Extraocular muscle surgery in a rabbit model: site of reattachment following hang-back and conventional recession.

To determine the precise site of reattachment of recessed muscles, 4-mm conventional and hang-back recessions of the inferior rectus muscle were performed in 18 albino rabbits. Six weeks later, the distance from the anterior border of the reattached muscle to the insertion was measured both grossly and microscopically. In all cases the operated muscles had advanced minimally from the site of surgical placement. Gross observation showed that the mean forward creep was significantly greater for those rabbits which underwent hang-back recession (1.81 +/- 0.67 mm) than for those that were submitted to the conventional technique (0.83 +/- 0.38 mm). Measurements done on histological sections revealed that the mean distance of the anterior border of the muscle fiber from the reference suture was larger for conventional recession (2.73 +/- 0.75 mm) than for hang-back recession (1.91 +/- 0.72 mm).