Osteoporosis

Rotation. Place one hand on the pelvis and the other on the opposite shoulder. Rotate the pelvis and shoulder posteriorly and repeat on the other side; note any asymmetry in motion.

SPECIFIC TESTS

Two specific tests include the straight-leg raise test and the crossed straight-leg raise test. These are valuable diagnostic tools for disk herniation and lumbosacral radiculopathy.

Straight-Leg Raise Test. To perform, have the patient lie supine with legs relaxed. Lift the patient’s leg upward by supporting the heel with one hand and ensuring the knee remains straight with the other hand; when the patient experiences pain, lower the leg slightly and dorsiflex the foot to stretch the sciatic nerve. Note the degree of elevation, description and location of pain, and effect of dorsiflexion. The test is positive if pain is felt in the low back or along the sciatic nerve. A positive test is indicative of lumbosacral radicular inflammation.

Crossed Straight-Leg Raise Test. To perform, place the patient in supine position, raise the unaffected leg. If back or sciatic pain is felt in the opposite leg, this is suggestive of a lesion, such as a herniated disk, in the lumbar region.

REFLEX TESTING

Patellar muscle stretch reflex arises predominantly from L4 nerve roots, although innervation is also supplied by L2 and L3 segments of the spinal cord. Damage to the L4 nerve will elicit a significantly decreased patellar reflex due to L2 and L3 involvement.

Achilles muscle stretch reflex typically involves the S1 nerve root. Dorsiflex the foot and strike the tendon to elicit plantar flexion of the foot.

IMPORTANT FINDINGS

Mechanical low back pain characterized by aching pain in the lumbosacral region presents with paraspinal muscle or facet tenderness but no evidence of motor, sensory, or reflex deficits.

Radicular low back pain is typified by pain that extends below the buttocks into the posterior thigh and often below the knee into the lateral leg or back of the calf. Clinical findings in sciatica due to disk herniation include decreased ankle dorsiflexion, tibialis anterior and tibialis posterior (L5) or gastrocnemius (S1) weakness, no ankle jerk (S1), and positive crossed straight-leg test.

Lumbar spinal stenosis findings are variable. Classically, patients complain of pain with standing or walking, particularly with hyperextension such as walking downhill; this is relieved with rest or flexion. Anterior thigh paresthesias are common. Often, there are no significant abnormal findings; however, there may be mild proximal, quadriceps, and iliopsoas (L3-4), weakness with a decreased patellar reflex. Straight-leg raising is normal.

DIAGNOSTIC IMAGING

Although imaging or other diagnostic tests need not be obtained routinely in patients early in the course of acute or subacute nonspecific LBP, they are irreplaceable in the management of patients with severe or progressive neurologic deficits or with other serious underlying conditions.

Plain radiography is of limited use, as it fails to depict a detailed picture of the disease; however, it has been recommended for initial evaluation of possible vertebral compression fracture in patients with a history of osteoporosis or steroid use.

Magnetic resonance imaging (MRI) provides superior soft tissue detail compared with computed tomography (CT) and plain radiography. It is the method of choice for visualization of intrathecal nerve roots, detecting intraspinal malignancy and infection within the spine, as well as bone marrow evaluation. MR imaging is less useful for detecting acute spinal fractures.

CT scans are particularly valuable for detecting traumatic and degenerative changes in cortical bone and have a good sensitivity for detecting herniated disks. It can also demonstrate foraminal and extraforaminal nerve root impingement. CT is superior to plain films for detecting infection and neoplasm.

LABORATORY EVALUATION

This is primarily useful in the clinical setting suggestive of visceral or other nonmechanical causes for the pain. Initial studies of value are complete blood count, erythrocyte sedimentation rate, and C-reactive protein, whereas urinalysis, prostate-specific antigen, alkaline phosphatase, and protein immunophoresis are valuable when there are clinical clues suggesting urinary infection and malignant or metabolic disease.

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