Wilhelm Johannsen Centre for Functional Genome Research, Department of Medical Genetics, Institute of Biochemistry and Genetics, University of Copenhagen, Denmark. MB@IMBG.ku.dk
In the last two to three decades, increasing rates of gastroschisis but not of omphalocele have been reported from different parts of the world. The present study represents a register containing 469 children born with abdominal wall defects based on data retrieved from 20 birth cohorts (1970-89) in three nationwide registries. A tentative estimate of the completeness as regards identification of liveborn and stillborn infants is a minimum of 95% and 90% respectively. All cases were reclassified to 166 cases of gastroschisis, 258 of omphalocele and 16 of gross abdominal wall defect. The average point prevalence at birth of gastroschisis was 1.33 per 10 000 live and stillbirths. During the first decade, an increase in prevalence occurred culminating in 1976, followed by a decrease reaching its initial value in 1983 and then a new increase. Overall, no significant linear trend could be demonstrated for the entire period. The average point prevalence at birth for omphalocele was 2.07 and for gross abdominal wall defect 0.12 per 10 000 live and stillbirths with no significant change in the period. The geographical distribution of gastroschisis and omphalocele showed no difference per county.
The records of an ongoing health surveillance registry that utilizes multiple sources of ascertainment were used to study the incidence rate of congenital malformations of the anterior abdominal wall in live-born children in British Columbia during the period 1964--1978 inclusive. No overall increase in incidence rate of these anomalies was detected during the study period. The estimated live-born incidence rates were: one in 4,175 live births for omphalocoele, one in 12,328 live births for gastroschisis, and one in 29,231 live births for prune belly. The data were analyzed with regard to sex and associated anomalies. Some practical implications regarding assessment of these infants are discussed.
We reviewed 225 cases of amyoplasia, and the association of amyoplasia with gastroschisis and with monozygotic twinning was confirmed. In addition, an apparently increased association of bowel atresia and defects in the muscular layer of the trunk wall with amyoplasia was observed. The association of amyoplasia, monozygotic twinning, and these trunk wall defects strongly suggests that the pathogenesis of amyoplasia is linked to some type of vascular compromise.
A retrospective descriptive study of omphalocele and exstrophic defects of the abdominal wall was carried out in Manitoba to determine the prevalence of these defects, changes in birth incidence with time and their etiologic heterogeneity. The incidence of isolated omphalocele was similar to that reported in other series but the overall incidence of other types of abdominal wall defects was high. Cloacal exstrophy, bladder exstrophy and amnion disruption defects contributed significantly to the number of cases ascertained and emphasized the heterogeneity of abdominal wall defects. There were fluctuations in birth incidence with time with cloacal exstrophy especially apparently being more common in 1980-81. No specific demographic or environmental factors were documented in the cases seen in 1980-81 which could explain the high incidence in these years. Cloacal exstrophy is, however, now appreciated to be much more common than first realized. Studied directed at elucidation of the causes of apparent changes in incidence of malformations such as omphalocele or exstrophic defects will have to take into account both the fluctuations in background incidence of these defects and the considerable diversity in their etiology.
Results of reconstruction of gastroschisis are presented. 27 consecutive patients operated upon during 1971 - 1980 are reviewed: 8 patients with primary closure, 19 patients reconstructed with a staged procedure (silon-pouch). It is concluded that both methods can be used, with low mortality: 1 patient in each group. The use of silon-pouch resulted, however, in a longer period of total parenteral nutrition (46 vs 18 days) and hospital care (8 vs 43 days).
A series of 100 patients with gastroschisis and omphalocele is presented. It is emphasized that gastroschisis generally has a strikingly homogeneous clinical presentation, while the omphalocele has a more heterogeneous clinical presentation, varying from the smallest to the largest, nearly incorrectable type. The main problem in the two groups is the problem of the closure of the defect. In gastroschisis there are, in addition, two problems related to the length of the intestinal tract and the tendency to peritonitis and septicaemia. In omphalocele, however, the major problem is the associated anomalies. The experience from the present material indicates that greater efforts must be used in the future in trying to avoid hypothermia, both during transportation and during operation. Furthermore, greater efforts must be made in closing the abdominal wall defect primarily in both groups of patients. More liberal use of respirator and total parenteral nutrition, mainly by peripheral veins, has obviously contributed to the improvement in our results from 1 60% mortality rate in the first nine-year period to a 37% mortality rate in the last nine-year period in the omphalocele group. Our best results have been obtained during the last 3 years with 2 deaths in the last 12 patients who all were treated by primary closure. In the gastroschisis group a survival rate of 69% in the whole series and of 74% in those who were primarily completely closed must be looked upon as progress in the light of earlier reports of survival rates of 36% to 43%.
