Introduction: Previous studies have investigated the relationship between various radiographical parameters and the severity of cervical spondylotic myelopathy (CSM) or improvements in quality of life (QOL). However, no prior study has described the relationship between C2/C3 disc angle and postoperative outcomes for decompression/fusion in CSM patients.
Methods: A retrospective study was conducted among patients undergoing anterior or posterior decompression with fusion for CSM from 2009-2017. Measurements for C2/C3 disc angle, T1 slope, C1/C2 lordosis, C2-C7 lordosis, and C2-C7 SVA were collected from preoperative and postoperative radiographs for each patient. QOL instruments (EQ-5D, PDQ, and PHQ-9) were prospectively collected. The primary outcome measure was QOL minimum clinically important difference (MCID). Multivariate regressions analyses were done for postoperative radiographic measurement and demographics.
Results: 426 procedures were eligible. Demographic data is shown in Table 1.
Of patients who had an increase in C2/C3 disc angle postoperatively, 43% reached MCID for EQ-5D, 31% for PDQ, and 20% for PHQ-9. Of those who had a decrease in C2/C3 disc angle, 49% reached MCID for EQ-5D, 39% for PDQ, and 26% for PHQ-9. Differences in MCID rates were not significant (p=0.6, 0.3, and 0.4, respectively). MCID was not significantly associated with an increase or decrease in the remainder of the radiographic parameters studied (Table 3).
Age, male sex, and BMI each positively predicted postoperative C2/C3 disc angle in the multivariate regression analysis (p=0.00001, 0.002, and 0.0003, respectively). Postoperative C2/C3 disc angle positively predicted improvement in EQ-5D (p=0.04). Postoperative values for the other radiographic parameters did not predict change in QOL (Table 4).
Conclusions: Opposite to our hypothesis, a decrease in C2/C3 disc angle after cervical decompression and fusion was not associated with an improvement in QOL, and even independently predicted a decrease in EQ-5D. Increased age, BMI, and male sex were all significant predictors of higher postoperative C2/C3 disc angle.
Patient Care: Our study is aimed at improving patient care by analyzing postoperative C2-C3 disc angle as a potential predictor of patient outcomes. This would help improve surgical planning. Our demographic analysis helps identify specific groups of patients that are most likely to have higher postoperative measures for C2-C3 angle. This could help spine surgeons better identify appropriate patients for cervical decompression and fusion.
Learning Objectives: By the conclusion of this session, participants should be able to 1) better understand how C2-C3 disc angle is related to postoperative outcomes in patients with CSM, 2) identify certain demographic measures that are associated with postoperative C2-C3 disc angle.