Radiographic Measures of Spinal Alignment Are Not Predictive of the Development of C5 Palsy Following Anterior Cervical Discectomy and Fusion Surgery

Abstract

Background: Postoperative C5 palsy is a common complication following cervical decompression, occurring more frequently after posterior-based procedures. It has been theorized that this is the result of C5 nerve stretch resulting from spinal cord drift with these procedures. As such, it is thought to be less common after anterior cervical decompression and fusion (ACDF). However, no consensus has been reached on its true etiology. The purpose of this study is to assess the rate of C5 palsy following ACDF and to determine whether any radiographic or demographic parameters were predictive of its development.

Methods: Two hundred and twenty-six patients who received ACDF between September 2015 and September 2016 were reviewed, and 122 were included in the final analysis. Patient demographic, surgical, and radiographic data were analyzed, including preoperative and postoperative radiographic and motor examination results. The Mann-Whitney U test was used to compare continuous variables between independent groups, and Fisher's exact test was used to compare categorical variables between groups.

Results: Seven patients developed a C5 palsy in the postoperative period, an incidence rate of 5.7%. Among the radiographic parameters evaluated, there were no statistically significant differences between the C5 palsy and nonpalsy groups. Additionally, there were no statistically significant differences in age, patient sex, or numbers of vertebral levels fused between groups.

Conclusions: Ultimately, we did not identify any statistically significant demographic or radiographic predictive factors for the development of C5 palsy following ACDF surgery.

Level of evidence: 3.

Keywords: ACDF; C5 palsy; anterial cervical discectomy and fusion; cervical; demographic; orthopedic; palsy; radiographic; spine; surgery.

Figure 1

Algorithm describing patient exclusion criteria for analysis. Out of 226 patients who underwent anterior cervical decompression and fusion, 122 were ultimately included in our analysis.

Figure 2

The C2–C7 Cobb angle is defined by the angle made by the intersection of 2 lines, 1 going through the inferior endplate of C2 and the other going through the inferior end plate of C7 (A). The local Cobb angle (B) is defined by the angle made by 2 lines, 1 line going through the superior end plate of the top vertebral level and the other going through the inferior end plate of the bottom vertebral level being considered in the anterior cervical decompression and fusion. For both the C2–C7 and the local Cobb angle, lordotic angles are considered to be positive. The sagittal vertical axis (C) is the length of a perpendicular line drawn between a line drawn vertically down from the center of the dens and a line drawn vertically down from the inferior posterior end plate of C7. Vertebral segment height (D) is defined as the length of a line between the superior posterior end plate of the superior vertebrae and the inferior posterior end plate of the inferior vertebrae being considered. The C2–C7 cervical height (E) is the length of a line drawn between the inferior posterior end plate of C2 to the inferior posterior end plate of C7.