Minimally Disruptive Lateral Transpsoas Approach for Thoracolumbar Anterior Interbody Fusion

Abstract

The minimally disruptive lateral approach for thoracolumbar interbody fusion was developed as an alternative to conventional anterior lumbar interbody fusion (ALIF), maximizing ALIF’s benefits while avoiding many of the risks of the approach. The minimally invasive lateral interbody fusion approach utilizes a transpsoas approach to the lateral disc space, 90° from midline, under direct visualization through retroperitoneal access and blunt dissection. The nerves of the lumbar plexus may be monitored during the approach and procedure. Some surgeons (including these authors) choose to employ surgeon-directed, directionally stimulating electromyography with discrete-threshold feedback integrated into access and procedural instrumentation. The potential for injury is thereby mitigated to a large degree with these neuromonitoring platforms providing geographic information about motor nerves relevant to the approach. Once the disc space is accessed, conventional surgical disc preparation techniques are used prior to implant placement, with care to preserve the cortical annular ring of the vertebral end plate and to appropriately size the intervertebral cage. The lateral transpsoas approach allows for placement of a large interbody implant, covering the lateral borders of the apophyseal ring and providing a wide fusion surface area, while leaving the anterior and posterior longitudinal ligaments intact. Anterolateral plating can be used for a single-incision approach to interbody fusion and fixation, or a variety of supplemental fixation can be placed through additional incisions while the patient remains in the lateral decubitus position (unilateral pedicle screw fixation on the side ipsilateral to the approach, bilateral facet fixation, spinous process plating). The minimally invasive lateral interbody fusion procedure is a versatile approach to lumbar interbody fusion and appears to have similar outcomes to conventional anterior and posterior approaches with less perioperative morbidity.