Adult brachial plexus injuries frequently lead to significant and permanent physical disabilities. Investigating the mechanism of the injury using biomechanical approaches may lead to further knowledge with regard to preventing brachial plexus injuries. However, there are no reports of biomechanical studies of brachial plexus injuries till date. Therefore, the present study used a complex three-dimensional finite element model (3D-FEM) of the brachial plexus to analyze the mechanism of brachial plexus injury and to assess the validity of the model. A complex 3D-FEM of the spinal column, dura mater, spinal nerve root, brachial plexus, rib bone and cartilage, clavicle, scapula, and humerus were conducted. Stress was applied to the model based on the mechanisms of clinically reported brachial plexus injuries: Retroflexion of the cervical, lateroflexion of the cervical, rotation of the cervical, and abduction of the upper limb. The present study analyzed the distribution and strength of strain applied to the brachial plexus during each motion. When the cervical was retroflexed or lateroflexed, the strain was focused on the C5 nerve root and the upper trunk of the brachial plexus. When the upper limb was abducted, strain was focused on the C7 and C8 nerve roots and the lower trunk of the brachial plexus. The results of brachial plexus injury mechanism corresponded with clinical findings that demonstrated the validity of this model. The results of the present study hypothesized that the model has a future potential for analyzing pathological conditions of brachial plexus injuries and other injuries or diseases, including that of spine and spinal nerve root.
Background: Reconstruction after wide resection of a malignant musculoskeletal tumor is challenging. We performed biological reconstruction with an extracorporeally-irradiated autograft in combination with a vascularized bone graft. Patients and Methods: Fifteen patients who underwent curative resection of malignant musculoskeletal tumor followed by reconstruction with this method were included. Oncological outcomes, survival of the graft, radiological findings and functional outcomes were reviewed. Results: No local recurrences were detected from the irradiated bones, and 93% of the vascularized bone grafts survived. The mean MSTS score was 24.8 in all cases, 22.9 in the osteoarticular cases, and 27 in the intercalary cases. The intercalary tibia cases showed excellent results with a mean MSTS score of 29.3. Conclusion: This method has the advantage of combining the mechanical quality of an irradiated autograft and biological quality of a vascularized bone graft. The best indication of this method is for intercalary defects of the tibia.Reconstruction of massive bony defects following wide resection of a malignant musculoskeletal tumor is challenging in many cases. Several procedures are available for reconstruction and mega-prosthesis is one of the useful reconstructive tools. However, the relative high rate of complications, limited durability and limited joints may be weak points of the mega-prosthesis. Since this disease is common in the young population, appropriate prostheses are not always available in all cases. While a tailor-made prosthesis may be the solution for such cases, making the prosthesis at the point of operation planning may limit the procedure of wide resection during operation. Wide resection with adequate margin must be performed without any inconvenience during the operation. For these reasons, we performed complete biological reconstruction using extracorporeally-irradiated bone autografts for reconstruction after wide resection, in cases in which no proper prosthesis has been available.Extracorporeal irradiation and re-implantation of a tumor bone was first described by Spira and Lubin in 1968 (1). Since then, several reports have shown excellent local control of the tumor and acceptable to good functional results using irradiated autografts (2-4). However, since the irradiated autografts have no blood supply, serious problems, such as nonunion, infection, fracture and bone absorption, remain. To solve these problems, we utilized the combined use of irradiated autografts with a vascularized bone graft.A vascularized bone graft is a living bone with plenty of blood supply. It is safe and reliable to use vascularized bone graft to reconstruct segmental skeletal defects due to several causes, such as severe trauma (5, 6), resection of malignant tumors or infection. Vascularized bone grafts are expected to provide vascularity and mechanical stability. However, when vascularized bone grafts are used alone, some major issues, such as inadequate adaptation for the recipient site and late fat...
Promoting bone healing after a fracture has been a frequent subject of research. Recently, sclerostin antibody (Scl-Ab) has been introduced as a new anabolic agent for the treatment of osteoporosis. Scl-Ab activates the canonical Wnt (cWnt)-β-catenin pathway, leading to an increase in bone formation and decrease in bone resorption. Because of its rich osteogenic effects, preclinically, Scl-Ab has shown positive effects on bone healing in rodent models; researchers have reported an increase in bone mass, mechanical strength, histological bone formation, total mineralized callus volume, bone mineral density, neovascularization, proliferating cell nuclear antigen score, and bone morphogenic protein expression at the fracture site after Scl-Ab administration. In addition, in a rat critical-size femoral-defect model, the Scl-Ab-treated group demonstrated a higher bone healing rate. On the other hand, two clinical reports have researched Scl-Ab in bone healing and failed to show positive effects in the femur and tibia. This review discusses why Scl-Ab appears to be effective in animal models of fracture healing and not in clinical cases.
Objective: Schwannomas are the most common type of neoplasm of the peripheral nerves. Enucleation is a standard surgical procedure; however, it occasionally results in iatrogenic nerve injury, even with atraumatic procedures. Herein, we present the clinical characteristics of schwannoma arising in the extremities and discuss the clinical outcomes of extra-and intra-capsular enucleation.Patients and Methods: We reviewed 122 schwannomas treated at our institute. Schwannomas arising from the minor nerve (n=30) or intramuscularly (n=15) were operated using the extra-capsular technique. Of the 77 major nerve schwannomas, 62 schwannomas were treated using the intra-capsular technique and 15 schwannomas using the extra-capsular technique. Results: Neurological deficits following enucleation were significantly lower using the intra-capsular technique than with the extra-capsular technique. The patient age, duration of symptoms, maximum tumor diameter, and site of occurrence were not associated with subsequent neurological deficits. With both techniques, no tumor recurrence was observed at the final follow-up. Conclusion:These results support the use of intra-capsular micro-enucleation as a safe and reliable treatment for every type of schwannoma. To minimize the risk of nerve injury, en bloc resection should not be used because the main purpose of schwannoma surgery is the relief of symptoms, not tumor resection.
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