Repeat Radiosurgery for Trigeminal Neuralgia

Abstract BACKGROUND: Repeat Gamma Knife radiosurgery (GKRS) is an established option for patients whose pain has recurred after the initial procedure, with reported success rates varying from 68% to 95%. Predictive factors for response to the repeat GKRS are ill-defined. OBJECTIVE: This cohort study aimed to report the outcomes and factors predictive of success for patients who have undergone repeated GKRS for trigeminal neuralgia at Wake Forest University Baptist Medical Center. METHODS: Between 1999 and 2013, 152 patients underwent repeat GKRS at Wake Forest, 125 of whom were available for long-term follow-up. A retrospective chart review and telephone interviews were conducted to determine background medical history, dosimetric data, outcomes, and adverse effects of the procedure. RESULTS: Eighty-four percent of patients achieved at least Barrow Neurological Institute (BNI) IIIb pain relief, with 46% achieving BNI I. The 1-, 3-, and 5-year rates of BNI I pain relief were 63%, 50%, and 37%, respectively. The 1-, 3-, and 5-year rates of BNI IIIb or better pain relief were 74%, 59%, and 46%, respectively. One patient experienced bothersome numbness and 2 patients developed anesthesia dolorosa. The dominant predictive factors for pain relief were facial numbness after the first GKRS and a positive pain response to the first GKRS. CONCLUSION: Repeat GKRS is an effective method of treating recurrent trigeminal neuralgia. Patients who have facial numbness after the first treatment and a positive pain response to the first GKRS are significantly more likely to respond well to the second treatment.

Download Full-text

Gamma Knife Radiosurgery for Trigeminal Neuralgia: A Comparison of Dose Protocols

Brain Sciences ◽

10.3390/brainsci9060134 ◽

2019 ◽

Vol 9 (6) ◽

pp. 134 ◽

Cited By ~ 2

Author(s):

Warren Boling ◽

Minwoo Song ◽

Wendy Shih ◽

Bengt Karlsson

Keyword(s):

Patient Satisfaction ◽

Pain Relief ◽

Trigeminal Neuralgia ◽

Gamma Knife Radiosurgery ◽

Sensory Disturbance ◽

Kaplan Meier ◽

Facial Numbness ◽

Satisfaction With Treatment ◽

Treatment Plans ◽

Prescription Dose

Purpose: A variety of treatment plans including an array of prescription doses have been used in radiosurgery treatment of trigeminal neuralgia (TN). However, despite a considerable experience in the radiosurgical treatment of TN, an ideal prescription dose that balances facial dysesthesia risk with pain relief durability has not been determined. Methods and Materials: This retrospective study of patients treated with radiosurgery for typical TN evaluates two treatment doses in relation to outcomes of pain freedom, bothersome facial numbness, and patient satisfaction with treatment. All patients were treated with radiosurgery for intractable and disabling TN. A treatment dose protocol change from 80 to 85 Gy provided an opportunity to compare two prescription doses. The variables evaluated were pain relief, treatment side-effect profile, and patient satisfaction. Results: Typical TN was treated with 80 Gy in 26 patients, and 85 Gy in 37 patients. A new face sensory disturbance was reported after 80 Gy in 16% and after 85 Gy in 27% (p = 0.4). Thirteen failed an 80 Gy dose whereas seven failed an 85 Gy dose. Kaplan–Meier analysis found that at 29 months 50% failed an 80 Gy treatment compared with 79% who had durable pain relief after 85 Gy treatment (p = 0.04). Conclusion: The 85 Gy dose for TN provided a more durable pain relief compared to the 80 Gy one without a significantly elevated occurrence of facial sensory disturbance.

Download Full-text

Repeat Gamma Knife radiosurgery versus microvascular decompression following failure of GKRS in trigeminal neuralgia: a systematic review and meta-analysis

Journal of Neurosurgery ◽

10.3171/2018.5.jns18583 ◽

2019 ◽

Vol 131 (4) ◽

pp. 1197-1206 ◽

Cited By ~ 2

Author(s):

Devi Prasad Patra ◽

Amey Rajan Savardekar ◽

Rimal Hanif Dossani ◽

Vinayak Narayan ◽

Nasser Mohammed ◽

...

