Lumbar spondylolysis: a review

Abstract

Spondylolysis is an osseous defect of the pars interarticularis, thought to be a developmental or acquired stress fracture secondary to chronic low-grade trauma. It is encountered most frequently in adolescents, most commonly involving the lower lumbar spine, with particularly high prevalence among athletes involved in certain sports or activities. Spondylolysis can be asymptomatic or can be a cause of spine instability, back pain, and radiculopathy. The biomechanics and pathophysiology of spondylolysis are complex and debated. Imaging is utilized to detect spondylolysis, distinguish acute and active lesions from chronic inactive non-union, help establish prognosis, guide treatment, and to assess bony healing. Radiography with satisfactory technical quality can often demonstrate a pars defect. Multislice CT with multiplanar reformats is the most accurate modality for detecting the bony defect and may also be used for assessment of osseous healing; however, as with radiographs, it is not sensitive for detection of the early edematous stress response without a fracture line and exposes the patient to ionizing radiation. Magnetic resonance (MR) imaging should be used as the primary investigation for adolescents with back pain and suspected stress reactions of the lumbar pars interarticularis. Several imaging pitfalls render MR imaging less sensitive than CT for directly visualizing the pars defects (regional degenerative changes and sclerosis). Nevertheless, the presence of bone marrow edema on fluid-sensitive images is an important early finding that may suggest stress response without a visible fracture line. Moreover, MR is the imaging modality of choice for identifying associated nerve root compression. Single-photon emission computed tomography (SPECT) use is limited by a high rate of false-positive and false-negative results and by considerable ionizing radiation exposure. In this article, we provide a review of the current concepts regarding spondylolysis, its epidemiology, pathogenesis, and general treatment guidelines, as well as a detailed review and discussion of the imaging principles for the diagnosis and follow-up of this condition.

Spondylolytic spondylolisthesis: various imaging features and natural courses

“…In the case of nonunion, fibrous scar and/or fluid may be seen in the gap. The signal intensity of the gap may be inhomogeneous as the result of the mixed fibrous liquid components [1].…”

“…Spino-pelvic parameters, including the sacral slope, pelvic tilt, and pelvic incidence, measured by lateral radiographs of the lumbosacral spine, may also have an important role in the development of spondylolisthesis due to spondylolysis. A high pelvic incidence is a predisposing factor for L5 spondylolisthesis because high pelvic incidence indicates a high sacral slope and/or pelvic tilt, and may increase lumbar lordosis, which contributes to high shear stress to the L5 isthmus, resulting in lysis [1].…”

“…The fifth lumbar vertebra is involved in 95 % of cases and the incidence decreases cephalad. Generally the defect is bridged by fibrous, cartilaginous or osseous tissue, and osseous fusion represents healing [1]. Spondylolisthesis is referred to as a displacement of the vertebra and there are two types, one associated facet tropism has been investigated [12].…”

Frequency of spondylolysis and chronic low back pain in young soccer players

“…[2][3][4] Spondylolysis is a bone defect of the posterior neural arch and in 95% of cases it affects the pars interarticularis of L5. 5,6,9 Its physiopathology has not been explained in detail, but the hypothesis that it is a stress fracture caused by excessive load is widely accepted. 4,10,11 Anatomical and biomechanical changes to the positioning of the sacrum in relation to the ground, the degree of lordosis, occult spina bifida, and family history are other possible factors in the development of this change.…”

“…4,5 In most cases, it presents in an acute and self-limiting form, caused mainly by injuries to the ligaments and paraspinal muscles. The persistence of symptoms in young athletes may suggest other diagnostic hypotheses, especially spondylolysis [5][6][7][8] and degenerative disc disease. [2][3][4] Spondylolysis is a bone defect of the posterior neural arch and in 95% of cases it affects the pars interarticularis of L5.…”