title: Surgical results and risk factors for recurrence of lumbar disc herniation.
abstract: OBJECTIVE
  Recurrent lumbar disc herniation has been defined as disc herniation at the same level, regardless of ipsilateral or contralateral herniation, with a pain-free interval greater than 6 months. The aim of this study is to analyze outcomes and identify the potential risk factors for recurrent lumbar disc herniation.
  
  
  METHODS
  The authors retrospectively reviewed the cases of 178 patients who underwent open discectomy for single-level lumbar disc herniation. Visual analogue scales and modified Macnab criteria were used to compare the clinical outcomes between the recurrent group and the non-recurrent group. Sex, age, discectomy level, degree of disc degeneration, type of disc herniation, pain-free interval after first-operation, smoking status, and trauma were investigated as potential recurrence risk factors.
  
  
  RESULTS
  Of the 178 patients for whom the authors were able to definitely assess symptomatic recurrence status, 18 patients (10.1%) underwent revision surgery for recurrent disc herniation. The most common level involved was L4-L5 (61%) and the mean period of time to recurrence was 18.7 months (6-61 months). There were 17 cases of ipsilateral herniation and 1 case of contralateral herniation. The types of herniation for which revision surgery was done were protrusion (3 cases), and transligamentous extrusion (14 cases). There were five excellent, eight good, and two fair results.
  
  
  CONCLUSIONS
  Repeated discectomy for recurrent disc herniation produced unsatisfactory outcomes. Factors such as sex, type of disc herniation and traumatic events were found to be significant risk factors.
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Jung Tae
authors.initials: JT
authors.lastname: Oh
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Ki Seok
authors.initials: KS
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Sung Sam
authors.initials: SS
authors.lastname: Jung
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Seung Young
authors.initials: SY
authors.lastname: Chung
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Seong Min
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Moon Sun
authors.initials: MS
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Eulji University College of Medicine, Daejeon, Korea.
authors.forename: Han Kyu
authors.initials: HK
authors.lastname: Kim
keywords: Discectomy; Lumbar vertebrae; Recurrence; Risk factors