Minimally Invasive Procedures

Percutaneous interspinous spacer placement

Interspinous spacers are medical devices that have recently been developed for the treatment of spinal stenosis. In spinal stenosis, there is a narrowing of the spine which worsens with standing and walking, causing pain to the buttocks or legs. Interspinous spacer placement is a minimally invasive surgical procedure. That means that interspinous spacers are less invasive than open surgical procedures traditionally performed for the same purpose. Interspinous spacers also belong to a family of spine surgical procedures called dynamic stabilization. Dynamic stabilization means that these devices are placed in the spine to relieve a condition while maintaining or restoring the natural mobility of the spinal segment.

Interspinous spacers are placed between two bony protuberances in the middle of the back. These bony protuberances can be easily felt in the middle of the back and are called spinous processes. The spacer allows the portion of the spine where the nerves travel to remain sufficiently open in patients suffering from spinal stenosis. Since these spaces narrow with standing and walking, activities that extend the spine, spinal stenosis patients usually have worsened symptoms with these activities. Conversely, since the nerve occupying spaces open with sitting and bending, activities that flex the spine, spinal stenosis patients have improved symptoms and relief with these activities. Placing the spacer between the spinous processes maintains the relief that patients have with flexion, even during standing and walking.

There are two methods for inserting an interspinous spacer. In one method, an incision is made in the back and the spinous processes are exposed. Under direct visualization, the interspinous spacer is inserted. The deep tissues and skin are then closed with sutures. In the percutaneous method, a small skin incision is made in between the spinous processes. A metal tube is then placed in the middle of the back between the spinous processes. Through this tube the spacer is inserted and fixed in position by opposing it against the spinous processes. The small skin incision is then closed with several superficial sutures.