The LaryngoscopeVC 2010 The American Laryngological,Rhinological and Otological Society, Inc.

Effect of Head Position and SurgicalDissection on Sinus Irrigant Penetrationin Cadavers

Deepti Singhal, MD; Erik Kent Weitzel, MD; Elissa Lin; Brent Feldt, MD; Brian Kriete, MD;

Kevin Christopher McMains, MD; May Thwin, MBBS; Peter-John Wormald, MD

Background: Effective treatment for recalci-trant rhinosinusitis requires unobstructed surgicalmarsupialization of sinus cavities and use of deliverysystems that will topically penetrate the sinuses.

Aims: To determine the extent of sinus penetra-tion achieved with nasal irrigation by varying theostial size and head position.

Methods: Ten thawed fresh-frozen cadaverheads were dissected in a staged manner. After eachstage of dissection, sinus squeeze-bottle irrigationswere performed in three head positions, and endo-scopes placed via external ports into the sinus cav-ities viewed the sinus ostia. An ordinal scale wasdeveloped to grade ostial penetration of irrigations.Three reviewers independently graded the outcomes.

Results: Irrigant entry into sinuses increasedwith ostial size (P < .001) and the greatest differen-tial of improvement in sinus penetration is obtainedat an ostial size of 4.7 mm. Stages 2 and 3 (largersinus ostia) of maxillary and sphenoid dissectionshave statistically greater irrigant penetration relativeto earlier stages. Frontal sinus irrigation is worse invertex to ceiling head position. There does not appearto be any significant advantage to head position withmaxillary and sphenoid sinuses.

Conclusions: This study shows that the largerthe sinus ostium, the better the penetration of irri-

gant into the sinus, with an ostium of at least 4.7mm allowing maximal penetration in the maxillaryand sphenoid sinuses. The same benefit was notnoted in the frontal sinus. Head position was only rel-evant to the frontal sinus where less penetration wasseen with the head neutral (vertex to ceiling) positionwhen compared to forward angled positions.

Key Words: Nasal irrigation, douching, sinus,sinusitis, frontal, maxillary, sphenoid, cadaver, ostialsize, head position.

Level of Evidence: 1c : all or none prospectiveseries

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INTRODUCTION:One of the important drivers of recalcitrant infec-

tions after surgical management of chronic rhinosinusitis(CRS) is thought to be bacterial biofilms.1–3 Bacterial bio-films are resistant to systemic antibiotics; thus,consensus opinion in the literature is that the optimalroute of treatment to achieve reduction in biofilm popula-tions is through topicalization.3 However, topicaltreatment in active CRS is hampered by inconsistentdelivery of medications to the target tissue. Grobleret al.4 showed that sinus irrigant does not reliably pene-trate unoperated sinuses or cases with ostial obstruction.St. Martin et al.5 states that topical therapy for chronicsinusitis may be more feasible in the postoperative popu-lation. Thus, our recent discovery of a critically sizeddiameter to guarantee ostial penetration gave sinus sur-geons a target ostial size to aid topical delivery.4

Factors that improve irrigant penetration of sinusostia include delivery system, particle size, ostial size,irrigant surface tension, and force vector of irrigant rela-tive to ostial position. Nasal delivery experimentationwith drops, lavages, sprays, and nebulizers has shownvariable degrees of sinus penetration.5–8 One such studyconducted by our department9 studied sinus irrigationwith a nasal spray, nebulizer, and douching bottle, andfound that douching was the most effective in penetrat-ing the maxillary sinus and frontal recess afterFunctional Endoscopic Sinus Surgery (FESS). Saijo

From the Department of Surgery—Otorhinolaryngology Head andNeck Surgery (D.S., M.T., P.-J.W.), The Queen Elizabeth Hospital, and theUniversity of Adelaide, Adelaide, South Australia; Rhinology Section,Otolaryngology Head and Neck Surgery (E.K.W., E.L., B.F., B.K.), Wilford HallMedical Center, Lackland Air Force Base, Texas, U.S.A.; University ofTexas Health Science Center at San Antonio (K.C.M.), San Antonio, Texas,U.S.A.

Editor’s Note: This Manuscript was accepted for publication May5, 2010.

This study was not supported by any external funding.Conflict of interest: P.J. Wormald is a consultant for Neilmed and

receives royalties for design of instruments from Medtronic ENT. Noother conflicts of interest identified.

Send correspondence to Dr. Peter-John Wormald, Department ofOtorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hos-pital, 28 Woodville Road, Woodville South, South Australia 5011, Aus-tralia. E-mail: pjwormald@professorwormald.com.au

DOI: 10.1002/lary.21092

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et al.10 performed a cast model study of nebulized parti-cle deposition and showed that higher flow rates,smaller particle size, and larger os allow for better pene-tration into the maxillary sinus.

