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

Stereotactic radiosurgery for tumor-related trigeminal neuralgia: a systematic review and meta-analysis

BACKGROUND

Tumor-related trigeminal neuralgia (TRTN) accounts for approximately 6% of all facial pain syndromes. Conventional medical treatments have short-term pain relief effects in TRTN cases; however, they are correlated with substantial failure rates of 63-100%. Microsurgical resection (MS) and stereotactic radiosurgery (SRS) are the two primary therapeutic options for the management of TRTNs. This systematic review and meta-analysis evaluated the pain-related outcomes and complications of SRS in TRTNs.

METHODS

A systematic literature search was conducted on February 24, 2025, comparing PubMed, Embase, Scopus, and Web of Science. Studies reporting pain-related outcomes and adverse radiation effects (ARE) for SRS in TRTNs were included.

RESULTS

Nineteen studies with 454 patients were included. Meningioma (67.7%, 304/449) was the most common tumor, followed by vestibular schwannoma (VS) (18.3%, 82/449) and trigeminal schwannoma (8.2%, 37/449). Our meta-analysis demonstrated that SRS is associated with a pooled complete pain-free rate of 38% (95% CI: 27-50%), an adequate pain relief rate of 73% (95% CI: 63-83%), and an ARE rate of 14% (95% CI: 7-22%). In those where the underlying etiology was pertoclival meningiomas, SRS resulted in a pooled complete pain-free rate of 30% (95%CI: 5-64%), an adequate complete pain relief rate of 64% (95%CI: 33-90%), and an ARE rate of 13% (95%CI: 0-48%).

CONCLUSION

SRS is associated with favorable pain-related outcomes and low ARE rates in patients with TRTN. Both tumor-only related and dual-targeted approaches are associated with comparable outcomes.

Gamma knife radiosurgery for benign tumor-related trigeminal neuralgia: a single-institution retrospective study

BACKGROUND

Gamma knife stereotactic radiosurgery (GKRS) is recognized as an effective and safe alternative treatment for skull base tumors and trigeminal neuralgia. This study aims to evaluate the efficacy of targeting both tumor and trigeminal nerve in a single procedure for patients with benign tumor-related trigeminal neuralgia.

METHODS

A retrospective study was conducted on 44 patients with benign tumor-related trigeminal neuralgia who underwent GKRS targeting both tumor and trigeminal nerve in a single procedure between December 2016 and December 2022. The cohort included 30 meningiomas, 9 vestibular schwannomas, and 5 trigeminal schwannomas. The median tumor volume was 3.62 mL (range: 0.14-20.74 mL). The median radiation dose was 12-13.4 Gy for the tumors and 88.9 Gy (range: 85-90 Gy) at the 100% isodose line for the trigeminal nerve. The facial pain before and after GKRS was assessed using the Barrow Neurological Institute (BNI) pain intensity scale.

RESULTS

Following GKRS, 38 patients (86.4%) experienced significant pain improvement, with a median latency period of 2 months (range: 0.3-12 months). Sixteen patients (36.4%) experienced a relapse at a median time of 6 months (range: 1-30 months) post-GKRS. After a median follow-up time of 31.9 months (12.1-77.3 months), 22 patients (50.0%) continued to experience durable pain relief. Fourteen patients (31.8%) developed GKRS-related complications, most of which fully resolved, except in 3 patients (6.8%) who experienced permanent facial hypoesthesia. Tumor control rate was 86.2%.

CONCLUSIONS

GKRS targeting both the tumor and trigeminal nerve in a single session demonstrated favorable outcomes in terms of pain relief and tumor control in patients with benign tumor-related trigeminal neuralgia.

Trigeminal Neuralgia Secondary to Meningiomas and Vestibular Schwannoma Is Improved after Stereotactic Radiosurgery: A Systematic Review and Meta-Analysis

INTRODUCTION

Trigeminal neuralgia (TN) secondary to tumors is encountered in up to 6% of patients with facial pain syndromes and is considered to be associated with tumors affecting the trigeminal nerve pathways. The most frequent are meningiomas and vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has emerged as a valuable treatment, with heterogeneity of clinical results. We sought to review the medical literature on TN treated with SRS for meningiomas and VS and investigate the rates of improvement of TN symptoms.

METHODS

We reviewed articles published between January 1990 and December 2019 in PubMed. Pain relief after SRS, the maintenance of pain relief, and TN recurrence and complications were evaluated with separate meta-analyses, taking into account the data on individual patients.

RESULTS

Pain relief after SRS was reported as Barrow Neurological Institute (BNI) pain intensity scores of BNI I in 50.5% (range 36-65.1%) of patients and BNI I-IIIb in 83.8% (range 77.8-89.8%). There was no significant difference in series discussing outcomes for tumor targeting versus tumor and nerve targeting. Recurrences were described in 34.7% (range 21.7-47.6; tumor targeting). Maintenance of BNI I was reported in 36.4% (range 20.1-52.7) and BNI I-IIIb in 41.2% (range 29.8-52.7; tumor targeting series). When both the nerve and the tumor were targeted, only 1 series reported 86.7% with BNI I-IIIb at last follow-up. Complications were encountered in 12.6% (range 6.3-18.8; tumor targeting series) of patients; however, they were much higher, as high as 26.7%, in the only study reporting them after targeting both the nerve and the tumor. The most common complication was facial numbness.

CONCLUSION

SRS for TNB secondary to benign tumors, such as meningiomas and VS, is associated with favorable clinical course, but less favorable than in idiopathic TN. There was, however, heterogeneity among reports and targeting approaches. Although targeting both the nerve and the tumor seemed to achieve better long-term results, the rate of complications was much higher and the number of patients treated was limited. Future clinical studies should focus on the standard reporting of clinical outcomes and randomization of targeting methods.

