title: Minimally invasive tubular microdiscectomy for recurrent lumbar disc herniation.
abstract: OBJECTIVE
  The aim of the study was to investigate the safety and efficacy of minimally invasive tubular microdiscectomy for the treatment of recurrent lumbar disc herniation (LDH). As opposed to endoscopic techniques, namely microendoscopic and endoscopic transforaminal discectomy, this microscopically assisted technique has never been used for the treatment of recurrent LDH.
  
  
  METHODS
  Thirty consecutive patients who underwent minimally invasive tubular microdiscectomy for recurrent LDH were included in the study. The preoperative and postoperative visual analog scale (VAS) scores for pain, the clinical outcome according to modified Macnab criteria, and complications were analyzed retrospectively. The minimum follow-up was 1.5 years. Student t-test with paired samples was used for the statistical comparison of pre- and postoperative VAS scores. A p value < 0.05 was considered to be statistically significant.
  
  
  RESULTS
  The mean operating time was 90 ± 35 minutes. The VAS score for leg pain was significantly reduced from 5.9 ± 2.1 preoperatively to 1.7 ± 1.3 postoperatively (p < 0.001). The overall success rate (excellent or good outcome according to Macnab criteria) was 90%. Incidental durotomy occurred in 5 patients (16.7%) without neurological consequences, CSF fistula, or negative influence to the clinical outcome. Instability occurred in 2 patients (6.7%).
  
  
  CONCLUSIONS
  The clinical outcome of minimally invasive tubular microdiscectomy is comparable to the reported success rates of other minimally invasive techniques. The dural tear rate is not associated to higher morbidity or worse outcome. The technique is an equally effective and safe treatment option for recurrent LDH.
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hubbe
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Germany.
authors.forename: Pamela
authors.initials: P
authors.lastname: Franco-Jimenez
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Germany.
authors.forename: Jan-Helge
authors.initials: JH
authors.lastname: Klingler
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Germany.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vasilikos
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Scholz
authors.affiliation: Department of Neurosurgery, University Medical Center Freiburg, Germany.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kogias
mesh_terms: D000328:Adult; D000368:Aged; D017586:Diskectomy / Q000379:methods; D004724:Endoscopy / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D010147:Pain Measurement / Q000379:methods; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: ETD = endoscopic transforaminal discectomy; FSP = fibrin sealant patch; LDH = lumbar disc herniation; MED = microendoscopic discectomy; VAS = visual analog scale; complication; lumbar disc herniation; microdiscectomy; minimally invasive; recurrent