Re-Operation Rates in Minimally Invasive, Hybrid and Open Surgical Treatment for Adult Spinal Deformity with Minimum 2-Year Follow-up

Presented at SMISS Annual Forum 2014
By Paul Park MD
With Behrooz Akbarnia MD, Juan Uribe MD, FACS, Neel Anand MD, Richard Fessler MD, PhD, Michael Wang MD, Praveen Mummaneni MD, David Okonkwo MD, PhD, Adam Kanter MD, Frank LaMarca MD, Christopher Shaffrey MD, Bryan Bolinger DO, Gregory Mundis Jr. MD, Peter Passias MD,

Disclosures: Paul Park MD None Behrooz Akbarnia MD A; Depuy Synthes Spine. B; NuVasive, K2M, Ellipse, Kspine. D; Alphatec Spine, NuVasive, Ellipse, Kspine, Nocimed., Juan Uribe MD, FACS None, Neel Anand MD None, Richard Fessler MD, PhD None, Michael Wang MD None, Praveen Mummaneni MD B; Globus, David Okonkwo MD, PhD B; Nuvasive, Zimmer-Biomet. F; Nuvasive, Zimmer-Biomet, Adam Kanter MD None, Frank LaMarca MD A; NIH, NREF, Globus, DePuy Synthes Spine. B; Biomet, Lanx, Globus. F; Globus, Stryker., Christopher Shaffrey MD None, Bryan Bolinger DO None, Gregory Mundis Jr. MD A; ISSGF, Nuvasive. B; K2M, Medicrea, Misonix, Nuvasive. C; K2M, Nuvasive. F; Nuvasive., Peter Passias MD B; Medicrea.,

Introduction:
Re-operation Rates in Minimally Invasive, Hybrid and Open Surgical Treatment for Adult Spinal Deformity with Minimum 2-Year Follow-up.

Aims/Objectives:
Minimally invasive surgical (MIS) techniques are gaining popularity in the treatment of adult spinal deformity (ASD). The premise is that MIS techniques will lead to equivalent outcomes and a reduction in complications when compared with open techniques. Potential issues with MIS techniques are a limited capacity to correct lumbar lordosis, unknown long-term efficacy, and potential need for revision surgery. This study compares re-operation rates and reasons for reoperation following MIS, hybrid, and open surgery for ASD through multi-center database analysis.

Methods:
We retrospectively analyzed a multicenter ASD database comparing open and MIS correction techniques. Inclusion criteria were: age >18 years, minimum 20° coronal lumbar Cobb angle, minimum of 3 levels fused, and minimum 2 year follow-up. Patients were propensity matched for preoperative sagittal vertebral axis (SVA), pelvic incidence - lumbar lordosis (PI-LL), and number of levels fused. We included 114 patients from three propensity-matched subgroups of 38 patients: (1) MIS: lateral or transforaminal lumbar interbody fusion (LIF) and percutaneous pedicle instrumentation, (2) Hybrid: MIS LIF with open posterior segmental fixation (PSF), and (3) OPEN: open posterior fixation +/- osteotomies.

Results:
There were no significant differences between groups in pre-op SVA or PI-LL (p>0.05). The MIS group had significantly fewer levels fused (4.7) than the OPEN group (6.8) (p=0.002). The rate of revision surgery was not significantly different between groups (p=0.196): MIS=15.8% (6/38), Hybrid=31.6% (12/38), OPEN=31.6% (12/38). The most common reason for reoperation in the OPEN group was a postoperative neurological deficit (10.5%) followed by proximal junctional kyphosis (PJK) (7.9%). The most common reason in the Hybrid group was PJK (13.2%) followed by infection (7.9%). The most common reason for reoperation in the MIS group was pseudoarthrosis (7.9%).

Conclusions:
Reoperation rates were not statistically different among the MIS, Hybrid, and OPEN surgical groups on multivariate analysis; however, the incidence was twice as high in Hybrid and OPEN groups. The most common reasons for reoperation were proximal junctional kyphosis, neurologic deficit, and infection for the hybrid and OPEN groups; whereas, it was pseudoarthrosis in the MIS group. The differences in reoperation rates demonstrate the unique advantages (e.g., low rate of infection due to limited tissue exposure) and the unique challenges (e.g., pseudoarthrosis due to limited ability to bone graft in a limited space) inherent with use of MIS techniques for deformity correction.