A quantitative study of smooth muscle cells in reflux, obstructed, and triad bladders. A preliminary report;

This quantitative study has shown that the average size of the vesical smooth muscle cells of humans increases with age, whereas the average nuclear size remains constant. In the bladders of six babies with proven outflow obstruction, the cell size was signigicantly increased. In 23 of 25 bladders of infants and children with vesicoureteral reflux there was no apparent hypertrophy, but in two the cells were larger than normal and the micturition cystourethrograms exhibited features which may signify impairment of outflow. In two autopsy bladder specimens of two newborn, triad syndrome babies, there was no hypertrophy of muscle cells, indicating absence of obstruction in fetal life. Three giant bladders associated with rectovesical fistula deformities (two newborn specimens) and dyskinesia of the small and large bowel showed no hypertrophy of muscle cells, indicating that the enlargement was unlikely to be obstructive and appeared to be developmental in origin. Hypertrophy of muscle cells of the bladder indicated obstruction to the outflow, even when the degree of obstruction was mild. Muscle cell size can be measured on full thickness small surgical biopsy specimens prepared as paraffin sections and hence the method can be useful in clinical practice.