Anterior interbody fusion with and without interspinous block implementation for lumbar isthmic spondylolisthesis.

The clinical and radiographic results of lumbar isthmic spondylolisthesis were compared between interspinous block-assisted anterior interbody fusion (block-assist group, n = 16) and anterior interbody fusion with no use of the block (nonassist group, n = 17) with an average follow-up of 7 years (range 1 1/3-13 years). Satisfactory relief of low-back pain, significantly early interbody union (union rate 88%, p < 0.05), and spontaneous fusion of pars defect (fusion rate 44%, p < 0.05) were obtained in the block-assist group. In the nonassist group, interbody union was markedly delayed (p < 0.05), the union rate was 53%, and spontaneous fusion of the pars was found in 12% of patients. The overall clinical results at final follow-up in both groups did not show a statistically significant difference, but the results tended to be superior in the block-assist group.