The extreme lateral minimally invasive approach to pure degenerative lumbar disk disease

Although significant technical progress has been made in spine surgery over the last decade, interbody fusion techniques for degenerative disk disease (DDD) are still a controversial indication in the current literature [1–7]. Good clinical results have been reported in several randomized clinical trials for a variety of fusion procedures in the treatment of lumbar DDD, with visual analog scale (VAS) improvement of 22–77 % and Oswestry Disability Index (ODI) improvement of 19–79 % [7, 8]. In our opinion, the lack of clear indications in the treatment of lumbar DDD and the opportunity to fuse may be partially attributed to the invasiveness of open surgical approaches, which often seem to be overly aggressive procedures for a disease that has been shown to benefit even from conservative treatment [9]. Nevertheless, the emerging diffusion of minimally invasive spine techniques is progressively changing the indication for treating patients with lumbar DDD because they can achieve mono- or plurisegmental interbody fusion, allowing much faster recovery with a very low rate of complications. The lateral minimally invasive approach to lumbar spine surgery is an alternative minimally invasive technique for performing interbody fusion at levels above L5. Lateral interbody fusion (LIF) was first described in 2001 by Pimenta et al. and became popular among spine surgeons because of its theoretical advantages over both posterior and anterior approaches [10–12]. Few studies have reported good short- or middle-term outcomes specifically for patients with lumbar DDD following LIF, but its benefits include less tissue dissection with preservation of bony and ligamentous structures; smaller incisions; decreased operative time, blood loss, hospital stay, and postoperative pain; and enhanced fusion rate due to the possibility of placing a footprint intervertebral cage larger than TLIF and PLIF cages [11, 13–23]. The main reported risk of such an approach is damage to the lumbar nerves along the lateral side of the lumbar vertebral column inside the major psoas muscle, which is violated and dissected. As not all patients with lumbar DDD could benefit from LIF, it should be proposed in only select cases, and knowledge about the anatomical distribution of lumbar nerves and electrophysiological monitoring during surgery are mandatory to avoid surgical complications.