William A. Shucart

Transcallosal approach to the anterior ventricular system.

Using an anterior transcallosal approach, we operated upon 25 patients with lateral and 3rd ventricular lesions. The facility of this route is discussed, and the operative technique is presented.

Endoscopic Sphenoidotomy Approach to the Sella

OBJECTIVE Advances in optics, miniaturization, and endoscopic instrumentation have revolutionized surgery in the past decade. We report our experience with the endoscope in nine patients with sellar lesions who underwent an endoscopic sphenoidotomy approach to the sella. METHODS An endoscopic transnasal cavity sphenoidotomy approach without a septal dissection was used in the resection of pituitary adenomas and other sellar lesions. RESULTS This approach provided excellent exposure of the sella and adequate working space. The technique produces less postoperative pain and, in some cases, shortens hospital stay. The sphenoidotomy approach eliminates the problems of lip numbness, septal perforations, and oronasal fistulas. CONCLUSION The endoscopic sphenoidotomy approach has become our preferred approach to sellar lesions.

Temozolomide in the treatment of an invasive prolactinoma resistant to dopamine agonists

Prolactinomas are common tumors of the anterior pituitary gland. While conventional therapies, including dopamine agonists, transsphenoidal surgery and radiotherapy, are usually effective in controlling tumor growth, some patients develop treatment-resistant tumors. In this report, we describe a patient with an invasive prolactinoma resistant to conventional therapy that responded to the administration of the alkylating agent, temozolomide.

Determination of the 4 mm Gamma Knife helmet relative output factor using a variety of detectors.

Though the 4 mm Gamma Knife helmet is used routinely, there is disagreement in the Gamma Knife users community on the value of the 4 mm helmet relative output factor. A range of relative output factors is used, and this variation may impair observations of dose response and optimization of prescribed dose. To study this variation, measurements were performed using the following radiation detectors: silicon diode, diamond detector, radiographic film, radiochromic film, and TLD cubes. To facilitate positioning of the silicon diode and diamond detector, a three-dimensional translation micrometer was used to iteratively determine the position of maximum detector response. Positioning of the films and TLDs was accomplished by manufacturing custom holders for each technique. Results from all five measurement techniques indicate that the 4 mm helmet relative output factor is 0.868 +/- 0.014. Within the experimental uncertainties, this value is in good agreement with results obtained by other investigators using diverse techniques.

De Novo Development of an Aneurysm: Case Report

A case of the de novo formation of an aneurysm in a young woman is presented. At age 13 years, she had a spontaneous subarachnoid hemorrhage. Cerebral angiography showed an aneurysm of the bifurcation of the left internal carotid artery and a small aneurysm of the left anterior choroidal artery. At surgery, the aneurysm of the internal carotid artery was clipped, and the aneurysm of the left anterior choroidal artery was wrapped with muslin. Thirteen years later, the patient had another subarachnoid hemorrhage. Cerebral arteriography showed four aneurysms that had developed at previously angiographically normal sites. This case suggests that young patients with aneurysms might benefit from follow-up angiography in search of late aneurysm formation.

Temporary balloon occlusion of a proximal vessel as an aid to clipping aneurysms of the basilar and paraclinoid internal carotid arteries: technical note.

One aneurysm of the basilar artery and three large, paraclinoid aneurysms of the internal carotid artery (ICA) were treated with the aid of intraoperative temporary balloon occlusion of the vessel. Optimal clip placement was confirmed using intraoperative angiography. This technique provided excellent proximal vascular control and for the large aneurysms of the paraclinoid ICA obviated the need for surgical exposure of the ICA in the neck. We think this is a useful adjunct in the surgical management of aneurysms of both the basilar artery and proximal ICA.

Listeria monocytogenes Brain abscess or meningoencephalitis

A brain abscess caused by Listeria monocytogenes developed in an immunosuppressed renal transplant patient. Meningitis and meningoencephalitis from this organism were encountered in three other renal transplant recipients at this medical center during the past 4 years. Focal neurologic deficits occurred in patients with either Listeria abscess or meningoencephalitis. Computerized tomography was a rapid aid to the diagnosis of abscess. Immunosuppression has increased the incidence of central nervous system Listeria infections, but ampicillin still provides effective treatment, even when immunosuppressive therapy is continued. Limited experience with Listeria brain abscess suggests that surgical intervention improves the prognosis.

Experimental negative intraventricular pressures

Negative intracranial pressures are known to occur normally in man and animals in the upright position [3, 71. Pathological conditions associated with increased intracranial pressure may alter this, but there is still a decrease in intracranial pressure with elevation of the head. Attention has recently been drawn to the fact that CSF shunt systems may cause negative intracranial pressure significantly greater than that which occurs normally [5, 8, 91. We have documented that this can occur in animals. It is often assumed that the intraventricular pressure in a shunted patient is maintained at or near the closing pressure of the valve used in the system [2]. Other hydrostatic factors such as position of the patient and particularly the length of tubing from the cerebral ventricles to the heart, pleural cavity, or peritoneal cavity have been ignored. With the increasing use of ventriculo-peritoneal shunts with long distal tubes these factors require more consideration. We initially developed an

Preoperative arteriographic spasm and outcome from aneurysm operation.

The timing of intracranial operation for the treatment of ruptured cerebral aneurysm remains controversial. To find objective parameters to guide us, we performed angiography 24 to 72 hours before contemplated operation in 35 Grade I patients in whom subarachnoid hemorrhage had occurred at least 1 week earlier. Operation in the presence of angiographic vasospasm in Grade I patients over 1 week after SAH was associated with increased morbidity and mortality rates. Only 1 of 28 patients in whom spasm was absent or mild at the time of operation had an unsatisfactory outcome from operation (P less than 0.003). There was no correlation between clinical grade and significant spasm; 17 patients who were clinically Grade I over 1 week after SAH had moderate or severe angiographic spasm. These data suggest that all patients should undergo angiography just before contemplated operation and that operation should be postponed if vasospasm is present.

Delayed chiasmal decompression after transsphenoidal operation for a pituitary adenoma

A patient with a large pituitary adenoma and visual field loss showed no significant change 6 weeks after transsphenoidal operation, but marked and abrupt improvement occurred at 10 weeks. The implications of this delayed improvement are discussed.