A novel unembalmed human cadaveric limb model for assessing conformational changes in self-expanding nitinol stents in the popliteal artery.

OBJECTIVE: To develop an unembalmed human cadaveric lower limb model as a more realistic environment for testing self-expanding nitinol stents. We studied conformational changes and strain induced by knee flexion in nitinol stents deployed in the popliteal artery (PA). METHODS: One Lifestent® each was deployed into one limb of four cadavers (control group), while the contralateral leg received a different stent (Absolute®, Protégé Everflex®, Supera®, and Gore Viabahn®). The limbs were mounted on a quasi-static knee rig (QKR) and X-ray imaging was performed at pre-defined knee flexion angles. A least-squares solution to the equation of a circle was used to assess radius of curvature at flexion points (FP), and nominal strain was calculated for each stented artery. RESULTS: There were differences but also some similarities in conformational changes seen in the various stents. Knee flexion produced at least two FP in all stents. The mean radius of curvature decreased with increasing degrees of flexion but more so in distal (main) than proximal (accessory) FP (22 mm vs. 11 mm) in all stents. Supera® stent had the greatest relative radii of curvatures, and Absolute® stent had the highest strain value in comparison to the contralateral PA as the control group. CONCLUSION: This study describes a novel human cadaveric limb model for testing self-expanding nitinol stents implanted in the PA. Several parameters of conformational change in the stented PA such as FP formation, FP translocation and strain induced by axial compression were described. These may be useful for developing new stents for the PA location.

Outcomes of Protocol-Driven Venous Thromboembolic Chemo-Prophylaxis in Trauma Patients: A Trauma Quality Improvement Project Analysis.

INTRODUCTION: Low molecular weight heparin (LMWH) is the standard for venous thromboembolic (VTE) chemo-prophylaxis in trauma patients; however, inconsistencies in the use of LMWH exist. The objective of this study was to assess VTE outcomes in response to a chemo-prophylaxis protocol guided by patient physiology (eg, creatinine clearance) and comorbidities. METHODS: ACS TQIP Benchmark Reports at a level 1 trauma center using a patient physiology and comorbidity directed VTE chemo-prophylaxis protocol were analyzed for Spring 2019 to Fall 2021. Patient demographics, VTE rates and pharmacologic VTE prophylaxis type were collected for "All Patients" and "Elderly" (TQIP: age ≥ 55 years) cohorts. RESULTS: Data was analyzed for 1919183 "All Hospitals" (AH) and 5843 patients single institution (SI) using the physiologic and comorbidity guided VTE chemo-prophylaxis protocol. Elderly subgroup had 701965 (AH) and 2939 (SI) patients. Use of non-LMWH chemo-prophylaxis was significantly higher at SI: All patients = 62.6% SI vs 22.1% (P < .01); Elderly = 68.8% SI vs 28.1% AH (P < .01). VTE, DVT, and PE rates for All Patients and Elderly subgroup were significantly reduced at SI, except Elderly PE which was statistically equivalent. CONCLUSIONS: Protocol-driven VTE chemo-prophylaxis was associated with significantly lower LMWH use accompanied by significant reductions in All VTE, DVT, PE, and Elderly VTE and DVT with no difference in Elderly PE rates. These results may imply that adherence to a physiologic and comorbidity directed chemo-prophylaxis protocol, rather than LMWH, reduces VTE events in trauma patients. Further investigation to elucidate best practice is warranted.

Thoracoscopic-assisted rib plating (TARP): initial single-center case series, including TARP in the super elderly, technical lessons learned, and proposed expanded indications.

Objectives: The application of surgical stabilization of rib fractures (SSRF) remains inconsistent due to evolving indications and perceived associated morbidity. By implementing thoracoscopic-assisted rib plating (TARP), a minimally invasive SSRF approach, we expanded our SSRF application to patients who otherwise might not be offered fixation. This report presents our initial experience, including fixation in super elderly (aged ≥85 years), and technical lessons learned. Methods: This was a retrospective cohort study at a level 1 trauma center of admitted patients who underwent TARP between August 2019 and October 2020. Patient demographics, injury characteristics, surgical indications and outcomes are represented as mean±SD, median or percentage. Results: A total of 2134 patients with rib fractures were admitted. In this group, 39 SSRF procedures were performed, of which 54% (n=21) were TARP. Average age was 68.5±16 years. Patients had a median of 5 fractured ribs, with an average of 1 rib that was bicortically displaced, and 19% presented with 'clicking' on inspiration. Patient outcomes were a mean hospital length of stay (LOS) of 11±3.7 days, mean postoperative LOS of 8 days, and mean intensive care unit LOS of 6.6±2.9 days. Five patients were ≥85 years old with a mean age of 90.8±4.7 years. They presented with an average of 4 rib fractures, of which an average of 2.4 ribs were plated. The procedure was well tolerated in this age group with a hospital LOS of 9.4±2 days, and all five patients were discharged to a rehab facility with no in-hospital mortalities. Conclusion: Our experience incorporating TARP at our institution demonstrated feasibility of the technique and application across a broad range of patients. This approach and its application warrants further evaluation and potentially expands the application of SSRF..