Sternal Closure Techniques in High-BMI Patients Undergoing Open-Heart Surgery: A Retrospective Observational Comparison of Cable and Wire Systems

Elevated body-mass index (BMI ≥ 30 kg/m²) is an established risk factor for sternal wound complications after median sternotomy, yet consensus is lacking on the optimal closure technique in this high-risk subgroup. Conventional monofilament stainless-steel wiring remains the worldwide standard because it is inexpensive and familiar, but multifilament cable systems provide greater fatigue strength and more uniform load distribution in bench testing and early clinical reports. Previous meta-analyses report conflicting results-some indicating fewer sternal complications with rigid fixation, others showing no clear benefit-largely because they pool heterogeneous populations in which obesity is often only one of many overlapping risk factors. The present study isolates the effect of BMI by retrospectively analysing all adult patients (≥18 years) with BMI ≥ 30 kg/m² who underwent primary open-heart surgery at a single tertiary centre from 1 January 2020 through 31 December 2024. Patients are stratified by the sternal closure method actually used-standard simple/figure-of-eight wires versus a commercially available rigid cable system (RTI Surgical Sternal Cable). By excluding other indications for rigid fixation (eg, age ≥ 80, dialysis, osteoporosis, COPD, bilateral internal mammary harvest, mediastinitis, early re-exploration, re-do sternotomy), the analysis aims to discern whether obesity alone modifies the relative performance of the two techniques. De-identified peri-operative data are extracted from electronic records under institutional ethics approval, and pre-specified statistical comparisons will quantify associations between closure method and postoperative sternal instability, surgical site infection, need for reoperation, and resource utilisation (ICU and total hospital length of stay). Findings are expected to refine evidence-based recommendations for sternal closure in high-BMI cardiac-surgery patients.