Lumbar Discectomy: Minimally Invasive Spine Surgery
Micro Endoscopic Discectomy (MED)
This article focuses on microdiscectomysurgery. To learn more about traditional (open) discectomy surgery, please read our article on percutaneous discectomy.
A patient is brought into the operating room and is put under general anesthesia. Some surgeons have chosen to perform microdiscectomy under local or spinal anesthesia, allowing the patient to stay awake throughout the procedure. The patient is turned onto his abdomen and padded into position. A fluoroscope (floor-o-scope, a machine which projects live x-ray pictures onto a screen) is brought in for use during the remainder of the operation. The patient's back is scrubbed with sterile soap, and a sterile field is created. Drapes are placed accordingly, and the surgery begins. See Figures 1, 2, 3, 4.
Figure 1: Operating Room. An example how the operating room is setup for a lumbar microdiscectomy. The surgeon stands on the side of the ruptured disc. The television monitor is across the table. For the majority of the operation, the surgeon performs the surgery while watching it on the screen. Copyright Medtronic Sofamor Danek. Used by Permission.
The disc space is confirmed using the fluoroscope, and a long acting, local anesthetic is injected through the muscle and around the bone protecting the disc. A half to one-inch incision is made. A thin wire is placed through the incision and lowered until it touches the bone. Progressively larger dilators are brought down on top of one another following the wire. In this manner, the muscle is split rather than separated from the bone.
Figure 2: Endoscope. A representation of the working channel once the serial dilators have been removed and the endoscope is placed. Copyright Medtronic Sofamor Danek. Used by Permission.
When a small amount of muscle is left over the lamina (lamb-in-ah), or exposed bone, this is cleaned off. In order to access the nerve, this roof of bone must be removed; this can be done with a small, high-speed drill or a small bone-biting tool called a Kerrison rongeur. The bone just below the endoscope covers the nerve, as it is about to exit the spine. By removing the bony cover, the nerve can be exposed and then safely moved away.
Figure 3: Lamina. A representation of the area of lamina that needs to be removed to visualize the nerve and the disc rupture. Copyright Medtronic Sofamor Danek. Used by Permission .
Figure 4: Lamina Removal. A representation of the intraoperative area and the Kerrison rongeur removing the superior lamina. Copyright Medtronic Sofamor Danek. Used by Permission.
This article is based on an excerpt from Dr. Stewart G. Eidelson's book, Advanced Technologies to Treat Neck and Back Pain, A Patient's Guide (March 2005).