Mini-transforaminal lumbar interbody fusion versus anterior lumbar interbody fusion augmented by percutaneous pedicle screw fixation: A comparison of surgical outcomes in adult low-grade isthmic spondylolisthesis

STUDY DESIGN: Retrospective clinical data analysis. OBJECTIVE: To compare clinical results with radiologic results of 2 fusion techniques for adult low-grade isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: There is clear evidence that lumbar interbody fusion using anterior and posterior approaches provides a high fusion rate, good sagittal alignment, and good clinical outcomes. However, there are no recent studies that compare these 2 fusion techniques. METHODS: Between March 2004 and December 2004, 48 patients underwent instrumented mini-anterior lumbar interbody fusion (ALIF) and 46 underwent instrumented mini-transforaminal lumbar interbody fusion (TLIF). The mean follow-up periods were 32.6 and 29.7 months, respectively. RESULTS: The mean visual analog scale (VAS) scores for back and leg pain decreased, respectively, from 7.7 and 7.5 to 2.9 and 2.7 in the ALIF group and from 7.0 and 6.3 to 2.3 and 2.2 in the TLIF group. The mean Oswestry disability index (ODI) scores improved from 51.4% to 23.2% in the ALIF group and from 52% to 14.4% in the TLIF group. In both groups, the VAS and ODI scores significantly changed preoperatively to postoperatively (P<0.001). However, statistical analysis showed no significant difference in postoperative VAS/ODI scores between groups. Radiologic evidence of fusion was noted in 95.8% and 92.3% of the patients in the ALIF group and the TLIF group, respectively. In both the groups, changes in the disc height, segmental lordosis, degree of listhesis, and whole lumbar lordosis (WL) between the preoperative and postoperative periods were significant except for WL in the TLIF group. The amount of change between preoperative and postoperative disc height, segmental lordosis, and WL demonstrated significant intergroup differences (P<0.05). CONCLUSIONS: The mini-ALIF group demonstrated key radiographic advantages compared with the mini-TLIF group for adult low-grade isthmic spondylolisthesis. However, clinical and functional outcomes did not demonstrate significant differences between groups.