[Lumbar-iliac fixation using the Cotrel-Dubousset instrumentation in pelvic fractures. Apropos of 3 cases].

Purpose Of The Study: The authors propose the use of Cotrel-Dubousset instrumentation in pelvic ring fractures with posterior trans-sacral disruption. They report 3 cases, describe the operative procedure and analyse the advantages and inconveniences of this method.

Material: 3 patients, injured after hand-gliding fall, presented at their admission, a fracture of the pelvis with associated lesions: the first one had a pelvic ring fracture type C2 (according to TILE classification), several associated fractures (femur, ankle, wrist), and brain trauma. After ten days of coma, he complained of severe bilateral sciatica and deficit of the cauda equina the second patient had a pelvic ring fracture type C1 (with 2.5 cm of ascension of the hemipelvis) associated fracture of T12 without neurologic lesion the third patient had a pelvic ring fracture type B2 with a fracture of T12 with palsy grade B (according to Frankel classification).

Methods: Pelvic ring fracture were treated in all cases, by a posterior approach, reduction and internal fixation using lombo-biiliac Cotrel-Dubousset (C.D.) instrumentation. The first case had bilateral stabilisation after sacral laminectomy and transverse iliac bone graft. Vertical displacement was corrected by distraction, lesing a pedicular screw in L5.

Results: Initial anatomic result was good in all cases without at long term, in 2 cases. The third patient presented infection after one week, due to muscular necrosis. Instrumentation was removed after only 4 months, 50 per cent of the initial reduction was lost because of a chronic infection around the screws in the tuberosity. Furtheriess all patients had good clinical issue, with bone union, no limb length discrepancy and good neurologic improvement.

Discussion: The use of C.D. instrumentation allowed correction of the elementary displacements, especially of vertical displacement, which is often difficult to reduce exactly when other procedures are used. It allows early mobilisation of the patients, with associated lesions or neurologic deficit. The implants have to be removed after bone union to restore lumbar spine mobility.

Conclusion: C.D. procedure can be used, in pelvic ring fractures with posterior transsacral disruption. This procedure seems to be especially efficient in case of vertical displacement (grade C according to Tile classification), because of the easiness of the reduction. According to our three operated cases, we cannot be sure of the permanence of the initial reduction because infection occurred in the most displaced case. Anyway advantages of the procedure seem to be more important than inconveniences (removal of the implants) in these uncommon lesions.