From this background, unobstructed open sinusostia and the use of a reliable delivery system arerequired for effective treatment for postoperative recalci-trant CRS. To date, no study has evaluated thepenetration of sinuses by varying ostial sizes and headpositions. Our study addresses these issues, and addi-tionally, describes a novel visualization technique byplacing endoscopes into the sinus through external portswithout obstructing the sinus ostium providing accuratequantification of sinus irrigant penetration.

METHODSInstitutional review board (IRB) exemption was obtained

from both Queen Elizabeth Hospital and Wilford Hall MedicalCenter before initiation of the study.

Cadaver Preparation and VisualizationBefore starting dissection on the 10 thawed fresh-frozen

cadaver heads, 4-mm drillholes were placed in both maxillary,frontal, and sphenoid sinuses of each specimen for an intrasinuspositioning of the nasal endoscope. Maxillary sinus access wascreated through the canine fossa utilizing standardized maxil-lary trephination technique.7 Frontal sinus access was obtainedby transilluminating the frontal sinus and creating a drillholemedially in the ipsilateral frontal sinus from a superior routethrough the anterior cranial fossa. Sphenoid sinus access wasobtained by identifying the sella in the middle cranial fossa andcreating two drillholes just anterior to this landmark on eitherside of midline.

Either a 0- or 30-degree nasal endoscope was utilized asnecessary to obtain an excellent view of the sinus ostia duringirrigation. Ostial dimensions were measured based on its sizerelative to the known size of an instrument. The smallest diam-eter of a nonround ostium was utilized for analysis.

Technique of Sinus IrrigationNeilMed sinus rinse plastic squeeze bottles (240 mL) were

used for this study. The irrigating solution was dyed using ablue food coloring agent/vegetable dye purchased from local gro-cery store. It was added in a quantity adequate enough to tintthe solution dark blue to be visualized endoscopically, but notconcentrated enough to stain the sinus mucosa. The bottleswere filled to the premarked line on the bottle. For head posi-tions where the tilted position would cause the dependentportion of the bottle to be higher than the irrigating nipple, thestraw was removed.

Cadaver heads were tested in three different positions: 1)eyes and face pointed directly at the floor (0 degree, vertex towall), 2) eyes and face pointed directly at the wall (90 degrees,vertex to ceiling), and 3) an angled position directly betweenthe above two positions (45 degrees). Nasal douching wasstandardized by utilizing only two strong male surgeons for allirrigations; both were both given the instruction to give onestrong squeeze at a rate that feels aggressive but tolerable.The bottle was aligned on an axis parallel to the nasal dorsumand aimed toward the ipsilateral medial canthus. The dyeentering the sinuses through the natural/surgical ostia wasviewed endoscopically through endoscopes placed through the4-mm drill holes. Three reviewers actively watched eachattempt at irrigation and graded the resulting amount of bluesolution that was seen to enter each sinus through the respec-tive ostia. Data was based on a scale of irrigant penetratingthe sinus (Table I) and was averaged from the three reviewersfor each sinus.

Stages of Cadaveric Dissection and IrrigationUndissected heads were recorded as surgery level 0 and

were considered as controls. Bilateral sinuses of all 10 undis-sected cadaveric heads were irrigated as per the techniquedescribed above and irrigation outcomes were recorded formaxillary, frontal, and sphenoid sinuses. The cadaveric speci-mens were then dissected in a staged manner and aftercompletion of each stage the nasal cavity was again irrigatedand outcomes recorded. The stages (Table II) were designed tocorrelate to typical sinus ostial outcomes from conservative toradical. Stage 1 dissection included maxillary uncinectomywithout widening of the ostium, superior turbinectomy with ex-posure but no enlargement of the sphenoid ostium, and Draf Isinusotomy (anterior ethmoidectomy with exposure of the fron-tal ostium). Stage II dissection included maxillary andsphenoid ostium enlargement to approximately 5 mm in size, acomplete ethmoidectomy, and a Draf IIa frontal sinusotomy (re-moval of all cells obstructing the frontal ostium andenlargement of the ostium to its maximal diameter without re-moval of the frontal sinus floor medial to the middleturbinate). Stage III dissection included widest possible maxil-lary antrostomy, complete removal of the anterior face of thesphenoid, and Draf III opening of the frontal sinus (a frontaldrillout or modified Lothrop).

TABLE I.Reporting Ordinal Scale for Sinus Ostial Penetration of Irrigating

Solution.

0 No penetration

1 Bubbles/froth

2 Drops/dribble

3 Filled up to one-third of sinus

4 Filled up to two-thirds of sinus

5 Completely full, spills out of sinus

TABLE II.

Stages of Dissection for the Sinuses.

