The Minimally Invasive Interbody Selection Algorithm (MIISA) for Spinal Deformity

Abstract

Abstract INTRODUCTION Multiple MIS interbody fusion options have been utilized as MIS deformity surgery has become more prevalent. However, at this time there is little guidance for approach selection for MIS deformity surgery. The minimally invasive interbody selection algorithm (MIISA) was created to provide a framework for rational decision making for surgeons who are considering MIS deformity surgery. METHODS A team of experienced spinal deformity surgeons developed the MIISA, incorporating the experience of a retrospective dataset from 223 MIS surgeries collected over a 5-yr period. The algorithm leads to one of 4 interbody approach options (including ALIF, ACR, LLIF, and TLIF) that allow either indirect or direct decompression of the neural elements, possibly restore disc space and foraminal height, and may restore lordosis. The algorithm was developed by fellowship-trained spine surgeons experienced with spinal deformity surgery and validated with the retrospective MIS database. RESULTS A total of 11 surgeons completed 223 MIS deformity surgeries with 661 interbody devices. These cases were reviewed and the type of interbody approach used at each level from L1-S1 was recorded. The MIISA was created with substantial agreement. Surgeons preferred lateral approaches for L1-L2, L2-L3, and L3-L4. They preferred lateral approaches at L4-L5, but this was muted by more use of TLIF and ALIF at that level. They preferred TLIF to ALIF at L5-S1. The increase in segmental lordosis at L2-L3 was significantly greater with LLIF than TLIF. The increase in segmental lordosis at L4-L5 was significantly greater with ALIF than LLIF or TLIF. The increase in segmental lordosis at L5-S1 was greater with ALIF than TLIF. CONCLUSION The use of the MIISA provides consistent and straightforward guidance for surgeons who are considering an MIS approach for the treatment of patients with adult spinal deformity. The application of this algorithm could provide a platform for surgeons to achieve the desired goals of surgery.