Minimally Invasive Strabismus Surgery For Horizontal .

Adel Osman et al.with limbal approach Esotropia or Exotropia,Recession or Resection.Surgical technique for traditional,limbal approach: Limbal periotomy with tworadial relaxing incisions are performed over themuscle .With blunt Wescott scissors the episcleral tissue is separated from the musclesheath and sclera. When the borders of themuscle have been identified, the muscle ishooked. Then a meticulous dissection of thecheck ligaments and intramuscular membraneis performed.Continue for recession: Vicryl sutures(6-0) are placed at the upper and lower poles ofthe muscle insertion, locked and secured. Themuscle is cut at the insertion and the muscle iscarefully resutured at sclera at the plannedposition after measurging the distance withcaliber.Continue for resection or plication:Vicryl sutures (6-0) are passed at the upper andlower pole of the muscle at the planned positionfor resection or plication, locked and secured.The muscle is divided in front of the suturelevel for resection or folded over for plication.The surgical procedure is finished byreadapting the conjunctiva, applying four to sixsutures with Vicryl 8-0. At the end of surgery,combination of antibiotic and steroid ointmentwas applied. No eye patch was used.Group (2): included 25 patients treatedwith MISS either Esotropia or Exotropia,Recession or Rescection.Surgical technique for MISS: A limbaltraction suture (e.g., 6-0 silk) is passed. Two radialkeyhole para insertional cuts are made parallel tothe upper and lower margin of the muscle. Thelength should be 1 mm shorter than the plannedmagnitude if the rectus muscle recession orplication less than 5 mm and 2 mm if recession orplication more than 5 mm. Small sub-Tenontunnels joining the two incisions are made withWestcott scissors over the surface of the muscle,avoiding the muscular vessels. The muscle ishooked and cauterization of the prominent bloodvessels at the insertion underneath the conjunctivais performed.Continue for recession: Vicryl sutures(6-0) are placed at the upper and lower poles ofthe muscle insertion, locked and secured. Themuscle is cut at the insertion under theconjunctiva. The muscle is carefully re sutured atsclera at the planned position.Continue for resection or plication:Vicryl sutures (6-0) are passed at the upper andlower pole of the muscle at the planned positionfor resection or plication, locked and secured.The sutures are placed through the muscleinsertion ensuring an adequate anchoringscleral bite. The muscle is divided in front ofthe suture level for resection or folded over forplication. The surgical procedure is finished byreadapting the conjunctiva, applying singlesuture with Vicryl 8-0. At the end of surgery,combination of antibiotic and steroid ointmentwas applied. No eye patch was used.Follow up: The patients were examinedat one week, three week and six week and postoperative correction at first week, third and sixmonths.Statistical AnalysisData were collected, revised, coded andentered to the Statistical Package for SocialScience (IBM SPSS) version 20. Qualitativedata were presented as number and percentageswhile quantitative data were presented as mean,standard deviations and ranges.Chi-square test or Fisher exact testwas used to compare between qualitative data.The comparison between two groups regardingquantitative data with parametric distributionwere done by using Independent t-test whilemore than two group regarding quantitativedata with parametric distribution were done byusing One Way Analysis of Variance(ANOVA).The confidence interval was set to 95%and the margin of error accepted was set to 5%.So, the p-value was considered significant asthe following:P 0.05: Non significantP 0.05: SignificantP 0.01: Highly significant.RESULTSTable (1): Comparison between MISS group and control groups as regard Visibility of surgical wound.7777

Minimally Invasive Strabismus Surgery for Horizontal Concomitant StrabismusMISS 0%00.0%1872.0%728.0%00.0%00.0%Visibility ofsurgical woundNegative st1 week Negative rd3 week Negative Six week : Independent t-test;Control 0%14.0%1248.0%1352.0%00.0%00.0%Test 3NS*: Chi-square test; NS: Non significant; S: SignificantRegarding Visibility of surgical wound no significant difference at first and six week butsignificant difference at third week.Table (2): Comparison between MISS group and control groups as regard post-operative conjunctivalredness.Post operativeconjunctival rednessNegative 1st week Negative 3rd week Negative Six week MISS 0%00.0%25100.0%00.0%00.0%00.0%Control 0%00.0%2392.0%14.0%14.0%00.0%Test 3NS : Independent t-test; *: Chi-square testNS: Non significantRegarding post-operative conjunctival Redness no significant difference at first, third and sixweek.Table (3): Comparison between MISS group and control groups as regard Patient discomfort.Patient discomfort1stweek3rd weekSix weekNegative Negative Negative MISS %00.0%2184.0%416.0%00.0%00.0%Control 0%00.0%2288.0%312.0%00.0%00.0%Test 4NS : Independent t-test; *: Chi-square testNS: Non significantRegarding Patient discomfort there was no significant difference at first, third and six week.Table (4): Comparison between MISS group and control groups as regards early postoperative surgicalcomplications.MISS groupControl group7777Test value*P-valueSig.

