The nature of human waste evacuation: New Insight

Zvarova K1, Rincic Antulov M2, Kobberø H3, Illes Z4, Zvara P5

Research Type

Clinical

Abstract Category

Anatomy / Biomechanics

Abstract 736
Open Discussion ePosters
Scientific Open Discussion Session 108
Saturday 20th September 2025
13:25 - 13:30 (ePoster Station 6)
Exhibition
Physiology Questionnaire Pre-Clinical testing
1. Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark, 2. Department of Surgery, Hospital of Southern Jutland, Aabenraa, Denmark, 3. Department of Urology, Odense University Hospital, Odense, Denmark and Department of Regional Health Research, Denmark, 4. Department of Neurology, Odense University Hospital, Odense, Denmark and Research unit of Neurology, Department of Clinical Research, University of Southern Denmark, Odense, Denmark and Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark, 5. Research unit of Urology, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
Presenter
K

Katarina Zvarova
Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
Links

Abstract

Hypothesis / aims of study 
Lower urinary tract (LUT) and low bowel tract (LBT) are interrelated structures with known interactions that assist their function and play a role in pathophysiology involved in their combined dysfunction.(1) To assess the two systems functional relationship in real-time a sequence of events that take place during the natural process of stool evacuation was studied.
Study design, materials and methods 
Randomly selected adult volunteers were asked to fill out International Consultation on Incontinence (ICIQ)- Lower Urinary Tract Symptoms (LUTS) questionnaire and Wexner fecal incontinence scale and answer the study-specific research question targeting defecation and voiding at the end during the natural process of stool elimination: “Do you void (pass some urine) after defecation”.
Results 
Total of 9 women (aged 30-88, mean 62.55 years) and 3 men (aged 36-63, mean 46.33 years) took part in the study. Prevalence of LUTS increased with age in both genders. LUTS severity increased from none or mild in women 30 to 57 years old (44.4%) to moderate-to-severe in women 62 to 88 years old (55.5%). All men had Wexner score 0. In women a mild liquid and gas fecal incontinence (score<5) was reported (22.2%). All participants (n=12) answered the study-specific research question with “yes”.
Interpretation of results 
The data suggest that voluntary defecation in the adult population occurs simultaneously with voiding, and that the normal defecation event follows voiding-defecating-voiding (VDV) pattern in both women and men. No relation between positive answer to the research question and LUTS, age or mild liquid and gas fecal incontinence was observed.
Concluding message 
Here we report on previously undetected detail in physiology of voiding and defecation. Our finding indicates that a simultaneous LUT and LBT reflex activation is required for neural processing of voluntary defecation. The functional benefit of the two system coactivation and sensory role of voiding at the end of defecation in health, as well as VDV pattern variations in the urogenital and bowel patient population remain unexplored.
Figure 1 Schematic depicting voluntary process of voiding (A) and defecation (B). While voluntary voiding can be initiated independently and even when bladder content is small (2), defection is urge-dependent and occurs simultaneously with voiding in VDV pattern..
References 
  1. Panicker JN, Marcelissen T, von Gontard A, Vrijens D, Abrams P, Wyndaele M. Bladder-bowel interactions: Do we understand pelvic organ cross-sensitization? International Consultation on Incontinence Research Society (ICI-RS) 2018. Neurourol Urodyn. 2019 Dec;38 Suppl 5: S25-S34. doi: 10.1002/nau.24111. PMID: 31821639. DOI: 10.1002/nau.24111
  2. Maggi CA, Meli, A. Do “Conscious” and “Reflex” MicturitionHave a Separate Sensory Input? Implications for Clinical Urodynamics. Neurourol Urodyn. 1986; 5:563-71. https://doi.org/10.1002/nau.1930050607
Disclosures
Funding Odense University Hospital Research Pool Clinical Trial Yes Public Registry No RCT No Subjects Human Ethics Committee SDU Research Ethics Committee (RECID538) Helsinki Yes Informed Consent Yes
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