Sinus

Stage of Dissection

0 1 2 3

Maxillary Undissected Uncinectomy 5 mm Ostium Widest possible

Frontal Undissected Draf I Draf IIA Draf III

Sphenoid Undissected Superior turbinectomy 5 mm Ostium Remove sphenoid face

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Statistical MethodsAnalysis was performed using both SPSS 16.0 and Micro-

soft Excel 12.2.0. Irrigation penetration was treated as ordinaldata and minimum ostial size was treated as continuous data.A Friedman test was utilized for repeated measure ordinaldata, and Wilcoxon Signed-Ranks Test was used to evaluate allpaired ordinal data. All other statistical methodology is pre-sented after the described analysis.

RESULTSThe race and sex demographics of cadavers used in

this study are unknown due to IRB constraints. Onecadaver had congenital absence of the frontal sinuses,one cadaver had a unilateral frontal sinus, and in onecadaver we were unable to identify one of the sphenoidsinuses with the described technique.

Reporting ScaleA reporting scale (Table I) was developed to estab-

lish the degree of sinus penetration by the irrigant.

Irrigant Penetration by Sinus. The maxillarysinus shows significantly worse penetration than thestatistically similar frontal and sphenoid sinusesthrough the first two levels of dissection. When allsinuses are maximally dissected during the third stageof surgery, the statistical differences disappear (Fig. 1).Friedman test for the maxillary sinus showed a signifi-cant increase in penetration with increasing stage ofdissection (P < .001). Post hoc testing noted significantincreases in penetration between stages 1, 2, and 3 (P <.001). The sphenoid sinus also showed statistically sig-nificant improvement in irrigation with increasing stageof dissection (P < .001 by Friedman). Post hoc testingnoted statistical improvement between sphenoid stages 2and 3 relative to control and stage 2 improvement rela-tive to stage 1 (all P < 002 by Wilcoxon). The frontalsinus displays a general trend of improvement througheach stage of dissection, but Friedman test for repeatedmeasures does not show any statistically significantdifferences.

Head PositionPaired analysis was used to examine one head posi-

tion against another for similar surgical dissections. Theonly sinus that showed an advantage with a specifichead position was the frontal sinus (Fig. 2) showing sta-tistical improvement when moving from the 90� to 45�

position (P ¼ .011 by Wilcoxon Signed-Ranks Test) whenall data was analyzed together.

Ostial SizeWhen the data on sinus penetration for all sinuses

is pooled, a graph representing the mean differences inpenetration between ostial size ‘‘break’’ points was cre-ated. A second-order curve fit to the differentials showsthat ostial size of 4.7 mm gave the best sinus penetra-tion of irrigant into the sinus (Fig. 3).

DISCUSSIONThis is the first study analyzing the effect of sinus

irrigation on the maxillary, frontal, and sphenoid sinusesusing direct intrasinus endoscopic visualization withvarying ostial sizes and head positions. Our results showthat gross penetration of the irrigant through sinus ostiais generally improved by surgical ostial size (Fig. 1). We

Fig. 1. Heavy penetration (�level 3 irrigant penetration) of sinusirrigant tends to improve with increasing stage of sinus surgery.

Fig. 2. Frontal sinus heavy penetration (�level 3 irrigant penetra-tion) is worse when nose is toward the wall compared to the 45position, whereas the 0 and 45 positions are not statistically differ-ent. Draf III does not appear to follow this trend.

Fig. 3. Ostial size that has the greatest potential for increasingpenetration of nasal douche into a sinus. Based on the ability toachieve level 3 or greater penetration, second-order curve fittingto data defines maximum benefit obtained at 4.7 mm.

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found that the maxillary sinus has worse penetrationthan the other sinuses at lower stages of dissection.Because there is little improvement in irrigant penetra-tion between a stage 0 and 1 maxillary surgery, theshielding effect of the uncinate is most likely not playinga major role in this phenomenon and the poor penetra-tion is best explained by an unfavorable force vector ofnasal irrigant running perpendicular to the entrance tothe maxillary sinus. In a cast model study10 a similareffect was seen when a 45� nozzle insertion angle signifi-cantly increased the aerosol particle deposition in themaxillary sinus and Osteomeatal Complex (OMC) com-pared to a 30� nozzle. This study definitively shows thatincreasing the diameter of the maxillary ostium resultsin increasing penetration; however, our results are not asstraightforward to interpret in the case of the sphenoidand frontal sinuses. Irrigation potential of the sphenoidsinus improves through the first three stages of surgery,but then is maximized after a 5-mm os is obtained (stageII dissection). The frontal sinus shows overall stable pen-etration throughout all stages of dissection.

While developing an intrasinus irrigant penetrationscale, we noted that level 1 and 2 penetrations, althoughdistinct from one another, were noted to yield minimal ifany noticeable irrigant contact with sinus mucosa. How-ever, level 3 and above penetration resulted in grosscoverage of sinus mucosa. The threshold that we used todenote heavy penetration (�3) for many of the statisticalanalyses was deliberately chosen to represent that levelof sinus penetration felt to have a meaningful topicaleffect on sinus mucosa. As previously discussed, recalci-trant CRS may result from mucosal biofilms1–3 andtopical routes of drug delivery to this sinus mucosa playan important role in treatment.5

Significant controversy surrounds optimal headposition during sinus irrigation. Numerous papers docu-ment the advantage of one head position overothers.4,11,12 We found that the only sinus impacted byhead position was the frontal sinus (Fig. 2). Specifically,when studying undissected cadavers, Draf I, and DrafIIA dissections as a group (stages 0–2), there appears tobe an advantage of the 45� position relative to the 90�

position (nose to the wall). Therefore, this study givesobjective evidence that leaning over a sink and irrigat-ing with the nose pointed toward the sink confersincreased benefit for irrigating the frontal sinus. Thisposition also is practical for the patient for hygienic dis-posal of waste irrigation and agrees with manufacturerrecommendations.

Finally, this study confirms an advantage of anostial size of approximately 5 mm. Previously we foundthose ostia larger than 3.95 mm were reliably pene-trated by irrigation.4 Although this study did not find anabsolute cutoff above which 100% of ostia were pene-trated, we did show that ostia less than 4.7 mm indiameter represent the maximal difference in irrigantpenetration potential relative to those ostia greater than4.7 mm in size (Fig. 3). This critical ostial size may playa significant role in cases where postoperative topicalmedical management in the form of antifungal, antibiot-ics, and steroids is required.

An interesting observation was that penetration ofirrigant into the frontal drillout (Draf III) cavity wasunpredictable as we expected to see similar outcomes asin the maxillary sinus. Our hypothesis for this phenom-enon is that the path of least resistance for irrigationwas through the septal perforation as opposed to enter-ing the frontal neo-ostium, often leading to minimalentry of irrigant into the sinus. The methodology in thisstudy dictated that data was reported after only a singlesinus irrigation. If multiple irrigations were performedbetter penetration may have been achieved. Future stud-ies should address the ideal number of irrigationsrequired to maximize irrigation potential.

CONCLUSIONIrrigant penetration of a sinus requires adequate

sinus ostial size to allow topical delivery of medication.This study shows the benefits of increasing surgical dis-section in the maxillary and sphenoid sinus forincreasing irrigant penetration. Interestingly, this studydoes not show the same benefit in the frontal sinus.Head position was only relevant to the frontal sinuswhere a disadvantage was seen in the nose to wall posi-tion relative to the angled forward position.

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bacterial and fungal biofilms in chronic rhinosinusitis.Am J Rhinol Allergy 2009;23:556–561.

2. Psaltis AJ, Weitzel EK, Ha KR, et al. The effect of bacterialbiofilms on post-sinus surgical outcomes. Am J Rhinol2008;22:1–6.

3. Suh JD, Cohen NA, Palmer JN. Biofilms in chronic rhinosi-nusitis. Curr Opin Otolaryngol Head Neck Surg 2010;18:27–31.

4. Grobler A, Weitzel EK, Buele A, et al. Pre- and postopera-tive sinus penetration of nasal irrigation. Laryngoscope2008;118:2078–2081.

5. St. Martin MB, Hitzman CJ, Wiedmann TS, et al. Deposi-tion of aerosolized particles in the maxillary sinusesbefore and after endoscopic sinus surgery. Am J Rhinol2007;21:196–197.

6. Hyo N, Takano H, Hyo Y. Particle deposition efficiency oftherapeutic aerosols in the human maxillary sinus. Rhi-nology 1989;27:17–26.

7. Singhal D, Douglas R, Robinson S, et al. The incidence ofcomplications using new landmarks and a modified tech-nique of canine fossa puncture. Am J Rhinol 2007;21:316–319.

8. Valentine RJ, Athanasiadis T, Thwin M, et al. A prospectivecontrolled trial of pulsed nasal nebulizer in maximallydissected cadavers. Am J Rhinol 2008;22:390–394.

9. Wormald PJ, Cain T, Oates L, et al. A comparative study ofthree methods of nasal irrigation. Laryngoscope 2004;114:2224–2227.

10. Saijo R Majima Y, Hyo N, Takano H. Particle deposition oftherapeutic aerosols in the nose and paranasal sinusesafter transnasal sinus surgery: a cast model study. Am JRhinol 2004;18:1–7.

11. Karagama YG, Lancaster JL, Karkenevatos A. Delivery ofnasal drops to the middle meatus: which is the best headposition? Rhinology 2001;26:226–229.

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