Introduction: Posterior operative approaches have demonstrated clinical benefit for multilevel cervical spondylotic myelopathy (CSM). Prior investigations have independently reported the radiographic and quality of life (QOL) outcomes associated with posterior cervical surgery, but the relationship between radiographic metrics and QOL remains unclear.
Methods: A retrospective cohort study was conducted among patients undergoing laminoplasty or laminectomy with fusion for the treatment of multilevel CSM. QOL and radiographic data were collected preoperatively and postoperatively between 2008 and 2015. The EQ-5D instrument served as a measure of overall QOL, while the PDQ measured disability and the PHQ-9 assessed mental health. Radiographic metrics included C2-C7 Cobb angle, C2-C7 sagittal vertical axis (SVA), and modified Ishihara index. Multivariable linear regression models were used to investigate the association between radiographic measurements and QOL, while controlling for the following variables: age, gender, marital status, type of surgical procedure, Body Mass Index, Charlson Comorbidity Index.
Results: 125 patients were eligible for inclusion. Following multivariable linear regression, change in radiographic measurements – preoperative to postoperative – did not correlate with change in QOL (Table 1). Similarly, change in radiographic measurements was not associated with achieving a minimum clinically important difference (MCID) in any of the QOL instruments (Table 2). When preoperative radiographic measurements were compared to change in QOL, SVA was found to be a statistically significant predictor of improvement in EQ-5D (p = 0.03; ß = 0.0004). All other preoperative radiographic measurements showed no correlation with change in QOL (Table 3).
Conclusions: Cobb angle and Ishihara index were not associated with QOL. One statistical model revealed an association between preoperative SVA and improvement in EQ-5D; however, the small ß coefficient indicates that this correlation is unlikely to be clinically significant. We therefore conclude that radiographic outcomes are a poor surrogate for QOL in patients undergoing posterior surgery for multilevel CSM.
Patient Care: The present study finds little correlation between radiographic outcomes and QOL in patients undergoing posterior surgery for multilevel CSM. Our results have the potential to influence the preoperative decision-making process by discouraging surgeons from using radiographs to predict whether a patient's QOL will improve postoperatively.
Learning Objectives: By the end of this session, participants should be able to: 1) Identify several of the radiographic and QOL metrics commonly used for outcome assessment in multilevel CSM patients; 2) Describe the correlation between radiographic outcomes and QOL in multilevel CSM patients undergoing posterior cervical surgery.