Radiosurgery vs. microsurgery for newly diagnosed, small petroclival meningiomas with trigeminal neuralgia

Trigeminal neuralgia (TN) is an excruciating pain that can occur with petroclival meningiomas (PCMs). Gamma knife radiosurgery (GKRS) is an appealing option for small PCMs, but the role of microsurgery (MS) compared to GKRS is not well defined for small PCMs with regard to TN relief. From January 2009 to September 2019, 70 consecutive patients were treated by GKRS or MS for newly diagnosed, small (< 3.5 cm) PCMs with TN. GKRS or MS were performed for 35 patients each. The surgical outcome and TN control according to Barrow Neurological Institute (BNI) score were retrospectively analyzed and compared between GKRS and MS. The predominant origin of PCMs was upper clival (49%) with trigeminal nerve compression at the medial dorsal root entry zone. Tumor control rates were equally 94% with GKRS or MS for a mean tumor size and volume of 2.3 cm and 5.3 cm³, respectively. The preoperative BNI scores were mostly II (40%) and IV (37%) with GKRS and MS, respectively. TN relief without medications (BNI scores I and II) was achieved in 13 of 35 patients (37%) with GKRS and 32 of 35 patients (91%) with MS during a mean follow-up of 50.5 months. The most common complications after GKRS and MS were dysesthesia (23%) and diplopia (9%), respectively. MS could be more effective than GKRS in providing prompt, medication-free pain relief from TN for small PCMs. The risks of MS have to be considered carefully in experienced hands, especially for small PCMs.

Gamma knife radiosurgery for trigeminal neuralgia: first case series from Latin America

INTRODUCTION

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.

Stereotactic radiosurgery for trigeminal pain secondary to recurrent malignant skull base tumors

OBJECTIVE

The objective of this study was to assess outcomes after Gamma Knife radiosurgery (GKRS) re-irradiation for palliation of patients with trigeminal pain secondary to recurrent malignant skull base tumors.

METHODS

From 2009 to 2016, 26 patients who had previously undergone radiation treatment to the head and neck received GKRS for palliation of trigeminal neuropathic pain secondary to recurrence of malignant skull base tumors. Twenty-two patients received single-fraction GKRS to a median dose of 17 Gy (range 15-20 Gy) prescribed to the 50% isodose line (range 43%-55%). Four patients received fractionated Gamma Knife Extend therapy to a median dose of 24 Gy in 3 fractions (range 21-27 Gy) prescribed to the 50% isodose line (range 45%-50%). Those with at least a 3-month follow-up were assessed for symptom palliation. Self-reported pain was evaluated by the numeric rating scale (NRS) and MD Anderson Symptom Inventory-Head and Neck (MDASI-HN) pain score. Frequency of as-needed (PRN) analgesic use and opioid requirement were also assessed. Baseline opioid dose was reported as a fentanyl-equivalent dose (FED) and PRN for breakthrough pain use as oral morphine-equivalent dose (OMED). The chi-square and Student t-tests were used to determine differences before and after GKRS.

RESULTS

Seven patients (29%) were excluded due to local disease progression. Two experienced progression at the first follow-up, and 5 had local recurrence from disease outside the GKRS volume. Nineteen patients were assessed for symptom palliation with a median follow-up duration of 10.4 months (range 3.0-34.4 months). At 3 months after GKRS, the NRS scores (n = 19) decreased from 4.65 ± 3.45 to 1.47 ± 2.11 (p < 0.001); MDASI-HN pain scores (n = 13) decreased from 5.02 ± 1.68 to 2.02 ± 1.54 (p < 0.01); scheduled FED (n = 19) decreased from 62.4 ± 102.1 to 27.9 ± 45.5 mcg/hr (p < 0.01); PRN OMED (n = 19) decreased from 43.9 ± 77.5 to 10.9 ± 20.8 mg/day (p = 0.02); and frequency of any PRN analgesic use (n = 19) decreased from 0.49 ± 0.55 to 1.33 ± 0.90 per day (p = 0.08). At 6 months after GKRS, 9 (56%) of 16 patients reported being pain free (NRS score 0), with 6 (67%) of the 9 being both pain free and not requiring analgesic medications. One patient treated early in our experience developed a temporary increase in trigeminal pain 3-4 days after GKRS requiring hospitalization. All subsequently treated patients were given a single dose of intravenous steroids immediately after GKRS followed by a 2-3-week oral steroid taper. No further cases of increased or new pain after treatment were observed after this intervention.

CONCLUSIONS

GKRS for palliation of trigeminal pain secondary to recurrent malignant skull base tumors demonstrated a significant decrease in patient-reported pain and opioid requirement. Additional patients and a longer follow-up duration are needed to assess durability of symptom relief and local control.

Trigeminal neuropathy in vestibular schwannoma: a treatment algorithm to avoid long-term morbidity

BACKGROUND

Trigeminal neuropathy (TGN) can occur as a presenting feature of vestibular schwannoma (VS) or as an adverse effect of radiosurgery. This study was designed to evaluate a treatment algorithm for presenting symptoms of TGN in patients with VS, and a new radiosurgery dosimetric tolerance to avoid TGN after treatment. Outcome was measured after microsurgery (MS), stereotactic radiosurgery (SRS), hypofractionated stereotactic radiotherapy (HSRT), and fractionated radiotherapy (FRT).

METHODS

A prospectively held VS database was retrospectively analysed from 2011 to 2016 at a tertiary university hospital. All patients who underwent MS from 2011 and all patients who underwent radiotherapy (SRS, HSRT, FRT) from 2015 were studied. Patients on surveillance and neurofibromatosis type 2 patients were not included. Patient demographic data, tumour characteristics, presenting symptoms, and post-treatment outcomes were analysed.

RESULTS

Eighty-eight patients were included in the study (43 microsurgery, 45 radiotherapy). Twenty-seven (31%) patients presented with TGN symptoms. The median age of patients included was 56.5 (range 6-72 years), with a median follow-up for MS and SRS of 38 and 20 months, respectively (range 10-80 months). All 27 patients with TGN were offered MS as per protocol. Three patients declined, or were not fit for surgery, and received FRT. Complete resolution of TGN symptoms was achieved in all 24 patients who underwent MS and 33% (1/3) of patients with FRT. Eleven patients experienced transient post-operative complications (pseudomeningocele (6), meningitis (3), venous sinus thrombosis, cerebellar haemorrhagic contusion, and posterior fossa haematoma). Of the 45 patients in the radiotherapy cohort, 36 were suitable for SRS, of which 30 patients who met the dose-volume constraints for trigeminal nerve underwent single-fraction SRS and 6 patients who did not meet the constraints received HSRT. Nine patients (20%) received FRT including three patients with pre-treatment TGN. None of the patients developed new TGN symptoms following SRS or HSRT.

