“Sciatica” refers to pain in a sciatic-nerve distribution, but this term is sometimes used indiscriminately to describe back and leg pain. Lumbar “radiculopathy” more specifically refers to pain with possible motor and sensory disturbance in a nerve-root distribution. After lumbar stenosis, spondylolisthesis, and fracture have been ruled out, approximately 85% of patients with sciatica are found to have a herniated intervertebral disk. In two studies of surgery for sciatica, at least 95% of herniated disks were at the L4–L5 or L5–S1 levels.
Pain from disk herniation, the leading cause of sciatica, usually resolves within several weeks with conservative therapy. In patients with sciatica for 6 weeks, pain relief is faster with surgery than with conservative therapy; however, outcomes are similar at 1 year. A new Clinical Practice summarizes.
• When should a patient with a suspected herniated lumbar disk undergo magnetic resonance imaging (MRI)?
Computed tomography (CT) or MRI can confirm a clinical diagnosis of a herniated disk. Early MRI is indicated in patients with progressive or severe deficits (e.g., multiple nerve roots) or clinical findings that suggest an underlying tumor or infection. Otherwise, CT or MRI are necessary only in a patient whose condition has not improved over 4 to 6 weeks with conservative treatment and who may be a candidate for epidural glucocorticoid injections or surgery. Disk herniation does not necessarily cause pain; MRI commonly shows herniated disks in asymptomatic persons, and the prevalence of herniated disks increases with age. Thus, symptoms may be misattributed to incidental MRI findings.
• What is the likelihood that pain associated with a herniated lumbar disk will improve without surgery?
The natural history of herniated lumbar disks is generally favorable, but patients with this condition have a slower recovery than those with nonspecific back pain. In one study involving patients with a herniated disk and no indication for immediate surgery, 87% who received only oral analgesics had decreased pain at 3 months. Even in randomized trials that enrolled patients with persistent sciatica, the condition of most patients who did not undergo surgery improved.
Figure 2. CT and MRI Terminology for Herniated Disks.
Morning Report Questions
Q: What is a general approach to the management of a herniated lumbar disk?
A: Cohort studies suggest that the condition of many patients with a herniated lumbar disk improves in 6 weeks; thus, conservative therapy is generally recommended for 6 weeks in the absence of a major neurologic deficit. There is no evidence that conservative treatments change the natural history of disk herniation, but some offer slight relief of symptoms. In patients with acute disk herniation, avoidance of prolonged inactivity in order to prevent debilitation is important. The use of epidural glucocorticoid injections in patients with herniated disks has increased rapidly in recent years, although these injections are used on an off-label basis. A systematic review showed that patients with radiculopathy who received epidural glucocorticoid injections had slightly better pain relief (by 7.5 points on a 100-point scale) and functional improvement at 2 weeks than patients who received placebo. There were no significant advantages at later follow-up and no effect on long-term rates of surgery. Unless patients have major neurologic deficits, surgery is generally appropriate only in those who have nerve-root compression that is confirmed on CT or MRI, a corresponding sciatica syndrome, and no response to 6 weeks of conservative therapy. The major benefit of surgery is that relief of sciatica is faster than relief with conservative therapy, but, on average, there is a smaller advantage of surgery with respect to the magnitude of relief of back pain. Most, although not all, trials showed no significant advantage of surgery over conservative treatment with respect to relief of sciatica at 1 to 4 years of follow-up. Given these results, either surgery or conservative treatment may be a reasonable option, depending on the patient’s preferences for immediate pain relief, how averse the patient is to surgical risks, and other considerations.
Q: How common are complications when a patient undergoes lumbar diskectomy?
A: Procedural complications of lumbar diskectomy are less common than procedural complications of other types of spine surgery. A registry study indicated that an estimated 0.6 deaths per 1000 procedures had occurred at 60 days after the procedure. New or worsening neurologic deficits occur in 1 to 3% of patients, direct nerve-root injury occurs in 1 to 2%, and wound complications (e.g., infection, dehiscence, and seroma) occur in 1 to 2%. Incidental durotomy, which occurs in approximately 3% of patients, is associated with increases in the duration of surgery, blood loss during surgery, and the length of inpatient stay, as well as potential long-term effects such as headache. All tissues at the surgical site heal with some scarring, which contracts and binds nerves to surrounding structures. Normally, each nerve root glides a few millimeters in its neuroforamen with each walking step. Stretch on tethered nerves may be one source of chronic postsurgical pain.