Radiographic, Pulmonary, and Clinical Outcomes With Halo Gravity Traction

Study design: Single-center retrospective chart review.

Objectives and summary: Halo gravity traction (HGT) is a safe and effective intervention to improve spinal deformity prior to corrective instrumentation. Our study aimed to report on a large series of patients undergoing HGT, demonstrate the correlation between thoracic height achieved and pulmonary function, and evaluate the efficacy of nutritional assessment and intervention while in HGT for these often malnourished or nutritionally compromised patients.

Methods: 107 patients underwent HGT for severe spinal deformity. Major coronal and sagittal Cobb angles, T1-T12 ht, and T1-S1 ht were collected pre-HGT, during HGT, postoperation, and 2 years postoperation. Pulmonary function tests (PFTs) recorded forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). Nutritional interventions such as formal nutrition consult, resulting nutritional supplementation, or interventions were recorded.

Results: Patients were in HGT for mean of 82.1 days and mean maximum percentage body weight in traction was 49.5%. Mean major coronal Cobb angle prior to HGT was 92.6°, improving to 65.8° in maximal traction and to 47° after surgical intervention. Traction accounted for 78% of T1-T12 height and 79% of T1-S1 length gains from pre- to postoperation. We showed a positive correlation between gain in T1-T12 height and percentage predicted changes in FVC and FEV1. Weight Z score for the entire cohort of patients improved from -2.8 pretraction to -2.4 in traction and then to -2.3 postoperative.

Conclusions: Our study again demonstrated that HGT achieves radiographic improvement safely and effectively in severe spinal deformity. We demonstrated a positive correlation between improvement in PFTs and increase in thoracic height seen with HGT. Additionally, improvement in weight Z score was seen in the entire population and the most at risk patients for malnutrition, results that have not been shown before.

Level of evidence: Level IV.