title: Long-term outcome of gamma knife surgery using a retrogasserian petrous bone target for classic trigeminal neuralgia.
abstract: BACKGROUND
  Gamma knife surgery (GKS) is the prevailing method for treatment of medically intractable trigeminal neuralgia (TN), although there are some technical differences among radiosurgical centers. We assessed the long-term outcomes of GKS using retrogasserian petrous bone targeting and evaluated factors associated with the clinical outcomes.
  
  
  METHODS
  Between December 2003 and June 2009, a total of 91 GKS treatments were performed in 90 patients with classic TN. The surgical target was defined at the anterior portion of the trigeminal nerve, just above the retrogasserian petrous bone. A single 4-mm collimator was used to deliver a median 88.0 Gy (range 75-90 Gy) dose of radiation.
  
  
  RESULTS
  During follow-up, which ranged from 24 to 90 months, 89 patients (97.8 %) reported initial pain relief, 75 (82.4 %) experienced pain control, and 47 (51.6 %) achieved a pain-free state without medications at the last follow-up. Barrow Neurological Institute (BNI) scores of I-III at 2, 3, 4, 5, and 7 years were observed in 84 of 91, 68 of 77, 46 of 53, 33 of 36, 17 of 19, and 7 of 7 patients, respectively. Trigeminal nerve dysfunction was experienced by 34 patients, with 12 having BNI facial numbness scores of III-IV (13.2 %). In all, 14 patients (15.4 %) experienced pain recurrence at a mean 32 months (range 10-62 months) after treatment. The actuarial rates of pain control at 2, 4, and 6 years were 93 %, 88 %, and 79 %, respectively.
  
  
  CONCLUSIONS
  Gamma Knife radiosurgery is an efficient option for intractable TN. Our results can help medical practitioners to counsel their patients on the likelihood of achieving successful pain control.
authors: Department of Neurosurgery, Asan Medical Center, University of Ulsan, College of Medicine, 88, Olympic Ro 43-Gil, Songpa-Gu, Seoul, 138-736, Korea. jklee3745@gmail.com
authors: Jung Kyo
authors: JK
authors: Lee
authors: Deok Ryeong
authors: DR
authors: Kim
authors: Yeon Hee
authors: YH
authors: Huh
authors: Jin Kyung
authors: JK
authors: Kim
authors: Won Chul
authors: WC
authors: Namgung
authors: Seok Ho
authors: SH
authors: Hong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001933:Brain Stem / Q000473:pathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010579:Petrous Bone / Q000601:surgery*; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014276:Trigeminal Nerve / Q000473:pathology; D014277:Trigeminal Neuralgia / Q000000981:diagnostic imaging / Q000601:surgery*