Mechanical Back Pain Clinical Presentation

Updated: Aug 27, 2020
  • Author: Debra G Perina, MD; Chief Editor: Trevor John Mills, MD, MPH  more...
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A thorough history and physical examination is paramount to arrive at a diagnosis, and initially imaging is often unnecessary. [6]  Patients most often complain of pain in the lumbosacral area. Determine whether pain is exacerbated by movement or by prolonged sitting or standing; the duration of pain; and whether the pain is relieved by lying down.

Establish if pain was sudden in onset or gradual over days or months, and determine whether 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. Additional signs and symptoms include loss of anal sphincter tone or fecal incontinence, saddle anesthesia, and global or progressive weakness in the lower limbs. [5]

The existence of traditional red flags for occult vertebral fractures, such as advancing age, long-term steroid use, spinal point tenderness, and minor trauma, appear to be relatively poor indicators if used individually. The presence of 2 or more of these should raise the index of suspicion for the clinician. [19]

A history of cancer, unexpected weight loss, immunosuppresion, urinary infection, intravenous drug use, prolonged use of steroids, and/or back pain that does not improve with conservative management suggest a malignancy or infectious cause for the pain. [5]  

Certain clinical clues can help differentiate causes. Generally, impingement syndromes produce positive straight-leg-raising tests, whereas pure irritation does not. 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. [20]  The degree of psychosocial issues [43] 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, and 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.


Physical Examination

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. [21]

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. [22]

Perform an abdominal examination to exclude intra-abdominal pathology.

Men older than 50 years should be given a rectal examination 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 post void 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.

 A pelvic examination should be done 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).