by Nicole Berardoni M.D, Tory McJunkin M.D, and Paul Lynch M.D
The sensory changes are often described as “pins and needles” and can extend down the buttock, leg, and foot.
Symptoms of serious concern include severe nerve impingement, bladder incontinence, bowel incontinence, lower extremity weakness, and profound loss of sensation. Loss of bowel or bladder function with sensory deficits and weakness is termed cauda equina syndrome and is a true medical emergency.
The sciatic nerve is the longest and largest nerve in the body and is commonly affected by certain conditions. The nerve exits through the lower spinal column and runs behind the hip joint, exits on the posterior side of the lower extremity (back of thigh), and continues to extend down to the foot. The sciatic nerve innervates and controls many of the muscle groups in the lower extremities and provides sensation to the thigh, leg, and foot. Sciatica refers to pain that radiates along the path of this nerve.
The sciatic nerve can be affected by many different conditions and disease states. Many of these conditions ultimately lead the nerve to become pinched or stretched. Some of the most commonly seen conditions that produce sciatica are:
- Herniated or bulging disc: This is the most common cause of sciatica. Separating each vertebra (spine bones) are discs that act as cushions to minimize the impact that the spinal column receives. Since the discs are designed to be soft and provide support, they have a tendency to herniate backwards through the outer disc segment and nearby ligaments. This disc can irritate an adjacent nerve by physical contact or by leaking caustic substances directly onto the nerve. Disc disease is one of the most common causes of chronic lower back pain and accounts for approximately 10% of all low back pain complaints.
- Spinal stenosis: This is a disorder due to narrowing of the spinal canal that causes nerve or spinal cord impingement. The condition often results in persistent pain in the lower back and lower extremities. Difficulty walking, decreased sensation in the lower extremities, and decreased physical activity may also be experienced. Many people with spinal stenosis present with bilateral (both sides) sciatica.
- Piriformis syndrome: The piriformis is a large muscle that is part of the pelvis. When this muscle becomes inflamed or overused, this muscle can trap the sciatic nerve deep in the buttock causing sciatica.
- Facet hypertrophy: The facet joints allow for movement, especially backwards extension. When the facet joints become arthritic they can become knobby and large. They also can develop cysts. The larger joints can irritate exiting nerve roots causing sciatica.
- Other causes: Less commonly, sciatica can be due to tumors, pelvic infections, and other causes.
Diagnosis of sciatica is most often done clinically by a medical physician. The physician performs a physical examination demonstrating tenderness over certain areas of the spine as well as assessing the various limitations in movement of the lower extremity.
The physician may also order radiological imaging such as X-ray, CT scan, MRI, or bone scan depending on his clinical suspicion. Currently MRIs are the standard of care to visualize chronic back pain and are especially useful before any procedures are undertaken. If a history of cancer, IV drug use, HIV infection, or recent steroid use is known then the physician will most likely order additional studies before deciding on sciatica therapy.
- Pharmacotherapy: NSAIDs (ibuprofen-like drugs), acetaminophen, membrane-stabilizing drugs, muscle relaxants, and other analgesics are often used in the management of pain associated with sciatica.
- Epidural steroid injections (ESI): This procedure involves injecting a medication into the epidural space where the actual irritated nerve root is located. This injection includes both a long-lasting steroid and a local anesthetic (lidocaine, bupivacaine). The steroid reduces the inflammation and irritation and the anesthetic works to interrupt the pain-spasm cycle and nociceptor (pain signal) transmission (Boswell 2007). The combination medicine then spreads to other levels and portions of the spine, reducing inflammation and irritation. This sciatica treatment usually takes less than 15 minutes. The most important and greatest success achieved with the use of epidural steroid injections (ESI) is the rapid relief of symptoms that allows patients to experience enough relief to become active again. With this they regain the ability to resume their normal daily activities. A large study in 2005 including 228 patients with a clinical diagnosis of unilateral sciatica were randomized to either three lumbar ESIs or a placebo injection at intervals of three weeks. The ESI group demonstrated a 75% pain improvement over the placebo group (Arden 2005).
