[Intraoperative ultrasound study of thoracolumbar spinal fractures with spinal canal fragments. Determining canal width and anatomic control of decompression: comparative analysis with CT].

Intraoperative ultrasonography is recommended for operations on the thoracolumbar spine to complement the information provided by standard X-ray, intensifier screen or myelography. There are no unanimates opinions concerning the impaction or exeresis of these fragments. The aim of this study was to show the advantages of intraoperative ultrasonography for anatomic determination and control of the maneuvers used. This study included 46 cases with fractures from T11 to L2. Ultrasonography was performed during the intraoperative reduction provided by the installation and the pedicular instruments. The authors stress the limits of the anatomic and geographic determination, as well as tilting of the fragments because of the size of the ultrasonographic head. The quality of the exeresis may be falsely interpreted in the presence of fragments with a section of less than 4 mm, lateralized, double fragments or in the presence of massive intraoperative haemorrhage. Analysis of the impaction results is more complicated because all of these fragments displaced themselves secondarily. The ligamentum communis vertebralis posterior has no anatomical containing role. The tilting before the impaction and the state of the overlying intervertebral disk represent essential factors for failures. Ultrasonography is better than intraoperative myelography. Nevertheless, it still needs to be complemented by intraoperative profile X-rays and a very precise preoperative CT scan of the intervertebral disk lesions analysis of complicated cases (fragments with residual pedicular attachments--type A 3.1.2.; T-like fractures--type A 3.2.1.).