Chemonucleolysis for herniated disc

Treatment Overview

Chemonucleolysis is the injection of an enzyme into a bulging spinal disc, with the goal of reducing the disc's size. This procedure is performed in a hospital or surgical center as an outpatient procedure.

Prior to chemonucleolysis, your doctor checks to see whether a herniated disc is causing your symptoms by using an imaging study, such as computerized tomography (CT scan) or magnetic resonance imaging (MRI). During this procedure, a dye may first be injected to determine whether the disc has completely ruptured or is bulging (discography).

If the disc is bulging and has not broken open (ruptured), chemonucleolysis can be considered as a treatment option.

Chemonucleolysis uses an enzyme called chymopapain (derived from papaya), which is injected into the disc space. Local anesthesia or general anesthesia may be used to control pain during the injection. Chymopapain speeds up the breakdown of the jellylike substance inside the disc (nucleus), releasing water. As a result, the bulging disc may shrink and relieve pressure on the nerve root.

Although it is widely used in Europe, this procedure is rarely done in the United States and is no longer done in Canada because many health professionals feel it is less effective than surgical treatments.

What To Expect After Treatment

After chemonucleolysis, you may have moderate to severe back pain and spasms lasting from 2 to 3 days or longer after the procedure. You can use prescription medications to control pain during the recovery period.

For at least 6 weeks, avoid long periods of sitting and repetitive bending, stooping, and lifting.

Depending upon your individual condition and work requirements, it may take weeks or months for you to return to your normal activities.

Why It Is Done

Although it is widely used in Europe, this procedure is rarely done in the United States and is no longer done in Canada, based on concern about the risk of serious side effects (particularly a potentially life-threatening allergic reaction).¹ In addition, not all doctors agree that it is effective.

This procedure may be done when the following conditions are met:

• Your history, physical examination, and diagnostic imaging (CT scan, MRI) indicate that the disc is bulging, but the material inside the disc (nucleus) has not ruptured into the spinal canal.
• Pain and nerve damage have not improved after at least 4 weeks of nonsurgical treatment.
• Your symptoms are severe and disabling.
• You are not able or willing to have surgery.

Sometimes chemonucleolysis is done when there are signs of serious nerve damage (that may be getting worse) in the leg. These can include severe weakness, loss of coordination, or loss of feeling. But most doctors would be more likely to do surgery to remove the disc (discectomy) if symptoms are this severe.

How Well It Works

Research indicates that chemonucleolysis can be an effective treatment for carefully selected herniated disc problems. But it is less effective than standard discectomy and may lead to a need for further treatment, which may include surgery.²

Risks

Risks of this surgery include:

• An allergic reaction to the enzyme or the dye used to see the disc. This can range from a simple rash with itching and localized swelling to a life-threatening reaction that leads to difficult breathing and shock (anaphylaxis). (These reactions are now rare since doctors began testing patients for allergic reactions by using a simple skin test.)
• Increased back pain and muscle spasms after the injection.
• Severe back pain that may limit daily activities for up to 3 months after treatment for many people.

What To Think About

Discectomy (or microdiscectomy) is more effective than chemonucleolysis and has fewer potential side effects.²

Complete the special treatment information form (PDF) (What is a PDF document?) to help you understand this treatment.

Author:	Shannon Erstad, MBA/MPH	Last Updated August 9, 2006
Medical Review:	William M. Green, MD - Emergency Medicine Robert B. Keller, MD - Orthopedics
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