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Low Back Pain Clinical

Low Back Pain Clinical


A thorough history and physical examination is paramount to arrive at a diagnosis, and initially imaging is often unnecessary.

  • Patients most often complain of pain in the lumbosacral area.
    • Determine whether pain is exacerbated by movement or by prolonged sitting or standing.
    • Determine the duration of pain.
    • Determine if pain is relieved by lying down.
    • Establish if pain was sudden in onset or gradual over days or months.
    • Determine if pain is worse in the morning or at night.
    • Find out if the patient can identify a precipitating event such as lifting or moving furniture.
  • Explore the presence of systemic symptoms such as fever, weight loss, dysuria, cough, and bowel or bladder problems.
  • Inquire about current medications that may produce symptomatology.
    • Chronic steroids may predispose to infection or compression fractures.
    • Anticoagulants may result in a bleed or hematoma.
  • Any history of new-onset bowel or bladder dysfunction (eg, urinary hesitancy, overflow incontinence) with back pain is suggestive of cauda equina syndrome. This is particularly true if other, new neurologic deficits are also present.


  • Physical examination of a patient with back pain should include range of motion and a thorough neurologic examination, including assessment of peripheral motor function, sensation, and deep tendon reflexes.
    • Perform straight leg testing with the patient in a supine position. Record response to raising each leg. An approximation of the test may also be performed with the patient sitting and each leg straightened at the knee. An elevation of the leg to less than 60° is abnormal. The straight leg test result is positive only if the pain radiates to below the knee and not merely in the back or the hamstrings. This is the single best test for determining radiculopathy due to disc herniation with a high sensitivity and moderate specificity.
    • Perform an abdominal examination to exclude intra-abdominal pathology.
    • Perform a rectal examination on men older than 50 years to assess prostate size and exclude prostatitis. Also perform a rectal examination on any patient who may have cauda equina syndrome to assess rectal tone and perineal sensation. If cauda equina syndrome is suspected, urinary catheterization for a postvoid residual or bedside ultrasonography of the bladder may be helpful to assess for urinary retention.
    • Perform a rectal examination, if necessary, in younger males who are febrile and have urinary complaints.
    • Perform a pelvic examination, if necessary, in females complaining of menstrual abnormalities or vaginal discharge.
  • Patients with true herniated discs may not present with any findings other than a positive straight leg raising test. Classic presentation includes numbness in a dermatomal distribution corresponding to the level of disc involved, with findings of motor weakness and reflex loss as described below. Herniated discs have different presentations depending on the location as follows:
    • At L4: Pain along the front of the leg; weak extension of the leg at the knee; sensory loss about the knee; loss of knee-jerk reflex
    • At L5: Pain along the side of the leg; weak dorsiflexion of the foot; sensory loss in the web of the big toe; no reflexes lost
    • At S1: Pain along the back of the leg; weak plantar flexion of the foot; sensory loss along the back of the calf and the lateral aspect of the foot; loss of ankle jerk
    • L5 and S1: These nerve roots are involved in approximately 95% of all disc herniations.
  • Spinal stenosis may be present when evidence of degenerative joint disease is present on radiographic studies.
    • Patients with this disease process often complain of progressive pain down the lateral aspect of the leg during ambulation (pseudoclaudication). This pain results from neurologic compression rather than actual arterial insufficiency, which produces true claudication. In cases of spinal stenosis, the straight leg test result is often negative.
    • The stoop test helps distinguish true claudication from pseudoclaudication. Patients with true claudication sit down to rest when pain occurs, while patients with pseudoclaudication attempt to keep walking by stooping or flexing the spine to relieve the stretch on the sciatic nerve.
  • Sacroiliitis usually presents with pain over the involved joints and no peripheral neurologic findings.
  • Osteomyelitis may be subacute or acute.
    • Clinical findings are nonspecific, and the patient may be afebrile on presentation.
    • Classic presentation includes pain on palpation of the vertebral body, elevated sedimentation rate, and complaints of pain out of proportion to physical findings.
    • Patients particularly at risk for development of osteomyelitis include patients who have undergone recent back surgery, intravenous (IV) drug users, patients with immunosuppression, and those with a history of chronic pelvic inflammatory disease (PID).


