Interspinous process devices for the treatment of neurogenic intermittent claudication: a systematic review of randomized controlled trials

The aim of this study is to compare interspinous process device (IPD) implantation to other methods for the treatment of neurogenic intermittent claudication (NIC). PubMed and Cochrane library were searched in December 2014. Randomized controlled trials (RCTs) comparing IPD implantation and nonoperative therapy or laminectomy with/without spinal fusion for the treatment of NIC due to spinal stenosis or low-grade degenerative spondylolisthesis were included. Meta-analysis and qualitative analysis were conducted as appropriate. Eleven articles (eight RCTs) were included, with two having high risk of bias. These RCTs were divided into three groups according to control cohort interventions: IPD implantation was compared with nonoperative treatment (group 1, n = 3), laminectomy (group 2, n = 3), and laminectomy associated with instrumented spinal fusion (group 3, n=2). Group 1 studies reported better Zurich Claudication Questionnaire (ZCQ) scores for the IPD group. In group 2, two studies reported comparable ZCQ scores and one revealed comparable visual analog scale (VAS) and Oswestry Disability Index (ODI) scores; pooled analysis showed a higher reoperation rate in patients treated with IPD. In group 3, one study found that more patients in IPD group gained more than 25 % improvement in VAS and ODI, with lower complication rate; the other reported better ZCQ scores in the IPD group and comparable complication and reoperation rates. IPD implantation is more effective than the other methods, but not superior to laminectomy in treating NIC.