351 - Congenital Cervical Stenosis and Pseudoarthrosis Following Anterior Ce...

#351 Congenital Cervical Stenosis and Pseudoarthrosis Following Anterior Cervical Procedure

Cervical Therapies and Outcomes

Poster Presented by: J. Belding

Author(s):

J. Belding (1)
H. Bohlman (1)
J.D. Eubanks (1)

(1) University Hospitals of Cleveland, Orthopedics, Cleveland, OH, USA

Abstract

Introduction: Pseudoarthrosis is a common complication following anterior cervical fusion procedures. The incidence has been reported from 0-20% for single level fusions and up to 50% in multilevel fusions. Most studies suggest that it has a poor prognostic effect on patient outcome and surgical success, and host factors such as smoking and sagittal alignment influence its occurrence.

Congenital stenosis has been established as an important risk factor in the development of myelopathy. Further, MRI studies have suggested that congenitally stenotic spines have greater pathological changes in the intervertebral discs and cord compression than spines with a normal spinal canal.

The current study hypothesized that patients with congenital stenosis would have an increased prevalence of pseudoarthrosis after anterior arthrodesis than patients with normal canal diameters.

Methods: A retrospective review was performed on 169 patients undergoing a one to four level anterior cervical decompression and fusion by a single surgeon. Radiographs were evaluated for bony congenital stenosis by measuring the space available for the cord (SAC) and the Pavlov Ratio (PAV), using the stenosis parameters described by Kang et al. Radiographs were evaluated postoperatively and defined as having a pseudoarthrosis if there was presence of a radiolucent gap between the graft and the vertebral body, a lack of continuing bridging bone, or more than 2mm of motion between the spinous process at the operated segment level on flexion-extension views. Clinical outcome scores were graded on the Robinson and Odom criteria. Statistical analysis was performed using chi square tests comparing the incidence of pseudoarthrosis among patients with and without congenital stenosis.

Results: Pseudoarthrosis was observed in 30 pts (17.75%). The overall rate of congenital cervical stenosis was 24.2% (41 pts). The study included 72 men (43%) and 97 women (57%). The average age of the pt was 52.4. The mean follow up length was 51.9 months (up to 263 months). There were 54 one level fusions, 68 two level fusions, 36 three level fusions and 11 four level fusions. Pseudoarthrosis development was not found to be statistically associated with congenital stenosis (p = 0.1604). The presence of myelopathy on initial presentation was also not statiscally associated with the development of pseudoarthrosis. There was also no association between congenital stenosis and the need for reoperation for pseudoarthrosis. Overall, clinical results demonstrated excellent or good Robinson scores in 79.7% of patients, whereas excellent or good Odom scores were reported in 82.7% of patients.

Conclusions: Congenital stenosis appears in 24.2% of patients undergoing anterior cervical decompression and fusion. Psuedoarthrosis is a common complication of this procedure occurring in 17.75% of this patient population. Bony congenital stenosis does not appear to be a predictor of development of pseudoarthrosis based on this study. Pseudoarthrosis is more likely related to other host factors, such as smoking and sagittal alignment, or surgical technique than to the presence of a congenitally narrowed spinal canal.