Anterior lumbar interbody fusion for the management of chronic lower back pain: current strategies and concepts.

In a retrospective analysis of two large multicenter clinical studies, 321 patients with degenerative lumbar disc disease were divided into two groups who underwent anterior lumbar interbody fusion using two threaded titanium fusion cages. To determine whether differences in surgical procedures and cage design affect anterior and posterior annular distraction and clinical outcomes, the authors evaluated the clinical and radiographic outcomes of patients treated with a stand-alone ALIF procedure. End-plate preservation techniques were associated with improved anterior and posterior disc space distraction compared with standard end-plate preparation techniques. Similarly, the use of the LT-CAGE device led to greater improvements in restoration of segmental lordosis than did the use of standard cylindric cages. Furthermore, these surgical benefits resulted in improved clinical outcomes as early as 3 months and were maintained over a 2-year follow-up period in patients with improved postoperative disc space distraction and lordosis. Placing cylindric cages in a lordotic or trapezoidal disc space can be accomplished only through asymmetric reaming of the vertebral end plates. In a lordotic disc space, the posterior portion of the disc must be reamed more than the anterior portion. This over-reaming inhibits distraction of the posterior disc space and limits restoration of neuroforaminal height. Reduced reaming and symmetric reaming of the vertebral end plates enable the surgeon to restore anatomic segmental lordosis across the disc space. The tapered cage configuration aids in maintaining segmental lordosis. Anatomic restoration of disc space contours has an impact on a patient's outcome after stand-alone anterior interbody fusion surgery.