The lumbar disc primarily consists of both an outer layer of firm tissue called the annulus, and the softer inner contents called the nucleus pulposus. Stretching or a tear of the annulus can result in the inner, softer disc material entering the spinal canal through the hole in the annulus, resulting in a herniated disc.
Depending on the exact size and location of the disc herniation, a spinal nerve can be compressed, potentially causing leg and/or back pain, numbness, tingling and weakness. A herniated disc can be caused by an acute back strain, but commonly patients do not recall any particular activity or event that preceded the onset of symptoms.
Although plain X-rays are commonly obtained in the work-up of back and leg pain, a herniated disc, being composed of soft tissue rather than bone, will not be seen on x-ray. Lumbar herniated discs are most readily diagnosed with a standard MRI without contrast. In patients in whom an MRI is unobtainable, CT myelography can also be utilized.
Nonoperative treatment consisting of modalities such as rest, non-steroidal anti-inflammatory medication, oral steroids, epidural steroids, and physical therapy are the mainstays of initial treatment. The vast majority of patients with new onset symptoms will significantly improve within 3 months and not require surgery. Surgery is commonly indicated after a trial of nonoperative therapy has not provided adequate relief of symptoms, or in patients who initially present with significant weakness or bowel and bladder symptoms. Microdiscectomy is the most commonly recommended surgical procedure, and can be performed using minimally invasively on an outpatient basis.