Last Updated on October 9, 2023
Chemonucleolysis is the term used for the chemical destruction of the nucleus pulposus [Chemo+nucleo+lysis]. This involves the intradiscal injection of chymopapain or other agents which causes hydrolysis of the cementing protein of the nucleus pulposus. This causes a decrease in water binding capacity leading to a reduction in size and drying the disc.
Chemonucleolysis is one of the methods to treat disc herniation not responding to conservative therapy.
Lumbar disc herniation and cervical disc herniation are common causes of back pain and neck pain. While the majority of the patients improve with conservative measures like rest, drugs, and physical therapy, surgical options including minimally invasive procedures need to be considered in some.
Chemonucleolysis is one of the minimally invasive procedures. It consists of the intradiscal injection of chemonucleolytic substances that cause dehydration of the disc matrix. This results in the reduction of the intradiscal pressure and volume leading to a reduction in the size of the disc and thus nerve decompression.
Chemonucleolytic Materials used for Chemonucleolysis
- Chymopapain
- Collagenase
- Oxygen-ozone mixture
- Discogel – a radio-opaque jellified ethanol
- Chondroitin sulfate ABC endolyase,
- Matrix metalloproteinase
Cymopapain was the first agent to be used.
Oxygen-ozone mixture and Discogel are more commonly used at this time.
Basis of Chemonucleolysis
Nucleus Pulposus is a soft, gelatinous material in the center of the disc and is surrounded by a tough fibrous coating annulus fibrosus. In disc herniation, weakened or torn annulus fibrosus allows the nucleus pulposus to ooze out
Chemonucleolysis uses materials to dissolve the disc material and decompress the neural structures.
Collagenase acts to lyse the collagen and shrink the protrusion thus releasing the mechanical pressure on the nerve.
Ozone gas possesses antiseptic and anti-inflammatory properties. it decompresses the disc and releases mechanical pressure.
Chondroitin sulfate ABC endolyase is an enzyme that catalyzes the depolymerization of chondroitin sulfate, which is present in the nucleus pulposus. This enzyme is obtained from Proteus vulgaris.
Chemonucleolysis is not effective in sequestered discs. In sequestered discs, a fragment of the nucleus pulposus breaks loose from the disk and is free in the spinal canal.
Indications
- Age between 18-50 years of age
- Leg pain is worse than lower back pain
- Failure of conservative treatment
- Compression of neural structures by the herniated disc
Contraindications
- Allergy to substance that is going to be used
- Pregnancy
- Sequestered disc
- Failed back surgery syndrome
- The presence of neurological diseases such as multiple sclerosis
How Chemonucleolysis is Done?
It is of utmost importance to establish the intended level of disc to be responsible for the pain. Discography and CT Myelogram are often used for confirmation.
The patient might be admitted a day prior to the procedure or the procedure can be done on an outpatient basis.
General or local anesthesia may be used. Intravenous access should be present before the procedure is carried out.
The patient is taken in the left lateral decubitus position and the disc is reached using a 22-gauge spinal needle with a stylet. The position of the needle tip is confirmed under fluoroscopy and under fluoroscopic guidance the needle is advanced to the center of the nucleus pulposus.
The stylet is pulled out and the substance for nucleolysis is injected in the specified quantity for the substance. The needle is withdrawn.
Recovery can take 6-12 weeks and pain relief may not be there initially or is partial. Therefore, pain relief drugs may be prescribed.
Following the treatment patients may feel lower back stiffness, which goes away in a few weeks. Heavy lifting and sports activities should be avoided for three months.
Risks and Complications
- Allergies (most common)
- Infections (rare)
- Intrathecal injections lead to bleeding.
Outcome
Many patients feel immediate relief from pain, but, in about 30% of patients, maximal relief takes six weeks. The long-term success rate averages are comparable to the success rate for conventional surgery. But similar results are also achieved by conservative treatment.
Chemonucleolysis is the subject of controversy and some surgeons consider surgery to be a better choice than chemonucleosis. Newer available agents have renewed interest in this procedure.
References
- Couto JM, Castilho EA, Menezes PR. Chemonucleolysis in lumbar disc herniation: a meta-analysis. Clinics (Sao Paulo). 2007 Apr;62(2):175-80. [link]
- Ishibashi K, Iwai H, Koga H. Chemonucleolysis with chondroitin sulfate ABC endolyase as a novel minimally invasive treatment for patients with lumbar intervertebral disc herniation. J Spine Surg. 2019 Jun;5(Suppl 1):S115-S121. [Link]
- Ishibashi K, Iwai H, Koga H. Chemonucleolysis with chondroitin sulfate ABC endolyase as a novel minimally invasive treatment for patients with lumbar intervertebral disc herniation. J Spine Surg. 2019 Jun;5(Suppl 1):S115-S121. [Link]
