Gamma knife radiosurgery for trigeminal neuralgia: dose—volume histograms of the brainstem and trigeminal nerve

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 155-158 ◽  
Author(s):  
Ronald Brisman ◽  
R. Mooij

Object. The purpose of this study was to assess the relationship between the volume of brainstem that receives 20% or more of the maximum dose (VB20) and the volume of the trigeminal nerve that receives 50% or more of the maximum dose (VT50) on clinical outcome following gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). Methods. Patients with TN were treated with a single 4-mm isocenter with a maximum dose of 75 Gy directed at the trigeminal nerve close to where it leaves the brainstem. The VB20 and VT50, as determined on dose—volume histograms, were correlated with clinical outcomes at 6 and 12 months, laterality, presence of multiple sclerosis (MS), and each other. At 6 months excellent pain relief (no pain or required medicine) was achieved in 27 of 48 patients (p = 0.009) when VB20 was greater than or equal to 20 mm3 and in 25 of 78 when VB20 was less than 20 mm3, when all patients are considered. At 12 months excellent pain relief was achieved in 16 of 32 patients (p = 0.038) when VB20 was greater than or equal to 20 mm3 and in 14 of 52 when VB20 less than 20 mm3, when all patients are considered. When VB20 was less than 20 mm3 in MS patients, five of 21 had an excellent result at 6 months and two of 13 at 12 months. The VB20 was 20 mm3 or more in 38 of 64 on the right side and in eight of 41 on the left side (p < 0.001) in patients with TN and without MS. There is a difference between left and right dose—volume histograms even when the same isodose is placed on the surface of the brainstem. The VB20 was 20 mm3 or more in 45 of 105 patients with TN and without MS but in only three of 21 patients with TN and MS (p = 0.014). There was an inverse relationship between VB20 and VT50 (p = 0.01). Conclusions. Isocenter proximity to the brainstem, as reflected in a higher VB20, is associated with a greater chance of excellent outcome at 6 and 12 months. Worse results in patients with TN and MS may be partly explained by a lower VB20.

2002 ◽  
Vol 97 ◽  
pp. 529-532 ◽  
Author(s):  
C. Leland Rogers ◽  
Andrew G. Shetter ◽  
Francisco A. Ponce ◽  
Jeffrey A. Fiedler ◽  
Kris A. Smith ◽  
...  

Object. The authors assessed the efficacy and complications from gamma knife radiosurgery (GKS) for multiple sclerosis (MS)-associated trigeminal neuralgia (TN). Methods. There were 15 patients with MS-associated TN (MS—TN). Treatment involved three sequential protocols, 70 to 90-Gy maximum dose, using a single 4-mm isocenter targeting the ipsilateral trigeminal nerve at its junction with the pons with the 50% isodose. Pain was appraised by each patient by using Barrow Neurological Institute (BNI) Scores I through IV: I, no pain; II, occasional pain not requiring medication; IIIa, no pain but continued medication; IIIb, some pain, controlled with medication; IV, some pain, not controlled with medication; and V, severe pain/no pain relief. With a mean follow up of 17 months (range 6–38 months), 12 (80%) of 15 patients experienced pain relief. Three patients (20%) reported no relief (BNI Score V). For responders, the mean latency from treatment to the onset of pain relief was 13 days (range 1–61 days). Maximal relief was achieved after a mean latency of 56 days (range 1–157 days). Five patients underwent a second GKS after a mean interval of 534 days (range 231–946 days). The mean maximum dose at this second treatment was 48 Gy. The target was unchanged from the first treatment. All five patients who underwent repeated GKS improved. Complications were limited to delayed facial hypesthesias. Two (13%) of 15 patients experienced onset of numbness after the first GKS, as well as two of five patients following a second GKS. The patients found this mild and not bothersome. Each patient who developed hypesthesias also experienced complete pain relief. Conclusions. Gamma knife radiosurgery is an effective treatment for MS—TN. Radiosurgery carries an acceptable small risk of mild facial hypesthesias, and hypesthesia appears predictive of a favorable outcome.


