Early outcomes of minimally invasive anterior longitudinal ligament release for correction of sagittal imbalance in patients with adult spinal deformity

Abstract

The object of this study was to evaluate a novel surgical technique in the treatment of adult degenerative scoliosis and present our early experience with the minimally invasive lateral approach for anterior longitudinal ligament release to provide lumbar lordosis and examine its impact on sagittal balance. Methods. All patients with adult spinal deformity (ASD) treated with the minimally invasive lateral retroperitoneal transpsoas interbody fusion (MIS LIF) for release of the anterior longitudinal ligament were examined. Patient demographics, clinical data, spinopelvic parameters, and outcome measures were recorded. Results. Seven patients underwent release of the anterior longitudinal ligament (ALR) to improve sagittal imbalance. All cases were split into anterior and posterior stages, with mean estimated blood loss of 125 cc and 530 cc, respectively. Average hospital stay was 8.3 days, and mean follow-up time was 9.1 months. Comparing pre- and postoperative 36'' standing X-rays, the authors discovered a mean increase in global lumbar lordosis of 24 degrees, increase in segmental lumbar lordosis of 17 degrees per level of ALL released, decrease in pelvic tilt of 7 degrees, and decrease in sagittal vertical axis of 4.9 cm. At the last followup, there was a mean improvement in VAS and ODI scores of 26.2% and 18.3%. Conclusions. In the authors' early experience, release of the anterior longitudinal ligament using the minimally invasive lateral retroperitoneal transpsoas approach may be a feasible alternative in correcting sagittal deformity.

Figure 1

Intraoperative anterior-posterior radiographs demonstrating the curved retractor anterior to the disc space during dissection of the sympathetic plexus off the great vessels (a), and the intradiscal spreader in the disc space used to break the contralateral ALL remnant rather than blindly incising (b).

Figure 2

Photograph demonstrating the 30-degree hyperlordotic cage with attached screws to prevent ventral migration into the peritoneum.

Figure 3

(a) Pre- and (b) postoperative standing 36 inch lateral radiographs demonstrating improvement in sagittal vertical axis after two-level ALR plus multilevel MIS LIF with open posterior instrumentation.

Figure 4

Graph demonstrating pre- and postoperative values for lumbar lordosis (LL), sagittal vertical axis (SVA), and pelvic tilt (PT) in our cohort.

Figure 5

Graph demonstrating pre- and postoperative values for visual analogue scale (VAS) and Oswestry Disability Index (ODI).