Are there distinct patterns of clinical deficits in cervical deformity? A discriminant analysis of health-related quality of life measures.

Abstract

ObjectiveWhile health-related quality of life (HRQOL) measures have been extensively quantified in cervical deformity (CD), this clinical dimension has not yet been fully integrated into understanding CD radiographic subtypes prior to surgery. The aim of this study was to identify distinct patterns of HRQOL deficits among patients with CD by focusing on clinical scores and to examine the association of these patterns with radiographic morphotypes of CD.MethodsThis was a retrospective analysis of a prospective multicenter database of patients with CD aged 18 years or older. Patient-reported outcome measures consisted of the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) scale, and Swallowing Quality of Life (SWAL-QOL) questionnaire. After performing a principal component analysis on the individual questions of the NDI, mJOA, and SWAL-QOL, 4 factors with eigenvalues > 1 were retained and included in a cluster analysis to assign patients into homogeneous groups of outcomes. Moreover, a subgroup of patients with severe deformity was described and analyzed.ResultsOverall, 134 patients (59% female, mean age ± SD 60.9 ± 10.8 years) were included in this analysis. The mean HRQOL scores were NDI, 49.1 ± 17.6; mJOA, 13.5 ± 2.7; and EQ-5D, 0.7 ± 0.1). The factor analysis involving NDI, SWAL-QOL, and mJOA revealed 4 clusters. Cluster A represented patients with a predominant sleep problem. Cluster B was patients with the lowest neck disability. Cluster C represented the most disabled patients in terms of dysphagia and neck disability. Cluster D represented patients with myelopathy. Among the 71 patients with severe deformity, the distribution of cervical morphotypes significantly differed across the 4 clusters of disability (p = 0.009). Cluster C mainly consisted of patients with cervicothoracic deformity (66.7%, p = 0.002). Cluster D had a large proportion of patients (66.7%) with focal deformity (p = 0.007). In clusters A and B, 57.9% and 46.4% of patients, respectively, presented with "flat neck" deformity (p = 0.02).ConclusionsDistinct patterns of HRQOL deficits were observed across a heterogeneous population of patients with CD, and these patterns were associated with specific radiographic morphotypes. These findings provide a framework for the next generation of CD classification, wherein HRQOL measures are combined with radiographic parameters.