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Lateral Mass Screw Complications: Analysis of 1662 Screws

Katonis, Pavlos MD*; Papadakis, Stamatios A. MD; Galanakos, Spyros MD; Paskou, Ditran MD*; Bano, Artan MD*; Sapkas, George MD; Hadjipavlou, Alexander G. MD*

doi: 10.1097/BSD.0b013e3182024c06
Original Articles

Study Design Retrospective, consecutive patient series.

Objective To quantify the risks and the complications associated with screw fixation devices of the cervical spine.

Summary of Background Data 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.

*Department of Orthopaedics, Crete University, Medical School, Herakleion

D' Department of Orthopaedics, “KAT” General Hospital, Kifissia

A' Department of Orthopaedics, Athens University, Medical School, Athens, Greece

No funds have been received for this study.

The authors declare no conflict of interest.

Reprints: Stamatios A. Papadakis, MD, 28th Octovriou Street, 54, 15236 North Penteli, Greece (e-mail:

Received December 2, 2009

Accepted September 24, 2010

© 2011 Lippincott Williams & Wilkins, Inc.