Success of the Fasanella-Servat operation independent of Müller's smooth muscle excision.

In an attempt to elucidate the mechanism whereby the Fasanella-Servat operation corrects ptosis, the authors examined the histopathologic features of 40 consecutive surgical specimens from 37 patients. Because all specimens contained tarsus, this tissue was graded into two groups according to vertical height: (1) minimal (30%) and (2) moderate (70%). Müller's smooth muscle was graded into four groups: (1) absent to negligible (42.5%); (2) minimal (45%); (3) moderate (10%); and (4) large (2.5%). Levator aponeurosis was absent, and conjunctive was present, in all resections. Accessory lacrimal gland tissue was present in 42.5% of cases and did not cause decreased tear production. Although 87.5% of cases had absent to minimal smooth muscle resections, these patients had equally successful results in comparison to patients with moderate to large amounts of smooth muscle resections. Based on these data, the authors have concluded that the effectiveness of the Fasanella-Servat operation does not depend on a Müllerectomy, but instead is probably due to a combination of other factors: (1) a vertical posterior lamellar shortening; (2) secondary contractile cicatrization of the wound; and (3) plication or advancement of the Müller's smooth muscle-levator aponeurosis complex on the tarsus.