Lateral Access Spine Surgery
Patients with back pain necessitating lumbar spinal fusion procedures have historically required extensive operations resulting in significant blood loss, post-operative pain, and a prolonged hospital stay with physical rehabilitation. Recent innovative advances in minimally invasive lateral access spinal techniques are now enabling surgeons to perform these same procedures in a safe and effective muscle sparing manner. This contemporary approach provides significant pain relief to patients who have lived with back and/or leg pain for years and have not responded favorably to conservative treatments such as physical therapy, steroid injections, or pain medications.
The lateral transpsoas retroperitoneal approach can be performed for a variety of conditions including degenerative disc disease, recurrent disc herniation, spinal instability, spondylolisthesis, pseudoarthrosis, osteomyelitis/discitis, post-laminectomy syndrome and trauma. Further advances have more recently expanded patient candidacy to include anterior and lateral tumors of the thoracolumbar spine as well as those with debilitating spinal deformity (scoliosis). However, patient screening and selection is integral, as not all patients are suitable candidates for the lateral approach (e.g., patients with severe stenosis secondary to facet hypertrophy or other dorsal compressive disease states may require posterior access for safe and effective treatment).
Artist rendering (left) and intra-operative image (right) of minimally invasive lateral access retractor system inserted through a 3 cm flank incision. Note the large width of the interbody implant in right image (arrow) thus enabling a greater surface area for fusion and improved long term stability.
Traditional posterior fusion techniques require the dissection and retraction of back muscles, bones, vessels, ligaments, and nerves; whereas traditional anterior approaches through the abdominal musculature risk injury to major vascular structures such as the aorta and iliac vessels, as well as the very delicate genitourinary structures. The lateral transpsoas approach enables the means to reproducibly address spinal pathology from the side of the patient, (utilizing novel dynamic real-time nerve localizing and monitoring techniques, thus minimizing surrounding tissue trauma and maximizing safety and efficacy.
Lumbar interbody fusions attempt to eliminate the instability caused by degenerated discs and facet joints that result in vertebral slippage, loss of natural disc height, and pinching of the traversing spinal nerve roots. The direct lateral approach enables liberal access to these disc spaces, thus permitting the placement of extremely large interbody implants that indirectly restore natural disc height and decompress the spinal nerve roots via ligamentotaxy.
The procedure is performed through a 3 cm incision located in the lateral flank of the patient. Surgical dissection is performed via the placement of serial dilators, each of which actively provides directional nerve localizing electromyographic (EMG) data to the surgeon for safe navigation near the lumbar nerve plexus. Active neuromonitoring in addition to the use of real-time fluoroscopic guidance insures safety and accuracy as the expandable tubular retractor is carefully advanced through the psoas muscle to the desired disc space or vertebral body. Once the retractor system is secured, the disc material or pathologic tissue is removed and a large interbody spacer is placed (see images above). Dramatic widening of the collapsed disc space and stenotic foramen are clearly observed when comparing pre-operative to post-operative radiographs. In some cases, supplemental screws are required to increase the fusion construct’s stability. These can either be placed through the same lateral incision and/or in a posterior percutaneous minimally invasive fashion.
Typically, healthy patients are able to walk again within hours of the lateral procedure’s completion, and many are discharged from the hospital after a short one- or two-day stay. Although the learning curve is steep, with experience and mastery, minimally invasive lateral access techniques can result in dramatically reduced operating times, blood loss, recovery period, and pain—getting patients back on their feet faster and safer than ever.