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Biomedical subjects

J Tonetti

Publications and source records attributed to J Tonetti.

14 recordsLinked to original sources
PubMed2005

Morphological cervical disc analysis applied to traumatic and degenerative lesions.

Trauma and degenerative pathologies at the lower cervical spine are different from lumbar spine pathologies. However, the description of cervical discs is classically taught similarly to that of the lumbar discs. Recent studies have raised this issue, and in 1999, Mercer and Bogduk described ventral annulus fibrosus as a crescent-shaped interosseous ligament. We propose a metric analysis of the different components of the cervical disc to examine this description. We analyzed 140 sagittal and coronal transections of 35 discs. These discs were taken from seven cervical spines at the five lower levels, C2-C3, C3-C4, C4-C5, C5-C6 and C6-C7. We measured quantitative parameters on sagittal, para-sagittal, ventral coronal and dorsal coronal colored transections: disc length (L), ventral annulus thickness (VAF), lateral annulus thickness (LAF), dorsal annulus thickness (DAF), length of the fibrocartilaginous tissue (FC), sagittal and coronal fibrocartilaginous core ratio (% Core) and intra-disc cleft length (Cleft). We also measured two qualitative parameters: degenerative disease of cartilaginous end plates and total intra-disc cleft. Finally, we examined 114 transections, and 18.5% were ruled out. The results showed thick ventral annulus fibrosus, thin lateral annulus and a very thin dorsal annulus. Fibrocartilaginous tissue filled the dorsal sagittal half of the disc. Intra-disc cleft split the fibrocartilaginous tissue and spread through the ventral annulus only six times. The shape of the ventral annulus at the lower cervical spine is compared to a pivot-hinge device. The aspect is functionally discussed in regard to teardrop fractures, unilateral locked facet syndrome and degenerative changes in the unco-vertebral area.

Aged↗
PubMed2004

[Neurological damage in pelvic injuries: a continuous prospective series of 50 pelvic injuries treated with an iliosacral lag screw].

PURPOSE OF THE STUDY: The purpose of this study was to analyze lesions to the lumbosacral plexus related to pelvic injury and its treatment. MATERIAL AND METHODS: Forty-four patients presented 50 posterior osteoligamentary lesions of the pelvic girdle. All patients except eight had other injuries. Mean ISS was 27/75. Posterior lesions were: iliosacral disjunction (n=23), extra-foraminal fracture of the sacrum (n=4), transforaminal fracture (n=22), intra-foraminal fracture (n=1). Vertical posterior displacement was > 1 cm for 24 posterior lesions. Orthopedic reduction was performed at admission for all patients. Fluoroscopy-guided percutaneous lag screw fixation was performed in all cases, on the average eight days after the accident. Neurological involvement was evaluated at admission, after surgery, and at last follow-up. Data were recorded for skeletal muscles, lower limb dermatomes, tendon reflexes, and anal tone. Screw emplacement was checked on the CT-scan. Outcome was assessed subjectively with the Majeed score, a self-administered visual analog scale, and use of antalgesic drugs according to the WHO classification. RESULTS: The neurological examination could not be performed for ten patients at admission. Postoperatively, there was a neurological deficit associated with 26 osteoligamentary lesions (23 lesions of the lumbosacral trunk, 14 lesions of the S1 spinal nerve, 3 lesions of the pudendal nerve, 12 lesions of the superior gluteal nerve, and 10 lesions of the femoral nerve). Patients with neurological involvement had experienced more severe trauma. The iliosacral screw was partially extra-osseous in thirteen cases, with an associated iatrogenic neurological deficit in seven. At mean follow-up of 20 Months (range 4-50) there persisted ten major sequelae including eight cases of hallux extensor deficit. DISCUSSION: Neurological involvement is underestimated during the acute phase of trauma. After recovery, only the manifestations of major injuries persist. The prognosis is poor in the event of a stretched lumbosacral trunk or gluteal nerve due to iliosacral disjunction. Prognosis is good for nerve contusion due to sacral fracture because of early reduction. The femoral nerve is generally injured by compression due to a peri-fracture hematoma; recovery is the rule. Iliosacral screwing requires rigorous technique by a skilled and experienced surgeon. CONCLUSION: About 52% of posterior osteoligamentary injuries are associated with neurological symptoms. After recovery, permanent deficit persists in 21.7%. The most common sequelae are hallux extensor and gluteus medius palsy due to stretching of the lumbosacral trunk.

