The removal of the deep lateral wall in orbital decompression: its contribution to exophthalmos reduction and influence on consecutive diplopia.

Purpose: To evaluate the contribution of maximal removal of the deep lateral wall of the orbit to exophthalmos reduction in Graves' orbitopathy and its influence on the onset of consecutive diplopia.

Design: Case-control study.

Methods: The medical records of two cohorts of patients affected by Graves' orbitopathy with exophthalmos > or = 23 mm, without preoperative diplopia, were retrieved at random from the pool of patients decompressed for rehabilitative reasons at our institution (01/1990 to 12/2003), and retrospectively reviewed. They had been treated with an extended (cases, group 1, n = 15) or conservative (controls, group 2, n = 15) 3-wall orbital decompression performed through a coronal approach. The deep portion of the lateral wall had been removed in the extended decompression group while preserved in the conservative decompression group. Demographics, preoperative characteristics, and surgical outcome were compared. The difference in mean exophthalmos reduction between groups 1 and 2 was considered to be the contribution of the deep lateral wall to reduction of exophthalmos.

Results: Groups 1 and 2 were drawn from a pool of 37 and 335 patients, respectively. Demographics and preoperative characteristics of the two groups were not significantly different. The mean contribution of the deep lateral wall to exophthalmos reduction was 2.3 mm. The onset of consecutive diplopia was not significantly different between the two groups (case n = 2/15, controls n = 5/15; P = .203). Diplopia resolved spontaneously in all the patients of group 1, while all the patients of group 2 required surgery.

Conclusions: Removal of the deep lateral orbital wall as part of a coronal-approach, 3-wall decompression, enhances the degree of exophthalmos reduction without increasing the risk of consecutive diplopia.