[Microtraumatic pathology of the lumbar isthmus: isthmic lysis or spondylolysis].

The authors report the study of a series of 23 partial isthmic lyses which occurred in a young population (15 cases) and in an adult one (8 cases) between 1983 and 1988, in the form of persistent lumbosacral pains. The initial radiological signs, the key to an early diagnosis, are defined: cortical notches more often regarding the lower cortex than the upper one, incomplete fissures reaching the two cortical poles, gradual narrowing of the isthmus. The value of standard radiography is underlined, with the oblique incidences close to the profile regularly ensuring the diagnosis, with the exception of 4 cases out of 23 for which tomography was required. As regards the evolution, the value of the diagnosis of the initial lesions is recalled, giving the hope of a restoration of the posterior inter-articular fractures by a rigid setting (4 months on average). This ability to reconstruct the lumbar isthmus is observed in the young subjects (10 out of 13 immobilizations) but also in the adult subjects (3 reconstructions for 5 immobilizations carried out). These results enable the early detection of prelytic states, in order to administer an suitable treatment resting on the rigid setting of the lumbosacral region, re-education and the control of the risk factors.