CONCLUSIONS

Our algorithm to select the optimal treatment modality appears to achieve comparable or better long-term outcome. Microsurgical resection in our cohort resulted in complete resolution of symptoms in all patients. None of our SRS- or HSRT-treated patients developed TGN during the follow-up period. The adherence to strict trigeminal nerve dose-volume constraints for SRS remains critical to minimise TGN post treatment. Fractionated radiotherapy is an alternative for patients who refuse surgery or those who are unfit for surgery.

Trigeminal neuralgia and neuropathy in large sporadic vestibular schwannomas

OBJECTIVE

The aim of this study was to evaluate the incidence, presentation, and treatment outcomes of trigeminal nerve–mediated symptoms secondary to large vestibular schwannomas (VSs) with trigeminal nerve contact. Specifically, the symptomatic results of pain, paresthesias, and numbness after microsurgical resection or stereotactic radiosurgery (SRS) were examined.

METHODS

The authors conducted a retrospective review of a database for concomitant diagnosis of trigeminal neuralgia (TN) or trigeminal neuropathy and VS between 1994 and 2014 at a tertiary academic center. All patients with VS with TN or neuropathy were included, with the exception of those patients with neurofibromatosis Type 2 and patients who elected observation. Patient demographic data, symptom evolution, and treatment outcomes were collected. Population data were summarized, and outcome comparisons between microsurgery and SRS were analyzed at last follow-up.

RESULTS

Sixty (2.2%) of 2771 total patients who had large VSs and either TN or neuropathy symptoms met inclusion criteria. The average age of trigeminal symptom onset was 53.6 years (range 24–79 years), the average age at VS diagnosis was 54.4 years (range 25–79 years), and the average follow-up for the microsurgery and SRS groups was 30 and 59 months, respectively (range 3–132 months). Of these patients, 50 (83%) had facial numbness, 16 (27%) had TN pain, and 13 (22%) had paresthesias (i.e., burning or tingling). Subsequently, 50 (83%) patients underwent resection and 10 (17%) patients received SRS.

Treatment of VS with SRS did not improve trigeminal symptoms in any patient. This included 2 subjects with unimproved facial numbness and 4 patients with worsened numbness. Similarly, SRS worsened TN pain and paresthesias in 5 patients and failed to improve pain in 2 additional patients. The Barrow Neurological Institute neuralgia and hypesthesia scale scores were significantly worse for patients undergoing SRS compared with microsurgery.

Resection alleviated facial numbness in 22 (50%) patients, paresthesias in 5 (42%) patients, and TN in 7 (70%) patients. In several patients, surgery was not successful in relieving facial numbness, which failed to improve in 17 (39%) cases and became worse in 5 (11%) cases. Also, surgery did not change the intensity of facial paresthesias or neuralgia in 6 (50%) and 3 (25%) patients, respectively. Microsurgery exacerbated facial paresthesias in 1 (8%) patient but, notably, did not aggravate TN in any patient.

CONCLUSIONS

Overall, resection of large VSs provided improved outcomes for patients with concomitant TN, facial paresthesia, and numbness compared with SRS. However, caution should be used when counseling surgical candidates because a number of patients did not experience improvement. This was especially true in patients with preoperative facial numbness and paresthesias, who frequently reported that these symptoms were unchanged following surgery.

Radiosurgery for Secondary Trigeminal Neuralgia: Revisiting the Treatment Paradigm

BACKGROUND

The mechanisms by which surgery and radiation elicit pain relief in trigeminal neuralgia (TN) secondary to mass lesions vary widely. We aimed to evaluate the outcomes of radiation to the nerve rather than to the lesion in the treatment of secondary TN.

METHODS

We retrospectively reviewed all patients who underwent radiation at the University of California, Los Angeles for TN secondary to tumors. The Barrow Neurological Institute (BNI) pain score was used to evaluate pain outcomes.

RESULTS

Twelve patients were identified; 4 were male and 8 were female. Their mean age at treatment was 59.8 years (range, 47.7-84.7 years). Tumor pathologies included meningioma (n = 8), squamous cell carcinoma (n = 2), vestibular schwannoma (n = 1), and hemangiopericytoma (n = 1). No patient suffered from multiple sclerosis. Ten patients underwent initial radiation targeting their tumors-radiosurgery in 3 and fractionated radiation therapy in 7 others. Only 6 among these 10 experienced at least partial relief, which lasted a mean 6 months. Radiosurgery targeting the trigeminal nerve was eventually performed. Overall, 10 of 12 (83.3%) patients experienced good initial pain relief, complete in 6 (50%) patients. Pain recurred in 6 (60%) patients, at a mean 41 months after radiosurgery to the trigeminal nerve. Three patients experienced facial sensory dysfunction postprocedurally at a mean follow-up duration of 57 months.

CONCLUSION

In contrast to tumor radiation, radiosurgery to the trigeminal nerve root resulted in reasonable and longer pain reduction, on par with the literature regarding surgical resection, with low risk of additional complications.

Gamma Knife surgery for tumor-related trigeminal neuralgia: targeting both the tumor and the trigeminal root exit zone in a single session

OBJECTIVE

Gamma Knife surgery (GKS) represents an alternative treatment for patients with tumor-related trigeminal neuralgia (TRTN). However, in previous studies, the primary GKS target was limited to mass lesions. The authors evaluated whether GKS could target both the tumor and the trigeminal root exit zone (REZ) in a single session while providing durable pain relief and minimizing radiation dose–related complications for TRTN patients.

METHODS

The authors' institutional review board approved the retrospective analysis of data from 15 consecutive patients (6 men and 9 women, median age 67 years, range 45–79 years) with TRTN who had undergone GKS. In all cases, the radiation was delivered in a single session targeting both the tumor and trigeminal REZ. The authors assessed the clinical outcomes, including the extent of pain relief, durability of the treatment response, and complications. Radiation doses to organs at risk (OARs), including the brainstem and the cranial nerve VII–VIII complex, were analyzed as doses received by 2% or 50% of the tissue volume and the tissue volume covered by a dose of 12 Gy (V12Gy).

