Annales de chirurgie
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Annales de chirurgie · Jan 1996
[A study of biomechanical coupling between spine and rib cage in the treatment by orthosis of scoliosis].
Orthoses are widely used to treat scoliotic deformities of the trunk, but the way the corrective forces are transmitted from the thorax to the spine remains not well understood, and several undesired effects such as the reduction of sagittal curvatures or weak derotations are often reported. A biomechanical finite element model of the trunk was used to investigate the hypothesis that there exist coupling mechanisms between the scoliotic spine and rib cage which may explain incomplete and unexpected results obtained by orthotic treatments. Forces of 40 N were applied on the rib hump and on the lateral side of the thorax, and their individual effects were evaluated in 3-D on the spine and thorax using several geometrical indices (transverse plane translations, axial, sagittal and frontal rotations, Cobb angles). ⋯ Based on the results found in this study, a simple and more optimal approach to treat scoliotic deformities was proposed and consisted to apply loads laterally on the convex side and on the anterior thorax opposite to the rib hump, with a system that mechanically constrains the posterior rib hump to move backward. It was simulated on 4 scoliotic patients presenting thoracic curves between 22 degrees and 54 degrees to evaluate its practicability and it was found that derotation of the trunk (between 7 degrees and 13 degrees) and reduction of frontal curvatures (up to 4 degrees) could be done without reducing physiological sagittal curvatures. More simulations on different scoliotic configurations are necessary to find the most optimal combination of forces to produce a real 3-D correction of scoliotic deformities.
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Annales de chirurgie · Jan 1996
[Damage to the inguino-femoral nerves in the treatment of hernias. An anatomical hazard of traditional and laparoscopic techniques].
Laparoscopic techniques currently constitute an alternative proposed for the repair of hernias of the inguinofemoral region. Nerve injuries have led some teams to recommend technical principles based on the anatomical relations of these nerves with the subperitoneal fascia transversalis and inguinal fossae. An anatomical study consisting of dissection of nonembalmed cadavres, allowed, after evisceration, dissection of the lumbar plexus and its terminal branches, particularly those supplying the inguinofemoral region: iliohypogastric and ilio-inguinal nerves, the genitofemoral nerve, the femoral nerve and the lateral cutaneous nerve of the thigh. ⋯ Installation of an abdominal wall prosthesis, either transperitoneally or retroperitoneally, must be centered on the deep inguinal ring, and its solid sutures are located medially to the pectineal ligament and anterior abdominal wall. On the other hand, the nerves at risk of being damaged are situated laterally: the ilio-inguinal and ilio-hypogastric nerves in the plane between external oblique and internal oblique above the anterior superior iliac spine, lateral cutaneous nerve of the thigh under the inguinal ligament close to the anterior superior iliac spine, genitofemoral nerve with the spermatic cord in the deep inguinal ring and femoral nerve underneath the inguinal ligament with the psoas muscle lateral to the external iliac artery. No stapling must be performed under the plane of the inguinal ligament to avoid damage to the femoral vessels and lateral to the deep inguinal ring to avoid nerve damage.