Microvascular decompression after gamma knife surgery for trigeminal neuralgia: intraoperative findings and treatment outcomes.

OBJECT: The authors sought to determine whether the results of trigeminal microvascular decompression (MVD) are influenced by prior gamma knife surgery (GKS). METHODS: Gamma knife surgery is an established procedure for treating medically intractable trigeminal neuralgia but failures do occur. The authors assessed six patients (two men and four women; mean age 52 years) who experienced pain recurrence after GKS and elected to undergo trigeminal MVD via retrosigmoid craniotomy. Three patients underwent a single GKS to a maximal dose of 80 Gy, whereas three others underwent a second GKS to total of 120 to 135 Gy. At surgery, none of the six patients demonstrated excess arachnoid thickening, grossly apparent changes in the nerve itself, or any other tissue alterations that made successful mobilization of a blood vessel from the trigeminal root entry zone technically more difficult. A single individual had a small atherosclerotic plaque in the superior cerebellar artery near its contact point with the trigeminal nerve. Follow up at a mean of 25.4 months (range 7.5-42 months) indicated that five patients were pain free. One patient had improved but still relied on medications for pain control. CONCLUSIONS: In the authors' experience, trigeminal MVD can be performed without added difficulty in patients who have previously undergone GKS. The success rates seem similar to those normally associated with MVD. Patients who elect the less invasive option of GKS can be assured that trigeminal MVD remains a viable alternative at a later date if further surgery is required.

Surgery and permanent 125I seed paraspinal brachytherapy for malignant tumors with spinal cord compression.

PURPOSE: To evaluate the functional outcome, predictors of response, and toxicity from spinal surgery and 125I brachytherapy in patients with malignant tumors resulting in spinal cord compression. METHODS AND MATERIALS: Between July 1985 and September 2001, after surgical resection, 30 patients underwent 31 intraoperative paraspinal brachytherapy procedures at Barrow Neurological Institute. Twenty-four (with 25 procedures) had follow-up at our clinic and form the basis for this report. Surgical procedures were based on the location of the impinging lesion: corpectomy or spondylectomy in 13 cases and laminectomy in 12. Permanent 125I seeds in absorbable suture were placed with open exposure after resection. RESULTS: Spinal cord compression was cervical in 4 (16%), thoracic in 14 (56%), and lumbar in 7 (28%) of the 25 cases. One patient underwent two separate procedures at different spinal sites. Of the 25 brachytherapy sites, 22 also received external beam radiotherapy (EBRT): 5, EBRT with a planned brachytherapy boost; 4, brachytherapy and prompt EBRT after recovery; and 13, brachytherapy as salvage for local failure after prior EBRT. Three had no EBRT: 1 had lymphoma treated with chemotherapy, 1 had remote previous EBRT for a childhood tumor, and 1 refused EBRT. The mean follow-up was 19.8 months. The 2- and 3-year actuarial local control rate was 87.4% and 72.9%, respectively. Four sites (16.0%) experienced local failure. The mean time to recurrence for these 4 patients was 20.3 months. Three of the four had failed prior EBRT, with surgery and brachytherapy used for salvage. The 2- and 3-year actuarial overall survival rates were 24.0% and 16.0%, mean 19.2 months. An ambulatory function score was assigned pre- and postoperatively: I, normal ambulation; II, abnormal not requiring assistance; III, abnormal requiring assistance; and IV, unable to ambulate. All patients with score I, 91% of those with score II, 67% of those with score III, and 67% of those with score IV were ambulatory after the procedure; 84% had either normal or improved ambulation postoperatively. Morbidity was restricted to four postoperative events: one cerebrospinal fluid leak, two wound infections treated in situ without removal of seeds or instrumentation, and one pulmonary embolus. No myelopathies or other neurologic sequelae were encountered. CONCLUSION: This is the largest series in the literature exploring surgery and 125I brachytherapy in the treatment of malignant spinal cord compression. We found this to be well tolerated and to result in durable local control and ambulatory function. Our results suggest a benefit to aggressive local therapy in selected patients with spinal cord compression.

Gamma knife radiosurgery for recurrent trigeminal neuralgia.

OBJECT: Pain may fail to respond or may recur after initial gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). The authors examined their experience with performing a second GKS procedure in these patients. METHODS: Twenty-nine patients underwent repeated GKS for TN at our institution between March 1997 and March 2002. Questionnaires were mailed to patients to assess the degree of their pain relief and the extent of facial numbness. Nineteen patients responded. All patients underwent repeated GKS involving a single 4-mm isocenter directed at the trigeminal nerve as it exited the brainstem (mean maximum dose 23.2 Gy). At a mean follow up of 13.5 months after the second procedure, 10 patients (53%) were pain free and medication free. Four patients (21%) were pain free but elected to continue medication in reduced dose, and two patients (11%) had incomplete but satisfactory pain control and were still taking medication. There was new-onset facial numbness in eight patients (42%), rated as tolerable in all instances. CONCLUSIONS: Patients with facial numbness had a greater likelihood of being pain free than those with no sensory loss. The authors observed no cases of corneal anesthesia, keratitis, or deafferentation pain.

Gamma knife radiosurgery for trigeminal neuralgia associated with multiple sclerosis.

OBJECT: The authors assessed the efficacy and complications from gamma knife radiosurgery (GKS) for multiple sclerosis (MS)-associated trigeminal neuralgia (TN). METHODS: There were 15 patients with MS-associated TN (MS-TN). Treatment involved three sequential protocols, 70 to 90-Gy maximum dose, using a single 4-mm isocenter targeting the ipsilateral trigeminal nerve at its junction with the pons with the 50% isodose. Pain was appraised by each patient by using Barrow Neurological Institute (BNI) Scores I through IV: I, no pain; II, occasional pain not requiring medication; IIIa, no pain but continued medication; IIIb, some pain, controlled with medication; IV, some pain, not controlled with medication; and V, severe pain/no pain relief. With a mean follow up of 17 months (range 6-38 months), 12 (80%) of 15 patients experienced pain relief. Three patients (20%) reported no relief (BNI Score V). For responders, the mean latency from treatment to the onset of pain relief was 13 days (range 1-61 days). Maximal relief was achieved after a mean latency of 56 days (range 1-157 days). Five patients underwent a second GKS after a mean interval of 534 days (range 231-946 days). The mean maximum dose at this second treatment was 48 Gy. The target was unchanged from the first treatment. All five patients who underwent repeated GKS improved. Complications were limited to delayed facial hypesthesias. Two (13%) of 15 patients experienced onset of numbness after the first GKS, as well as two of five patients following a second GKS. The patients found this mild and not bothersome. Each patient who developed hypesthesias also experienced complete pain relief. CONCLUSIONS: Gamma knife radiosurgery is an effective treatment for MS-TN. Radiosurgery carries an acceptable small risk of mild facial hypesthesias, and hypesthesia appears predictive of a favorable outcome.