RESULTS

The median length of clinical follow-up was 38 months (range 12–78 months). Pain relief with GKS was initially achieved in 14 patients (93.3%) and at the last follow-up in 13 patients (86.7%). The actuarial recurrence-free survival rates were 93%, 83%, and 69% at 1, 3, and 5 years after GKS, respectively. Persistent facial numbness was observed in 3 patients (20.0%). There were no complications such as facial weakness, altered taste function, hearing impairment, and balance difficulties indicating impaired function of the cranial nerve VII–VIII complex. The V12Gy in the brainstem was less than or equal to 0.24 cm3 in all patients. There were no significant differences in any OAR values in the brainstem between patients with and without facial numbness after GKS.

CONCLUSIONS

The strategy of performing GKS for both tumor and trigeminal REZ in a single session is a safe and effective radiosurgical approach that achieves durable pain control for TRTN patients.

Gamma knife radiosurgery to the trigeminal ganglion for treatment of trigeminal neuralgia secondary to vertebrobasilar ectasia

Background:

We report the result obtained using Gamma knife stereotactic radiosurgery on the trigeminal ganglion (TG) in a patient with trigeminal neuralgia (TN) secondary to vertebrobasilar ectasia (VBE).

Case Description:

Retrospective review of medical records corresponding to one patient with VBE-related trigeminal pain treated with radiosurgery. Because of the impossibility of visualization of the entry zone or the path of trigeminal nerve through the pontine cistern, we proceeded with stereotactic radiosurgery directed to the TG. The maximum radiation dose was 86 Gy with a 8-mm and a 4-mm collimator. The follow-up period was 24 months. The pain disappeared in 15 days, passing from Barrow Neurological Institute (BNI) grade V to BNI grade IIIa in 4 months and then to grade I. The patient did not experience noticeable subjective facial numbness.

Conclusions:

This experience showed that Gamma knife radiosurgery was effective in the management of VBE-related trigeminal pain, using the TG as radiosurgical target.

Gamma Knife® radiosurgery for trigeminal neuralgia

Trigeminal neuralgia is characterized by a temporary paroxysmal lancinating facial pain in the trigeminal nerve distribution. The prevalence is four to five per 100,000. Local pressure on nerve fibers from vascular loops results in painful afferent discharge from an injured segment of the fifth cranial nerve. Microvascular decompression addresses the underlying pathophysiology of the disease, making this treatment the gold standard for medically refractory trigeminal neuralgia. In patients who cannot tolerate a surgical procedure, those in whom a vascular etiology cannot be identified, or those unwilling to undergo an open surgery, stereotactic radiosurgery is an appropriate alternative. The majority of patients with typical facial pain will achieve relief following radiosurgical treatment. Long-term follow-up for recurrence as well as for radiation-induced complications is required in all patients undergoing stereotactic radiosurgery for trigeminal neuralgia.

Stereotactic radiosurgery for trigeminal pain secondary to benign skull base tumors

OBJECTIVE

To assess the outcome of stereotactic radiosurgery (SRS) for patients with benign skull base tumors and trigeminal-related facial pain.

METHODS

We undertook a retrospective review of 31 consecutive patients (25 women, 6 men) with benign skull base tumors and trigeminal pain who underwent SRS between 1991 and 2008. The tumors included 17 posterior fossa meningiomas, 9 cavernous sinus meningiomas, and 5 trigeminal schwannomas. The median patient age was 62 years (range, 17-81 years). In all cases the tumor was the primary target for SRS. The median follow-up after SRS was 50 months (range, 12-184 months).

RESULTS

The actuarial tumor control rate after SRS was 95% at both 3 years and 5 years. Eighteen patients (58%) initially achieved complete resolution of trigeminal pain. Higher maximum dose was associated with initial complete pain resolution on a multivariate analysis. However, 7 patients had recurrent pain during follow-up. At last follow-up, only 7 patients (23%) remained pain-free off medications. Further treatment in addition to medical therapy was required for 6 patients (19%).

CONCLUSION

Although SRS offers excellent radiographic tumor control for benign skull base tumors, durable relief of tumor-related trigeminal pain without medication was noted in only one-fourth of patients at last follow-up.

Repeat gamma knife radiosurgery for trigeminal neuralgia

PURPOSE

Repeat gamma knife stereotactic radiosurgery (GKRS) for recurrent or persistent trigeminal neuralgia induces an additional response but at the expense of an increased incidence of facial numbness. The present series summarized the results of a repeat treatment series at Wake Forest University Baptist Medical Center, including a multivariate analysis of the data to identify the prognostic factors for treatment success and toxicity.

METHODS AND MATERIALS

Between January 1999 and December 2007, 37 patients underwent a second GKRS application because of treatment failure after a first GKRS treatment. The mean initial dose in the series was 87.3 Gy (range, 80-90). The mean retreatment dose was 84.4 Gy (range, 60-90). The dosimetric variables recorded included the dorsal root entry zone dose, pons surface dose, and dose to the distal nerve.

RESULTS

Of the 37 patients, 81% achieved a >50% pain relief response to repeat GKRS, and 57% experienced some form of trigeminal dysfunction after repeat GKRS. Two patients (5%) experienced clinically significant toxicity: one with bothersome numbness and one with corneal dryness requiring tarsorraphy. A dorsal root entry zone dose at repeat treatment of >26.6 Gy predicted for treatment success (61% vs. 32%, p = .0716). A cumulative dorsal root entry zone dose of >84.3 Gy (72% vs. 44%, p = .091) and a cumulative pons surface dose of >108.5 Gy (78% vs. 44%, p = .018) predicted for post-GKRS numbness. The presence of any post-GKRS numbness predicted for a >50% decrease in pain intensity (100% vs. 60%, p = .0015).

CONCLUSION

Repeat GKRS is a viable treatment option for recurrent trigeminal neuralgia, although the patient assumes a greater risk of nerve dysfunction to achieve maximal pain relief.

