Endoscopic Anatomy of Nose and PNS Final

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Endoscopic Anatomy Of Nose And Paranasal sinusesPresenter : Maj S RainaModerator: Lt Col R Datta

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Outline Evolution and historical background Brief Gross anatomy Endoscopic Anatomy

Diagnostic Surgical

Fly through Anatomy, relations, variations, applied

and surgical aspects

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Scope Important applied and surgical

endoscopic anatomy How it looks through the endoscope ! Omitting radiological, embryological

and external anatomy

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Evolution Endo’ – within ; ‘skopeein’– to see Optical device with lighting Used to look inside a body cavity, organ

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Evolution 1806 Philip Bozzini, Frankfurt made a

"Lichtleiter" (light conductor) illuminated by a candle

1853 Desormeaux added burning gas flame to it - “father of endoscopy”modified by Cruise and Andrews light source and mirror attached to the instrument.

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Evolution Lang Ebert's uretheroscope 1868 Wales endoscope 1868 Bruntons otoscope Endoscope and mirror combined,

light source separate

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Bruntons otoscope Wales endoscope

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Modern endoscopes Nitze-Leiter 1879, marks the second stage of

development German urologist ; developed Cystoscope ‘to light up a room one must carry the lamp

inside’. Used platinum wire light for illumination

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1945 – Karl Storz est his company 1951-1965 Harold Hopkins, fundamental

improvements made Solid glass rods with lenses in between,

providing excellent resolution with good contrast, a large visual field and perfect fidelity of colour

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Gross anatomy External Nose Nasal Septum Lateral Wall of Nose Paranasal Sinuses

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Septum

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Lateral wall INFERIOR TURBINATE

& MEATUS MIDDLE TURBINATE & MEATUS SUPERIOR TURBINATE & MEATUS SPHENOETHMOIDAL RECESS

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Paranasal sinuses

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Paranasal sinuses Late 19th century Emil Zukerkandl published

first detailed anatomic & pathologic description of PNS. “Father of modern sinus anatomy”.

Related to the regional anatomy of cranio-oro-facial region.

Varies from person to person and even side to side

“All but sphenoids develop from invagination from lateral nasal wall”

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Paranasal sinuses Air-filled pockets within the cranium which

communicate with the nasal cavity & lined with the same type of ciliated mucous membrane

Anterior Group: Frontal Maxillary Anterior ethmoid

Posterior Group: Posterior ethmoid Sphenoid

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Frontal sinus Pyramidal shaped air

cells Can be considered as

an ant ethmoidal air cell

Rudimentary at birth,first becomes distinct at 6-8 yrs.

Continuing pneumatisationinto the frontal bone formsthe frontal sinus

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Fully developed b/w 12 & 14 yrs in female and 16-18 yrs male

Separated by bony septum, develop independently and asymmetry between them is rule than exception.

Frontal recess-superior ascending part of first primary furrow

The roots of the confusing anatomy in the area of frontal recess (frontonasal duct) go back all the way to its embryonic development

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Maxillary sinus Largest and most

constant PNS First sinus to develop Appears slit like –In

fetal life Shape(round or

elongated to gradually pyramidal)

Further growth followsdevelopment of maxilla

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Ethmoid sinus Complex group of small cells(3-14) located

within the Ethmoid bone At birth Ethmoid sinus fluid filled During primary pneumatisation ethmoids

develop from dimple like depression on nasal mucosa. Deepen and become air cells

Other structures i.e turbinates/uncinate/ bulla are medial extension from lat nasal wall.

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Complex anatomy & intersubject variation

For simplification divided into series of parallel lamella First: Uncinate Second: Ethmoid bulla Third: Basal/Ground lamella

of MT Fourth : lamella of superior

Turbinate The lamellae are relatively

constant features between human subjects, making intraoperative recognition important

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Sphenoid sinus

Develops as an evagination from the sphenoethmoidal recess

Small cavity at birth Extensive variation in

Pneumatisation, asymmetry very common

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Outline Evolution and historical background Brief Gross anatomy Endoscopic Anatomy

Diagnostic Surgical

Fly through Anatomy, relations, variations, applied

and surgical aspects

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Diagnostic nasal endoscopy A careful and methodical diagnostic

endoscopy is the key.

