Which physical findings are characteristic of pars interarticularis injury?

Updated: Jan 22, 2019
  • Author: Gerard A Malanga, MD; Chief Editor: Craig C Young, MD  more...
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Common findings during the physical examination of a patient with spondylolysis may include the following:

  • Upon inspection of the lumbar spine: A patient with LBP resulting from spondylolysis often exhibits a reduced lordotic posture with excessive hamstring tightness.

  • The classically described Phalen-Dickson sign (ie, a knee-flexed, hip-flexed gait) may be demonstrated in patients with spondylolysis. Although this sign is more often seen in those with concomitant spondylolisthesis, it may be present regardless of the degree of vertebral slippage. [26]

  • A gait pattern described as the pelvic waddle has also been described in association with spondylolysis. The hallmark of this gait abnormality includes a stiff-legged gait with a short stride length due to hamstring tightness.

  • The clinician should also note the presence or absence of skin dimpling in the lumbosacral region that may signify the presence of spina bifida occulta, thereby raising the clinical suspicion of spondylolysis.

  • Palpation of the overlying paraspinal region often produces tenderness, and there may be spasm of the paraspinal musculature that causes splinting in acute cases. [3] Take care to identify a possible "step-off" when palpating over the spinous process. This step-off is indicative of concomitant spondylolisthesis, particularly over the L5-S1 level.

  • In assessing lumbar range of motion (ROM), forward flexion is commonly diminished secondary to hamstring tightness. Flexion typically does not increase symptoms, and in many cases, it provides relief. However, extension and rotation commonly cause discomfort for the patient.

  • The preeminent physical examination maneuver thought to most reliably reproduce pain from spondylolysis is the one-legged, hyperextension maneuver, also known as the stork test.

    • The patient is asked to stand on one leg and is brought backward into lumbar extension. Pain due to spondylolysis is thought to be elicited in unilateral lesions by standing on the ipsilateral leg.

    • Although this maneuver is most often described in association with spondylolysis, it stresses other structures besides the pars interarticularis and can therefore be considered to be only suggestive of a pars interarticularis lesion within the context of the clinical picture.

  • The neurologic examination should include assessment of motor strength, sensation, and reflexes. The findings of the neurologic examination should be within normal limits. Typically, radicular findings are absent in patients with isolated spondylolysis.

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