Posterior spinal fusion for lumbar degenerative diseases using the Crock-Yamagishi (C-Y) spinal fixation system

Although many transpedicular screw systems have been developed and have undergone wide clinical use, experience with semirigid transpedicular systems has rarely been reported. We evaluated the efficacy and safety of the Crock-Yamagishi (C-Y) system for posterior spinal fusion in lumbar degenerative diseases. The outcomes for 26 patients (14 men, 12 women) with lumbar degenerative diseases who underwent posterior spinal fusion using the C-Y system were analyzed (posterior lumbar interbody fusion (PLIF), 11 patients; posterolateral fusion (PLF), 14; and facet fusion (FF), 1. Symptoms were evaluated using the Japanese Orthopaedic Association Assessment of Treatment for Low Back Pain (JOA score). Preoperative scores ranged from -1 to 23 points (mean, 12.8), while postoperative scores ranged from 19 to 29 points (mean, 26.4). Degree of recovery ranged from 23.1% to 100% (mean, 83.2%). Overall fusion rate was 96.2% (25/26). Neither breakage nor loosening of implants was observed radiographically. Intra- and postoperative complications included one case of transient L5 nerve root palsy attributable to surgical technique, and one deep postoperative infection. The C-Y system, categorized as semirigid, is effective when used with one- or two-level PLIF or PLF for lumbar degenerative disorders, grade I to II spondylolisthesis, and failed back syndrome.