Peter J. Jannetta

The long-term outcome of microvascular decompression for trigeminal neuralgia

BACKGROUND Several surgical procedures to treat trigeminal neuralgia (tic douloureux) are available, but most reports provide only short-term follow-up information. METHODS We describe the long-term results of surgery in 1185 patients who underwent microvascular decompression of the trigeminal nerve for medically intractable trigeminal neuralgia. The outcome of the procedure was assessed prospectively with annual questionnaires. RESULTS Of the 1185 patients who underwent microvascular decompression during the 20-year study period, 1155 were followed for 1 year or more after the operation. The median follow-up period was 6.2 years. Most postoperative recurrences of tic took place in the first two years after surgery. Thirty percent of the patients had recurrences of tic during the study period, and 11 percent underwent second operations for the recurrences. Ten years after surgery, 70 percent of the patients (as determined by Kaplan-Meier analysis) had excellent final results-that is, they were free of pain without medication for tic. An additional 4 percent had occasional pain that did not require long-term medication. Ten years after the procedure, the annual rate of the recurrence of tic was less than 1 percent. Female sex, symptoms lasting more than eight years, venous compression of the trigeminal-root entry zone, and the lack of immediate postoperative cessation of tic were significant predictors of eventual recurrence. Having undergone a previous ablative procedure did not lessen a patients likelihood of having a cessation of tic after microvascular decompression, but the rates of burning and aching facial pain, as reported on the last follow-up questionnaire, were higher if a trigeminal-ganglion lesion had been created with radiofrequency current before microvascular decompression. Major complications included two deaths shortly after the operation (0.2 percent) and one brain-stem infarction (0.1 percent). Sixteen patients (1 percent) had ipsilateral hearing loss. CONCLUSIONS Microvascular decompression is a safe and effective treatment for trigeminal neuralgia, with a high rate of long-term success.

Transplantation of cultured human neuronal cells for patients with stroke

Article abstract Transplantation of cultured neuronal cells is safe in animal models and improves motor and cognitive deficits in rats with stroke. The authors studied the safety and feasibility of human neuronal cellular transplantation in patients with basal ganglia stroke and fixed motor deficits, including 12 patients (aged 44 to 75 years) with an infarct 6 months to 6 years previously (stable for at least 2 months). Serial evaluations (12 to 18 months) showed no adverse cell-related serologic or imaging-defined effects. The total European Stroke Scale score improved in six patients (3 to 10 points), with a mean improvement 2.9 points in all patients (p = 0.046). Six of 11 PET scans at 6 months showed improved fluorodeoxyglucose uptake at the implant site. Neuronal transplantation is feasible in patients with motor infarction.

Neurogenic hypertension: etiology and surgical treatment. I. Observations in 53 patients.

Although an extensive literature exists concerning essential arterial hypertension, the primary etiology has been unclear. Arterial compression of the left lateral medulla oblongata by looping arteries of the base of the brain was seen incidently in 51 of 53 hypertensive patients who underwent left retromastoid craniectomy and microvascular decompression for unrelated cranial nerve dysfunctions. Such compression was not noted in normotensive patients. Treatment by vascular decompression of the medulla was performed in 42 of the 53 patients. Relief in the hypertension was seen in 32 of the patients and improvement in four. Arteriosclerosis and arterial ectasia contribute to arterial elongation and looping. If pulsatile compression of the left lateral medulla occurs, hypertension may develop as a consequence of an imbalance in the neural control systems that normally regulate blood pressure. The hypertension may further contribute to arterial elongation, providing a vicious circle of pathophysiologic changes.

Intracranially recorded responses from the human auditory nerve: New insights into the origin of brain stem evoked potentials (BSEPs)

Auditory evoked potentials were recorded intracranially from the 8th nerve during neurosurgical procedures. The potentials had a large negative peak that occurred 3.0--3.7 msec after the onset of the stimulus (2 000 Hz tone bursts). When these potentials were compared with the scalp recorded brain stem evoked potentials (BSEPs) the intracranial response was found to match the latencies of the P2N3 complex of the BSEP. The results are interpreted as showing that the neural generator of the second peak of the BSEP is the intracranial portion of the auditory nerve and not, as was earlier assumed, the cochlear nucleus.

Disabling positional vertigo

We have identified a group of patients with vestibular disorders whose symptoms are not consistent with the commonly recognized syndromes such as Menieres disease, benign paroxysmal positional vertigo, and vestibular neuronitis. These patients have a constant positional vertigo and are often nauseated to an extent that makes them disabled. Their symptoms do not respond to conventional medical treatment or habituating therapy. We have found specific clinical-pathological signs in these patients that indicate that the vestibular nerve is compressed intracranially by blood vessels. Treatment of nine such patients by microvascular decompression of the eighth nerve brought total relief of symptoms in eight patients and improvement in one. We suggest that this syndrome be named disabling positional vertigo.

Prevention of Reactivated Herpes Simplex Infection by Human Leukocyte Interferon after Operation on the Trigeminal Root

Microneurosurgical procedures on the trigeminal-nerve root are often followed by reactivation of herpes simplex virus infection, manifested by herpes labialis or oropharyngeal herpesvirus shedding or both. In a double-blind study of the ability of human leukocyte interferon to prevent this reactivation, patients with a history of herpes labialis were given 7 x 10(4) U of interferon per kilogram of body weight per day or placebo for five days beginning on the day before operation. In 18 patients treated with placebo, herpes labialis developed in 10, and virus shedding in the oropharynx in 15. In 19 patients treated with interferon, lesions developed in five, and shedding in eight. The frequency of reactivation as measured by lesions or positive throat cultures or both was significantly reduced by interferon (P less than 0.05). Of 127 daily throat-wash cultures in the placebo group, 42 per cent were positive for herpesvirus, but of 134 in the interferon group, only 9 per cent were positive (P less than 0.001). We conclude that interferon at a well-tolerated dosage reduces reactivation of latent herpes simplex virus infection after a potent operative stimulus.

Meningiomas involving the clivus: a six-year experience with 41 patients

A series of 41 meningiomas involving the clivus operated on from July 1983 to January 1990 is reported. The presenting symptoms and signs of these patients were similar to those reported previously. All the patients were evaluated by pre- and postoperative thin-section, high-resolution computed tomography using soft tissue and bone algorithms. Most of the patients also underwent magnetic resonance imaging. The regions of the clivus involved by tumor were divided into upper, middle, or lower regions on the basis of anatomical landmarks. The diameter of the tumor was measured in three axes, and a tumor volume and a tumor equivalent diameter were computed to categorize tumors as small, medium, large, or giant types. There were 9 medium, 27 large, and 5 giant tumors in this series. Some simple and some complex operative approaches were employed to effect tumor removal. Large and giant tumors often required more than one operative approach to remove the tumor. Intraoperative technical difficulties included tumor consistency, vascularity, dissection from the brain stem, and vascular and cranial nerve encasement. Postoperative computed tomographic scans documented total excision in 32 patients (78%). Residual tumor remained in the clival or cavernous sinus areas. These patients were either being observed, or were treated with gamma knife radiosurgery. There was one operative death due to pneumonia (2%), and three patients (7%) suffered permanent major neurological changes, presumably due to vascular occlusions in the posterior circulation. In the follow-up period, which ranged from 3 to 76 months, 2 patients (6%) with tumors that had appeared to be totally excised experienced recurrence. These patients were treated by a second operation, alone or in combination with radiation therapy. Two patients who had subtotal excisions (25%) had evidence of regrowth. In 2 patients, tumor growth continued despite gamma knife radiosurgery or external beam radiotherapy.

Evoked potentials from the inferior colliculus in man

Sound-evoked potentials were recorded from the inferior colliculus in man when it was exposed during surgery. The earliest response to controlateral stimulation with 2000 Hz tone bursts at 90 dB was a positive deflection with a latency of about 6.5 msec that was followed by a slow, negative deflection that lasted about 5 msec. It is supposed that this surface-positive peak originates in the lateral lemniscus. Its latency matched that of the fifth vertex-positive wave (V) of the BSEP recorded from the scalp. Superimposed on the slow potential were several peaks. These peaks emerged clearly after the slow components were removed by filtering. The peaks then were shown to have latencies that matched the latencies of peaks VI, VII and VIII of the scalp-recorded BSEP.

Microvascular Decompression for Glossopharyngeal Neuralgia

Glossopharyngeal neuralgia is an uncommon cause of facial pain with a relative frequency of 0.2 to 1.3% when compared with trigeminal neuralgia. It is characterized by intermittent, lancinating pain involving the posterior tongue and pharynx, often with radiation to deep ear structures. Since its first description in 1910 by Weisenburg, a variety of destructive procedures have been performed to provide relief in patients whose pain was refractory to medical treatment. These procedures all necessitated the sacrifice of the glossopharyngeal nerve and, in most cases, also involved the destruction of at least part of the vagus nerve as well. In 1977, Laha and Jannetta reported good results in four patients who underwent microvascular decompression of the glossopharyngeal and vagus nerves for glossopharyngeal neuralgia. Since 1971, 40 patients have undergone microvascular decompression of the glossopharyngeal and vagus nerves for treatment of typical glossopharyngeal neuralgia. This procedure provided excellent immediate results (complete or > 95% relief of pain) in 79%, with an additional 10% having a substantial (> 50%) reduction in pain. Long-term follow-up (mean, 48 mo; range, 6-170 mo) reveals excellent results (complete or > 95% reduction in pain without any medication) in 76% of the patients and substantial improvement in an additional 16%. There were two deaths at surgery (5%) both occurring early in the series as the result of hemodynamic lability causing intracranial hemorrhage. Three patients (8%) suffered permanent 9th nerve palsy. (ABSTRACT TRUNCATED AT 250 WORDS)

Microvascular decompression in hemifacial spasm: Intraoperative electrophysiological observations

Facial muscle responses in patients with hemifacial spasm undergoing microvascular decompression operations were recorded. Two peripheral branches of the facial nerve were stimulated and the electrical responses of muscles innervated by these branches were studied to see how the lateral spread of activity that is known to be present in these patients was affected by decompressing the facial nerve. In some of the patients the hemifacial spasm ceased when the dura mater was opened, in some it ceased when the arachnoid was opened, and in others the spasm persisted until the offending vessel was dissected away from the nerve. The lateral spread of activity elicited by antidromic stimulation of a branch of the facial nerve was less affected by opening of the dura mater or arachnoid: it usually persisted until the blood vessel that had been compressing the facial nerve was removed and reappeared when the vessel that had been compressing the facial nerve was allowed to slip back onto the nerve. This seems to indicate that microvascular decompression of the facial nerve is effective in alleviating hemifacial spasm because it removes the actual cause of the disorder rather than simply causing local injury to the nerve as a result of the procedure.