The XLIF (eXtreme Lateral Lumbar Interbody Fusion) is an approach to spinal fusion in which the surgeon accesses the intervertebral disc space and fuses the lumbar spine (low back) using a surgical approach from the side (lateral) rather than from the front (anterior) or the back (posterior).
The XLIF approach allows for anterior access to the disc space without an approach surgeon or the complications of an anterior intra-abdominal procedure 1).
The XLIF is one of a number of spinal fusion options that a surgeon may recommend to treat specific types of lumbar spinal disorders, such as lumbar degenerative disc disease, spondylolisthesis, scoliosis and deformity and some recurrent lumbar disc herniations and types of lumbar stenosis. It cannot be used for all types of lumbar conditions for which spinal fusion is a treatment option. For example, it cannot treat conditions at the lowest level of the spine, L5-S1 or for some people at L4-L5.
Whilst the available data is limited, minimally invasive XLIF procedures appear to be a promising alternative for the treatment of scoliosis, with improved functional VAS and Oswestry disability index outcomes and restored coronal deformity. Future comparative studies are warranted to assess the long term benefits and risks of XLIF compared to anterior and posterior procedures 2).
Reports of XLIF fusion rate in the literature vary from 85 to 93 % at 1-year follow-up 4).
Transient ipsilateral thigh numbness, pain and/or hip flexor weakness is a frequent post-operative finding most commonly when the L4-5 level is instrumented. Dense femoral nerve palsy is a debilitating complication that may occur despite intra-operative neurophysiologic monitoring 5).
A anatomical study suggests that positioning the dilator and/or retractor in a posterior position of the disc space may result in nerve injury to the lumbosacral plexus, especially at the L4-5 level. The risk of injuring inherent nerve branches directed to the psoas muscle as well as injury to the genitofemoral nerve do still exist 6).
A retrospective review found six patients who met strict operative criteria including instability, intractable pain, neurological deficit, and disease progression. All patients were non-ambulatory before surgery because of intractable back pain. The patients underwent standard lateral minimally invasive surgery using either the extreme lateral interbody fusion (NuVasive, San Diego, CA, USA) or direct lateral interbody fusion (Medtronic Sofamor Danek, Memphis, TN, USA) system. The patients underwent debridement with a discectomy and partial or complete corpectomy, with polyetheretherketone or titanium cage placement. Two patients had additional posterior fixation with percutaneous pedicle screws, and none had immediate perioperative complications. The postoperative CT scans demonstrated satisfactory debridement and hardware placement. All patients experienced significant pain improvement and could ambulate within a few days of surgery. So far, the 1year follow-up data have demonstrated stable hardware with solid fusion and continued pain improvements. One patient demonstrated hardware failure secondary to refractory infection, 2months postoperatively, and required additional posterior decompression and debridement with pedicle screw fixation. The lateral transpsoas approach permits debridement and fixation coupled with percutaneous pedicle screw fixation to further stabilize the spine in a minimally invasive fashion. Due to the significant comorbidities in this patient population, a minimally invasive approach is a suitable surgical technique. A close follow-up period is necessary to detect early hardware failure which may necessitate more extensive treatment 7).