Adolescent↗
PubMed2001

Clinical results of percutaneous pelvic surgery. Computer assisted surgery using ultrasound compared to standard fluoroscopy.

This study presents early results of clinical experience with the application of Computer Assisted Surgery (CAS) to percutaneous iliosacral screwing, with comparison to a historical series of patients treated using percutaneous fluoroscopy. Four patients were instrumented using a CAS system, with 10 screws being inserted. Thirty patients were treated by percutaneous fluoroscopic screwing, with 51 screws being inserted. The follow-up assessment included the following criteria; operative time, parameters of radiation exposure, neurological examination, screw placement evaluation on CT-scan, antalgic drug consumption, pain, Majeed grading, and loosening of implants. In the CAS group, the average radiation time was 0.35 min per patient and 0.14 min per screw. No trajectories outside the bone and no postoperative neurological deficits were found. In the fluoroscopic group, the average radiation time was 1.03 min per patient and 0.6 min per screw. Twelve screws had outside-bone trajectories, and iatrogenic neurological deficits were found in seven patients. The average operative time was 50 min in the CAS group and 35 min in the fluoroscopic group. The present CAS technique shows better placement of iliosacral screws, with no outside-bone trajectories and lower radiation exposure.

Adult↗
PubMed2001

Clinical validation of computer assisted pelvic surgery using ultrasound. A percutaneous safe technique with low radiation exposure.

This study presents early results of the clinical experience of computer assisted surgery (CAS) applied to percutaneous iliosacral screwing. The results of these 10 first cases (4 patients) are compared to an historical series of 51 cases (30 patients). The CAS technique shows better screw placement without outside bone screw and a very low radiation exposure.

Adolescent↗
PubMed2000

[Implantation of iliosacral screws. Simulation of optimal placement by 3-dimensional X-ray computed tomography].

PURPOSE OF THE STUDY: Percutaneous iliosacral screws are used advantageously to fix unstable pelvic girdle avoiding the morbidity of open access for conventional screw fixation. The insertion technique must be precise due to the risk of injury to the lumbosacral nerve trunk, the cauda equina roots, and the first sacral nerve. We undertook a study of the implantation site of iliosacral screws looking for a means of standardizing the drilling procedure on the basis of 3D computed tomography (CT) data. MATERIAL AND METHODS: A CT series with 3D reconstruction was performed on 11 pelvis bones. We retained pelvis parameters and characterized the axis and narrow zone of the sacral wing. The insertion routes of 6.5 mm cancelous bone screws were simulated: two iliosacral routes fixing S1, and two iliosacroiliac routes fixing S1 and S2. The values of the pelvic parameters and the positions of the screws were compared with the Spearman correlation test and graphic regression. RESULTS: The pelvic incidence was a mean 47 degrees. The length of the sacral wing was a mean 73 mm. The narrow zone of the wing was 47 mm from the lateral iliac fossa. In the narrow zone, the wing section showed an oval shape: 22 mm largest diameter, 11 mm smallest diameter. The wing was oriented 84 degrees in the paracoronal plane perpendicular to the plane of the sacral plate, 67 degrees in the para-axial plane parallel to the sacral plate, and 37 degrees in the sagittal plane of the subject. The length of the upper S1 screw was a mean 80 mm. This upper screw was inclined 89 degrees in the para-coronal plant, 61 degrees in the para-axial plane and 28 degrees in the sagittal plane. The length of the lower S1 screw as a mean 80 mm. This lower screw was inclined 74 degrees in the para-coronal plane, 91 degrees in the para-axial plane and 110 degrees in the sagittal plane. The fixation screws could be inserted in 12 out of 22 cases. Correlations were found with height of the subject, length of the wing and the screw, and screw inclination. The inclination of the upper S1 screw in the para-coronal plane was correlated with the larger diameter of the sacral wing. DISCUSSION: The pelvis parameters measured were comparable with data in the literature. The very small dimensions of the narrow zone dictate a very precise drilling for the narrow zone. This narrow zone determines the inclination of the screw insertion. In the sagittal plane the standard deviation was very large making it impossible to interpret the data. The route of the upper screw runs obliquely forward in the plane parallel to the sacral plate. The lower screw runs upwardly in the plane perpendicular to the sacral plate. It does not appear possible to insert fixation screws in a routine procedure. Preoperative assessment would be necessary before percutaneous insertion. CONCLUSION: The 3D CT reconstructions of the sacral wing can be used to determine the precise optimal position of the two iliosacral screws. The principle orientations can be deducted from the plane of the sacral plate. Approximate indications can help reduce operative time and exposure to irradiation (patient and surgeon). Percutaneous iliosacroiliac screw fixation cannot be proposed for all patients.

