The cynomolgus monkey as a model for orbital research. II. Anatomic effects of lateral orbitotomy.

In order to assess the anatomic consequences of lateral orbitotomy in a disease-free muscle cone, a technique of microsurgical exposure of the ciliary ganglion in the cynomolgus monkey was formulated. Animals were sacrificed at 2 and 6 months following surgery, and microscopic sections of the whole orbit prepared and compared to sections taken from the non-operated contralateral orbits. Findings at two months were: periorbital thickening and hypercellularity along with osteoneogenesis at sites remote from the surgery, particularly the superior-lateral orbit, and lack of appreciable scar formation in the fat of the muscle cone itself. The thickened periorbita persisted at six months, although remodeling of the bone had largely restored the normal appearance of the orbital walls. These findings may possibly explain the restrictive myopathy sometimes seen following surgical and traumatic disruption of the bony orbit.