Comparison of multifidus muscle atrophy after posterior lumbar interbody fusion with conventional and cortical bone trajectory

Objective: To determine if minimally invasive posterior interbody fusion with cortical bone trajectory (CBT) is associated with reduced paraspinal muscle damage compared to conventional open posterior lumbar interbody fusion (PLIF). Methods: Sixteen consecutive patients who underwent CBT were grouped into matched pairs with 16 patients who underwent conventional PLIF between May 2013 and January 2014, in terms of age, sex, body mass index, and spinal levels. Perioperative data and clinical data, including the Japanese Orthopedics Association (JOA) score, visual analogue scale (VAS) score, Oswestry Disability Index (ODI),before and after surgery were evaluated. Magnetic resonance imaging was performed preoperatively and 6 months postoperatively. The fat infiltration ratio was calculated. Results: Thirty-two patients with an 18-month follow-up period were evaluated. Clinical improvement, indicated by the VAS score for back and leg pain, ODI, and JOA score, was significant in both groups. However, there were no significant differences in operative time, blood loss, hospital stay duration, and recovery rate between the groups. The fat infiltration ratio was lower in the CBT group (p < 0.05) than in the conventional PLIF group. Conclusions: CBT is comparable with conventional PLIF with respect to short-term clinical outcomes but induced less multifidus muscle damage. (C) 2016 Published by Elsevier B.V.