Keyword(s):

Systematic Review ◽

Pain Relief ◽

Trigeminal Neuralgia ◽

Microvascular Decompression ◽

Treatment Modality ◽

Meta Analysis ◽

Gamma Knife Radiosurgery ◽

Facial Numbness ◽

Retreatment Rate ◽

Secondary Outcomes

OBJECTIVEGamma Knife radiosurgery (GKRS) has emerged as a promising treatment modality for patients with classical trigeminal neuralgia (TN); however, considering that almost half of the patients experience post-GKRS failure or lesion recurrence, a repeat treatment is typically necessary. The existing literature does not offer clear evidence to establish which treatment modality, repeat GKRS or microvascular decompression (MVD), is superior. The present study aimed to compare the overall outcome of patients who have undergone either repeat GKRS or MVD after failure of their primary GKRS; the authors do so by conducting a systematic review and meta-analysis of the literature and analysis of data from their own institution.METHODSThe authors conducted a systematic review and meta-analysis of the PubMed, Cochrane Library, Web of Science, and CINAHL databases to identify studies describing patients who underwent either repeat GKRS or MVD after initial failed GKRS for TN. The primary outcomes were complete pain relief (CPR) and adequate pain relief (APR) at 1 year. The secondary outcomes were rate of postoperative facial numbness and the retreatment rate. The pooled data were analyzed with R software. Bias and heterogeneity were assessed using funnel plots and I2 tests, respectively. A retrospective analysis of a series of patients treated by the authors who underwent repeat GKRS or MVD after post-GKRS failure or relapse is presented.RESULTSA total of 22 studies met the selection criteria and were included for final data retrieval and meta-analysis. The search did not identify any study that had directly compared outcomes between patients who had undergone repeat GKRS versus those who had undergone MVD. Therefore, the authors’ final analysis included two groups: studies describing outcome after repeat GKRS (n = 17) and studies describing outcome after MVD (n = 5). The authors’ institutional study was the only study with direct comparison of the two cohorts. The pooled estimates of primary outcomes were APR in 83% of patients who underwent repeat GKRS and 88% of those who underwent MVD (p = 0.49), and CPR in 46% of patients who underwent repeat GKRS and 72% of those who underwent MVD (p = 0.02). The pooled estimates of secondary outcomes were facial numbness in 32% of patients who underwent repeat GKRS and 22% of those who underwent MVD (p = 0.11); the retreatment rate was 19% in patients who underwent repeat GKRS and 13% in those who underwent MVD (p = 0.74). The authors’ institutional study included 42 patients (repeat GKRS in 15 and MVD in 27), and the outcomes 1 year after retreatment were APR in 80% of those who underwent repeat GKRS and 81% in those who underwent MVD (p = 1.0); CPR was achieved in 47% of those who underwent repeat GKRS and 44% in those who underwent MVD (p = 1.0). There was no difference in the rate of postoperative facial numbness or retreatment.CONCLUSIONSThe current meta-analysis failed to identify any superiority of one treatment over the other with comparable outcomes in terms of APR, postoperative facial numbness, and retreatment rates. However, MVD was shown to provide a better chance of CPR compared with repeat GKRS.

Download Full-text

Effectiveness of Gamma Knife Radiosurgery in the Treatment of Refractory Trigeminal Neuralgia: A Case Series

Operative Neurosurgery ◽

10.1093/ons/opz311 ◽

2019 ◽

Vol 18 (6) ◽

pp. 571-576 ◽

Cited By ~ 1

Author(s):

Sherwin Tavakol ◽

Anna Jackanich ◽

Ben A Strickland ◽

Michael Marietta ◽

Kristine Ravina ◽

...

