title: Early results of stand-alone anterior lumbar interbody fusion in iatrogenic spondylolisthesis patients.
abstract: BACKGROUND
  Iatrogenic spondylolisthesis is a challenging condition for spinal surgeons. Posterior surgery in these cases is complicated by poor anatomical landmarks, scar tissue adhesion of muscle and dural structures and difficult access to the intervertebral disc. Anterior interbody fusion provides an alternative treatment method, allowing indirect foraminal decompression, reliable disc clearance and implantation of large surface area implants.
  
  
  METHODS
  A retrospective chart review of patients with iatrogenic spondylolisthesis including pre- and post-operative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores was performed. Imaging criteria were pelvic incidence, overall lumbar lordosis and segmental lordosis. In addition, the fusion rate was investigated after 6 months.
  
  
  RESULTS
  Six consecutive patients treated between 2008 and 2011 (4 female, 2 male, mean age 61 ± 7.1 years) were identified. The initially performed surgeries included decompression with or without discectomy; posterior instrumented and non-instrumented fusion. The olisthetic level was in all cases at the decompressed level. All patients were revised with stand-alone anterior interbody fusion devices at the olisthetic level filled with BMP 2. Average ODI dropped from 49 ± 11 % pre-operatively to 26.0 ± 4.0 at 24 months follow-up. VAS average dropped from 7 ± 1 to 2 ± 0. Mean total lordosis of 39.8 ± 2.8° increased to 48.5 ± 4.9° at pelvic incidences of 48.8 ± 6.8° pre-operatively. Mean segmental lordosis at L4/5 improved from 10.5 ± 6.7° to 19.0 ± 4.9° at 24 months. Mean segmental lordosis in L5/S1 increased from 15.1 ± 7.4° to 23.2 ± 5.6°. Cage subsidence due to severe osteoporosis occurred in one case after 5 months, and hence there was no further follow-up. Fusion was confirmed in all other patients.
  
  
  CONCLUSIONS
  Anterior interbody fusion offers good stabilisation and restoration of lordosis in iatrogenic spondylolisthesis and avoids the well-known problems associated with reentering the spinal canal for revision fusions. In this group, ODI and VAS scores were improved.
authors.affiliation: The Centre for Spinal Studies and Surgery, Queens Medical Centre, Nottingham University Hospitals NHS Trust, Derby Road, Nottingham, NG7 2UH, UK, matthias.a.koenig@gmail.com.
authors.forename: M A
authors.initials: MA
authors.lastname: König
authors.forename: F V
authors.initials: FV
authors.lastname: Ebrahimi
authors.forename: A
authors.initials: A
authors.lastname: Nitulescu
authors.forename: E
authors.initials: E
authors.lastname: Behrbalk
authors.forename: B M
authors.initials: BM
authors.lastname: Boszczyk
mesh_terms: D000368:Aged; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage; D019299:Decompression, Surgical / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000209:etiology; D006801:Humans; D007049:Iatrogenic Disease; D008141:Lordosis / Q000209:etiology / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000209:etiology; D011184:Postoperative Period; D019736:Prostheses and Implants / Q000009:adverse effects; D012086:Reoperation; D012189:Retrospective Studies; D016879:Salvage Therapy / Q000379:methods*; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D013168:Spondylolisthesis / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2
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