producing a slight bulging of the latter as a sign of sufficient tension to keep the prosthesis in the deSired position (Figs. 79 a and b). There is no need to cover the prostheSis with cartIlage because the prosthesis head can follow the movements 01 the tympanic membrane because 01 the flexibility of the 0.2 mm diameter angled titanium band connecting it to the shaft.
''''
Stabilization of the F II P on the Stapes Footplate. Use of Shoe with Spike
39
The best stabilization of the FTIP to the foot plate is achieved by perforating the central part 01 the stapes lootpiate to allow introduction of the 0.3 mm long spike of the prosthesis shoe (Fig. 80 a). The perforation is made with the smallest manual perforator. A mobile footplate is fixed during this maneuver with a 1.0 mm, 45" hook held in the left hand, which pushes the footplate slighty against the margin of the oval Window. An Erbium-VAG laser can also be used to perforate a mobile footplate. Usually one single pulse of 35 mJ is sufficient for this purpose.
Tragal cartilage f... ~ Tragal cartilage ,
• • ," f ',.
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~
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80.
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40
Endaural skin InciSIOn
81.
81.
81,
___ Anatomical forceps
Special holding forceps
Temporal Bone Dissection - The Zurich Guidelines
81b
8"
8"
0.6 mm diamond burr
f---=O~/ } , mm
3mm
Shaft without Shoe
Nearly equal functional results have been obtained by placing the shaft of the FTTP without a shoe on the footplate. In this situation, however; a cartilage disc of 1 mm thickness obtained from the tragus or from the conchal cartilage must be used for stabilization. The cartilage disc has to fit tightly within the oval window niche. The technique used for the harvesting and preparation of the cartilage disc is shown in Figs. 81 a-g .
When the stapes arch is intact, the F II P is a/so used without a shoe. In this case, the stabilization is achieved by wedging small pieces of cartilage (from the tragus or concha) between the wall of the oval window niche and the prosthesis (Fig . SOc).
Temporal
E.2.2 F
General
This tech stapes a another t has farlec malleus r at an inle
First Sla
A piece endaural pedehan. diameter is introcll two sma handle, 9
The perie duced UI
and IS ar clock (r~ cus. The graft bet nameala! oval wine
Second :
The secc if no Slgr nameala' implantec various 9 SIS. Only superior excessivl desired I (using m, (fixed or I
The Titan duced O. the vesll usingsm stapedot, pledgels. glue (see
,
•
•
Temporal Bone Dissection - The Zurich Guidelines
E.2.2 Fisch Titanium Neo-Malleus
General Considerations
This technique is utilized In absence of malleus, incus and stapes arch, when the stapes footplate is fixed or when another type of total reconstruction of the ossicular chain has failed to improve the function of a mobile stapes. Neomalleus reconstruction is usually performed In two stages at an interval of three to six months,
First Stage
A piece of tragal perichondrium is obtained through the endaural approach (Figs. 61 a--c). A rectangular piece of perichondrium is cut slightly longer than the supero-inferior diameter of the drum. The 5 mm long titanium neo-malleus is introduced over the lateral surface of the graft through two small incisions (a No. 11 blade with rounded scalpel handle, graft on glass platform IS used) (Figs. 82 a, b).
The perichondrium with the attached neo-malleus is introduced under the partially elevated tympanic membrane and is anchored inferiorly through the gap created at 6 0' clock (right side) between the tympanic annulus and SUlcus. The perichondrium will rest superiorly as an overlayed graft between the superior canal wall and the tympaoomeatal flap. The titanium neo-mal/eus is aligned over the oval window (Fig. 82c).
Second Stage
The second stage is performed three to six months later if no signs of tubal dysfuction have appeared. The tymparlOmeatal flap is elevated and the superior end of the implanted neo-malleus is identified. The neo-malleus has various grooves for fixation of the loop of a stapes prosthesis. Only one of these indentations and not the complete superior end (as shown in the picture) is exposed to avoid excessive movement and 10 keep Ihe neo-malleus in the desired position. A 0.5 mm stapedotomy is performed (using manual perforators or a laser) in the center of the (fixed or mobile) footplate (Fig. 83 a).
The Titanium Stapes Prosthesis is brought into place. introduced 0.5 mm from the lateral surface of the footplate in the vestibule, and crimped on the titanium neo-malleus using smooth small straight alligator forceps (Fig. 83 b). The stapedotomy hole is sealed with three connective tissue pledgets, venous blood from the cubital vein, and fibrin glue (see Stapedotomy Figs. 51 a-c, page 27).
82.
820
82,
83b
Stapes only (Ii_ad or mobile)
41
42
Supra tubal cells
Supra· Jabynnth lne
cells
I Retro-
I
84
•
F Additional Temporal Bone Dissection
General Considerations
Eustachian tube
. Pericarolld celts
Internal carotid ar1ery
~-
Retrolacial cells
Retrosigmoid cells
Additional temporal bone dissections may be carried out at the end of the procedure. They represent a transition from temporal bone to lateral skull base surgery.
In the authors' opinion, these dissections belong within the curriculum of a modern otologist. who in fact should not remain a middle ear surgeon, but become a temporal bone surgeon.
