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Biomedical subjects

B Jeanneret

Publications and source records attributed to B Jeanneret.

At least 19 recordsLinked to original sources
PubMed2002

[Pediatric spinal injuries].

Spine injuries during growth are rare, but in comparison to adults they are more often associated with neurologic impairment. They also may occur without visible injuries in X-rays. The problems of conventional radiologic diagnostics include before all the differential diagnosis between synchondrosis, apophysis and fracture lines. MRI is indicated in case of neurologic deficits without radiologic abnormalities. In principle the fracture types correspond to those seen in adults. In addition growth specific injuries of the end-plates (growth plates) or ring apophysis may occur. Stable compression fractures are treated conservatively. The spontaneous remodelling capacity for posttraumatic deformities decreases with age: in children below the age of ten years the remodelling capacity for posttraumatic kyphosis is excellent whereas deformities in the frontal plane show no or only incomplete remodelling. Unstable fractures and injuries with associated compression of neural structures should be treated conservatively.

Accidental Falls↗
PubMed2002

Esophageal perforation after fracture of the cervical spine: case report and review of the literature.

We present a posttraumatic esophageal tear that occurred in a 55-year old patient after a truck accident. He sustained a two-level injury with a type II odontoid fracture and a unilateral fracture of the left superior articular process of C6 with an incomplete quadriplegia at C5. Both lesions were treated nonoperatively. The tear was attributed to the stretching of the esophagus over anterior degenerative spurs at the level of the lesion (C5-C6) during hyperextension. The diagnosis of the esophageal perforation was delayed for 6 days. The treatment consisted of surgical debridement, volume expansion, antibiotic therapy, hyperbaric oxygenation, assisted ventilation, and esophageal exclusion. A complete review of the literature was performed.

Cervical Vertebrae↗
PubMed1999

[Atlas fractures].

Fractures of the atlas account for 1-2% of all vertebral fractures. We divide atlas fractures into 5 groups: isolated fractures of the anterior arch of the atlas, isolated fractures of the posterior arch, combined fractures of the anterior and posterior arch (so-called Jefferson fractures), isolated fractures of the lateral mass and fractures of the transverse process. Isolated fractures of the anterior or posterior arch are benign and are treated conservatively with a soft collar until the neck pain has disappeared. Jefferson fractures are divided into stable and unstable fracture depending on the integrity of the transverse ligament. Stable Jefferson fractures are treated conservatively with good outcome while unstable Jefferson fractures are probably best treated operatively with a posterior atlanto-axial or occipito-axial stabilization and fusion. The authors preferred treatment modality is the immediate open reduction of the dislocated lateral masses combined with a stabilization in the reduced position using a transarticular screw fixation C1/C2 according to Magerl. This has the advantage of saving the atlanto-occipital joints and offering an immediate stability which makes immobilization in an halo or Minerva cast superfluous. In late instabilities C1/2 with incongruency of the lateral masses occurring after primary conservative treatment, an occipito-cervical fusion is indicated. Isolated fractures of the lateral masses are very rare and may, if the lateral mass is totally destroyed, be a reason for an occipito-cervical fusion. Fractures of the transverse processes may be the cause for a thrombosis of the vertebral artery. No treatment is necessary for the fracture itself.

Bone Nails↗
PubMed1998

Safety and accuracy of transarticular screw fixation C1-C2 using an aiming device. An anatomic study.

STUDY DESIGN: In this anatomic study, the safety and accuracy of C1-C2 transarticular screw placement was tested in a normal anatomic situation in cadaver specimens using a specially designed aiming device. OBJECTIVES: To assess the safety and accuracy of transarticular screw placement using the technique described by Magerl and a specially designed aiming device. SUMMARY OF BACKGROUND DATA: Transarticular C1-C2 screw fixation has been shown to be biomechanically superior to posterior C1-C2 wiring techniques. Several clinical series have been reported in the literature. However, no previous study assessing the accuracy or safety of this technique has been published. Structures at risk are the vertebral arteries, spinal canal, and the occiput-C1 joint. METHODS: Five frozen human cadaveric specimens were thawed and instrumented with 10 C1-C2 transarticular screws, according to the technique described by Magerl but using a specially designed aiming device described by the senior author (Jeanneret). After screw placement, the accuracy of screw positioning and the distance of the screws from the spinal canal, vertebral arteries, and atlanto-occipital joint were determined by anatomic dissection and radiographic analysis. RESULTS: The structure at greatest risk was the atlanto-occipital joint, with one screw found to be damaging the joint. Vertebral artery or spinal canal penetration was not observed in any of the specimens. Screw length averaged 45 mm and, with proper length, the screw tip was found to be located approximately 7.5 mm behind the anterior tubercle of C1 on lateral radiographs. CONCLUSIONS: This anatomic study demonstrates that C1-C2 transarticular screw fixation can be performed safely in a normal anatomic situation by surgeons who are familiar with the pertinent anatomy. The aiming device allowed safe instrumentation in all patients. In case of an irregular anatomic situation (e.g., congenital abnormalities or trauma), computed tomographic scan with sagittal reconstruction is recommended-in particular, to obtain information about the course of the vertebral artery.