Adult↗
PubMed1999

Elastic reinforcement and thickness of the joint capsules of the lower cervical spine.

Mechanical studies have shown the major strength of the joint capsules of the lower cervical spine, especially in its ventrolateral part. The aim of this study was to examine the structure of the joint capsules in order to discover if there is a correspondence between biomechanical properties and descriptive anatomy. Ten transverse sections and 4 sagittal sections obtained from 6 cadavers were observed under light microscopy at X 25 to X 250 magnification. Standard stains and specific elastic fiber stain were used for histologic preparation. The data were the thickness of the joint capsules in the different quadrants, and the topography and direction of the elastic fibers. The results showed that the ventrolateral part of the joint capsules is thick and reinforced by oblique elastic fibers. The dorsal part is thin. The authors suggest that the descriptive anatomy of the joint capsules confirms their mechanical properties. They note that the role of the ventrolateral part is supplemented by that of the posterior longitudinal ligament for the stability of the functional cervical spinal unit.

Aged↗
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

[Computer-assisted surgery: automated screw placement in the vertebral pedicle].

AIM OF THE STUDY: Previous studies of conventional surgical procedures have shown a significant rate of incorrect pedicle screw placement ranging from 10 to 40%. Transpedicle screw insertion may cause three types of complications: neurologic, vascular and mechanical. The aim of this prospective study is to improve the reliability of pedicle screwing with computer assistance. MATERIAL AND METHODS: A new and original technique that combines preoperative computed tomography imaging with intraoperative passive navigation has been used to perform 48 pedicle screwings in the thoracolumbar region. In the same time, 48 pedicle screwings were performed manually in the same region and on the same vertebral levels. With postoperative X-rays and computed tomography examination, screw position related to pedicle position could be assessed and comparison could be made between the two groups (with and without computer assistance). RESULTS: Two screws in 48 vertebra (4%) had incorrect placement with computer assisted technique whereas 18 screws in 48 vertebra (37%) had incorrect placement with manual insertion. The intraoperative accuracy provided by the computer after registration was better than 1 mm. The difference between the two groups was statistically highly significant (P < 0.0001). The cortex penetration observed with the computer assisted technique was not imputed to computer failures. Errors in acquiring data by the surgeon in the pre and peroperative steps may explain the two incorrect placements of the screws. CONCLUSION: This clinical experience confirms that the accuracy and reliability of this computer assisted technique are very 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↗
PubMed1998

Percutaneous iliosacral screw placement using image guided techniques.