CyberKnife radiosurgery for trigeminal neuralgia: unanticipated iatrogenic effect following successful treatment

This case report of 74-year-old man with trigeminal neuralgia is presented to underscore the importance of evaluating the entire treatment plan, especially when delivering large doses where even a low percentage of the prescription dose can contribute a substantial dose to an unintended target. The patient was treated using the CyberKnife stereotactic radiosurgery system utilizing a nonisocentric beam treatment plan with a 5-mm fixed collimator generating 111 beams to deliver 6000 cGy to the 79% isodose line with a maximum dose of 7594 cGy to the target. Two weeks after treatment the patient's trigeminal neuralgia symptoms resolved; however, the patient developed oral mucositis due to the treatment. This case report reviews the cause of mucositis and makes recommendations on how to prevent unintended targets from receiving treatment.

Predictive Variables for the Successful Treatment of Trigeminal Neuralgia With Gamma Knife Radiosurgery

Background:

Gamma Knife radiosurgery (GKRS) has been reported to be an effective modality to treat trigeminal neuralgia.

Objective:

To determine predictive factors for the successful treatment of trigeminal neuralgia with GKRS.

Methods:

Between 1999 and 2008, 777 GKRS procedures for patients with trigeminal neuralgia were performed at our institution. Evaluable follow-up data were obtained for 448 patients. Median follow-up time was 20.9 months (range, 3–86 months). The mean maximum prescribed dose was 88 Gy (range, 80–97 Gy). Dosimetric variables recorded included dorsal root entry zone dose, pons maximum dose, dose to the petrous dural ridge, and cisternal nerve length.

Results:

By 3 months after GKRS, 86% of patients achieved Barrow Neurologic Institute I to III pain scores, with 43% of patients achieving a Barrow Neurologic Institute I pain score. Twenty-six percent of patients reported posttreatment facial numbness; 28% of patients reported a post-GKRS procedure for relapsed pain, and median time to next procedure was 4.4 years. Multivariate analysis revealed that the development of postsurgical numbness (odds ratio [OR], 2.76; P = .006) was the dominant factor predictive of efficacy. Longer cisternal nerve length (OR, 0.85; P = .005), prior radiofrequency ablation (OR, 0.35; P = .028), and diabetes mellitus (OR, 0.38; P = .013) predicted decreased efficacy. The mean dose delivered to the dorsal root entry zone dose in patients who developed facial numbness (57.6 Gy) was more than the mean dose (47.3 Gy) given to patients who did not develop numbness (P = .02).

Conclusion:

The development of post-GKRS facial numbness is a dominant factor that predicts for efficacy of GKRS. History of diabetes mellitus or previous radio-frequency ablation may portend worsened outcome.

Outcome predictors after gamma knife radiosurgery for recurrent trigeminal neuralgia

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.

Frameless image-guided radiosurgery for initial treatment of typical trigeminal neuralgia

OBJECTIVE

To review retrospectively initial experience at a single institution using frameless image-guided radiosurgery (IGRS) for trigeminal neuralgia employing the Novalis linear accelerator (LINAC) with ExacTrac robotic patient positioning device.

METHODS

Over an 18-month period, 44 patients (27 women and 17 men; median age 65 years) were treated with frameless IGRS for typical trigeminal neuralgia (14 cases involved left-sided pain and 30 cases involved right-sided pain), responsive to anticonvulsant medications, with Barrow Neurological Institute Pain Scale (BNI-PS) scores of 4 or 5. All cases were initial radiosurgery treatments with an isocenter dose of 90 Gy delivered via a 4-mm circular collimator forming a spheroid dose envelope. Intrafraction positioning data were collected for all patients. The median follow-up was 15 months.

RESULTS

Overall intrafraction positioning error was 0.49 mm ± 0.44. After treatment, 40 patients achieved a BNI-PS score of IIIb or better; 19 patients achieved a BNI-PS score of I. The median time to pain relief was 4 weeks. Overall, new hypoesthesia was seen in five patients. No other complications were seen.

CONCLUSIONS

Use of frameless IGRS methods for treatment of trigeminal neuralgia showed results similar to the authors' prior experience with frame-based treatment methods. IGRS using frameless methods is a suitable treatment method for patients with trigeminal neuralgia and may be applicable to other functional indications.

Gamma Knife stereotactic radiosurgery for idiopathic trigeminal neuralgia

OBJECT

Trigeminal neuralgia pain causes severe disability. Stereotactic radiosurgery is the least invasive surgical option for patients with trigeminal neuralgia. Since different medical and surgical options have different rates of pain relief and morbidity, it is important to evaluate longer-term outcomes.

METHODS

The authors retrospectively reviewed outcomes in 503 medically refractory patients with trigeminal neuralgia who underwent Gamma Knife surgery (GKS). The median patient age was 72 years (range 26-95 years). Prior surgery had failed in 205 patients (43%). The GKS typically was performed using MR imaging guidance, a single 4-mm isocenter, and a maximum dose of 80 Gy.

RESULTS

Patients were evaluated for up to 16 years after GKS; 107 patients had > 5 years of follow-up. Eighty-nine percent of patients achieved initial pain relief that was adequate or better, with or without medications (Barrow Neurological Institute [BNI] Scores I-IIIb). Significant pain relief (BNI Scores I-IIIa) was achieved in 73% at 1 year, 65% at 2 years, and 41% at 5 years. Including Score IIIb (pain adequately controlled with medication), a BNI score of I-IIIb was found in 80% at 1 year, 71% at 3 years, 46% at 5 years, and 30% at 10 years. A faster initial pain response including adequate and some pain relief was seen in patients with trigeminal neuralgia without additional symptoms, patients without prior surgery, and patients with a pain duration of < or = 3 years. One hundred ninety-three (43%) of 450 patients who achieved initial pain relief reported some recurrent pain 3-144 months after initial relief (median 50 months). Factors associated with earlier pain recurrence that failed to maintain adequate or some pain relief were trigeminal neuralgia with additional symptoms and > or = 3 prior failed surgical procedures. Fifty-three patients (10.5%) developed new or increased subjective facial paresthesias or numbness and 1 developed deafferentation pain; these symptoms resolved in 17 patients. Those who developed sensory loss had better long-term pain control (78% at 5 years).

