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Adaptation of the rectal wall to distension in children with constipation
M Bouchoucha1, J P Jais, P Arhan
1Laboratoire de physiologie digestive, Hôpital Laënnec, Paris, France.
Insights
Children with constipation show altered rectal wall mechanics, specifically in the reduced relaxation function, indicating impaired smooth muscle function. This new analysis method using rectal balloon distension is effective for diagnosing chronic constipation in pediatric patients.
Area of Science:
- Pediatric Gastroenterology
- Biomechanical Engineering
- Digestive Physiology
Background:
- Chronic constipation affects a significant number of children, impacting their quality of life.
- Understanding the underlying mechanical properties of the rectal wall is crucial for diagnosing and managing constipation.
Purpose of the Study:
- To investigate changes in the tension-length relationship of digestive smooth muscle in pediatric constipation.
- To evaluate a novel method for analyzing rectal wall mechanical properties.
Main Methods:
- A case-control study involving 30 children with constipation and 30 controls.
- Rectal wall distension using an air-inflated balloon to determine in vivo pressure-volume curves.
- Application of the quasilinear viscoelasticity law for data analysis.
Main Results:
- The quasilinear viscoelastic law effectively characterized rectal wall mechanics in both groups.
- Elastic response of the rectal wall was comparable between constipated children and controls.
- A significant difference was observed in the reduced relaxation function, with an absence of an asymptotic value in constipated children.
Conclusions:
- The proposed method of rectal balloon distension and viscoelastic analysis is a valuable tool for assessing chronic constipation in children.
- Altered rectal wall viscoelastic properties are associated with pediatric constipation.
Objective:
To determine whether there is significant change in the tension-length relationship of the digestive smooth-muscle mechanical function in constipation in children and to examine a new method of analysis of the mechanical properties of the rectal wall.
Design:
Case-control study.
Participants:
Thirty children with constipation and 30 control children who did not have constipation.
Intervention:
Rapid distension of the rectal wall by inflation of a rectal balloon with air.
Main Outcome Measures:
The in vivo rectal pressure-volume P[t,V] curve was determined according to the quasilinear viscoelasticity law. The recorded pressure was defined as the product of 2 functions: the elastic response P0[V] and the reduced relaxation function G[t], a normalized function of time such that P[t,V] = P0[V] x G[t]. Analysis of variance with repeated measures and modelling (linear for P0[V] and exponential plus constant term for G[t] were used for data analysis.
Results:
The quasilinear viscoelastic law can be applied to the in vivo determination of the mechanical properties of the rectal wall in controls and in children with constipation. The elastic response was similar in the 2 groups. The reduced relaxation function was significantly different between the 2 groups, with the absence of an asymptotic value in the group with constipation (p < 0.01).
Conclusion:
Distension of the rectal wall with the use of an air-inflated balloon, with this type of interpretation according to the viscoelastic law, is useful in the analysis of chronic constipation.