title: Lateral mass screw complications: analysis of 1662 screws.
abstract: METHODS
  Retrospective, consecutive patient series.
  
  
  OBJECTIVE
  To quantify the risks and the complications associated with screw fixation devices of the cervical spine.
  
  
  BACKGROUND
  The usefulness of lateral mass internal fixation has been well documented in the clinical setting. However, there is a paucity of studies examining the complications associated with these devices in a degenerative clinical setting.
  
  
  METHODS
  From 1999 to 2007, 225 consecutive patients underwent posterior cervical fixation using a screw-plate and polyaxial screw-rod implant systems. There were 105 women and 120 men (age range: 45 to 84 y; mean, 68 y). In all patients, the surgical indication was cervical spondylosis with myelopathy. Mean follow-up interval was 18 months (range: 12 to 72 mo). Screw position was evaluated by computed tomography scanning postoperatively in all patients. Clinical and radiographic outcome was assessed at each visit after surgery.
  
  
  RESULTS
  Intraoperative complications include fracture of lateral mass in 27 screws placement and nerve irritation in 3 bicortical screws. Early complications include hematoma formation in 2 cases and C5 root palsy in 5 cases after spinal canal decompression. Late complications include pseudarthrosis in 6 cases and screw pull-out in 3 cases. There were no cases of spinal cord or vertebral artery injury, infections, deaths, or adjacent segment disease. All patients had radiographic union, and no patient developed mechanical implant failure requiring removal of instrumentation. Reoperation was required in 14 (6.2%) cases because of nerve injury, hematoma formation, pseudarthrosis, and screw pull-out.
  
  
  CONCLUSIONS
  Our clinical findings indicate that lateral mass fixation can be used safely with minimal complications and low rate of morbidity for cervical myelopathy treatment.
authors.affiliation: Department of Orthopaedics, Crete University, Medical School, Herakleion, Athens, Greece.
authors.forename: Pavlos
authors.initials: P
authors.lastname: Katonis
authors.forename: Stamatios A
authors.initials: SA
authors.lastname: Papadakis
authors.forename: Spyros
authors.initials: S
authors.lastname: Galanakos
authors.forename: Ditran
authors.initials: D
authors.lastname: Paskou
authors.forename: Artan
authors.initials: A
authors.lastname: Bano
authors.forename: George
authors.initials: G
authors.lastname: Sapkas
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Hadjipavlou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001858:Bone Nails / Q000009:adverse effects; D001863:Bone Screws / Q000009:adverse effects*; D002574:Cervical Vertebrae / Q000601:surgery*; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D011859:Radiography; D012189:Retrospective Studies; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery; D013123:Spinal Fusion / Q000009:adverse effects* / Q000295:instrumentation*; D055009:Spondylosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*