Adel Osman et al.Surgical openingrelated complicationsNoLid swellingAllergic reactionStitch granulomaCome ulcerTenon prolapseDellen for 0.312NSNSNSNSNSNSNS : Independent t-test; *: Chi-square testNS: Non significantAs regard surgical complications were reported in 20 % of cases MISS and 26 % of cases limbalapprpach, it was in the form of lid swelling in 5 cases (2 in MISS and 3 in limbal approach), allergicreaction in 1 cases of MISS, Stitch granuloma 2 cases one in each group, corneal ulcer one case ofMISS, tenon prolapse one case of limbal approach, Dellen formation in one case of limbal approach.With there was no significant difference between MISS group and control groups.Table (5): Muscle alignment among the studied patients with various pattern of horizontal deviation atone week and one month.Correction post-operativeOrthoOrtho with glassesResidual ETResidual ET with glassesResidual XTRecurrent XTConsecutive ETMISS rol groupNo.%2288.0%14.0%14.0%00.0%14.0%00.0%00.0%Test S : Independent t-test; *: Chi-square testNS: Non significantSuccess rates:Success was considered to be achieved a postoperative alignmenet within 10 PD, and failurewas considered as postoperative angles greater that 10 PD.In MISS group, the success rate was 20 cases at 1 week of follow up. In limbal approach group,success rate was 22 cases at 1 week of follow up. The difference between both groups was statisticallyinsignificant.Table (6): Muscle alignment among the studied patients with various pattern of horizontal deviation atthree months.Follow up at 3 monthsOrthoOrtho with glassesResidual ETResidual ET with glassesResidual XTRecurrent XTConsecutive ETMISS rol groupNo.%2184.0%14.0%14.0%00.0%14.0%00.0%14.0%Test S : Independent t-test; *: Chi-square testNS: Non significantThe success and failure rates were again compared at 3 months follow up and the results wereas follow; in the MISS group, 19 patients were successfully aligned. In the limbal approach group, thesuccess rate was 21 cases, the difference between both groups was statistically insignificant.Table (7): Muslce alignmnet among the studied patients with various pattern of horizontal deviation atsix months.Follow up at 6 monthsMISS groupControl group7777Test value*P-valueSig.

Minimally Invasive Strabismus Surgery for Horizontal Concomitant StrabismusOrthoOrtho with glassesResidual ETResidual ET with glassesResidual XTRecurrent XTConsecutive ETNo.17210221%68.0%8.0%4.0%0.0%8.0%8.0%4.0% : Independent t-test; *: Chi-square testNS: Non significantThe Success and failure rates wereagain compared at 6 months follow up and theresults were as follow; in MISS group, 17patients were successfully aligned. In the limbalapproach group 20 patients were successfullyaligned, there was no statistically significantdifference between the two 0000.5510.5511.000NSNSNSNSNSNSNSsingle vision, visual acuity, refractive change,or complications .According to conjunctival incision inMISS four cases needed extended incision andwe convert them to limbal incision, alsohaemorrage was recorded in one case and weconverted it to limbal incision, these cases notincluded in this study these results are inagreement with Merino et al. (16) who statedthat in cases with hard to control bleeding thismay necessitate keyhole enlargement that willallow adequate exposure for cauterization.Disruption of the anterior ciliaryarteries did not occur in any of our cases,although this complication was encountered byWright and Lanier in their study on animalmodels while dissecting the check ligaments ofthe inferior rectus muscle (17).The results regarding visibility of surgicalwound at first week showed that there was nostatistical significant difference between MISS andlimbal approach but number of cases as regardvisibility of surgical wound is higher in limbalapproach than MISS. At third week there wasstatistical significant difference between MISS andlimbal approach. At six months there was nostatistical significant difference between twogroups but number of cases was less in MISS thanlimbal approach, this conicide with Pellanda andMojon (13) who stated that the real value of MISSlies in the long-term benefit of reduced fibrosisthat will facilitate future reoperations.This also agrees with Mojon whostated that the advantages of MISS includeddecrease post-operative visibility of surgicalwound (11).The result as regard post-operativeconjunctival redness at first week, third weekand six months showed that no statisticalsignificant difference between MISS and limbalapproach but number of cases as regardconjuntival redness is less in MISS than limbalapproach all time. This study agrees with thestudy done by Mojon in the first six months ofthe follow up period who stated that theDISCUSSIONThe aim of this study was to evaluateand compare between minimally invasivestrabismus surgery and the standard limbalapproach for horizontal concomitant strabismusas regards to visibility of surgical wound, surgicalopeningrelatedcomplications at one week, three week and sixweek and post-operative correction at firstweek, third and six months.In this study, a postoperative deviationwithin 10 PD was considered a successfulresult.It was found the success rate in thisstudy was 21 (84%) cases in MISS at 1 weekpostoperatively while the success rate in limbalapproach at the same time was 23 (90%) cases.Three months postoperatively, the success ratein MISS was 21 (84%) cases but the successrate in the limbal approach was 22 (88%) cases.By six months postoperatively, the success ratein MISS was 19 (76%) cases and 21 (84%)cases in the limbal approach, the differencebetween the two groups was not statisticallysignificant.This was very similar to another studydone by Ioannis et al. (15), who stated that MISShas equally successful outcomes compared toconventional strabismus surgery (15), alsosimilar to another study done by Mojon (8) whostated that in a 6-month prospective studycomparing patients operated on with MISS (n 20) versus a matched, non-concurrent,retrospective comparison group (n 20),reported that no significant difference wasdetected for final ocular alignment, binocular7777