F.1 Subtotal Petrosectomy (SP)
The principle of SP is "the complete elimination of the pneumatic middle ear cleft associated with the permanent occlusion of the isthmus of the eustachian tube W
• The cavity may be left open or be obliterated (with pedicled muscle flaps or free abdominal fat grafts). In the latter case, the EAC is closed in two layers as a blind sack.
There are two types of subtotal petrosectomy, one with OfesecvatlQQ the other with removal of the otic capsule (For more details see: "Microsurgery of the Skull Baseft
U. Fisch and D. Mattox, Georg Thieme Stuttgart New York 1988).
F.1.1 Subtotal Petrosectomy with Preservation of the Otic Capsule
General Considerations
This operation is is per10rmed to remove extensive tempo~ ral bone cholesteatomas, adenomas, extensive facia l nerve neuromas, angiomas and Class B paragangliomas. It is also used to seal congenital CSF leaks and Ihose of a
Temporal Bone Dissection - The Zurich Guidelines
Lateral semiCircular
"'"'" Supenor
semiCircular canal
85
GeniCulate gangioo
Internal carot id .rt"Y
Jugular bulb
Posterior semicircular
canal
traumatic nature (e.g ., following transverse fractures of the temporal bone). to introduce CI in sclerotic temporal bones, or when there is a meningitiS risk due to a possible CSF leak.
Exenteration of Pneumatic Cell Trac ts
The cell tracts of the middle ear cleft (Fig . 84) are exenterated in the follOWing order: retrosigmoid, retrofacial. retro~ labynnthine, supralabynnthine, supratubal. infralabyrinthine and pencarotld.
Most of these cellular tracts have been dealt with when per10rming an open MET.
In fact. an open~cavlty procedure performed according to the authors' surgical principles is a ~subtotal petrosecto~ my," with the exception of the infralabyn'nthine and peri~ carotid cells that are left intact.
Surgical site following exenteration of pneumatic cell tracts and preservation of the otic capsule
The pneumatic cell tracts of the temporal bone (with the exception of the apical) are removed (Fig. 85). To make sure that no cells are left behind , the jugular bulb and the vertical Intra temporal carotid artery are skeletonized.
The tympanic segment of the facial nerve is also skele~ tonized until the geniculate ganglion and the greater superficial petrosal nefVe are identified. Note that the labyrinthine segment of the faciat nerve is medial to and covered by its tympanic segment. and that the proximal tympanic segment and the geniculate ganglion form a bor~ der between the supratubal and supra labyrinthine recess~ es. The otic capsule and, therefore, inner ear function are preserved.
Pericarotid cells and obliteration of the eustachian tube
The vertical segment of the intratemporat carotid artery (ICA) is exposed to the bend indicating the beginning of the horizontal segment Note that the isthmus of the eustachi~ an tube is below and anterior to the ICA. The semicanal of the tensor tympani muscle covers part of the posterior aspect of the horizontal segment of the ICA. Remember that the ICA may be dehiscent along the medial wall of the
Tempor
prolymp< can exle may reql pericarot eustachi;
F.1.2 ~
F
General
The otic situated (e.g., SUI= teatomas 2,Di 1-2) part of II' associatE with rem approacl" Hilselbert base, Arc removal c nerve, Ie. details Of
sule, see Thieme ::: with rem< fore, reql
Remova
The sem rinthine a
The tym~ must be the medi~
the sup labyrinthi anterior a auditory canal is (Fig. 88).
Temporal Bone Dissection - The Zurich Guidelines
protympanum (Fig. 86). The anterocarotid pneumatic cells can extend into the pyramid apex, and their exenteration may require precise work with a diamond burr. When all pericarotid cells are exenterated, the isthmus of the eustachian tube is ready for obliteration with bone wax.
F.1.2 Subtotal Petrosectomy with Removal of the Otic Capsule
General Considerations
The otic capsule is removed to gain access to lesions situated along the medial aspect of the inner ear spaces (e.g., supralabyrinthine and infralabyrinthine-apical cholesteatomas, and temporal paragangliomas class C3-4 Del-2,Oi 1-2). The SP with removal of the otic capsula is also part of the transotic approach used for acoustic neuromas associated with a total loss of hearing. Remember that SP with removal of the otic capsula is not a transcoch/ear approach. The transcochlear approach (House WF, Hitselberger WE: The transcochlear approach to the skull base, Arch Otolaryngol 1976, 102: 334-342) coosists of the removal of the cochlea and posterior rerouting of the facial nerve, leaving the middle ear and fAG intact. (For more details 00 the SP with and without removal of the otic capsule, see Fisch U. Mattox D: Microsurgery of the Skull Base, Thieme Stuttgart and New York 1988). Lesioos requiring SP With removal of the ollc capsula involve the dura and, therefore, require obliteration of the pneumatic middle ear cleft.
Removal of the Posterior Otic Capsula (Labyrinth)
The semicircular canals are removed as in a trans/abyrinthine approach (Fi9 . 87).
The tympanic and labyrinthine segments of the facial nelVe must be watched. Removal of the cochlea continues until the medial wall of the vestibule, the posterior ampullary and the superior ampullary nelVe become visible. The labyrinthine segment of the facial nelVe is identified 2 mm anterior and 2 mm lateral to the superior edge of the internal auditory canal. The posterior wall of the internal auditory canal is skeletonized to the porus acousticus internus (Fig. 88).
Isthmus of Eustachian tube
86
Semlcanal of the tensor tympani m.
•
Oehiscent internal carotid artery
GenICulum of facial nerve
Supralabyrinthlr"18 ...,'"
Labynnlhlr"18 _ segment ...
01 facial nerve
87
Supratubal recess
Tympanic segment of facial nerve
43
44
Medial wall of vesllbule
Labyrinthine ,..menl
ollacial nerve
..
Internal auditory
canal
Internal audltOfY _I
Middle cranial
fossa dura
89
•
Petrosal nerve
Apical turn of cochlea
Middle turn of cochlea
Basal turn of cochlea
Posterior ampulla!)' nerve
Posterior fossa dura
Horizontal segment of ICA
Isthmus of Eustachian tube
VertiCal segment of ICA
Carotid foramen
Jugular bulb
Temporal Bone Dissection - The Zurich Guidelines
Removal of the Anterior Otic Capsula (Cochlea)
Sketetonize the mastoid segment of the facial nerve and the jugular bulb. Follow the lugular bulb as far as possible medial to the facial nerve toward the round window niche. Remove the bone covering the basal, middle and apical turn of the cochlea (the apical turn may be covered by the semicanal of the tensor tympani muscle) working anterior to the facial nerve (Fig. 68). Skeletonize the inferior and anterior walls of the internal auditory canal until you reach the anterior porus. Note that the internal auditory canal is situated deep and antenor to the skeletonized tympanic and mastoid facial nerve.
Expose the posterior fossa dura between the internal auditory canal, superior petrosal sinus (medial to the semicanal of the tensor tympani muscle), vertical carotid artery, and jugu lar bulb (Fig . 89). Opening this dura would lead in the anterior cerebello-pontine angle. This is what is done in the transotic approach. which is the only approach permitting the surgeon to first separate the intracranial segment of the facial nerve from the anterior pole of the tumor.
Final surgical site of SP with removal of the otic capsula
The complete medial wall of the temporal bone is exposed between Sigmoid sinus, superior petrosal sinus (separating dura of the middle and posterior cranial fossa), internal carotid artery and Jugular bulb. The cell tracts located medial to the otic capsula and extending toward Ihe pyramid apex have been completely exenterated (Fig 89).
P,,""o' G Suggested Reading ampulla!), (Singular) nerve
/"-..1' Posterior fossa dura
Sigmoid sinus
The fo llowing books and papers contain detailed information on the microsurgical techniques presented in this manual:
Books
U. FISCH in collaboration with J. MAY: Tympanoplasty. Mastoidectomy. and Stapes Surgery. (1" edition, 1994, Cl Georg Thieme Stuttgart - New York).
U. FISCH, J. MAY, 1. LINDER: Tympanoplasty, Mastoidectomy, and Stapes Surgery. (2"" edition, forthcoming 2006; approx. 320 pp, 36 tables, approx. 155 illustrations, hardcover. ISBN 158890167x I 3t3t37702x; C Georg Thieme Stuttgart - New York).
A. POSADA: Spanish translation of Tympanoplasty, Mastoidectomy and Stapes Surgery 1998
A. POSADA: Spanish translation of the Course Book of the Fisch International Microsurgery Foundation. 2002
U. FISCH, D. MATIOX: Microsurgery of the Skull Base, 1988 10 Georg Thieme Stuttgart - New York, 2000 © Thieme Classic Edition
R. POSADA: Spanish edition of Microsurgery of the Skull Base 1998
Tempora
Papers
U. FISC Lateral : LaryngOl:
HOUSE approacl 342, 197
FISCH U in Rev; Neurolol
HUBER , Oamagir. 22:311-
NANOAF The Ar Otosclen
KWOK f Surgery: the Lon~ and OiffE 295, 200
HUBER FISCH I Diagnosi Surgery. 348- 35
FISCH U L-shapel the Ossie 2004
H.1 f I
H.2 f 1 ,
Temporal Bone Dissection - The Zurich Guidelines
Papers
U. FISCH. PH. CHANG, TH. LINDER: Meatoplasty for lateral Stenosis of the External Auditory Canal, The laryngoscope 112: 1310-1314, 2002
HOUSE WF, HITSELBERGER WE: The transcochlear approach to the skull base, Arch Ololaryngol: 102: 334-342,1976
FISCH U., OEZBILEN G.A. , A. HUBER: Malleostapedotomy in Revision Surgery for Otosclerosis, Otology & Neurotology, 22:776-785, 2001
HUBER A. , LINDER T. and FISCH U.: Is the Er: Yag Laser Damaging to Inner Ear Function?, Otology & Neurotology, 22: 311-315, 2001
NANDAPALAN V., POLLAK A., LANGNER A. and FISCH U.: The Anterior and Superior Malleal Ligaments in Otosclerosis, Otology & Nerotology, 23: 854 - 861, 2002
KWOK P. , FISCH U., STRUTZ J . and MAY J.: Stapes Surgery: How Precisely Do Different Prostheses Attach to the Long Process of the Incus with Different Instruments and Different Surgeons?, Otology & Nerotology, 23: 289-295,2002
HUBER A., KOIKE T., NANDAPALAN V., WADA H. and FISCH U.: Fixation of the Anterior Mallear Ligament: Diagnosis and Consequence for Hearing Results in Stapes Surgery, Annals of Otology, Rhinology & Laryngology, 112: 348 - 355, 2003
FISCH U., MAY J., LINDER TH . and NAUMANN I.C.: A New L-shaped Titanium Prosthesis for Total Reconst ruction of the Ossicular Chain, Otology & Neurotology, 25: 891 - 902, 2004
H Prostheses and Instruments
H.1 FISCH Titanium Middle Ear Prostheses
H.2 FISCH Special Instruments for Tympanoplasty, Mastoidectomy and Stapedotomy -
45
46
FISCH Special Instruments for Tympanoplasty, Mastoidectomy and Stapedotomy
Temporal Bone Dissection - The Zurich Guidelines Tempora
CD 2202
@ 2196
@ 2197
@ 792C
® 2134
@ 5353 CD 2080 ® 2080
® 2118
® 2145
® 7933
@ 2140
@ 2130
@ 4775 @ 2240
@ 2047
® 2047 @ 2047
® 2047
® 2043
@ 2043
@ 2042
@ 2261
@ 2261
® 2263
@ 2268
@ 2254
@ 2254
@ 2254
® 2254
@ 2252
@ 2252
@ 2252
@ 2252
® 2265
® 2265
® 2265
® 224E @ 224e
@ 2266
@ 226'
Temporal Bone Dissection ~ The Zurich Guidelines 47
CD 220213 FISCH Endaural Retractor @ 226605 FISCH Manual Perforator, 0.5 mm
@ 219613 Curved Mastoid Retractor @ 226606 FISCH Manual Perforator, 0.6 mm (BELLUCCI), length 13 cm @ 221 111 FISCH Small Straight Alligator Forceps,
(j) 219717 B FISCH Articulated Retroauricular smooth, (crimping forceps for stapes Retractor prosthesis)
@ 792003 Strong Curved Scissors (MAYO) @ 221 11 0 FISCH Large Straight Alligator Forceps,
® 213410 FISCH Small Tympanoplasty Scissors smooth (crimping forceps for stapes prosthesis) @ 535312 Small Curved Clamp (Mosquito)
@ 221201 FISCH Small Straight Alligator Forceps, CD 208000 Scalpel Handle No. 3, length 12.5 cm serrated
® 208001 FISCH Round Scalpel Handle, @ 221 100 Large Straight Alligator Forceps, length 14 cm
serrated (HARTMANN) ® 211804 FISCH Dual Purpose Scalpel Handle,
@ 221406 F Ultra Fine Biopsy Forceps length 16 cm (FISCH, 8 cm, 0.6 mm)
~ 214500 F Jeweler Forceps, soft spring 0 221409 Small Biopsy Forceps
® 793303 F Small Tympanoplasty Forceps (VoJULLSTEIN, 8 cm, 0.9 mm) (Tissue Forceps), toothed
@ 162020 Large Biopsy Forceps @ 214000 F Small Tympanoplasty Forceps (HARTMANN, 2.0 mm)
serrated ® 222606 FISCH-BELLUCCI Ultra Fine
@ 213011 FISCH Mastoid Raspatory Tympanoplasty Micro Scissors @ 477500 KEY-Raspatory (curved FREER) @ 222603 FISCH Small Tympanoplasty Micro @ 224003 FISCH Double End Sharp Curette Scissors
(HOUSE, medium) @ 222601 Large Tympanoplasty Micro Scissors <ill 204729 FISCH Suction Tube, 1.2 mm (FISCH-BELLUCCI)
® 204730 FISCH Suction Tube, 1.5 mm ~ 222710 FISCH Crurotomy Scissors, curved right @ 204732 FISCH Suction Tube, 2.0 mm ® 222720 FISCH Crurotomy Scissors, curved left
® 204733 FISCH Suction Tube, 2.2 mm ® 222801 FISCH Malleus Nipper ~ 204352 Suction Cannula, angular, ® 227525 FISCH Cutting Block for Titanium
size 0.7 mm, 7.0 cm Prostheses @ 204354 Suction Cannula, angular. ® 227527 Crimping Forceps.
