Minimally invasive lateral lumbar interbody fusion for adult spinal deformity

Study Design. A retrospective cohort study. Objective. To evaluate the clinical and radiological efficacies of supplementing minimally invasive lateral lumbar interbody fusion (LLIF) with open posterior spinal fusion (PSF) in adult spinal deformity (ASD). Summary of Background Data. Minimally invasive techniques have been increasingly applied for surgery of ASD. Few reports have been published that directly compare LLIF combined with PSF to conventional PSF for ASD. Methods. To evaluate the advantages of minimally invasive LLIF for ASD, patients who underwent minimally invasive LLIF followed by open PSF (combined group) were compared with patients who only underwent PSF (only PSF group). The clinical and radiological outcomes for deformity correction and indirect decompression were assessed. The occurrence of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) were also evaluated. Results. No significant differences were observed in the clinical outcomes of the Oswestry Disability Index (ODI), visual analog scale, and major complications including reoperations between the groups. No additional advantage was found for coronal deformity correction, but the restoration of lumbar lordosis in the combined group was significantly higher postoperatively (15.3° vs. 8.87°, P=0.003) and last follow-up (6.69° vs. 1.02°, P=0.029) compared to that of the only PSF group. In the subgroup analysis for indirect decompression for the combined group, a significant increase of canal area (104 vs. 122mm 2) and foraminal height (16.2 vs. 18.5mm) was noted. The occurrence of PJK or PJF was significantly higher in the combined group than in the only PSF group (P=.039). Conclusion. LLIF has advantages of indirect decompression and greater improvements of sagittal correction compared to only posterior surgery. LLIF should be conducted considering the above-mentioned benefits and complications including PJK or PJF in ASD. Level of Evidence: 4 .