Lumbar Disc Herniation

Procedure

Patient sits upright at the edge of the plinth, hands behind the back. In sequence: slump the thoracic and lumbar spine, flex the neck (chin to chest), extend the knee on the tested side, then dorsiflex the ankle. Stop at the first symptoms. Then ask the patient to lift the head (release neck flexion) and note any change.

Positive Finding

The patient's familiar leg symptoms reproduced in the slumped position and eased when the neck is released.

Sensitivity / Specificity

Reference: Majlesi J, Togay H, Unalan H, Toprak S. The sensitivity and specificity of the Slump and the Straight Leg Raising tests in patients with lumbar disc herniation. J Clin Rheumatol. 2008;14(2):87-91.

Interpretation

A positive slump with relief on neck release suggests the leg pain is coming from irritable neural tissue, consistent with nerve-root irritation. Many people feel a normal stretch behind the knee in this position, so compare sides and look for the patient's own symptoms. From one case-control study (Majlesi 2008) of 75 outpatients with back and/or leg pain: 38 had a disc herniation on MRI and 37 did not. The comparison patients had symptoms too, which is the fair comparison. But a herniation on MRI is not always the cause of the pain. In the same patients the straight leg raise scored 52% / 89%.

Procedure

Patient supine, legs straight, no pillow under the head. Lift the symptomatic leg slowly with the knee held straight until the patient reports symptoms. Note the angle and where the symptoms are felt, then add ankle dorsiflexion to see whether the leg pain increases.

Positive Finding

The patient's familiar radiating leg pain, usually below the knee, reproduced as the leg is raised and increased by ankle dorsiflexion. Back pain alone or a posterior thigh stretch does not count.

Sensitivity / Specificity

Reference: van der Windt DA, Simons E, Riphagen II, Ammendolia C, Verhagen AP, Laslett M, et al. Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain. Cochrane Database Syst Rev. 2010.

Interpretation

A negative SLR makes a disc herniation causing leg pain less likely. A positive SLR supports lumbar nerve-root irritation from a herniation, but on its own proves little. Combine it with the crossed SLR, the neurological examination and the history. Imaging is only needed if it will change management, for example when surgery is being considered. Pooled in a 2010 Cochrane review (van der Windt) from studies where surgery confirmed the diagnosis. Those patients were already selected for surgery (58–98% had a herniation), so specificity is poorly estimated, and sensitivity was lower in studies that used imaging or were done in primary care. A negative SLR makes a disc herniation causing leg pain less likely; a positive SLR on its own proves little.

Procedure

Patient supine. Lift the unaffected leg with the knee straight, as in the standard SLR, while the patient reports any symptoms in the painful leg.

Positive Finding

Reproduction of the familiar radiating pain in the symptomatic leg when the opposite leg is raised.

Sensitivity / Specificity

Reference: van der Windt DA, Simons E, Riphagen II, Ammendolia C, Verhagen AP, Laslett M, et al. Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain. Cochrane Database Syst Rev. 2010.

Interpretation

Usually negative, so a negative result does not rule out a herniation. When it is positive, a disc herniation compressing the nerve root is much more likely, and it has been linked to larger herniations. Check the neurological examination and red flags carefully. Pooled in a 2010 Cochrane review (van der Windt), mostly from surgical populations. A positive crossed SLR makes a disc herniation more likely; because it is usually negative, a negative result does not rule one out.

Procedure

Perform the straight leg raise to the point where leg symptoms first appear. Hold the leg there and ask the patient to lift the head, bringing the chin towards the chest (or flex the neck passively).

Positive Finding

The leg symptoms increase when the neck is flexed. Neck flexion tensions the spinal cord and nerve roots from above without moving the hamstrings.

Interpretation

An increase in symptoms with neck flexion suggests the leg pain comes from neural tissue rather than the hamstring. No change does not exclude nerve involvement. Note: Lasègue's sign is the classic name for the straight leg raise itself; this entry previously described neck flexion as relieving pain, which is incorrect.

Procedure

Patient prone. Bend the knee towards the buttock; if no symptoms appear, gently extend the hip while stabilising the pelvis. Compare with the other side.

Positive Finding

Reproduction of the patient's familiar pain in the front of the thigh or groin. A stretch felt only in the quadriceps does not count.

Interpretation

Tensions the femoral nerve and the L2–L4 nerve roots. A positive test points to an upper lumbar root (less common herniation levels) rather than L5 or S1. A negative test does not exclude an upper lumbar herniation. Follow with knee-extension strength, the patellar reflex and sensation over the front of the thigh and medial shin. From a study of 54 people with leg pain and a compressed nerve root on MRI, examined by doctors who had not seen the scan (Suri 2011). The test was positive in half of those with an L2, L3 or L4 root compressed and in none of the 29 with an L5 or S1 root compressed. So it helps tell a higher lumbar root from the common L5/S1 level; it does not show whether a root is compressed at all. The study was small, and everyone in it had a compressed root, so these figures are shown here as a note and not as test accuracy.

Procedure

Test lower-limb strength by myotome (hip flexion L2, knee extension L3–4, ankle dorsiflexion L4, big-toe extension L5, plantarflexion S1), light-touch and pin-prick sensation by dermatome, and the patellar (L4) and Achilles (S1) reflexes. Compare with the other side.

Positive Finding

Weakness, altered sensation or a reduced reflex that fits one nerve root and matches the side of the leg pain.

Interpretation

A matching deficit supports nerve-root compression and suggests the level. A normal examination does not exclude a herniation. Progressive weakness, bladder or bowel change, or saddle numbness needs same-day medical assessment.