Posterior open‐wedge anterior longitudinal ligament release (POWAR): cadaveric technique analysis

Introduction

Anterior column release is a powerful surgical technique for achieving spinopelvic balance in adult patients with sagittal plane deformities. We present an alternative strategy for focal deformity correction from a posterior‐only approach. The purpose of this study was to evaluate the feasibility and efficacy of a novel surgical technique called posterior open‐wedge diskectomy and anterior longitudinal ligament (ALL) release (POWAR).

Materials and Methods

A cadaveric torso underwent POWARs at the L1‐L4 intervertebral disc spaces. Baseline measurements of end‐plate angle (EPA), anterior intervertebral disc height (ADH), and posterior intervertebral disc height (PDH) were obtained. These measurements were repeated after three stages of correction: posterior column compression alone, posterior column compression following Schwab grade 2 osteotomies, and posterior column compression following POWAR. A second cadaver underwent posterolateral spinal dissection to demonstrate the pertinent anatomical features relevant to this novel procedure.

Results

With each stage of correction, a sequential increase in EPA and ADH and a decrease in PDH were demonstrated. The large increase in ADH seen following POWAR confirmed successful release of the ALL. In situ investigation of the aorta and inferior vena cava following anterior exposure revealed no injury to the great vessels or surrounding structures. Ex vivo testing of the aorta and inferior vena cava took place at the L3‐4 level. This testing demonstrated no injury or tears to either vessel.

Conclusions

POWAR is a new surgical technique that can provide an alternative to three‐column osteotomy for surgeons performing spinal reconstructions in adults through an open, posterior‐only approach.

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