Does increased nerve length within the treatment volume improve trigeminal neuralgia radiosurgery? A prospective double-blind, randomized study.

Flickinger JC, Pollock BE, Kondziolka D, Phuong LK, Foote RL, Stafford SL, Lunsford LD. Int J Radiat Oncol Biol Phys 2001 Oct 1;51(2):449-54

Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. jflickin@msx.upmc.edu

PURPOSE: To test the hypothesis that increasing the nerve length within the treatment volume for trigeminal neuralgia radiosurgery would improve pain relief. METHODS AND MATERIALS: Eighty-seven patients with typical trigeminal neuralgia were randomized to undergo retrogasserian gamma knife radiosurgery (75 Gy maximal dose with 4-mm diameter collimators) using either one (n = 44) or two (n = 43) isocenters. The median follow-up was 26 months (range 1-36). RESULTS: Pain relief was complete in 57 patients (45 without medication and 12 with low-dose medication), partial in 15, and minimal in another 15 patients. The actuarial rate of obtaining complete pain relief (with or without medication) was 67.7% +/- 5.1%. The pain relief was identical for one- and two-isocenter radiosurgery. Pain relapsed in 30 of 72 responding patients. Facial numbness and mild and severe paresthesias developed in 8, 5, and 1 two-isocenter patients vs. 3, 4, and 0 one-isocenter patients, respectively (p = 0.23). Improved pain relief correlated with younger age (p = 0.025) and fewer prior procedures (p = 0.039) and complications (numbness or paresthesias) correlated with the nerve length irradiated (p = 0.018). CONCLUSIONS: Increasing the treatment volume to include a longer nerve length for trigeminal neuralgia radiosurgery does not significantly improve pain relief but may increase complications.

Repeat radiosurgery for refractory trigeminal neuralgia.

Hasegawa T, Kondziolka D, Spiro R, Flickinger JC, Lunsford LD. Neurosurgery 2002 Mar;50(3):494-502

Departments of Neurological Surgery (TH, DK, RS, JCF, LDL), Radiation Oncology (DK, JCF, LDL), and Radiology (LDL), University of Pittsburgh School of Medicine, and the Center for Image-Guided Neurosurgery (TH, DK, RS, JCF, LDL), Pittsburgh, Pennsylvania.

OBJECTIVE: Stereotactic radiosurgery has become an important and minimally invasive alternative for patients with refractory trigeminal neuralgia. When a second procedure is necessary, the outcomes are unknown. The degree of pain relief and morbidity after repeat radiosurgery were studied. METHODS: Thirty-one patients underwent a second gamma knife radiosurgery procedure because of unsatisfactory or unsustained relief of pain after the first procedure. Twenty-seven patients were assessable at median follow-up periods of 42.7 and 20.4 months after the first and second procedures, respectively. Most patients had undergone multiple previous operations of other types (microvascular decompression, radiofrequency rhizotomy, glycerol rhizotomy, balloon compression). The median target doses of the first and second radiosurgeries were 75 and 64 Gy, respectively. All patients were evaluated by a physician who did not participate in patient treatment. RESULTS: After the first radiosurgical procedure, 13 patients had an excellent response initially (complete relief without any medication), 3 had a good response (complete relief with some medication), 7 had a fair response (>50% relief), and 4 had a poor response (<50% pain relief or treatment failure). Repeat radiosurgery was performed in patients with recurrent or residual pain. After the second radiosurgical procedure, 5 patients had an excellent response, 8 had a good response, 10 had a fair response, and 4 had a poor response. Thirteen patients (48%) achieved complete pain relief (with or without medication). Two patients (7.4%) experienced new sensory symptoms after the first radiosurgical procedure, and three (12.7%, actuarial) experienced new sensory symptoms after the second procedure. CONCLUSION: Repeat radiosurgery provided a similar rate of pain relief as the first procedure, despite a modest dose reduction. The risk of new sensory symptoms was increased, but no other morbidity was identified. For patients who experience recurrent pain and choose to undergo a second procedure, our current procedure is to deliver a maximum dose of 50 to 60 Gy to a trigeminal target anterior to the root entry zone near the entrance of the nerve beneath the petrous dura.

Gamma-knife radiosurgery for trigeminal neuralgia.