2002 ◽  
Vol 97 ◽  
pp. 525-528 ◽  
Author(s):  
Shinji Matsuda ◽  
Toru Serizawa ◽  
Makato Sato ◽  
Junichi Ono

Object. The purpose of this paper is to report a unique complication of gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). The nature of this complication and its related factors are discussed. Methods. Forty-one medically refractory patients with TN were treated with GKS. All patients received 80 Gy to the proximal trigeminal nerve root, using a 4-mm collimator and a single isocenter. Follow up consisted of three monthly outpatient sessions after GKS. Improvement, recurrence, complications, and changes in magnetic resonance imaging were recorded. To evaluate the factors behind the complications, a subgroup of 33 patients was assessed in whom the follow-up duration was more than 9 months. The follow-up duration was 3 to 36 months (mean 13 months). The results were excellent in 20 patients, good in 11, and fair in seven. No patient had a poor result. Three patients suffered recurrences. Seven patients suffered complications 9 to 24 months after GKS. All seven patients complained of facial numbness and hypesthesia was recorded. Three of them also complained of “dry eye” with diminution or absence of corneal reflex but no other abnormalities of the cornea and conjunctiva were found on ophthalmological examination. In these three patients, hypesthesia of the first division of the trigeminal nerve area had been found before their “dry eye” symptoms appeared. The irradiated volume on the brainstem was significantly related to this complication. Conclusions. The dry eye symptom seems to be a special form of sensory disturbance. An overdose of radiation to the brainstem may play an important role in the manifestation of this complication.


2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 159-161 ◽  
Author(s):  
Ronald Brisman

Object. The purpose of this study was to assess the efficacy of gamma knife radiosurgery (GKS) as the primary rather than secondary management for trigeminal neuralgia. Methods. Eighty-two patients underwent GKS as their first neurosurgical intervention (Group A), and 90 patients underwent GKS following a different procedure (Group B). All GKS patients were treated with a maximum dose of 75 Gy. The single 4-mm isocenter was placed close to the junction of the trigeminal nerve and the brainstem. Six-month follow up was available for 126 patients and 12-month follow up for 84 patients. Excellent (no pain and no medicine) or good (at least 50% reduction in pain and less medicine) relief was more likely to occur in Group A than in Group B patients 6 and 12 months following GKS for trigeminal neuralgia (p = 0.058). Excellent or good results were also more likely in patients with trigeminal neuralgia without multiple sclerosis (MS) (p = 0.042). The number and type of procedures performed prior to GKS, the interval between the last procedure and GKS, and the interval from first symptom to GKS (within Groups A and B) did not affect 6-month outcome. The interval between first symptom and GKS was shorter in Group A patients without MS (87 months) than in Group B (148 months; p < 0.004). There were no significant differences between Group A and B patients with regard to sex, age, or laterality. Conclusions. Patients with trigeminal neuralgia who are treated with GKS as primary management have better pain relief than those treated with GKS as secondary management. Patients are more likely to have pain relief if they do not have MS.


2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 165-168 ◽  
Author(s):  
Dušan Urgošík ◽  
Josef Vymazal ◽  
Vilibald Vladyka ◽  
Roman Liščák

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


2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 162-164 ◽  
Author(s):  
Bruce E. Pollock ◽  
Robert L. Foote ◽  
Scott L. Stafford ◽  
Michael J. Link ◽  
Deborah A. Gorman ◽  
...  

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.


2020 ◽  
Vol 133 (3) ◽  
pp. 727-735
Author(s):  
Peter Shih-Ping Hung ◽  
Sarasa Tohyama ◽  
Jia Y. Zhang ◽  
Mojgan Hodaie

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.


