Gamma Knife radiosurgery for multiple sclerosis-associated trigeminal neuralgia.

BACKGROUND: Gamma Knife radiosurgery (GKRS) has well-known efficacy in the treatment of idiopathic trigeminal neuralgia (TN). However, few studies have evaluated the effects of GKRS in the treatment of multiple sclerosis (MS)-related TN. This study analyzed the efficacy and complications of GKRS for MS-related TN. METHODS: This retrospective study included 28 MS-related TN patients who underwent GKRS with a median follow-up of 27 (range, 12-181) months. The cisternal segment of the trigeminal nerve was targeted with a median radiation dose of 80 (80-90) Gy. Pain intensity was assessed using Barrow Neurological Institute (BNI)-Pain Intensity Scores (BNI-PIS). Before GKRS, all patients suffered from BNI pain levels of 4 or 5. A reduction in pain to BNI 3b or below was deemed as adequate pain relief. RESULTS: The initial proportion of patients who experienced adequate pain relief was 71.4%, with a median interval of 21 (1-45) days. At the final follow-up, 50% of patients had achieved adequate pain relief. Ten patients (35.7%) suffered from complications, including four with facial sensorial dysfunctions, four with a decline in their corneal reflexes, and two with jaw weakness. Among the 20 initial responders, six (30%) patients suffered pain recurrence after a median interval of 35 (12-180) months. CONCLUSIONS: GKRS is an effective means of pain relief in MS-related TN, but has side effects that are relevant to other ablative treatments. The benefits and risks of GKRS should be discussed with patients who wish to avoid surgery or when previous treatments fail.

[Frameless trigeminal neuralgia radiosurgery with a dedicated linear accelerator: From equipment commissioning to initial clinical results]. / Radiochirurgie des névralgies trigéminales avec accélérateur linéaire dédié sans cadre invasif : de la mise en service de l'appareil aux premiers résultats cliniques.

PURPOSE: Radiosurgery for the treatment of trigeminal neuralgia delivers a very high dose in a single fraction, over a few millimeters, at a single isocenter placed along the nerve. We present here the different steps that have been performed to validate small beams by conical collimators, and report the clinical results of the first patients treated on Novalis Tx®, frameless. MATERIAL AND METHODS: First, the geometric accuracy of 4 and 6mm conical collimators was evaluated using Winston-Lutz tests; then dosimetric data acquisition was performed using high spatial resolution detectors (PTW 60019 microdiamond and a PTW 60017 E-diode). The corrective factors of the TRS 483 report were applied to calculate the collimator aperture factors. These dosimetric data were then compared with the data implemented in the iPlan® treatment planning system. Then end-to-end tests were performed to control the entire treatment process using an anthropomorphic phantom "STEEV". Between 2020 and 2022, 18 patients were treated for refractory trigeminal neuralgia on Novalis Tx®, frameless, with Exactrac® repositioning. A total of 17 patients were evaluated (one was lost to follow-up) using the BNI score for pain assessment and MRI with a median follow-up of 12 months. RESULTS: The quality criteria of geometric and dosimetric accuracy were met for the 6-mm cone but not for the 4-mm cone. All patients were treated with a 6-mm cone with a dose of 90Gy prescribed at the isocenter at the root entry zone. Initial pain control was obtained in 70.5% of our patients, and 53% maintained pain control with a median follow-up of 12 months. All recurrences occurred within 3 to 6 months after radiosurgery. No brainstem toxicity was observed. Six patients had non-disabling facial hypoesthesia, half of whom already had pretreatment hypoesthesia. CONCLUSION: The treatment of trigeminal neuralgia on a dedicated linear accelerator is a highly technical treatment whose accuracy and safety are paramount. The physical measurements allowed the commissioning of the technique with a 6mm cone. Our first clinical results are in accordance with the literature.

Radiosurgical Decompression of Trigeminal Nerve and Its Correlation with Functional Outcome in Tumor-Related Trigeminal Neuralgia.

