Posterior dynamic stabilization
L Sak
Citation
L Sak. Posterior dynamic stabilization. The Internet Journal of Minimally Invasive Spinal Technology. 2008 Volume 3 Number 4.
Abstract
One of the most rapidly evolving fields in spinal surgery is PDS. This new category of thoracolumbar spinal surgery focuses on the concept of maintaining or restoring intervertebral motion in a controlled fashion, whether by restricting the extremes of spinal movement or by dampening the kinetic energy involved in motion. The goal of these implantable devices is to mimic the behavior of the healthy spinal column (Fig. 1). Since the mid-1980s, a number of PDS devices have been introduced in the market. P. Khoueir (2007) have classified them into three main categories: 1) posterior interspinous devices; 2) pedicle based dynamic rod devices; and 3) total facet replacement systems.The coflex interspinous implant was invented by Dr. Jacques Samani in 1994 and has been in continuous use since 1995 outside the United States. Initially, the product was known as the Interspinous “U” and was marketed by Fixano SAS (Peronnas, France). Transfer of ownership to Paradigm Spine was finalized in early 2005, and the product was renamed “coflex interspinous implant”. The design and materials were not changed, but two new sizes were added. The only differences between the Interspinous “U” and the coflex interspinous implant are the manufacturing technique and the tightening of tolerances. Materials and methods: Dynamic interspinous fixation was performed in 102 patients at the age of 21 to 72 years. Mean follow-up was 1 year 8 months. 87 patients underwent surgery for the first time and 15 had recurrent herniated disc. The total number of implants used on the 102 patients was 107. Implant sites were as follows: L2-L3 – 2, L3- -L4 – 8, L4-L5 – 80, L5-S1 – 12; 97 patients were operated at one level and 5 - at two levels.Indications:· degenerative lumbar spinal stenosis - 37 patients;· isolated herniated disk - 33 patients;· lumbar spinal stenosis with herniated intervertebral disc – 14 patients;· herniated disc + vertebral instability - 3 patients;· recurrent herniated disc - 15 patientsThe implanting technique is simple. Using a conventional median approach, the spinous processes are sparingly resected either side of the ligamentum flavum; endocanal procedure is performed: decompression, release of the foramen, possible curettage of herniated intervertebral disc. The size is chosen using templates. Coflex is then inserted. The clips are tightened around the spinous processes. Results: Mean values of the Oswestry Disability Index and VAS in patients examined at 6, 9 and 12 month postoperatively decreased up to the level of minimal lesion. We had no late neurological complications related to the “Coflex”, and no cases of the device penetration inside the canal. Radiological signs of bone tissue resorption in bone-implant interface were not observed.Conclusion: The major indication is a single “Coflex” positioned at L4-L5 to treat lumbar spinal stenosis, large and recurrent disc herniation.