Segmental Interbody, Muscle-Preserving, Ligamentotaxis-Enabled Reduction: "SIMPLER" Technique for cMIS Correction of ASD.

Background: Correction of adult spinal deformity (ASD) through minimally invasive techniques is a challenging endeavor and has typically been reserved for experienced surgeons. This publication aims to be the first high-resolution technique guide to demonstrate a reproducible technique for ASD correction utilizing circumferential minimally invasive surgery (cMIS) without an osteotomy. The Segmental Interbody, Muscle-Preserving, Ligamentotaxis-Enabled Reduction (SIMPLER) technique is a novel ligamentotaxis-based scoliosis surgery that represents a paradigm shift from traditional osteotomies toward patient-specific correction.

Methods: The senior author's (N.A.) cMIS technique for ASD correction without an osteotomy is described using high-resolution photographs, computer-generated imagery (CGI), and a case example. Step-by-step intraoperative photographs document a novel muscle-preserving posterior spinal exposure, spinal robotic safety protocol for instrumentation, dedicated deformity instrumentation system, rod reduction sequence, and minimally invasive fusion technique. CGI assists to reinforce technical considerations described by intraoperative photographs.

Results: The SIMPLER technique is documented from incision to closure with high-resolution pictures including CGI to highlight concepts documented in photographs. Technical considerations were detailed for all aspects involved in the planning and execution of an osteotomy-free deformity correction.

Conclusion: This represents the first in-depth technical description of ligamentotaxis-based, osteotomy-free, ASD scoliosis correction. The SIMPLER approach is reproducible and minimally invasive and can be done routinely for appropriately selected deformity candidates. This technique serves as a foundation to externally validate previously described cMIS ASD deformity correction outcomes.

Clinical relevance: Circumferential minimally invasive spinal deformity correction is reproducible and can be achieved reliably through the use of the SIMPLER technique, without the use of an osteotomy.

Level of evidence: 5: