✓ The argon surgical laser has been used in 68 neurosurgical procedures that included the removal of intracranial and intraspinal tumors, spinal cord fenestration for syringomyelia, and the production of dorsal root entry zone lesions. Characteristics that make the argon surgical laser a useful microneurosurgical instrument include the availability of a fiberoptic delivery system, a laser spot size that can be varied continuously between 0.15 and 1.5 mm, a single laser-aiming and treatment beam, the transmission of argon laser light through aqueous media such as irrigating or cerebrospinal fluids, and improved hemostasis compared to conventional techniques. The argon laser is limited primarily by its relatively low power output (less than 16 W), which makes the excision of large tumors difficult. However, even with these limitations, which can be used to advantage in the proper setting, the authors' laboratory and clinical experience suggests that the argon surgical laser may be useful in certain microneurosurgical operations.
Stephen K. Powers, Michael S. B. Edwards, James E. Boggan, Lawrence H. Pitts, Philip H. Gutin, Yoshio Hosobuchi, John E. Adams and Charles B. Wilson
Report of 100 cases
James E. Boggan, J. Blake Tyrrell and Charles B. Wilson
✓ The development of transsphenoidal microsurgery and the refinement of endocrinological and radiological diagnostic procedures have afforded therapeutic options appropriate to the individual case in patients with hypercortisolism. The present series of 100 cases is derived from 104 patients with the diagnosis of Cushing's disease who underwent transsphenoidal pituitary exploration between 1974 and 1981. Excluding four patients in whom the pituitary gland was not exposed because of intraoperative technical difficulties, an overall cure rate of 78% was achieved. Among 71 patients with tumors confined to the sella turcica, 87% had correction of their hypercortisolism, 11% represented therapeutic failures, and one patient had tumor recurrence. In contrast, among 25 patients with extrasellar extension, correction of hypercortisolism was achieved in only 48%, 40% failed to respond, and 12% of the patients had recurrence. Four patients who failed to respond to total hypophysectomy have ectopic sources of adenocorticotropic hormone.
The results indicate that transsphenoidal microsurgical exploration for a basophilic adenoma is the procedure of choice in adults and children with Cushing's disease. The diagnostic and surgical approach to these tumors, as well as pitfalls in the transsphenoidal treatment of Cushing's disease, are discussed.
James E. Boggan, Richard L. Davis, Greg Zorman and Charles B. Wilson
✓ The authors report the uncomplicated removal of an intrasellar epidermoid cyst that on presentation mimicked a pituitary adenoma. Current controversies regarding the differentiation of this cyst from other cystic lesions of the sellar region are reviewed.
David L. LaMasters, James E. Boggan and Charles B. Wilson
✓ A presumed developmental variant of the dorsum sellae was found in a patient undergoing evaluation for a suspected pituitary adenoma. An initial computerized tomography (CT) scan suggested a suprasellar mass; however, high-resolution CT with reformations clearly revealed the mass to be the pituitary gland, which was deformed and displaced upward by an osseous spine projecting from the dorsum sellae. The radiographic appearance and etiology of this anomaly are discussed. Neurosurgeons and neuroradiologists should be aware of this anomaly when evaluating a patient for pituitary adenoma.
A review of 137 cases
David S. Baskin, James E. Boggan and Charles B. Wilson
✓ A series of 137 patients with growth hormone (GH)-secreting pituitary adenomas were treated by transsphenoidal surgery during a 10-year period. Group A comprised patients for whom this surgery was the first therapeutic intervention, and Group B included those who underwent the surgery after previous therapeutic intervention. The results were analyzed considering preoperative and postoperative endocrinological, neurological, ophthalmological, and neuroradiological data. Remission was defined as clinical response and a normal postoperative GH level, and partial remission as clinical response and postoperative reduction of the GH level by more than 50%. Any other result was considered failure. The mean follow-up period was 37.1 months; follow-up review was achieved in all the patients.
Among the 102 patients in Group A, remission was achieved in 80 (78%) patients with transsphenoidal surgery alone, and in an additional 16 (16%) after postoperative irradiation (combined response rate, 94%). All failures and patients with partial remission had preoperative GH levels of more than 50 ng/ml and suprasellar extension of the tumor. There were no deaths; 8% of patients had minor surgical morbidity; 5% had new hypopituitarism postoperatively. Of patients subsequently irradiated, 71% developed hypopituitarism.
Among the 35 patients in Group B, remission was achieved in 26 (74%), partial remission was obtained in two (6%), and seven (20%) were considered treatment failures. There were no deaths, and the morbidity rate was 14%; 66% of patients had hypopituitarism postoperatively. Of the eight patients who had received prior irradiation only, seven (88%) went into remission. All failures and partial responders had preoperative GH levels greater than 40 ng/ml; 56% had suprasellar extension. These results confirm the efficacy of the transsphenoidal approach for the treatment of GH-secreting pituitary adenomas.
James E. Boggan, Mark L. Rosenblum and Charles B. Wilson
✓ A tumor of the trochlear nerve sheath with an unusual but diagnostic presentation is described. The rarity of reported cases may reflect failure to differentiate tumors originating from the trochlear and trigeminal nerves.