Anterior column realignment (ACR) for focal kyphotic spinal deformity using an anterior to psoas approach and anterior longitudinal ligament release.

ABSTRACT

Background: The anterior-to-psoas (ATP) approach to the lumbar spine has been proposed as an alternative to the transpsoas approach for approaching the disc space without dissecting through the psoas muscle, thus decreasing the risk of injury to the lumbar plexus. There are no prior studies that evaluates the clinical application of anterior longitudinal ligament (ALL) release and anterior column realignment (ACR) using the ATP approach. The objective of this study was to describe and evaluate the safety of ACR using an ATP approach with release of both the ALL and bilateral annulus for correction of a focal kyphotic lumbar deformity. Methods: A retrospective analysis of fourteen consecutive patients at a single institution between January 2017 and December 2019 of patients undergoing ACR using an ATP approach for lumbar flatback syndrome with focal kyphotic lumbar deformity by a single surgeon was performed. Primary outcome measures were pre- and postoperative radiographic parameters. Secondary outcome measures were perioperative adverse events (AEs), 30-day readmissions/reoperations, discharge disposition, post-operative length of stay (LOS), and radiographic complications. Results: Fourteen consecutive patients (mean age 67.0±3.9 years, 8 males, 6 females) with 15 total ACR levels were included in the study. A grade 1 posterior column osteotomy (PCO) with posterior instrumentation was performed at all ACR levels. L2-L3 ACR was performed in nine patients, L3-L4 in four patients, and L4-L5 in two patients. Mean preoperative disk lordotic angle at the ACR level was 5.4°±5.9° of kyphosis. Mean increase in postoperative disk lordotic angle was 24.0°±8.5° at a mean follow-up of 34.0±23.4 months. Conclusions: ACR can be performed with a complete ALL release under direct visualization using the ATP approach. This technique can be a safe and effective method for achieving substantial correction of a focal kyphotic deformity within the lumbar spine.