Gamma knife surgery for trigeminal neuralgia

OBJECT: Stereotactic radiosurgery is an increasingly used and the least invasive surgical option for patients with trigeminal neuralgia. In this study, the authors investigate the clinical outcomes in patients treated with this procedure. METHODS: Independently acquired data from 220 patients with idiopathic trigeminal neuralgia who underwent gamma knife radiosurgery were reviewed. The median age was 70 years (range 26-92 years). Most patients had typical features of trigeminal neuralgia, although 16 (7.3%) described additional atypical features. One hundred thirty-five patients (61.4%) had previously undergone surgery and 80 (36.4%) had some degree of sensory disturbance related to the earlier surgery. Patients were followed for a maximum of 6.5 years (median 2 years). Complete or partial relief was achieved in 85.6% of patients at 1 year. Complete pain relief was achieved in 64.9% of patients at 6 months, 70.3% at 1 year, and 75.4% at 33 months. Patients with an atypical pain component had a lower rate of pain relief (p = 0.025). Because of recurrences, only 55.8% of patients had complete or partial pain relief at 5 years. The absence of preoperative sensory disturbance (p = 0.02) or previous surgery (p = 0.01) correlated with an increased proportion of patients who experienced complete or partial pain relief over time. Thirty patients (13.6%) reported pain recurrence 2 to 58 months after initial relief (median 15.4 months). Only 17 patients (10.2% at 2 years) developed new or increased subjective facial paresthesia or numbness, including one who developed deaf-ferentation pain. CONCLUSIONS. Radiosurgery for idiopathic trigeminal neuralgia was safe and effective, and it provided benefit to a patient population with a high frequency of prior surgical intervention.     

Gamma knife surgery with a dose of 75 to 76.8 Gray for trigeminal neuralgia

OBJECT: The author presents a large series of patients with idiopathic trigeminal neuralgia (TN) who were treated with gamma knife surgery (GKS), at a maximum dose of 75 to 76.8 Gy, and followed up in a nearly uniform manner for up to 4.6 years. METHODS: Two hundred ninety-three patients were treated and followed up for at least 6 months (range 0.4-4.6 years, median 1.9 years). At the final follow-up review, there was complete (100%) pain relief without medicines in 64 patients (21.8%), 90% or greater relief with or without small doses of medicines in 86 (29.4%), between 75 and 89% relief in 31 (10.6%), between 50 and 74% relief in 19 (6.5%), and less than 50% relief in 23 patients (7.8%). Recurrent pain requiring a second procedure occurred in 70 patients (23.9%). Kaplan-Meier analysis showed that 100%, 90% or greater, and 50% or greater pain relief was obtained and maintained for 3.5 to 4.1 years in 5.6, 23.7, and 50.4% patients, respectively. Of 31 patients who described pain relief ranging from 75 to 89%, 80% of patients described it as good and 10% as excellent; of 17 patients who reported between 50 and 74% pain relief, 53% described it as good and none as excellent (p = 0.014). Dysesthesia scores greater than 5 (scale of 0-10, in which a score of 10 represents excruciating pain) occurred in four (3.2%) of 126 patients who had not undergone prior surgery; all these patients obtained either good or excellent relief from TN pain. There were 36 patients in whom the TN had atypical features; these patients were less likely to attain at least 50% or at least 90% pain relief compared with those without atypical TN features (p = 0.001). CONCLUSIONS: Gamma knife surgery is a safe and effective way to relieve TN. Patients who attain between 75 and 89% pain relief are much more likely to describe this outcome as good or excellent than those who attain between 50 and 74% pain relief.     

原发性三叉神经痛的伽玛刀治疗

目的 评价伽玛刀治疗原发性三叉神经痛的疗效。方法 72例原发性三叉神经痛采用伽玛刀治疗,靶点为三叉神经根近脑干段,4mm准直器,中心剂量(70—80)Gy。结果 随访2年以上5l例,治愈39例(76．5％),有效7例(13．7％),无效5例(9．8％)。19例(37．3％)出现一过性轻度面部麻木,感觉减退,无其它并发症。结论 伽玛刀治疗原发性三叉神经痛疗效确切,无严重并发症。     

Gamma knife radiosurgery for trigeminal neuralgia: the Washington University initial experience

Seventy-three patients were evaluated for the changes in pain relief, numbness and paresthesias after Gamma Knife radiosurgery to a maximum dose of 76-87 Gy for trigeminal neuralgia. Patients experienced pain relief as follows: 59% attained complete pain relief without prior surgery (33% with prior surgery); 25% achieved > or = 50% pain reduction (28% with prior surgery); 11% of surgery patients obtained minor pain relief, and 16% of patients without surgery had no relief (28% with prior surgery). Level of pain decreased rapidly within 6 weeks after radiosurgery. Numbness/paresthesias developed slowly over the first 12-15 months. Bothersome levels were experienced by 15% of the patients without prior surgery (22% with prior surgery). Comparison of the occurrence of numbness/paresthesias, with respect to prior surgery, was not statistically significant. Only 2% of all patients had persistently bothersome side effects. In conclusion, radiosurgery is an effective treatment of trigeminal neuralgia, especially for those patients not having prior surgery.     

