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OBJECTIVE: To identify systematically all the studies reporting outcomes and complications of stereotactic radiosurgery for trigeminal neuralgia and to evaluate them against predefined quality criteria. and minimum dose of 70 Gy. RESULTS: Of 38 studies identified, four could be used to evaluate rates of pain relief on a yearly basis, and two for actuarial rates of complete pain relief; seven provided data on latencies and 18 were used to evaluate complications.

 Stereotactic radiosurgery for primary trigeminal neuralgia: state of the evidence and recommendations for future reports.

Lopez BC, Hamlyn PJ, Zakrzewska JM.   J Neurol Neurosurg Psychiatry. 2004 Jul;75(7):1019-24. Department of Neurosurgery, The Royal London Hospital, London, UK. benjami

Pain relief typically occurs within three months. Complete relief is initially achieved by three quarters of the patients, but half maintain this outcome at three years. One half or less can permanently stop drug treatments. Sensory disturbance, including anaesthesia dolorosa, is the most frequent complication of stereotactic radiosurgery.

CONCLUSIONS: Outcomes after stereotactic radiosurgery appear in line with other ablative techniques. Results are better when it is used as primary treatment in patients with typical symptoms. Current data are largely observational and the quality is generally poor. This technique should be evaluated in a randomised, controlled trial with universal outcome measures, actuarial methodology, and validated measures of patient satisfaction and quality of life
 
Gamma knife surgery with a dose of 75 to 76.8 Gray for trigeminal neuralgia.

Brisman R.      J Neurosurg. 2004 May;100(5):848-54.

Department of Neurological Surgery, College of Physicians and Surgeons, Columbia University, New York Presbyterian Hospital, New York, New York,

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.

Repeat gamma knife radiosurgery for trigeminal neuralgia.

Brisman R.   Stereotact Funct Neurosurg. 2003;81(1-4):43-9.

Department of Neurological Surgery, College of Physicians and Surgeons, Columbia University, New York Presbyterian Hospital, Columbia Presbyterian Medical Center, New York, NY, USA. rb36@columbia.edu

BACKGROUND: Although gamma knife radiosurgery (GKRS) has been shown to be safe and effective for the treatment of trigeminal neuralgia (TN), there are few studies that report the results of a second GKRS. METHOD: Between May 22, 1998 and April 1, 2003, we treated 335 primary TN patients with GKRS. All received a maximum dose of 75 Gy to the cisternal trigeminal nerve. 45 patients with recurrent or persistent TN were treated with a maximum dose of 40 Gy at a second GKRS and were available for at least 6 months of follow-up. RESULTS: Final pain relief (mean of 15 months after second GKRS) was 50% or greater in 28 of the 45 patients (62.2%). Patients who had no neurosurgical procedure prior to their first GKRS were more likely to have pain relief of 50% or greater following the second GKRS (p = 0.042). Significant new dysesthesias (score greater than 5 on a scale of 0-10) developed in 2 patients (4.4%). CONCLUSION: Repeat GKRS has a good chance of relieving TN pain without complications and is more likely to relieve pain in those who did not have any procedure prior to their first GKRS

Repeat gamma knife radiosurgery for refractory or recurrent trigeminal neuralgia: treatment outcomes and quality-of-life assessment.

Herman JM, Petit JH, Amin P, Kwok Y, Dutta PR, Chin LS.   Int J Radiat Oncol Biol Phys. 2004 May 1;59(1):112-6.

Department of Radiation Oncology, University of Maryland Medical Center, Baltimore, MD 21201, USA.

PURPOSE: Stereotactic radiosurgery (SRS) has become a minimally invasive treatment modality for patients with refractory trigeminal neuralgia. It is unclear, however, how best to treat patients with pain that is refractory or recurrent after initial SRS. We report on treatment outcomes and quality of life for patients treated with repeated SRS for refractory or recurrent trigeminal neuralgia. METHODS AND MATERIALS: Between June 1996 and June 2001, 112 patients with trigeminal neuralgia were treated with SRS at the University of Maryland Medical Center. Eighteen patients underwent repeat SRS 3-42 months (median, 8 months) after initial radiosurgery because of unsatisfactory or unsustained pain relief. Patients received a median prescription dose of 75 and 70 Gy, respectively, for the first and second treatments. Self-reports of pain control were assessed with a standard questionnaire containing the complete Barrow Neurologic Institute Pain Scale. RESULTS: The median follow-up was 37.5 months (range, 12-68 months) after initial SRS and 24.5 months (range, 6-65 months) after repeat SRS. For the 18 patients in this series, the percentage of patients reporting excellent, good, fair, and poor responses after the initial and repeat SRS was 50%, 28%, 6%, and 16% and 45%, 33%, 0%, and 22%, respectively. None of the 3 patients with pain refractory to initial SRS responded to repeat SRS. Among those with recurrent pain after initial SRS, 14 patients (93%) achieved excellent or good pain outcomes after repeat SRS. The actuarial analysis revealed a 1-year recurrence rate of 22%, with no patients reporting recurrent pain after 9 months of follow-up. Two patients (11%) reported new or increased facial numbness after retreatment, which was described as bothersome by one. Repeat SRS resulted in a median 60% improvement in quality of life, and 56% of patients believed that the procedure was successful. CONCLUSION: Despite a modest dose reduction, repeat SRS provided similar rates of complete pain control as the initial procedure, but was not effective for patients with no response to initial treatment. Repeat SRS was more efficacious for those patients who experienced longer periods of pain relief after the initial SRS. The incidence of complications was not significantly different from that observed for initial SRS. In this series, most patients had significant improvements in quality of life.

