Purpose of the study: We present a review of the two-year outcome of a new clinical sacroiliac fixation technique used in our first seven patients.

Material and methods: Between May 2002 and March 2003, seven patients with a Tile C fracture of the pelvic girdle were stabilized with a new operative technique. This technique used two sacral screws linked to two iliac expansive screws via a 5.5 mm rod. Three of the patients presented preoperative neurological injuries attributed to the trauma (L5 or S1 paralysis). All presented associated lesions: lower limb (n=3 patients), spine (n=2), acetabulum (n=2). Mean patient age was 36.3 years. We present a retrospective clinical and radiological review of these seven cases. The Majeed score, the radiological index of lower limb length, and the combined index of vertical displacement and sacroiliac CT results were noted.

Results: The mean Majeed score was 93. Reduction of the combined vertical displacement was considered excellent or good (< 10 mm) in all patients; The reduction in the leg length discrepancy was considered good for all patients. There was no loss of reduction at last follow-up. There were no septic or skin complications and no complications related to implanted material. The implants were removed in one patient. The sacroiliac CT revealed formation of ossification bridges in all patients.

Discussion: The results of our small series are encouraging, particularly for vertical stability over time. There was no case of lysis around the screws and the clinical results were satisfactory.

Conclusion: For us, this technique is the optimal method for the treatment of Tile C injury to the pelvic girdle. This technique enables vertical stabilization while maintaining a certain degree of horizontal mobility facilitating reduction and fixation of the associated anterior injuries. This technique has its limitations since it is not particularly adapted for posterior lesions with fracture of the sacrum in Denis zone 2. These early encouraging results will require further long-term assessment in a larger group of patients.

Purpose: Pelvic girdle fractures with vertical and horizontal instability (Tile classification class C) are classical indications for surgical stabilisation of the posterior and anterior lesions. There is general agreement concerning the anterior fixation, but several methods have been described for the posterior fixation: open or percutaneous sacroiliac screwing using fluoroscopic or computed tomographic guidance, sacral compression bar applied laterally on the posterior iliac masses, sacral screw for sacroiliac fixation using the Galveston technique, among others.

Material and methods: We propose a new sacroiliac fixation technique for fractures of the pelvic girdle associating vertical and horizontal instability (Tile classification class C). This fixation technique controls vertical displacement while authorising, if needed, a certain degree of mobility in the horizontal plane allowing easier reduction of the anterior fracture. This technique uses two sacral screws, one in S1 and the other in S2, and two iliac screws. The iliac screws are inserted in the posterior iliac crest passing through two sacroiliac connectors placed on a rod connecting the two sacral screws. Vertical displacement is controlled by blocking the two connectors on the screw heads. If needed, the connectors can be left unblocked allowing a certain degree of freedom for moving the half-pelvis in the horizontal plane.

Results: This technique was used in four cases. Anatomic reduction was achieved. There was no secondary movement of the osteosynthesis material and no secondary displacement. Because of the quality of the fixation, the sitting position was allowed rapidly as was full-weight bearing and walking. This type of fixation is reserved for type C12 fractures of the Tile classification.

Purpose: Analysis of the sagittal balance of the spine is a fundamental step in understanding spinal disease and proposing appropriate treatment. The objectives of this prospective study were to establish the physiological values of pelvic and spinal parameters of sagittal spinal balance and to study their interrelations.

Material and methods: Two hundred fifty lateral views of the spine taken in the standing position and including the head, the spine and the pelvis were studied. The following variables were noted: lumbar lordosis, thoracic kyphosis, sagittal tilt at 9, sacral slope, pelvic incidence, pelvic version, intervertebral angle, and the vertebral wedge angle from T9 to S1. These measures were taken after digitalising the x-rays. Two types of analysis were performed. A descriptive univariate analysis was used to characterise angular parameters and a multivariate analysis (correlation, principal component analysis) was used to compare interrelations between the variables and determine how economic balance is achieved.

Results and discussion: Mean angular values were: maximal lumbar lordosis 61±12.7°, maximal thoracic kyphosis 41.4±9.2°, sacral slope 42±8.5°, pelvic version 13±6°, pelvic incidence 55±11.2°, sagittal tilt at T9 10.5±3.1°. There was a strong correlation between sacral slope and pelvic incidence (r=0.8), lumbar lordosis and sacral slope (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 sagittal tilt at T9, sacral slope, pelvic version, lumbar lordosis, and thoracic kyphosis (r=0.98). Multivariate analysis demonstrated three independent parameters influencing sagittal tilt at T9, reflecting the lateral balance of the spine. The first was a linear combination of the pelvic incidence, lumbar lordosis and sacral slope. The second was pelvic version and the third thoracic kyphosis.

Conclusion: This work provides an aid for analysis and comprehension of anteroposterior imbalance observed in spinal disease and also to calculate with the linear regression equations describing the corrections to be obtained with treatment.