title: Pedicle subtraction osteotomy.
abstract: OBJECTIVE
  Pedicle subtraction osteotomy (PSO) is an effective tool for the correction of fixed sagittal plane deformity. However, there is potentially significant perioperative morbidity associated with this technique. We report our perioperative morbidity rate in recently performed PSO cases treated with our present surgical, anesthetic, and monitoring techniques and discuss complication-avoidance strategies.
  
  
  METHODS
  We conducted a retrospective study of 10 patients (mean age, 56 yr; range, 7-77 yr) undergoing thoracolumbar PSO at a single institution in the past 3 years. Two patients underwent PSO at T12, seven patients underwent PSO at L3, and one patient underwent PSO at L2. Eight of the patients had undergone at least one previous spine surgery in the region of the PSO, and nine of the patients had comorbidities that increased their surgical risk stratification. We identified all causes of perioperative morbidity.
  
  
  RESULTS
  We classified perioperative complications into two categories: intraoperative and early postoperative. Intraoperative complications included dural tears in two patients, cardiovascular instability in one patient, and coagulopathy in two patients. Early postoperative complications included neurological deficit (one patient), wound infection (two patients), urinary tract infection (one patient), and delirium (two patients). All patients recovered fully from these complications. There was no mortality in this series.
  
  
  CONCLUSIONS
  In this series, most patients undergoing PSO had multiple previous spine surgeries and comorbidities. The risk of perioperative morbidity for revision cases undergoing PSO was in excess of 50%. We discuss complication-avoidance strategies.
authors.affiliation: Department of Neurosurgery, University of California, San Francisco, San Francisco, California 94143, USA. vmum@aol.com
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Mummaneni
authors.forename: Sanjay S
authors.initials: SS
authors.lastname: Dhall
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Ondra
authors.forename: Valli P
authors.initials: VP
authors.lastname: Mummaneni
authors.forename: Sigurd
authors.initials: S
authors.lastname: Berven
mesh_terms: D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000295:instrumentation / Q000379:methods*; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*