Gamma knife radiosurgery for trigeminal neuralgia: experience at the Barrow Neurological Institute

Forty-three patients with trigeminal neuralgia (TN) unresponsive to pharmacologic treatment and/or prior invasive procedures underwent stereotactic radiosurgery with the Gamma Knife (GK). Outcome was evaluated by a standardized questionnaire mailed to each patient. The mean follow-up was 9 months. Fifteen patients (35%) reported no trigeminal pain and were no longer taking medication. Three patients (7%) experienced occasional pain, but were no longer taking medication. In 15 patients (35%), pain improved and was adequately controlled by medication, often in lower dosages than preoperatively. Pain was reduced in 9 patients (21%), but their symptoms were still inadequately controlled by drug therapy, and 1 patient (2%) reported no pain relief after treatment. Three patients (7%) described new facial numbness, but in none was this bothersome. GK radiosurgery for TN appears to have minimal morbidity, although the success rate may be slightly lower than that of other operative procedures. More patients and longer follow-up are needed before drawing final conclusions regarding efficacy and complications.     

Gamma knife radiosurgery for treatment of trigeminal neuralgia in multiple sclerosis patients

BACKGROUND: Trigeminal neuralgia is a paroxysmal pain syndrome commonly associated with multiple sclerosis. While gamma knife radiosurgery has been shown to be an effective treatment for most cases of trigeminal neuralgia, it is considered to be less efficacious in patients with multiple sclerosis and less viable as a treatment option. METHODS: Seven patients with multiple-sclerosis-associated trigeminal neuralgia were identified from 50 consecutive patients treated for trigeminal neuralgia at the Memorial-Hermann Gamma Knife Radiosurgery Center. A Leksell gamma knife was used to deliver 80 or 90 Gy to a single 4-mm isocenter targeting the fifth nerve root entry zone into the pons. The patients were followed for a median period of 28 months and graded on a scale of 1 to 5, adopted from the Barrow Neurological Institute. RESULTS: All 7 patients showed excellent responses to radiosurgery with complete resolution of their pain and cessation of pain medications. The time to maximal response varied from 1 day to 8 months after treatment. The only complication was persistent facial numbness over the distribution of V2 and V3 which occurred in 4 patients. One patient experienced a recurrence of pain (grade 3) 24 months after radiation treatment, and she is currently being treated with carbamazepine. CONCLUSIONS: Gamma knife radiosurgery is an effective treatment option for trigeminal neuralgia patients with multiple sclerosis. These patients should be informed that there appears to be a higher incidence of facial numbness and that a longer period of several months should be allowed before the full effects of treatment may be observed as compared to the general population.     

Gamma knife surgery for idiopathic trigeminal neuralgia performed using a far-anterior cisternal target and a high dose of radiation

OBJECT: Gamma knife surgery (GKS) has emerged as a suitable treatment of pharmacologically resistant idiopathic trigeminal neuralgia. The optimal radiation dose and target for this therapy, however, remain to be defined. The authors analyzed the results of GKS in which a high dose of radiation and a distal target was used, to determine the best parameters for this treatment. METHODS: The authors evaluated results in 47 patients who were treated with this approach. All patients underwent clinical and magnetic resonance imaging examinations at 6 weeks, 6 months, and 1 year post-GKS. Fifteen potential prognostic factors associated with favorable pain control were studied. The mean follow-up period was 16 months (range 6-42 months). The initial pain relief was excellent (100% pain control) in 32 patients, good (90-99% pain control) in seven patients, fair (50-89% pain control) in three patients, and poor (< 50% pain control) in five patients. The actuarial curve of pain relief displayed a 59% rate of excellent pain control and a 71% excellent or good pain control at 42 months after radiosurgery. Radiosurgery-induced facial numbness was bothersome for two patients and mild for 18 patients. Three prognostic factors were found to be statistically significant factors for successful pain relief: a shorter distance between the target and the brainstem, a higher radiation dose delivered to the brainstem, and the development of a facial sensory disturbance after radiosurgery. CONCLUSIONS: To optimize pain control and minimize complications of this therapy, we recommend that the nerve be targeted at a distance of 5 to 8 mm from the brainstem.     

