Application of the Coflex Interlaminar Stabilization in Patients With L5/S1 Degenerative Diseases: Minimum 4-Year Follow-up

The Coflex is one of the representatives of posterior dynamic interspinous process device, but no study with the application of Coflex interlaminar stabilization in L5/S1 level has been performed. The aim of this study was to evaluate the feasibility and validity of the Coflex interlaminar stabilization in the treatment of degenerative lumbar diseases on L5/S1 level. A retrospective study was conducted for a consecutive series of 33 patients with degenerative lumbar spinal stenosis or lumbar disc herniation located in L5/S1 between November 2007 and September 2010. Subjects were all received decompressive laminectomy with implantation of Coflex device. Clinical effects were evaluated by visual analog scale and Oswestry Disability Index. Radiographs were done preoperatively, postoperatively, and at final follow-up. The Coflex devices were successfully implanted in all subjects. Fourteen cases completed the operations by inverting the prosthesis on account of too short S1 spinous processes. During the minimum 4-year follow-up period, all patients had obvious improvement in clinical effects (P < 0.05). Radiological evaluation revealed that dorsal intervertebral space height and intervertebral foramen height of target level increased significantly in all cases postoperatively and maintained well to final follow-up. In addition, the sagittal range of motion of operated level was restricted (P < 0.05), and the range of motion of adjacent segment did not change much (P > 0.05). The Coflex is an efficacious dynamic interspinous process device for the treatment of degenerative lumbar diseases that can apply to L5/S1.