Adel Osman et al.advantages of MISS include reduced redness ofthe conjunctiva (11).As regard patient discomfort at firstweek, third week and six months there was nostatistical significant difference between MISSand limbal approach but number of cases asregard patient discomfort is less in MISS thanlimbal approach at all times. This study agreewith the study done by Mojon during follow upperiod who stated that this method involvesperforming strabismus surgery through keyholeopenings to decrease tissue trauma, minimizepostoperative complications and patientdiscomfort, and improve surgical outcomes (8).In the present work, at the firstpostoperative week no complications werereported in 80% of cases in MISS and 76 % inlimbal approach. Complications that werereported in the form of lid swelling in 2 cases(8.0 %) in MISS and three cases (12.0 %) inlimbal approach. Allergic reaction one case(4.0%) in MISS. Stitch granuloma occure inone case in each group (4.0%). Corneal ulceroccurs in one case in MISS (4.0%). Dellenformation and tenon prolapse one case in limbalapproach (8.0%), with no significant differencebetween patients group and control group.From this study we noticed that nocomplication specific to each group but somecomplication increase with each technique. Forexample corneal ulcer and scleral perforationincrease with MISS but tenon prolapse, dellenformation and lid swelling increase with limbalapproach.Prolapse of Tenon's capsule occurred inone patient in limal group, but it was so smallthat it needed no treatment and it shrink back toits original site under the conjunctiva. This wassupported by Helveston who stated that theprolapsed Tenon's capsule would shrink backinto the conjunctival wound unless it isexcessive then it should be excised and theconjunctiva overlying it sutured (18).Anterior segment ischaemia was notdetected in any case done either by MISS or limbalapproach. This dose not agree with Kushner BJwho said Preservation of perilimbal episcleralvessels as perilimbal blood vessels remain intactfollowing MISS, the risk of postoperative anteriorsegment ischemia is greatly reduced compared tothe conventional surgical techniques that requiredissection of the limbal conjunctiva (6).As regard post operative scarring ofperi muscular tissue we can not distinguishbetween two groups because no surgicalintervention was done again in both studygroups. Two patients with residual exotropiaaccepted the result; one patient with residualesotropia has no detected angel under glassesand one patient with residual esotropia refusereoperation.The results regarding the amount ofcorrection of the strabismic angles were nearly thesame in both groups denoting that MISS had thesame effects as limbal approach. Number of orthocases in MISS was 21(84%) case post operativelywhich remained as it after three months and thenumber of ortho cases decreased to 19 (76%) caseafter six months in which one case has recurrentexotropia due to amplyopia and another case hasconsecutive esotropia. In comparison with thenumber of ortho cases in limbal approach 23(92%) cases post operatively which decreased to22 (88%) cases after three months and decreaseagain to 21 (84%) cases after six months in whichone case has consecutive esotropia and anothercase has recurrent exotropia due to amplyopiarespectively with no statistical significantdifference between two groups.In the present study according to time ofsurgery MISS time ranged from 20-60 minute withamean of 43.33 10.07 minutes, while limbalapproach time ranged from 15-40 minute withamean of 30.00 5.59 minutes and there was highlystatistically significant decrease of limbal approachtime in comparison to MISS time, and this agreewith Merino et al., who said Surgical time is longer,at least for the surgeon who is unfamiliar withMISS (19).At the end we must reminde that MISStechnique losses some advantages than limbalapproach: Conjuntival recession in esotropiawhich act as augmentation of recession. Largeangel of esotropia or exotropia needs largerincision which is similar to limbal approach.Recurrent strabismus done by limbal approach,fornix incision technique and hang backtechnique is not suitable to be done again byMISS. Some previous surgeries hinder MISStechnique as buckle in retinal detatchment. Notany age suitable for MISS, the recommendedage between 14 and 40 years, small age haveexcssive tenon and old age have inelasticconjunctiva. In recession if sagging occur itmay not be noticed.Fornix incision technique has nearlythe same advantages of MISS as regard patientdiscomfort, visibility of surgical wound andpost operative conjuntival redness so fornixincision considered minimally invasive7777

