✓ The combination of metrizamide (Amipaque) ventriculography and vertebral angiography with stereoradiography provided precise localization of an arteriovenous malformation of the velum interpositum and an associated hematoma in the lateral ventricles that had not been detected by computerized tomography. This dual technique is recommended for precise localization of suspected intra- or periventricular lesions before surgery.
L. Dade Lunsford, Joseph C. Maroon, William O. Bank, Burton P. Drayer, and Arthur E. Rosenbaum
Ranjit K. Laha, L. Dade Lunsford, and Manuel Dujovny
✓ A 47-year-old guitar player presented with inability to use his right hand because of progressive weakness and numbness. Examination suggested compression neuropathy of the median nerve at the elbow. Exploration of the median nerve revealed compression by a tight aponeurosis of the biceps tendon. Release resulted in prompt recovery of function.
Report of two cases
L. Dade Lunsford, Joseph C. Maroon, Peter E. Sheptak, and Maurice S. Albin
✓ Two patients developed subdural tension pneumocephalus after undergoing posterior fossa surgery performed in the sitting position. The mechanism for entry of air into the intracranial compartment is analogous to the entry of air into an inverted soda-pop bottle. As the fluid pours out, air bubbles to the top of the container. We have thus referred to this as the “inverted pop-bottle syndrome.” Computerized tomography provided prompt diagnosis and confirmed brain displacement. Twist-drill aspiration of the air resulted in improvement in both patients, although one patient subsequently died from an intracerebellar hemorrhage. Tension pneumocephalus appears to be another potential complication of posterior fossa surgery in the sitting position. This condition is easily diagnosed and treated, and should be considered whenever a patient fails to recover as expected following posterior fossa surgery.
Part 2: Treatment of cervical spondylotic myelopathy in 32 cases
L. Dade Lunsford, David J. Bissonette, and David S. Zorub
✓ The results of anterior cervical surgery for treatment of cervical spondylotic myelopathy (CSM) are assessed 1 to 7 years postoperatively in 32 patients. At follow-up review, 50% were improved after surgery and 50% were unimproved or had deteriorated in spite of surgery. The results could not be statistically linked to the patients' age, duration of symptoms, severity of myelopathy, cervical canal size, or the performance of single- or multiple-level operations. Various anterior surgical techniques were used, but none proved to have superior results. The results in this series failed to surpass the results obtained by others for conservative treatment alone. In many cases, symptoms of CSM progressed despite the intervention of anterior cervical surgery.
Part 1: Treatment of lateral cervical disc herniation in 253 cases
L. Dade Lunsford, David J. Bissonette, Peter J. Jannetta, Peter E. Sheptak, and David S. Zorub
✓ Between 1971 and 1977, 334 patients at the Presbyterian-University Hospital underwent anterior surgery for treatment of hard or soft cervical disc herniation. Of these patients, 295 had radicular symptoms only. This retrospective study details the results of anterior cervical surgery for treatment of lateral disc herniation in 253 patients who survived 1 to 7 years postoperatively. Sixty-seven percent had excellent or good results. Although 77% initially noted complete relief of symptoms after surgery, 38% subsequently developed one or more recurrent symptoms at some time during the follow-up period. The overall results of surgery for soft disc cases were no different from the results for hard discs, although significantly more hard disc cases required postoperative conservative treatment. The results of surgery after anterior fusion were no different than the results after anterior discectomy alone. However, overall postoperative complications were more frequent and hospitalizations were longer in the patients who underwent fusion. Patients with multiple-level surgery had statistically similar results to those with single-level surgery. None of the nine preoperative clinical features reported by others to influence the results of anterior cervical surgery were found to consistently affect outcome in the present series.
