Transforaminal Selective Endoscopic Discectomy: Extremely Minimally Invasive Surgical Treatment for Low Back and Leg Pain
Ninety-five percent (95%) of people who sustain a low back injury will recover with non-surgical treatments and preventive measures. However, a small number of patients (<5 %) will not respond to non-surgical interventions.
The purpose of this article is to introduce Selective Endoscopic Discectomy (SED). SED is an alternate treatment procedure for some chronic pain patients who wish to avoid extensive spine surgery and general anesthesia.
The patient sustained a low back (lumbar) injury and has no previous history of back problems. The patient was seen by a general practitioner, chiropractor, or emergency room physician. Initial treatment may have included anti-inflammatory medication, muscle relaxants, analgesics, physical therapy, and reduced physical activity. Several months have passed without significant symptom resolution.
Further workup by a spine specialist (e.g. orthopedic surgeon, neurosurgeon) included an MRI study that may have revealed one or more disc bulges, disc protrusions, or herniated discs. The new treatment plan included bracing, a series of epidural corticosteroid injections, and a course of physical therapy with trunk and low back stabilization exercise.
Figure 1. Examples of Disc Problems
The patient noticed some symptom improvement with the above treatments, but continues to have low back pain that radiates into one or both legs (radicular pain). Several months have passed since non-surgical treatments were initiated. Since these treatments have not adequately resolved the patient's symptoms, the spine specialist (physician) discusses surgical options (e.g. laminectomy, discectomy). The physician explains that any type of spine surgery has risks, including the risks separately associated with anesthesia.
To determine if the patient is a candidate for SED, the physician reviews the patient's history, performs a physical and neurological examination, and reviews the lumbar MRI studies. If the patient is found to have a contained disc protrusion, herniated disc, or discitis unassociated with severe arthritic changes (i.e. bone spurs), the patient would be recommended for a provocative discogram. A provocative discogram helps to confirm which disc(s) is(are) causing pain. If the discogram is positive, the SED procedure would follow.
A provocative discogram is a diagnostic test study of one or more intervertebral discs performed under fluoroscopic guidance. The procedure may be performed at an outpatient surgical center under local anesthesia. In order to talk to the physician during the test, the patient remains awake.
The patient is positioned on the table face down and a local anesthetic is administered. A special type of needle is inserted into the center of the abnormal and adjoining discs. A solution of contrast dye mixed with indigo carmine blue dye is injected into each disc.
As the dye is injected into the center of each disc, the pressure created is intended to reproduce the patient's symptoms; low back and leg pain. The dye further serves to define the damaged disc's abnormal anatomy. The entire procedure is guided and viewed using fluoroscopy.
If the patient's symptoms are reproduced during the discogram, the test is considered a positive concordant discogram. The patient can then be treated using SED immediately following the discogram or at a later time.
Surgical Procedure: Selective Endoscopic Discectomy (SED)
The patient is positioned on the operating room table prone (face down) padded by special pillows. The patient will remain awake during the procedure. After a local anesthetic is administered, a small needle is inserted into the disc space. A 7mm (1/4-inch) skin incision is made and a slightly larger probe is slipped over the needle into the abnormal disc.
Using x-ray and fluoroscopic guidance, micro-instruments (e.g. mini forceps, curettes, cutters), Ellman radiofrequency device, Endius shaver, and a laser probe are used to remove only the damaged disc. The laser is used to further remove and shrink the disc (disc decompression) and to tighten the annulus. The patient's exposure to x-ray is minimal. On average, the procedure takes about 30 minutes to one-hour per disc.
The amount of disc removed and shrunk by means of the laser varies and only includes the herniated and damaged portions. The supporting structure of the disc is not affected. Upon completion of the SED, the probe is removed and a small bandage is applied over the needle incision.
Figure 2. Used with Permission. Anthony T. Yeung, M.D.
Illustration by David Azarello and Christopher Yeung