title: Stereotactic biopsy of brain stem masses: Decision analysis and literature review.
abstract: BACKGROUND
  Adult brain stem tumors are rare, and diverse pathology can be found in this location. Stereotactic biopsy of lesions in the brain stem has been performed since the 1960s with high diagnostic and low complication rates. Advances in imaging technology have raised questions regarding the utility of biopsy. We perform decision analysis to aid clinicians in their approach to management of adult brain stem lesions.
  
  
  METHODS
  A structured literature search revealed 20 publications with 457 patients who had undergone brain stem lesion biopsy. These publications were reviewed to determine diagnostic rates and the incidence of complications. Standard decision analytic techniques were applied to the case of a virtual adult patient with a lesion in the brain stem.
  
  
  RESULTS
  A 1-way sensitivity analysis revealed the likelihood that the preoperative diagnosis was correct and the rate at which incorrect treatment was based on faulty empirical diagnosis as the 2 factors with the greatest effects on patient outcome. The diagnostic rate and complication rate of biopsy, within the ranges reported in the literature, had lesser effects. A threshold analysis was constructed to compare outcomes from stereotactic biopsy vs empiric therapy for a brain stem lesion. The probability that the preoperative diagnosis is correct is plotted vs the probability that empirical treatment based on an incorrect diagnosis will have adverse effect.
  
  
  CONCLUSIONS
  Management of lesions in the adult brain stem requires careful consideration of multiple preoperative factors including clinical and radiographic diagnostic certainty, consequences of empiric therapy, and the surgeon's complication rate.
authors.affiliation: Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA. uzmasam@yahoo.com
authors.forename: Uzma
authors.initials: U
authors.lastname: Samadani
authors.forename: Sherman
authors.initials: S
authors.lastname: Stein
authors.forename: Gul
authors.initials: G
authors.lastname: Moonis
authors.forename: Seema S
authors.initials: SS
authors.lastname: Sonnad
authors.forename: Pia
authors.initials: P
authors.lastname: Bonura
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Judy
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001706:Biopsy / Q000592:standards* / Q000706:statistics & numerical data; D001933:Brain Stem / Q000473:pathology / Q000601:surgery*; D020295:Brain Stem Neoplasms / Q000175:diagnosis*; D003661:Decision Support Techniques; D003663:Decision Trees; D003951:Diagnostic Errors / Q000517:prevention & control* / Q000706:statistics & numerical data; D003952:Diagnostic Imaging / Q000592:standards / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000592:standards / Q000706:statistics & numerical data; D018570:Risk Assessment; D013238:Stereotaxic Techniques / Q000592:standards* / Q000706:statistics & numerical data; D016896:Treatment Outcome