An endoscopic dural retractor for spinal stenosis surgery

Adequate neural decompression is the goal of lumbar stenosis surgery. Often because of limited visualization of the nerve root, significant portions of the facet joints are removed for decompression enhancing the potential for the development of instability. Clearly, the goal to better visualize the anatomy of the lateral recess while decompressing the nerve root may result in better root decompression and a smaller potential for instability secondary to bone loss. In order to accomplish this goal we have designed an endoscopic dural retractor that while retracting the dura permits simultaneous visualization of the anatomy of the lateral recess and the activity of instruments used to decompress it. The endoscopic dural retractor contains a 10000 pixel endoscope that allows a direct lateral view into the lateral recess while the dura is being retracted. This is a view that cannot be achieved with the operating microscope. One can easily appreciate the anatomy of the lateral recess including the facet joint, ligamentum flavum, lateral dura and nerve root. Ten geriatric cadaver lateral recesses were decompressed endoscopically using the endoscopic retractor. Compression of the nerve root by the facet and ligamentum could easily be identified. One could visually monitor the use of instruments on removal of ligamentum flava and bone compressing the nerve root. In all cases the ligament was easily removed and the facet joint was undercut only enough to decompress the nerve. This instrument has the potential for less invasive decompression of spinal stenosis and further study of its utility is planned.