Equipment

Procedure

Normal endoscopic findings

Anatomical variations

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Equipment Light source Cable Endoscope [0 - 30

degree] , [wide angle] , [2.7 - 4 mm]

Suction tubes [straight - curved]

Forceps [forward - upward]

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PositionEndoscopist Patient

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Passes in nasal endoscopyS No Scott

BrownStammberger

AP Singh Bradoo

First Pass Floor – Nasopharynx – Inf meatus

Second pass

Spheno ethmoidrecess

Spheno ethmoid recess, sup meatus

Spheno ethmoid recess, sup meatus

Spheno ethmoid recess, sup meatus

Third Pass Return into middle meatus

Ant to post direction

Ant to Post into middle meatus

Both ways

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1st Pass 0 or 30 degree scope passed gently along

the floor of nasal cavity b/w inf turbinate and septum without touching them.

Inferior meatus :NLD opening Floor of the nose, nasal septum Post nasal space, Roof of nasopharynx ET opening Mucus channels

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Endoscopic view

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Inferior turbinate Separate bone, inf

concha Irregular surface

with grooves for vs Maxillary process articulates with inf margin of

maxillary hiatus. Forms the med wall

of NLD

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Nasal septum & Floor Nasal septum and

the adjoining floor can be visualized while advancing the scope

Look for spurs, mucosal anomalies

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Nasopharynx Eustachian tube

opening can be visualised.The cartilaginous end protrudes in the nasopharynx. Torus tubaris and the fossa of Rosenmuller is seen

Dynamic study

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Inferior meatus Largest meatus

extending almost entire length, lateral to inf turbinate

Highest at jn of ant and mid 1/3

NLD opens just ant to highest point

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2nd Pass Careful and gentle

handling Scope advanced b/w

septum & post part of MT Moved upwards medial to

MT along roof of post choana & ant surface of sphenoid

ST and meatus seen Sphenoethmoidal recess

visualised,ostia 1-1.5cm above the roof of post choana

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Sphenoid Sinus ostia Ostia 1-1.5 cm above the

post end of choana, opens into the Sphenoethmoid recess

Least invasive access to sphenoid

Preferred route for Biopsy / sampling

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Middle turbinate 3 Parts Anterior third : saggital plane attached superiorly

to lateral lamella of cribriform plate Basal Lamella : coronal plane attached to lamina

papyracea (separates the ethmoids) Related to ethmoid bulla intimately or

seperated by lateral sinus Posterior third: attached to lamina papyracea or

lateral wall of nose (roof of middle meatus)

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Anatomic variations Concha bullosa:ballooned air cell enclosed

within, pneumatised Interlamellar cell of Grunwald: pneumatised

vertical lamella Paradoxically curved turbinate Bifid turbinate: ground lamella attached to

lat wall of maxillary sinus instead of lamina papyracea.

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Paradoxically curved MT, Bifid MT

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Concha bullosa

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Concha bullosa

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Spheno-ethmoid recess The recess lies med to sup turbinate and lat to

septum Bounded above by skull base, inf continuous

with post part of nasal cavity The ostia of sphenoid sinus opens 1-1.5cm above

roof of post choana Often hidden by view of sup turbinate Ostium shows variations in size and shape, being

circular, oval and sometimes pinpoint. Below the ostia is the mesh of bld vs forming the

Woodruff’s plexus. Septal br of sphenopalatine artery runs across the ant wall of sphenoid.

