Interspinous Process Spacers

The spinous processes are located in the very back of the spinal column near the skin surface.  They are palpable on your own body by taking your hand to the center of your back throughout its course you can feel sharp prominences in the midline that are the spinous processes.  The near proximity of the spinous processes to the skin allows for the implantation of interspinous process spacers with minimal operative intervention and spinal morbidity (unwanted aftereffects of the surgery).

The interspinous process devices are designed to distract (open) the foramen, where the nerve endings pass away from the center of the spinal region and into the legs. It is thought that these devices may also unload the intervertebral disc. They may limit spinal extension (the position the spine takes on when bending backward). This backward bending position may be painful for patients with spinal stenosis because it reduces the space available for the nerve roots in the exiting foraminal openings.

The interspinous devices may be implanted with the patient under a mild sedative and local anesthesia as a day surgery procedure (patient goes home the same day) or under light anesthesia. This may be beneficial for elderly patients for whom more extensive open surgery may present too great of a surgical risk due to less favorable general health and fitness level. Interspinous process spacers have however lost their initial popularity amongst many spine surgeons as they have been found to have a high revision rate.  Instead of directly addressing the pathology behind the spinal stenosis causing either the radiculopathy or neurogenic claudication (leg pain) that the patient is experiencing, the interspinous process spacers indirectly decompress the canal.  Certain patients who do not get great relief from this procedure will end needing a traditional, open procedure, and in others, the device migrates as it is not usually secured into place, merely fit depending on the manufacturer.