Does dose rate affect efficacy? The outcomes of 256 Gamma Knife surgery procedures for trigeminal neuralgia and other types of facial pain as they relate to the half-life of cobalt

2006 ◽  
Vol 105 (5) ◽  
pp. 730-735 ◽  
Author(s):  
Christopher J. Balamucki ◽  
Volker W. Stieber ◽  
Thomas L. Ellis ◽  
Stephen B. Tatter ◽  
Allan F. DeGuzman ◽  
...  
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Dose Rate ◽  
Gamma Knife ◽  
Half Life ◽  
Pain Control ◽  
Facial Pain ◽  
Treatment Time ◽  
Gamma Knife Surgery ◽  
Chi Square

Object Gamma Knife surgery (GKS) is a treatment option for patients with refractory typical trigeminal neuralgia (TN), TN with atypical features, and atypical types of facial pain. The Gamma Knife’s 201 60Co sources decay with a half-life of 5.26 years. The authors examined whether the decrease in dose rate over 4.6 years between Co source replacements affected the control rates of facial pain in patients undergoing GKS. Methods The authors collected complete follow-up data on 239 of 326 GKS procedures performed in patients with facial pain. Patients were classified by their type of pain. The isocenter of a 4-mm collimator helmet was targeted at the proximal trigeminal nerve root, and the dose (80–90 Gy) was prescribed at the 100% isodose line. Patients reported the amount of pain control following radiosurgery by answering a standardized questionnaire. Eighty percent of patients experienced greater than 50% pain relief, and 56% of patients experienced complete pain relief after GKS. Neither dose rate nor treatment time was significantly associated with either the control rate or degree of pain relief. A significant association between the type of facial pain and the pain control rate after GKS was observed (p < 0.001; Pearson chi-square test). In their statistical analysis, the authors accounted for changes in prescription dose over time to prevent the dose rate from being a confounding variable. There was no observable effect of the dose rate or of the treatment duration within the typical period to source replacement. Conclusions Patients with facial pain appear to receive consistent treatment with GKS at any time during the first half-life of the Co sources.

scholarly journals Assessment of pain control, quality of life, and predictors of success after gamma knife surgery for the treatment of trigeminal neuralgia

2005 ◽  
Vol 18 (5) ◽  
pp. 1-7 ◽  
Author(s):  
Ajay Jawahar ◽  
Rishi Wadhwa ◽  
Caglar Berk ◽  
Gloria Caldito ◽  
Allyson Delaune ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Patient Satisfaction ◽  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Gamma Knife Surgery ◽  
Patient Satisfaction Score

Object There are various surgical treatment alternatives for trigeminal neuralgia (TN), but there is no single scale that can be used uniformly to assess and compare one type of intervention with the others. In this study the objectives were to determine factors associated with pain control, pain-free survival, residual pain, and recurrence after gamma knife surgery (GKS) treatment for TN, and to correlate the patients' self-reported quality of life (QOL) and satisfaction with the aforementioned factors. Methods Between the years 2000 and 2004, the authors treated 81 patients with medically refractory TN by using GKS. Fifty-two patients responded to a questionnaire regarding pain control, activities of daily living, QOL, and patient satisfaction. The median follow-up duration was 16.5 months. Twenty-two patients (42.3%) had complete pain relief, 14 (26.9%) had partial but satisfactory pain relief, and in 16 patients (30.8%) the treatment failed. Seven patients (13.5%) reported a recurrence during the follow-up period, and 25 (48.1%) reported a significant (> 50%) decrease in their pain within the 1st month posttreatment. The mean decrease in the total dose of pain medication was 75%. Patients' self-reported QOL scores improved 90% and the overall patient satisfaction score was 80%. Conclusions The authors found that GKS is a minimally invasive and effective procedure that yields a favorable outcome for patients with recurrent or refractory TN. It may also be offered as a first-line surgical modality for any patients with TN who are unsuited or unwilling to undergo microvascular decompression.

