Effects of Motion-Sparing Versus Nonmotion-Sparing Cervical Spine Surgery on Total Shoulder Arthroplasty.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: This study investigates the impact of cervical spine procedures on postoperative outcomes of TSA, considering the growing evidence of interconnected cervical and shoulder pathologies. SUMMARY OF BACKGROUND DATA: The increasing prevalence of both total shoulder arthroplasty (TSA) and cervical spine surgeries indicates a possible overlap in patient populations and related pathologies. METHODS: We analyzed the TriNetX database records from 86 health care organizations, spanning January 1, 2012, to March 12, 2024, for patients who had undergone either motion-sparing cervical procedures or cervical fusion before TSA using CPT and ICD-10 codes for cohort identification. Patients were then categorized according to their cervical procedure; 1:1 propensity score matching was performed to adjust for variables including age, race, sex, diabetes, heart failure, chronic kidney disease, liver disease, and chronic obstructive pulmonary disease. The study assessed 90-day medical complications and 2-year mechanical outcomes, comparing categorical variables using the χ2 exact test with univariate regressions. Patient outcomes, odds ratios, 95% CIs, and P-values were reported. RESULTS: The study examined 4509 patients, with 2702 receiving motion-sparing procedures and 1807 undergoing cervical fusion before TSA. After propensity matching to adjust for demographic and comorbidity differences, the 90-day outcomes showed a significantly higher infection rate in the motion-sparing group compared with the fusion group [2.0% vs. 1.1%; OR: 1.806, CI (1.026, 3.179), P=0.038]. No significant differences were observed in other short-term outcomes or in 2-year mechanical complications such as periprosthetic dislocation, joint infection, aseptic loosening, or revision surgeries, all showing comparable rates. CONCLUSION: These findings suggest that although infection rates may differ depending on the type of cervical surgery performed, these surgeries do not impact the long-term mechanical outcomes of TSA. Consequently, the type of cervical surgery should not influence the assessment of a patient's suitability for TSA.