Management of myopathic ptosis

Abstract

Regarding Wong et al's “Management of Myogenic Ptosis,”1Wong V.A Beckingsale P.S Oley C.A Sullivan T.J Management of myogenic ptosis.Ophthalmology. 2002; 109: 1023-1031Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar my concern is 2-fold: (1) the levator advancement technique used in some of their patients, and (2) the involvement of Müller's muscle in the dystrophic process, which was not mentioned.2Jordan D.R Addison D.J Surgical results and pathological findings in the oculopharyngeal dystrophy syndrome.Can J Ophthalmol. 1993; 28: 15-18PubMed Google Scholar The authors' levator advancement surgery involved an anterior approach via the lid crease, through orbicularis and septum, to the levator aponeurosis. “The levator aponeurosis was separated from the tarsal plates and Müller's muscle with Westcott scissors. The medial and lateral horns of the levator muscle were cut, and the band of levator muscle was sutured to the anterior tarsal plate.” Oculopharyngeal muscular dystrophy, one of the myogenic types of ptosis reported by Wong et al, is a very common type of ptosis in this author's area because of the large number of French Canadians. Several years ago I reported my experience with levator aponeurotic advancement surgery in 28 patients (47 eyelids) with this disease over a 2-year period.2Jordan D.R Addison D.J Surgical results and pathological findings in the oculopharyngeal dystrophy syndrome.Can J Ophthalmol. 1993; 28: 15-18PubMed Google Scholar The levator muscle is characteristically infiltrated with fat in this syndrome. The fatty infiltration is quite visible to the naked eye, whereas the aponeurosis appears relatively normal (glistening white). Initially, I dissected the aponeurosis away from Müller’s (horns intact) and tried to advance the aponeurosis onto the tarsal plate, much like the authors have described. As the levator aponeurosis was dissected away from underlying Müller's, the dissection plane would often become very indistinct about 10 mm above the tarsal plate. Müller's muscle was routinely noted to be infiltrated with fat and also appeared very thickened in the overwhelming majority of patients. When I simply advanced aponeurosis over Müller's and onto the tarsus, the lid would come up, but rarely as much as expected or desired. However, if Müller's was also dissected away from conjunctiva and advanced with aponeurosis (horns left intact), the lid would come up higher and more easily. In addition, as Müller's was dissected away from conjunctiva, it was clearly found to be thicker than normal. Histopathological examination of this thickened, fat-infiltrated Müller's confirmed its involvement in the dystrophic process, a finding that was unrecognized in previous literature.3Johnson C.C Kuwabara T Oculopharyngeal muscular dystrophy.Am J Ophthalmol. 1974; 77: 872-877Abstract Full Text PDF PubMed Scopus (40) Google Scholar I have also found Müller's muscle to be very infiltrated with fat and thicker than normal Müller's in myotonic dystrophy and chronic progressive external ophthalmoplegia. I routinely dissect and advance Müller's with levator aponeurosis (horns left intact) in these individuals as well, when ptosis surgery is required. I apply my technique to those myogenic ptosis patients with at least 5 mm of levator function and do not convert to frontalis slings until levator function is less than 5 mm. All surgeries are done under local standby anesthesia so that lid height can be assessed while the patient sits upright. My surgical goal is similar to that of the authors—that is, to set the eyelid height with the patient awake, so that the eyelids just clear the visual axis and allow adequate lid closure. I encourage the authors to examine Müller's muscle more closely as they dissect aponeurosis away from it in their myogenic ptosis patients. I think they will find not only that it is infiltrated with fat, but also that it often appears much thicker than normal. I suggest dissection of Müller's away from conjunctiva in conjunction with levator aponeurosis, as it is very straightforward. Advancing the levator aponeurosis with Müller's will allow the lid to be elevated more easily and to a higher level than when just the levator aponeurosis (without Müller's) is advanced. Exposure keratopathy secondary to lagophthalmos has not been a problem in long-term follow-up (15 years) with this technique. As these dystrophies are progressive, a recurrence of ptosis can occur at some point. I estimate about a 10% recurrence rate with my technique, which is in keeping with Rodrigue and Molgat's 13% recurrence of ptosis.4Rodrigue D Molgat Y.M Surgical correction of blepharoptosis in oculopharyngeal muscular dystrophy.Neuromuscul Disord. 1997; 7: 82-84Abstract Full Text PDF Scopus (31) Google Scholar As long as they have greater than 5 mm of levator function, the technique I describe can be redone.