Axis, Cervical Vertebra↗
PubMed1998

[Chronic back pain].

Low-back pain is a very common disease in Switzerland as elsewhere, with a prevalence of 65%. The pain is usually due to degeneration of the motion segment, but subsides spontaneously in some 95% of cases irrespective of the treatment. Only 5% of patients still have pain after one year; but account for over 80% of the costs due to low-back pain. Some patients can be helped by surgical fusion; however; preoperative identification of the pain source is mandatory. Since there is no consistent correlation between pain and the degree of degeneration of motion segments as seen on plain radiographs, functional radiographs, CT scan or MRI, other diagnostic methods such as facet blocks, discography and external diagnostic fixation must be used. After careful patient selection a fusion operation may be considered. Good results after fusion operations are reported in 60-80% of patients. The operative techniques are described.

Cost-Benefit Analysis↗
PubMed1996

The value of percutaneous transpedicular vertebral bone biopsies for histologic examination. Results of an experimental histopathologic study comparing two biopsy needles.

STUDY DESIGN: A 3.5-mm trephine was designed to overcome difficulties encountered in the histologic evaluation of vertebral bone samples obtained with a 2-mm trephine. OBJECTIVES: To compare the 3.5-mm trephine with the 2-mm trephine. SUMMARY OF BACKGROUND DATA: A review of results obtained with a 2-mm trephine showed that histologic examination of vertebral bone cores was disturbed by artifacts in 32 of 70 cases (46%). Although tissue diagnosis was possible from 61 samples, only 36 (51%) bone cores yielded a secure diagnosis. METHODS: Transpedicular bone cores were obtained from the bodies of 54 fresh cadaver vertebrae with both trephines. In each vertebra, the 2-mm trephine was used on one side, and the 3.5-mm trephine was used on the other side. Longitudinal sections were prepared and examined macroscopically for length and breakages and microscopically for trabeculae, marrow, and artifacts. Each sample was graded for its value for histologic examination. RESULTS: Significant differences were found between the two trephines for all criteria evaluated. Of 54 samples taken with the 2-mm trephine, 13 (24%) were graded "good," compared with 45 (83%) from the 3.5-mm trephine. Twelve (22%) "bad" samples were taken from the 2-mm trephine compared with three (6%) "bad" samples taken from the 3.5-mm trephine. CONCLUSIONS: The 2-mm trephine does not provide suitable bone cores for histologic examination, whereas samples obtained with the 3.5-mm trephine are suitable.

Aged↗
PubMed1996

Posterior rod system of the cervical spine: a new implant allowing optimal screw insertion.

A new implant system for posterior stabilisation of the occipitocervical junction and the cervical and upper thoracic spine is described. The system consists of rods and clamps. For fixation to the occiput, the 3.5-mm titanium rod goes over into a 3.5-mm AO-reconstruction plate. Several clamps may be fixed to the rod at variable intervals, depending on the anatomical situation and the specific needs. Five types of clamps with different angulations of the screw hole with respect to the rod allow optimal screw insertion and fixation of the rod at all levels instrumented. Locking screws may be used to allow fixed stabilisation of the screw to the rod. Hooks for sublaminar anchoring, connectors to other rods and a cross-linking device are also available. Unlike plate fixators, the system allows screw insertion at any angle and at any interval. Therefore, optimal screw insertion is possible in any anatomical situation. Furthermore, ample space is available for bone grafting of the posterior aspect of the lateral masses. This is especially important following a laminectomy. Preliminary clinical results in 20 patients are presented; no complications have been seen to date. Our system has recently been approved as an AO-implant.

Adult↗
PubMed1996

Posterior stabilization in L5-S1 isthmic spondylolisthesis with paralaminar screw fixation: anatomical and clinical results.

