title: Linear accelerator-based flattening-filter-free stereotactic radiosurgery for trigeminal neuralgia: Feasibility and patient-reported outcomes.
abstract: OBJECTIVE
  The purpose of this study was to assess the safety and outcomes of the clinical use of LINAC (linear accelerator)-based flattening-filter-free beams for delivering ablative stereotactic radiosurgery (SRS) for trigeminal neuralgia (TN).
  
  
  METHODS
  Thirty-six consecutive patients (34 unique patients) followed up by a single neurosurgeon and diagnosed with medically refractory unilateral TN were treated with SRS. There were 14 left-sided cases (41%) and 20 right-sided cases (59%). Twenty-eight of the patients (82%) had type 1 TN, and 6 (18%) had type 2 TN. Previous treatments were as follows: 10 patients (29%) had SRS to the ipsilateral TN (8 with Gamma Knife, 2 with LINAC), 4 (12%) had percutaneous rhizotomy, and 3 (9%) had microvascular decompression. A median prescription dose of 75 Gy (range, 70-80 Gy), prescribed to the 100% isodose line, was delivered in a single fraction. Before treatment delivery, image guidance verified stereotactic frame placement, head position, and final isocenter. The volume of brainstem receiving ≥10 Gy was <0.5 cm(3). At each visit, patients prospectively reported outcomes using the Barrow Neurological Institute (BNI) pain scale.
  
  
  RESULTS
  With a median follow-up of 3.1 months (range, 0.6-24.3; mean, 5.5 months), no patient experienced grade 1+ toxicities. There were no new episodes of dysesthesia, hypoesthesia, or long-term complications related to SRS. Median baseline (pre-SRS) BNI score was 5.0 (mean, 4.7). Clinical assessment at first follow-up (median, 1 month) demonstrated a median BNI score of 3.0 (mean, 3.1). When stratified by TN subtype, both type 1 and type 2 TN patients had a median BNI score of 3.0 at first follow-up. Thirty patients (88.2%) achieved a reduction in their BNI at their first follow-up, and 5 patients (15%) achieved a score <3, which represents medication-free pain relief. The median BNI at second follow-up (average, 6.3 months) was 2.5.
  
  
  CONCLUSIONS
  We report our experience with modern LINAC-based SRS using flattening-filter-free beams for TN. This treatment appears to be a safe and effective technique, although longer follow-up is needed to confirm durability. This modality may prove to be a viable treatment alternative for TN.
authors.affiliation: Department of Radiation Oncology, Mount Sinai Roosevelt Hospital, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, New York. Electronic address: parikhrr@gmail.com.
authors.forename: Rahul R
authors.initials: RR
authors.lastname: Parikh
authors.affiliation: Department of Neurosurgery, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Goodman
authors.affiliation: Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Ryan
authors.initials: R
authors.lastname: Rhome
authors.affiliation: Department of Radiation Oncology, Mount Sinai Roosevelt Hospital, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Edward
authors.initials: E
authors.lastname: Sudentas
authors.affiliation: Department of Radiation Oncology, Mount Sinai Roosevelt Hospital, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Frieda
authors.initials: F
authors.lastname: Trichter
authors.affiliation: Department of Radiation Oncology, Moffitt Cancer Center and Research Institute, Tampa, Florida.
authors.forename: Louis B
authors.initials: LB
authors.lastname: Harrison
authors.affiliation: Department of Radiation Oncology, Mount Sinai Roosevelt Hospital, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Walter
authors.initials: W
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010315:Particle Accelerators; D063868:Patient Outcome Assessment; D011446:Prospective Studies; D016634:Radiosurgery; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000473:pathology / Q000601:surgery*