Study design: This retrospective clinical study evaluates complications occurring during or immediately after surgery of posterior cervical plating.
Objectives: The present study quantifies risks associated with posterior cervical plating using lateral mass screw fixation. The observed clinical complications are compared with theoretical risks previously studied in cadavers. Unanticipated complications are identified.
Summary of background data: There are many reports that describe posterior cervical plating and attempt to describe the indications for using this type of fixation, but few studies have discussed the clinical complications incurred by application of these plates and screws.
Methods: Seventy-eight consecutive patients whose treatment included posterior cervical lateral mass plating were independently reviewed to identify associated complications. The average patient age was 52.9 years, and the average follow-up period was 2 years (range, 10-47 months). Multiple indications for surgery were present, but complex reconstructive procedures were required in 70.5% of cases. Complication rates were calculated as either a percentage of the number of screws inserted or as a percentage of the number of cases performed or both.
Results: Six hundred fifty-four screws were inserted--an average of 8.4 screws per patient. Complication rates as a function of the number of screws inserted included nerve root injury, 0.6%; facet violations, 0.2%; vertebral artery injury, 0%; broken screw, 0.3%; screw avulsion, 0.2%; and screw loosening 1.1%. Complications as a percentage of the number of cases performed included spinal cord injury, 2.6%; iatrogenic foraminal stenosis, 2.6%; broken plate, 1.3%; lost reduction, 2.6%; adjacent segment degeneration, 3.8%; infection, 1.3%; and pseudoarthrosis, 1.4%.
Conclusions: Cadaveric work has predicted certain anatomic complication rates associated with lateral mass screw insertion. This study finds the risk of lateral mass screw insertion to be considerably less than predicted in vitro. The present study reports other complications that were not predicted in laboratory studies.