Combined anterior and posterior fusion with posterior instrumentation may be indicated in the treatment of select cases of L5-S1 spondylolisthesis. The instrumentation, however, is expensive and usually bulky, occasionally requiring removal. In an effort to avoid these problems, an L5-S1 paralaminar screw technique was developed for posterior stabilization after an L5-S1 anterior interbody fusion. The technique involves the placement of cortical screws from the base of the articular process of S1 to the pedicle of L5. This study evaluates the anatomic applications and clinical results of this technique. The relationship between the screw and L5 nerve root was examined using five cadaveric specimens with olisthesis of 0, 25, 50, and 75%. This work demonstrates that the screws can only be inserted safely if an L5-S1 olisthesis of at least 25% is present. If < 25%, the screws will either impinge on or directly injure the L5 nerve root. In the clinical study, the outcomes of 20 patients who had an isthmic spondylolisthesis of 25-81% and were treated with partial reduction, L5-S1 anterior interbody fusion, and L5-S1 posterior paralaminar screw fixation were reviewed. Nineteen patients had adequate posterior stabilization to completely heal an L5-S1 anterior interbody fusion without loss of the correction. In one patient, a pseudarthrosis occurred secondary to poor surgical technique of both anterior and posterior fusions. This patient required an additional L4-S1 posterior fusion 9 months later and had a good clinical outcome. No other complications due to screw placement occurred. We conclude that this procedure can be used safely and reliably for the posterior stabilization of L5-S1 after stable anterior L5-S1 interbody fusion in residual slips of at least 25%. Prerequisites are proper patient compliance and low weight. Compared with other posterior instrumentation systems, this screw fixation is inexpensive and does not require implant removal. The disadvantages of the method are the degree of difficulty of the procedure and the limited clinical application to cases of L5-S1 spondylolisthesis with corrected residual slips of 25 to 50-60%. The procedure is technically demanding and should be limited to those surgeons who are comfortable with the method.

Adolescent↗
PubMed1994

Occipitocervical fusion with posterior plate and screw instrumentation. A long-term follow-up study.

STUDY DESIGN: Thirty-two patients at one institution underwent occipitocervical fusions with posterior plate and screw instrumentation. The average follow-up was greater than 4 years (50 months). METHODS: AO plates and screws were used and in more than 50% of the cases, the Magerl transarticular C1-C2 screw technique enhanced the occipitocervical instrumentation. In nine patients, cement was used and thus are excluded in evaluation of fusion results. All 23 patients attained solid fusions. No pseudarthrosis occurred. The average time to fusion was 13 weeks. Halos or traction immobilization was not used postoperatively. The average time of the simple orthosis wear was 11 weeks. Patients were out of bed on an average of the second postoperative day with a range of 1-4 days postoperatively. Reduction of the atlantoaxial joint was required in 10 of the 23 patients. At follow-up, nine remain reduced. RESULTS: In one patient, the atlantodens interval approximated the preoperative distance and radiographs demonstrated one transarticular C1-C2 screw was not placed satisfactorily. The average operative time was 172 minutes, and the average blood loss was 956 cc. The neurologic status of the patients improved or remained the same. No patient deteriorated neurologically. A total of 78 occipital screws were placed. No complications resulted from any of these screws. One intraoperative complication occurred secondary to massive bleeding after a transarticular screw hole was drilled. Bone wax was placed over the drill hole and the bleeding ceased. No postoperative problems occurred in this patient. Most specifically, no central nervous system sequela was evident. CONCLUSIONS: The conclusions from this study are that posterior occipitocervical fusion can be performed very safely with plate and screw instrumentation. An extremely high fusion rate can be expected with minimal complications and minimal postoperative immobilization. This technique, however, is technically demanding.

Adolescent↗
PubMed1994

The problem of stabilization after sacrectomy.

After sacrectomy, mobilization of the patient is only possible if a stable connection between the spine and pelvis can be obtained. We have developed an instrumentation to fix the pelvis to the spine. Two DHS screws connected to each other were implanted in the pelvis (one DHS screw into each ilium). An internal spine fixator, anchored in L3 and L4 through transpedicular Schanz screws, was attached to these DHS screws. Two patients were stabilized with this implant after sacrectomy. One patient was able to walk with crutches; the other patient was able to walk even without crutches.

Adult↗
PubMed1994

Treatment of osteomyelitis of the spine using percutaneous suction/irrigation and percutaneous external spinal fixation.