size 1.0 mm, 7.0 cm for FISCH Titanium Incus Prosthesis
@ 204250 FISCH Suction Adaptor 0 227530 Holding Forceps,
@ 226101 FISCH Micro Raspatory, curved right for FISCH Titanium Incus Prosthesis
@ 227532 FISCH Micro Hook, for transporting and @ 226102 FISCH Micro Raspatory, curved left positioning the FISCH Titanium Ineus @ 226301 FISCH Tenotome Prosthesis
@ 226810 Joint Knife, 45°, round 0 227528 Scissors, for FISCH Titanium Total Prosthesis
@ 225405 Pick 45°,16 em, 0.5 mm @ 227526 Holding Forceps, @ 225410 Pick 45°, 16 cm, 1.0 mm for FISCH Titanium Total Prosthesis
@ 225415 Pick 45°, 16 cm, 1.5 mm ~ 227534 Diamond Burr, 1.4 mm, 7 cm for FISCH Titanium Incus Prosthesis
® 225425 Pick 45°, 16 em, 2.5 mm 8 843016 Bipolar Coagulating Forceps, angular,
@ 225205 Pick 90°, 16 em, 0.5 mm tip 0.4 mm, insulated, length 16 cm
@ 225210 Pick 90°, 16 cm, 1.0 mm @ 843016 F Bipolar Coagulating Forceps, angular, tip 0.2 mm, insulated handle, non-insulat-
@ 225215 Pick 90°,16 cm, 1.5 mm ad from angle to tip, length 16 em @ 225220 Pick 90°,16 cm, 2.0 mm ® 842016 F Bipolar Coagulating Forceps, @ 226514 FISCH Measuring Caliper, 0.4 mm angled tip, pointed , tip 0.4 mm, insulated,
length 16 cm (not illustrated) ® 226516 FISCH Measuring Caliper, 0.6 mm
@ 516013 Needle Holder, tungsten carbide @ 226501 FISCH Measuring Rod Inserts, length 13 cm
@ 224812 FISCH Anterior Footplate Elevator @ 227900 SHEA Vein Press, 13 cm @ 224813 FISCH Posterior Footplate Elevator @ 231009 FISCH Glass Cutting Board
® 226600 FISCH Manual Perforator, 0.3 mm ® 239728 Metal Tray, for 20 straight ear micro
@ 226604 FISCH Manual Perforator, 0.4 mm instruments (not illustrated)
48
220213
CD 220213
<V 219613
@ 219717 B
Temporal Bone Dissection - The Zurich Guidelines
219613 219717
FISCH Endaural Retrac tor
Curved Mastoid Retractor (BELLUCCI), length 13 em
FISCH Articulated Retroauricular Retrac tor
792003 213410 535312
o 792003
® 213410
@ 535312
Strong Curved Scissors (MAYO). length 16 em
FISCH Small Tympanoplasty Scissors
Small Curved Clamp (Mosquito)
Temporal
Temporal Bone Dissection - The Zurich Guidelines
o 208000
® 208001
® 211804
@l 214500 F
® 793303 F
@ 214000 F
® ®
I
208000 208001 211804
Scalpel Handle No, 3, length 12.5 cm
FISCH Round Scalpel Handle, length 14 cm
FISCH Dual Purpose Scalpel Handle, length 16 cm
II I
214500 F
®
793303 F
@
214000 F
Jeweler Forceps, pointed, soft spring
Small Tympanopla sty Forceps (Tissue Forceps), toothed
Small Tympanoplasty Forceps, serrated
49
50
, i , ,
213011 477500
@ 213011
@ 477500
@ 224003
@ 204729
® 204730
® 204732
@ 204733
Q!) 204352
@ 204354 @ 204250
3 226101
@ 226102
Temporal Bone Dissection - The Zurich Guidelines
@-@ @-@ @
224003 204729 - 204733 204352 204354
FISCH Mastoid Raspatory, 10 mm
KEY·Raspatory (curved FREER). 18 mm
204250
FISCH Double End Sharp Curette (HOUSE, medium)
FISCH Suction Tube, 1.2 mm
Same, 1.5 mm Same, 2.0 mm Same, 2.2 mm
Suction Cannula, angular, size 0.7 mm, 7.0 em
Same, size 1.0 mm. 7.0 em FISCH Suction Adaptor
FISCH Micro Raspatory, 16 em, curved right
FISCH M icro Raspatory, 16 em, curved left
226101
226102
226101-226102
Tempora
Temporal Bone Dissection - The Zuneh GUidelines 51
@-@
, ,
226301 226810 225405 - 225425 225205 - 225220
@ 226301 FISCH Teno tome, 16 cm
@ 226810 Joint Knife, 45". round
@ 225405 Piek 45°, 16 em. 0.5 mm @ 225410 Piek 45°, , 6 em. 1.0 mm
@ 225415 Piek 45°, 16 em. 1.5 mm @ 225425 Pick 45°,16 em, 2.5 mm
@ 225205 Piek 90°,1 6 em, 0.5 mm
@ 225210 Pick 90", 16 em, ' .0 mm
@ 225215 Piek90°, 16em, 1.5mm
@ 225220 Pick 90",1 6 em, 2.0 mm
52
226514 226516
226501
® 226514 @ 226516
® 226501
@ 224812
@ 224813
~ 226600 @ 226604
@ 226605
0 226606
Temporal Bone Dissection - The Zurich Guidelines
\
224812 224813
FISCH Measuring Caliper, 0.4 mm
Same, 0.6 mm
FISCH Measuring Rod, 16.5 em
226600 - 226606
FISCH Anterior Footplate Elevator, curved upward 90"
FISCH Posterior Footplate Elevator, curved downward 90"
FISCH Manual Perforator, 0.3 mm
Same, 0.4 mm
Same, 0.5 mm Same, 0.6 mm
Tempora
-
,
,
--
Temporal Bone Dissection - The Zurich GUidelines
@ 221111
® 221 11 0
@ 221201
@ 221100
@ 221406 F
® 221409
@ 162020
221111
221201
221406 F 221409
=--~ .. -
FISCH Small Straight Alligator Forceps, smooth, (crimping forceps for stapes prosthesis)
FISCH large Straight Alligator Forceps, smooth (crimping forceps for stapes prosthesis)