BACKGROUND: Target selection during Gamma Knife radiosurgery (GKRS) in cases of tumor-related trigeminal neuralgia is always debatable. We analyzed the correlation of regression of tumor size and degree of release of the nerve with long-term pain control. METHODS: Between March 2012 and March 2023, 50 cases of tumor-related trigeminal neuralgia were treated with GKRS (tumor was targeted). Radiological findings after GKRS were categorized into 3 types: 1) tumor volume remained same or decreased, additional segment of nerve not seen; 2) tumor volume decreased, additional segment of trigeminal nerve seen, but tumor still adherent to the nerve; 3) tumor volume decreased, adjacent nerve seen completely separated from tumor. Pain score before and after GKRS (Barrow Neurological Institute I-III: good; Barrow Neurological Institute IV and V: poor) was correlated with these subgroups. RESULTS: At median follow-up of 46.5 months, 18 cases showed type 1 radiological response, 23 showed type 2 response, and 9 showed type 3 response. Good pain control was achieved in 10 (55.5%) patients with type 1, 15 (65.21%) with type 2, and 7 (77.8%) with type 3 responses. The outcome differences among these 3 groups were not statistically significant (P = 0.519). Five patients with type 3 radiological response were off medication, which was statistically better than type 1 and type 2 radiological responses, with 3 patients (P = 0.012) and 2 patients (P = 0.002), respectively, still receiving medication. CONCLUSIONS: Tumor volume reduction after GKRS may be associated with good pain control in tumor-related trigeminal neuralgia. Further, this allows visualization of additional segment of nerve that can be targeted in a second session for treating recurrent or failed cases.

Pain Relief-Related Structural Brain Alterations in Trigeminal Neuralgia Induced by Noninvasive Stereotactic Radiosurgery: A Pilot Study.

PURPOSE: Trigeminal neuralgia (TN) is a chronic pain disorder defined by unilateral shock-like pain in at least one division of the trigeminal nerve. Although several studies have investigated structural brain plasticity in patients with TN, treatment-induced alterations remain largely uninvestigated. METHODS AND MATERIALS: Combining T1-weighted magnetic resonance imaging with voxel-based morphometry and multiple-regression analyses, we assessed gray matter maps of patients with TN to investigate changes in gray matter volume (GMV) before and 6 months after stereotactic radiosurgery (SRS). RESULTS: Comparison of pre- and post-SRS GMV of 25 patients with TN (16 women; mean age 67 years) did not yield any significant clusters, suggesting that the effect of SRS intervention itself on gray matter structure may be negligible. Regarding SRS-induced pain relief, we found a significant GMV increase in the left superior frontal gyrus associated with greater degree of pain relief (P = .024) and a trend toward an increase in GMV in the left dorsolateral prefrontal cortex (P = .097). CONCLUSIONS: In this pilot study, we observed significant increases in GMV in the left superior frontal gyrus with SRS-induced improvements in pain and a trend toward an increase in GMV in the dorsolateral prefrontal cortex. Future studies are indicated to validate these findings and determine whether SRS-induced decrease in distracting pain events and subsequent increases in GMV result in improved functionality, decreased dependence on "top-down" control, and improved cognitive/executive balance with amelioration of pain events.

Long-Term Patient-Reported Outcomes of Stereotactic Radiosurgery for Trigeminal Neuralgia.

BACKGROUND: We aimed to evaluate patient-reported outcomes (PROs) of stereotactic radiosurgery (SRS) for TN in terms of treatment efficacy and toxicity. METHODS: We retrospectively analyzed patients who underwent Gamma Knife SRS for idiopathic or classic TN between January 2013 and February 2022. Questionnaires regarding pain relief, treatment toxicity, and post-SRS treatment were sent between late 2022 and early 2023, and the responses received were analyzed. The Faces Pain Scale (FPS, 0: best, 5: worst) was used for quantitative evaluation. RESULTS: Responses were received from 51 patients (76%). The mean pre-SRS FPS score was 4.1 (standard deviation (SD) 1.1). Forty-three patients (83%) reported initial pain relief and the best post-SRS FPS score was 1.1 (SD 1.5) (P < 0.001). At a median follow-up of 50 months, the FPS score was still 1.1 (SD 1.6) (P < 0.001). Analysis of factors contributing to durable pain relief showed neurovascular compression to be associated with FPS score improvement (Odds ratio 5.7, 95% CI 1.1-29.7, P = 0.038). Facial dysesthesia had a mean pre-SRS FPS score of 1.7 (SD 2.0) and a mean score of 1.4 (SD 1.7) at the last follow-up (P = 0.32). Eight patients (15%) received post-SRS interventions and 21 (40%) no longer required pharmacotherapy without post-SRS intervention. Forty-four patients (85%) reported being satisfied with SRS. CONCLUSIONS: We analyzed PROs of SRS for TN using the FPS and showed SRS to be a safe and effective treatment modality achieving long lasting pain relief.

