Dhodapkar, Meera M.

Background. Negative pressure wound therapy promotes wound healing through fluid removal, edema reduction, and mechanical contraction. A novel thermoplastic elastomer (TPE) dressing has been developed to improve exudate evacuation and reduce tissue ingrowth, but its effect on wound contraction compared with reticulated open cell foam (ROCF) remains unclear. Objective. To compare the degree of wound contraction with the TPE dressing, ROCF, or no filler at different wound depths and negative pressure settings in a porcine explant model. Materials and Methods. The effect of the materials or lack thereof on wound contraction was investigated at 2 wound depths (shallow, deep) and 3 negative pressure settings (−50 mm Hg, −80 mm Hg, and −125 mm Hg). Wound width was measured at 3 standardized locations before and during therapy. Univariable and multivariable linear regression analyses were performed to identify factors associated with contraction. Results. A total of 810 measurements were obtained. Both the TPE dressing and ROCF demonstrated statistically significantly greater contraction than no filler. In deep wounds, greater contraction was noted with the TPE dressing compared with ROCF. Higher negative pressure and increased wound depth were independently associated with greater contraction. Absolute differences in contraction between dressings were small (<3 mm across all conditions). Conclusion. The TPE dressing provides equivalent or greater wound contraction compared with ROCF, particularly in deep wounds, without impairing macrodeformation. Given the small magnitude of differences, the clinical relevance of this finding likely depends on additional factors, which should be evaluated in future in vivo studies.

ABSTRACT Negative pressure wound therapy relies on suction, commonly set to −125 mmHg, to evacuate wound fluid, but dysvascular and pressure injuries often respond unpredictably. Newton's third law indicates that negative pressure applies an equal and opposite contact pressure on the wound surface, and this study quantified this contact pressure across dressing types, wound configurations and suction levels. Using a porcine explant model, central and peripheral contact pressure measurements were obtained beneath black reticulated open cell foam, white foam and a novel thermoplastic elastomer dressing across plexiglass, intact skin, shallow and deep wounds under −50, −75 and −125 mmHg. Contact pressure increased proportionally with negative pressure, and multivariable modelling demonstrated that dressing type, wound type and suction level significantly influenced pressure, with negative pressure explaining most of the variance (0.77 and 0.68). Thermoplastic elastomer at −50 mmHg in deep wounds produced the lowest contact pressure, whereas black reticulated open cell foam and white foam at −125 mmHg generated elevated contact pressures of approximately +125 to +195 mmHg. These findings show that black reticulated open cell foam at conventional −125 mmHg can create hypoperfusion conditions, whereas thermoplastic elastomer consistently produces the lowest pressures and may enhance perfusion at lower suction levels, offering a physiologic explanation for improved clinical outcomes in dysvascular and pressure injuries treated with reduced negative pressure.

BACKGROUND Septic facet cysts are a rare phenomenon reported in the literature among immunocompromised hosts and may require operative intervention for appropriate source and symptomatic control. OBSERVATIONS A 70-year-old male with a past medical history of immunoglobulin A lambda smoldering myeloma degenerative lumbar disease who presented with low back and radicular lower extremity pain was found to have a left L4–5 septic facet cyst with extension to the epidural space. Intraoperative cultures were positive for Nocardia species. Staging workup revealed progression to high-risk-profile multiple myeloma. LESSONS Patients with septic facet cysts may require operative intervention for appropriate source control. Nocardia spine infections and septic facet cysts are rare and require investigation of preexisting risk factors and any potential underlying immunocompromise. https://thejns.org/doi/10.3171/CASE25220

OBJECTIVES: To compare whether femoral version more closely mirrors the contralateral femur or a population norm estimate of 15 degrees of anteversion. METHODS: Design: Radiologic observational study. Setting: Level I Trauma Center. Patient Selection Criteria: Patients with no history of anatomy-altering femoral injury who underwent bilateral lower extremity computed tomography scans. Outcome Measures and Comparisons: Computed tomographies were analyzed to measure femoral version on each side. The asymmetry in femoral version between left and right in each patient (interfemoral rotational variance [IRV]) was recorded. The difference of each femur's version from a proposed population mean of 15 degrees of anteversion was also recorded. RESULTS: A total of 219 patients with a mean femoral version of 14.9 degrees ± 10.5 degrees of anteversion were included. Mean IRV was 5.3 degrees, compared with 8.2 degrees of mean variation from the population norm of 15 degrees of anteversion (P < 0.001). Five percent of patients had IRV >15 degrees compared with 15% that had femoral rotation >15 degrees from the population mean of 15 degrees (P < 0.001). CONCLUSIONS: In the setting of a comminuted diaphyseal femur fracture, knowledge of the appropriate target for restoration of rotational alignment is critical. This radiologic cohort study found that on average, femoral version more closely mirrors an individual patient's contralateral femur as opposed to a population norm of 15 degrees of anteversion.