Porcine Model of Acute Compartment Syndrome.

OBJECTIVES: Acute compartment syndrome is a devastating condition associated with lasting consequences or even death if not treated in a timely fashion. Current preclinical modeling is inadequate. Ideally a model should mimic human disease. There should be a trauma-induced reperfusion or direct muscle event that causes gradual increased pressure and is amenable to release with fasciotomy. We have attempted to reproduce this mechanism and outcome in a porcine model. METHODS: Anterior tibial musculature was injured with vascular occlusion plus exterior tourniquet crush or direct intracompartmental crush through balloon inflation. The injury was maintained for over 5 hours. At that time, the tourniquet or balloon was removed. The injuries were continuously monitored with an intramuscular continuous pressure sensor. Pressure changes were recorded and after 2 hours of postinjury observation, a fasciotomy was performed for the muscle compartment. RESULTS: Pressures were brought to 100 mm Hg during the injury phase. During the two-hour observation period, the balloon catheter technique achieved an average pressure of 25.1 ± SD 8.8 mm Hg with a maximum reading of 38.2 mm Hg and minimum reading of 14.1 mm Hg. During this same period, the ischemia-reperfusion + direct crush technique achieved an average pressure of 33.7 ± SD 7.3 mm Hg, with a maximum reading of 43.5 mm Hg and minimum reading of 23.5 mm Hg. Average pressure postfasciotomy for the balloon catheter technique was 2.4 ± SD 2.5 mm Hg; and for the crush technique, average value postfasciotomy was 4.9 ± SD 3.7 mm Hg-both representing a return to physiologic levels. CONCLUSION: This is the first preclinical model that shows the same response to injury and treatment as is observed in human physiology. Surgical and nonsurgical therapies for compartment syndrome can now be tested reliably.

Acute Compartment Syndrome Modeling with Sequential Infusion Shows the Deep Posterior Compartment Is Not Functionally Discrete.

BACKGROUND: Clinical case series have indicated that 1 or 2-compartment decompression of the anterior or lateral leg may be sufficient for release, but, currently, no cadaveric model has verified that approach. The objective of this study was to investigate the functional relationship between compartments by alternating sequences of infusion and fasciotomy release. METHODS: This study utilized multicompartment sequential pressurization with simultaneous monitoring by continuous pressure sensors to model compartment syndrome in a human cadaver leg. Subsequent sequential release of compartments and continuous streaming of pressure readings permitted unique insights. RESULTS: A leg model allowed the examination of pressure changes in all 4 compartments as treated with sequential fasciotomies. The successful modeling of lower-leg pressures consistent with compartment syndrome showed that discrepancies relative to accepted concepts were seen when the deep posterior compartment was pressurized in isolation. Also, release of 1 of the 2 of either the anterior or lateral compartments seems to be sufficient for decompression to acceptable pressure levels. CONCLUSIONS: The deep posterior compartment does not appear to be completely discrete and instead follows the pressurization curve of the posterior muscle group. This indicates that release of the deep posterior compartment may not be needed in all acute compartment syndrome scenarios. CLINICAL RELEVANCE: Surgical techniques can be modified for treatment of acute compartment syndrome to avoid large scar lengths, deep dissection, and multiple exposures that could improve patient outcomes.

Engineering surgical stitches to prevent bacterial infection.

Surgical site infections (SSIs) account for a massive economic, physiological, and psychological burden on patients and health care providers. Sutures provide a surface to which bacteria can adhere, proliferate, and promote SSIs. Current methods for fighting SSIs involve the use of sutures coated with common antibiotics (triclosan). Unfortunately, these antibiotics have been rendered ineffective due to the increasing rate of antibiotic resistance. A promising new avenue involves the use of metallic nanoparticles (MNPs). MNPs exhibit low cytotoxicity and a strong propensity for killing bacteria while evading the typical antibiotic resistance mechanisms. In this work, we developed a novel MNPs dip-coating method for PDS-II sutures and explored the capabilities of a variety of MNPs in killing bacteria while retaining the cytocompatibility. Our findings indicated that our technique provided a homogeneous coating for PDS-II sutures, maintaining the strength, structural integrity, and degradability. The MNP coatings possess strong in vitro antibacterial properties against P aeruginosa and S. aureus-varying the %of dead bacteria from ~ 40% (for MgO NPs) to ~ 90% (for Fe2O3) compared to ~ 15% for uncoated PDS-II suture, after 7 days. All sutures demonstrated minimal cytotoxicity (cell viability > 70%) reinforcing the movement towards the use MNPs as a viable antibacterial technology.

Minimal Percutaneous Release for Acute Compartment Syndrome of the Foot: A Case Report.

CASE: A 34-year-old man had an injury which resulted in pilon fracture and acute compartment syndrome of his forefoot. The case report describes the use of a novel minimally invasive dorsal approach for decompression of the lateral, central, medial, and interosseous compartments. The release was performed through multiple small incisions on the dorsal foot. The patient had complete relief with normal function of all muscle groups at 6 weeks and is now 18 months after surgery. He has returned to full activity. CONCLUSION: The successful decompression of the forefoot compartments through a percutaneous approach avoided known complications of muscle death, toe clawing, and secondary surgeries.