2002 ◽  
Vol 97 ◽  
pp. 533-535 ◽  
Author(s):  
Jin Woo Chang ◽  
Jae Young Choi ◽  
Young Sul Yoon ◽  
Yong Gou Park ◽  
Sang Sup Chung

✓ The purpose of this paper was to present two cases of secondary trigeminal neuralgia (TN) with an unusual origin and lesion location. In two cases TN was caused by lesions along the course of the trigeminal nerve within the pons and adjacent to the fourth ventricle. Both cases presented with typical TN. Brain magnetic resonance imaging revealed linear or wedge-shaped lesions adjacent to the fourth ventricle, extending anterolaterally and lying along the pathway of the intraaxial trigeminal fibers. The involvement of the nucleus of the spinal trigeminal tract and of the principal sensory trigeminal nucleus with segmental demyelination are suggested as possible causes for trigeminal pain in these cases. It is postulated that these lesions are the result of an old viral neuritis. The patients underwent gamma knife radiosurgery and their clinical responses have been encouraging to date.


2005 ◽  
Vol 102 ◽  
pp. 107-110 ◽  
Author(s):  
Vasilios A. Zerris ◽  
Georg C. Noren ◽  
William A. Shucart ◽  
Jeff Rogg ◽  
Gerhard M. Friehs

Object.The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.Methods.Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.Conclusions.The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.


2004 ◽  
Vol 100 (5) ◽  
pp. 848-854 ◽  
Author(s):  
Ronald Brisman

Object. The author presents a large series of patients with idiopathic trigeminal neuralgia (TN) who were treated with gamma knife surgery (GKS), at a maximum dose of 75 to 76.8 Gy, and followed up in a nearly uniform manner for up to 4.6 years. Methods. Two hundred ninety-three patients were treated and followed up for at least 6 months (range 0.4–4.6 years, median 1.9 years). At the final follow-up review, there was complete (100%) pain relief without medicines in 64 patients (21.8%), 90% or greater relief with or without small doses of medicines in 86 (29.4%), between 75 and 89% relief in 31 (10.6%), between 50 and 74% relief in 19 (6.5%), and less than 50% relief in 23 patients (7.8%). Recurrent pain requiring a second procedure occurred in 70 patients (23.9%). Kaplan—Meier analysis showed that 100%, 90% or greater, and 50% or greater pain relief was obtained and maintained for 3.5 to 4.1 years in 5.6 , 23.7, and 50.4% patients, respectively. Of 31 patients who described pain relief ranging from 75 to 89%, 80% of patients described it as good and 10% as excellent; of 17 patients who reported between 50 and 74% pain relief, 53% described it as good and none as excellent (p = 0.014). Dysesthesia scores greater than 5 (scale of 0–10, in which a score of 10 represents excruciating pain) occurred in four (3.2%) of 126 patients who had not undergone prior surgery; all these patients obtained either good or excellent relief from TN pain. There were 36 patients in whom the TN had atypical features; these patients were less likely to attain at least 50% or at least 90% pain relief compared with those without atypical TN features (p = 0.001). Conclusions. Gamma knife surgery is a safe and effective way to relieve TN. Patients who attain between 75 and 89% pain relief are much more likely to describe this outcome as good or excellent than those who attain between 50 and 74% pain relief.


1999 ◽  
Vol 90 (1) ◽  
pp. 145-147 ◽  
Author(s):  
Miroslav P. Bobek ◽  
Oren Sagher

✓ The authors present the case of a 47-year-old man who, after undergoing microvascular decompression for trigeminal neuralgia, experienced symptomatic pain relief but developed prolonged aseptic meningitis. This case is unusual in that the patient remained dependent on steroid medications for nearly 5 months following the initial surgery and the aseptic meningitis did not resolve until after surgical removal of the Teflon used to pad the trigeminal nerve. The pathophysiological characteristics of the body's reaction to implanted Teflon are discussed along with the rationale for removing this substance in cases of prolonged intractable aseptic meningitis.


Sign in / Sign up

Export Citation Format

Share Document