Abstract
Purpose: This study analysed nerve trunk injury associated with posterior fractures of the pelvic girdle, distinguishing initial post-trauma damage from morbidity correlated to treatment by reduction and iliosacral screw fixation.
Material: Fifty bone or ligament injuries to the posterior pelvic girdle were identified in 44 patients. Management included initial external reduction and differed fixation using iliosacral screws inserted under fluorescence guidance.
Methods: The metameric examination of the lumbar and sacral trunks (L2, L3, L4, L5, S1, S2, S3) was performed at admission when the patient was conscious. The postoperative work-up included a complete neurological exam and computed tomography assessment of the screw trajectory. The quality of the reduction was quantified on the anterioposterior view of the pelvis. At last follow-up, evolution of symptoms ± EMG, Trendenburg gait, Mageed score, QMS score and pain (assessed on a visual analogue scale) were recorded.
Results: Preoperatively, 14 deficits of the nerve trunks were identified. The neurological status was unknown for eleven bone and ligament injuries because the patients were sedated at admission. Postoperatively, 28 deficits were identified. Fourteen (50%) involved the lumbosacral trunks L4 and L5, five the S1 root, six L4, L5, S1 territories, and three L5 to S4.
Computed tomography demonstrated 15 extraosseous screws lying anteriorly to the sacral ala or in the sacral canal. These extraosseous screws were associated with neurological deficits in nine cases without a preoperative diagnosis. In six cases, the extra-ossesous screw was not associated with any postoperative deficit. In five cases, neurological lesions diagnosed after the operation were not associated with an extra-osseous screw. Twenty-six neurological lesions were reviewed at a mean follow-up of 25 months: improvement was observed in 19, no change in five and aggravation in two.
Conclusion: Initial diagnosis of neurological injury with precision of the localisation can be established for only half of pelvic girdle fractures. The main mechanism involves stretching of the lumbosacral trunk by displacement of the sacral ala. Injury to the superior gluteal nerve is often associated. Closed reduction or compression of a nerve trapped in the fracture gap during screw fixation could be a second mechanism. Finally, rigorous screw insertion is necessary to avoid extra-osseous trajectories lying anteriorly to the sacral ala.
The abstracts were prepared by Docteur Jean Barthas. Correspondence should be addressed to him at Secrétariat de la Société S.O.F.C.O.T., 56 rue Boissonade, 75014 Paris.
