Chapter 37 Lateral Interbody Fusion Using the Xlif System

Luiz M. Pimenta, MD, PhD, Carlos F. Arias, MD, Juliano Lhamby, MD, Leonardo Oliveira, BSc, Thomas Schaffa, MD, Etevaldo Coutinho, MD

Building on the concept and technique of minimally invasive spinal approaches [1], we have developed the eXtreme Lateral Interbody Fusion (XLIF, NuVasive, Inc., San Diego, CA) approach to the lumbar spine. In contrast to the more traditional anterior lumbar interbody fusion (ALIF) method of approaching the disc anteriorly through the abdomen for implantation of cages and other devices, we have developed the XLIF technique, which accesses the disc laterally through the psoas muscle (Fig. 37-1). This approach offers adequate access to the disc space with the added benefit of reduced iatrogenic injury to abdominal vascular structures (aorta and vena cava), the sympathetic plexus (reducing incidence of retrograde ejaculation), and neural structures (namely, the spinal nerves that cross the posterior aspect of the psoas muscle). The technique employs muscle dilation through the fibers of the psoas muscle in an area approximately 3 cm in diameter.

Figure 37–1 Direction of a lateral trans–psoas approach to the lumbar spine in comparison with conventional anterior and posterior approaches.

Preoperative planning

As is appropriate for all patients who undergo a surgical procedure, we recommend preoperative medical and cardiovascular evaluations. In addition, preoperative radiographs help define potential problems with the approach trajectory. For example, if the operative level will be L4-L5, the height of the iliac crest should be checked to see that there will be clearance into the disc space. All L4-L5 levels can be accessed laterally with appropriate patient positioning on a bendable surgical table. At upper levels, determination of rib location helps prevent any unsuspected surprises during the approach. At L1-L2, either the lower rib may need to be elevated superiorly away from the approach or an intercostal approach may be necessary.

Indications

Indications for the XLIF technique are the same as those for any interbody fusion, with the limitation of access only at disc levels above L5. Such patients typically suffer discogenic pain due to segmental instability, disc degeneration, degenerative scoliosis, and/or grade I or II spondylolisthesis [2–7]. It may also be applied to patients in whom prior decompressive surgery (i.e., discectomy and/or laminectomy) have failed and who therefore require interbody fusion, and in cases of adjacent-level disease after prior fusion surgery, because in these revision cases, scarring may limit the ability to safely perform a more traditional fusion approach. Revisions of failed interbody fusions and failed lumbar total disc replacements have also been treated with the XLIF approach for retrieval and revision.

The XLIF approach has been successfully accomplished for levels above and including L4-L5. Approaching the L5-S1 level with this technique is not recommended because of the risk of damage to the iliac blood vessels as well as the difficulty of accessing the disc space because of the iliac crest. For the L5-S1 level, it is easier to use a mini-open retroperitoneal approach or minimally invasive posterior approach.

Instrumentation

The instruments necessary for performing the XLIF procedure are as follows:

MaXcess System of dilators and split-blade retractor (Fig. 37-2A; NuVasive, Inc.). Consists of bifurcated light cable, articulating arm, retractor system with various length blades, and blade-extension shims.