Assessment & Diagnosis

The overriding symptom of lumbar herniated disc is severe lower back pain that radiates to the buttocks, legs, and feet, usually unilaterally. When herniation follows trauma, the pain may begin suddenly, subside in a few days, and then recur at shorter intervals and with progressive intensity. Sciatic pain follows, beginning as a dull pain in the buttocks. Valsalva’s maneuver, coughing, sneezing, and bending intensify the pain, which is commonly accompanied by muscle spasms. A herniated disc may also cause sensory and motor loss in the area innervated by the compressed spinal nerve root and, in later stages, weakness and atrophy of leg muscles.^[1]

Obtaining a careful patient history is vital because the mechanisms that intensify disc pain are diagnostically significant. The following test results support the diagnosis^[1]:

Straight-Leg Raise

The straight-leg-raising test and its variants are perhaps the best tests for diagnosing a herniated disc, but may still be negative. For this test, the patient lies in a supine position while the examiner places one hand on the ilium, to stabilize the pelvis, and the other hand under the ankle and then slowly raises the patient’s leg. The test is positive only if the patient complains of posterior leg (sciatic) pain, not back pain.

Lasegue's Test

In Lasegue’s test, the patient lies flat while the thigh and knee are flexed to a 90-degree angle. Resistance and pain, as well as loss of ankle or knee-jerk reflex, indicate spinal root compression.

X-Ray

X-rays of the spine are essential to rule out other abnormalities but may not diagnose a herniated disc because a marked disc prolapse can be present despite a normal X-ray.

Peripheral Vascular Status

Peripheral vascular status check, including posterior tibial and dorsalis pedis pulses and the skin temperature of extremities, helps rule out ischemic disease, another cause of leg pain or numbness.

Discography

Additionally, diagnostic accuracy studies show strong evidence that discography manometry provides specific diagnostic information by showing intradiscal pathology that may be missed by other studies.^[2] During a discography procedure, one or more discs are pressurized with contrast fluid. The Stryker Discomonitor^® automatically displays pressure and volume values as the dye outlines any damaged areas. As each disc is injected, the patient’s response (intensity, type, and location of the pain, if any) is monitored.

Ideal patient selection:

Radicular leg pain
MRI consistent with contained disc herniation
MRI demonstrating 50% preserved disc height
Failed conservative treatment
Facet pain excluded
Positive low-volume diagnostic SNRB
Discogram and post-disco CT consistent with the above (optional)