The relevance of biologically effective dose for pain relief and sensory dysfunction after Gamma Knife radiosurgery for trigeminal neuralgia: an 871-patient multicenter study.

OBJECTIVE: Recent studies have suggested that biologically effective dose (BED) is an important correlate of pain relief and sensory dysfunction after Gamma Knife radiosurgery (GKRS) for trigeminal neuralgia (TN). The goal of this study was to determine if BED is superior to prescription dose in predicting outcomes in TN patients undergoing GKRS as a first procedure. METHODS: This was a retrospective study of 871 patients with type 1 TN from 13 GKRS centers. Patient demographics, pain characteristics, treatment parameters, and outcomes were reviewed. BED was compared with prescription dose and other dosimetric factors for their predictive value. RESULTS: The median age of the patients was 68 years, and 60% were female. Nearly 70% of patients experienced pain in the V2 and/or V3 dermatomes, predominantly on the right side (60%). Most patients had modified BNI Pain Intensity Scale grade IV or V pain (89.2%) and were taking 1 or 2 pain medications (74.1%). The median prescription dose was 80 Gy (range 62.5-95 Gy). The proximal trigeminal nerve was targeted in 77.9% of cases, and the median follow-up was 21 months (range 6-156 months). Initial pain relief (modified BNI Pain Intensity Scale grades I-IIIa) was noted in 81.8% of evaluable patients at a median of 30 days. Of 709 patients who achieved initial pain relief, 42.3% experienced at least one pain recurrence after GKRS at a median of 44 months, with 49.0% of these patients undergoing a second procedure. New-onset facial numbness occurred in 25.3% of patients after a median of 8 months. Age ≥ 63 years was associated with a higher probability of both initial pain relief and maintaining pain relief. A distal target location was associated with a higher probability of initial and long-term pain relief, but also a higher incidence of sensory dysfunction. BED ≥ 2100 Gy2.47 was predictive of pain relief at 30 days and 1 year for the distal target, whereas physical dose ≥ 85 Gy was significant for the proximal target, but the restricted range of BED values in this subgroup could be a confounding factor. A maximum brainstem point dose ≥ 29.5 Gy was associated with a higher probability of bothersome facial numbness. CONCLUSIONS: BED and physical dose were both predictive of pain relief and could be used as treatment planning goals for distal and proximal targets, respectively, while considering maximum brainstem point dose < 29.5 Gy as a potential constraint for bothersome numbness.

[Stereotactic Radiosurgery for Trigeminal Neuralgia].

Stereotactic radiosurgery(SRS)performed with Gamma Knife or CyberKnife has been reported to be effective in treating trigeminal neuralgia(TN). Microvascular decompression is the first choice of treatment for patients with trigeminal neuralgia who are difficult to treat with drugs because of its high efficacy, with a pain relief rate of 70%-80% after 5 years. The pain relief rate of TN treated with SRS is approximately 50%-60% after 5 years, which is less than that of MVD. SRS is also inferior to surgery, causing more frequent sensory disturbances in the trigeminal nerve area(6%-20%). However, the serious complications, severe morbidity and mortality, associated with SRS are quite rare. SRS is an extremely minimally invasive treatment that does not require general anesthesia and can be used to treat TN with short-term hospitalization or outpatient visits.

Repeat Gamma Knife radiosurgery for recurrent trigeminal neuralgia in patients with multiple sclerosis: a single-center retrospective study.

PURPOSE: Gamma Knife radiosurgery (GKRS) has emerged as an effective treatment option for trigeminal neuralgia (TN) in patients with multiple sclerosis (MS). To date, the outcomes of repeat GKRS for patients with TN and MS with recurrent pain have been investigated in a few patients. This study aims to report the outcomes and predictive factors of pain reduction for MS patients undergoing repeat GKRS for recurrent TN. METHODS: Eighteen patients with MS underwent repeat GKRS for recurrent TN. A retrospective chart review and telephone interviews were conducted to determine background medical history, dosimetric data, and outcomes of the procedure. Facial pain and sensory function were evaluated using the Barrow Neurological Institute (BNI) scales. RESULTS: Fifteen patients achieved a BNI pain score of IIIa or better, indicating pain reduction, within a median period of 21 days after repeat GKRS. The maximum dose for repeat GKRS ranged from 70 to 85 Gy. Pain recurred in 5 patients after a median period of 12 months after GKRS. Percentages of patients with pain reduction at 1, 2, 3, 5, and 7 years were 60%, 60%, 50%, 50%, and 50%, respectively. Older age at repeat GKRS predicted sustained pain reduction (P = 0.01). Seven patients developed facial sensory disturbances, which were bothersome in two patients. CONCLUSIONS: Repeat GKRS may be used as an effective treatment modality for prolonging the duration of pain reduction time in patients with MS and TN. After repeat GKRS, facial sensory disturbances are common; however, they are often not bothersome.

Gamma knife radiosurgery for trigeminal neuralgia: first case series from Latin America / Radiocirurgia por gamma knife para tratamento da neuralgia do trigêmeo: primeira série de casos na América Latina

ABSTRACT Gamma Knife® radiosurgery (GKRS) for trigeminal neuralgia is an effective treatment with at least a 50% reduction of pain in 75-95% of patients. Objective: To present the first series of patients treated for trigeminal neuralgia using GKRS in Latin America. Methods: Retrospective analysis. Analysis consisted of time to improvement of symptoms, best Barrow Neurological Institute scale (BNI) score after procedure, time without pain, time to recurrence and post-procedural hypoesthesia. Results: Nineteen cases of classical trigeminal neuralgia were analyzed and three cases of symptomatic trigeminal neuralgia were described. Mean time from symptom onset to radiosurgery was 99.6 months, and 78.9% of patients had undergone invasive procedures before treatment. Patients were followed for a mean of 21.7 months. BNI I was achieved in 36.8%, IIIa in 21.1%, IIIb in 21.1%, IV in 5.3% and V in 15.7%. New hypoesthesia developed in 12.1% patients, which was associated with achieving BNI I after the procedure (p < 0.05). Time from diagnosis to GKRS was higher in patients who failed to achieve BNI I (143 vs. 76 months). The distance from the root entry zone in patients who achieved BNI I was greater than patients who did not (1.94 vs. 1.14 mm). Mean distance from the root entry zone in patients with new hypoesthesia was 2.85 mm vs. 1.06 mm (p = 0.06). Conclusion: Clinical response to GKRS is related to the time between diagnosis and procedure, thus its indication should be considered early in the management of these patients.

RESUMO A radiocirurgia por Gamma Knife (GKRS) para neuralgia do trigêmeo é um tratamento comprovado, com redução de pelo menos 50% da dor em 75-95% dos casos. Objetivo: Apresentar a primeira série de pacientes tratados por neuralgia do trigêmeo com GKRS na America Latina. Métodos: Análise retrospectiva. A análise consistiu no tempo até melhora do sintoma, melhor escala do Barrow Neurological Institute (BNI) depois do procedimento, tempo sem dor, tempo até recorrência e hipoestesia pós-procedimento. Resultados: Dezenove casos de neuralgia do trigêmeo clássica foram analisados e três casos de neuralgia do trigêmeo sintomática foram descritos. Tempo médio entre começo dos sintomas e GKRS foi de 99,6 meses e 78,9% dos pacientes já tinham sido submetidos a procedimento invasivo prévio. O tempo de acompanhamento médio foi de 21,7 meses. BNI I foi conseguido em 36,8%, IIIa em 21,1%, IIIb em 21,1%, IV em 5,3% e V em 15,7%. Nova hipoestesia apareceu em 12,1% dos casos, o que foi associado a conseguir BNI I pós-procedimento (p < 0,05). Tempo desde o diagnóstico até GKRS foi maior em pacientes que não conseguiram BNI I (143 vs. 76 meses). Distância da zona de entrada do nervo em pacientes que conseguiram BNI I foi maior (1,94 vs. 1,14mm). Distância do zona de entrada do nervo em pacientes com nova hipoestesia foi de 2,85mm vs. 1,06mm (p = 0,06) Conclusão: A resposta à GKRS está relacionada ao tempo entre diagnóstico e procedimento, pelo que a indicação de GKRS deve ser considerada cedo no tratamento desses pacientes.

Laserterapia en la neuralgia trigeminal: informe preliminar / Lasertherapy in trigeminal neuralgia: preliminary report

Se presenta un estudio en 15 pacientes con diagnóstico de neuralgia trigeminal, que se organizaron en 3 grupos, según el tratamiento recibido: grupo A: tratamiento con fármacos; grupo B: tratamiento con radiaciones láser HeNe; grupo C: combinación de terapia láser HeNe y fármacos. Se compararon los resultados obtenidos en cada grupo estudiado y se observó la rapidez y efectividad de la radiación láser helioneón en la disminución de la crisis dolorosa, fundamentalmente cuando se combina con tratamiento de fármacos.