Kannan V, Deopujari CE, Misra BK, Shetty PG, Shroff MM, Pendse AM.  Australas Radiol 1999 Aug;43(3):339-41

PD Hinduja National Hospital and Medical Research Centre, Mumbai, India. dr_vkannan@hindujahospital.com

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70-80 Gy was delivered to the trigeminal root entry zone, 2-4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5-16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.

Gamma knife surgery for trigeminal neuralgia.

Kao MC. J Neurosurg 2002 Jan;96(1):160-1

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 radiosurgery as the first surgery for trigeminal neuralgia.

Kondziolka D, Lunsford LD, Flickinger JC.   Stereotact Funct Neurosurg 1998 Oct;70 Suppl 1:187-91

Departments of Neurological Surgery and Radiation Oncology, University of Pittsburgh, and the Center for Image Guided Neurosurgery, Pittsburgh, Pa., USA.

To evaluate the role of Gamma Knife radiosurgery as the first surgical therapy in the management of medically refractory trigeminal neuralgia, we reviewed outcomes on our first 23 patients who had radiosurgery as primary surgical therapy. These patients represented 19% of our overall series. Mean patient age was 66 years, and mean follow-up after radiosurgery was 12 months (range 5-33 months). For most patients, radiosurgery was performed because the patient had medical contraindications to open surgery. 14 patients had 70-Gy radiosurgery, and 9 patients, 80 Gy. Radiosurgery was performed using a single 4 mm isocenter. Postoperative imaging 6 to 9 months following radiosurgery confirmed regions of enhancement at the radiosurgical target. Nine patients received 70 Gy, and 8 patients had 80 Gy. 17 patients (74%) had an excellent result (total pain relief). Five patients (22%) achieved a good result (50-90% improvement). One patient had a poor result (4%) after 70-Gy radiosurgery and subsequently underwent microvascular decompression. No patient developed facial numbness or any other complication after Gamma Knife radiosurgery. Gamma Knife radiosurgery using 70 or 80 Gy targeted to the proximal trigeminal nerve proved to be a safe and effective primary surgical therapy for medically refractory trigeminal neuralgia. The overall response rate (96%) was similar to that obtained with other surgical therapies performed as a first procedure.

Clinical outcomes after stereotactic radiosurgery for idiopathic trigeminal neuralgia.

Maesawa S, Salame C, Flickinger JC, Pirris S, Kondziolka D, Lunsford LD. J Neurosurg 2001 Jan;94(1):14-20

Department of Neurological Surgery, University of Pittsburgh, Pennsylvania, USA.

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 deafferentation 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 radiosurgery using 90 Gy for trigeminal neuralgia.

Nicol B, Regine WF, Courtney C, Meigooni A, Sanders M, Young B.  J Neurosurg 2000 Dec;93 Suppl 3:152-4

Department of Radiation Medicine, University of Kentucky, Lexington, 40506, USA. bnico0@pop.uky.edu

OBJECT: The purpose of this paper was to assess the treatment of trigeminal neuralgia (TN) with the higher than normal dose of 90 Gy. METHODS: Forty-two patients with typical TN were treated over a 3-year period with gamma knife radiosurgery. Every patient received a maximum dose of 90 Gy in a single 4-mm isocenter targeted to the root entry zone of the trigeminal nerve. Thirty of 42 patients had undergone no prior treatments. The median follow-up period was 14 months (range 2-30 months). Thirty-one patients (73.8%) achieved complete relief of pain. Nine patients (21.4%) obtained good pain control. Complications were limited to increased facial paresthesia in seven patients (16.7%) and dysgeusia in four patients (9.5%). CONCLUSIONS: The authors conclude that the use of 90 Gy is a safe and effective dose for the treatment of TN.

High-dose trigeminal neuralgia radiosurgery associated with increased risk of trigeminal nerve dysfunction.

