title: A proposed plan for personalized radiosurgery in patients with trigeminal neuralgia.
abstract: OBJECTIVE During the last 25 years, more than 100,000 patients worldwide with trigeminal neuralgia (TN) have undergone stereotactic radiosurgery (SRS) with a standard dose of radiation. However, the radiobiological effect of radiation is determined by the amount of energy delivered to the tissue (integral dose [ID] = mean dose × target volume) and is directly associated with the nerve volume. Although the trigeminal nerve volume varies among patients with TN, the clinical impact of this variation in delivered energy is unknown. The objective of this study was to evaluate the effect of delivered ID on the outcome of TN radiosurgery. METHODS The authors evaluated 155 patients with unilateral TN who had undergone SRS as their initial surgical management over a 13-year period. The authors measured the postganglionic ID within the SRS target and retrospectively stratified patients into 3 groups: low (< 1.4 mJ), medium (1.4-2.7 mJ), and high (> 2.7 mJ) ID. Clinical outcomes, which included pain status (scored using the Barrow Neurological Institute Pain Scale) and sensory dysfunction (scored using the Barrow Neurological Institute Numbness Scale), were evaluated at a median follow-up of 71 months. RESULTS Patients who were treated with a medium ID had superior pain relief either with or without medications (p = 0.006). In the medium ID group, the rates of complete pain relief without medications at 1, 3, and 6 years after SRS were 67%, 54%, and 33%, respectively, while the rates in the rest of the cohort were 55%, 36%, and 19%, respectively. Patients given a high ID had a higher rate of post-SRS trigeminal sensory deterioration (p < 0.0001). At 1, 3, and 6 years after SRS, the high ID group had an estimated rate for developing sensory dysfunction of 35%, 45%, and 50%, respectively, while the rates in patients receiving low and medium IDs were 3%, 4%, and 9%, respectively. The optimal clinical outcome (maximum pain relief and minimal trigeminal sensory dysfunction) was obtained in patients who had received a medium ID. CONCLUSIONS With current dose selection methods, nerve volume affects long-term clinical outcomes in patients with TN who have undergone SRS. This study suggests that the prescribed SRS dose should be customized for each TN patient based on the nerve volume.
authors.affiliation: Departments of1Neurosurgery and.
authors.forename: Seyed H
authors.initials: SH
authors.lastname: Mousavi
authors.affiliation: Departments of1Neurosurgery and.
authors.forename: Ajay
authors.initials: A
authors.lastname: Niranjan
authors.affiliation: 3University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Berkcan
authors.initials: B
authors.lastname: Akpinar
authors.affiliation: Departments of1Neurosurgery and.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Monaco
authors.affiliation: 3University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cohen
authors.affiliation: Departments of1Neurosurgery and.|2Radiation Oncology, University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center; and.
authors.forename: Jagdish
authors.initials: J
authors.lastname: Bhatnagar
authors.affiliation: Departments of1Neurosurgery and.
authors.forename: Yue-Fang
authors.initials: YF
authors.lastname: Chang
authors.affiliation: Departments of1Neurosurgery and.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.affiliation: Departments of1Neurosurgery and.
authors.forename: Sakibul
authors.initials: S
authors.lastname: Huq
authors.affiliation: 2Radiation Oncology, University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center; and.
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.affiliation: Departments of1Neurosurgery and.|2Radiation Oncology, University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center; and.
authors.forename: L
authors.initials: L
authors.lastname: Dade Lunsford
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D010146:Pain / Q000209:etiology / Q000601:surgery; D057285:Precision Medicine; D011874:Radiometry; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000150:complications / Q000601:surgery*
keywords: BNI-NS = Barrow Neurological Institute Numbness Scale; BNI-PS = BNI Pain Scale; CI = confidence interval; HR = hazard ratio; ID = integral dose; SRS = stereotactic radiosurgery; TN = trigeminal neuralgia; clinical outcome; integral dose; pain; stereotactic radiosurgery; trigeminal nerve volume; trigeminal neuralgia