Browsing by Subject "sciatic nerve"

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    Acute Peroneal Neuropathy and Foot Drop in Two Adolescent Female Athletes with New-Onset Diabetes
    (Wolters Kluwer, 2022-02) Jaeger, Joel A.; Gohil, Anisha; Nebesio, Todd D.; Pediatrics, School of Medicine
    The common peroneal nerve is derived from the sciatic nerve. It travels superficially along the lateral aspect of the knee near the fibular head where it bifurcates into the superficial and deep peroneal nerves. These nerves also provide sensation to the lateral lower leg and dorsal foot. The superficial and deep peroneal nerves innervate the muscles of the lateral lower leg and anterior lower leg compartments, respectively. Loss of the soft tissue and subcutaneous fat pad that surrounds and cushions the peroneal nerve near the fibular head leaves it susceptible to injury (1). This can affect the common peroneal nerve or either of its two branches, the deep or superficial peroneal nerves (2). Damage to the nerve by stretching or compression may result in loss of sensation and motor function, resulting in foot drop (3). Acute peroneal neuropathy in the context of rapid weight loss (also known as “slimmer's paralysis”) has been reported in prisoners of war, extreme dieting, and after bariatric surgery (2,4). It also is more common in individuals who habitually cross their legs (2). While seen less commonly than in adults, acute peroneal neuropathy also has been reported in children and adolescents (5). Etiologies in this age group include direct trauma, entrapment from bone tumors, compression from casting, and rapid weight loss (5,6). Causes of sudden and quick weight loss may be due to crash dieting and anorexia nervosa (6). There also are rare reports of slimmer's paralysis being caused by rapid weight loss from untreated type 1 diabetes (7,8). In this report, we present two active adolescent female athletes who presented with ankle pain or weakness that was ultimately due to acute peroneal nerve neuropathy associated with substantial and fast weight loss from undiagnosed type 1 diabetes.
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    A Comparative Analysis of Local and Global Peripheral Nerve Mechanical Properties During Cyclical Tensile Testing
    (2022-05) Doering, Onna Marie; Yoshida, Ken; Wallace, Joseph; Goodwill, Adam
    Understanding the mechanical properties of peripheral nerves is essential for chronically implanted device design. The work in this thesis aimed to understand the relationship between local deformation responses to global strain changes in peripheral nerves. A custom-built mechanical testing rig and sample holder enabled an improved cyclical uniaxial tensile testing environment on rabbit sciatic nerves (N=5). A speckle was placed on the surface of the nerve and recorded with a microscope camera to track local deformations. The development of a semi-automated digital image processing algorithm systematically measured local speckle dimension and nerve diameter changes. Combined with the measured force response, local and global strain values constructed a stress-strain relationship and corresponding elastic modulus. Preliminary exploration of models such as Fung and 2-Term Mooney-Rivlin confirmed the hyperelastic nature of the nerve. The results of strain analysis show that, on average, local strain levels were approximately five times smaller than globally measured strains; however, the relationship was dependent on global strain magnitude. Elastic modulus values corresponding to ~9% global strains were 2.070 ± 1.020 MPa globally and 10.15 ± 4 MPa locally. Elastic modulus values corresponding to ~6% global strains were 0.173 ± 0.091 MPa globally and 1.030 ± 0.532 MPa locally.
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    Double p52Shc/p46Shc Rat Knockout Demonstrates Severe Gait Abnormalities Accompanied by Dilated Cardiomyopathy
    (MDPI, 2021) Miller, Bradley; Kostrominova, Tatiana Y.; Geurts, Aron M.; Sorokin, Andrey; Anatomy and Cell Biology, School of Medicine
    The ubiquitously expressed adaptor protein Shc exists in three isoforms p46Shc, p52Shc, and p66Shc, which execute distinctly different actions in cells. The role of p46Shc is insufficiently studied, and the purpose of this study was to further investigate its functional significance. We developed unique rat mutants lacking p52Shc and p46Shc isoforms (p52Shc/46Shc-KO) and carried out histological analysis of skeletal and cardiac muscle of parental and genetically modified rats with impaired gait. p52Shc/46Shc-KO rats demonstrate severe functional abnormalities associated with impaired gait. Our analysis of p52Shc/46Shc-KO rat axons and myelin sheets in cross-sections of the sciatic nerve revealed the presence of significant anomalies. Based on the lack of skeletal muscle fiber atrophy and the presence of sciatic nerve abnormalities, we suggest that the impaired gait in p52Shc/46Shc-KO rats might be due to the sensory feedback from active muscle to the brain locomotor centers. The lack of dystrophin in some heart muscle fibers reflects damage due to dilated cardiomyopathy. Since rats with only p52Shc knockout do not display the phenotype of p52Shc/p46Shc-KO, abnormal locomotion is likely to be caused by p46Shc deletion. Our data suggest a previously unknown role of 46Shc actions and signaling in regulation of gait.
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    A novel method for sciatic nerve decompression: Cadaveric feasibility study with potential application to patients with piriformis syndrome
    (Elsevier, 2015-12) Tubbs, Richard Isaiah; Barton, James C., III; Watson, Caroline C.; Kollias, Theofanis; Ward, Robert J.; Loukas, Marios; Barbaro, Nicholas M.; Cohen-Gadol, Aaron A.; Department of Neurological Surgery, IU School of Medicine
    Introduction Approaches for proximal sciatic nerve decompression use a transgluteal route, but are associated with morbidity and complications. An alternative anterior approach to the sciatic nerve was designed. Methods Five adult human cadavers (10 sides) were used. In the supine position and with lower limbs abducted, an incision was made 3-cm inferolateral to the pubic tubercle of each specimen. With blunt dissection, a muscle-splitting approach through the obturator foramen was performed through the underlying adductor muscles and deeper obturator muscles that traversed the obturator foramen. Within the pelvis, a laparoscope was inserted in the surgical corridor, which was extraperitoneal. The obturator neurovascular bundle was identified medially and followed posterolaterally toward the greater sciatic foramen. The sciatic nerve was identified. The piriformis muscle was identified as it exited the greater sciatic foramen. Microscissors were inserted and under visualization with the laparoscope, the piriformis muscle was transected near the spine. Results The piriformis was well visualized and transected. The muscle was best visualized inferolateral to the sciatic nerve. No gross damage to the sciatic nerve or surrounding neurovascular structures occurred. Mean distance from the superomedial edge of the obturator foramen to the ischial spine was 7.2 cm for left sides and 7.3 cm for right sides. Conclusions Use of a laparoscope to approach the piriformis muscle from an anterior intrapelvic, extraperitoneal approach via the obturator foramen is feasible. Clinical use of this method is in order to demonstrate use in patients with suspected compression of the sciatic nerve by the piriformis muscle.