Pollock BE, Phuong LK, Foote RL, Stafford SL, Gorman DA.  Neurosurgery 2001 Jul;49(1):58-62;

Department of Neurological Surgery, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA. pollock.bruce@mayo.edu

OBJECTIVE: Stereotactic radiosurgery is being used with more frequency in the management of patients with trigeminal neuralgia. To improve facial pain outcomes, many centers have increased the prescribed radiation dose to the trigeminal nerve. METHODS: Between April 1997 and December 1999, 68 patients underwent radiosurgery for trigeminal neuralgia with use of the Leksell gamma knife (Elekta Instruments, Norcross, GA) and a single 4-mm isocenter of radiation. Twenty-seven patients (40%) received 70 Gy (low dose) of irradiation and 41 patients (60%) received 90 Gy (high dose). The groups were similar with regard to age, sex, duration of pain, number of prior surgeries, and preexisting trigeminal deficits. The primary facial pain outcomes for analysis were excellent (pain-free, no medications) and good (pain-free, reduced medications). The mean length of follow-up after radiosurgery was 14.4 months (range, 2-36 mo). RESULTS: At last follow-up examination, 11 (41%) of the 27 patients with low-dose radiosurgery remained pain-free compared with 25 (61%) of the 41 patients with high-dose radiosurgery (P = 0.17). Additional surgery was performed in 12 low-dose patients (44%) and 8 high-dose patients (20%) (P = 0.05). High-dose radiosurgery was associated with an increased rate of permanent trigeminal nerve dysfunction (54% versus 15%, P = 0.003). Bothersome dysesthesias occurred in 13 high-dose patients (32%), whereas only 1 low-dose patient had this complication (P = 0.01). Three high-dose patients (8%) developed corneal numbness after radiosurgery. Pain recurred with more frequency in patients not developing trigeminal nerve dysfunction after radiosurgery (9 of 22 patients, 41 %) compared with those who sustained facial numbness, paresthesias, or dysesthesias (4 of 27 patients, 15%); however, the difference was not statistically significant (P = 0.08). CONCLUSION: Higher doses of radiation may correlate with better facial pain outcomes after radiosurgery for trigeminal neuralgia. However, the incidence of significant trigeminal nerve dysfunction is markedly increased after radiosurgery for patients receiving high-dose radiosurgery. Because of the nonselective nature of this ablative technique, dose prescription should be limited to less than 90 Gy.

Results of repeated gamma knife radiosurgery for medically unresponsive trigeminal neuralgia.

Pollock BE, Foote RL, Stafford SL, Link MJ, Gorman DA, Schomberg PJ.  J Neurosurg 2000 Dec;93 Suppl 3:162-4

Department of Neurological Surgery, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA. pollock.bruce@mayo.edu

OBJECT: Gamma knife radiosurgery (GKS) is being increasing performed in the management of patients with medically unresponsive trigeminal neuralgia. The authors report the results of repeated GKS in patients with recurrent facial pain after their initial procedure. METHODS: Between April 1997 and December 1999, 100 patients with idiopathic trigeminal neuralgia underwent GKS at the authors' center. To date, 26 patients have required additional surgery because GKS provided no significant pain relief (15 patients) or because they had recurrent facial pain (11 patients). Ten of these patients underwent repeated GKS at a median of 13 months (range 4-27 months). All patients undergoing repeated GKS had a significant reduction in their facial pain after the first procedure (eight were pain free); no patient developed facial numbness or paresthesias. Initially, nine of 10 patients became pain free 1 to 4 weeks following repeated GKS. At a median follow up of 15 months (range 3-32 months), eight patients remained pain free and required no medication. All eight patients with persistent pain relief developed minor neurological dysfunction after repeated GKS (six patients had facial numbness and two had paresthesias). CONCLUSIONS: Repeated GKS can be associated with a high rate of pain relief for patients with trigeminal neuralgia who experienced a significant reduction in their facial pain after the first operation. However, every patient with sustained pain relief after the second operation also developed some degree of trigeminal dysfunction. These findings of improved pain relief for patients who develop facial numbness after GKS for trigeminal neuralgia support the experimental data currently available.

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

Regis J, Metellus P, Dufour H, Roche PH, Muracciole X, Pellet W, Grisoli F, Peragut JC.    J Neurosurg 2001 Aug;95(2):199-205

Department of Stereotactic and Functional Neurosurgery, Timone Hospital, Marseilles, France.

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.

Gamma knife radiosurgery for trigeminal neuralgia: the initial experience of The Barrow Neurological Institute.

