Outcomes and Complications of Halo Vest Immobilization in Adults with Cervical Spine Injuries: A 10-Year Retrospective Cohort Study In a Tertiary UK Centre

Background Halo vest immobilization remains a widely utilized non-surgical treatment for cervical spine fractures. However, comprehensive data on complication rates, fusion outcomes, and factors influencing treatment success are limited, particularly regarding clinical decision-making when radiologic fusion is incomplete. Objective To evaluate complication rates, fusion outcomes, predictive factors for treatment success, and clinical decision-making patterns in adult patients undergoing halo vest immobilization for cervical spine injuries. Methods This retrospective cohort study analysed 205 adult patients (mean age 56.6 ± 16.6 years; 62.4% male) treated with halo vest immobilization for cervical spine injuries at a tertiary spine centre from 2012–2022. Patient demographics, fracture characteristics, comorbidities, smoking status, complications, and fusion outcomes were recorded. Statistical analysis included chi-square tests, Mann-Whitney U tests, and multivariable logistic regression to identify predictors of complications, fusion success, and surgical intervention. Kaplan-Meier survival analysis assessed time to fusion. Results Fracture distribution included C2 (36%), subaxial cervical spine (42%), C1/C2 combined (12%), and C1 alone (7%). Mean duration of halo immobilization was 169.9 ± 92.3 days. Complications occurred in 37.6% of patients, with pin-site infection being most common (minor: 16.1%, severe: 6.3%). Complete or partial fusion was achieved in 57.6% of patients (95% CI: 50.6–64.3%), while 26.8% showed no radiologic fusion but were deemed clinically stable for halo removal based on dynamic imaging and absence of neck pain. Younger age (41–65 years) was associated with longer immobilization duration (206 days vs. 114 days in patients > 65, p < 0.001). Smoking status showed no significant association with fusion rates (p = 0.42) but was associated with increased movement on dynamic imaging (12.3% vs. 5.7% in non-smokers, p = 0.03). The surgical conversion rate was 22.0%, with non-union (24.4% of surgical cases), progression of instability (24.4%), and infection requiring operative management (22.2%) being the primary indications. Overall mortality was 0.5% (n = 1). Conclusion Halo vest immobilization remains an effective treatment modality for cervical spine injuries in adults with acceptable complication rates and low mortality. Clinical stability assessed through dynamic flexion-extension imaging provides a safe criterion for discontinuing halo immobilization in approximately one-quarter of patients despite incomplete radiologic fusion. This finding supports a paradigm shift toward functional outcome assessment rather than strict reliance on static radiologic fusion criteria. Younger patients and those with complex fracture patterns require longer immobilization periods.