Outcomes of Gamma Knife surgery for trigeminal neuralgia secondary to vertebrobasilar ectasia

2012 ◽  
Vol 116 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Kyung-Jae Park ◽  
Douglas Kondziolka ◽  
Hideyuki Kano ◽  
Oren Berkowitz ◽  
Safee Faraz Ahmed ◽  
...  
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Trigeminal Nerve ◽  
Pain Control ◽  
Invasive Procedure ◽  
Gamma Knife Surgery ◽  
Vascular Compression ◽  
Recurrent Pain

Object Vertebrobasilar ectasia (VBE) is an unusual cause of trigeminal neuralgia (TN). The surgical options for patients with medically refractory pain include percutaneous or microsurgical rhizotomy and microvascular decompression (MVD). All such procedures can be technically challenging. This report evaluates the response to a minimally invasive procedure, Gamma Knife surgery (GKS), in patients with TN associated with severe vascular compression caused by VBE. Methods Twenty patients underwent GKS for medically refractory TN associated with VBE. The median patient age was 74 years (range 48–95 years). Prior surgical procedures had failed in 11 patients (55%). In 9 patients (45%), GKS was the first procedure they had undergone. The median target dose for GKS was 80 Gy (range 75–85 Gy). The median follow-up was 29 months (range 8–123 months) after GKS. The treatment outcomes were compared with 80 case-matched controls who underwent GKS for TN not associated with VBE. Results Intraoperative MR imaging or CT scanning revealed VBE that deformed the brainstem in 50% of patients. The trigeminal nerve was displaced in cephalad or lateral planes in 60%. In 4 patients (20%), the authors could identify only the distal cisternal component of the trigeminal nerve as it entered into the Meckel cave. After GKS, 15 patients (75%) achieved initial pain relief that was adequate or better, with or without medication (Barrow Neurological Institute [BNI] pain scale, Grades I–IIIb). The median time until pain relief was 5 weeks (range 1 day–6 months). Twelve patients (60%) with initial pain relief reported recurrent pain between 3 and 43 months after GKS (median 12 months). Pain relief was maintained in 53% at 1 year, 38% at 2 years, and 10% at 5 years. Some degree of facial sensory dysfunction occurred in 10% of patients. Eventually, 14 (70%) of the 20 patients underwent an additional surgical procedure including repeat GKS, percutaneous procedure, or MVD at a median of 14 months (range 5–50 months) after the initial GKS. At the last follow-up, 15 patients (75%) had satisfactory pain control (BNI Grades I–IIIb), but 5 patients (25%) continued to have unsatisfactory pain control (BNI Grade IV or V). Compared with patients without VBE, patients with VBE were much less likely to have initial (p = 0.025) or lasting (p = 0.006) pain relief. Conclusions Pain control rates of GKS in patients with TN associated with VBE were inferior to those of patients without VBE. Multimodality surgical or medical management strategies were required in most patients with VBE.

Gamma Knife surgery for recurrent or residual trigeminal neuralgia after a failed initial procedure

2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 172-177 ◽  
Author(s):  
Chuan-Fu Huang ◽  
Shyh-Ying Chiou ◽  
Ming-Fang Wu ◽  
Hsien-Tang Tu ◽  
Wen-Shan Liu
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Initial Treatment ◽  
Gamma Knife Surgery ◽  
Significant Difference ◽  
Facial Numbness ◽  
Initial Procedure

Object The purpose of this study was to assess outcomes of Gamma Knife surgery (GKS) as a second treatment for recurrent or residual trigeminal neuralgia (TN) after failure of 3 initial procedures: microvascular decompression (MVD), GKS, and percutaneous radiofrequency rhizotomy (PRR). Methods Between 1999 and 2008, 65 patients (31 men [48%] and 34 women [52%]) with recurrent TN were treated with GKS. All 65 patients had undergone previous medical procedures that failed to achieve sufficient pain relief: 27 patients (42%) had undergone MVD, 8 (12%) had undergone PRR, and 30 (46%) had undergone GKS as the initial treatment. The entry zone of the trigeminal nerve was targeted using a 4-mm collimator and treated with 35–90 Gy. The isocenter was positioned so that the brainstem surface was usually irradiated at an isodose no greater than 20% (59 patients) to 30% (6 patients). The median duration of TN symptoms in these patients was 39 months (range 1–192 months). Results At the clinical evaluation, 42 patients (65%) with idiopathic TN reported successful pain control at a median follow-up point of 64 months (range 18–132 months). Of these patients, 33 (51%) were no longer using medication. At the 1-, 2-, and 3-year follow-up examinations, 74%, 71%, and 66% of patients experienced successful pain control, respectively. There was no significant difference in pain relief in the initial MVD group compared with the initial GKS and initial PRR groups (74% vs 59% and 50%, respectively; p = 0.342). Recurrence of pain was noted in 23 patients. Twelve of these 23 patients underwent another GKS, resulting in pain control in 8 patients (67%); 8 other patients underwent MVD, resulting in pain relief in 7 patients (87.5%). The median time from GKS to pain recurrence was 7 months (range 3–48 months). There was no significant difference in new facial numbness among the 3 groups (p = 0.24); however, in the initial GKS group, facial numbness was significantly associated with freedom from pain (p = 0.0012). There was a significant correlation between the total radiation dose and facial numbness. The cutoff value for facial numbness ranged from 115 to 120 Gy (p = 0.037). Conclusions Gamma Knife surgery as a second treatment achieved acceptable levels of pain control in 65% of patients with residual or recurrent TN after long-term follow-up. Initial treatment was not a factor that affected pain control, but salvage surgery may be considered separately for each group.

