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Related to chemonucleolysis: discectomy, laminectomy




Chemonucleolysis is a medical procedure that involves the dissolving of the gelatinous cushioning material in an intervertebral disk by the injection of an enzyme such as chymopapain.


Between each vertebra lies a disk of cushioning material that keeps the spinal bones from rubbing together and absorbs some of the shock to the spine from body movements. In the center of the disk is soft, gelatinous material called the nucleus pulposus (NP). The NP is surrounded by a tough fibrous coating. Sometimes when the back is injured, this coating can weaken and bulge or tear to allow the NP to ooze out. When this happens, it is called a herniated nucleus pulposus (HNP), or—in common language—a herniated disk.
When the disk bulges or herniates, it can put pressure on nerves which originate in the spinal column, and go to other parts of the body. This causes lower back pain, and/or pain to the hips, legs, arms, shoulders, and neck, depending on the location of the herniated disk. Chemonucleolysis uses chymopapain, an enzyme derived from papyrus, to dissolve the disk material that has been displaced because of injury. Herniated disks are the cause of only a small proportion of cases of lower back pain, and chemonucleolysis is appropriate for only some cases of HNP.
Chemonucleolysis is a conservative alternative to disk surgery. There are three types of disk injuries. A protruded disk is one that is intact but bulging. In an extruded disk, the fibrous wrapper has torn and the NP has oozed out, but is still connected to the disk. In a sequestered disk, a fragment of the NP has broken loose from the disk and is free in the spinal canal. Chemonucleolysis is effective on protruded and extruded disks, but not on sequestered disk injuries. In the United States, chymopapain chemonucleolysis is approved only for use in the lumbar (lower) spine. In other countries, it has also been used successfully to treat cervical (upper spine) hernias.
Other indications that a patient is a good candidate for chemonucleolysis instead of surgery include:
  • the patient is 18-50 years of age
  • leg pain is worse than lower back pain
  • other conservative treatments have failed
  • The spot where the herniated disk presses on the nerve has been pinpointed by myelography, computed tomography scan (CT scan), or magnetic resonance imaging (MRI)
  • the patient wishes to avoid surgery


There are some situations in which chemonucleolysis should not be performed. Chymopapain is derived from the papaya. About 0.3% of patients are allergic to chymopapain and go into life-threatening shock when exposed to the enzyme. Chemonucleolysis should not be performed on patients allergic to chymopapain or papaya. It also should not be done:
  • when the patient is pregnant
  • if the disk is sequestered
  • if the patient has had several failed back operations
  • if a spinal cord tumor is present
  • if the patient has a neurological disease such as multiple sclerosis
Other conditions may affect the appropriateness of chemonucleolysis, including hypertension, obesity, diabetes, and a family history of stroke.


A small gauge needle is placed in the center of the affected disk. Chymopapain is introduced into the disk. The patient needs to remain still.


Patients will need tests such as a myelogram or CT scan to pinpoint the herniated disk. Some doctors medicate the patient 24 hours prior to the operation in order to decrease the chances of post-operative lower back stiffness.


Patients may feel lower back stiffness, which goes away in few weeks. Heavy lifting and sports activities should be avoided for at least three months.


The greatest risk is that the patient may be allergic to chymopapain. The death rate for chemonucleolysis is only 0.02%. Complications overall are five to 10 times less than with conventional surgery, and the failure rate is roughly comparable to the failure rate in conventional disk surgery.

Normal results

Many patients feel immediate relief from pain, but, in about 30% of patients, maximal relief takes six weeks. The long term (seven to 20 years) success rate averages about 75%, which is comparable to the success rate for conventional surgery.



Alexander, Herbert. "Chemonucleolysis for Lumbar Disc Herniation: How Does it Stack up to Other Minimally Invasive Approaches?" Journal of Musculoskelatal Medicine 12, no. 2 (1995): 13-24.

