Muller’s muscle conjunctival resection (MMCR) For Ptosis
Müller’s muscle (MM) is a sympathetically innervated upper eyelid muscle that, together with the levator palpebral superioris, elevates the eyelid. The MM resembles smooth muscle, and originates from the levator aponeurosis about 15 mm above the superior tarsus. The MM is adherent to the conjunctiva but easily separable from the levator aponeurosis, and is enclosed in a vascular sheath. The lifting effect of the MM is best demonstrated clinically by the improvement of some ptotic eyelids upon stimulation with phenylephrine (PE) eye drops (‘PE test’). MM conjunctival resection (MMCR), originally described by Fasanella and Servat1 and later modified by Putterman and Urist,2 has traditionally been performed for correction of mild to moderate upper eyelid ptosis, resulting in improved eyelid height. It is thought that eyelid elevation is achieved by vertical shortening of the posterior lamella, plication or advancement of the MM, and levator aponeurosis and cicatricial changes. The definitive mechanism is still a matter of controversy. The only systematic histopathological study of a large series of excised specimens that might elucidate the mechanisms whereby this operation corrects ptosis was performed by Buckman et al3 who used qualitative measures to grade the amount of tarsus in the specimen and the amount of smooth muscle. This report describes a novel technique for quantitatively measuring the precise amount of resected MM and demonstrates the effect of the amount of measured tissue on the outcome of the MMCR procedures.
Müller’s muscle conjunctival resection (MMCR) is traditionally performed in patients with mild ptosis who show eyelid elevation following instillation of topical phenylephrine. In 1961 Fasanella and Servat described a procedure for patients with minimal blepharoptosis in which they applied two curved haemostats to the everted superior tarsus, ran a suture above them, and excised the tissues held by them. They initially described a “resection of Müller’s muscle, levator, tarsus and conjunctiva”, however histological studies have since shown that tissue resected consisted of a predominately tarsoconjunctival layer . We now regard the Fasanella-Servat procedure, which involves a blind approach, as a predominately tarsoconjunctival resection.