Please refer to Pathophysiology, which describes specific causes of back pain in detail. Certain clinical clues can help differentiate between causes. Generally, impingement syndromes produce positive straight leg raising tests, whereas pure irritation does not. To assess for a functional disorder as the cause of low back pain, consider the following:

  • Mechanical low back pain is a common complaint in patients with functional disorders. In addition, a functional overlay or component of secondary gain may be present in some patients with true organic pathology. The degree of psychosocial issues affecting the patient’s condition may be assessed by the following:
    • Patient may receive compensation for injury.
    • Patient has pending litigation.
    • Patient dislikes job.
    • Patient has symptoms of depression.
    • Patient caused the accident resulting in back pain.
  • Physical clues that help identify patients with significant functional overlay or component of secondary gain include the following:
    • Findings of nonanatomic motor or sensory loss
    • Nonspecific tenderness or generalized tenderness over the entire back
    • Overly dramatic behavior and loss of positive straight leg raising test when patient is distracted
  • A particularly useful test is to have patients hold their wrists next to their hips and turn their body from side to side. This test gives the illusion that you are testing spinal rotation, but no actual stress is placed on any muscles or ligaments. Any complaint of pain during this maneuver is strongly suggestive of a functional overlay or component of secondary gain in the presentation.

Laboratory Studies

  • Consider performing urinalysis if the problem is not clearly musculoskeletal or an exacerbation of chronic back pain.
  • Perform a complete blood count (CBC) and erythrocyte sedimentation rate (ESR) if the patient is febrile or if an epidural or spinal abscess, or osteomyelitis is suspected. While ESR has moderate specificity, the sensitivity is relatively high in cases of abscess, and it can be used as a screening test.
  • Other laboratory studies are rarely needed unless a disorder other than back pain is strongly suspected.

Imaging Studies

  • Radiography
    • Lumbosacral spine series are expensive and expose the reproductive organs to significant radiation. Annually, 7-8 million such tests are obtained, but most have little value in directing therapy, particularly among adults younger than 50 years.
    • Osteophytes are the most frequently seen abnormality of plain films followed by intervertebral disc space narrowing. Both increase with age. Disc space narrowing appears to be more frequent in women. Disc space narrowing at 2 or more levels is strongly associated with back pain pathology.
    • Unless a history of traumatic injury or systemic illness is present, such films should be obtained only for suspicion of malignancy or infection. Malignant involvement of vertebral bodies can be evident on plain film when as little as 30% of the vertebral body has been replaced.
    • Other indications that suggest the need for radiographic imaging include chronic steroid use and acute onset of pain in patients older than 50 years or in the pediatric age group.
    • The physician may also consider obtaining radiographs in patients whose cases involve (or potentially involve) litigation or for patients seeking compensation.
  • CT and MRI
    • CT and MRI are generally considered the studies of choice for more precise imaging of the vertebrae, paraspinal soft tissues, discs, or spinal cord. CT images cortical bone with higher resolution and can delineate some fractures better than MRI.
    • MRI is generally the preferred imaging modality for detecting disc, cord, or soft tissue abnormalities.
  • Ultrasonography may be useful if the differential diagnosis includes appendicitis, a pathologic pelvic process, or abdominal aneurysm.
  • True emergencies that necessitate imaging include the following:
    • Patients with a history of malignancy and new evidence of nerve entrapment
    • Patients with back pain associated with paralysis or gross muscle weakness
    • Patients with bilateral neurologic deficits associated with bowel or bladder function loss
    • Patients in whom an epidural hematoma or epidural abscess is suspected
    • Postoperative patients with a recent lumbar laminectomy or hip replacement

Improvement occurs in almost all patients within 4-6 weeks, except those with infection, occult malignancy, or systemic illness. If pain fails to significantly improve or resolve in this time frame, imaging is always indicated.

Other Tests

  • Perform the straight leg raising test with the patient in a supine position. Record the response to raising each leg. An approximation of the test may be performed with the patient sitting and each leg straightened at the knee. The examiner should take care to make sure that the quadriceps muscle is relaxed while passively raising the leg to ensure that the sciatic nerve is being adequately stretched during the testing. If the quadriceps is contracted, it will take the pressure off the sciatic nerve and may give a false-negative result.
  • The stoop test helps distinguish true claudication from pseudoclaudication. Patients with true claudication sit down to rest when pain occurs, while patients with pseudoclaudication attempt to keep walking by stooping or flexing the spine to relieve the stretch on the sciatic nerve.

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