Key terms

Chymopapain — An enzyme from the milky white fluid of the papaya, used for medical purposes in chemonucleolysis.
Myelography — An x-ray test that evaluates the subarachnoid space of the spine.
Nucleus pulposus (NP) — an elastic, pulpy mass in the center of each vertebral disk.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


dissolution of a portion of the nucleus pulposus of an intervertebral disk by injection of a chemolytic agent such as chymopapain for treatment of a herniated intervertebral disk.
Patient Care. The most serious complication of chemonucleolysis is anaphylaxis. Contraindications include any bowel or bladder dysfunction, pregnancy, and a history of previous treatment with chymopapain, which could increase the possibility of an allergic reaction. Any of these conditions identified during preoperative assessment should be reported to the surgeon immediately.

Postoperatively the patient is monitored for signs of anaphylaxis, alteration in neurological status, and discomfort or pain due to muscle spasm.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Rarely used technique involving injection of chymopapain into the nucleus pulposus of an intervertebral disc as a therapeutic option for the treatment of a herniated nucleus pulposis (for example, slipped disk).
Farlex Partner Medical Dictionary © Farlex 2012


Neurosurgery The injection of an enzyme–eg, chymopapain, as an alternative to laminectomy in certain cases of intervertebral disc rupture. See Laminectomy.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


Injection of chymopapain (an enzyme) into the herniated nucleus pulposus of an intervertebral disc.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


The use of an enzyme injected into the inner pulpy centre of an intervertebral disc so as to break down and liquefy the material. This is done as a treatment for ‘slipped disc’ (prolapsed intervertebral disc) with pressure on the nerve roots in the spinal canal.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Chemonucleolysis versus open discectomy: the case against chymopapain.
It was only in 1964 that chemonucleolysis was reported as an alternative surgical treatment, when Smith injected chymopapain directly into the intervertebral disc of human subjects.
Chemonucleolysis hydrolyzes the noncollagenous proteins of the disc to depolymerize the nucleus pulposus, liberating chondroitin sulfate and keratin sulfate elements, thereby altering the characteristic integrity of the nucleus pulposus.
Incidence and risk factors for latent sensitization to chymopapain: predictive skin-prick tests in 700 candidates for chemonucleolysis. Clin Exp Allergy 1994; 24:471-476.
* Past surgical history: Chemonucleolysis L4-L5 and right knee surgery, remote.
A The treatment you are referring to is known as chemonucleolysis. An enzyme injected into the problem disc dissolves the slipping soft centre, but leaves the outer shell intact.
(1986) Chemonucleolysis versus surgical discectomy: Comparison of costs and results in workers' compensation claimants.
A guest editorial in the same issue points out that consumers ingest increasing amounts of papain in fast-food products, and approximately 100,000 chemonucleolysis procedures are performed in the United States each year.
But about 1 percent of chemonucleolysis patients exhibit anaphylactic (allergic) reactions, and some individual allergy clinit patients show positive test results for both enzymes.
(7) Various surgical modalities are available for management of intervertebral disc prolapsed, Prolapsed lumbar disc excision, Chemonucleolysis, Percutaneous Disc Surgery Arthroscopic Discectomy, Percutaneous Laser Discectomy, Micro-discectomy/Posterior limited discectomy.
However with advancement of technology, minimally invasive Image guided interventional techniques were introduced which included intradiscal steroids, chemonucleolysis, disc decompression, annuloplasty and various procedures using intradiscal laser device application.
CHEMONUCLEOLYSIS: With derivation of chymopapain enzyme from papaya fruit in 1940, experiments to use it for scientific benefit were conducted in 1963, Smith et al (1) used its dehydrating effect in treatment of discogenic pain-Injecting the drug into the nucleus pulposus of the painful bulging disc caused the disc to lose its turgidity and shrink as a result of depolymerization of the proteoglycan and glycoprotein molecules in the nucleus pulposus--this 'shrinking effect' causes the disc to reduce in its height and girth, relieving pressure on the traversing neural component-the source of pain.