Effect of Preoperative Motor Weakness on Postoperative Clinical Outcomes in Patients Undergoing Cervical Disk Replacement.

Study design: This is a retrospective review.

Objective: To examine the effect of preoperative motor weakness on clinical outcomes in patients undergoing cervical disk replacement (CDR).

Summary of background data: Studies examining the effect of preoperative motor weakness on postoperative clinical outcomes in CDR are limited.

Methods: Patient cohorts were based on documented upper-extremity motor weakness on physical exam versus no motor weakness. Demographics, perioperative characteristics, and preoperative patient-reported outcome measures (PROMs) were compared using univariate inferential statistics. PROMs consisted of Visual Analog Pain Scale-Neck (VAS-N), Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), VAS-Arm (VAS-A), 12-Item Short Form (SF-12) Physical Component Score (PCS), Oswestry Neck Disability Index (NDI), and SF-12 Mental Component Score (MCS). Postoperative PROMs were collected at the 6-week, 12-week, 6-month, and final follow-up up to 1-yeartime points, and intercohort minimum clinically important difference (MCID) achievement was compared through multivariable linear logistic regression adjusting for significant differences in preoperative characteristics.

Results: A total of 118 patients formed cohorts based on documented upper-extremity weakness (n=73) versus no weakness (n=45). The average time to postoperative follow-up was 9.7±7.0 mo. The differences in insurance type between the 2 cohorts were significant ( P <0.042). Perioperative diagnosis of foraminal stenosis was significantly more common in the motor weakness cohort ( P <0.013). There were no differences in reported PROMs between cohorts. Patients with motor weakness reported significant MCID achievement for PROMIS-PF at 6-/12-weeks ( P <0.012, P <0.041 respectively), SF-12 PCS at 6-months ( P <0.042), VAS-N at final follow-up ( P <0.021), and NDI at final follow-up ( P <0.013).

Conclusions: CDR patients with preoperative muscle weakness achieved MCID across several PROMs compared with patients without muscle weakness. Patients with motor weakness reported greater improvement in mental health, pain, and disability as early as 6 weeks and up to 1 year after CDR. This information serves to inform physicians that motor weakness may not indicate a negative overall outcome.