Clinical and radiological outcomes of unilateral transforaminal lumbar interbody fusion

Abstract

Background Interbody fusion techniques provide solid fixation, maintain the load-bearing capacity of the spine, maintain proper disc and foraminal heights, have higher fusion rates, and prevent implant failure. Unilateral transforaminal lumbar interbody fusion (TLIF) is a one-stage posterior approach to the disc space that allows unilateral larger cage insertion without violation of the spinal canal by avoiding dural retraction, which is advantageous in revision cases and in higher lumbar levels above L3. Aim The aim of the study was to describe the technique and study the clinical and radiological results of unilateral TLIF. Study design This is a retrospective study on 40 patients with different etiologies treated by unilateral TLIF. Patients and methods A retrospective analysis was performed on 40 patients who had undergone unilateral TLIF during the period from April 2006 to December 2008 for chronic low back pain and radicular leg pain of different etiologies, including isthmic and degenerative spondylolisthesis, and revision cases with failed conservative treatment of more than 3 months. Radiographic assessment was carried out by means of anteroposterior, lateral, and dynamic flexion-extension plain radiographs and MRI. Bony fusion was assessed using the Bridwell anterior fusion grading system. Functional assessment was made using the visual analogue scale (0-10) for back and leg pain and the Oswestry Disability Index questionnaire. Results Unilateral TLIF achieves statistically significant reduction in spondylolisthesis from an average of 35.55 ± 11.62% preoperatively to an average of 3.49 ± 3.29% postoperatively with minimal change seen at final follow-up with restoration of segmental lordosis in all patients. Disc and foraminal heights were restored and corrected from an average of 7.24 ± 1.30 and 13.53 ± 1.91 mm, respectively, preoperatively to 11.80 ± 1.075 and 19.76 ± 1.79 mm, respectively, postoperatively without significant change at last follow-up. Ninety percent of patients had G1 bony fusion and 10% had G2 bony fusion. No patient had G3 or G4 fusion. All patients showed significant postoperative improvement in leg and back pain immediately postoperatively and at last follow-up. Leg pain improved from 7.24 ± 0.61 to 2.26 ± 0.84 SD postoperatively and to 0.65 ± 0.70 SD at last follow-up, and back pain improved from 7.78 ± 0.86 to 2.76 ± 0.89 SD postoperatively and to 0.98 ± 0.75 SD at last follow-up. The average preoperative Oswestry Disability Index score improved from 54.95 ± 7.02 to 10.73 ± 3.28 SD at last follow-up. There were no major intraoperative complications. Conclusion Unilateral TLIF s a safe and effective technique. It provides good clinical and radiological outcomes in different lumbar spinal pathologies. It is especially effective and safe in revision cases with epidural fibrosis when the standard posterior lumbar interbody fusion technique is contraindicated.