Gamma knife radiosurgery for trigeminal schwannomas

BACKGROUND: Trigeminal schwannomas are uncommon tumors that may be microsurgically removed in selected cases, albeit with significant risk for new neurological morbidity. We evaluated the role of stereotactic radiosurgery as an alternative for patients with newly diagnosed or residual trigeminal schwannomas. METHODS: The records of 23 patients who underwent radiosurgery for trigeminal schwannoma were reviewed. The most frequent presenting symptoms were facial numbness (11 patients), diplopia (6 patients), and facial pain (3 patients). One patient presented with partial complex seizures as the first symptom. Twelve patients had undergone one or more prior resections. Eleven underwent radiosurgery on the basis of imaging diagnosis only. The mean tumor volume was 4.5 mL (range 0.46-11.2 cc). Radiosurgery was performed using a median marginal dose of 15 Gy (range, 13-20 Gy). RESULTS: At a median imaging follow-up of 40 months (range, 12-146), 20 of 22 evaluable patients (91%) had tumor growth control (regression in 15 and no further tumor growth in 5). One 80-year-old patient died of unrelated cause 4 months after radiosurgery. Two patients with enlarged tumors were treated effectively with repeat radiosurgery. Twelve of 23 patients (52%) reported improvement and 9 (39%) had no change in their symptoms. Two patients noted new neurological complaints (transient facial weakness in 1 patient and worsening of the preradiosurgery facial numbness in another patient). CONCLUSIONS: Radiosurgery is an effective minimally invasive management option for patients with residual or newly diagnosed trigeminal schwannomas.     

Prospective controlled trial of gamma knife surgery for essential trigeminal neuralgia

OBJECT: Stereotactic radiosurgery is an alternative to conventional surgery for the treatment of trigeminal neuralgia. The authors conducted a prospective evaluation of the safety and efficacy of this method in a large series of patients. METHODS: A total of 100 patients presenting with trigeminal neuralgia were treated and followed up for a minimum of 12 months. The mean age was 68.2 years; 54 patients were male, and 46 were female. Seven had a history of multiple sclerosis, and 42 had already received conventional surgical treatment for trigeminal neuralgia. The intervention consisted of gamma knife surgery to the retrogasserian cisternal portion of the fifth cranial nerve. The median dose used at the maximum was 85 Gy (range 70-90 Gy). The number and intensity of pain attacks were recorded by the patient from 3 months before radiosurgery to a minimum of 12 months after treatment. Before and a minimum of 12 months after treatment, the patient completed a quality-of-life questionnaire. Neurological examination and quantitative sensory testing to evaluate sensory perception were performed by an independent neurologist over this same time period. At the last visit 83 of 100 patients were reported to be pain free. Fifty-eight of these 83 patients had stopped taking medication during the study. All quality-of-life parameters were improved (p < 0.001). Six patients reported facial paresthesia, and four patients reported hypesthesia. These symptoms were classified as mild. None of the complications reported for other techniques were observed. CONCLUSIONS: Radiosurgery is a safe and effective alternative treatment for trigeminal neuralgia and is associated with a particularly low rate of hypesthesia.     

Long-term outcome after gamma knife surgery for secondary trigeminal neuralgia.

OBJECT: This study was directed to evaluate the potential role of gamma knife surgery (GKS) in the treatment of secondary trigeminal neuralgia (TN). The authors have identified three anatomicoclinical types of secondary TN requiring different radiosurgical approaches. METHODS: Pain control was retrospectively analyzed in a population of patients harboring tumors of the middle or posterior fossa that involved the trigeminal nerve pathway. This series included 53 patients (39 women and 14 men) treated using GKS between July 1992 and June 1997. The median follow-up period was 55 months. Treatment strategies differed according to lesion type, topography, and size, as well as visibility of the fifth cranial nerve in the prepontine cistern. Three different treatment groups were established. When the primary goal was treatment of the lesion (Group IV, 46 patients) we obtained pain cessation in 79.5% of cases. In some patients in whom GKS was not indicated for treatment of the lesion, TN was treated by targeting the fifth nerve directly in the prepontine cistern if visible (Group II, three patients) or in the part of the lesion including this nerve if the nerve root could not be identified (Group III, four patients). No deaths and no radiosurgically induced adverse effects were observed, but in two cases there was slight hypesthesia (Group IV). The neuropathic component of the facial pain appeared to be poorly sensitive to radiosurgery. At the last follow-up examination, six patients (13.3%) exhibited recurrent pain, which was complete in four cases (8.8%) and partial in two (4.4%). CONCLUSIONS: The results of GKS regarding facial pain control are very similar to those achieved by microsurgery according to series published in the literature. Nevertheless, the low rate of morbidity and the greater comfort afforded the patient render GKS safer and thus more attractive.