Grade II spondylolistheses were most commonly present at L4-5 (97%), though in a single level each, L2-3, and L3-4 were indicated. A total of 80 levels (1.3 per patient) were treated (63 for grade II spondylolisthesis). One-, two-, and three-level procedures were performed in 78%, 18%, and 5% of cases, respectively. Biologic materials varied, but most included demineralized bone matrix (87%). Transpedicular fixation was used in all but one instance of grade II spondylolisthesis, where transpedicular facet fixation was used. Treatment variables are included in .
It is important to remember that Lateral Recess Stenosis and Axial Stenosis are related conditions. Lateral Recess Stenosis commonly occurs in the lumbar spine region of the lower back at vertebral levels L4/5 & L5/S1, and in the neck at vertebral levels C5/6 & C6/7. Axial Stenosis however commonly occurs in the lumbar spine region of the lower back at vertebral levels L2/3 & L3/4 and in the neck at vertebral levels C4/5 & C5/6. The significant benefit offered by aware state diagnosis (see below) is that it enables the surgeon to accurately target the problem area and thus deliver specific treatment focused only upon that problem area.
Spondylolisthesis is one of the most common indications for spinal surgery. However, no one approach has been proven to be more effective in treating spondylolisthesis. Recent advances in minimally invasive spine technology have allowed for different approaches to be applied to this indication, notably extreme lateral interbody fusion (XLIF). The risk, however, of using XLIF in treating grade II spondylolisthesis is the ventral position of the lumbar plexus, particularly at L4-5. Objective. This study reports the safety and midterm clinical and radiographic outcomes of patients with grade II lumbar spondylolisthesis treated with XLIF. Methods. 63 patients with grade II spondylolisthesis and spinal stenosis were treated with XLIF and were available for 12-month followup. Of those, 61 (97%) were treated at L4-5. Clinical (VAS, complications, and reoperation rate) and radiographic (anterolisthesis, disk height, and fusion) parameters were assessed. Study Design. Data were collected via a prospective registry and analyzed retrospectively. Results. Sixty-three patients were available for evaluations at least one year postoperatively. Average pain (visual analog scale) decreased from a score of 8.7 at baseline to 2.2 at 12 months postoperatively. Average anterior slippage was reduced by 73% and was well maintained. Average disk height (4.6mm pre-op and 9.0mm post-op) nearly doubled after surgery. Slight settling (average 1.3mm) occurred over the twelve-month follow-up period. There were no neural injuries and no nonunions noted. Conclusions. XLIF is a safe and effective minimally invasive treatment alternative for grade II spondylolisthesis. Real-time neurological monitoring and attention to technique are mandatory.
Standing anteroposterior (AP), static lateral, and flexion-extension lateral radiographs were obtained preoperatively and at two weeks, three months, six months, and twelve months after surgery. Measurements of disk height (mm) and anterolisthesis (mm) were taken. Spinal stenosis was confirmed by preoperative CT or MR imaging. Radiographic analysis was performed by a physician other than the operating surgeon.
Fusion was defined as the presence of bridging bone across the disk space (modified Lenke grade 1 or 2)  and the absence of significant motion (mm interspinous widening) on dynamic radiographs.
Nonetheless, neurologic deficits associated with lateral approaches are an area of great discussion. As has been documented anatomically and radiographically, the lumbar plexus migrates ventrally as one descends caudally from L2-3 to L4-5 [, –]. This places the plexus at greatest risk in a transpsoas approach at the L4-5 level. In addition, anterolisthesis of the superior vertebral body carries the plexus even more ventral, heightening safety concerns. However, as shown by our data, in the presence of real-time neurologic monitoring and with attention to the details of the technique mentioned above, grade 2 listhetic segments, especially at L4-5, can be treated successfully without neurologic injury. The importance of monitoring and technique cannot be overemphasized.