Keyword(s):

Pain Relief ◽

Trigeminal Neuralgia ◽

Gamma Knife ◽

Symptom Relief ◽

Gamma Knife Radiosurgery ◽

Case Series ◽

Pain Scale ◽

Success Rates ◽

Surgical Interventions ◽

Pain Outcomes

Abstract BACKGROUND Medical management is the first line of treatment for trigeminal neuralgia (TN). Patients with medically refractory TN may undergo a variety of invasive surgical interventions with varying success rates. Management of TN refractory to both medical and surgical intervention remains somewhat controversial. OBJECTIVE To assess the effectiveness of Gamma Knife radiosurgery (GKRS; Elekta Instruments AB) for medically refractory TN. METHODS A retrospective review was conducted for 57 cases (47 patients) who underwent GKRS for refractory TN at our institution between 2005 and 2018. TN pain outcomes were evaluated using the Barrow Neurological Institute (BNI) Pain Scale. A good outcome was defined by post-GKRS BNI score of I-III, whereas treatment failure was defined BNI score IV-V. RESULTS Of the total 57 GKRS procedures, 47 (82.5%) had good outcomes. A total of 22 patients (46.8%) experienced complete pain relief off medications (BNI I). The average time to pain relief was 30 d (range 1-120 d). Prior invasive surgical treatment for TN was not found to have a significant impact on GKRS outcomes (P = .32). Target and treatment volumes were not found to correlate significantly with GKRS outcomes (.47 and .47, respectively). Complications included 2 cases (4.2%) of facial numbness. A total of 37 patients (78.7%) did not have any additional invasive surgical interventions following GKRS treatment. CONCLUSION GKRS is a safe and effective treatment modality for both medically and surgically refractory TN. Complete symptom relief was possible in patients with prior surgical or GKRS treatments. Recurrent symptoms following surgery or GKRS should not exclude a patient from future GKRS consideration.

Download Full-text

Gamma Knife Radiosurgery for Multiple Sclerosis-Associated Trigeminal Neuralgia

Neurosurgery ◽

10.1093/neuros/nyz182 ◽

2019 ◽

Vol 85 (5) ◽

pp. E933-E939 ◽

Cited By ~ 2

Author(s):

Corbin A Helis ◽

Emory McTyre ◽

Michael T Munley ◽

J Daniel Bourland ◽

John T Lucas ◽

...

Keyword(s):

Multiple Sclerosis ◽

Cohort Study ◽

Pain Relief ◽

Trigeminal Neuralgia ◽

Gamma Knife ◽

Median Duration ◽

Gamma Knife Radiosurgery ◽

Historical Cohort ◽

Telephone Interviews ◽

Dosimetric Data

Abstract BACKGROUND Trigeminal neuralgia in the setting of multiple sclerosis (MS-TN) is a challenging condition to manage that is commonly treated with Gamma Knife radiosurgery (GKRS; Elekta AB). However, data regarding the efficacy of this treatment are somewhat limited, particularly for repeat GKRS. OBJECTIVE To report outcomes of GKRS for MS-TN from a cohort study. METHODS Retrospective review of our GKRS database identified 77 cases of unilateral MS-TN (UMSTN) in 74 patients treated with GKRS between 2001 and 2016, with 37 cases undergoing repeat GKRS. Background medical history, treatment outcomes and complications, and dosimetric data were obtained by retrospective chart reviews and telephone interviews. RESULTS Eighty-two percent of UMSTN cases achieved Barrow Neurological Institute (BNI) IIIb or better pain relief following initial GKRS for a median duration of 1.1 yr. Estimated rates of pain relief at 1, 3, and 5 yr were 51, 39, and 29% respectively. Eighty-eight percent achieved BNI IIIb or better pain relief after repeat GKRS for a median duration of 4.0 yr. Estimated rates of pain relief at 1 and 3 yr were 70 and 54%, respectively. Median doses for initial and repeat GKRS were 85 and 80 Gy to the 100% isodose line, respectively. Those with MS-TN had a shorter duration of BNI IIIb or better pain relief after initial (4.6 vs 1.1 yr), but not repeat GKRS (3.8 vs 4.0 yr) compared to a historical cohort from our institution. CONCLUSION GKRS is an effective, well-tolerated treatment for patients with MS-TN. More durable relief is often achieved with repeat GKRS.

