title: Variability of outcome after lumbar disc surgery.
abstract: METHODS
  A prospective, consecutive study of patients' outcome at three subsequent follow-up times after lumbar disc surgery.
  
  
  OBJECTIVE
  To evaluate how consistent outcome remained in a group of patients after lumbar disc surgery.
  
  
  BACKGROUND
  Despite similar results concerning the overall outcome, results in most studies show different prognostic factors for lumbar disc surgery at different follow-up times. A reason for this observation could be that patients shift to a different outcome group during the observation period.
  
  
  METHODS
  Before surgery and at the three follow-ups (3, 12, and 28 months after surgery) the Low Back Outcome Score was calculated. Groups with favorable and unfavorable outcome were determined after each follow-up according to the scores.
  
  
  RESULTS
  Ninety-eight patients were studied. Forty percent showed an unstable outcome at different follow-up times. For each follow-up, three prognostic factors were determined. No prognostic factor showed significance at all follow-up examinations.
  
  
  CONCLUSIONS
  Patients whose outcome after lumbar disc surgery does not remain stable present a major problem in the calculation of prognostic factors.
authors.affiliation: Department of Neurosurgery, University of Regensburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Woertgen
authors.forename: R D
authors.initials: RD
authors.lastname: Rothoerl
authors.forename: K
authors.initials: K
authors.lastname: Breme
authors.forename: J
authors.initials: J
authors.lastname: Altmeppen
authors.forename: M
authors.initials: M
authors.lastname: Holzschuh
authors.forename: A
authors.initials: A
authors.lastname: Brawanski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017586:Diskectomy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000601:surgery*; D017116:Low Back Pain / Q000209:etiology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017060:Patient Satisfaction; D011379:Prognosis; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome