Cost-effectiveness, degree of radiation exposure, and optimum standards of diagnostic sensitivity are the major factors to consider when designing or determining a reasonable screening examination in diagnostic radiology. Among disorders manifesting low back pain, lumbar spondylolysis, a common bony defect of the pars interarticularis of the lumbar spine, is considered to have the highest requirement for oblique view radiography. Currently, oblique views are considered the gold standard for diagnosing pars interarticularis defects in current clinical radiological practice. A typical isthmic spondylolysis is seen as a lucency crossing the pars interarticularis at the neck of the Scotty dog. The idea of a purely congenital etiology has been dismissed since spondylolysis has never been detected in the fetus or the newborn.
Back pain is a common cause of visits to orthopedic surgeons and emergency departments.
These physicians are often the first to order plain X-rays as the initial step in assessing patients with low back pain. Therefore, their diagnoses, decisions on management, and prognoses of these patients depend on or rely on the usefulness and diagnostic yield of the screening exam. We conducted a retrospective study to determine the frequency of detecting a pars defect in a random combination of oblique and lateral lumbar series. Since our goal was to determine the usefulness of oblique views to non-radiologists as a diagnostic tool for low back pain, we used eight radiology residents, from all four years of residency training, to simulate a group of physicians with limited radiological experience, acting upon the interpretation of a screening exam. The oblique and lateral films of 22 spondylolysis cases were subsequently examined by an experienced musculoskeletal radiologist to confirm the presence of a lytic pars defect.