Biomedical subjects

P Sautot

Publications and source records attributed to P Sautot.

5 recordsLinked to original sources

PubMed1998

Computer-assisted spine surgery.

The aim of this study was to improve the reliability of pedicle screw insertion. Transpedicle screw insertion may cause neurological, vascular, and mechanical complications. Previous studies of surgical procedures have shown a significant rate of incorrect placement of the screw ranging from 10 to 40%. A new technique that combines preoperative computed tomography (CT) imaging with intraoperative passive navigation was used to perform 64 pedicle screw insertions in the thoracolumbar region. At the same time, 64 pedicle screw insertions were performed manually in the same region and on the same vertebral levels. Surgery was followed in all cases by postoperative radiographs and computed tomography examination, which allowed measurements of screw position relative to pedicle position to be performed. A comparison between the two groups showed that six screws in 64 vertebra (9%) had incorrect placement with the computer-assisted technique whereas 28 screws in 64 vertebra (44%) had incorrect placement with manual insertion. The intraoperative accuracy provided by the computer after registration was better than 1 mm. The good results obtained are similar to those reported in the literature. The cortex penetration observed with the computer-assisted technique was not imputed to computer failure. Errors by the surgeon in acquiring data in the pre- and perioperative steps may explain the six incorrect screw placements. This clinical experience confirms that the accuracy and the reliability of this computer-assisted technique are good.

Bone Screws↗

PubMed1998

Pedicle screw placement using image guided techniques.

Clinical evaluation of a computer assisted spine surgical system is presented. Eighty pedicle screws were inserted using computer assisted technology in thoracic and lumbar vertebrae for treatment of different types of disorders including fractures, spondylolisthesis, and scoliosis. Fifty-two patients with severe fractures, spondylolisthesis, or pseudoarthrosis of T10 to L5 were treated using a computer assisted technique on 1/2 the patients and performing the screw insertion manually for the other 1/2. At the same time, 28 pedicle screws were inserted in T12 to L4 vertebrae for scoliosis with the help of the computer assisted technique. Surgery was followed in all cases (66 vertebrae; 132 pedicle screws) by postoperative radiographs and computed tomographic examination, on which measurements of screw position relative to pedicle position could be done. For fractures, spondylolisthesis, or pseudarthrosis, comparison between the two groups showed that four screws in 52 (8%) vertebrae had incorrect placement with computer assisted technique whereas 22 screws in 52 (42%) vertebrae had incorrect placement with manual insertion. In patients with scoliosis, four screws in 28 (14%) vertebrae had incorrect placement. In all of the patients (132 pedicle screws) there were no neurologic complications. These results show that a computer assisted technique is much more accurate and safe than manual insertion.

Bone Screws↗

PubMed1997

Computer assisted spine surgery.

When inserting screws into a vertebral pedicle, the surgeon usually exposes the back part of the vertebra and uses his or her anatomic knowledge to align the drill in the proper direction. A slight error in direction may result in an important error in the position of the tip of the screw. This is done with no direct visibility of crucial structures (spinal cord, pleura, vessels). Statistical analysis of a series of surgical procedures has shown that 10% to 40% of the screws are not installed correctly. To reduce the risk of complication, a computer assisted method is proposed that enables the surgeon to place a screw at a position preoperatively defined in 3 dimensions using computed tomography images. This allows the surgeon to align a standard surgical drill with the optimal position and direction. The depth of the pilot hole during drilling also is monitored by the system to prevent penetration of the anterior cortex of the vertebral body. Using this procedure, in vitro tests were performed and showed that an accuracy of less than 1 mm can be obtained. Clinical trials were done in 10 patients who suffered severe scoliosis or spondylolisthesis. The trajectory of the holes drilled in L2, L3, L4, and L5 vertebrae were checked for all clinical tests. Postoperative radiographs and computed tomography scans showed that the screws were well inserted in each plane for each pedicle. This technique also can be used to perform osteosynthesis at the thoracic and cervical levels.

Adult↗

PubMed1995

Computer-assisted dental implant surgery using computed tomography.

Standard planning for dental implants consists of a prosthesis simulation on diagnostic casts and radiographic examination of anatomical structures. The clinician visually locates the planned trajectory on the surgical site in the patient's mouth without direct correlation between the radiographs and the anatomy. We have developed a computer assisted technique to define the optimal position of the bone implant using computed tomography to accurately place the implant in the planned position using a guide drilled into a resin splint.

Computer Simulation↗

PubMed1995

Computer-assisted spine surgery: a technique for accurate transpedicular screw fixation using CT data and a 3-D optical localizer.

The computer-assisted spine surgery system presented in this paper follows the basic ideas which have been developed for computer-assisted medical interventions (CAMI) in our lab since 1985. There are three steps to insert a linear tool inside vertebral pedicles. First, the surgeon defines an optimal trajectory on pre-operative computed tomography. Second, this trajectory is reported in the operating room coordinate system using an intra-operative sensor and a registration algorithm. Third, a guiding system helps the surgeon follow the selected trajectory. In this paper, we present an implementation of this method that uses only a 3-dimensional optical localizer. Results on cadaver specimens and on the first seven patients are presented.

Bone Screws↗