scholarly journals Comparative study of Gamma Knife surgery and percutaneous retrogasserian glycerol rhizotomy for trigeminal neuralgia in patients with multiple sclerosis

2012 ◽  
Vol 117 (Special_Suppl) ◽  
pp. 175-180 ◽  
Author(s):  
David Mathieu ◽  
Khaled Effendi ◽  
Jocelyn Blanchard ◽  
Mario Séguin
Keyword(s):  
Multiple Sclerosis ◽  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Pain Scale ◽  
Gamma Knife Surgery ◽  
Sensory Loss ◽  
Morbidity Rate

Object Among patients with multiple sclerosis (MS) there is a high incidence of trigeminal neuralgia (TN), and outcomes after treatment seem inferior to those in patients suffering from idiopathic TN. The goal of this study was to evaluate clinical outcomes in patients with MS-related TN after Gamma Knife surgery (GKS) and compare them with those obtained using percutaneous retrogasserian glycerol rhizotomy (PRGR). Methods The authors retrospectively reviewed the charts of 45 patients with MS-related TN. The first procedure undertaken was GKS in 27 patients and PRGR in 18 patients. Pain had been present for a median of 60 months (range 12–276 months) in patients who underwent GKS and 48 months (range 12–240 months) in patients who underwent PRGR. The following outcome measures were assessed in both groups of patients: pain relief (using the Barrow Neurological Institute [BNI] Pain Scale), procedure-related morbidity, time to pain relief and recurrence, and subsequent procedures that were performed. Results The median duration of follow-up was 39 months (range 13–69 months) in the GKS group and 38 months (range 2–75 months) in the PRGR group. Reasonable pain control (BNI Pain Scale Scores I–IIIb) was noted in 22 patients (81.5%) who underwent GKS and in 18 patients (100%) who underwent PRGR. For patients who underwent GKS, the median time to pain relief was 6 months; for those who underwent PRGR, pain relief was immediate. In the GKS group12 patients required subsequent procedures (3 patients for absence of response and 9 patients for pain recurrence), whereas in the PRGR group 6 patients required subsequent procedures (all for pain recurrence). As of the last follow-up, complete or reasonable pain control was finally achieved in 23 patients (85.2%) in the GKS group and in 16 patients (88.9%) in the PRGR group. The morbidity rate was 22.2% in the GKS group (all due to sensory loss and paresthesia) and 66.7% in the PRGR group (mostly hypalgesia, with 2 patients having corneal reflex loss and 1 patient suffering from meningitis). Conclusions Both GKS and PRGR are satisfactory strategies for treating MS-related TN. Gamma Knife surgery has a lower rate of sensory and overall morbidity than PRGR, but requires a delay before pain relief occurs. The authors propose that patients with extreme pain in need of fast relief should undergo PRGR. For other patients, both management strategies can lead to satisfactory pain relief, and the choice should be made based on patient preference and expectations.

scholarly journals Clinical Outcomes of Gamma Knife Radiosurgery in the Treatment of Patients with Trigeminal Neuralgia

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Ameer L. Elaimy ◽  
Peter W. Hanson ◽  
Wayne T. Lamoreaux ◽  
Alexander R. Mackay ◽  
John J. Demakas ◽  
...  
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Facial Pain ◽  
Gamma Knife Radiosurgery ◽  
Management Approach ◽  
Review Of The Literature ◽  
Facial Numbness ◽  
Sensory Changes

