Spine - 2026-05-15 - Journal Article; Comparative Study
Preoperative Imaging Predictors of Postoperative C5 Palsy: A Comparative Study of MRI and Radiographic Imaging Modalities.
Dalton J, Huang R, Carter M, Oris RJ, Baidya J, Mathew J, Narayanan R, Kim A, Fras S, Blas J, LaBarbiera A, Ruiz M, Uvarov E, Patel K, Kurd MF, Kaye ID, Canseco JA, Hilibrand AS, Vaccaro AR, Schroeder GD, Kepler CK
Topics
Key Takeaway
Preoperative C2-7 Cobb angle was the only imaging predictor of C5 palsy (11.4° vs. 6.39°, p=0.001), yet its AUC of 0.636 renders both MRI and radiographic measurements clinically non-predictive.
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Summary
This retrospective matched cohort study evaluated whether preoperative radiographic and MRI measurements could predict postoperative C5 palsy in patients undergoing ACDF or PCDF from 2010–2023. C5P patients had a greater preoperative C2-7 Cobb angle than controls (11.4° vs. 6.39°, p=0.001), but all other radiographic and MRI parameters—including foraminal diameter, cord-lamina angle, canal diameter, and Kim grading stenosis—were equivalent between groups. The highest AUC across all measurements was 0.636, indicating poor discriminative ability for any single imaging metric.
Key Limitation
The retrospective design with incomplete MRI availability for one-third of C5P cases risks underrepresentation of the most severely affected patients and limits the validity of the MRI cohort findings.
Original Abstract
STUDY DESIGN
Retrospective matched cohort study.
OBJECTIVE
To evaluate and compare the predictive value of different preoperative imaging measurements and modalities for postoperative C5P.
SUMMARY OF BACKGROUND
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.
MATERIALS AND METHODS
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.
RESULTS
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).
CONCLUSION
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.