CONCLUSIONS

Gamma Knife surgery proved to be safe and effective in the treatment of medically refractory trigeminal neuralgia and is of value for initial or recurrent pain management. Despite the goal of minimizing sensory loss with this procedure, some sensory loss may improve long-term outcomes. Pain relapse is amenable to additional GKS or another procedure.

Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM's it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.

Nonisocentric radiosurgical rhizotomy for trigeminal neuralgia

OBJECTIVE

Although stereotactic radiosurgery is an established procedure for treating trigeminal neuralgia (TN), the likelihood of a prompt and durable complete response is not assured. Moreover, the incidence of facial numbness remains a challenge. To address these limitations, a new, more anatomic radiosurgical procedure was developed that uses the CyberKnife (Accuray, Inc., Sunnyvale, CA) to lesion an elongated segment of the retrogasserian cisternal portion of the trigeminal sensory root. Because the initial experience with this approach resulted in an unacceptably high incidence of facial numbness, a gradual dose and volume de-escalation was performed over several years. In this single-institution prospective study, we evaluated clinical outcomes in a group of TN patients who underwent lesioning with seemingly optimized nonisocentric radiosurgical parameters.

METHODS

Forty-six patients with intractable idiopathic TN were treated between January 2005 and June 2007. Eligible patients were either poor surgical candidates or had failed previous microvascular decompression or destructive procedures. During a single radiosurgical session, a 6-mm segment of the affected nerve was treated with a mean marginal prescription dose of 58.3 Gy and a mean maximal dose of 73.5 Gy. Monthly neurosurgical follow-up was performed until the patient became pain-free. Longer-term follow-up was performed both in the clinic and over the telephone. Outcomes were graded as excellent (pain-free and off medication), good (>90% improvement while still on medication), fair (50-90% improvement), or poor (no change or worse). Facial numbness was assessed using the Barrow Neurological Institute Facial Numbness Scale score.

RESULTS

Symptoms disappeared completely in 39 patients (85%) after a mean latency of 5.2 weeks. In most of these patients, pain relief began within the first week. TN recurred in a single patient after a pain-free interval of 7 months; all symptoms abated after a second radiosurgical procedure. Four additional patients underwent a repeat rhizotomy after failing to respond adequately to the first operation. After a mean follow-up period of 14.7 months, patient-reported outcomes were excellent in 33 patients (72%), good in 11 patients (24%), and poor/no improvement in 2 patients (4%). Significant ipsilateral facial numbness (Grade III on the Barrow Neurological Institute Scale) was reported in 7 patients (15%).

CONCLUSION

Optimized nonisocentric CyberKnife parameters for TN treatment resulted in high rates of pain relief and a more acceptable incidence of facial numbness than reported previously. Longer follow-up periods will be required to establish whether or not the durability of symptom relief after lesioning an elongated segment of the trigeminal root is superior to isocentric radiosurgical rhizotomy.

Gamma Knife surgery for trigeminal pain caused by benign brain tumors

Object

The authors report the effects of Gamma Knife surgery (GKS) on benign tumor–related trigeminal pain in patients who underwent follow-up for a mean 57.8 months.

Methods

From 1999 to 2004, 21 patients with benign tumor–related trigeminal pain (12 meningiomas and 9 schwannomas) underwent GKS as a primary or repeated treatment. These patients harbored tumors within the radiosurgical target area. For meningiomas, the mean radiosurgical treatment volume was 8.2 ml (range 1.1–21 ml), and the mean radiosurgical tumor margin dose was 12.7 Gy (range 12–15 Gy); for schwannomas, the mean volume was 5.6 ml (range 2–9.2 ml), and the mean marginal dose was 13 Gy (range 11.5–16 Gy). Seven patients underwent retreatment for recurrent or persistent pain; the ipsilateral trigeminal nerve or ganglion was identified and a mean maximal dose of 60.7 Gy (range 40–70 Gy) was delivered to these targets. In 1 patient undergoing retreatment, the margin dose was 12 Gy. The mean age at the time of radiosurgery was 54.5 years (range 18–79 years).

Results

The mean follow-up period was 57.8 months (range 36–94 months). Overall, 12 (57%) of 21 patients experienced pain relief without medication after the first GKS and the mean time to drug discontinuation was 10.5 months (range 2–24 months). Initial pain improvement was noted in 17 patients (81%) with a mean time of 3.7 months (range 1 week–10 months) after GKS. Eight patients underwent repeated GKS for persistent and recurrent pain. Four patients (50%) had complete pain relief. The final results of the first and repeated GKS were excellent in 16 patients (76%), and in only 1 patient did GKS fail, and this patient later underwent open surgery. For all 21 patients (100%), control of tumor growth was documented at a mean of 46 months after GKS. Three of 6 patients with pre-GKS facial numbness reported improvement, but 4 suffered new facial numbness after repeated GKS.

Conclusions

Gamma Knife surgery appears to be an effective tool to treat benign tumor–related trigeminal pain and control tumor growth. Repeated GKS targeting the trigeminal root or ganglion can be considered a tool to enhance the efficacy of pain management if pain persists or recurs, but the optimum treatment dose needs further investigation.

Operative treatment of trigeminal neuralgia: review of current techniques

Surgical approaches to pain management are performed when medication cannot control pain or patients cannot tolerate the adverse effects of the medication. Microvascular decompression (MVD) is generally performed when the patient is healthy and relatively young. Partial sensory rhizotomy is performed in addition to, or instead of MVD, in patients in whom significant compression of the trigeminal sensory root does not exist or in whom MVD is technically not feasible. Three percutaneous ablative procedures and gamma knife radiosurgery (GKS) are also performed when MVD cannot be performed. The result of MVD is superior to that of the 3 ablative procedures. GKS is inferior to the 3 ablative procedures in terms of initial pain relief and recurrence, but superior in terms of complications. Peripheral procedures are usually performed in patients not suitable for or not wishing to have other procedures. However, no strict rules exist and each patient should be evaluated individually.

Validity of percutaneous controlled radiofrequency thermocoagulation in the treatment of isolated third division trigeminal neuralgia

BACKGROUND

Of 756 percutaneous controlled radiofrequency thermocoagulations of gasserian ganglion and/or retrogasserian rootlets for idiopathic trigeminal neuralgia or for trigeminal neuralgia in multiple sclerosis, the results in 158 patients who had isolated third division trigeminal neuralgia were reviewed.