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Accessory Ostia Accessory ostia may be seen in the region

of ant fontanelle i.e. ant inf to ant end of uncinate process or in the region of post fontanelle i.e. above and behind the post end of uncinate process (most common)

Circular and easily seen unlike the natural ostia which is often hidden.

Incidence varies from 15-45 % with an average of 25%.

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Accessory ostia

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3rd Pass Examine the

contents of middle meatal region and osteomeatal complex

Scope advanced from ant to post. to view middle meatal contents

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Key anatomical features Osteo meatal Complex Uncinate Process Ethmoid bulla Lateral sinus Hiatus Semilunaris Infundibulum

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Uncinate process Thin sagittally oriented

bony leaflet Resembles a bent hook

or boomerang Convex anteroinf Overlies infundibulum Most imp surgical

landmark

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Variations in attachment

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Uncinate importance Risk of entering orbit due to proximity

to lamina papyracea Its medial end is strategical located

near the OMC Dynamics are such that any abnormal

growth or excess pneumatization of uncinate can narrow the outflow of sinuses

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Ethmoid bulla Ethmoid bulla is

largest and least variable air cell in the anterior Ethmoid complex lying medial to attachment of lamina Papyracea

Pneumatised in 70%

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Bulla ethmoidalis

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Attachments Lateral :Lamina Papyracea along entire length Posterior :Expand to vertical portion of basal lamella Superiorly :fuse with roof of ethmoid sinus(forms post wall of frontal recess). If it does not reach Ethmoid sinus space is lateral sinus

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When unpneumatized, appears as bony projection from the lamina papyracea, called as the torus lateralis.(apprx 8%)

3 variations Simple 47% single large cavity Compound 26% 2-3 compartments each

opens medially anterior to basal lamella

Complex 27% 2-3 compartments, one to hiatus semilunaris

above, rest ethmoid infundibulum

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Sinus lateralis Space designated by Gurnwald

(haitus semilunaris superior) Not constant feature Boundaries

Lateral: Lamina Papyracea Superior: Roof of ethmoid Posterior: Ground lamella Anterior & Inferior: Ethmoidal bulla

Reached through hiatus semilunaris medially between Ethmoid bulla & Middle turbinate

Localised disease may develop without involving bulla, difficult to diagnose endoscopically

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Hiatus semilunaris(Hiatus: Gap, Semilunaris: Cresent shape)

2D slit between post margin of uncinate and the anterior face of Ethmoid.

Hidden by overhanging middle turbinate

Forms doorway that leads to infundibulum

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Hiatus semilunaris

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Ethmoid infundibulum 3 dimensionsal funnel-shaped passage

through which the secretions from anterior ethmoid, maxillary sinus, and in some cases, the frontal sinus are channeled into the middle meatus.

Medially: Uncinate process Laterally: Lamina Papyracea Ethmoid bulla superiorly Opens into middle meatus through hiatus

semilunaris

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Osteomeatal complex The uncinate process,

the ethmoid infundibulum, anterior ethmoid cells,and ostia of the anterior ethmoid, maxillary, and frontal sinuses

Final common drainage pathway of ant gp of sinuses

Small amount of obstruction here leads to significant disease in the larger frontal and maxillary sinus

Functional area

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OUTLINE Evolution and historical background Brief Gross anatomy Endoscopic Anatomy

Diagnostic Surgical

Fly through Anatomy, relations, variations, applied

and surgical aspects

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Endoscopic Anatomy - Surgical Maxillary sinus ostia Agger nasi Lamina papyracea Ground lamella Roof of ethmoid and anterior ethmoid artery Posterior ethmoid cells Frontal sinus Sphenoid sinus Skull base

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Maxillary sinus ostium Anatomical entity of

utmost importance Can be elliptical,

rounded or oval Natural ostium is in ant

fontanelle Not visualised usually,

seen after uncinectomy 2-3 Accessory ostia

may open in post fontanelle

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Ostium Location in endoscopy

