Hemifacial spasm. A vascular cause.

A review of the literature as well as recent surgical observations indicate that hemifacial spasm may be caused by normal or pathological vascular structures that cross-compress the facial nerve. The critical area of compression is invariably found at the brain stem exit zone of the seventh cranial nerve. In this area the central glial investment of the facial nerve changes to peripheral or schwannian myelin. It is suspected that this anatomical junction zone may be of pathophysiologic significance when directly compressed or irritated. A retromastoid craniectomy and vascular decompression operation is highly successful in relieving hemifacial spasm while at the same time preserving facial nerve function. This is in contrast to most commonly used destructive operations for hemifacial spasm. Microsurgical techniques, however, must be employed or high morbidity and mortality may occur from the retromastoid approach.

"Failure to thrive" due to pontine glioma.

A 14-year-old boy with a five-year history of diencephalic syndrome was found to have a pontine astrocytoma. We review case reports of five similar children with diencephalic syndrome secondary to posterior fossa tumors. We also describe the clinical features, investigative procedures, and therapy of these tumors. These cases emphasize the minimal neurological findings that may be associated with brain stem gliomas and the need for consideration of these tumors in the syndromes of "failure to thrive," anorexia nervosa, and the diencephalic syndrome of infancy.

Trigeminal neuralgia. Current concepts regarding etiology and pathogenesis.

There has long been a controversy over the cause of trigeminal neuralgia. Most clinical data favor a peripheral cause. However, most of the experimental data tend to favor a central mechanism. Drugs that are effective in the treatment of trigeminal neuralgia facilitate segmental inhibition in the trigeminal nucleus, as well as depressing excitatory transmission. The most plausible hypothesis to reconcile all of these observations is that trigeminal neuralgia has a peripheral cause and a central pathogenesis. Chronic irritation of the trigeminal nerve apparently leads to both a failure of segmental inhibition in the trigeminal nucleus, and ectopic action potentials in the trigeminal nerve. This combination of increased firing and impaired efficiency of inhibitory mechanisms leads to paroxysmal discharges in the trigeminal nucleus, which are perceived as attacks of trigeminal neuralgia when they involve nociceptive trigeminothalamic-relay neurons.

Hemifacial spasm due to aneurysmal compression of the facial nerve.

Hemifacial spasm developed in a woman as the only symptom of an aneurysm of the posterior inferior cerebellar artery. Using microdissecting techniques, the aneurysm was clipped and moved from its distorting position at the brain stem exit zone of the seventh nerve. After surgery, she experienced immediate relief of her facial spasm of six years' duration. This case supports the finding that hemifacial spasm may be caused by vascular lesions of the seventh nerve at the brain stem junction. Recent surgical experience indicates that the majority of the hemifacial spasm cases may be due to normal but ectatic blood vessels that cross-compress the most proximal portion of the seventh nerve. Relief may be affected without facial paralysis by a retromastoid microvascular decompressive procedure.

Microsurgical approach to intraorbital tumors. Technique and instrumentation.

We believe that, with the modified Krönlein lateral orbitotomy microsurgical approach, most orbital tumors can be successfully removed with reduced morbidity and complications, compared with the frontotemporal craniotomy or the standard Krönlein lateral orbitotomy. The cosmetic result is quite satisfactory, and the hospital stay should be brief. The use of the operating microscope and the specifically designed and modified instruments for retraction and dissection in the orbit, combined with the efficiency of the self-irrigating bipolar coagulating forceps, add a new dimension to the safety and efficiency of orbital surgery.

Galactorrhea, amenorrhea, hyperprolactinemia, and an empty sella.

Increased serum prolactin (hPRL) and increased volume of the sella turcica as detected by roentgenography are compatible with a pituitary adenoma. The empty sella syndrome can increase sella volume, but is usually associated with minimal, if any, endocrine dysfunction. The present case details a young woman with amenorrhea, galactorrhea, elevated serum hPRL, and roentgenographic evidence of an enlarged sella turcica. Pneumoencephalography with hypocycloidal polytomography is interpreted as both an empty sella, and evidence of a pituitary adenoma. The etiology and endocrine findings in the empty sella syndrome are discussed.

The management of optic nerve sheath meningiomas.

Thirty-eight patients (39 eyes) with optic nerve sheath meningiomas were entered into a treatment plan and were followed up for at least three years. Eighteen eyes were simply observed because they had minimal functional deficit or the eye was blind. Radiation was used on six eyes with documented progressive visual loss that still had useful vision. Surgery was initially used in an attempt to remove optic nerve sheath meningiomas but was abandoned except in exceptional cases. Total surgical removal of the tumor was carried out in ten eyes with loss of vision and in which the meningioma was growing. Surgery for subtotal or complete removal of the tumor followed by radiation was carried out in five eyes exhibiting aggressive growth of the tumor. This treatment plan has helped us to treat patients with optic nerve sheath meningiomas in an orderly way.

Surgical management of orbital lymphangioma with the carbon dioxide laser.

Lymphangiomas of the ocular adnexa, especially those in the orbit, are difficult to treat because the unencapsulated tumor freely interdigitates with normal orbital tissue, obliterating any potential surgical plane. Because of the hemorrhagic and friable nature of the tumor, conventional surgical techniques are frequently complicated by bleeding. We used the CO2 laser to remove these lesions subtotally by controlled vaporization in six patients (four girls and two boys, 5 to 17 years old). Three pupils remained dilated postoperatively because of damage to the ciliary nerves and symblepharon formation occurred in one case. None of these has produced any symptoms. In one case, however, laser treatment may have produced corneal anesthesia.

Microsurgical removal of a primary intraorbital meningioma.

A 48-year-old woman with a primary intraorbital meningioma associated with the optic nerve sheath underwent a microsurgical removal of the tumor through a lateral orbitotomy. Visual recovery was essentially complete.

The relationship between survival and the extent of the resection in patients with supratentorial malignant gliomas.

Current neurosurgical opinion favors the radical surgical removal of supratentorial gliomas, when feasible, in the belief that this optimizes patient survival. Although bolstered by the results of some early investigators, the efficacy of this approach remains debatable. Therefore, we undertook a review of the English language literature of the past 30 years for a series of surgically treated malignant gliomas. Twenty reports comprising 5691 patients were identified. Only 4 found the extent of the surgical resection related to survival. In 2 of these, it followed age, histological findings, and performance status in importance. The 2 other studies did not rank the prognostic variables at all. On closer inspection, however, there does appear to be a subgroup of young patients with favorable histological findings and good performance status for whom surgery is beneficial. Future reporting of surgical results of patients with gliomas will require stratification by the known prognostic variables of age, histological findings, and performance status to characterize better this subgroup for whom surgery is beneficial.

Microdiscectomy versus chemonucleolysis.

A retrospective analysis of 50 consecutive patients treated with chemonucleolysis and 50 treated with microlumbar discectomy was carried out. Similar clinical criteria for the diagnosis of "virgin" herniated lumbar discs were used. All patients had low back or radicular pain unrelieved by a minimum of 4 weeks of conservative therapy. Physical findings included a positive straight leg raising sign, weakness of the appropriate muscle groups, and a sensory loss or evidence of depressed reflexes. All had myelograms or computed tomographic scans demonstrating an extradural defect. Compensation cases were eliminated. Results demonstrated a 90% marked improvement in the microdiscectomy category and a 58% marked improvement in the chemonucleolysis group. Four per cent of the microdiscectomy patients were unimproved, and 18% of the chemonucleolysis group required a subsequent surgical procedure. The average postoperative hospital stay was 3 days for both groups. Because of the necessity for reoperations in the chemonucleolysis group, chemonucleolysis seemed less cost-effective than microdiscectomy.

Cauda equina syndrome secondary to an improperly placed nucleotome probe.

Automated percutaneous lumbar discectomy has been shown to be a low morbidity procedure in the treatment of contained herniated lumbar discs. Described in this paper is a complication, i.e., a cauda equina syndrome secondary to a Nucleotome probe improperly placed in the thecal sac. The authors reemphasize the landmarks for the thecal sac, i.e., the medial border of the pedicles, and discuss the preventable nature of this type of complication.

Brain abscess due to Haemophilus aphrophilus: possible canine transmission.

A 58-year-old patient developed progressive right hemiparesis and a hemisensory loss. Computed tomography demonstrated a lesion in the left frontoparietal region with ring enhancement. A craniotomy was performed and an abscess was removed, which on culture grew Haemophilus aphrophilus. The same organism was isolated from the patient's poodle dog but not from three other poodles of family members. This, along with previous reports, suggests that the poodle may be a vector in the transmission of this organism, which rarely may cause a brain abscess.

Burning hands syndrome revisited.

The burning hands syndrome of spinal cord injury was first described in 1977. The syndrome is characterized by burning dysesthesias and paresthesias in the hands and may be associated with either cervical fracture/dislocation or no detectable cervical spine abnormalities. A case of burning hands syndrome without cervical spine injury is presented in which somatosensory evoked potentials and magnetic resonance imaging were used to delineate the pathophysiology of this syndrome.

