title: Direct repair of spondylolysis without spondylolisthesis, using a rod-screw construct and bone grafting of the pars defect.
abstract: METHODS
  A retrospective study of patient outcome after pars repair using an original technique in patients with spondylolysis without spondylolisthesis and degenerative disk disease.
  
  
  OBJECTIVE
  To assess the results of a new technique of internal fixation that avoids penetration of the spinal canal, temporary fixation of the lumbosacral junction, and postoperative bracing owing to stable instrumentation consisting of pedicle screws and a V-shaped rod resting against the inferior aspect on the spinous process and the posterior aspects of the laminas.
  
  
  BACKGROUND
  Previously described techniques for direct repair of a pars defect often require postoperative bracing and can require intracanal penetration of wires or hooks; screws passing directly through the defect, thereby lessening the bone surface available for bone grafting; and temporary fixation of the lumbosacral junction with a plate that must be removed.
  
  
  METHODS
  Patients with painful pars defect not responding to conservative therapy and interfering with everyday life, sports, or work were considered to be eligible for direct repair of the spondylolysis rather than lumbosacral fusion, if there was no associated degenerative disk disease or spondylolisthesis. The surgical technique involves placement of screws on the pedicles of the involved vertebra and the fixation of the loose posterior arch with a solid rod bent in a V shape, taking purchase on the spinous process and laminas. A bone graft is placed under compression in the pars defect before the rod-screw construct is tightened.
  
  
  RESULTS
  The first 10 patients who underwent this technique had an average follow-up of 35 months (range, 7 months to 5.3 years); mean age at operation was 26 years (range, 16-48 years). Six patients had an excellent result, returned to normal everyday life and work, and participated in sports when desired. The outcome in one patient was rated good and in one, fair. The procedure in one was considered a failure, although bone fusion seemed to have been obtained. Seven patients would recommend the operation, one would hesitate. No complications were encountered because of the specific design of the construct.
  
  
  CONCLUSIONS
  This new technique offers the advantage of being easy and fast, it can be performed using a great number of available spinal instrumentations using rods and pedicle screws. There is no violation of the neural canal except in the case of a misplacement of pedicle screws. No postoperative brace was used, return to everyday life avoiding low back stress was immediate, and return to work or sports was possible 3 to 6 months after the procedure. This technique seems safe and effective but needs careful selection of patients, as do all other techniques for direct repair of pars interarticularis.
authors.affiliation: Orthopaedic Department, University Hospital (CHU du Sart-Tilman), Liège, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Gillet
authors.forename: M
authors.initials: M
authors.lastname: Petit
mesh_terms: D000293:Adolescent; D000328:Adult; D001863:Bone Screws; D016025:Bone Transplantation; D005260:Female; D006801:Humans; D007085:Ilium / Q000637:transplantation*; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009989:Orthotic Devices; D011859:Radiography; D012189:Retrospective Studies; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013169:Spondylolysis / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome