Low back and leg pain has many causes, one of which is scarring in the epidural space. Epidural scarring can cause back and leg pain for many reasons. The nerves can be trapped by scars and unable to move when you change position. Veins in the epidural space press down upon (the nerves?) and become large, putting pressure on the nerves. The sac that holds the cerebral spinal fluid in place, the dura, can get attached to the wall of the epidural space and cause pain in the lower back and legs. Scarring can prevent medicine put into the epidural space to treat pain from getting to the nerves.
Scarring can arise for many reasons. Anyone who has had spine surgery will have scarring. This scarring can lead to post lumbar surgery syndrome or failed back surgery syndrome. Epidural bleeding (hematomas) and infection can cause scarring. Epidural scarring causing low back and leg pain can come about simply as a result of the aging process, as arthritis sets into the spinal column. MRIs are relatively inaccurate in identifying fibrosis after lumbar spinal surgery.
One sign of epidural scarring is evident in the “dural tug,” where the patient sits on the exam table with the legs stretched out. Bending forward will bring on the back pain. After a successful adhesiolysis, bending forward will no longer be painful.
Percutaneous adhesiolysis is a procedure which can provide relief in patients who have not responded to epidurals, physical therapy or medications. Percutaneous adhesiolysis is also called the Racz procedure, after Gabor Racz, M.D., who developed it. It is an outpatient procedure, similar to an epidural, from the point of view of the person having the procedure. Adhesiolysis is well tolerated and patients into their eighties and nineties can safely have it. The purpose is to break up any scarring which might occur in the epidural space. Scarring can come about from surgery or simply from aging of the spine. There are many veins in the epidural space and as arthritic changes set in, these veins can tear and cause tiny bleeds. Each little tear and bleed on its own is of no matter. Over time, however, they can cause scarring which can prevent the nerves or the dura from moving. This scarring can occur either around the nerve root or it can attach the dura, the lining that keeps the cerebral spinal fluid in place, to the lining of the spinal canal. Nerves can be tethered or veins can become swelling, pressing on the nerves. Either way, the nerve, or the dura, can cause pain.
What we do with epidural adhesiolysis is to try to break up this scarring. The first thing we want to do is to confirm that scarring is present. This can be done on a MRI, with contrast. We can also show adhesions by looking at the flow of dye when we do an epidural. Scarring will cause an area where the dye will not flow. If there is scarring in a part of the epidural space that could be causing your pain, then an adhesiolysis procedure is a good option.
We do is to pass a special spring wound catheter to the area of scarring. This catheter is soft enough to not damage the nerve. It is firm enough to be steerable and, because it has the wire spring in it, it is very unlikely that it will be cut. We first inject some dye to confirm that the scarring in present. We then use this catheter to do a mechanical lysis of adhesions, breaking up the scarring. We then inject more dye to show that we have dye where the dye previously did not go and that the scarring is decreased. There will usually be some residual scarring, so we then inject local anesthetic and steroid and saline (salt water, just like salt water we have in our body.) You may have saline that is just like what we have in our body or you may get a more concentrated form of saline, 10% hypertonic saline, which will expand eleven-fold and place more pressure on the remaining scar. Sometimes, we use an enzyme called hyaluronidase to help the spread of the fluid, although hyaluronidase works only on normal tissue and does not itself break up scars.
All of the components of adhesiolysis help break up the scar from the inside. Another way to break up the scar is to pull on the nerve, like tugging on a rope. To do this, we will ask you to do some exercises at home. These include bringing your knees up to your chest and bringing your legs straight up in the air and then spread them in and out. In this manner, we bring in every tool possible to break up the scar, mechanically breaking it up with the catheter, using fluids to open the space and using motion of the nerves themselves to free the nerves up.
You may return to your normal activities the day after the procedure.
Adhesiolysis is generally a safe procedure. Like any procedure, you can have localized discomfort, infection or hematoma. If hypertonic saline is used, we use great care to make sure it does not go into the subarachnoid space. You will get a full discussion of the procedure and risks prior to the procedure.
There is high quality evidence to show that adhesiolysis works in patients who have had lumbar spine surgery and who have spinal stenosis or disc protrusions. There was recently an excellent randomized trial out of four centers in Germany where they compared adhesiolysis to a placebo, with adhesiolysis being very effective.
Another way of treating epidural scarring and relieving lower back or leg pain is with epiduroscopy. Epiduroscopy involves placing a catheter with a fiberoptic scope in it into the epidural space. In this way, the epidural scarring, along with nerve roots, disc herniations and other structures in the disc can be directly looked. In its simplest form, the epiduroscope itself is used to break up scarring. In some settings, a laser is used to burn scarring and to reduce disc herniations.
Epiduroscopy is a useful, unique tool to treat epidural scarring and other pathology in the epidural space; therefore, relieving the patient of any low back or leg pain.
Adhesiolysis and epiduroscopy
Adhesiolysis and epiduroscopy, like every procedure, have complications. In the hands of a skilled physician, the risks of the procedures are minimal. You should discuss, as with any procedure, the risks and benefits prior to undergoing surgery.
Many insurers have elected to not cover adhesiolysis or endoscopy, despite evidence showing that it provides significant and sustained low back and leg pain relief in many patients who otherwise do not have relief from pain. Given how much relief these procedure can provide in patients who would continue to suffer, they are useful and important tools in treating low back pain arising from epidural scarring.