Tentorial meningiomas: surgical management and results.

We report the clinical features, radiological studies, operative management, and follow-up data in a series of 27 patients with tentorial meningiomas. Headache and extremity or gait ataxia were the most common presenting symptoms. Signs of elevated intracranial pressure and cranial nerve, pyramidal, or cerebellar deficits were the most common findings on neurological examination. Computed tomography was the single most important diagnostic tool. Cerebral arteriography was considered important to define arterial and venous relationships to the tumor. Two patients in the series underwent cerebrospinal fluid shunting only. The others underwent an operation on the tumor, with or without a shunt. There were 2 postoperative deaths early in the series, 1 due to cerebellar swelling and the other due to brain stem infarction. With an average follow-up of 5.5 years, 19 patients are independent and have resumed their premorbid level of activity. The pathological anatomy of these lesions is described. The different operative approaches to this tumor are discussed.

Calvarial hemangioendothelioma with intracranial hemorrhage: case report.

A case of a hemangioendothelioma of the occipital bone that presented clinically as an acute epidural hematoma is reported. The literature regarding this rare bone tumor is reviewed. The treatment of choice seems to be wide surgical excision, but life-threatening hemorrhage may occur due to extreme tumor vascularity. The role of radiotherapy remains uncertain.

Lumbar surgery in the elderly.

By virtue of modern neuroimaging, neurosurgeons are increasingly confronted by patients once deemed too old for lumbar corrective procedures. Management of these patients is problematic, as the literature is relatively mute in regard to results and complications within this elderly cohort. We, therefore, reviewed all surgical procedures for benign lumbar disease at two large metropolitan hospitals from January 1986 to June 1988 for patients greater than or equal to 70 years of age. There were 155 procedures performed on 143 patients (male:female, 48:95); the average age of the patients was 74.9 +/- 8.8 years; there were 32 cases of herniated disc, 29 cases of disc plus hypertrophic ligament/bone, and 94 cases of lateral recess/stenosis alone. Hospital stay averaged 7.5 +/- 3.5 days, and increasing age did not correlate with an extended admission. Major morbidity was low (6.9%), and there were no deaths. At follow-up, an average of 34.3 +/- 12.2 months postoperatively, 66.6% (56 of 84) of the patients reported no or minimal discomfort, whereas 15.4% (13 of 84) had not improved at all. Overall, 77.3% (65/84) were pleased with their procedure. These data represent the most comprehensive review in the literature of lumbar procedures in the elderly and indicate that these operations may be undertaken in this population with acceptable morbidity and a reasonable expectation of clinical improvement.

Clinical considerations concerning detection of venous air embolism.

Venous air embolism during neurosurgical procedures (detected by Doppler Ultrasound and aspiration via a right atrial catheter) was noted in 100 of 400 patients in the sitting position, 5 of 60 patients in the lateral position, 7 of 48 patients in the supine position, and 1 of 10 individuals monitored in the prone position. We confirmed venous air embolism in many of these cases by using serial technetium-macroaggregated albumin lung scans. Gravitational gradients from the venous portal of entrance to the right side of the heart were as small as 5.0 cm, with aspiration of 200 ml of air occurring. Doppler ultrasonic air bubble detection and aspiration through a previously inserted right atrial catheter are critical factors in the diagnosis and treatment of this condition.

Magnetic resonance imaging and intraoperative neurosonography in syringomyelia.

Treatment of syringomyelia remains a difficult and controversial problem. However, the recent advent of magnetic resonance imaging (MRI) and intraoperative ultrasound allows a more precise approach to the diagnosis and management of this disorder. Experience with 27 cases of syringomyelia has shown that MRI is superior to all other forms of diagnostic imaging for the exact anatomical delineation of syrinxes and other spinal cavities. One-third of the syrinxes demonstrated by MRI were either not adequately visualized or missed by myelography and/or computed tomographic scanning. Intraoperative ultrasound has been used to allow more precise operative approaches to the syrinx as well as to guide the exact placement of shunt tubes into syrinx cavities. A method has also been developed to allow intraoperative ultrasound of the spinal cord with patients in the sitting position.

Intrasellar mucocele simulating pituitary adenoma: case report.

Mucoceles occupying the sella turcica with suprasellar extension are quite rare. A case of intrasellar mucocele is reported. The preoperative clinical and computed tomographic appearance could not be differentiated from that of pituitary adenoma.