Robert J. Coffey

Radiosurgery of acoustic neurinomas.

Eighty‐five patients with acoustic neurinomas underwent stereotactic radiosurgery with the gamma unit at the University of Pittsburgh (Pittsburgh, PA) during its first 30 months of operation. Neuroimaging studies performed in 40 patients with more than 1 year follow‐up showed that tumors were smaller in 22 (55%), unchanged in 17 (43%), and larger in one (2%). The 2‐year actuarial rates for preservation of useful hearing and any hearing were 46% and 62%, respectively. Previously undetected neuropathies of the trigeminal (n = 12) and facial nerves (n = 14) occurred 1 week to 1 year after radiosurgery (median, 7 and 6 months, respectively), and improved at median intervals of 13 and 8 months, respectively, after onset. Hearing loss was significantly associated with increasing average tumor diameter (P = 0.04). No deterioration of any cranial nerve function has yet developed in seven patients with average tumor diameters less than 10 mm. Radiosurgery is an important treatment alternative for selected acoustic neurinoma patients.

Gamma knife radiosurgery of meningiomas

Fifty patients with meningiomas were treated during the initial 30 months experience using the 201 source cobalt-60 gamma knife at the University of Pittsburgh. The most frequent site of origin was the skull base. Stereotactic radiosurgery was the primary treatment modality in 16 (32%) patients with symptomatic tumors demonstrated by neuroimaging. Thirty-six patients (72%) had undergone at least one craniotomy, and 4 patients (8%) previously had fractionated external beam radiation therapy. The proximity of cranial nerves, vascular, pituitary and brainstem structures to the often convoluted tumor mass was crucial to dose selection. Follow-up imaging studies and clinical analysis of patients were performed at 6-month intervals. The actuarial 2-year tumor control rate was 96%. Only 2 patients have shown delayed tumor growth outside the radiosurgical treatment volume. To date, stereotactic radiosurgery proved to be a relatively safe and effective therapy for selected patients with symptomatic meningiomas, either as an adjuvant treatment to prior resection, or as a primary treatment alternative for patients whose advanced age, medical condition or high-risk tumor location mitigated against surgical resection.

Stereotactic radiosurgery of small intracranial tumors: Neuropathological correlation in three patients

The mechanism by which radiosurgery can stop the growth of some tumors is poorly understood, in part because postmortem neuropathological findings in patients have been reported only rarely. To define further the effects of radiosurgery, we present the correlation among clinical, neuroimaging, and neuropathological data in three patients with different intracranial tumors who died between 2 and 39 weeks after radiosurgery. The target volumes in two patients with malignant tumors showed sharply demarcated coagulative necrosis. In the third patient, who had a benign acoustic nerve tumor, neuropathological examination found intratumoral hemorrhage and cyst formation, but no necrosis. Radiosurgery appears to cause acute necrosis of malignant cells, although its effectiveness may be limited by the infiltrative nature of some tumors. In benign tumors, necrosis following radiosurgery is relatively delayed, and may not be required for growth arrest.

Familial trigeminal neuralgia and charcot-marie-tooth neuropathy

Typical trigeminal neuralgia has occasionally occurred in multiple members of the same family over several generations. The clinical features of such cases, including the increased incidence in females, and the absence of other apparent hereditary, neurologic, metabolic, or structural abnormalities were identical to those of sporadic cases. More rarely, familial trigeminal neuralgia has been described in the setting of hereditary peripheral neuropathy, especially Charcot-Marie-Tooth disease. We describe patients from two different families with Charcot-Marie-Tooth disease and medically intractable trigeminal neuralgia. Both patients were successfully treated by percutaneous retrogasserian glycerol rhizolysis. The occurrence of cranial nerve symptoms in patients with demyelinating peripheral neuropathies is discussed in light of the current hypotheses regarding the etiology of trigeminal neuralgia.

Image-Guided Stereotactic Surgery: A 10-year Evolutionary Experience

The recent revolution in medical imaging has demanded concurrent development of sophisticated and compatible stereotactic guiding devices in order to diagnose or treat mass lesions on the brain and disorders of cerebral physiology. Between July 1, 1979, and July 1, 1989, 1,006 patients underwent image-guided stereotactic surgery at the University of Pittsburgh. During this 10-year interval the first dedicated computed tomography stereotactic operating room and the first North American radiosurgical suite containing a 201 60Co source gamma knife were constructed. Early in our experience, 60.5% of the patients underwent diagnostic (biopsy) stereotactic surgery whereas, by 1988, 77.8% of the patients underwent therapeutic stereotactic surgery. At our institution, stereotactic surgery was performed last year in 257 patients, representing 19.9% of all neurosurgical operations. During the past 10 years, stereotactic surgery has developed an integral and definitive role in contemporary mainstream neurosurgery. Across the world stereotactic technology is now widely available. In the future increasing emphasis will be placed on therapy, image integration, computer software development, and new instrumentation designed to meet the evolving needs of neurological surgeons who demand safe, precise, and effective tools to explore the brain.

