title: Microvascular decompression after gamma knife surgery for trigeminal neuralgia: intraoperative findings and treatment outcomes.
abstract: OBJECTIVE
  The authors sought to determine whether the results of trigeminal microvascular decompression (MVD) are influenced by prior gamma knife surgery (GKS).
  
  
  METHODS
  Gamma knife surgery is an established procedure for treating medically intractable trigeminal neuralgia but failures do occur. The authors assessed six patients (two men and four women; mean age 52 years) who experienced pain recurrence after GKS and elected to undergo trigeminal MVD via retrosigmoid craniotomy. Three patients underwent a single GKS to a maximal dose of 80 Gy, whereas three others underwent a second GKS to total of 120 to 135 Gy. At surgery, none of the six patients demonstrated excess arachnoid thickening, grossly apparent changes in the nerve itself, or any other tissue alterations that made successful mobilization of a blood vessel from the trigeminal root entry zone technically more difficult. A single individual had a small atherosclerotic plaque in the superior cerebellar artery near its contact point with the trigeminal nerve. Follow up at a mean of 25.4 months (range 7.5-42 months) indicated that five patients were pain free. One patient had improved but still relied on medications for pain control.
  
  
  CONCLUSIONS
  In the authors' experience, trigeminal MVD can be performed without added difficulty in patients who have previously undergone GKS. The success rates seem similar to those normally associated with MVD. Patients who elect the less invasive option of GKS can be assured that trigeminal MVD remains a viable alternative at a later date if further surgery is required.
authors.affiliation: Division of Neurological Surgery and Pediatric Oncology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013, USA. neuropub@chw.edu
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Shetter
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Zabramski
authors.forename: Burton L
authors.initials: BL
authors.lastname: Speiser
mesh_terms: D000328:Adult; D000368:Aged; D003399:Craniotomy; D019299:Decompression, Surgical / Q000379:methods*; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D011829:Radiation Dosage; D016634:Radiosurgery / Q000295:instrumentation*; D014277:Trigeminal Neuralgia / Q000601:surgery*