Gamma knife radiosurgery for trigeminal neuralgia: comparing the use of a 4-mm versus concentric 4- and 8-mm collimators.

Kanner AA, Neyman G, Suh JH, Weinhous MS, Lee SY, Barnett GH.    Stereotact Funct Neurosurg. 2004;82(1):49-57.

Department of Neurosurgery, The Cleveland Clinic Health System Gamma Knife Center, Cleveland, Ohio, USA.

PURPOSE: Gamma knife (GK) radiosurgery for trigeminal neuralgia (TN) has been effective in 50-80% of cases when using a single 4-mm collimator and a maximum dose of 60-90 Gy. Attempting to improve the response rate by increasing the dose may lead to increased risk of facial numbness or disturbed sensation. Combined use of 4- and 8-mm collimators results in a larger target volume, which would potentially treat a larger region of the nerve without increasing the maximum dose. MATERIALS AND METHODS: One hundred-one patients suffering from medically refractory TN were evaluated. Fifty-four were treated with a single shot using a 4-mm helmet and 47 with concentrically aimed, equally weighted 4- and 8-mm helmets. 75 Gy were prescribed to the 100% isodose line (using a 4-mm helmet output factor of 0.80) in all cases. The outcome was assessed by interview or outpatient visit. RESULTS: An excellent/good response was seen in 57.8 vs. 71.4%, respectively, with a partial response of 13.3 vs. 2.3%, respectively (p > 0.05). Pain recurrence occurred in 28.6 vs. 23.2%, respectively (p > 0.05). CONCLUSION: The use of a combined concentric 4- and 8-mm collimator treatment for medically refractory TN at a maximum dose of 75 Gy does not improve outcome as compared with a single 4-mm collimator with an equivalent maximum dose

 

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

Massager N, Lorenzoni J, Devriendt D, Desmedt F, Brotchi J, Levivier M.  J Neurosurg. 2004 Apr;100(4):597-605.

Gamma Knife Center, Department of Neurosurgery, Erasme Hospital, Brussels, Belgium. nmassage@ulb.ac.be

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 neuralgia: a study of predictors of success, efficacy, safety, and outcome at LSUHSC.

Shaya M, Jawahar A, Caldito G, Sin A, Willis BK, Nanda A.  Surg Neurol. 2004 Jun;61(6):529-34

Department of Neurosurgery, Louisiana State University Health Sciences Center in Shreveport, 71130, USA.

BACKGROUND: Trigeminal neuralgia (TN) is a painful condition of controversial origin; however, vascular compression of the root entry zone of the trigeminal nerve is thought to be responsible in some cases. Recently, stereotactic radiosurgery has been established as an alternative treatment for medically intractable TN. METHODS: Forty patients with medically refractory TN underwent gamma knife surgery for pain control at our institution. Dose planning was based on high-resolution, contrast-enhanced, axial, volume acquisition magnetic resonance images. Images were reviewed to detect vascular compression of the trigeminal nerve at the root entry zone by an observer blinded to the affected side and the outcome. Another observer, blinded to radiologic findings, conducted the patient follow-up. Results were classified as excellent and good (favorable outcomes) and failure (unfavorable) based upon the intensity of pain, frequency of episodes, pain medications, and need for additional interventions after radiosurgery. RESULTS: Pain was left-sided in 22 patients and right-sided in 18 patients. Vascular compression of the affected nerve at the root entry zone was demonstrable in 14 patients. Prescription dose ranged from 70 to 90 Gy. At a median follow-up of 14 months (range, 3-31 months), 16 patients (40%) had excellent pain control, 12 (30%) had good control, while 12 (30%) had failed treatment. The Kaplan-Meier actuarial pain control rate at 15 months was 82.25 +/- 0.8% (95%CI). Magnetic resonance detectable vascular compression did not affect the outcome (p = 0.6). Increasing marginal dose (> or =40Gy) was a significant predictor of favorable outcome (p = 0.015). CONCLUSIONS: gamma knife surgery is an effective and safe treatment for TN. In our study, we found that vascular compression of the nerve at the root entry zone was not a predictor