Download Full-text

Results of repeated gamma knife radiosurgery for medically unresponsive trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/jns.2000.93.supplement_3.0162 ◽

2000 ◽

Vol 93 (supplement_3) ◽

pp. 162-164 ◽

Cited By ~ 38

Author(s):

Bruce E. Pollock ◽

Robert L. Foote ◽

Scott L. Stafford ◽

Michael J. Link ◽

Deborah A. Gorman ◽

...

Keyword(s):

Pain Relief ◽

Trigeminal Neuralgia ◽

Gamma Knife ◽

Facial Pain ◽

Gamma Knife Radiosurgery ◽

Neurological Dysfunction ◽

Content Type ◽

Additional Surgery ◽

Facial Numbness ◽

Fine Print

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.

Download Full-text

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

International Journal of Otolaryngology ◽

10.1155/2012/919186 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 8

Author(s):

Ameer L. Elaimy ◽

Peter W. Hanson ◽

Wayne T. Lamoreaux ◽

Alexander R. Mackay ◽

John J. Demakas ◽

...

Keyword(s):

Pain Relief ◽

Trigeminal Neuralgia ◽

Gamma Knife ◽

Pain Control ◽

Facial Pain ◽

Gamma Knife Radiosurgery ◽

Management Approach ◽

Review Of The Literature ◽

Facial Numbness ◽

Sensory Changes

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

Download Full-text

Gamma Knife radiosurgery for bilateral trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/2018.6.jns172646 ◽

2019 ◽

Vol 131 (5) ◽

pp. 1591-1598

Author(s):

Corbin A. Helis ◽

Emory McTyre ◽

Michael T. Munley ◽

J. Daniel Bourland ◽

John T. Lucas ◽

...

Keyword(s):

Pain Relief ◽

Trigeminal Neuralgia ◽

Treatment Outcomes ◽

Gamma Knife ◽

Median Duration ◽

Gamma Knife Radiosurgery ◽

Persistent Symptoms ◽

Significant Difference ◽

Facial Numbness

OBJECTIVEA small subset of patients with trigeminal neuralgia (TN) will experience bilateral symptoms. Treatment in these patients is controversial because the population is heterogeneous and patients may have nonvascular etiologies of their pain. This study reports treatment outcomes in the largest cohort of patients with bilateral TN who have undergone Gamma Knife radiosurgery (GKRS) to date.METHODSA retrospective chart review identified 51 individual nerves in 34 patients with bilateral TN who were treated with GKRS at the authors’ institution between 2001 and 2015, with 12 nerves in 11 patients undergoing repeat GKRS for recurrent or persistent symptoms. Long-term follow-up was obtained by telephone interview. Pain outcomes were measured using the Barrow Neurological Institute (BNI) pain scale, with BNI IIIb or better considered a successful treatment.RESULTSThere was sufficient follow-up to determine treatment outcomes for 48 individual nerves in 33 patients. Of these nerves, 42 (88%) achieved at least BNI IIIb pain relief. The median duration of pain relief was 1.9 years, and 1-, 3-, and 5-year pain relief rates were 64%, 44%, and 44%, respectively. No patients experienced bothersome facial numbness, and 1 case of anesthesia dolorosa and 2 cases of corneal dryness were reported. Patients with a history of definite or possible multiple sclerosis were significantly more likely to experience BNI IV–V relapse. There was no statistically significant difference in treatment outcomes between patients in this series versus a large cohort of patients with unilateral TN treated at the authors’ institution. There was sufficient follow-up to determine treatment outcomes for 11 individual nerves in 10 patients treated with repeat GKRS. Ten nerves (91%) improved to at least BNI IIIb after treatment. The median duration of pain relief was 2.8 years, with 1-, 3-, and 5-year rates of pain relief of 79%, 53%, and 53%, respectively. There was no statistically significant difference in outcomes between initial and repeat GKRS. One case of bothersome facial numbness and 1 case of corneal dryness were reported, with no patients developing anesthesia dolorosa with retreatment.CONCLUSIONSGKRS is a safe, well-tolerated treatment for patients with medically refractory bilateral TN. Efficacy of treatment appears similar to that in patients with unilateral TN. GKRS can be safely repeated in this population if necessary.