Rogers CL, Shetter AG, Fiedler JA, Smith KA, Han PP, Speiser BL. Int J Radiat Oncol Biol Phys 2000 Jul 1;47(4):1013-9

St. Joseph's Hospital and Barrow Neurological Institute, Phoenix, AZ, USA. lelandroge@aol.com

A total of 557 patients have been treated, 89 for trigeminal neuralgia (TN). This report includes the first 54 TN patients with follow-up exceeding 3 months. Patients were treated with Gamma Knife stereotactic radiosurgery (RS) in uniform fashion according to two sequential protocols. The first 41 patients received 35 Gy prescribed to the 50% isodose via a single 4-mm isocenter targeting the ipsilateral trigeminal nerve adjacent to the pons. The dose was increased to 40 Gy for the remaining 13 patients; however, the other parameters were unvaried. Outcome was evaluated by each patient using a standardized questionnaire. Pain before and after RS was scored as level I-IV per our newly-developed BNI pain intensity scoring criteria (I: no pain; II: occasional pain, not requiring medication; III: some pain, controlled with medication; IV: some pain, not controlled with medication; V: severe pain/no pain relief). Complications, limited to mild facial numbness, were similarly graded by a BNI scoring system. RESULTS: Among our 54 TN patients, 52 experienced pain relief, BNI score I in 19 (35%), II in 3 (6%), III in 26 (48%), and IV in 4 (7%). Two patients (4%) reported no relief (BNI score V). Median follow-up was 12 months (range 3-28). Median time to onset of pain relief was 15 days (range 0-192), and to maximal relief 63 days (range 0-253). Seventeen (31%) noted immediate improvement (</= 24 h). Prior to RS, all patients were on pharmacologic therapy felt to be optimal or maximal. Twenty-two (41%) were able to stop medications entirely (BNI score I or II). Another 16 (30%), with BNI Score III relief, decreased medication intake by at least 50%. Patients with classical TN pain symptoms were more likely to stop medications than those with atypical features, 49% (21 of 43) versus 9% (1 of 11). This difference was significant at p = 0.040. Statistically, the finding most predictive for pain relief was new facial numbness following RS. Each of the 5 patients with new numbness after RS developed BNI score I relief, contrasting with 35% for the 49 patients with no new numbness (p = 0.019). Complications have been limited to delayed, mild facial sensory loss. Before RS, 17 patients had numbness from prior invasive procedures, none of whom reported a worse numbness score after treatment. Thirty-seven patients had no facial numbness at the time of RS, of whom 5 developed facial hypesthesia. Each rated this as "mild, not bothersome." There have been no other sequellae. CONCLUSION: RS is an effective treatment, and is the least invasive nonpharmacologic therapy for TN. It carries a small risk of mild facial hypesthesia, a side effect which, somewhat ironically, may be desirable, because it appears to correlate favorably with an excellent pain response. We currently include radiosurgery among the appropriate options for TN patients who have failed optimal medical management, with or without prior invasive neurosurgical procedures. We present here BNI scoring systems for pain intensity and facial numbness. These have proved simple and reliable, have facilitated data collection, rendered analysis more objective, and improved our ability to discuss results with patients and colleagues.

Treatment of postherpetic trigeminal neuralgia with the gamma knife.

Urgosik D, Vymazal J, Vladyka V, Liscak R. J Neurosurg 2000 Dec;93 Suppl 3:165-8

Department of Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague, Czech Republic. urgo@zero.cz

OBJECT: Postherpetic neuralgia is a syndrome characterized by intractable pain. Treatment of this pain has not yet been successful. Patients with postherpetic neuralgia will therefore benefit from any progress in the treatment strategy. The authors performed gamma knife radiosurgery (GKS) as a noninvasive treatment for postherpetic trigeminal neuralgia (TN) and evaluated the success rate for pain relief. METHODS: Between 1995 and February 1999, six men and 10 women were treated for postherpetic TN; conservative treatment failed in all of them. The median follow up was 33 months (range 8-34 months). The radiation was focused on the root of the trigeminal nerve in the vicinity of the brainstem (maximal dose 70-80 Gy in one fraction, 4-mm collimator). The patients were divided into five groups according to degree of pain relief after treatment. A successful result (excellent, very good, and good) was reached in seven (44%) patients and radiosurgery failed in nine (56%). Pain relief occurred after a median interval of 1 month (range 10 days-6 months). No radiation-related side effects have been observed in these patients. CONCLUSIONS: These results suggest that GKS for postherpetic TN is a relatively successful and safe method that can be used in patients even if they are in poor condition. In case this method fails, other treatment options including other neurosurgical procedures are not excluded.