Disk removal

Disk removal is one of the most common types of back surgery. Diskectomy (also called discectomy) is the removal of an intervertebral disk, the flexible plate that connects any two adjacent vertebrae in the spine. Intervertebral disks act as shock absorbers, protecting the brain and spinal cord from the impact produced by the body's movements.

Purpose

Removing the invertebral disk is performed after completion of unsuccessful conservative treatment for back pain that has been present for at least six weeks. Surgery is also performed if there is pressure on the lumbosacral nerve roots that causes weakness, bowel dysfunction, or bladder dysfunction.

As a person ages, the disks between vertebrae degenerate and dry out, and tears form in the fibers holding them in place. Eventually, the disk can develop a blister-like bulge, compressing nerves in the spine and causing pain. This is called a "prolapsed" (or herniated) disk. If such a disk presses on a nerve root and causes muscle weakness, or problems with the bladder or bowel, immediate disk removal surgery may be needed.

The goal of the surgery is to relieve all pressure on nerve roots by removing the pulpy material from the disk, or the entire disk. If it is necessary to remove material from several nearby vertebrae, the spine may become unsteady. In this case, the surgeon will perform a spinal fusion, removing all disks between two or more vertebrae, and roughening the bones so that the vertebrae heal together. Bone strips taken from the patient's leg or hip may be used to help hold the vertebrae together. Spinal fusion decreases pain, but decreases spinal mobility.

Description

The surgery is performed under general anesthesia. The surgeon cuts an opening into the vertebral canal, and moves the dura and the bundle of nerves called the "cauda equina" (horse's tail) aside, which exposes the disk. If a portion of the disk has moved out from between the vertebrae and into the nerve canal, it is simply removed. If the disk itself has become fragmented and partially displaced, or is not fragmented but bulges extensively, the surgeon removes the damaged part of the disk and the part that lies in the space between the vertebrae.

There are minimally invasive surgical techniques for disk removal, including microdiskectomy. In this procedure, the surgeon uses a magnifying instrument or special microscope to view the disk. Magnification makes it possible to remove a herniated disk with a smaller incision, causing less damage to nearby tissue. Video-assisted arthroscopic microdiskectomy has exhibited good results with less use of narcotics and a shortened period of disability. Newer forms of diskectomy are still in the research stage, and are not yet widely available. These include laser diskectomy and automated percutaneous diskectomy.

Total disk replacement research in the United States is underway. Products under investigation include the ProDisc (made by Spine Solutions, Inc.), and the SB Charite III (made by Link Spine Group, Inc.). In these clinical studies, a significant number of patients who received artificial disk implants report a reduction in back and leg pain; 92.7% state they are satisfied or extremely satisfied with the procedure.

Risks

All surgery carries some risk due to heart and lung problems or the anesthesia itself, but this risk is generally very small. (The risk of death from general anesthesia for all types of surgery, for example, is only approximately one in 1,600 surgeries.)

The most common risk of the surgery is infection, which occurs in 1–2% of cases. Rarely, the surgery damages nerves in the lower back or major blood vessels in front of the disk. Occasionally, there may be some residual paralysis of a leg or bladder muscle after surgery, but this is the result of the disk problem that necessitated the surgery, not the operation itself.