Professor of Orthopedic Surgery Cedars Sinai Medical Center Cedars Sinai Medical Center Los Angeles, CA, US
Disclosure(s):
Neel Anand: No relevant disclosure to display
Introduction: Deformity correction with cMIS involving longer segments spanning the thoracolumbar spine is technically more challenging than fusions limited to lumbar spine. Rod fixation and reduction of deformity over more vertebral levels in a minimally invasive subfascial manner contributes to the technical difficulty. Radiological and clinical outcomes specific to fusions involving these long segments for ASD have not been delineated previously.
Methods: A prospectively collected database of all patients who underwent CMIS correction of ASD from Jan2011 to December2021 was studied. Inclusion criteria: 6+ levels, (UIV): T12 and above, LIV: S1 and below in patients with ASD (Cobb>20, SVA>50mm, PI-LL>10, PT>20), min 2year follow-up. Pre-operative, post-operative, and ≥2years radiographic parameters, clinical outcomes, complications and readmissions were analyzed.
Results: A total of 105patients were identified, of which 4patients had passed away from natural causes and 7were lost to follow-up. 30patients had a follow up between 1-2years and 64patients had ≥2year data and were included for this study (Mean:59month(24-130). The clinical outcomes scores VAS , TIS, ODI, SRS22 were all significantly improved postoperatively. The sagittal radiological measure of alignment including SVA, PI-LL, LL and TK improved significantly compared to preop, whereas correction in coronal alignment/CVA was not statistically significant. 3patients had PJF and underwent hardware revision. Pseudoarthrosis with hardware failure was noted in 3patients at thoracolumbar junctions and underwent reinstrumentation. 2patients had hardware prominence with associated localized pain posteriorly and underwent hardware removal. 4patients had asymptomatic hardware failure noted past 13months that did not need any intervention. 2patients had superficial wound dehiscence and underwent debridement and closure.
Conclusion :: In the treatment of ASD, cMIS involving long segment fusions is a safe and effective option both for deformity correction and improving patient outcomes significantly. There were no catastrophic complications. The complication profile and the rates of hardware failure and proximal junctional failure are noted to be lower compared to reported outcomes with open deformity correction techniques.
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