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.

A proposed classification for spinal and cranial dural arteriovenous fistulous malformations and implications for treatment.

A classification is proposed that unifies and organizes spinal and cranial dural arteriovenous fistulous malformations (AVFMs) into three types based upon their anatomical similarities. Type I dural AVFMs drain directly into dural venous sinuses or meningeal veins. Type II malformations drain into dural sinuses or meningeal veins but also have retrograde drainage into subarachnoid veins. Type III malformations drain into subarachnoid veins and do not have dural sinus or meningeal venous drainage. The arterial supply in each of these three types is derived from meningeal arteries. The anatomical basis of the proposed classification is presented with several cases that illustrate the three types of dural AVFMs. A rationale for the treatment of spinal and cranial dural AVFMs according to their anatomical characteristics is discussed.

Respiratory dysfunction associated with traumatic injury to the central nervous system.

Pulmonary dysfunction is a common complication of head trauma and spinal cord injury. Abnormal breathing patterns reflect the influence of altered neural integration. Early arterial hypoxemia can result from ventilation-perfusion mismatching, microatelectasis, aspiration, fat embolism, or the development of the adult respiratory distress syndrome. Significant changes in lung volumes, ventilation, and gas exchange can occur in spinal cord injury as a result of the loss of diaphramatic or intercostal muscle function. Recruitment of accessory respiratory muscles plays an important role in stabilizing the rib cage and improving expiratory function. Strength training improves expiratory muscle function in quadriplegics and should be continued indefinitely. Most importantly, survival of patients with CNS injuries improves with meticulous and vigorous pulmonary hygiene. The pulmonary hygiene program should include regular changes in the patient's position, assisted coughing and deep breathing exercises, incentive spirometer, bronchodilators, fiberoptic bronchoscopy when indicated, and frequent monitoring of pulmonary mechanics. Long-term survival of the patient with head trauma or spinal cord injury is correlated to successful weaning from mechanical ventilation. Various forms of mechanical ventilator support can be adopted for the patient's ventilatory needs, and many patients will achieve some degree of freedom from mechanical ventilation. Newer ventilatory assist devices that do not require tracheostomy should be considered.

Enlargement of basilar artery aneurysms following balloon occlusion--"water-hammer effect". Report of two cases.

Two patients with distal basilar aneurysms were treated with intra-aneurysmal balloon occlusion. After apparently successful therapy, follow-up angiograms demonstrated aneurysm enlargement with balloon migration distally in the sac. Geometric mismatch between the base of the balloons and the aneurysm neck together with transmitted pulsation through the 2-hydroxyl-ethylmethacrylate (HEMA)-filled balloon directly contributed to aneurysm enlargement. In this report, the authors discuss the problems of progressive aneurysm enlargement due to a "water-hammer effect" and the possibility of hemorrhage following subtotal occlusion.

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.

Hyponatremia in neurosurgical patients.

Hyponatremia is the most common electrolyte disturbance seen in a neurosurgical ICU. The most common cause is impaired excretion of water, which may be due to many causes. The hyponatremia itself is of importance only because of its effect on ECF osmolality, which, when low, causes cellular swelling and dysfunction. While a low serum sodium is most commonly associated with an increased ECF, it may also be associated with a normal or low ECF. In any of these situations, however, the symptomatology will be the same. On the other hand, the examination of the patient and the laboratory examinations will help in determining whether it is an instance of overhydration or underhydration. The urgency and type of treatment are dictated by the severity of the patient's symptoms.

Intradural spinal lipomas.

Intradural spinal lipomas are rare, and their origin is unknown. Although the clinical presentation may not be distinctive, the neuroradiographic presentation is. Total excision is usually not possible, although subtotal resection is easily accomplished using an ultrasonic aspirator.

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.

The isolation and characterization of Ca++-accumulating subcellular membrane fractions from cerebral arteries.

A study was undertaken using differential centrifugation methods to isolate from rabbit cerebral arteries the subcellular microsomal protein fractions capable of actively sequestering Ca++. One isolated protein fraction displayed a relatively large adenosine triphosphate (ATP)-dependent Ca++-accumulating capacity that was completely inhibited by NaN3, and was therefore designated the "mitochondrial fraction." Electron microscopy confirmed that this fraction consisted of numerous mitochondrial elements. Another isolated membrane fraction possessed a Ca++-accumulating capacity dependent on ATP and oxalate and only partially sensitive to NaN3. In the presence of mersalyl acid or the Ca++ ionophore, A23187, Ca++ uptake by this fraction was inhibited 98.0% and 87.4%, respectively. Electron microscopy revealed that this fraction consisted of numerous membrane vesicles, and measurements of Na+-K+-ATPase (adenosine triphosphatase) activity indicated minimal plasma membrane contamination. It was concluded that this microsomal fraction consisted primarily of sarcoplasmic reticulum. At physiological free [Ca++] levels, Ca++ uptake by this fraction was inhibited by norepinephrine through a process sensitive to tolazoline but not propranolol. The effects on Ca++ uptake of added cyclic adenosine monophosphate (cAMP) alone or with rabbit or bovine protein kinase were inconclusive. The organic Ca++ channel blockers, nifedipine and verapamil, significantly inhibited Ca++ uptake by sarcoplasmic reticulum.

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.

Epsilon-aminocaproic acid and recurrent subarachnoid hemorrhage: a clinical trial.

A clinical trial of epsilon-aminocaproic acid (EACA) in preventing recurrent hemorrhage from intracranial arterial aneurysms is reported. Previous reports were reviewed, and their results concerning antifibrinolytic agents were inconclusive in establishing their efficacy. One hundred patients with documented ruptured intracranial aneurysms were admitted to this study within 48 hours of the initial hemorrhage: 45 patients received 36 gm of EACA/day, with 11 documented rebleeds and one suspected rebleed. No benefit was seen from the use of EACA.

Lateral approach to the upper cervical spine.

A procedure for access to the ventral portion of the spinal canal from the foramen magnum to the superior portion of C-3 is described. This is useful for lesions that are primarily ventral or ventrolateral to the spinal cord, such as meningiomas or neurofibromas. The exposure involves no more bone removal than does a posterior laminectomy, but the angle of approach reduces markedly the amount of spinal cord manipulation necessary to deal with ventrally situated lesions.

Implications of very high serum prolactin levels associated with pituitary tumors.

Five patients with pituitary tumors associated with unusually high serum prolactin levels are presented. Tumor size and the presence of suprasellar extension were variable, but the finding common to all five cases was invasion of the cavernous sinus. It is proposed that very high serum prolactin levels suggest an invasive tumor, perhaphs, specifically, invasion into a cavernous sinus. The surgical significance of this proposition is discussed.

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.