Structural and Funcional Outcomes of Extreme Lateral Interbody Fusion (XLIF) Compared to Posterior Lumbar Interbody Fusion (PLIF)

Since the first successful spinal fusion surgery using a modern stabilization technique in 1909, surgical fusion has become one of the most commonly performed procedures for degenerative disease of the lumbar spine. The incidence of lumbar spinal fusion for degenerative conditions has more than doubled from 2000 until 2009. Despite the high incidence of fusion surgery, the decision making in lumbar fusion surgery is complicated by a wide variety of indications (the greatest measured in any surgical procedure). This could indicate there might be an overuse of lumbar fusion. However, decompression alone, or non-operative care for degenerative conditions may risk progressive spinal instability, intractable pain, and neurological impairment. These complications in the absence of fusion surgery, clearly demonstrate the beneficial effects of adding spinal fusion surgery. Because of its beneficial effect and high usage, it is of greatest importance to reduce postoperative disability and pain, by diminishing surgical invasiveness.

Traditional open posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) are used to treat degenerative diseases of the spinal column. These techniques require an extensive dissection of the paraspinal musculature, which in term can lead to muscle denervation, loss of function, muscular atrophy, and spinal instability. It has also been known that paraspinal muscle damage induced during surgery is related to long term disability and pain. With this knowledge, minimally invasive spine surgery began to develop in the mid-twentieth century. Since then, new direct approaches to the lumbar spine, known as lumbar lateral interbody fusion (LLIF), direct lateral interbody fusion (DLIF), or extreme lateral interbody fusion (XLIF), have been introduced.

This study will focus on XLIF. Ozgur. 2006 first reported the XLIF procedure, as a minimally invasive procedure that approaches the spine from the lateral via the space between the 12th rib and the highest point of the iliac crest. This approach allows direct access to the intervertebral disc space without disruption of the peritoneal structures or posterior paraspinal musculature. Ohba. 2017 compared XLIF with percutaneous pedicle screws to traditional PLIF, and found that PLIF was associated with less intraoperative blood loss, postoperative white blood cell (WBC) counts, C-reactive protein (CRP) levels, and creatine kinases (CK) levels, indicating less muscle damage. Postoperative recovery of performance was significantly faster in the XLIF group. 1-year disability and pain scores were also significantly lower in the XLIF group. Despite these significant better results reported in the XLIF group, the systematic review of Barbagallo. 2015 concluded that there is insufficient evidence of the comparative effectiveness of lateral lumbar interbody fusion (XLIF) versus PLIF/ TLIF surgery. This indicates that the evidence for choosing between XLIF or a traditional approach is still scarce, and no recommendations can be made.

This study will focus on comparing XLIF to PLIF. The objective of this study is to compare clinical and structural outcome measures between the XLIF and PLIF groups, to confirm our hypothesis that the minimally invasiveness of the XLIF technique facilitates a significant faster post-operative recovery, and improves functional and structural outcomes.