Endoscopic orbital decompression with preservation of an inferomedial bony strut: minimization of postoperative diplopia.

With the increasing sophistication and safety of endoscopic orbital decompression, the technique is seen by many as an attractive and less morbid alternative to traditional open techniques. This rationale also makes the procedure more acceptable for individuals considering decompression for cosmetic reasons. As a result, complications such as postoperative diplopia assume greater significance. Preservation of an inferomedial bony strut has been postulated to reduce the incidence of postoperative diplopia in transconjunctival, but not endoscopic, orbital decompression for dysthyroid ophthalmopathy. We present a consecutive series of 11 subjects (21 eyes) who underwent transnasal endoscopic medial and inferior decompression of the orbits bilaterally. All patient charts were reviewed in a retrospective fashion and ophthalmologic, surgical, and cosmetic data were recorded, with callback of patients with incomplete data sets. All cases were performed under general anaesthesia. Preservation of the strut was possible in 15 of 21 eyes. Visual acuity was preserved or improved in all 21 eyes. Average ocular recession based on Hertel measurements was 3.6 mm and there were no surgical complications. New-onset or worsening diplopia was noted postoperatively in 2 of 11 subjects. However, in patients where both struts were preserved, there was zero incidence of postoperative diplopia (0/6). These results indicate that preservation of an inferomedial bony strut is not only technically feasible but also does not compromise the adequacy of decompression. The results also suggest that preservation of the inferomedial bony strut during endoscopic orbital decompression can reduce the incidence of postoperative diplopia.