Complications and 2 to 10 Year Results of Long Fusions to the Sacrum and Pelvis for Adult Deformity: Is Bilateral Iliac Fixation Necessary?

Summary: A retrospective review of 50 patients undergoing long fusion to the sacrum and pelvis for adult deformity. 33 patients had bilateral pelvic fixation and 17 had unilateral or sacral fixation alone. Significant complications occurred, and most distal implant problems including all pseudarthroses were in the bilateral pelvic fixation group, who had worse correction of sagittal balance compared to the nonbilateral group. Is bilateral fixation required when sagittal balance is restored?

Purpose: To assess the rate of, and factors causing complications in patients undergoing long fusion for adult scoliosis.

Methods: 50 patients with Idiopathic (n=38) and degenerative (n=12) scoliosis undergoing instrumentation from L2 and above to sacrum and pelvis with a minimum 2 year follow-up were reviewed. There were 47 females and 3 males with an average age of 53.5 years (range 27.5 to 75.4).

Results: 46 patients had circumferential fusion, 11 with staged procedures, only 2 with anterior instrumentation. Bone allograft was utilized in 36 of 42 who had a structural graft at L5-S1, with autogenous bone supplementation in 39. The average levels of posterior instrumentation and fusion was 13. The proximal instrumented level ranged from T2 (7 pts) to L2 (1 pt). Nine patients were fused to S1 alone and 41 to the pelvis, of which 15 had Galveston, 18 bilateral and 8 unilateral iliac screws. Surprisingly, patients without bilateral pelvic fixation (Group 1, n=17) had a significantly better improvement in pre-op sagittal balance (85.4 vs. 23.1mm. 33 (66%) patients had 70 general complications, with 8 (16%) having deep wound infections. The 8 patients over 65 years of age had 19 complications. There were 39 implant problems, and 58 unplanned procedures were required.

Conclusion: Long instrumentation in adult deformity carries a high complication rate. Greater implant complications including pseudarthrosis occur in patients with bilateral pelvic fixation and correlates with incomplete correction of sagittal profile. Is bilateral pelvic fixation needed when sagittal balance is restored?