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Nasal fontanelles Area on the lateral nasal wall above the IT

in which no bone exists Max sinus & Middle meatus separated only

by fibrous periosteum The anterior fontanelle is inferior and

anterior to the uncinate process (inferolateral edge)

the posterior fontanelle is superior and posterior

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Applied aspects Damage to NLD in excessive ant widening

Ant extenision may damage branches of ant superior alveolar nerve (Branch of Infraorbital nerve)…altered dental sensation

If antrostomy extended too posterior inf meatal branch of sphenopalatine artrey is encountered

Main ostia of max sinus is very close to roof of max sinus so care to be taken in middle meatus antrostomy to avoid damage to roof of max sinus, possible penetration into orbit

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Haller cells Infraorbital

ethmoid air cells Best studied on ant

and post coronal CT images

Adhere to roof of maxillary sinus forming the lat wall of infundibulum

Incidence of 10-40%

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Agger nasi cells Ant most ant ethmoid air cells First prominent anatomical landmark

encountered in FESS Location: ant sup to insertion of ant 1/3 of MT

and ant to uncinate (sagittaly) Endoscopically seen as a ridge, prominence or

mound on lat wall Boundaries : ant- frontal process of maxilla

post- ethmoidal infundibulum sup- frontal recess and sinus inf med- uncinate process lat- nasal and lachrymal bones

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Agger cells Normal appearence Pneumatised

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Surgical significance When prominent hides view of uncinate

endoscopically Can encroach and fill entire frontal recess

which is medial to it and hence obstruct the frontal sinus

Incomplete removal common cause of surgical failure

If pneumatised removal can cause injury to lacrimal apparatus.

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Lamina papyracea Lateral wall of ethmoid labyrinth Smooth, papery thin bone with dehiscences Cone shaped, wide ant and narrow post Provides attachment to ground lamella of MT Endoscopically identified as a medial bulge on

pressing the orbital contents which return to normal with release of pressure

Radiologically delineated best on coronal and axial cuts

Yellow coloured

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Surgical importance Faster spread of infection into orbit from

ethmoids Voilation of lamina alone with intact periorbita

rarely causes serious complications Can get damaged during

Uncinectomy Widening of ostium Removal of bulla Dissection of post ethmoid complex

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Ground lamella Forms the distinction between the ant and post gp of

sinuses It is constant, complete, best developed and strongest of

the lamellas formed by mid 1/3 of MT Ant 1/3 of MT is entirely vertical, inserts directly into skull

base Mid 1/3,line of insertion changes sharply inferiorly (free

vertical segment seen in frontal plane) Post 1/3 of MT ground lamella turns sharply towards

horizontal forming roof of post 1/3 of MT The pattern of insertion contributes to stability

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After removing ant ethmoids

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Anatomic variations Free vertical segment can be oriented

postsup. by well pneumatised ant ethmoidal air cells (esp with developed lateral sinus)

Cells of post ethmoids can bulge it anteriorly.

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Ant lat and post med view

Indentation by lateral sinus and post ethmoid cells

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Roof of ethmoid Also termed fovea ethmoidalis Domes of top most ethmoid cells bulge into

it Ant part higher than post, sloping from ant

to post at 15 degrees Med wall in sup part formed by frontal bone

and inf part by lamina cribrosa Ant ethmoidal artery pierces the lat lamella

of lamina cribrosa

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Surgical importance Ant ethmoidal artery

intimately related Identification

endoscopically: follow ant surface of

Ethmoid bulla in direction of roof

If bulla extends to roof,seen adjacent to this point 1-2 mm posteriorly

If not may be seenin lateral sinus

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Posterior ethmoid cells Ground lamella forms

the partition between ant and post ethmoid air cells

Located post and sup to ground lamella

No of cells vary b/w 1 and more than 5

Drain into the sup or supreme meati

Of great importance to sinus surgeons as they can develop lat and sup to sphenoid sinus

