Preoperative Imaging Predictors of Postoperative C5 Palsy: A Comparative Study of MRI and Radiographic Imaging Modalities

Retrospective matched cohort study. To evaluate and compare the predictive value of different preoperative imaging measurements and modalities for postoperative C5P. C5 palsy (C5P) is a debilitating complication following cervical spine surgery with unpredictable but typically favorable recovery. While research has explored preoperative radiographic measurements in predicting C5P development, their findings remain inconclusive. Adult patients who underwent anterior cervical discectomy and fusion (ACDF) or posterior cervical decompression and fusion (PCDF) from 2010 to 2023 with available preoperative imaging (MRI or radiographs) and subsequently developed a C5P were matched 1:3 to control patients without C5P. Demographic/surgical/outcome data were collected. Preoperative radiographic measurements included C2-7 Cobb angle, sagittal vertical axis, C2 tilt, C2 and T1 slope, and Pavlov-Torg ratio/stenosis. MRI measurements included anteroposterior canal diameter, bilateral foraminal diameter, bilateral cord-lamina angle, bilateral nerve root diameter, cord/canal cross-sectional area, and stenosis based on Kim grading system. Statistical analysis was conducted with alpha set at 0.05. Sixty-three patients with postoperative C5P and accessible preoperative radiographs were matched with 189 controls. Among the 63 patients with C5P, 42 patients with accessible MRI images were matched to an additional 126 controls. Both cohorts demonstrated similar demographic/surgical variables between C5P and control patients. Among the radiograph cohort, C5P patients had a greater preoperative C2-7 Cobb angle (11.4° vs. 6.39°; P =0.001). All other measurements were similar between patients with C5P and no C5P. Among the MRI cohort, C5P patients had similar measurements as controls. Both MRI and radiographs demonstrated poor predictive power with the highest area under the curve being 0.636 (C2-7 Cobb angle). Neither preoperative radiographic nor MRI measurements demonstrated predictive power for postoperative C5P in this study thereby highlighting the need for additional strategies to preoperatively identify patients at risk for C5P.