METHODS

In 129 patients, percutaneous thermocoagulation was fluoroscopic guided, whereas in the last 29 the procedure was performed under CT control. In all cases, the goal was to achieve selective anesthesia limited to the third trigeminal division.

RESULTS

Complete pain relief was obtained immediately after the procedure in all patients and selective anesthesia in the third division was achieved in all of them, except for 2 patients in whom unwanted first and second division anesthesia/hypoesthesia also occurred. Other significant complications were transient sixth cranial nerve palsy in 1 patient and masseter muscle dysfunction, which improved during follow-up, in another one. The selected sensory impairment was well tolerated in all patients. During an average follow-up period of 8.8 years, recurrences occurred in 12 patients, together with a partial regression of the anesthesia: in 10 patients the procedure was repeated successfully. In 2 patients with multiple sclerosis, the procedure was repeated twice and 3 times, respectively.

CONCLUSIONS

Percutaneous controlled radiofrequency thermocoagulation is quite easy to perform under fluoroscopic or CT control, and it involves no mortality and very low morbidity; it is an immediately effective procedure and the rate of recurrence is low. Last, but not least, if the anesthesia is limited to the third division, no anesthesia dolorosa occurs and patients are very grateful.

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

OBJECT

Stereotactic radiosurgery (SRS) with the Gamma Knife (GK) is a rapidly emerging surgical modality in the management of medically refractory idiopathic trigeminal neuralgia (TN). The current study examines the long-term outcome in patients with drug-resistant idiopathic TN who underwent GK surgery at the authors' institution.

METHODS

One hundred and six consecutive patients (38 men and 68 women) with proven medically refractory idiopathic TN were included in this retrospective study. Their ages were 41-82 years (mean 72.3 years). All patients underwent SRS with prescribed maximal radiation doses ranging from 70 to 85 Gy. Isocenters 1-3 were used and plugging was used selectively. The follow-up period was 12-72 months (mean 34.3 months). The patients were divided into 2 groups according to their history of previous surgery.

RESULTS

The initial response rate in patients with no history of previous surgery was 92.9%; in those who had undergone previous surgery, the initial response rate was 85.7%. At the end of the 1st posttreatment year, an excellent outcome was achieved in 82.5% of patients who had not had previous surgery, and in 69.4% of those who had. The respective outcome rates for the 2nd posttreatment year were 78 and 63.5%, respectively. The most common complication was the development of persistent paresthesia, which occurred in 15.8% of patients with no previous surgery and 16.3% of those with previous surgery.

CONCLUSIONS

Stereotactic radiosurgery with the GK is a safe and effective treatment option for patients with medically refractory idiopathic TN.

GAMMA KNIFE RADIOSURGERY FOR TRIGEMINAL NEURALGIA

OBJECTIVE

Gamma knife radiosurgery (GKR) is an increasingly used, minimally invasive treatment option for patients with trigeminal neuralgia (TN) refractory to medical therapy. This retrospective study evaluates the long-term results and side effects of GKR in the treatment of TN focusing on potentially predictive factors.

METHODS

One hundred sixty patients with TN were included in this study (minimum follow-up, &gt;6 mo; mean, 37.4 mo; range, 6–144 mo). In 92 patients, GKR represented the first nonmedical option (“primary GKR”). In 68 patients, invasive treatments had been previously attempted. All patients were treated using a single 4-mm collimator shot targeting the pontine trigeminal root entry zone with a maximal dose of 75 to 95 Gy. Brainstem dose exposure never exceeded 15 Gy. Treatment outcome results were classified as Grade I (pain-free with no pharmacological treatment), Grade II (pain-free with pharmacological treatment), and Grade III (no result). Data were analyzed using the log-rank test for univariate analysis and the ordered logit model for multivariate analysis.

RESULTS

In the overall series, 98 (61%) out of 160 patients reached a Grade I outcome, 45 (29%) reached a Grade II outcome, and 17 (10%) patients had no results from GKR. These results were encouraging for patients with typical facial pain features and for patients treated by a “primary” gamma knife. Considering the global outcome, the most effective and safest dose was found to be in the 80 to 90 Gy range.

CONCLUSION

According to our experience, GKR represents a reliable second-line therapeutic approach for TN after pharmacological failure. Favorable prognostic factors include “primary GKR” and maximal GKR dose ranging between 80 and 90 Gy.

Management of painful neuropathies

Inadequately assessed and poorly managed pain contributes both to high general medical cost and to increasing numbers of societal problems. A large determining factor of inadequate pain care is the lack of understanding about the complex nature of pain and of a rational approach to its assessment and treatment. The less than adequate assessment of neuropathic pain and its relatively poor response to typical analgesic medications are major determinants to the undertreatment of pain. Other than the important management concept of treating the underlying cause, current approaches to the treatment of pain in general, and neuropathic pain in particular, have shifted away from treatment of individual syndromes toward the identification and management of common symptoms and the mechanisms upon which such symptoms are presumed to be based. This article summarizes the features of neuropathic pain that commonly appear in most peripheral neuropathies, regardless of the mechanism of injury, and provides an approach for the selection of treatment.

Impact of radiosurgery on the surgical treatment of trigeminal neuralgia

BACKGROUND

The history of the development of current available techniques to treat TN was reviewed.

METHODS

The largest peer-reviewed publications on the surgical treatment of refractory TN were analyzed, considering the pros and cons of each technique. Results of modern peer-reviewed radiosurgery series were presented, taking into consideration the approach of each research article. Radiation doses and targets for radiosurgery were discussed to maximize the understanding of this technique.

RESULTS

It is concluded that radiosurgery is the least invasive modality with the fewest side effects, although, to match the results of the competing techniques, a substantial number of patients still need some medication intake.

CONCLUSION

Further studies determining the ideal target and radiation dose may bring radiosurgery results to the level of the ones achieved with microvascular decompression, currently considered the gold-standard method.

