title: PSO without neuromonitoring: analysis of peri-op complication rate after lumbar pedicle subtraction osteotomy in adults.
abstract: A decompensated sagittal imbalance has been associated with worsening health-related quality of life outcomes and increasing pain. Significant improvement in sagittal balance can be achieved using a pedicle subtraction osteotomy (PSO); however, this procedure has a high complication profile. A lumbar PSO has the advantages of direct visualization of all neural structures and safer retraction of the thecal sac. Sacrificing neuromonitoring may reduce anaesthesia time and lead to improved cost effectiveness of the surgery. However, there are no studies analyzing the complication rate of lumbar PSO without the use of neuromonitoring. We hypothesize that the neurologic complication rate remains comparable to published studies even without the use of intraoperative neuromonitoring.
  
  
  
  The medical records of all patients of a single institution who received a lumbar PSO for sagittal imbalance between July 2012 and June 2014 were retrospectively analyzed. All surgeries were performed by the first author and without the use of intraoperative neuromonitoring. We analyzed the 30-day complication rate.
  
  
  
  Twenty-two patients were included in this study. The average age at surgery was 67 years. 16 patients had at least one previous lumbar surgery. The average fusion length was seven segments. All patients were instrumented to the sacrum and 19 patients additionally received spinopelvic instrumentation. The average amount of focal correction was 28°. The average surgical time was 362 min and blood loss was 2302 mL. A total of eight patients with complications were identified. There was a new neurologic postoperative deficit in two patients presenting as a foot drop. Five patients had an unplanned revision surgery.
  
  
  
  Historically, PSOs are associated with a high surgical complication rate and our results show comparable outcomes and complications to those previously reported. In our series, the absence of neuromonitoring in lumbar PSOs does not appear to increase the risk of neurological injury.
authors.affiliation: Eifelklinik St. Brigida, Zentrum für Orthopädische Chirurgie, Kammerbruchstr. 8, 52152, Simmerath, Germany. pertrobisch@gmail.com.
authors.forename: Per D
authors.initials: PD
authors.lastname: Trobisch
authors.affiliation: Department of Neurosurgery, Tufts Medical Center, 800 Washington Street, Box 178, Boston, MA, 02111, USA.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Hwang
authors.affiliation: Orthopädische Klinik, Universitätsklinik Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Drange
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000453:epidemiology*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D012189:Retrospective Studies
keywords: Complication; Kyphosis; Neuromonitoring; Pedicle subtraction osteotomy; Sagittal imbalance; Scoliosis