A computer assisted technique of iliosacral screw placement that is applicable to unstable pelvic ring fractures is proposed. The goals are to operate noninvasively with a percutaneous procedure to decrease the complications of surgical exposure and to provide greater accuracy in locating the close neurovascular structures. Preoperative computed tomographic images of the pelvis are provided and a computed tomography three-dimensional model is built. In this model, the optimal trajectories for the drilling are planned. An ultrasound based registration is performed intraoperatively. This registration is the most original part of this work. After performing the passive drilling guidance step, the surgeon places the screws. The accuracy of the ultrasound based registration is checked by comparison with a standard surface based registration at the end of the test experiment. Each screw position is verified by a computed tomographic examination. Four human anatomic specimen pelves were tested with three screw insertions for each pelvis (12 screws). All of the screws were considered to be placed correctly. The method is safe and encourages the start of clinical application.

Bone Screws↗
PubMed1998

Feasibility of orthopaedic teleconsulting in a geriatric rehabilitation service.

Fifteen elderly patients participated in a teleconsultation with an orthopaedic surgeon, which was then followed by a conventional, face-to-face consultation. The comparison between the surgeon's ratings for both types of consultation suggested that the telemedicine consultation was satisfactory in terms of the quality of image and sound, the clinical examination and general simplicity. The telemedicine consultations did not generate a need for any additional clinical investigations, although in two cases a face-to-face consultation was necessary to clarify clinical signs (shortening of a limb and scar tissue). The surgeon's rating of his decision level was superior in the face-to-face situation in four cases, and for 11 patients it was equal. Similarly, the surgeon's level of confidence in decision making was superior in the conventional situation for five patients and equal for 10 patients. Patient attitudes towards teleconsulting were favourable. There was a high level of patient satisfaction. Teleconsulting between orthopaedic surgeons and elderly patients therefore appears to be possible, provided that certain technical, clinical and psychological considerations are addressed.

Aged↗
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↗
PubMed1997

[Proximal femoral fractures in patients over 75 years. Vital and functional prognosis of a cohort of 78 patients followed during 2.5 years].

PURPOSE OF THE STUDY: The purpose of this study was to highlight factors influencing vital and functional prognosis at 2.5 years of elderly people being treated for a proximal femoral fracture. MATERIAL: The study was based on 78 patients more than 75 years old admitted to the orthopedic department for emergency treatment. After post-operative care, patients were transferred to a geriatric readaptation unit. The average patient age at the time of surgery was 85 years. METHODS: This was a retrospective study. Survival graphs were established for the entire population as well as for the sub-populations characterized by a studied parameter. Mortality factors were compared via a univariable analysis. A multivariable logistical regression analysis isolated the factors explaining mortality at 12, 18, and 30 months and survival at 30 months, as well as factors explaining functional prognosis at 1 year. RESULTS: The overall mortality rate was 41 per cent, 48.5 per cent of deaths occur within the first year. Factors which are harmful for vital prognosis are the following: high degree of dependence before the fracture, the existence of a neuropsychiatric pathology, and age factor (more than 85 years). 61.5 per cent of surviving patients were independent for daily activities. 77 per cent of surviving patients lived in their usual place of residence. Factors which were harmful for functional prognosis were the following: type of the fall, symptomatic of an underlying pathological state, and existence of a neuropsychiatric pathology. Nutrition was also a predictive factor concerning the patient's out come. DISCUSSION: The average age of the studied population was higher than in most studies in literature. The treatment is mainly based on hip arthroplasty. The group of patients of over 85 have the highest mortality rate. However, a better survival rate at 18 months has been observed for patients older than 90 years. The delay before surgical care was significantly negative if longer than 6 days. However, a delay of 3 to 6 days was not significantly harmful for survival. Within the studied population, the maximum autonomy gain was observed during the first 6 months. The type of non-accidental fall, symptomatic of an associated pathology, was a factor for functional prognosis which has not been often mentioned. So was the biological deficit of nutrition. Social status acted as an indicator of functional status evolution. CONCLUSION: Therapeutic choices can only be guided by assessments of patients' vital and functional prognosis. A sophisticated or even expensive device should be demanded for patients with favorable prognosis. For patients with precarious functional and vital prognosis, priority should be given to less invasive techniques with immediate walking. The cost of the device should be correlated with patient's functional investment.

Age Factors↗