Spinal trauma with a complete anterior vertebral body dislocation: a report of three cases.

STUDY DESIGN: Retrospective review of three cases. OBJECTIVES: Severe trauma can be responsible for a complete spinal anterior dislocation with a 100% anterior slip of the vertebral body. Three cases of this uncommon lesion are reported. SETTING: France. METHODS: The data of three cases of complete spinal anterior dislocation with a 100% anterior slip of the vertebral body were retrospectively reviewed. RESULTS: In all the cases, the vertebral dislocation was responsible for a severe neurological deficit and all patients had severe associated lesions. The diagnosis was made on plain radiographs. In one case of a multilevel injury, an extensive instrumented spinal fusion was necessary. In spite of the severe injury, two neurological deficits improved thanks to pedicular fractures, which widen the canal. CONCLUSION: The therapeutic goal is to achieve emergent vertebral alignment, neurological decompression and solid spinal fusion. A posterior facilitates this. Reduction of vertebral dislocation can be difficult to achieve and it is therefore mandatory to perform complete arthrectomy of the injured levels before reduction. Especially in young patients, severe disc lesions secondary to the wide vertebral displacement make it necessary to perform circumferential fusion.

[Extension tear-drop fracture of the axis: a surgically treated case]. / Fracture "tear-drop" en extension de l'axis. A propos d'un cas traité chirurgicalement.

Tear-drop fracture of the axis is an exceptional spinal fracture which generally occurs after high-energy trauma with hyper-extension of the cervical spine. Purely anterior fracture can occur with no real impact on stability. Orthopedic treatment provides good results in this situation. If the fracture is posterior, it continues into the C2-C3 intervertebral disc and the common posterior vertebral ligament, leading to C2C3 instability and possible retrolisthesis of C2 over C3 and neurological involvement. We report a case of tear-drop fracture of C2 with C3 instability without neurological involvement. This patient underwent posterior fixation with C2C3 arthrodesis which provided good quality bone fusion without secondary displacement or clinical aggravation.

[Physiological value of pelvic and spinal parameters of sagital balance: analysis of 250 healthy volunteers]. / Valeur physiologique des paramètres pelviens et rachidiens de l'équilibre sagittal du rachis: analyse d'une série de 250 volontaires.

PURPOSE OF THE STUDY: Sagital balance of the spine is a fundamental element necessary for understanding spinal disease and instituting proper treatment. The aim of this prospective work was to establish the physiological values of pelvic and spinal parameters of sagital balance of the spine and to investigate their interactions. MATERIAL AND METHOD: Pelvic and spinal parameters were measured on the standing radiographs of 250 healthy volunteers. The following parameters were measured on lateral views including the head, the spine and the pelvis: lumbar lordosis, thoracic kyphosis, sagital tilt at T9, sacral inclination, pelvic incidence, pelvic version, intervertebral angulation, and the vertebral cuneiformization from T9 to S1. These measurements were taken after digitalization of the radiographs. Two types of analysis were performed: a descriptive univariate analysis to characterize the angular parameters and multivariate analysis (correlation, principal component analysis) to detail the relative variations of these parameters. RESULTS AND DISCUSSION: Mean values were: maximal lumbar lordosis 61 +/- 12.7 degrees, maximal thoracic kyphosis 41.4 +/- 9.2 degrees, sacral inclination 44.2 +/- 8.5 degrees, pelvic version 13 +/- 6 degrees, pelvic incidence 55 +/- 11.2 degrees, sagital tilt at T9 10.5 +/- 3.1 degrees. There was a strong correlation between sacral inclination and pelvic incidence (r=0.86), pelvic version and pelvic incidence (r=0.66), lumbar lordosis pelvic incidence pelvic version and thoracic kyphosis (r=0.9) and finally between pelvic incidence and the following parameters: sagital tilt at T9, sacral inclination, pelvic version, lumbar lordosis, and thoracic kyphosis (r=0.98). The relations between the different parameters studied demonstrated that saggital tilt at T9, which reflects spinal balance, is determined by three independent factors. The first is a linear combination of pelvic incidence, lumbar lordosis, and sacral inclination. The second is pelvic version. The third is thoracic kyposis. CONCLUSION: This work provided a useful tool for analyzing and understanding anteroposterior imbalance in patients with spinal disease and also a means of calculating corrections to be made with treatment, established from the linear regression equations which were elaborated.

[Validation of a tool to measure pelvic and spinal parameters of sagittal balance]. / Validation d'un outil de mesure des paramètres pelviens et rachidiens de l'équilibre sagittal du rachis.

PURPOSE OF THE STUDY: Parameters determining sagittal balance are essential for optimal analysis and treatment of many spinal disorders. The purpose of this work was to validate a software designed to measure the principal parameters involved in sagittal balance of the spine. MATERIAL AND METHODS: Six parameters (lumbar lordosis, thoracic kyphosis, sagittal tilt at T9, pelvic index, pelvic tilt, slope of the sacrum) were measured on lateral views of the spine from 100 healthy volunteers free of any spinal disease. Two measurement techniques were used: manual measurement and automatic computerized measurement with this software. We hypothesized that manual measures could be accepted as reference values because they are currently the most widely used and because the computerized measurements were obtained using digitalized images that may have modified interpretation. The software was therefore validated by comparing the angles measured manually with the computer output. Inter- and intraobserver coefficients of variation were calculated for the two measurement techniques. One operator performed both series of measurements (manual and computerized). Two other operators preformed two series of independent measures using one of the measurement techniques. Finally, two new operators performed a complete series of measurements using both measurement techniques. Comparisons were performed with the t test for paired variables with calculation of the coefficients of correlation. Intraclass coefficients of correlation were determined for inter- and intra-observer variability. RESULTS: There was an excellent correlation between the manual measurements and the computerized measurements with intra-class coefficients of correlation varying from 0.82 to 0.96. Inter- and intra-observer variabilities were comparable for the two measurement techniques used to determine thoracic kyphosis, lumbar lordosis, pelvic index, pelvic tilt, and slope of the sacrum. Inter- and intra-observer variability was lower when the sagittal tilt was measured with the software specially designed. CONCLUSION: This comparison between two techniques for measuring pelvic and spinal parameters of sagittal balance of the spine demonstrated a good correlation between manual and the computerized measurements obtained with the software to be evaluated. Computer-assisted measurements not only provided a saving in time but also minimized inter- and intra-observer variability for the estimation of certain parameters.

[Sacroiliac fixation: a new technique after pelvic trauma]. / Une nouvelle technique de fixation sacro-iliaque dans les ruptures traumatiques de l'anneau pelvien.

We propose a new technique for sacroiliac fixation for the treatment of pelvic fracture with vertical and horizontal instability (Tile class C). This fixation technique allows control of vertical displacement while allowing, if needed, a certain degree of movement in the horizontal plane to facilitate reduction of anterior lesions. The technique involves insertion of two sacral screws, one in S1 and one in S2, and two iliac screws. The iliac screws are inserted in the posterior iliac crest through two sacroiliac connectors placed on a rod linking the two sacral screws. Vertical displacement is controlled by blocking the screw heads on the connecting rod. If needed, a certain degree of horizontal mobility of the half pelvis can be allowed by loosening the connectors on the rods. This technique was used for 4 patients. Anatomic reduction was achieved and no secondary movement of the osteosynthesis material nor secondary displacement were observed. The quality of the fixation allowed rapid weight bearing in the standing position and early walking without crutches. This type of fixation can only be used for type C12 fractures in the Tile classification.