[Spondylolisthesis in the growing spine]. / Spondylolisthese im Wachstumsalter.

BACKGROUND: Spondylolisthesis (Greek for sliding vertebra) in children is usually the result of a defect (=lysis) or an elongation of the interarticular portion. The cause can be a congenital dysplasia of the dorsal stabilizing structures or pressure of the facet on the interarticular portion. This is a consequence of lumbar lordosis which is necessary for an upright posture. TREATMENT: The treatment depends on the symptoms and the risk of progression. This is related to the sliding distance, the degree of secondary dysplasia of the vertebral bodies and the sagittal profile, which is considered in the Mac-Thiong classification. For low-grade olistheses, conservative therapy is an option; for a symptomatic lysis without disc degeneration, pars repair should be considered. In higher-grade olistheses, repositioning and spondylodesis are usually recommended. Repositioning improves the fusion rate and sagittal profile, but increases the risk of nerve root damage, so complete repositioning should not be forced.

Interstitial cells of Cajal: crucial for the development of megacolon in human Chagas' disease?

AIM: Megacolon, chronic dilation of a colonic segment,is accompanied by extensive myenteric neuron loss. However, this fails to explain unequivocally the formation of megacolon. We aimed to study further enteric structures that are directly or indirectly involved in colonic motility. METHOD: From surgically removed megacolon segments of seven Chagasic patients, three sets of cryosections from oral, megacolonic and anal zones were immunohistochemically quadruple-stained for smooth-muscle actin (SMA), synaptophysin (SYN, for nerve fibres), S100 (glia) and c-Kit (interstitial cells of Cajal, ICCs). Values of area measurements were related to the appropriate muscle layer areas and these proportions were compared with those of seven non-Chagasic control patients. RESULTS: Whereas nerve and glia profile proportions did not mirror unequivocally the changes of Chagasic colon calibre (nondilation/dilation/nondilation), the proportions of SMA (i.e. muscle tissue density) and c-Kit (i.e. ICC density) did so: they decreased from the oral to the megacolonic segment but increased to the anal zones (muscle tissue density: control 68.3%, oral 54.3%, mega 42.1%, anal 47.6%; ICC-density: control 1.8%, oral 1.1%, mega 0.4, anal 0.8%). CONCLUSION: Of the parameters evaluated, muscle tissue and ICC densities may be involved in the formation of Chagasic megacolon, although the mechanism of destruction cannot be deduced.