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1. Percutaneous Discectomy Devices
2. Conclusion

Back pain related to a herniated intervertebral disc is one of the most common causes of chronic disability. Although many cases of acute low back pain will resolve with conservative therapy, a surgical decompression is often considered when the pain is unresolved after conservative therapy. Historically, open surgery has been used to treat radicular pain, by either discectomy; e.g. removing part of the abnormal intervertebral disc or by decompressive laminectomy; e.g. resecting portions of the lamina to relieve the pressure on the spinal canal and nerve roots. Surgical success rates have been in excess of 90%. Decompressive surgical techniques have advanced to the point where procedures utilizing laser or radiofrequency energy are performed through smaller incisions or via endoscopy.

Percutaneous disc decompression has been used in the treatment of herniated discs for over 40 years and in over 500,000 patients. A variety of techniques have been used to decompress discs, including chemical, mechanical and thermal/heat (radiofrequency and laser) methods. Early procedures showed conclusively that percutaneous disc decompression effectively relieves pain for appropriate patients. Intradiscal electrothermal anuloplasty (IDET) is another minimally invasive approach to low back pain in which a heated element is used to treat pain thought to arise from the surrounding annulus. This procedure has met with limited clinical success.

The Stryker Dekompressor (Stryker) and Nucleoplasty (Arthrocare) are examples of FDA approved percutaneous discectomy devices. Percutaneous disc decompression has been shown to treat symptomatic patients with contained herniated discs. The ideal patient would meet the following common criteria for any of the techniques considered.

Inclusion criteria include: radicular symptoms; e.g. leg pain greater than back pain, CT or MRI evidence of contained posterior-lateral disc protrusion and failed epidural/selective nerve root block (included to ensure that patients are given the opportunity to respond to conservative care), failed conservative therapy for 3 months and discography positive for concordant pain.

Exclusion criteria include: disc height of less than 50%, evidence of severe disc degeneration, spinal fracture, spinal tumor or spinal stenosis.

Contraindications include: traumatic spinal fracture, infection, tumor, pregnancy and severe co-existing medical disease(s).

The procedure is not indicated for the treatment of pain originating from structures other than herniated discs. Patients with a free disc fragment, severe bony stenosis, severely degenerative discs or with severe and rapidly progressing neurological deficits are excluded.
Potential complications include: infection, bleeding, nerve damage, worsening of pain, paralysis, idiosyncratic reaction, anaphylaxis and death.

The procedure is performed under local anesthesia or conscious sedation to allow patient monitoring for signs of segmental spinal nerve irritation. No general anesthetic is required. Once the needle is inserted into the disc, the procedure itself takes only a few minutes. The entire procedure lasts less than one hour and the patient is able to leave shortly afterwards. There is typically little pain after the procedure and it is easily managed with analgesics. Patients are advised to avoid lifting and strenuous exercise and may go back to sedentary work after one week. Patients with more physically demanding occupations may need to wait longer to recommence their daily activities. Additional physical therapy may prove beneficial in the recovery period.

Percutaneous discectomy may result in a decrease in anesthesia time, procedure time and recovery time, a lower complication and morbidity rate and a significant reduction in post-operative spinal instability. Percutaneous discectomy has demonstrated the potential to produce equivalent, or even better, outcomes than conventional surgery in a procedure that is permanent, simpler, quicker, less traumatic with less perineural scarring and post-operative fibrosis and has faster recovery times. Clinical results are very promising and patients can generally expect rapid and sustained pain reduction.

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Percutaneous Discectomy Devices

DISC Nucleoplasty (Arthrocare) - www.nucleoplasty.com

DISC Nucleoplasty uses a unique plasma technology, called coblation, to remove tissue from the center of the nucleus pulposus. During the procedure, the DISC Nucleoplasty probe is introduced through a needle and placed into the center of the disc where a series of channels are created to remove tissue from the nucleus.

Access to the disc is made through a 17 gauge (cervical or thoracic) or 19 gauge (lumbar) cannula with an obturator stylet using an anterior-lateral approach in the cervical spine or a posterior-lateral approach in the thoracolumbar spine. While monitoring the patient, the probe is advanced into the disc. As it is advanced, the coblation plasma mode is activated and tissue along the path of the device is removed via molecular dissociation. Tissue is turned into gas, which exits the disc via the introducer cannula. After the first channel is created, the probe is rotated clockwise, and re-advanced creating another channel. Approximately six channels are made in total, depending on the desired amount of tissue reduction.

Since its first application in July 2000, the Nucleoplasty procedure has been used to treat over 35,000 patients worldwide. Initial outcome studies show high success rates. Average pain reduction is significant, 55-60%. Patient satisfaction is high, about 90%, largely due to the relative ease of the procedure, the lack of a painful rehabilitation period and the fact that the procedure does not preclude any subsequent procedure such as open surgery. Although long-term data is not yet available, the early studies show pain relief is sustained up to two years post-procedure.

The Dekompressor Percutaneous Lumbar Discectomy Probe (Stryker) www.dekompressor.com

The Dekompressor utilizes a self contained motorized drill for removal of nucleus pulposus through a small channel under fluoroscopic guidance. Superficial, deep and intradiscal anesthesia is provided with local anesthetics. The cannula is advanced into the disc space via a posterior-lateral approach into the intervertebral disc space. As the device is activated, the drill bit disrupts nuclear tissue and mechanically draws material to a collection chamber at the base of the motor assembly. Patients rarely experience any discomfort during the procedure. The Dekompressor is capable of aspirating disc material from the intervertebral disc space of the lumbar, thoracic and cervical spine.

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Conclusion

In conclusion, newer techniques in interventional pain offer the potential to significantly reduce the morbidity and mortality of major neurosurgical procedures of the spine.

Percutaneous discectomy, a new minimally invasive technique, may prove useful in relieving the pressure on spinal nerve roots by small herniated intervertebral discs. The procedure has demonstrated the potential to produce equivalent, or better, outcomes than conventional spinal decompressive surgery. It is a procedure that is simpler, quicker, less traumatic with less perineural scarring and post-operative fibrosis and has faster recovery times than the open surgical equivalent. Clinical results are very promising, but long term outcomes are pending.

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