Outcome of Patients Undergoing Gamma Knife Stereotactic Radiosurgery for Medically Refractory Idiopathic Trigeminal Neuralgia: Medical College of Georgia’s Experience

Gamma knife radiosurgery represents an established treatment option for the management of medically refractory trigeminal neuralgia (TN). In our current communication we present our experience in radiosurgically treating patients with idiopathic TN. Over a period of 5 years, 77 patients underwent gamma knife radiosurgery. The patients were divided into 2 groups based on their previous surgical treatment. In the group of patients with no previous surgeries, the initial response rate was 92.4% (48/52 patients), while in the group with previous surgeries it was 84% (21/25 patients). The excellent outcome rates (complete pain relief with no pain medications) at the completion of 1, 2 and 3 years after treatment for the group with no previous surgeries were: 80.8% (42/52 patients), 69.2% (36/52 patients) and 53.8% (28/52 patients), respectively. The respective excellent outcome rates for the group of patients with previous surgeries were: 64% (16/25 patients), 44% (11/25 patients) and 12% (3/25 patients). The good outcome rates at the completion of 1, 2 and 3 years after treatment for the group with no previous surgeries were: 7.7% (4/52 patients), 11.5% (6/52 patients) and 19.2% (10/52 patients). The respective percentages of good outcome for the patients with previous surgery were: 12% (3/25 patients) at 1 year, 16% (4/25 patients) at 2 years and 32% (8/25 patients) at the completion of 3 years after treatment. The most commonly encountered complication in our series was the development of facial numbness. Our findings confirm previous reports that the presence of preceding surgical interventions represents a negative long-term outcome factor. However, gamma knife radiosurgery constitutes a safe and efficient minimally invasive treatment option for patients with idiopathic TN.

Brainstem and trigeminal nerve changes after radiosurgery for trigeminal pain

PURPOSE

To evaluate the significance of radiological changes on follow-up MRIs after SRS for TN.

MATERIALS AND METHODS

Thirty-seven patients with follow-up MRI because of paresthesias, bilateral treatment, or failure were analyzed regarding pain outcome and complications. Mean age was 64.4 years; 14 underwent previous treatment. Twenty-nine had ETN, 5 secondary TN due to tumor or multiple sclerosis, and 3 had atypical TN. Ninety gray was prescribed for 20 patients, 70 Gy for 5, and 80/85 Gy for 2. A 5-mm collimator was used in 32 (88.9%) cases. Mean follow-up was 15 months (range, 4-52 months).

RESULTS

Excellent/good pain relief was sustained in 67% of cases at 13 months' follow-up. Enhancement on MRIs was observed in 21 cases (56.75%) with nerve enhancement in 9, pons enhancement in 4, pons-nerve enhancement in 4, and tumor enhancement in 4. Magnetic resonance images were unremarkable in 16 cases. Pain recurred in 4 cases (5.5-10 months). Pons enhancement correlated with pain relief (P = .0087) but not with nerve enhancement (P = .22). Incidence of slight paresthesias was 66.6%. No anesthesia dolorosa or ophthalmologic problems were observed. Paresthesias correlated with enhancement (P = .02), but not with brainstem volume encompassed by the 20%, 30%, and 50% isodoseline (P = .689, .525, .908). Enhancement free probability at 12 months was 48.5% (Kaplan-Meier).

CONCLUSIONS

Pons enhancement seems to be prognostic for pain relief without higher incidence of complications. Pons volume irradiated did not predict enhancement occurrence. Radiation delivery to the brainstem-REZ interface seems to improve pain outcome, although more paresthesias should be expected.

Gamma Knife Radiosurgery for Trigeminal Neuralgia: The Washington University Initial Experience

Seventy-three patients were evaluated for the changes in pain relief, numbness and paresthesias after Gamma Knife radiosurgery to a maximum dose of 76-87 Gy for trigeminal neuralgia. Patients experienced pain relief as follows: 59% attained complete pain relief without prior surgery (33% with prior surgery); 25% achieved > or = 50% pain reduction (28% with prior surgery); 11% of surgery patients obtained minor pain relief, and 16% of patients without surgery had no relief (28% with prior surgery). Level of pain decreased rapidly within 6 weeks after radiosurgery. Numbness/paresthesias developed slowly over the first 12-15 months. Bothersome levels were experienced by 15% of the patients without prior surgery (22% with prior surgery). Comparison of the occurrence of numbness/paresthesias, with respect to prior surgery, was not statistically significant. Only 2% of all patients had persistently bothersome side effects. In conclusion, radiosurgery is an effective treatment of trigeminal neuralgia, especially for those patients not having prior surgery.

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

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.

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

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

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.

Dedicated linear accelerator radiosurgery for the treatment of trigeminal neuralgia

OBJECT

In this study the authors evaluate the efficacy of and complications associated with dedicated linear accelerator (LINAC) radiosurgery for trigeminal neuralgia (TN).

METHODS

Between August 1995 and February 2001, 60 patients whose median age was 66.1 years (range 45-88 years) were treated with dedicated LINAC radiosurgery for TN. Forty-one patients (68.3%) had essential TN, 12 (20%) had secondary facial pain, and seven (11.7%) had atypical features. Twenty-nine patients (48.3%) had undergone previous surgical procedures. Radiation doses varied between 70 and 90 Gy (mean 83.3 Gy) at the isocenter, with the last 35 patients (58.3%) treated with a 90-Gy dose. A 5-mm collimator was used in 45 patients (75%) and a 7.5-mm collimator in 15 patients (25%). Treatment was focused at the nerve root entry zone. At last follow up (mean follow-up period 23 months, range 2-70 months), 36 (87.8%) of the 41 patients with essential TN had sustained significant pain relief (good plus excellent results). Twenty-three patients (56.1%) were pain free without medication (excellent outcome), 13 (31.7%) had a 50 to 90% reduction in pain with or without medication (good outcome), and five (12.2%) had minor improvement or no relief. Of 12 patients with secondary facial pain, significant relief was sustained in seven patients (58.3%); worse results were found with atypical pain. Fifteen (25%) of the 60 patients experienced new numbness postprocedure; no other significant complications were found. Pain relief was experienced at a mean of 2.7 months (range 0-12 months).

CONCLUSIONS

Dedicated LINAC radiosurgery is a precise and effective treatment for TN.