Gamma Knife radiosurgery for treatment of trigeminal neuralgia

Abstract

Sixty patients with trigeminal neuralgia who did not have a response to pharmacologic treatment (including 22 who had no response to conventional surgical treatment) underwent stereotactic radiosurgical treatment with the Leksell Gamma Knife. A radiosurgical maximum dose of 70 Gy was delivered to the trigeminal nerve root adjacent to the pons via a 4-mm collimator helmet in 51 patients who presented with trigeminal neuralgia unrelated to tumors. In these patients, the root was localized by stereotactic MRI. Follow-up assessment of pain relief was accomplished by a third party not involved in the patients' clinical care. Within a latency period of 1 day to 4 months following the treatment, 38 of 51 patients (74.5%) were completely free of pain and eventually all medications were tapered off. An additional seven patients (13.7%) experienced reductions in pain from 50 to 90% and utilized little or no medications. Patients who had no prior surgical intervention fared much better than those who had previous surgery to relieve their facial pains. At last follow-up, a mean of 16.3 months (range 6-36 months) after treatment, 41 patients (80.4%) remained pain-free or had marked pain reduction. There were four patients with recurrent pain. All 26 patients with classical symptoms of trigeminal neuralgia with no atypical features who had no prior surgery, had complete or nearly complete pain relief, and none of these patients had recurrent pain. Nine patients with trigeminal neuralgia due to tumors received standard radiosurgical treatment directed at their tumors, and eight of nine (88.8%) had pain relief. Of the total of 60 patients treated for trigeminal neuralgia, 49 (81.7%) experienced complete or nearly complete relief of pain at last follow-up. Only one patient with pre-existing facial sensory loss due to a tumor had a mild increase in facial numbness. No other patient experienced either loss of facial sensation or any other complication. Gamma Knife radiosurgery appears to be a minimally invasive, safe, and effective therapy of trigeminal neuralgia.

Gamma Knife stereotactic radiosurgical treatment of idiopathic trigeminal neuralgia: long-term outcome and complications

“…[4][5][6][12][13][14][15][30][31][32] The effect of the latency period after SRS in our study is comparable with the findings in previously reported series. 8,17,22,23,29,31 Interestingly, patients with previous surgery seem to be more frequently late responders to GKS than patients with no history of previous surgery. Our excellent and good outcome rates are comparable to those reported in previously published studies.…”

“…Although the observed differences in outcome did not reach levels of statistical significance in our study, a history of previous surgery has been previously identified as a negative prognostic factor. 1,8,17,23,24,31 Meticulous analysis of our pain outcome data revealed that the difference in the observed excellent outcome rates between patients who had and had not undergone previous surgeries became more profound as the time progressed, reaching a maximum at posttreatment Year 6. This finding may indicate that patients with no previous surgeries not only respond better to SRS treatment but maintain their excellent or good response longer than patients with a history of previous surgery; this parameter should be seriously considered in the surgical planning for SRS.…”

“…8,16 Numerous authors have reported on SRS with the GK, and outcome and complication rates have been variable. [1][2][3][4][5][6]8,[10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] The observed variation in success rates in the literature may be explained by the subjectivity of assessing pain (which is the most important outcome parameter in these studies), the multifactorial causes of TN (idiopathic or secondary to a pathological entity), the significantly varying stereotactic radiosurgical treatment protocols (different anatomical targets and different radiation doses), and the usage of illdefined and widely variable outcome assessment criteria.…”

Clinical, Anatomo-Radiological and Dosimetric Features Influencing Pain Outcome After Gamma Knife Treatment of Trigeminal Neuralgia

“…"Some agreement with a trend" indicates that atypical facial pain could responds worse to Gamma Knife treatment. (Young, 1997) reported 88% of pain relief in 9 patient treated targeting the tumor, Regis (Regis 2001), obtained pain cessation in 79.5% of 46 patients targeting the tumor, in 3 cases the target was the nerve and in 4 the target was the tumor with the nerve together. Pollock (Pollock, 2000) treated 23 patients (16 meningiomas and 8 malignant tumors).…”

Historical perspectives on the diagnosis and treatment of trigeminal neuralgia

“…33,69 The target has changed from the ganglion to the preganglionic root in the posterior fossa adjacent to the brainstem, which is the same area in which vascular compression is found. Concern remains about the time it takes for the treatment to achieve an effect.…”