As a disc degenerates, the inner core of the disc can extrude—or herniate—back into the spinal canal. The herniated disc material can irritate the nerve, which can cause pain to radiate down the path of the nerve - from the lower back through the buttocks and into the leg or even into the foot.

Anatomy of a herniated disc
Discs are positioned in between each vertebra (the bony building blocks of the spine) along the front of the spine. Each disc is composed of a tough outer ring and a soft inner core, which is the part that extrudes, or “herniates” out.

A lumbar (lower back) disc herniation typically occurs toward the back of the spine where there is a thinner boundary in the outer ring. This weak spot in the disc can be directly under the nerve root.

Symptoms
A lumbar herniated disc will typically cause one or a combination of the following symptoms:

• Dull or sharp pain that travels into the buttocks and back of the leg (sciatica)

• Numbness or tingling in different areas of the leg

• Muscle weakness in certain muscles of one or both legs

• Loss of some reflexes in the leg

Sitting or bending forward, and sneezing or coughing, will usually make the pain worse. If symptoms include any bowel or bladder dysfunction, or there is progressive weakness in the legs, immediate medical attention should be sought.

The specific symptoms of a herniated disc depend primarily on the location and degree of the herniation. Approximately 90% of lumbar disc herniations will occur at the following segments of the lower spine:

• L4-L5 herniation (between lumbar segment 4 and 5)—Can cause weakness in extension of the big toe and potentially in the ankle (foot drop). Numbness and pain may be felt on top of the foot, and the pain may also radiate into the buttocks.

• L5-S1 herniation (between lumbar segment 5 and sacral segment 1)—May cause loss of the ankle reflex and/or weakness with ankle push off (e.g. patients cannot do toe rises). Numbness and pain can radiate down to the sole or outside of the foot.

Diagnosis
A detailed medical history and physical examination can usually differentiate a herniated disc from other possible conditions that can cause similar symptoms. An MRI scan is usually needed to confirm the diagnosis and understand the location and degree of the herniation, and additional diagnostic tests may be needed to rule out other possible causes of the symptoms.

Many disc herniations do not actually cause any symptoms, so an MRI scan that shows a herniated disc does not necessarily mean that the herniation is causing the pain. It is important to get an accurate diagnosis from a doctor that correlates the patient’s medical history and physical exam with the imaging tests.

Treatment for a lumbar disc herniation will largely depend on the length of time the patient has had his or her symptoms and the severity of the pain. For most patients, symptoms from a lumbar disc herniation will go away over time. While there are no hard and fast rules, this article reviews some general guidelines for non-surgical and surgical treatment options.

Generally, patients will start with 6 to 12 weeks of conservative (meaning non-surgical) treatment. Surgery may be considered if a course of conservative treatment does not provide pain relief, or if the pain is severe and the patient is having difficulty functioning.

Conservative (non-surgical) treatments
The primary goals of treatment are to provide pain relief and to allow the patient to return to a normal level of activity.  If the symptoms start to abate within the six-week period, continued conservative treatment is warranted.  Depending on the patient’s clinical situation and physician’s recommendations, one or several of the following non-surgical treatments may typically be considered:

• Physical therapy, exercise and gentle stretching to help relieve pressure on the nerve root

• Ice and heat therapy for pain relief

• Manipulation (such as by a chiropractor, osteopath, or appropriately trained physical therapist)

• Non-steroidal anti-inflammatory drugs, "NSAIDs" (such as ibuprofen or naproxen)

• Narcotic pain medications for pain relief

• Oral steroids or epidural steroid injections to decrease inflammation for pain relief

It may be necessary for a patient to try more than one or a combination of the above treatments. The recommended length of conservative treatment for patients needs to be individualized. For those patients who are not in severe pain and can function well, a longer period of conservative treatment is reasonable. The vast majorities of people with a lumbar disc herniation do not need surgery and will recover and return to their normal lifestyle within several weeks or months of conservative treatment.

Surgical treatments
The goal of surgery is to help alleviate the pain faster. If a patient has severe pain and is unable to function at a satisfactory level, surgery may be a reasonable option even before six weeks of symptoms. In recent years, the morbidity (or unwanted side effects, such as post-operative pain) of surgery for a lumbar herniated disc has decreased and the results have improved, so surgery is generally considered a reasonable option for relieving pain and other neurological symptoms more quickly.

The most common surgery to treat a lumbar herniated disc is a microdiscectomy (microdecompression). This is a minimally-invasive procedure (since the incision is small and muscles are moved rather than cut) to remove the herniated portion of the disc under the nerve root. By giving the nerve root more space, pressure is relieved and the nerve root can begin to heal. The microdiscectomy procedure is usually highly successful for relieving the leg pain (sciatica) caused by a herniated disc. Although the nerve root takes several weeks or months to fully heal, patients often feel immediate relief of their leg pain and usually have a minimal amount of discomfort following the surgery. Depending on the patient’s clinical situation and surgeon’s preference, a lumbar laminectomy (open decompression), arthroscopic lumbar discectomy (endoscopic percutaneous discectomy), or microendoscopic surgery may also be considered.

Any patient who has progressive neurological deficits or develops the sudden onset of bowel or bladder dysfunction should have an immediate surgical evaluation, as these conditions may represent a surgical emergency. Fortunately, these conditions are rare.