- Lysis of adhesions: Also known as the “Racz procedure,” this sciatica therapy has proven effective in removing excessive scar tissue in the epidural space when conservative treatment has failed. A study performed in 2005 noted that: “a spinal adhesiolysis with targeted delivery of local anesthetic and steroid is an effective treatment in a significant number of patients with chronic low back and lower extremity pain without major adverse effects.”
- Infusion techniques: This procedure involves inserting a small catheter through a needle into the epidural space or directly next to affected nerves. Local anesthetic and other medicines are often given through the catheter for extended time periods. When the nerves are blocked continuously with an infusion, pain relief can be dramatic and long-lasting.
- Transcutaneous electrical stimulation (TENs): This pain relief technique is a passive process with no known side effects. TENS decreases the perception of pain and may be used to control acute and chronic pain. There are several patches placed on your skin in the area that is affected and mild electrical current generates stimuli. This stimuli confuses the spinal cord and brain pain processing centers. Painful signals are replaced by tingling electrical signals in this sciatica treatment. This provides relaxation of the muscle, improves mobility, and can relieve pain.
- Spinal cord stimulation (SCS): An implanted electrical device can decrease the perception of pain by confusing the spinal cord and brain pain processing centers. Initially a trial is done to see if this device will help you long-term. In the initial trial, your pain physician places a small electrical lead through a needle in the epidural space. Painful signals are replaced by tingling electrical signals. If you have success in your trial, you may decide to have a permanent SCS device implanted.
- Deep tissue massage: Focal rubbing of tender areas may help relieve muscle spasms or contractions and improve the discomfort associated with it. Massage as a sciatica therapy can also help you relax, decreasing stress and tension.
- Acupuncture: Small needles are inserted into the skin. These needles cause your body to release hormones called endorphins, which are your body’s natural pain relievers. Acupuncture can also help you relax, decreasing stress, tension, and muscular spasm.
- Physical therapy: Physical therapy helps improve symptoms of sciatica by increasing flexibility, range of motion, posture, and improving muscle strength.
- Nutrition and exercise: Exercise improves the pain of sciatica by increasing flexibility and range of motion. Another benefit is the release of hormones called endorphins, which are your body’s natural pain relievers. Nutrition and healthy eating may be powerful treatments to combat nutritional deficits.
- Intrathecal pump implants: Implanted pain pumps are also available that can be extremely helpful at providing long-term pain control. The effectiveness of intrathecal sciatica therapy in patients suffering from nociceptive pain showed a pain reduction in 66.7% of patients experiencing pain due to cancer (Becker 2000).
- Disc decompression: A needle is inserted through the skin into the affected disc. Disc material is suctioned out of the bulging disc and pressure is relieved within the disc.
- Trigger point injections (TPIs): These can be an effective treatment for muscle spasms. The procedure involves injecting a local anesthetic and steroid into a trigger Point. Performing a piriformis injection can be considered a type of TPI.
- Botox: Used in treating neck pain, this is an exciting new treatment that is widely accepted among modern medicine. In 2005, “Botulinum toxin Type A (BtA) became the first-line therapy for the treatment for cervical dystonia.” Although a single injection of BtA is effective, multiple injection cycles seem to work better for patients (Costa 2005). Botox injections have also been found to be effective in patients with whiplash injuries. Along with reductions in pain, patients were found to have improved range of motion (Juan 2004).
- Biofeedback: This is a treatment that teaches a patient to become aware of processes that are normally thought to be involuntary inside of the body (such as blood pressure, temperature, and heart rate control). This method enables you to gain some conscious control of these processes, which can influence and improve your level of pain. A better awareness of one’s body teaches one to effectively relax, and this can help to relieve pain.
- Rheumatology (Oxford). 2005 Nov;44(11):1399-406. Epub 2005 Jul 19 Arden NK, Price C, Reading I, Stubbing J, Hazelgrove J, Dunne C, Michel M, Rogers P, Cooper C; WEST Study Group. Rheumatology (Oxford). 2005 Nov;44(11):1399-406. Epub 2005 Jul 19 PMID: 16030082
- Interventional Techniques: Evidence-based Practice Guidelines in the Management of Chronic Spinal Pain. Boswell et. All. Pain Physician 2007; 10:7-111