Is the coned lateral lumbosacral junction radiograph necessary for radiological diagnosis?

The lumbar spine radiographs of 400 orthopaedic outpatients were reviewed to determine if the absence of the coned lateral lumbosacral junction radiograph would lead to a loss in diagnostic accuracy. In 84 (21%) patients the antero-posterior and lateral lumbar spine radiographs failed to visualize adequately the lumbosacral junction. In these patients the coned lateral lumbosacral junction radiograph resulted in 17 (4.5%) diagnoses which would otherwise have been missed. The diagnoses were spondylosis (11), spondylolisthesis (3), spondylolysis (1), Paget's disease (1) and infection (1). Absence of the coned lateral lumbosacral radiograph will result in inadequate demonstration of the lumbosacral junction and a loss in diagnostic accuracy.