Association between subaxial paraspinal muscle parameters and cervical vertebral bone quality in preoperative patients.

Objective: Evidence that individuals with osteoporosis have an increased susceptibility to and frequency of sarcopenia has led to the creation of the term "osteosarcopenia." Given the limitations of dual-energy X-ray absorptiometry in spine bone mineral density assessment, novel techniques such as MRI-based vertebral bone quality (VBQ) are increasingly being utilized to quantify site-specific bone quality in the spine. The relationship between cervical paraspinal muscle morphology and cervical bone quality has not been investigated. This study aimed to explore the relationship between cervical VBQ scores and paraspinal muscles parameters.

Methods: Patients with preoperative cervical MRI who underwent anterior cervical discectomy and fusion between 2015 and 2018 were reviewed. Muscles from C3 to C7 were categorized into 4 functional groups: sternocleidomastoid, anterior, posteromedial, and posterolateral groups. For all groups, the cross-sectional area (CSA), functional CSA (fCSA), and percent fat infiltration (FI) were measured. VBQ scores of the cervical vertebral bodies were performed using prior established methodologies. Multivariable linear regression analyses adjusted for age, sex, and body mass index were performed. The Benjamini-Hochberg procedure was applied to adjust p values.

Results: A total of 75 patients (median age 55.4 years; 26 females) were included. A greater VBQ score indicates high fat content of the bone and was significantly associated with the presence of osteopenia/osteoporosis, meaning that high VBQ scores indicate lower bone quality and low VBQ scores indicate better bone quality. After adjustment for age, sex, and body mass index and adjustment of the p values with the Benjamini-Hochberg procedure, regression analysis revealed significant negative associations between fCSA of the anterior muscle group and VBQ scores and a significant positive association between FI of the anterior muscle group with VBQ scores from C2 to T1.

Conclusions: This study presents novel insights into the relationship between cervical vertebral bone mineral quality and paraspinal muscle parameters, particularly at the C3 level, which showed the highest number of significant associations. The findings suggest that measurements of paraspinal muscles at C3 could serve as a proxy for assessing bone quality across the subaxial cervical spine, offering a new perspective in preoperative evaluations for cervical spine surgery. This study is the first to report significant associations between VBQ and paraspinal muscle parameters throughout the subaxial cervical spine.