Cauda equina is formed by nerve roots caudal to the level of spinal cord termination. Cauda equina syndrome has been defined as low back pain, unilateral or usually bilateral symptoms in the distribution of sciatic nerve, saddle sensory disturbances, bladder and bowel dysfunction, and variable lower extremity motor and sensory loss. This may occur with neurotoxicity from local anesthesia. In the past, continuous spinal catheters with local anesthetics were associated with this syndrome. Those types of catheters and infusions are no longer in use.
Epidural steroid injections are commonly prescribed for patients with a disc injury or spinal arthritis causing nerve irritation, and generally consist of local anesthetic (numbing medication such as lidocaine) and cortisone (a steroid that reduces inflammation and pain). Lidocaine is often injected initially so patients experience minimal, if any, pain during the procedure. The injection may be performed by placing the needle posteriorly between the spine bones (Translaminar or interlaminar) and injecting the medicine into the space around the spinal nerves. A transforaminal ESI means the injection is placed slightly to one side of the spine, and the medicine is injected near the ruptured disc and inflamed spinal nerve. A caudal ESI is performed by placing the needle near the tailbone, and injecting the medicine into the region of the sacral nerves and lower lumbar spinal nerves. Epidural steroid injections, as well as most spinal injections, are performed using a special x-ray guidance system called fluoroscopy. This allows the doctor to immediately see an x-ray image on a television screen and inject the medicine precisely into the right spot. The procedure time is often less than 10-15 minutes.
Immediately after the injection, you may feel that your pain may be gone or quite less. This is due to the local anesthetic injected. This will last for a few hours. Your pain may return and you may have a sore back or neck for a day or two. This is due to the mechanical process of needle insertion as well as initial irritation form the steroid itself. You should start noticing pain relief starting the 3rd to 5th day. You should have a ride home. We advise patients to take it easy for the day of the procedure. You may want to apply ice to the affected area. After the first day, you can perform activity as tolerated. Unless there are complications, you should be able to return to your work the next day. The most common thing you may feel is soreness in the neck or back. The immediate effect is usually from the local anesthetic injected. This wears off in a few hours. The medication starts working in about 5 to 7 days and its effect can last for several days to many months. This procedure is safe when performed in a controlled setting (surgical center, sterile equipment, and the use of x-ray.) However, with any procedure there are risks, side effects, and possibility of complications. The most common side effect is discomfort – which is temporary. The other risks involve, infection, bleeding, worsening of symptoms. As with other types of injections, you should not have the procedure if you are currently taking blood-thinning medicine (Coumadin.) Side effects related to cortisone include: fluid retention, weight gain, increased blood sugar (mainly in diabetics,) elevated blood pressure, mood swings, irritability, insomnia, and suppression of body’s own natural production of cortisone. Fortunately, the serious side effects and complications are uncommon. You should discuss any specific concerns with your physician.