A 68-year-old woman reports low back pain and heaviness in both legs after walking 200 metres, relieved by sitting and leaning forward on a shopping trolley. Lateral radiographs show forward slip of L4 on L5 with normal, intact pars interarticularis. Which statement is correct regarding this condition?
- A It results from a fatigue fracture of the pars interarticularis
- B Symptoms are characteristically relieved by extension exercises
- C L4-L5 is the most commonly affected level, and facet joint arthrosis allows the slip despite an intact neural arch ✓
- D It most commonly occurs at L5-S1 in adolescent athletes
Correct answer: C. L4-L5 is the most commonly affected level, and facet joint arthrosis allows the slip despite an intact neural arch
Explanation
Degenerative spondylolisthesis arises from facet joint and disc degeneration permitting subluxation with an intact neural arch, and it affects L4-L5 most often, typically in women over 60. Symptoms reflect central and lateral recess stenosis, giving neurogenic claudication eased by flexion, which opens the canal and foramina. Isthmic spondylolisthesis, caused by a pars defect, preferentially affects L5-S1 and is associated with adolescent athletes in hyperextension sports.
Reference: Apley's System of Orthopaedics and Fractures, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.