Low back pain is one of the leading causes of lost work time, second only to the common cold. It affects 65-85% of the population of the United States at some point in their lives. The most common cause is a sprain, strain or spasm usually brought on by poor lifting technique, improper posture, bad back habits, or an unhealthy ergonomic environment. Another common cause is disc problems, brought on by injury, wear and tear, or age. Other causes include a narrowing of the spinal or nerve canals, arthritic or degenerative changes in the small joints of the back, osteoporotic fractures, and sometimes even infections or tumors.
Discs act as the shock absorbers between the vertebrae of the spine; they are tough, fibrous, outer-shelled discs (the annulus) that are filled with gel (the nucleus). In a healthy back, discs allow the spine to be flexible. Unfortunately, time, trauma, and inherent weakness in a disc can lead to degeneration of the annulus causing the nucleus of the disc to bulge out or even herniate (extrude) through the wall of the annulus.
These injuries can actually be verified by MRI or CT scans. Interestingly enough, scans can sometimes show such abnormalities in patients that report no back pain, but we have yet to understand why. At any rate, a degenerated disc can be the source of back pain, and if the bulging disc is pressing on a spinal nerve root, the pain can radiate into the leg causing sciatica.
Until now treatment options have been limited. Physical therapy can help to ease the painful muscles, which struggle to cope with the spine problem, and PT can also help to prevent abnormal stresses on the spine. Epidural steroid injections can reduce the inflammation in the area and are often helpful, but the pain tends to recur if the underlying problem is severe. For acute problems, the only remaining treatments have been to surgically remove part of the disc, or to surgically fuse the vertebrae to remove pressure on the disc.
Now there are some unproven minimally-invasive procedures available that may help with the treatment of back pain and sciatica known as Radiofrequency Discal Procedures—among them is something called an Intradiscal Biacuplasty (IDB).
Radiofrequency Discal Procedures
Nucleoplasty is a type of Radiofrequency Discal Procedure that involves inserting a very thin needle into the disc but instead of using a heating wire (as was previously done in a technique known as Intradiscal Electrothermoplasty, or IDET), a special radiofrequency probe is inserted through the needle into the disc. This probe generates a highly focused plasma field with enough energy to break up the molecular bonds of the gel in the nucleus, essentially vaporizing some of the nucleus. The result is that 10-20% of the nucleus is removed which decompresses the disc and reduces the pressure both on the disc and the surrounding nerve roots. This technique may be beneficial for sciatica type of pain than the IDET, since nucleoplasty can actually reduce the disc bulge, which is pressing on a nerve root. The high-energy plasma field is actually generated at relatively low temperatures, so danger to surrounding tissues is minimized.
Another procedure called Intradiscal Biacuplasty (IDB) is an advanced type of radiofrequency ablation that also treats discs from the inside. It is currently the technique with the most interest—and recent support—in the research literature, but there is nevertheless concern about intradiscal procedures. Some research has shown that needle puncture of the disc can enhance and hasten disc degeneration however, the risk-benefit for these procedure is still unclear.
These new techniques are exciting. They offer the possibility of treating discogenic low back pain and sciatica with much less trauma and risk than surgery, but it's important to remember that these are still unproven technologies. I'll keep you posted on how research on these techniques develops, but it's great that we have some new tools to help people with this often debilitating problem.
Spinal Stimulators and Pumps for Pain Relief
Spinal Pumps are called intrathecal (intra-thee-cal) spinal pumps and can be used to deliver a continuous flow of pain relieving medication. Intrathecal refers to the fluid containing space that surrounds the spinal cord. The benefit of administering pain relieving medication through a spinal pump is that medications taken orally are diffused throughout the entire body. A spinal pump delivers pain-relieving medication precisely where it is needed. (Ziconotide is a non-opiod medication that is now being used in spinal pumps and can be effective for treating a wide variety of chronic pain conditions, including sciatica. It is not an addictive medication.) This treatment is considered after standard conservative treatments have been ineffective or have caused intolerable side effects.
The pump is surgically implanted beneath the skin of the patient's abdomen. A catheter is run to the level of the spine from where pain is transmitted. Medication is pumped directly into the spinal fluid allowing for a much more potent effect on the spinal cord. This drastically cuts down on the amount of medication needed and provides better pain relief with fewer side effects.
The pump is refilled every 1-3 months by inserting a needle through the skin and into a diaphragm on the surface of the pump. Several different medications can be administered this way. Since the system is beneath the skin, the risk of infection is minimized and the patient can be fully mobile and active.
Spinal Stimulators emit electrical pulses on the surface of the spinal cord to reduce pain. The stimulators are similar to pumps in that they are surgically implanted beneath the skin but differ in that electrical signals, rather than medication, are used to ease pain.
Electrical signals are passed through the tip of the catheter at the precise location near the involved segment of the spinal cord. The result is a tingling sensation, which eases pain. Current theory is that the electrical current input alters the spine's processing of the pain so that the patient's pain is reduced. The patient is able to control the stimulator by holding a magnetic pulsing device over the skin on top of the implanted generator disk. The stimulator appears to be effective for patients with back and leg pain that spinal surgery did not relieve. There is data that shows that these patients will do better with the placement of a stimulator than they will with repeat surgery.
This approach is growing in use for chronic neck and back pain problems that have failed to respond to simpler treatments. New devices, such as the Nevro high frequency stimulator, are now available. These new devices may expand the utility and success of implanted stimulators for back pain.