title: Frameless linac-based stereotactic radiosurgery treatment for SUNCT syndrome targeting the trigeminal nerve and sphenopalatine ganglion.
abstract: BACKGROUND
  The short-lasting unilateral neuralgiform headache associated with conjunctival injection and tearing or SUNCT syndrome was first described in the 1970s. This paper is the first in the literature that describes the successful use of stereotactic radiosurgery (SRS) using a non-invasive frameless technique, targeting both the trigeminal nerve and the sphenopalatine ganglion in the management of intractable SUNCT. We also discuss the role of selecting peripheral targets in the management of this rare headache syndrome.
  
  
  METHODS
  Among patients treated for functional pain disorders in our radiosurgery unit using the frameless technique since August 2011, one patient with symptoms matching the International Classification of Headache Disorders-2 (ICHD-II) criteria of SUNCT syndrome was identified. The multi-disciplinary case records of this patient were retrospectively reviewed and reported.
  
  
  RESULTS
  Our patient had symptoms resembling the ICHD-II diagnostic criteria of SUNCT, which was refractory to medical treatment. Ninety Gy was delivered to the trigeminal root entry zone and 80 Gy was delivered to the sphenopalatine ganglion. At 16 months' follow-up, she was pain free with minimal side effects.
  
  
  CONCLUSIONS
  Frameless linear accelerator (linac)-based SRS targeting the trigeminal nerve and sphenopalatine ganglion remained successful in our patient at 16 months. Longer follow-up and further experience will determine the efficacy and safety of this approach. We suggest that frameless SRS is a convenient and attractive non-invasive option for patients with medically refractory SUNCT.
authors.affiliation: Department of Radiation Oncology, National Cancer Centre Singapore, Singapore.
authors.forename: Daniel Y H
authors.initials: DY
authors.lastname: Tan
authors.forename: Eu Tiong
authors.initials: ET
authors.lastname: Chua
authors.forename: Kim Bock
authors.initials: KB
authors.lastname: Ng
authors.forename: Kwang Ping
authors.initials: KP
authors.lastname: Chan
authors.forename: John
authors.initials: J
authors.lastname: Thomas
mesh_terms: D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D016634:Radiosurgery / Q000379:methods*; D050798:SUNCT Syndrome / Q000601:surgery*; D014276:Trigeminal Nerve / Q000601:surgery
keywords: SUNCT (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing); frameless stereotactic radiosurgery (SRS); radiosurgery; sphenopalatine ganglion; trigeminal cephalalgia; trigeminal nerve