Download Full-text

Results of a third Gamma Knife radiosurgery for trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/2020.2.jns192876 ◽

2020 ◽

pp. 1-7

Author(s):

Corbin A. Helis ◽

Ryan T. Hughes ◽

Michael T. Munley ◽

J. Daniel Bourland ◽

Travis Jacobson ◽

...

Keyword(s):

Pain Relief ◽

Trigeminal Neuralgia ◽

Gamma Knife ◽

Treatment Success ◽

Gamma Knife Radiosurgery ◽

The Third ◽

Significant Difference ◽

Pain Outcomes ◽

Facial Numbness

OBJECTIVEGamma Knife radiosurgery (GKRS) is a commonly used procedure for medically refractory trigeminal neuralgia (TN), with repeat GKRS routinely done in cases of pain relapse. The results of a third GKRS in cases of further pain relapse have not been well described. In this study, the authors report the largest series of patients treated with a third GKRS for TN to date.METHODSRetrospective review of institutional electronic medical records and a GKRS database was performed to identify patients who had been treated with a third GKRS at the authors’ institution in the period from 2010 to 2018. Telephone interviews were used to collect long-term follow-up data. Pain outcomes were measured using the Barrow Neurological Institute (BNI) pain intensity scale, with a score ≤ IIIb indicating successful treatment.RESULTSTwenty-two nerves in 21 patients had sufficient follow-up to determine BNI pain score outcomes. Eighteen of 22 cases had a successful third GKRS, with a median durability of pain relief of 3.88 years. There was no significant difference in the durability of pain relief after a third GKRS compared with those of institutional historical controls of prior series of first and second GKRS procedures. Ten cases had new or worsening facial numbness, with 1 case being bothersome. Four cases of toxicity other than facial numbness were reported, including 1 case of corneal abrasions and possible neurotrophic keratopathy. No cases of anesthesia dolorosa were reported. No factors predicting treatment success or the durability of pain relief were identified. Nonnumbness toxicity was more common in those with a proximally placed shot at the third GKRS.CONCLUSIONSA third GKRS is an effective treatment option for TN patients who have pain relapse after repeat GKRS. Pain outcomes of a third GKRS are similar to those following a first or second GKRS. Toxicity is tolerable in patients with a distally placed shot at the third GKRS.

Download Full-text

Percutaneous glycerol rhizotomy for trigeminal neuralgia in patients with multiple sclerosis: a long-term retrospective cohort study

Journal of Neurosurgery ◽

10.3171/2019.1.jns183093 ◽

2020 ◽

Vol 132 (5) ◽

pp. 1405-1413 ◽

Cited By ~ 1

Author(s):

Michael D. Staudt ◽

Holger Joswig ◽

Gwynedd E. Pickett ◽

Keith W. MacDougall ◽

Andrew G. Parrent

Keyword(s):

