title: Sacral dome resection and single-stage posterior reduction in the treatment of high-grade high dysplastic spondylolisthesis in adolescents and young adults.
abstract: OBJECTIVE
  The description of the operation technique and retrospective review of 15 consecutive patients who were treated by posterior sacral dome resection and single-stage reduction with pedicle screw fixation for high-grade, high-dysplastic spondylolisthesis.
  
  
  METHODS
  All the patients had high-grade, high-dysplastic spondylolisthesis L5 and were treated by posterior sacral dome resection and posterior single-stage reduction from L4-S1. The average age at the time of surgery was 17.3 (11-28) years. The average follow-up time is 5.5 (2-11.6) years. Clinical and radiological data were retrospectively reviewed.
  
  
  RESULTS
  Spondylolisthesis was reduced from average 99% preoperative to 29% at the last follow-up. L5 incidence improved from 74° to 56°, the lumbosacral angle improved from 15° kyphosis to 6° lordosis, lumbar lordosis decreased from 69° to 53° from preoperative to the last follow-up. While pelvic incidence of 77° remained unchanged, sacral slope decreased from 51° to 46° and pelvic tilt increased from 25° to 30°. Clinical outcome was subjectively rated to be much better than before surgery by 14 out of 15 patients. Four out of 15 patients had temporary sensory impairment of the L5 nerve root which resolved completely within 12 weeks. There were no permanent neurological complications or no pseudarthrosis.
  
  
  CONCLUSIONS
  The sacral dome resection is a shortening osteotomy of the lumbosacral spine which allows a single-stage reduction of L5 without lengthening of lumbosacral region in high-grade spondylolisthesis, which helps to avoid neurological complications. This is a safe surgical technique resulting in a good multidimensional deformity correction and restoration of spino-pelvic alignment towards normal values with a satisfactory clinical outcome.
authors.affiliation: Balgrist Clinic, Department of Orthopaedic Surgery, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland. kan.min@balgrist.ch
authors.forename: Kan
authors.initials: K
authors.lastname: Min
authors.forename: Thomas
authors.initials: T
authors.lastname: Liebscher
authors.forename: Dominique
authors.initials: D
authors.lastname: Rothenfluh
mesh_terms: D000293:Adolescent; D000328:Adult; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000601:surgery; D001863:Bone Screws; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods*; D010027:Osteotomy / Q000295:instrumentation / Q000379:methods*; D011859:Radiography; D012189:Retrospective Studies; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery*; D012720:Severity of Illness Index; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult