A Yorkshire swine (Sus scrofa domesticus) model for nerve regeneration and ischemia based on the sciatic nerve and femoral artery.

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.

Pathogenic and rare deleterious variants in multiple genes suggest oligogenic inheritance in recurrent exertional rhabdomyolysis.

Exertional rhabdomyolysis is a metabolic event characterized by the release of muscle content into the circulation due to exercise-driven breakdown of skeletal muscle. Recurrent exertional rhabdomyolysis has been associated with metabolic myopathies and mitochondrial disorders, a clinically and genetically heterogeneous group of predominantly autosomal recessive, monogenic conditions. Although genetics factors are well recognized in recurrent rhabdomyolysis, the underlying causes and mechanisms of exercise-driven muscle breakdown remain unknown in a substantial number of cases. We present clinical and genetic study results from seven adult male subjects with recurrent exertional rhabdomyolysis. In all subject, whole exome sequencing identified multiple heterozygous variants in genes associated with monogenic metabolic and/or mitochondrial disorders. These variants consisted of known pathogenic and/or new likely pathogenic variants in combination with other rare deleterious alleles. The presence of heterozygous pathogenic and rare deleterious variants in multiple genes suggests an oligogenic inheritance for exertional rhabdomyolysis etiology. Our data imply that exertional rhabdomyolysis can reflect cumulative effects or synergistic interactions of deleterious variants in multiple genes that are likely to compromise muscle metabolism under the stress of exercise.

Combat Injury of the Sciatic Nerve - An Institutional Experience.

INTRODUCTION: Combat injury of the sciatic nerve tends to be severe with variable but often profound consequences, is often associated with widespread soft tissue and bone injuries, significant neurologic impairment, severe neuropathic pain, and a prolonged recovery time. There is little contemporary data that describes the treatment and outcome of this significant military acquired peripheral nerve injury. We describe our institution's experience treating patients with combat-acquired sciatic nerve injury in the recent Iraq and Afghanistan wars. MATERIALS AND METHODS: IRB approval was obtained, and a retrospective review was performed of the records of 5,137 combat-related extremity injuries between June 2007 and June 2015 to identify patients with combat-acquired sciatic nerve injury without traumatic amputation of the injured leg. The most common mechanisms of injury were gunshot wound to the upper thigh or pelvis, followed by blast injury. Thirteen patients were identified that underwent sciatic nerve exploration and repair. Nine patients had nerve repair using long-length acellular cadaveric allografts. Five patients underwent nerve surgery within 30 d of injury and eight had surgery on a delayed basis. The postoperative follow-up period was at least 2 yr. RESULTS: Reduction of neuropathic pain was significant, 7/10 points on the 11-point pain intensity numerical rating scale. Eight patients displayed electrodiagnostic evidence of reinnervation distal to the injury zone; however, functional recovery was poor, as only 3 of 10 patients had detectable motor units distal to the knee, and recovery was only in tibial nerve innervated muscles. There were no serious surgical complications, in particular, wound infection or graft rejection associated with long-length cadaver allograft placement. CONCLUSION: Early surgery to repair sciatic nerve injury possibly promotes significant pain reduction, reduces narcotic usage and facilitates a long rehabilitation process. Allograft nerve placement is not associated with serious complications. A follow-up period longer than 3 yr would be required and is ongoing to assess the efficacy of our treatment of patients with combat-acquired sciatic nerve injury.

High-resolution ultrasound in combat-related peripheral nerve injuries.

INTRODUCTION: Peripheral nerve injuries (PNI) sustained in combat are typically severe and are frequently associated with marked soft tissue damage, anatomic distortion, and retained metallic fragments. These features complicate clinical and electrodiagnostic assessment and may preclude MRI. METHODS: We describe 4 cases of military personnel who sustained high-velocity gunshot wounds or blasts with metal fragment injuries in which high resolution peripheral nerve ultrasound (US) proved beneficial. RESULTS: In these cases, the clinical and electrodiagnostic exams provided inadequate localization and severity data of the nerve injuries, and MRI was either precluded or provided no additional information. In each case, US disclosed focal nerve segment abnormalities, including regions of focal enlargement and nerve discontinuity with end-bulb neuroma, which guided surgical planning for nerve repair. The findings on US were subsequently confirmed intra-operatively. CONCLUSIONS: High resolution peripheral nerve US is a useful modality in assessment of combat-related PNI. Muscle Nerve, 2016 Muscle Nerve 54: 1139-1144, 2016.

Ethical considerations in elective amputation after traumatic peripheral nerve injuries.

Traumatic peripheral nerve injuries often complicate extremity trauma, and may cause substantial functional deficits. We have encountered patients who request amputation of such injured extremities, with the goal of prosthetic replacement as a means to restore function. Data on long-term outcomes of limb salvage vs amputation are limited and somewhat contradictory, leaving how to respond to such requests in the hands of the treating physician. We present example cases, drawn from our experience with wounded soldiers in a peripheral nerve injury clinic, in order to facilitate discussion of the ways in which these patients stress the system of medical decision-making while identifying ethical questions central to responding to these requests.

Diagnosis and treatment of somatoform disorders.

Many patients with somatoform disorders present to the neurology clinic, often after extensive evaluation that has left the patient and multiple other physicians frustrated. Knowledge of the typical characteristics of particular disorders enables the clinician to arrive at a positive diagnosis and facilitate referral to appropriate services. Using a series of representative cases, we review the DSM-IV-TR somatoform disorders most likely to present to the practicing neurologist, highlighting the epidemiologic features, typical presentations, and possible therapeutic approaches to each condition.