新生児,とくに低出生体重児および早産児における直腸肛門機能の成熟過程に関する臨床的研究

抄録

Anorectal manometry was carried out in 57 newborn infants using an infused side-opening catheter. Twenty-eight babies were preterm (gestational age less than 37 weeks) and 28 low birth weight (birth weight less than 2,500gm). The examination was carried out 100 times between 8 hours and 43 days of age. Histometry of the intramural ganglion cells of rectum was also carried out in 11 atitopsied cases, of which 5 were preterm infants. The results of the present studies disclosed that: 1. Anal canal pressure is low in new born infants within 3 days after birth, but there is no correlation between anal canal or rectal pressure and total age (gestational age plus age after birth in weeks). Length of the anal canal and its frequencies of basal rhythmic contraction increase with the advance of total age and body weight at the time of examination. There is no correlation, however, between the length of the anal canal or its frequencies of basal rhythmic contraction and the age in weeks after birth. 2. Rectoanal reflex was positive at the first examination in 53 of 57 cases. Rectoanal reflex was, however, negative or atypical at the first examination in 4 cases. Typical rectoanal reflex appeared at the second or third examination in all these 4 cases. Rectoanal reflex was positive in all 38 examinations carried out in those of which the total age was over 37 weeks and body weight was over 2,500gm. On the other hand, the reflex was negative or atypical in 5 of 41 examinations carried out in those of which the total age was under 36 weeks, or in 5 of 58 examinations carried out in those of which body weight was under 2,500gm. 3. The mean diameter of nuclei of ganglion cells in intramural plexus in 3 cases whose total age was over 41 weeks was significantly larger than in 4 cases who was below 32 weeks. The mean diameter of nuclei of ganglion cells was variable in 4 cases of which total age was between 33 and 40.