Anatomic And Clinical Research Of The Aponeurosis-müller’s Muscle Complex

Objective：Blepharoptosis is a common condition characterized by an abnormallylow-lying upper eyelid margin that is less than2.0mm above the midpoint of thepupil or greater than2.0mm lower than the contralateral eyelid margin.Numerous method have been reported in the literatures to correct blepharoptosisin the past years. Although different method has its own indications andadvantages. It also carries a risk of complications that need to be carefullyconsidered when choosing a technique for surgical treatment. To reduce the riskof these complications, we have used a modified levator aponeurosis-müllermuscle complex reinsertion technique to correct blepharoptosis. The purpose ofthis study was to evaluate the outcomes of ptosis correction surgery using thistechnique after a anatomic and clinical research of the aponeurosis–müller’smuscle complex.Methods：In the first section, five adult cadaveric head preserved with10%formalinwere dissected at the upper eyelid region with a open removal of the superiororbital wall. The mark and location of important structures were furtherdetermined. The aponeurosis–müller’s muscle complex, the leavtor aponeurosis, the Müller’s muscle and Whitnall ligament were exposed, illustrated and therelevant distance was measured.In the second section,75eyelids of49patients with congenitalblepharoptosis were treated with the modified levator aponeurosis-müller’smuscle complex reinsertion technique between2007and2011. The follow-upperiod ranged from6months to4years, with a mean follow-up of23months.Preoperative ptosis severity was compared with the degree of ptosis correctionby using the Cochran-Mantel-Haenszel statistic. Preoperative levator functionwas compared with the degree of ptosis correction and the postoperative levatorfunction by using Fisher exact test for paired data.In the third section, a total of13patients were diagnosed with BPES andunderwent single-stage correction by either the modified levatoraponeurosis-müller’s muscle complex reinsertion technique or frontalis muscletransfer technique, combined with Mustardé medial canthoplasty and Fox lateralcanthoplasty from2007to2013. The follow-up period ranged from1to6years,Statistical analysis was performed by paired t-test and independent t-test, toevaluate the pre-and postoperative HLFL, VLFW, IICD, and IICD/HLFL data.A p-value of <0.05was considered to be statistically significant.Result:In the first section, the total length of the levator aponeurosis-müller’smuscle complex is52.09±1.43mm; Separated by Whitnall ligament, the lengthof the muscle is36.09±0.72mm；The length of the aponeurosis is16.04±1.50mm; The length of müller’s muscle is10.41±0.73mm.In the second section, Sufficient correction was obtained in59(78.7%) of75eyelids, and insufficient correction was obtained in16eyelids (21.3%).Eyelids with preoperative levator function of greater than4mm had a higherrate of sufficient correction than those with preoperative levator function lessthan4mm (91.5%vs57.1%; P G0.05). The number of eyelids with levatorfunction greater than4mm increased from47preoperatively to62postoperatively (P<0.05).In the third section, Significant differences were observed between themean pre and postoperative values for VLFW, HLFL, IICD and the IICD/HLFLratio (all p <0.0001). The value of IICD decreased with surgery and HLFLincreased with surgery, which led to an overall decrease in the IICD/HLFL ratiopostoperatively compared to the preoperative value. In the frontalis muscletransfer group, the IICD/HLFL ratio was less than1.3for62.5%of patients andgreater than1.5for25%of patients. In the levator aponeurosis-müller’s musclecomplex group, the IICD/HLFL ratio was less than1.3for80%. There was nosignificant differences observed between the two groups.Conclusion：1. The levator aponeurosis-müller’s muscle complex originated from themusclar tendinous ring of the orbital apex. The total length of the levatoraponeurosis-müller’s muscle complex is52.09±1.43mm; Separated by Whitnallligament is located16.04±1.50mm away from the supratarsal border. 2. Müller’s muscle originated from the deep part of levator aponeurosismuscle. The length of müller’s muscle is10.41±0.73mm. The interspacebetween the levator aponeurosis-müller’s muscle complex and conjunctiva isquite easy to be dissected dring operation.3. The modified levator aponeurosis-müller’s muscle complex reinsertiontechnique is effective for any congenital ptosis with levator function and it canimprove levator function after the operation.4. Either levator aponeurosis-müller’s muscle complex reinsertiontechnique or frontalis muscle transfer technique are effective for single-stagecorrection of blepharophimosis-ptosis-epicanthus inversus syndrome combinedwith Mustardé medial canthoplasty and Fox lateral canthoplasty.