Osteogénesis mediante técnicas de regeneración tisular guiada en defectos de hueso largo

La regeneración ósea guiada consiste en el empleo de una membrana tubular que rodea un defecto óseo, que mantiene los tejidos blandos circundantes fuera del defecto, creando un espacio cerrado con elevada densidad de elementos osteogénicos. La validez del uso de aloinjertos aórticos criopreservados como membranas de regeneración ósea guiada fue puesta de manifiesto con anterioridad por nuestro grupo investigador en defectos de radio de conejo. Esta tesis doctoral parte de la hipótesis de que la arteria funciona favoreciendo la regeneración ósea no sólo por un mecanismo de barrera sino que determinados elementos celulares a nivel de su pared podrían participar de forma activa en el proceso reparador del hueso, de forma análoga a los procesos de calcificación en el seno de la placa aterosclerótica. Para ello, se ha evaluado la capacidad de calcificación de la aorta torácica de conejo in vivo y se ha estudiado la pared arterial de aortas fresca y criopreservada descongelada mediante técnicas de cultivo celular e inmunocitoquímica, así como la disposición espacial de las células obtenidas mediante técnicas de microscopía electrónica de transmisión y barrido, y su capacidad de experimentar calcificación. Para evaluar la capacidad de regeneración ósea guiada de la arteria frente a otras membranas, se ha hecho un estudio comparativo de aorta criopreservada descongelada frente a membranas sintéticas de PTFEe (patrón oro en regeneración ósea guiada) en el tratamiento de defectos de radio de conejo, mediante técnicas de imagen, microscopía óptica y microscopía electrónica de transmisión. Con el objetivo de determinar las posibles ventajas de la arteria desde el punto de vista estructural se ha hecho un estudio comparativo entre aloinjertos aórticos criopreservados y membranas de PTFEe mediante técnicas de microscopía electrónica

Stoppa approach for intrapelvic damage control and reconstruction of complex acetabular defects with intra-pelvic socket migration: A case report

Introduction: Failed hip arthroplasty with intrapelvic acetabular migration can be challenging due to the potential damage of intrapelvic structures. Presentation of the case: We present a case of a 75 year-old lady with failed hip arthroplasty with loosening of implants and intra-pelvic migration of the cup, antiprotrusio cage mesh, screws and plate. A modified Stoppa approach was performed, a part of the migrated elements were safely removed, the intrapelvic structures were controlled, and the bone defect was reconstructed through the Stoppa approach combined with the lateral window of ilioinguinal approach by means of bone struts and metallic plates, which is a novel technique. Then an extended posterolateral hip approach was done and the acetabulum was reconstructed using porous tantalum augments and morselized allograft. A cemented constrained socket was implanted. After one-year follow-up the patient is able to walk with one crutch without pain. Discussion: Due to intrapelvic migration, the implants used in hip arthroplasty may become entrapped between the anatomical structures lodged in the pelvis and cause damage to them. A careful preoperative assessment and planning are mandatory. A migrated socket can be inaccessible through a conventional hip approach and removal could be very difficult and dangerous. Conclusion: The Stoppa approach in hip revision surgery can be a complement to traditional approaches to control the intrapelvic structures, remove migrated implants of previous surgery and reconstruct the pelvic defect

Traction injury of the brachial plexus confused with nerve injury due to interscalene brachial block: A case report

Introduction: Shoulder surgery is often performed with the patient in the so called “beach-chair position” with elevation of the upper part of the body. The anesthetic procedure can be general anesthesia and/or regional block, usually interscalenic brachial plexus block. We present a case of brachial plexus palsy with a possible mechanism of traction based on the electromyographic and clinical findings, although a possible contribution of nerve block cannot be excluded. Presentation of the case: We present a case of a 62 year-old female, that suffered from shoulder fracture-dislocation. Open reduction and internal fixation were performed in the so-called “beach-chair” position, under combined general-regional anesthesia. In the postoperative period complete motor brachial plexus palsy appeared, with neuropathic pain. Conservative treatment included analgesic drugs, neuromodulators, B-vitamin complex and physiotherapy. Spontaneous recovery appeared at 11 months. Discusion: in shoulder surgery, there may be complications related to both anesthetic technique and patient positioning/surgical maneuvers. Regional block often acts as a confusing factor when neurologic damage appears after surgery. Intraoperative maneuvers may cause eventual traction of the brachial plexus, and may be favored by the fixed position of the head using the accessory of the operating table in the beach-chair position. Conclusion: When postoperative brachial plexus palsy appears, nerve block is a confusing factor that tends to be attributed as the cause of palsy by the orthopedic surgeon. The beach chair position may predispose brachial plexus traction injury. The head and neck position should be regularly checked during long procedures, as intraoperative maneuvers may cause eventual traction of the brachial plexus