Herniated Disc
Definition
A herniated disc is a fragment of the disc nucleus, which is pushed out of the outer disc margin, into the spinal canal through a tear or "rupture." In the herniated disc's new position, it presses on spinal nerves, producing pain down the accompanying leg. This produces a sharp, severe pain down the entire leg and into the foot. The spinal canal has limited space, which is inadequate for the spinal nerve and the displaced herniated disc fragment.
The compression and subsequent inflammation is directly responsible for the pain one feels down the leg, termed "sciatica." The direct compression of the nerve may produce weakness in the leg or foot in a specific patter, depending upon which spinal nerve is compressed.
A herniated disc is a definite displaced fragment of nucleus pushed out through a tear in the outer layer of the disc (annulus). For a disc to become herniated, it typically is in an early stage of degeneration.
Typical Pain and Findings
Typically, a herniated disc is preceded by an episode of low back pain or a long history of intermittent episodes of low back pain. However, when the nucleus actually herniates out through the annulus and compresses the spinal nerve, then the pain typically changes from back pain to sciatica. Sciatica is sharp pain, which radiates from the low back area down through the leg, into the foot in a characteristic pattern, depending upon the spinal nerve affected. This pain often is described as sharp, electric shock-like, sever with standing, walking or sitting. The pain is frequently relieved by lying down or utilizing a lumbar support chair or insert.
There also may be resulting leg muscle weakness from a compromise of the spinal nerve affected. Most commonly, the back pain has resolved by the time sciatica develops, or there is minimal back pain compared to the severe leg pain. The location of the leg pain is usually so specific that the doctor can identify the disc level which is herniated. In addition to leg muscle weakness, there may also be knee or ankle reflex loss.
Treatment
The initial treatment for a herniated disc is usually conservative, i.e. nonoperative. One usually begins with resting the low back area, maintaining a comfortable posture and painless activity level for a few days to several weeks. This in in order to allow the spinal nerve inflammation to quiet down and resolve.
A herniated disc is frequently aided by non-steroidal anti-inflammatory medications. An epidural steroid injection may be performed utilizing a spinal needle under x-ray guidance to direct the medication to the exact level of the disc herniation.
Physical therapy may be beneficial, under the direction of a physical therapist. The therapist will perform an in-depth evaluation; this information, combined with a physician's diagnosis, will dictate a treatment based on successful physical therapy treatment modalities which have proven beneficial for herniated disc patients. These may include traction, ultrasound, electrical muscle stimulation, etc., to relax the muscles which are in spasm and secondarily inflamed from the compressed spinal nerve. Pain medication and muscle relaxing medications may also be beneficial to help physical therapy or other conservative, non-operative treatment to relieve the pain while the spinal nerve root inflammation resolves and the body heals itself. If these conservative treatments are not successful and the pain is still severe or muscle weakness is increasing, then surgery is necessary. Surgery may be in the form of a percutaneous discectomy if the disc herniation is small and not a completely extruded disc fragment.
If the herniation is large, or is a "free fragment" as described above, then a microlaminotomy with disc excision is necessary. A micro-laminotomy requires one to two days of hospitalization after the surgery for the wound to heal and postoperative physical therapy to begin. The sciatic pain down the leg should be resolved immediately after the surgery. However, there will be some discomfort in the low back area where the operation is performed, lasting several days to a couple of weeks. This is controlled with pain medication.
Reproduced with permission from the American Association of Neurological Surgeons 5550 Meadowbrook Dr., Rolling Meadows, IL 60008; www.neurosurgerytoday.org, 2005