Clinical outcomes of lumbar degenerative disc disease treated with posterior lumbar interbody fusion allograft spacer: a prospective, multicenter trial with 2-year follow-up.

The clinical benefits and complications of posterior lumbar interbody fusion (PLIF) have been studied over the past 60 years. In recent years, spine surgeons have had the option of treating low back pain caused by degenerative disc disease using PLIF with machined allograft spacers and posterior pedicle fixation. The purpose of this clinical series was to assess the clinical benefits of using a machined PLIF allograft spacer and posterior pedicle fixation to treat degenerative disc disease, both in terms of fusion rates and patient outcomes, and to compare these results with those in previous studies using autograft and metal interbody fusion devices. Results were also compared with results from studies using transverse process fusion. This prospective, nonrandomized clinical series was conducted at 10 US medical centers. Eighty-nine (55 male, 34 female) patients underwent PLIF with a presized, machined allograft spacer and posterior pedicle fixation between January 2000 and April 2003. Their outcomes were compared with outcomes in previous series described in the literature. All patients had experienced at least 6 months of low back pain that had been unresponsive to nonsurgical treatment. Physical examinations were performed before surgery, after surgery, and at 4 follow-up visits (6 weeks, 6 months, 12 months, 24 months). At each interval, we obtained radiographs and patient outcome measures, including SF-36 Bodily Pain Score, visual analog scale pain rating, and Oswestry Disability Index. The primary outcome was fusion results at 12 and 24 months; the secondary outcomes were pain, disability, function/quality of life, and satisfaction. One-level PLIFs were performed in 65 patients, and 2-level PLIFs in 24 patients. Flexion-extension radiographs at 12 and 24 months revealed a 98% fusion rate. Of the 72 patients who reached the 12-month follow-up, 86% reported decreased pain and disability as measured with the Oswestry Disability Index. Decreased pain as measured with the SF-36 Bodily Pain Score was reported by 74% of patients who reached the 12-month follow-up. The graft-related complication rate among all patients who underwent PLIF was 1.61%. When performed with machined allograft spacers and posterior pedicle fixation, PLIF is a safe and effective surgical treatment for low back pain caused by degenerative disc disease. The patients in this clinical series had outcomes equal or superior to the outcomes in previous series.