FISCH Small Straight Alligator Forceps, serrated
large Straight Alligator Forceps, serrated (HARTMANN), 0.4 x 3.5 mm
Ultra Fine Biopsy Forceps (FISCH. Bern, 0.6 mm)
Small Biopsy Forceps (WULlSTEIN. 0.9 mm)
large Biopsy Forceps (HARTMANN, 2.0 mm)
53
221110
221100
162020
54
®"'"'--222606
222603
® 222606
~ 222603
~ 222601
S 222710 ~ 222720
S 222801
@ 227525
Temporal Bone Dissection - The Zurich Guidelines
222603 222606
222601
•
222710
@ _.-222720
222710 222720
222801
FISCH -BELLUCCI Ultra Fine Tympanoplasty Micro Scissors
FISCH Small Tympanoplasty Micro Scissors
large Tympanoplasty Micro Scissors (FISCH-BELLUCCI)
FISCH Crurotomy Scissors, curved right
Same, curved left
FISCH Malleus Nipper
FISCH Cutting Block, lor Titanium Prostheses
•
•
227525
Tempor
227534
Temporal Bone DIssection - The Zurich GUIdelines
227527
@ 227527
@ 227530
0 227532
@ 227528
@ 227526
227534 843016
0 227534
S 843016
0 843016 F
0 842016 F
e 516013
@ 227900
0 231009
•
227530 227532 227528
Crimping Forceps, for FISCH Titanium Incus Prosthesis
Holding Forceps, for FISCH Titanium Incus Prosthesis
FISCH Micro Hook, for transporting and positionIng the FISCH Titanium Incus Prosthesis
Scissors, for FISCH Titanium Total Prosthesiss
Holding Forceps, for FISCH Titanium Total Prosthesis
843016 F 842016 F 516013
Diamond Burr, 1.4 mm, 7 cm, for FISCH Titanium Incus Prosthesis
Bipolar Coagulating Forceps, angular, tip 0.4 mm, insulated , length 16 cm Bipolar Coagulating Forceps, angular, 0.2 mm, insulated handle, non-insulated from angle to tIp, length 16 cm
Bipolar Coagulating Forceps, angled t ip , pointed, t ip 0.4 mm, insulated, length 16 cm
Needle Holder, tungsten carbide inserts, length 13 em
SHEA Vein Press, 13 cm
FISCH Glass Cutting Board
55
227526
227900
.
231009
56
FISCH TITANIUM Middle Ear Prostheses
227510
227511
227512
227520
1. 1.
FISCH TITANIUM Stapes Piston, short distance between loop and cylinder, 7.0 x diam. 0.4 mm, short size, sterile
FISCH TITANIUM Stapes Piston, medium distance between loop and cylinder, dia. 8.5 x dlam. 0.4 mm, normal size, sterile
FISCH TITANIUM Stapes Piston , long distance between loop and cylinder, dia. 10.0 x diam. 0.4 mm. long size, sterile
FISCH TITANIUM To tal Prosthesis , wllh foot, 10.0 x diam. 0.6 mm, sterile
Temporal Bone Dissection - The Zurich Guidelines
227515
227516
227517
227522
FISCH TITANIUM Incus Prosthes is , 3.0 mm (1.31 diam. 2.0 mm), normal size, sterile
FISCH TITANIUM Incus Prosthesis. 4.0 mm (1.31 dlam. 2.0 mm), long size, sterile
FISCH TITANIUM Incus Prosthesis , 5.0 mm (1.31 diam. 2.0 mm), extra long size, sterile
FISCH TITANIUM Neom alleus Prosthesis, 5.0 x diam. 1.1 mm, sterile
Tempo
Meta
Temporal Bone Dissection - The Zurich Guidelines
Metal Tray for Sterilizing and Storage of Ear Instruments
239728 Metal Tray, for sterilizing and storage of ear instruments, perforated, bottom part with holder for 20 straight ear micro instruments with octagonal handle type 223300, lid with silicone bridges. external dimensions (w xd x hl: 285 x 175 x 36 mm
57
58 Temporal Bone Dissection - The Zurich Guidelines
UNIDRIVE ENT The multifunctional unit for otorhinolaryngology
a
Special Features and Specifications
One unit - six functions: - Shaver system for surgery of the paranasal sinuses and anterior skull base - INTRA Drill - Sinus Burr - Micro Saw - STAMMBERGER-SACHSE Intranasal Drill - Dermatome
Two outputs: Two motor outputs enable to connect two motors simultaneously. For example an intranasal drill and a paranasal sinus shaver or two INTRA drill hand pieces may be connected in parallel.
New integrated irrigation and coolant pump: Absolutely homogenous, micro-processor controlled irrigation rate throughout the entire irrigation range. Quick and easy connection of the tubing set.
Touch Screen: Straightforward function selection via touch screen. The unit stores the parameter values of the function selected during the last operation session.
Optimized user control via touch screen
Operating elements are simple and clear to read due to color display
Irrigator rod included
• Continuously adjustable revolution range
• Maximum number of revolutions and motor torque: The set parameters are maintained throughout the drilling procedure by the microprocessor controlled electronic motor.