Hypothalamic and basal forebrain germinoma presenting with amnesia and hyperphagia

Patients harboring primary intracranial germinomas usually have had Parinauds syndrome and hydrocephalus (with pineal tumors) or hypopituitarism, visual loss, and diabetes insipidus (with suprasellar tumors) at presentation. The few reported cases of verified intraparenchymal hypothalamic germinomas all have been in prepubertal males with progressive neurologic deficits, altered levels of consciousness, or clinically apparent panhypopituitarism. The subject of this report was an endocrinologically normal, primiparous 24-year-old woman who presented with hydrocephalus followed by worsening anterograde amnesia and hyperphagia despite having a functioning ventriculoatrial shunt. Computed tomography scanning and magnetic resonance imaging demonstrated an anterior hypothalamic, thalamic, and basal forebrain mass, which stereotactic biopsy proved to be a germinoma. Intraaxial germinomas restricted to the anterior hypothalamus or thalamus rarely have been reported. The clinical features of the current patient may be unique.

Supracallosal interhemispheric arachnoid cyst: Resolution after intracystic hemorrhage and infection

A case of a large, symptomatic, supracallosal interhemispheric arachnoid cyst is presented. Positive contrast-enhanced computed tomographic (CT) cystography after stereotactic puncture and aspiration demonstrated lack of communication between the cyst and the subarachnoid space or ventricular system. A cystoperitoneal shunt was successful in relieving the patients symptoms for 5 years. A delayed shunt infection after gynecologic surgery necessitated removal of the shunt, and was complicated by asymptomatic intracystic hemorrhage. Thereafter, serial CT and magnetic resonance imaging scans showed eventual disappearance of the cyst.

Stereotactic Gamma Radiosurgery for Intracranial Vascular Malformations and Tumors: Report of the Initial North American Experience in 331 Patients

We reviewed the initial experience with 331 consecutive patients treated during the first 2 years of operation of the University of Pittsburgh Gamma Unit. Among 178 patients with vascular malformations, 161 had angiographically demonstrable arteriovenous malformations, and 17 had angiographically occult malformations. Patients with tumors included 123 with histologically benign, predominantly extra-axial neoplasms and 30 with malignant, predominantly intra-axial neoplasms. When the arteriovenous malformation nidus could be covered with at least the 50% isodose line and a dose to the margin greater than or equal to 20 Gy, 60% were obliterated within 1 year. Patients with benign tumors and well-circumscribed malignant tumors did not experience tumor growth within the radiosurgical treatment volume. The role of radiosurgery is expanding to include primary treatment of larger lesions than was formerly possible and adjunctive treatment of more complex arteriovenous malformation and tumors.

Animal research stereotactic instrument modified for computed tomographic guidance

While target localization for human stereotactic surgery has been refined by computed tomographic (CT) and magnetic resonance imaging (MRI), stereotaxis in experimental animals has remained dependent upon external cranial landmarks and standardized atlas coordinates. To overcome the limitations and inaccuracies of animal devices using the original Horsley-Clarke method, we modified a standard animal stereotactic instrument in order to make target localization and coordinate determination possible with CT imaging. Although the device can be adapted to any medium-sized animal species, we demonstrate its use with dogs here.

Factors Determining Survival of Patients with Malignant Gliomas Diagnosed by Stereotactic Biopsy

We analyzed the prognostic significance of tumor histology, location, treatment, and selected clinical features at presentation in 91 consecutive patients with malignant gliomas diagnosed by stereotactic biopsy. In 64 patients with glioblastoma multiforme (GBM) the following factors were associated with longer survival: lobar tumor location, adequate radiation therapy (RT) tumor dose 5,000-6,000 cGy, Karnofsky performance rating (KPR) at presentation greater than or equal to 70, and a normal level of consciousness before biopsy. In 27 patients with anaplastic astrocytoma, factors associated with longer survival were lobar tumor location, adequate RT, age less than 40 years at presentation, and a history of seizures. Delayed cytoreductive surgery in lobar GBM extended median survival but did not improve long-term survival. For patients with deep or midline malignant gliomas and for selected patients with lobar tumors, stereotactic biopsy followed by RT may be the most reasonable initial treatment strategy.