Early results of sacro-iliac joint fixation following long fusion to the sacrum in adult spine deformity.

BACKGROUND: The sacro-iliac joint (SIJ) is the largest joint in the human body. When the lumbar spine is fused to the sacrum, motion across the SIJ is increased, leading to increased degeneration of the SIJ. Degeneration can become symptomatic in up to 75% of the cases when a long lumbar fusion ends with a sacral fixation. If medical treatments fail, patients can undergo surgical fixation of the SIJ.

QUESTIONS/PURPOSES: This study reports the results of short-term complications, length of stay, and clinical as well as radiographic outcomes of patients undergoing percutaneous SIJ fixation for SIJ pain following long fusions to the sacrum for adult scoliosis.

METHODS: A retrospective review of all the patients who underwent a percutaneous fixation of the SIJ after corrective scoliosis surgery was performed in a single specialized scoliosis center between the years 2011-2013. Ten SIJ fusions were performed in six patients who failed conservative care for SIJ arthritis. Average age was 50 (range 25-60 years). The patients were 15.3 years in average after the original surgical procedure (range 4-25 years). Average post-operative follow-up was 10.25 months (range 15-4 months). The medical charts of the patients were reviewed for hospital stay, complications, pre- and post-operative pain, quality of life, and satisfaction with surgery using the visual analogues score (VAS), Scoliosis Research Society (SRS)22 and Oswestry Disability Index (ODI) questionnaires. Images were reviewed for fixation of the SIJ, fusion, and deviation of the implants from the SIJ.

RESULTS: There were no complications in surgery or post-operatively. Discharge was on post-operative day 2 (range 1-4 days). Leg VAS score improved from 6.5 to 2.0 (P < 0.005; minimal clinically important difference (MCID) 1.6). Back VAS score decreased from 7.83 to 2.67 mm (P < 0.005; MCID 1.2). ODI scores dropped from 22.2 to 10.5 (P = 0.0005; MCID 12.4). SRS22 scores increased from 2.93 to 3.65 (P = 0.035; MCID 0.2) with the largest increases in the pain, function, and satisfaction domains of the questionnaires.

CONCLUSION: Fixation of the SIJ in patients that fail conservative care for SIJ arthritis after long fusions ending in the sacrum provides a reduction in back pain and improved quality of life in the short and medium range follow-up period.