Since its introduction by Leksell, Gamma Knife radiosurgery (GKRS) has become increasingly popular as a management approach for patients diagnosed with trigeminal neuralgia (TN). For this reason, we performed a modern review of the literature analyzing the efficacy of GKRS in the treatment of patients who suffer from TN. For patients with medically refractory forms of the condition, GKRS has proven to be an effective initial and repeat treatment option. Cumulative research suggests that patients treated a single time with GKRS exhibit similar levels of facial pain control when compared to patients treated multiple times with GKRS. However, patients treated on multiple occasions with GKRS are more likely to experience facial numbness and other facial sensory changes when compared to patients treated once with GKRS. Although numerous articles have reported MVD to be superior to GKRS in achieving facial pain relief, the findings of these comparison studies are weakened by the vast differences in patient age and comorbidities between the two studied groups and cannot be considered conclusive. Questions remain regarding optimal GKRS dosing and targeting strategies, which warrants further investigation into this controversial matter.

Does the Gamma Knife dose rate affect outcomes in radiosurgery for trigeminal neuralgia?

2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 168-171 ◽  
Author(s):  
Yoshio Arai ◽  
Hideyuki Kano ◽  
L. Dade Lunsford ◽  
Josef Novotny ◽  
Ajay Niranjan ◽  
...  
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Dose Rate ◽  
Gamma Knife ◽  
Pain Control ◽  
Radiation Treatment ◽  
Irradiation Time ◽  
High Dose ◽  
Radiation Dose Rate ◽  
Significant Difference

Object The object of this study was to determine whether the radiation dose rate affects clinical outcomes in patients who undergo stereotactic Gamma Knife surgery (GKS) to manage typical trigeminal neuralgia (TN). Methods The authors retrospectively studied pain relief in 165 patients with medically intractable TN, who underwent 80-Gy GKS using a single 4-mm collimator between 1994 and 2005. No patient had received prior radiation treatment. The measured relative helmet output factor of the Gamma Knife was 0.8 throughout this interval, and the dose rate varied from 1.21 Gy/minute to 3.74 Gy/minute (median 2.06 Gy/minute). Irradiation time varied from 26.73 to 95.11 minutes. The authors divided patients into a low-dose-rate (LDR) group, in which the dose rate varied from 1.21 to 2.05 Gy/minute, and a high-dose-rate (HDR) group, in which the dose rate varied from 2.06 to 3.74 Gy/minute. Post-GKS, the patients' pain control was determined using the Barrow Neurological Institute (BNI) pain scale. There was no statistically significant difference between groups with respect to history of prior microvascular decompression (p = 0.410) or peripheral neuroablative procedures (p = 0.583). The length of symptoms in patients varied from 3 to 414 months with a median of 84 months (p = 0.698). Median follow-up was 26 months with a maximum of 139 months. Results Initial pain relief was obtained in 71% of patients in the LDR group and 78% in the HDR group (p = 0.547). Patients who initially obtained improved pain relief (BNI Scores I–IIIa) after GKS maintained pain control for median durations of 52 months (LDR group) and 54 months (HDR group) (p = 0.403). New or increased facial sensory dysfunction was found in 14.5% of patients in the LDR group and in 19.3% of patients in the HDR group (p = 0.479). Conclusions The authors found that the GKS dose rate did not affect pain control or morbidity within the range of 1.21–3.74 Gy/minute. Cobalt 60 source decay did not affect outcomes of GKS for TN pain management, even for dose rates approximating a 2-half-life decay of the isotope.

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

2001 ◽  
Vol 95 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Jean Régis ◽  
Philippe Metellus ◽  
Henry Dufour ◽  
Pierre-Hughes Roche ◽  
Xavier Muracciole ◽  
...  
Keyword(s):  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Facial Pain ◽  
Group Iv ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Prepontine Cistern ◽  
Fine Print

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.

