Photochemical sealing of a nerve wrap over the repair site isolates and optimizes the regenerating nerve microenvironment. To facilitate clinical adoption of the technology, we investigated photosealed autologous tissue in a rodent sciatic nerve transection and repair model. Rats underwent transection of the sciatic nerve with repair performed in three groups: standard microsurgical neurorrhaphy (SN) and photochemical sealing with a crosslinked human amnion (xHAM) or autologous vein. Functional recovery was assessed at four-week intervals using footprint analysis. Gastrocnemius muscle mass preservation, histology, and nerve histomorphometry were evaluated at 120 days. Nerves treated with a PTB-sealed autologous vein improved functional recovery at 120 days although the comparison between groups was not significantly different (SN: −58.4 +/− 10.9; XHAM: −57.9 +/− 8.7; Vein: −52.4 +/− 17.1). Good muscle mass preservation was observed in all groups, with no statistical differences between groups (SN: 69 +/− 7%; XHAM: 70 +/− 7%; Vein: 70 +/− 7%). Histomorphometry showed good axonal regeneration in all repair techniques. These results demonstrate that peripheral nerve repair using photosealed autologous veins produced regeneration at least equivalent to current gold-standard microsurgery. The use of autologous veins removes costs and foreign body concerns and would be readily available during surgery. This study illustrates a new repair method that could restore normal endoneurial homeostasis with minimal trauma following severe nerve injury.

Peripheral nerve injuries affect 13–23 per 100,000 people annually in the U.S. and often result in motor and sensory deficits. Microsurgical suture repair (SR) is the standard treatment but is technically challenging and associated with complications. Photochemical tissue bonding (PTB), which uses light and a photoactivated dye to bond collagenous tissues, offers a promising alternative. We compared PTB with commercially available collagen membranes for SR and PTB using cryopreserved human amnion (HAM) in a rat sciatic nerve transection model. In total, 75 Lewis rats underwent nerve repair with one of five methods: SR, PTB-HAM, PTB with commercial collagenous membranes (human amnion monolayer (AML), human amnion–chorion–amnion trilayer (ATL), or swine intestinal submucosa (SIS)). Functional recovery was assessed with walking tracks and the Static Sciatic Index (SSI) at days 30, 60, 90, and 120; histological evaluations at days 30 and 120 examined inflammation, axon density, and fascicle structure. No significant differences in SSI scores were found between groups, though PTB-AML and PTB-SIS improved over time. Histology showed inflammation at day 30 that decreased by day 120. Histomorphometry revealed similar axon regeneration across groups. These results suggest that PTB with commercial membranes is a viable alternative to SR.

Background: Acute compartment syndrome (ACS) is a time-sensitive diagnosis, with mortality rates as high as 15%. Diagnosis relies on clinical evaluation and intracompartmental pressure (ICP) measurements, which are only 68% accurate. Microdialysis has been shown to be reliable in detecting flap ischemia before clinically evident. Therefore, we hypothesized that intramuscular (IM) microdialysis could detect early ACS with high diagnostic test accuracy (DTA). Given IM perforators supply overlying skin, we further hypothesized that subcutaneous (SC) biomarkers closely correlate with IM metabolic changes and can detect ACS in a swine model. Methods: Eleven Yorkshire swine (male, ~50 kg) were used to model tourniquet-induced ACS in the bilateral anterior hind limbs (n=22). ACS was induced for 6 hours. Microdialysis probes were placed in both IM and SC tissue compartments to collect interstitial fluid for analysis of glucose, pH, and lactate. Tissue oxygenation (SrO ₂ ) and hindlimb temperature were also monitored. Maximal diagnostic test accuracy and correlation coefficients were calculated for these metrics. Results: ICP increased immediately after tourniquet inflation [preinflation: 15.6±4.7 mm Hg vs. postinflation: 53.0±38.2 mm Hg ( P =0.0012)]. IM glucose decreased significantly at hour 2, while SC glucose decreased significantly at hour 3. SC glucose below 6.6 mg/dL had a DTA of 75%. Both IM and SC pH decreased significantly at hour 2. SC pH below 7.17 had a DTA of 78%. IM and SC lactate increased over the course of the experiment, but these changes were not statistically significant. SC lactate above 3.85 mg/dL had a DTA of 70%. SrO ₂ decreased significantly immediately after tourniquet inflation (DTA 100% below 58.5%), and hindlimb temperature decreased significantly within 30 minutes (DTA 99.6% below 27.8 °C). SC and IM glucose had the closest correlation ( R ² =0.931), followed by pH ( R ² =0.911), while lactate showed a less reliable correlation ( R ² =0.667). Conclusions: In a porcine model of ACS, SC biomarkers closely correlate with IM biomarkers and exhibit a high DTA with pH, having the highest accuracy. SrO ₂ , and surface temperature also decreased rapidly and significantly. Future research should investigate these modalities in pilot clinical trials.