Posterolateral Versus Posterior Interbody Fusion in Lumbar Degenerative Spondylolisthesis

Study Design: This was a retrospective study of 2 different fusion techniques for the treatment of lumbar degenerative spondylolisthesis. Objective: To determine whether posterior lumbar interbody fusion (IF) is associated with improved patient-rated satisfaction and functional outcome when compared with posterolateral fusion (PLF). Summary of Background Data: IF and PLF are widely used surgical approaches in the treatment of spondylolisthesis. Numerous studies have compared IF and PLF techniques, but inconsistent results, heterogeneous cohorts, and conflicting scientific evidence have made it difficult to reach a consensus on the optimal fusion technique. Materials and Methods: A consecutive cohort of 87 patients who had single-level degenerative spondylolisthesis and either PLF or IF were identified from a prospectively maintained database. Short Form-36 physical and mental component score, Oswestry Disability Index, back and leg pain, and complication rate were assessed to 24 months postoperatively. Patient characteristics, clinical outcome, and complications were compared between groups. Results: Of the 87 patients identified, 29 patients (33%) had PLF and 58 patients (67%) had IF. Patient follow-up was >= 85%. Foraminal stenosis (PLF, 13.8% vs. IF, 34.5%; P = 0.046) was more common among the participants in the IF group. Intraoperative and postoperative complications were not different between groups (P > 0.05). The reoperation rate was 3.4% in the PLF group and 10.3% in the IF group (P = 0.416). Patients in the PLF group experienced similar gains in improvement in all outcome measures as those in the IF group (P > 0.05). Four patients in the IF group and 3 in the PLF group were lacking evidence of radiographic fusion. These patients did have increased moderate back pain compared with patients demonstrating radiographic fusion but did not differ in any other postoperative outcomes measures. Conclusions: Type of fusion, IF or PLF, does not affect patient outcome or postoperative complication rates.