Outcome Predictors After Gamma Knife Radiosurgery for Recurrent Trigeminal Neuralgia

Neurosurgery ◽  
2010 ◽  
Vol 67 (6) ◽  
pp. 1637-1645 ◽  
Author(s):  
Hideyuki Kano ◽  
Douglas Kondziolka ◽  
Huai-Che Yang ◽  
Oscar Zorro ◽  
Javier Lobato-Polo ◽  
...  
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Surgical Procedure ◽  
Gamma Knife Radiosurgery ◽  
Sensory Loss ◽  
Failed Surgery ◽  
Gamma Knife Stereotactic Radiosurgery

Abstract BACKGROUND: Trigeminal neuralgia (TN) that recurs after surgery can be difficult to manage. OBJECTIVE: To define management outcomes in patients who underwent gamma knife stereotactic radiosurgery (GKSR) after failing 1 or more previous surgical procedures. METHODS: We retrospectively reviewed outcomes after GKSR in 193 patients with TN after failed surgery. The median patient age was 70 years (range, 26-93 years). Seventy-five patients had a single operation (microvascular decompression, n = 40; glycerol rhizotomy, n = 24; radiofrequency rhizotomy, n = 11). One hundred eighteen patients underwent multiple operations before GKSR. Patients were evaluated up to 14 years after GKSR. RESULTS: After GKSR, 85% of patients achieved pain relief or improvement (Barrow Neurological Institute grade I-IIIb). Pain recurrence was observed in 73 of 168 patients 6 to 144 months after GKSR (median, 6 years). Factors associated with better long-term pain relief included no relief from the surgical procedure preceding GKSR, pain in a single branch, typical TN, and a single previous failed surgical procedure. Eighteen patients (9.3%) developed new or increased trigeminal sensory dysfunction, and 1 developed deafferentation pain. Patients who developed sensory loss after GKSR had better long-term pain control (Barrow Neurological Institute grade I-IIIb: 86% at 5 years). CONCLUSION: GKSR proved to be safe and moderately effective in the management of TN that recurs after surgery. Development of sensory loss may predict better long-term pain control. The best candidates for GKSR were patients with recurrence after a single failed previous operation and those with typical TN in a single trigeminal nerve distribution.

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

2004 ◽  
Vol 100 (5) ◽  
pp. 848-854 ◽  
Author(s):  
Ronald Brisman
Keyword(s):  
Pain Relief ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Recurrent Pain ◽  
Content Type ◽  
Kaplan Meier ◽  
Uniform Manner ◽  
Second Procedure ◽  
Fine Print

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.

Comparison of the results of 2 targeting methods in Gamma Knife surgery for trigeminal neuralgia

2008 ◽  
Vol 109 (Supplement) ◽  
pp. 185-189 ◽  
Author(s):  
Shinji Matsuda ◽  
Toru Serizawa ◽  
Osamu Nagano ◽  
Junichi Ono
Keyword(s):  
Complete Remission ◽  
Trigeminal Neuralgia ◽  
Gamma Knife ◽  
Pain Control ◽  
Gamma Knife Surgery ◽  
Root Entry Zone ◽  
Posterior Group ◽  
Anterior Group ◽  
Free Status

Object Gamma Knife surgery (GKS) is an effective treatment for intractable trigeminal neuralgia (TN). The authors compared results using two major GKS target points, the dorsal root entry zone and the retrogasserian portion, in a series of patients with intractable TN. Methods One hundred patients with medically refractory TN underwent GKS between August 1998 and December 2007. Thirty-seven were men, and 63 were women. The median age at GKS was 74 years. With a single isocenter and use of a 4mm collimator, 51 patients received 80 Gy at the proximal trigeminal nerve (posterior group) and 7 patients received 80 Gy, 1 patient received 85 Gy, and 41 patients received 90 Gy at the retrogasserian portion (anterior group). Follow-up was obtained by clinic visits every 3–6 months after GKS. Data on pain control, complications, and pain recurrence were recorded. The relationships between pain control status, complications, recurrence, and the target portions (anterior vs posterior) were analyzed. Results The median duration of follow-up was 30 months (range 3–88 months). Initially, 87 patients achieved pain-free status and 64 achieved complete remission. At the final follow-up visit, 68 patients were still in pain-free status and 42 were in complete remission. Recurrence of facial pain occurred in 15 patients. Forty-one patients developed some degree of trigeminal dysfunction. The rate of initial complete remission was higher in the posterior group than in the anterior group (p = 0.003). More complications were observed in the anterior group than in the posterior group (p = 0.009). Conclusions The posterior targeting group had better pain control and a lower complication rate. The authors recommend the posterior targeting method and use of 80 Gy for treatment of TN with GKS.

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