title: CyberKnife rhizotomy for facetogenic back pain: a pilot study.
abstract: OBJECTIVE
  By targeting the medial branches of the dorsal rami, radiofrequency ablation and facet joint injections can provide temporary amelioration of facet joint-producing (or facetogenic) back pain. The authors used CyberKnife radiosurgery to denervate affected facet joints with the goal of obtaining a less invasive yet more thorough and durable antinociceptive rhizotomy.
  
  
  METHODS
  Patients with refractory low-back pain, in whom symptoms are temporarily resolved by facet joint injections, were eligible. The patients were required to exhibit positron emission tomography-positive findings at the affected levels. Radiosurgical rhizotomy, targeting the facet joint, was performed in a single session with a marginal prescription dose of 40 Gy and a maximal dose of 60 Gy.
  
  
  RESULTS
  Seven facet joints in 5 patients with presumptive facetogenic back pain underwent CyberKnife lesioning. The median follow-up was 9.8 months (range 3-16 months). The mean planning target volume was 1.7 cm(3) (range 0.9-2.7 cm(3)). A dose of 40 Gy was prescribed to a mean isodose line of 79% (range 75-80%). Within 1 month of radiosurgery, improvement in pain was observed in 3 of the 5 patients with durable responses at 16, 12, and 6 months, respectively, of follow-up. Two patients, after 12 and 3 months of follow-up, have neither improved nor worsened. No patient has experienced acute or late-onset toxicity.
  
  
  CONCLUSIONS
  These preliminary results suggest that CyberKnife radiosurgery could be a safe, effective, and non-invasive alternative to radiofrequency ablation for managing facetogenic back pain. No patient suffered recurrent symptoms after radiosurgery. It is not yet known whether pain relief due to such lesions will be more durable than that produced by alternative procedures. A larger series of patients with long-term follow-up is ongoing.
authors: Department of Neurosurgery, Stanford University School of Medicine, Stanford, California, USA. gordonli@stanford.edu
authors: Gordon
authors: G
authors: Li
authors: Chirag
authors: C
authors: Patil
authors: John R
authors: JR
authors: Adler
authors: Shivanand P
authors: SP
authors: Lad
authors: Scott G
authors: SG
authors: Soltys
authors: Iris C
authors: IC
authors: Gibbs
authors: Laurie
authors: L
authors: Tupper
authors: Maxwell
authors: M
authors: Boakye
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001416:Back Pain / Q000473:pathology / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D016634:Radiosurgery / Q000379:methods*; D019051:Rhizotomy / Q000379:methods*