External skeletal fixation is a well-known tool in the management of infection of long bones. However, the application of external skeletal fixation in the treatment of spinal infection has not been previously reported. We have used percutaneous external spinal fixation (PESF) for the treatment of osteomyelitis of the spine in 23 patients since 1981. The treatment consists of percutaneous vertebral biopsy for bacteriologic diagnosis, installation of a suction/irrigation system into the intervertebral disk space, and posterior stabilization (and reduction if indicated) with an external fixator placed percutaneously. This treatment was conceived in 15 patients as definitive treatment. One patient died due to pulmonary embolism. In 12 patients, the infection healed without further operative treatment. Preoperative kyphosis averaged 15 degrees (range 0-30 degrees). At follow-up, kyphotic deformity also averaged 15 degrees (range 0-30 degrees). Two patients required anterior debridement and bone grafting because of progression of bony destruction. In eight patients, PESF was performed emergently, followed by planned anterior debridement and interbody grafting. The treatment was successful in all patients. All fusions healed. Preoperative kyphosis averaged 18 degrees (range 0-40 degrees). At follow-up, kyphotic deformity averaged 10 degrees (range 0-22 degrees). Our present indications are listed below and comprise pyogenic and tuberculous osteomyelitis of the spine localized between T3 and S1. The procedure is an alternative to conservative or more invasive operative treatment modalities in the following conditions: (a) painful lesions of the spine with minimal bone loss, not amenable to efficient orthotic stabilization (thoracic spine from T3 to T9, lumbosacral junction, elderly patients, or presence of deleterious general conditions); (b) osteomyelitis of the spine from T3 to S1, when emergency decompression of the spine is mandatory because of neurologic deterioration due to the kyphotic deformity or to a noncapsulated epidural abscess and anterior decompression is not possible emergently; (c) pyogenic osteomyelitis of the spine at L5/S1, when operative treatment is indicated. In addition, percutaneous insertion of external skeletal fixation is indicated in the presence of infected wounds, making internal posterior stabilization unsuitable (e.g., after open decompression of epidural abscess, postoperative infections).

Adult↗
PubMed1994

Transpedicular screw fixation of articular mass fracture-separation: results of an anatomical study and operative technique.

Articular mass fracture-separation accounts for 9% of the fractures of the lower cervical spine. Neurologic complications are frequent and are usually radicular in nature. Unreduced, these fractures may cause persistent neck pain. The treatment is usually surgical, fusing two or three vertebrae. In this article we present a new treatment modality using reduction and stabilization of the dislocated fragment with a transpedicular lag screw. Previous anatomic studies have shown that the pedicles of the lower cervical spine are wide enough to accept 4.0-mm screws. An anatomic study was performed showing that transpedicular screw fixation is safe when the following technique is used: entry point 3 mm beneath the facet joint on a vertical line in the middle of the articular mass. The drill is angled medially, depending on the preoperative measurement on the computed tomography scan (average 45 degrees). The drill aims toward the cranial third of the vertebral body as seen on lateral fluoroscopy. The tap-drilling method is used. After placement of 33 screws in cadaver pedicles of the cervical spine, 10 had minor breakout of the cortex of the pedicle (only small parts of the threads were penetrating the cortex); none showed major violation of the pedicle wall. The most common direction of minor pedicle violation was lateral. Transpedicular screw fixation has been successfully used in three patients.

Accidents, Traffic↗
PubMed1994

Percutaneous diagnostic stabilization for low back pain. Correlation with results after fusion operations.

Diagnostic external fixation was performed in 101 patients with disabling low back pain. In 47 patients, pain was relieved by stabilization but returned after destabilization. These patients were considered good candidates for a fusion operation. Results after fusion are available for 34 patients: 14 (41%) patients had a good, 12 (35%) had a fair, and 8 (14%) had a bad result. In two patients, pain was relieved by stabilization and did not return after fixator removal; no fusion operation was performed. Fifty-two patients did not respond positively to external fixation. Nine were operated on despite negative results with fixation. Of these, seven patients had a bad result, one a good result (however, this patient had spinal stenosis and the indication for external fixation was wrong), and, in one, the follow-up time is too short. Positive results with external skeletal fixation may predict a successful fusion operation with reasonable accuracy. If stabilization does not relieve the patient's pain, spinal fusion is unlikely to be of any benefit.

Adult↗
PubMed1993

Burst-shear flexion-distraction injuries of the lumbar spine.

Seven cases of a previously undescribed lesion of the lumbar spine consisting of a burst fracture of the vertebral body associated with a posterior subluxation of the adjacent lower level facet joints are described. The lesion is due to a flexion-distraction mechanism. All seven cases reported involve a burst fracture (four upper burst, one burst-split, and two complete burst fractures). The dislocation line goes through the upper end-plate, through the posterior wall of the fractured vertebra, through the spinal canal, and through the caudal facet joints. The caudal disk is not destroyed primarily, but is involved in cases of burst-split or complete burst fractures. The treatment is surgical: reduction of the posterior subluxation, reduction of the burst fracture with anterior distraction (e.g., AO internal fixator or any other pedicle system allowing anterior distraction and reduction of the burst fracture), transpedicular bone grafting of the burst fracture if necessary, and fusion of the destroyed motion segment(s).

Accidental Falls↗