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Surgical importance Most vulnerable point-jn of rostrum with roof of

post ethmoid (can be mistaken for sphenoid –entry into cranium)

Dissection in the posterior Ethmoids could result in trauma to the optic nerve which is adjacent

Precaution while entering sphenoid inferomedial approach in posterior ethmoid safest way for sphenoid is to extend from

sphenoethmoid recess Lamina papyracea forming lateral wall may show

dehiscence , orbital content may prolapse

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Onodi’s cell ONODI cells( Sphenoethmoidal cell) the most

posterior ethmoid cell, could extend posteriorly along the lamina Papyracea into the anterior wall of the sphenoid sinus.

Incidence-9-12% In presence of Onodi’s cell optic nerve and med

rectus ms lie in close relation with lat wall of these cells- vulnerable to injury during surgery

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Onodi’s cell Endoscopic view

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Frontal sinus Pyramidal shaped air

cells expanded between anterior and posterior tables of the vertical plate of frontal bone.

Theories: direct extension of the

frontal recess by end of 2nd yr one

ant Ethmoid cell migrate upward and forms frontal sinus

Ethmoid infundibular cell

Endoscopic view

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Frontal recess Through which the

final clearance from frontal sinus takes place Medially is middle

turbinate Posteriorly is bulla Laterally is lamina

Papyracea Anteriorly frontal

process of maxilla

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Endoscopic appearence

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Radiological appearence

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Applied aspect Considering complexities of frontal recess serial

CT scans required to know the exact anatomy Infections from frontal sinus can spread

through its thin posterior wall resulting into extradural abscess.

Extensively pneumatised agger nasi can be mistaken for the frontal recess or sinus. If opened and mistaken for a frontal sinus, the residual posteriosuperior wall of the agger nasi cell can scar and iatrogenic stenosis of the frontonasal connection can occur

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Sphenoid sinus Pneumatize from

sphenoethmoidal recess from birth

Extensive variation 3 types based on

pneumatisation Conchal(fetal) 2% Presellar(juvenile)

10-24% Sellar(adult) 86%

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Relations

Superior : thin bone, base of skull Direct contact with olfactory nerve, optic

nerve & optic chiasma & Hypophysis Continues with roof of Ethmoid so landmark

for dissection Lateral wall: normally thin layer of bone cover

optic nerve Internal carotid artery

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Endoscopic appearence Post ethmoid cells

removed Interior of sphenoid

sinus

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Anatomic variations Variations in course of ICA in relation

to sphenoid sinus Result in different pattern of bulge in

wall of the sinus

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Applied aspect Optic nerve extend backwards and disappears

towards post wall. ICA adjacent during passage through cavernous

sinus May not have a resistant bony covering

25% ICA partially dehiscent 6% dehiscent optic nerve

Maxillary nerve(V2) may also be seen on lateral wall as a bulge, may even be surrounded by pneumatisation

Canal for vidian nerve may bulge on floor of sphenoid sinus

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Endoscopic appearance after widening of ostia

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Widening the horizon Virtual 3-D imaging of sinuses Combined radiological, endoscopic and 3-D

assessment pre operatively Individual flexible sinoscopes 3-D CT Aided Surgery

3-D CT Reconstruction Skull Markers Sensors on Endoscope and Instruments Realtime Visualisation of Location of Instruments

within Sinuses during any procedure

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Conclusions Endoscopic anatomy crucial for any

surgery Variations in anatomy is the rule Correlation with imaging to interpret

anatomy correctly Ever learning experience

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References Functional endoscopic sinus surgery-

Stammberger Scott Brown’s otolaryngology, head and

neck surgery, 7th Edition Anatomical principles of endoscopic sinus

surgery-Renuka Bradoo Comprehensive review of functional

endoscopic sinus surgery-AP Singh Endoscopic sinus surgery,a practical

approach-SK Kaluskar Various internet search results.

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Thank You for a patient hearing