L. Dade Lunsford, Geoffrey Levine, and Lewis W. Gumerman
✓ The dosimetry of radioactive phosphorus (32P) for intracavitary treatment of cystic brain tumors is dependent upon accurate determination of the cyst volume. The authors have used both high-resolution computerized tomography (CT) scanning and an isotope dilution technique with technetium-99m (99mTc) sulfur colloid to determine cyst volumes in an experimental model and in six patients with intracerebral cystic tumors. In six separate comparisons using an experimental phantom “cyst,” no significant differences between CT and 99mTc values were detected. In six patients with cystic neoplasms varying from 3 to 6.7 ml in volume, the percent differences between values obtained by CT and isotope dilution ranged from −17.26% to +13.13%. In individual patients, these differences proved to be of little significance for planning dosimetry. In both experimental and clinical trials comparing isotope dilution and CT measurement techniques, the CT technique using the standard software of the scanner and 5-mm thick slices proved to be a highly accurate method of determining cyst volume. The authors now base dosimetric calculations for intracavitary radiation with 32P on CT technique alone.
L. Dade Lunsford, A. Julio Martinez, and Richard E. Latchaw
✓ Modern stereotaxic surgery is dependent upon compatible advanced imaging tools, including computerized tomography (CT) scanning and magnetic resonance (MR) imaging. The authors describe three cases in which the patients underwent stereotaxic surgery for mass lesions identified by both MR imaging and CT scans. Identical target coordinates were defined by both techniques, and accuracy was confirmed by intraoperative CT. In comparison to stereotaxic CT, MR provided superior contrast resolution, allowed direct multiplanar imaging and target determination, and permitted accurate correlation of the image with histological features. The operative set-up and technique are described. Stereotaxic surgery with MR imaging may permit more accurate histopathological definition of tumor margins and ultimately lead to better dosimetry for therapeutic procedures such as interstitial brachytherapy.
An 11-year experience in the CT era
Walter A. Hall and L. Dade Lunsford
✓ Since computerized tomography (CT) scanning became available at the University Health Center of Pittsburgh in July, 1975, 17 patients have undergone removal of colloid cysts of the third ventricle by transfrontal, transcallosal, or stereotaxic surgery. All patients presented with symptoms and signs of increased intracranial pressure; CT scanning proved to be the best neurodiagnostic test to define the colloid cysts. Since the development of CT-guided stereotaxic surgery, the authors have preferentially performed stereotaxic aspiration in seven patients; three of these subsequently required craniotomies to remove residual cysts producing persistent symptoms. The viscosity of the intracystic colloid material and/or displacement of the cyst away from the aspiration needle were reasons for unsuccessful aspiration; the CT appearance did not correlate with the ability to aspirate the lesion by the stereotaxic technique. Postoperative patency of the ventricular system was documented by intraoperative CT ventriculography performed during stereotaxic surgery. Removal of the cyst wall was not necessary. Because of the low associated morbidity rate, percutaneous stereotaxic aspiration is recommended as the initial treatment of choice for colloid cysts of the third ventricle. If stereotaxic aspiration fails and symptoms persist, craniotomy should be performed.
Ian F. Pollack, L. Dade Lunsford, Thomas L. Slamovits, Lewis W. Gumerman, Geoffrey Levine, and Alan G. Robinson
✓ Stereotaxic intracavitary irradiation with instillation of phosphorus-32 (32P) colloidal chromic phosphate was performed in nine patients with cystic craniopharyngiomas. Serial neurological, ophthalmological, neuroendocrinological, and radiological examinations were performed before and after treatment. Dosimetry was determined based on a computerized tomography (CT) estimation of tumor volume, and was calculated to provide a tumoricidal dose (200 to 300 Gy) to the cyst wall. The follow-up period ranged from 14 to 45 months (mean 27 months). After treatment, all nine patients showed improvement of symptoms and radiological evidence of cyst regression. Because of an expanding solid component producing recurrent symptoms, one patient required a craniotomy 14 months after isotope instillation. Three of five patients with impaired visual acuity before surgery had significant improvement in acuity after treatment. Preoperative visual field defects in eight patients improved in four after 32P therapy. Of seven patients with preoperative endocrine abnormalities, one individual showed almost complete normalization and another had improvement in endocrine function. Patients who exhibited residual neuroendocrine function before isotope instillation developed no significant deterioration in endocrine status during the follow-up period. The findings suggest that stereotaxic intracavitary irradiation is a safe and effective treatment which should be considered as the initial surgery for cystic craniopharyngiomas.