RESUMEN
Animal studies are essential to biomedical research and the cornerstone is a reproducible animal model. While there are many reports on rodent peripheral nerve injury models, a large animal model is essential to confirm the effects of nerve regeneration over the longer distances of regeneration required in humans. Swine have long been used as a large animal model for other surgical and biomedical studies. This paper represents a novel neurovascular injury model in the Sus scrofa domesticus swine (American Yorkshire pig). This paper will describe our experience and recommendations with pre-operative, operative and post-operative protocols and our refinements to produce an effective model.
Asunto(s)
Arteria Femoral , Sus scrofa , Animales , Modelos Animales de Enfermedad , Arteria Femoral/cirugía , Isquemia , Regeneración Nerviosa , Nervio Ciático , PorcinosRESUMEN
INTRODUCTION: Despite greater than 60,000 nonfatal firearm injuries per year in the United States, retained shrapnel is a relatively rare cause of systemic lead toxicity with less than 100 cases reported in the medical literature since 1867. While intra-articular retained shrapnel as a cause of lead toxicity is well-described, extra-articular fragments are less well known to cause symptomatic disease. CASE REPORT: A 31-year-old man initially presented with abdominal pain, constipation, jaundice, and elevated liver transaminases approximately 3 weeks after suffering a left lower extremity injury during athletic activity. The patient was found to have steatohepatitis after extensive inpatient and outpatient gastroenterological workup to include upper and lower endoscopy, liver ultrasound, and biopsy of the liver to confirm the diagnosis. Imaging was incidentally notable for retained gunshot in the left flank and large shell fragment containing seroma in the left thigh. The patient was initially discharged with improved pain, but later presented to a primary care clinic with weight loss and continued pain. This was followed by a subsequent progression to diffuse weakness, ultimately resulting in an inability to ambulate. The patient was readmitted to a tertiary care medical center, 3 months after the initial presentation. Physical exam was then notable for 70-lb weight loss from initial admission and diffuse peripheral weakness with global muscle atrophy. Following a broad differential workup, he was found to have a blood lead level of 129 µg/dL, and hemoglobin of 7.7 g/dL with basophilic stippling on peripheral smear. The patient was transferred to the intensive care unit for chelation therapy with dimercaprol and calcium ethylenediaminetetraacetic acid. Lead levels initially decreased, but rose when patient was transitioned to oral therapy with succimer. Surgery was consulted for removal of multiple retained fragments, which were analyzed by the Joint Pathology Center and found to contain lead. The patient's motor function gradually improved on oral chelation and he was discharged to a subacute rehabilitation facility. CONCLUSION: This complex case describes a rare cause for a relatively common clinical presentation, jaundice and hepatitis, and reinforces the importance of longitudinal follow up and reassessment of a patient with an unknown illness and worsening clinical condition. Diagnosis of systemic lead toxicity is challenging because of its protean clinical manifestations, and relative rarity with the advent of strict environmental lead controls and decrease in lead-based paint and industrial products. Furthermore, extra-articular lead remains a rare cause of systemic toxicity, and the surgical standard of care has been to not remove these fragments in gunshot victims. This case adds to a small amount of evidence that lead screening may be of value in selected patients with extra-articular retained shrapnel, especially those with seroma and osteophyte formation in the wound.