• Maximum number of revolutions can be preset
• ,.. . model with connections to the KARL STORZ Communication Bus System
Tempora
UNIDI Specific
Temporal Bone Dissection - The Zurich Guidelines
UNIDRIVP ENT Specifications
Shaver Mode Operat ion mode: Maximum revolutions (min '):
Sinus BUrT Mode Operation mode: Maximum revolutions (min '):
Drilling mode Operation mode: Maximum revolut ions (min 'I:
Micro saws mode Maximum revolut ions (min 'I:
Intranasal Drill mode
oscillating in conjunctiOn with Micro Shaver Handpiece 40 71 10 35 in conjunction with Paranasal Sinus Shaver Handpiece 40 711039 in conjunction With OriliCut-X Shaver Handpiece 40 7110 40
rotating in conjunction with OrillCul-X Shaver Handpiece 40 711 0 40
counter clockwise or clockwise in conjunction wilh EC micro motor 20 711032
in conjunction wilh EC micro motor 20 711032
Maximum revolut ions (min '): in conjunction wi th EC micro motor 20 71 1 0 32
Dermatome mode Maximum revolut ions (min '): in conjunction with EC micro motor 20 711 0 32
Touch screen:
Power supply:
Dimensions (w x h x d):
Weight:
Two outputs for parallel connection of two motors
Integrated irrigation pump
Flow:
Available languages:
20 711032
6.4"/300 cd/m'
100 - 120, 230 - 240 VAC, 50/60 Hz
304 x 164 x 263 mm
6,1 kg
15 - 125 ml/min.
English, French, German, Spanish, Iialian, Portuguese, Greek, Turkish Certified to: lEG 601-1 GE, according to MOD
20 711 0 72
Spec ial features of the high performance EC micro motor with INTRA coupling:
• Self-cooling , brushless high • INTRA coupling enables a wide performance EC micro motor variety of appl ications
• Smallest possible dimensions • Maximum torque 4 Ncm
• Autoclavable • Number of revolutions can be
• Detachable connecting cable continuously adjusted from o - 40,000 rev./mln.
3.000 7.000 7.000
12.000
40.000
20.000
60,000
8.000
59
60 Temporal Bone Dissection - The Zurich Guidelines
UNIDRIVE ENT System Configurations recommended by KARL STORZ
B 00
20 711620·'
40 711601-1 UNIDRIVE ENT
consisting o f:
20 711620-1 UNIDRIVE ENT with KARL STORZ-SGB • 100 - 120, 230 - 240 VAC, 50160 Hz
400 A Mains Cord
20 012630 Two-Pedal Footswitch, two-stage, with proportional function
20 711640 20 711621
20 0901 70
Silicone Tubing Set, for irrigation, sieriiizable
Clip-Set, for use with tubing set 20 71 1640
SGB Connecting Cable, length lOa em
Accessories:
20 711032 20 711072
280052 B
260052 C
mtp·
High Performance EC Micro M otor
Connecting Cable, to connect EC molor 20 7110 32 to control unit
Universal Sprayer, 0.5 I bottle, for use with 280052 C, - HAZARDOUS GOODS - UN 1950
Spray Diffuser, for use with 280052 B
Set of Tubes, for single patient use
*) This product is marketed by mtp. For additional information, please apply to:
~ mtp medical technical promotion gmbh, p.o. box 4529,78510 Tuttlingen, Germany Email: [email protected]
Tempora
UNIDI System
PA
Temporal Bone Dissection - The Zurich Guidelines
UNIDRIVE ENT System Components
U NIT SIDE
PATIENT SIDE
INTRA Drill tl~l l ce
-
Two·_al Foonw+tcll
-
•
00
20 7110:12 20 1110n
1
2$4000 - 2$4300
61
Silic:onor TuI>Ing Sel
I
I I 20 711640
62 Temporal Bone Dissection - The Zurich Guidelines
INTRA Drill Handpiece
Special Features:
• Tool-free c losing and opening of the drill • light construction
• Right/left rotation • Operates with little vibrations
• Max. rotating speed up to 40,000 min ' • low maintenance , easy c leaning
• Detachable irrigation channels
252475
252495
252490
280052
• Safe grip
252475
INTRA Drill Handpiece, angled , 12.5 em, for use with straight shaft burrs, transmission 1:1 (40,000 rpm)
252495
INTRA Orill Handpiece, straight, long shape, 10.4 em, for use with straight shaft burrs, transmission 1: 1 (40,000 rpm)
252490
INTRA Drill Handpiece, st raight, 8.7 em, for use with straight shaft burrs, transmission 1:1 (40,000 rpm)
280052
Universal Spray, combination cleaner and lubricant, for INTRA Drill Handpiece and EC motors, package of 6 sprayers 280052 Band 1 spray d iffuser 280052 C - HAZARDOUS GOOD - UN 1950
Tempora
Burrs Straight
Temporal Bone Dissection - The Zurich Guidelines
Burrs Straight Shaft Burrs, length 7 em
Size Dia. mm
006 0.6
007 0.7
008 0.8
010 1.0
014 1.4
018 1.8
023 2.3
027 2.7
031 3.1
035 3.5
040 4.0
045 4.5
050 5.0
060 6.0
070 7.0
260000
261000
262000
262200
280030
7.0 em
Standard Tungsten Transverse Diamond Carbide Tungst.Carb.
