Outcomes and complications of extension of previous long fusion to the sacro-pelvis: Is an anterior approach necessary?

Background: Patients with previous multilevel spinal fusion may require extension of the fusion to the sacro-pelvis. Our objective was to evaluate the outcomes and complications of these patients, stratified based on whether the revision was performed using a posterior-only spinal fusion (PSF) or combined anterior-posterior spinal fusion (APSF). Methods: A retrospective, multicenter evaluation of adults (>18 years old) with a history of prior spinal fusion for scoliosis (≥4 levels) terminating in the distal lumbar spine requiring extension of fusion to the sacro-pelvis (including iliac fixation in all cases), with minimum 2-year follow-up, was performed. Patients were stratified based on approach (APSF vs. PSF) and inclusion of pedicle subtraction osteotomy (PSO). The PSF group included patients treated with an anterior interbody fusion done through a posterior approach, whereas patients in the APSF group all had both anterior and posterior surgical approaches. Clinical outcomes were based on the Scoliosis Research Society (SRS-22) questionnaire. Results: Between 1995 and 2006, 45 patients (mean age = 49 years) met inclusion criteria, with a mean follow-up of 41.9 months (range 24 to 135 months). Demographic, preoperative, operative, and postoperative radiographic, SRS-22, and follow-up results were similar between APSF (n = 30) and PSF (n = 15) groups. The APSF group had more complications (13 of 30 vs. 3 of 15) and a greater number of pseudarthrosis (4 of 30 vs. 0 of 15) than the PSF group; however, these differences did not reach statistical significance. Patients treated with a PSO (n = 13) had greater sagittal vertical axis correction (7.7 cm vs. 2.2 cm; P =.04) compared with patients not treated with a PSO (n = 32). There were no differences in complication rates or follow-up SRS-22 scores based on whether a PSO was performed (P >.05). Conclusions: Among adults with previously treated scoliosis requiring extension to the sacro-pelvis, PSF produced radiographic fusion and clinical outcomes equivalent to APSF, whereas complication rates may be lower. PSO resulted in greater sagittal plane correction, without an increase in overall complication rates.