Single segment of posterior lumbar interbody fusion for adult isthmic spondylolisthesis: reduction or fusion in situ.

Objective: We prospectively compared surgical reduction or fusion in situ with posterior lumbar interbody fusion (PLIF) for adult isthmic spondylolisthesis in terms of surgical invasiveness, clinical and radiographical outcomes, and complications.
Methods: From January 2006 to June 2008, 88 adult patients with isthmic spondylolisthesis who underwent surgical treatment in our unit were randomized to reduced group (group 1, n = 45) and in situ group (group 2, n = 43), and followed up for average 32.5 months (range 24-54 months). The clinical and radiographical outcomes were compared between the two groups.
Results: The average operative time and blood loss during surgery showed insignificant difference (p > 0.05) between two groups. The radiological outcomes were significantly better in group 1, but there was no significant difference between two groups of clinical outcomes, depicting as VAS, ODI, JOA and patients' satisfaction surveys. Incident rate of surgical complications was similar in two groups, but in group 1 the complication seemed more severe because of two patients with neurological symptoms.
Conclusions: For the adult isthmic spondylolisthesis without degenerative disease in adjacent level, single segment of PLIF with pedicle screw fixation is an effective and safe surgical procedure regardless of whether additional reduction had been conducted or not. Better radiological outcome does not mean better clinical outcome.