The MIS PSO is a hybrid approach using less-invasive surgical approaches combined with traditional open spinal deformity techniques for the treatment of adult spinal deformities. The MIS PSO allows for the correction of spinal deformities in the coronal and sagittal planes, even in the fixed spine, and simultaneously mitigating the morbidity of traditional open surgery by preserving the soft tissues and minimizing blood loss. This article discusses the surgical steps of the MIS PSO and reviews our experience.