Blepharoptosis is a common source of visual and functional impairment. Conjunctivo-müllerectomy was first described by Putterman and Urist in 1975, and since then other authors have reported surgical techniques and additional mechanisms to shorten the posterior lamella and consequently raise the eyelid.1,6 Treatment of eyelid ptosis is one of the greatest challenges of oculoplastic surgery because it results inlow predictable surgical results. The conjunctivo-müllerectomy technique has an advantage of greater predictability in eyelid height in the postoperative period of ptosis of up to 2 mm, according to its pre-established surgical schedule and the 10% phenylephrine test.
However, in the present study it was observed that the technique presents satisfactory results even for ptosis greater than 2 mm, provided that there is a good response to the phenylephrine test, since none of the patients needed to be reoperated.
If Müller’s muscle is responsible for only 2 mm raising, it is hypothesized that other structures such as UELM may also be removed in this technique. However, none of our samples identified UELM striated muscle fibers, i.e. there was no shortening of UELM in these results.
A compelling theory about the efficiency of conjunctivo-mullerectomy was suggested by Dresner, who proposed that posterior lamella excision had the additional effect of aponeurosis plication of the posterior upper eyelid levator muscle.5,6
In a more recent study, Marcet et al. performed the conjunctivo-mullerectomy procedure on one of the 8 cadavers’ upper eyelids using the contralateral upper eyelid as a control. The orbitals were then bilaterally exenterated and histopathological analysis was performed. It was observed that the upper eyelid levator muscle aponeurosis is plicated on the upper eyelids of the patients undergoing the surgery in question. The authors concluded that blepharoptosis was relieved by posterior lamella shortening and internal advancement of upper eyelid levator muscle aponeurosis.7
These theories could explain why there was surgical success with conjunctivo-müllerectomy even in patients with ptosis greater than 2 mm; a result achieved in the patient population of the present study. UELM may have been closer to the superior tarsal plate.
Maheshwari concluded that patients presenting ptosis with good response to the phenylephrine test associated or not to good UELM function, also had a satisfactory surgical result.5 In contrast, patients with good response to phenylephrine test, good Miller function, but poor UELM function (less than 5 mm), the surgery technique proposed should involve resection of the tissue above Whitnall’s ligament, in order to assure UELM plication to the tarsal plate and satisfactory correction.5
In our clinical practice, we experienced substantial results performing traditional conjunctivo-müllerectomy with muscle resection below Whitnall’s ligament (between 8-10 mm) in patients treated for ptosis with positive response to the phenylephrine instillation and poor UELM function. Histopathological analysis from excised tissue presented only smooth muscle sample, confirming the absence of striated muscle. Therefore, we suppose that even in these cases, the mechanism of UELM plication to the tarsal plate may occur as well, resulting in upper eyelid elevation and clinical improvement.
On the other hand, in one single study in the literature, by Kakizaki et al., the upper eyelid levator muscle is formed by 2 lamellae, with the anterior one being composed by striated musculature and the posterior one by smooth muscle.8 Our samples identified only smooth muscle, and could be from Müller’s muscle as well as this posterior lamella from levator muscle. Thus, the success of conjunctivo-müllerectomy in any magnitude of involutional ptosis responsive to the 10% phenylephrine test can be explained by removing the posterior lamella of the upper eyelid levator muscle, in addition to Müller’s muscle.
Further studies need to be performed until the efficiency of conjunctivo-müllerectomy for involutional ptosis of any magnitude responsive to the 10% phenylephrine test is proven.