Trans iliac-sacral-iliac bar stabilisation to treat bilateral lesions of the sacro-iliac joint or sacrum: anatomical considerations and clinical experience

The use of trans iliac-sacral-iliac bars is an alternative to sacro-iliac s crews in the treatment of bilateral lesions of the posterior pelvic ring, a nd the same biomechanical principles can be applied. Of 20 patients, ten men and ten women, a CT-scan of the pelvis was performe d to study the individual and common safe area at the level of S1 and S2. T he location and maximal diameter of the individual safe area were studied u sing a computer-navigation system, displaying images in sagittal, coronal a nd axial anatomic planes together with a 3-D reconstruction. The common saf e area was studied using three points: upper- (UA) and lower anterior corne r (DA) of S1 and S2, and the centre of the safe area. It would have been possible to place an iliac-sacral-iliac bar (5 mm or mor e) in S1 and S2 in all the men, but in the women a bar could only have been inserted in only five in S1 and eight in S2. A statistically significant d ifference between men and women was found at S1 (P = 0.033) but not at S2 ( P = 0.211). No significant correlation was found between the diameter of th e safe area at both levels in men and women and age, height, and weight. Fu rthermore, no common safe area of 5 min or more was measured at the same le vels. Four patients were treated using trans iliac-sacral-iliac bars. Three were placed under fluoroscopic control in combination with a frame, and in one p atient an image-guided system was used. A postoperative CT confirmed the co rrect position of the bars in each patient. The complexity and individual variability of the sacrum makes complex preop erative planning of the iliac-sacral-iliac path mandatory. (C) 2001 Elsevie r Science Ltd. All rights reserved.