260006 261006 262006
260007 262007
260008 261008 262008
260010 261010 262010
260014 261014 261114 262014
260018 261018 262018
260023 261023 261123 262023
260027 261027 262027
260031 261031 261131 262031
260035 261035 262035
260040 261040 261140 262040
260045 261045 262045
260050 261050 261150 262050
260060 261060 261160 262060
260070 261070 262070
Standard Straight Shaft Burrs, length 7 em, sizes 006 - 070, set of 15
Tungsten Carbide Shaft Burrs, length 7 em, sizes 006 - 070, set of 14
Diamond coarse
262223
262227
262231
262235
262240
262245
262250
262260
262270
Diamond Straight Shaft Burrs, with smooth shaft, length 7 em, sizes 006 - 070, set of 15
Rapid Diamond Straight Shaft Burrs, with coarse diamond coating for precise drilling and abrasion by light hand pressure. generating minimal heat. length 7 em, sizes 023 - 070, set of 9
Rac k, for 36 straight shaft burrs with a length of 7 em, can be folded out, sterilizable. 22 x 1 1.5 x 2 em
63
64
Burrs Straight Shaft Burrs, length 5.7 em
0
(0
0
0
0
0 0 0 0 0 0
Straight Shaft Burrs oblong, length 1 em
Size
014
018
023
027
031
035
040
045
050
060
070
649600 K
649700 K
649700 GK
Temporal Bone Dissection - The Zurich Guidelines
5.7 em
e= Dia. mm Standard Diamond
Diamond coarse
1.4 649614 K 649714 K
1.8 649618 K 649718 K
2.3 649623 K 649723K 649723 GK
2.7 649627 K 649727 K 649727 GK
3.1 649631 K 649731 K 649731 GK
3.5 649635 K 649735 K 649735 GK
4.0 649640 K 649740 K 649740 GK
4.5 649645 K 649745 K 649745 GK
5.0 649650 K 649750 K 649750 GK
6.0 649660 K 649760 K 649760 GK
7.0 649670 K 649770 K 649770 GK
Standard Straight Shaft Burrs, stainless steel. length 5.7 em, sizes 014 - 070, setofl1
Diamond Straight Shaft Burrs, stainless steel, length 5.7 em. sizes 014 - 070, set of 11
Rapid Diamond Straight Shaft Burr, stainless, with coarse diamond coating for precise drilling and grinding without applying pressure with minimal heat buildup. length 5.7 em, sizes 023 - 070, set of 9
265050 - 265070
Size Oia. mm Standard
050
060
070
5.0
6.0
7.0
265050
265060
265070
Tempora
Burrs
lINDEM length 7
Olamon length "I
Oiamon length;
Temporal Bone Dissection - The Zurich Guidelines
Burrs
LINDEMANN Conical, stainless, length 7 em
Diamond Straight Shaft Saw, length 7 em
Diamond Saw Drill, length 7 em
280090
Size Oia. mm Standard
018
021
023
1.8
2.1
2.3
263518
263521
263523
Size Dia. mm Standard
008
OlD
015
0.8
1.0
1.5
267008
267010
267015
Size Dia. mm Standard
008
OlD
015
0.8
1.0
1.5
280090
268008
268010
268015
269000
Hole Gauge, for burrs, stainless, autoclavable
65
66 Temporal Bone Dissection - The Zurich Guidelines Tempor
Burrs - Accessories Burrs
280010 Rack, with lid for 34 straight shaft burrs with 7 em shafts, sterilizable, 19.5x 9.5 x4 em
280080
280120
280030
280030 K
280080 280120
Brush, for cleaning burrs, sterilizable, package of 5
Temporal Bone Holder, bowl-shaped, with 3 fixat ion screws for tensioning the petrosal bone and with evacuation tube for irrigation liquid, incl. weight plate 280121 for stabilization of the bowl and rubber ring 8575 GKR for base to prevent sl ipping
280030
Rack, for 36 straight shaft burrs with a length of 7 em. can be folded Qut, sterilizable, 22 x 11.5 x 2 em
Metal bar, for fixation at rack 280030. to hold 18 burrs with a length of 7 em and 16 burrs with a length of 5.7 em, size 16 x 2.5 x 1 em
280030 K
-
Temporal Bone Dissection - The Zurich Guidelines
Burrs - Accessories
39552 A
39552 B
39552 A
• • • ' .. • : .. . . :
Including basket for small parts
Sterilizing and Storage Basket, provides safe storage of accessories for KARL STORZ drilling/grinding systems during cleaning and sterilization, includes basket for small parts, for use with rack 280030, rack not included
for storage of :
- Up to 6 drill handpieces - Connecting cable - EC micro motor - Small parts
Sterilizing and Storage Basket, provides safe storage of accessories for KARL STORZ drilling/grinding systems during cleaning and sterilization, Includes basket for small parts, for use with rack 280030, rack inc luded
for storage of:
- Up to 6 drill handpieces - Connecting cable - EC micro motor - Up to 36 drill bits and burrs - Small parts
67