Melvin G. Alper

Combined Clinical and Computed Tomographic Diagnosis of Primary Lacrimal Fossa Lesions

We studied 39 patients who had solid mass-lesions primary in the lacrimal gland by computed tomography and reviewed their clinical histories. Twenty-three patients had either inflammatory conditions (16 cases) or lymphoid tumors (seven cases), with average symptomatic periods of less than a year. In this group, soft-tissue contour analysis in the axial and corneal projections demonstrated diffuse, compressed, and molded enlargements of the lacrimal gland in an oblong fashion, and there were no associated bone defects. Sixteen parenchymal benign or malignant tumors (six benign mixed tumors, one schwannoma, and nine malignant epithelial tumors) exhibited rounded or globular soft-tissue outlines and were frequently associated with contiguous bone changes. The benign tumors had smooth encapsulated outlines at their margins, whereas the malignant tumors displayed microserrations indicative of infiltration. The patients with the benign mixed tumors had had symptoms, on the average, for more than a year, whereas those with epithelial malignancies became symptomatic or had a preexisting benign mixed tumor that became exacerbated in periods of less than six months. Contour analysis of the soft-tissue mass depicted in coronal and axial tomograms is a valuable adjunct that leads to more accurate preoperative diagnosis when combined with a radiographic search for bone changes and the clinical history. Once a diagnosis regarding the presumptive lesional family has been made preoperatively, corticosteroid therapy may be instituted for acute inflammation and biopsies through the eyelid should be performed for suspected chronic inflammations, lymphoid lesions, or epithelial malignancies. A lateral orbitotomy without prior biopsy should be performed for rounded, well-encapsulated masses of long duration that are likely to be benign mixed tumors.

Oculomotor Nerve Regeneration After Aneurysm Surgery

A 57-year-old woman had symptoms of oculomotor nerve palsy first appearing one year before successful surgical ligation of a saccular aneurysm arising from the right posterior cerebral artery. During the subsequent postoperative period of two years, oculomotor nerve functions improved as the result of regeneration. Extensive morphometric evaluation of the regenerated nerve was compared to the normal side at the light microscopic level. The affected nerve showed a reduction in the transverse area (62%), estimated number of fibers (49%), and mean diameter of myelinated axons (23%). The normal g-ratio of axon to total diameter was almost constant at 0.64, but on the regenerated side it increased to 0.73. An increase in unmyelinated axons and connective tissue endoneurium was evident at the ultrastructural level. The significance of these marked quantitative changes was compared to the partial return of oculomotor nerve function.

Computed Tomography in Planning and Evaluating Orbital Surgery

Computed tomography (CT) scanning of the orbit has enhanced the diagnostic and surgical armamentarium of the orbital surgeon, localizing the lesion in the retrobulbar spaces and separating those expanding masses confined to the orbit from those that invade from adjacent structures. It relates an orbital lesion to the surgical spaces, optic nerve and globe, and bony orbital walls, guiding the operator in his surgical approach. If the lesion has escaped from the orbit into the intracranial cavity, CT scanning can detect it. In this way, the surgical teams and surgical approaches are chosen. After surgery, CT scanning can detect a local recurrence of a tumor and note if it has extended intracranially. However, invasion of the optic canal may be better detected by polytomography. There is also some difficulty in distinguishing between a tumor recurrence and postoperative inflammation. Postoperative follow-up evaluation by serial CT scanning every six months is advocated to determine these changes.