Multiple Sclerosis ◽

Pain Relief ◽

Trigeminal Neuralgia ◽

Retrospective Chart Review ◽

Medication Usage ◽

Free Response ◽

Free Survival ◽

Time To Recurrence ◽

Significant Difference

OBJECTIVEThe prevalence of trigeminal neuralgia (TN) in patients with multiple sclerosis (MS-TN) is higher than in the general population (idiopathic TN [ITN]). Glycerol rhizotomy (GR) is a percutaneous lesioning surgery commonly performed for the treatment of medically refractory TN. While treatment for acute pain relief is excellent, long-term pain relief is poorer. The object of this study was to assess the efficacy of percutaneous retrogasserian GR for the treatment of MS-TN versus ITN.METHODSA retrospective chart review was performed, identifying 219 patients who had undergone 401 GR procedures from 1983 to 2018 at a single academic institution. All patients were diagnosed with medically refractory MS-TN (182 procedures) or ITN (219 procedures). The primary outcome measures of interest were immediate pain relief and time to pain recurrence following initial and repeat GR procedures. Secondary outcomes included medication usage and presence of periprocedural hypesthesia.RESULTSThe initial pain-free response rate was similar between groups (p = 0.726): MS-TN initial GR 89.6%; MS-TN repeat GR 91.9%; ITN initial GR 89.6%; ITN repeat GR 87.0%. The median time to recurrence after initial GR was similar between MS-TN (2.7 ± 1.3 years) and ITN (2.1 ± 0.6 years) patients (p = 0.87). However, there was a statistically significant difference in the time to recurrence after repeat GR between MS-TN (2.3 ± 0.5 years) and ITN patients (1.2 ± 0.2 years; p < 0.05). The presence of periprocedural hypesthesia was highly predictive of pain-free survival (p < 0.01).CONCLUSIONSPatients with MS-TN achieve meaningful pain relief following GR, with an efficacy comparable to that following GR in patients with ITN. Initial and subsequent GR procedures are equally efficacious.

Download Full-text

Temporal disconnection between pain relief and trigeminal nerve microstructural changes after Gamma Knife radiosurgery for trigeminal neuralgia

Journal of Neurosurgery ◽

10.3171/2019.4.jns19380 ◽

2020 ◽

Vol 133 (3) ◽

pp. 727-735

Author(s):

Peter Shih-Ping Hung ◽

Sarasa Tohyama ◽

Jia Y. Zhang ◽

Mojgan Hodaie

Keyword(s):

Pain Relief ◽

Trigeminal Neuralgia ◽

Pain Intensity ◽

Gamma Knife ◽

Trigeminal Nerve ◽

Diffusion Tensor ◽

Gamma Knife Radiosurgery ◽

Time Points ◽

Microstructural Effect

OBJECTIVEGamma Knife radiosurgery (GKRS) is a noninvasive surgical treatment option for patients with medically refractive classic trigeminal neuralgia (TN). The long-term microstructural consequences of radiosurgery and their association with pain relief remain unclear. To better understand this topic, the authors used diffusion tensor imaging (DTI) to characterize the effects of GKRS on trigeminal nerve microstructure over multiple posttreatment time points.METHODSNinety-two sets of 3-T anatomical and diffusion-weighted MR images from 55 patients with TN treated by GKRS were divided within 6-, 12-, and 24-month posttreatment time points into responder and nonresponder subgroups (≥ 75% and < 75% reduction in posttreatment pain intensity, respectively). Within each subgroup, posttreatment pain intensity was then assessed against pretreatment levels and followed by DTI metric analyses, contrasting treated and contralateral control nerves to identify specific biomarkers of successful pain relief.RESULTSGKRS resulted in successful pain relief that was accompanied by asynchronous reductions in fractional anisotropy (FA), which maximized 24 months after treatment. While GKRS responders demonstrated significantly reduced FA within the radiosurgery target 12 and 24 months posttreatment (p < 0.05 and p < 0.01, respectively), nonresponders had statistically indistinguishable DTI metrics between nerve types at each time point.CONCLUSIONSUltimately, this study serves as the first step toward an improved understanding of the long-term microstructural effect of radiosurgery on TN. Given that FA reductions remained specific to responders and were absent in nonresponders up to 24 months posttreatment, FA changes have the potential of serving as temporally consistent biomarkers of optimal pain relief following radiosurgical treatment for classic TN.

Download Full-text