<p><b>OBJECTIVE</b>To study indications and complications of interspinous process device Coflex for degenerative disk diseases.</p><p><b>METHODS</b>One hundred and eight patients with degenerative lumbar disc diseases were underwent procedures of surgical decompression and additional fixation of Coflex between November 2007 and October 2010. Sixty-eight patients were male and the other fourty were female, and their average age was 53.5 years (range from 37 to 75 years). Fifty-nine patients were underwent surgery of excision of nucleus pulposus and Coflex fixation, 41 patients were underwent surgery of decompression by fenestration and Coflex fixation, 6 patients were underwent surgery of topping-off, and 2 patients were underwent surgery of Coflex fixation for two level. Preoperative and postoperative visual analogue scales (VAS) and Oswestry disability index (ODI) were recorded, as well as height of ventral intervertebral space (HV), height of dorsal intervertebral space (HD), height of intervertebral foramen (HIF) and segmental range of motion (ROM). One-way ANOVA was used for statistical analysis. Surgical complications were also recorded.</p><p><b>RESULTS</b>The average follow-up time was 28.8 months. All groups had apparent improvement of VAS and ODI, and maintained well to last follow-up (F = 6.16-25.92, P = 0.00). Statistical analysis showed that HD and HIF increased significantly in group with excision of nucleus pulposus and Coflex fixation and group with decompression by fenestration and Coflex fixation (F = 7.37 - 11.68, P < 0.05). Although both HD and HIF decreased one-year after surgery, they were still higher than those preoperatively (F = 6.31 and 7.05, P = 0.00). Preoperative segmental ROM was respectively 6.3° ± 1.8° and 6.2° ± 1.7° in group with excision of nucleus pulposus and Coflex fixation and group with decompression by fenestration and Coflex fixation, and 3.1° ± 0.6° and 3.0° ± 0.8° at last follow-up. Three cases were found with device-related complications and five with non-device-related complications, and all five cased were cured after appropriate treatment.</p><p><b>CONCLUSIONS</b>Surgical method assisted with Coflex has significant clinical efficacy for degenerative disc disease, it can maintain segmental stability, simultaneously, partly reserve movement. It's key to strictly master indications and precisely choose patients.</p>