Review Question - QID 215598

Adult Isthmic Spondylolisthesis Etiology Pathophysiology QID: 215598 (OBQ20.187)

QID 215598 (Type "215598" in App Search)

A 37-year-old male presents to your clinic with complaints of severe low back pain of several months duration with numbness that radiates into the dorsum of his left foot and weakness with great toe extension. Straight leg raise testing is negative. He says his pain has worsened over this time period. He denies prior back pain or recent trauma. He also denies any history of systemic symptoms such as fevers or chills. He has no incontinence of bowel or bladder. Figure A demonstrates his lateral lumbar radiograph. Which of the following statements is true regarding this patient's diagnosis?

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Is a result of repetitive hyperflexion exercises

19/1321

Caused by a defect in the pars interarticularis

87%

1144/1321

Most commonly occurs at L4-L5

85/1321

Severity does not correlate with pelvic incidence

17/1321

Progression is more common in adults than adolescents

49/1321

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This case represents a patient with adult isthmic spondylolisthesis, which is caused by a defect in the pars interarticularis.

Spondylolithesis is defined as a forward slip of one vertebral body compared to the one below it. Isthmic spondylolithesis is a specific variant which is caused by a defect in the pars interarticularlis at the affected level. Pars defects are common in activities that require repetitive hyperextension and are thought to occur most often at the L5-S1 level due to the facet orientation being more coronal. Typically, isthmic spondylolithesis leads to radicular symptoms of the exiting nerve root, caused by compression in the foramen adjacent to the pars location. Isthmic spondylolithesis is usually managed non-operatively initially, but may require decompression and instrumented fusion.

Jones et al reviewed adult isthmic spondylolithesis. They discuss how the pain generation in this pathology is unique, as both the pars defect and the spondylolithesis itself can cause pain. They go on to discuss management, stating that most can be treated nonsurgically but those with intractable pain or neurologic deficit should be treated operatively with circumferential fusion.

Floman et al examined the progression of lumbosacral isthmic spondylolithesis in adults who had serial radiographs after diagnosis. They found that 9-30% of slips progressed, between 2 and 20 years after diagnosis. They concluded that a significant number of patients with isthmic spondylolithesis ended up going on to fusion, particularly as associated disc degeneration worsened.

Figure A is a lateral radiograph demonstrates L5-S1 isthmic spondylolithesis, as seen with the pars defect

Incorrect Answers:
Answer 1: Isthmic spondylolithesis is more commonly a result of repetitive hyperextension activities, such as gymnastics.
Answer 3: Isthmic spondylolithesis occurs most commonly at the L5-S1 level, compared to degenerative spondylolithesis, which occurs more at the L4-L5 level.
Answer 4: Increased pelvic incidence has been shown to correlate with the severity of the spondylolithesis.
Answer 5: While progression can occur in adults, it is more common in adolescents.