Neurosurgical involvement in tumors of the orbit.

The neurosurgeon has a great deal to offer in the therapy of orbital tumors. Dr. Dandy's supposition that all orbital tumors could be approached by the intracranial route is certainly correct, but technical advances have made the medial and lateral approaches to the orbit more useful for most tumors which are confined to the orbit (22, 25). For those which involve the posterior orbit and canal and have intracranial extensions, the intracranial approach is excellent. Since Dandy's first description of the procedure in 1922, there have been 29 patient reports concerning the results of transcranial canalicular decompression for non-traumatic causes. The most common diagnosis was meningioma (15), and other tumor diagnoses were fibrous dysplasia (7) and hemangioma (2). One-third of the patients were improved; one-third had vision stabilized; and one-third were made worse by surgery. Modern techniques with the microscope and high speed drill have greatly improved these results. Our own experience in the decompression of 15 canals in 11 patients is as follows. There were six patients with meningioma, and two were bilateral. Three patients were found to have a vascular dolichoectasis and one patient had an hemangioma, and in two patients no compression was identified. Immediately postoperatively, two-thirds of the patients were improved, and only one eye (representing 6.7% of the nerves decompressed) was worsened. This resulted from an attempt to totally remove an adherent sheath meningioma. Long-term follow-up median 34 months has demonstrated maintenance of these gains. Eighty percent of the patients have improved or remained stable. These data indicate that the procedure described can be done safely without major risk of visual loss. The neurosurgeon should play an increasingly important role in the evaluation and therapy of posteriorly placed orbital tumors and unexplained compressive optic neuropathy.