by Richard J. Nasca M.D.
Spinal fusion procedures are indicated for various disorders, deformities and injuries of the lumbar spine. The Albee and Hibb’s fusions for progressive deformities due to tuberculosis were performed in the early 1900’s. The anterior and posterior Interbody fusion techniques were popularized in the 1940’s and 1950’s. The Harrington rod for correction of scoliosis was a milestone invention which was poorly received by the orthopaedic community in the 1950’s. Pedicle screw fixation popularized in Europe was introduced in the US in the early 1980’s and meet with a great deal of resistance and skepticism from both neurosurgical and orthopaedic surgeons. In addition, a great deal of litigation was generated by some poor patient outcomes and a consortium of Philadelphia based plaintiff’s attorneys. In the mid 1980’s, metallic interbody cages were developed to stabilize the spine and contain the bone grafts used for fusion. In the late 1990’s percutaneous approaches to performing spine fusions and inserting spine fixation devices were developed. Modifications in the posterior interbody approach of Paul Cloward were made by Jurgen Harms. His method referred to as a transforaminal lumbar interbody fusion (TLIF) required facet joint removal and distraction to facilitate access into the disc space for the placement of bone grafts with titanium cages.
Shortly after the turn of the century a less invasive approach to the lumbar spine called an extreme lateral interbody fusion (XLIF) was described by Ozgur, Aryan, Pimenta and Taylor. This approach allows access to the lateral spine thru a small incision in the flank for insertion of cages and spine fixation. The L5-S1 level is not accessible with the XLIF technique.
Andrew Cragg, an interventional radiologist described an axial presacral approach to the sacrum in 2004. The AxiaLIF rod and instrumentation were developed by TranS1, Wilmington, NC. This technique provides access to the L5- S1 disc for interbody fusion by an axial portal drilled through the sacrum. After removal of the disc remnants, the end plates are prepared with Nitinal cutters. Bone grafts from the reamings and bone extenders are used to promote the interbody fusion. The AxiaLIF rod is used to stabilize the L5-S1 segment after preparing an axial tract in L5. The procedure has been used in patients with spondylolisthesis, spinal stenosis, degenerative disc disease and its variants, lumbosacral scoliosis as an anchor across L5 –S1 to enhance stability for fusion in long constructs, herniated nucleus pulposus and revision surgery. Pedicle and/or facet screws are used to supplement the fixation.
Although the AxiaLIF approach and method of preparing the disc space for interbody fusion has generated skepticism ,the results from the procedure are encouraging with fusion rates of 90+%, complications of less than 1%, lessened hospital stay, blood loss and operative time when compared with more traditional interbody fusion techniques.