Clinical Symposium II: Interspinous-based Dynamic Stabilization

Abstract

Introduction

Interspinous-based dynamic stabilization has become a popular form of treatment in recent years. Though many companies have developed innovative designs for interspinous spacer devices, there are many questions yet to be answered. Some of these devices have considerably more clinical experience than others, but their role in the treatment of spinal pathologies is still controversial.

The mechanism of action in itself has not been fully elucidated, though many theories have been proposed. Validation of these theories becomes important to determining the appropriate indications for use of these devices. Without a clear understanding of the mechanism of action or what these implants really do, their future would remain questionable. The general consensus seems to be that these devices help by unloading the facet joints and thereby have a role to play in treating back pain arising from facet arthrosis. Others have used a spacer device to indirectly decompress the spinal canal in spinal stenosis. The effect on the disc itself is still largely undetermined.

The stability provided by these devices is also unknown and has led to some innovative designs including tethers that bind the device to the spinous processes. Wings and flanges have been designed to keep the device in place and the importance of maintaining the interspinous ligament post implantation is indeed unknown.

Although only one spacer has been FDA-approved for use in the US, we now have several years of follow-up data on hundreds of patients from well-designed IDE studies of multiple devices. Other devices have received the CE mark in Europe. Changes have been made to designs and materials in several spacer devices.

To help us better understand the mechanisms and design challenges of some of these devices and to get a fresh update on the results of ongoing testing, we went to 3 esteemed surgeons who have been instrumental in the development, refinement, and testing of 3 of the interspinous spacers: Coflex, Diam, and X-Stop. Their insight into this technology is presented in this symposium for our readers.