A. Saifuddin et al., ORIENTATION OF LUMBAR PARS DEFECTS - IMPLICATIONS FOR RADIOLOGICAL DETECTION AND SURGICAL-MANAGEMENT, Journal of bone and joint surgery. British volume, 80B(2), 1998, pp. 208-211
Lateral oblique radiographs are considered important for the identific
ation of spondylolytic lesions, hut these projections will give a clea
r view only when the radiological beam is in the plane of the defect,
We studied the variation in orientation of spondylolytic lesions on CT
scans of 34 patients with 69 defects. There was a wide variation of a
ngle: only 32% of defects were orientated within 15 degrees of the 45
degrees lateral oblique plane. Lateral oblique radiographs should not
he considered as the definitive investigation for spondylolysis. We su
ggest that CT scans with reverse gantry angle are now more appropriate
than oblique radiography for the assessment of spondylolysis. Variati
on in the angle of the defect mag also need consideration when direct
repair is being planned.