Minimally Invasive Strabismus Surgery for Horizontal Concomitant Strabismussurgery, this coincide with Merino et al. whostated that this approach results in minimalpostoperative edema or discomfort, and theincision is usually hidden from view and MISSdoesn’t appear to offer much advantage forsurgeons already using a fornix-based approach(16).This also agree with paper done byGranet et al. who stated that we think our fornixsurgery is already minimally invasive, whichavoids disruption of the episcleral perilimbalvessels and we make very small incisions, hookmuscles through these tiny incisions, keepbleeding to a minimum surgical time is longer,at least for the surgeon who is unfamiliar withMISS (20).Muscle disinsertion should be donewith careful attention to the technique, if the cutis placed too close to the sclera, a permanentlyvisible bluish line along the muscle insertionmay ensue. If, on the other hand, the cut isplaced too far from the sclera, the remainingtendon may form a visible elevation of theconjunctiva (16).We want to say that incision is animportant steb in strabismus surgeries andminimal invasive technique has gainedpopularity in many fields of ophthalmology likephacoemusification and other procedures thatenable to early rehabilitation and lesspostoperativediscomfortandequallysuccessful outcomes. So, choice type ofincision and surgery is an important. MISS is agood technique suitable for patient age between10 -40 years, not to larg angel esotropia orexotropia to avoid larg incision, primary not forrecurrent strabismus especially if surgery doneby another technique limbal or fornix and it haslearning curve more than other procedures sowho want to learn MISS must come to watch inthe operating theater and assist one day (11).Although the short-term advantage offaster rehabilitation and more satisfactory cosmesiscan be important for some patients, the real valueof MISS lies in the long-term benefit of reducedfibrosis that will facilitate future reoperationsshould these be needed. The decreased likelihoodof anterior chamber ischemia owing to thepreservation of limbal blood vasculature isobviously an added potential benefit of MISS (13).Fornix-based procedures; this approachresults in minimal postoperative edema ordiscomfort, and the incision is usually hiddenfrom view so considered minimally invasiveprocedure but has disadvantage like MISS it isdifficult to perform in children because of theirprominent Tenon’s capsule, in cases withsignificant preexisting scarring, and in olderpatients with inelastic conjunctiva (16).Limbal approach; this techniquepermitted full visualization of the muscleundergoing operation and avoided excessivescarring and bleeding over the muscle tendon.Some common postoperative unctival redness, corneal dellen, andTenon’s capsule prolapse (10).Undoubtedly MISS is currently thepreferred approach of only a minority of surgeonsworldwide and thus traditional techniquesutilizing limbal or fornix conjunctival incisionsremain most popular in many parts of the world(21).CONCLUSIONFrom the results of this study, it can beconcluded that minimally invasive strabismussurgery technique is an alternative technique tolimbal or fornix technique that can be used onhorizontal muscles especially when Preservationof perilimbal episcleral and early rehabilitation isneeded.REFERENCES1. Darzi A and Mackay S (2002): Recentadvances in minimal access surgery.British Medical Journal, 324(7328):31-4.2. Frueh BR, Musch DC and McDonaldHM (2004): Efficacy and efficiency of asmall-incision,minimaldissectionprocedure versus a traditional approach forcorrectingaponeuroticptosis.Ophthalmology, 111(12):2158-63.3. von Noorden GK (1969): Modification ofthe limbal approach to surgery of the rectusmuscles. Archives of Ophthalmology,82(3):349-50.4. Parks MM (1986): Fornix incision forhorizontal rectus muscle surgery. Americanjournal of ophthalmology, 65(6):907-15.5. Kenneth W, Wright and Puuline H(2006): Anatomy & Physiology of eyemovement, Hand book of PediatricStrabismus & Ambylopia. 3rd Ed; Springerscience Business Media, 24-70.6. Kushner BJ (2007): Comparison of a new,minimally invasive strabismus surgerytechnique with the usual limbal approachfor rectus muscle rece

Objective: the present study aimed to compare the minimally invasive strabismus surgery (MISS) as an alternative to limbal approach for horizontal concomitant strabismus. Patients and Methods: the study included 50 patients of different ages and sexes, presented with transverse