Percutaneous Forefoot Decompression in a Foot Compartment Syndrome Model.

BACKGROUND: Acute compartment syndrome of the foot is a controversial topic. Release of the foot has been seen as complicated because of large incisions and postoperative morbidity, and there has been debate over whether this procedure is actually effective for releasing all areas of increased pressure. New sensor technology affords the opportunity to advance our understanding of acute compartment syndrome of the foot and its treatment. The purpose of the present study was to determine whether percutaneous decompression could be performed for the treatment of compartment syndrome in a forefoot model. METHODS: The present study utilized a validated continuous pressure sensor to model compartment syndrome in human cadaveric feet. We utilized a pressure-controlled saline solution infusion system to induce increased pressure. A novel percutaneous release of the forefoot was investigated to assess its efficacy in achieving decompression. RESULTS: For all cadaveric specimens, continuous pressure monitoring was accomplished with use of a continuous pressure sensor. There were 4 discrete compartment areas that could be reliably pressurized in all feet. The average baseline, pressurized, and post-release pressures (and standard deviations) were 4.5 ± 2.9, 43.8 ± 7.7, and 9.5 ± 3.6 mm Hg, respectively. Percutaneous decompression produced a significant decrease in pressure in all 4 compartments (p < 0.05). CONCLUSIONS: With use of continuous compartment pressure monitoring, 4 consistent areas were established as discrete compartments in the foot. All 4 compartments were pressurized with a standard pump system. With use of 2 small dorsal incisions, all 4 compartments were successfully released, with no injuries identified in the cutaneous nerve branches, extensor tendons, or arteries. These results have strong implications for the future of modeling compartment syndrome as well as for guiding clinical studies. CLINICAL RELEVANCE: A reproducible and accurate method of continuous pressure monitoring of foot compartments after trauma is needed (1) to reliably identify patients who are likely to benefit from compartment release and (2) to help avoid missed or evolving cases of acute compartment syndrome. In addition, a reproducible method for percutaneous compartment release that minimizes collateral structural damage and the need for secondary surgical procedures is needed.

Electroceutical Silk-Silver Gel to Eradicate Bacterial Infection.

With more than 50% of bacteria resistant to standard antibiotics, new strategies to treat bacterial infection and colonization are needed. Based on the concept of targeting the bacteria synergistically on various fronts, it is hypothesized that an electrical insult associated with antibacterial materials may be a highly effective means of killing bacteria. In this work, an injectable conductive gel based on silk fibroin (SF) and silver nanoparticles (Ag-NPs) is synthesized, capable of coating a zone of injury, allowing the application of a low electrical current to decrease bacterial contamination. With a high conductivity of 1.5 S cm-1 , SF/Ag-NPs gels killed 80% of Escherichia coli in 1 min, no toxicity toward Chinese hamster ovary cells is observed. The mechanism of an electrical composite gel combined with electrical wound therapy is associated with silver ion (Ag+ ) release, and reactive oxygen species (ROS) production. The findings in the present study show a similar Ag+ release for treatment with gels and the combined effect, whereas ROS generation is 50% higher when a small electrical current is applied leading to a broad bactericidal effect.

Elizabethkingia Meningoseptica in a Case of Biliary Tract Infection Following Liver Transplantation.

BACKGROUND Elizabethkingia meningoseptica (E. meningoseptica) is an aerobic Gram-negative bacillus known to thrive in moist environments, and is now recognized as a hospital-acquired infection, being found to contaminate hospital equipment, respiratory apparatus, hospital solutions, water, and drainage systems. Nosocomial infection with E. meningoseptica occurs in immunocompromised patients, requires specialized identification methods, and is resistant to conventional antibiotics. We report a case of E. meningoseptica infection arising from a percutaneous transhepatic biliary drainage (PTBD) tube. CASE REPORT A 55-year-old Saudi woman underwent liver transplantation. The post-operative period immediately following transplantation was complicated by anastomotic biliary stricture and bile leak, which was managed with percutaneous transhepatic cholangiography (PTC) with PTBD. She developed right upper quadrant abdominal pain, and her ultrasound (US) showed a subdiaphragmatic collection. Microbial culture from the PTBD tube was positive for E. meningoseptica, which was treated with intravenous ciprofloxacin and metronidazole. This case is the second identified infection with E. meningoseptica at our specialist center, fifteen years after isolating the first case in a hemodialysis patient. We believe that this is the first case of E. meningoseptica infection to be reported in a liver transplant patient. CONCLUSIONS The emerging nosocomial infectious organism, E. meningoseptica is being seen more often on hospital equipment and medical devices and in water. This case report highlights the need for awareness of this infection in hospitalized immunocompromised patients and the appropriate identification and management of infection with E. meningoseptica.