Original Article

Techniques in Coloproctology

, Volume 12, Issue 4, pp 323-329

First online:

Effects of age and gender on three-dimensional endoanal ultrasonography measurements: development of normal ranges

  • A. M. KnowlesAffiliated withCentre for Academic Surgery Institute of Cellular and Molecular Science Barts and the London, Queen Mary’s School of Medicine and Dentistry Whitechapel
  • , C. H. KnowlesAffiliated withCentre for Academic Surgery Institute of Cellular and Molecular Science Barts and the London, Queen Mary’s School of Medicine and Dentistry Whitechapel
  • , S. M. ScottAffiliated withCentre for Academic Surgery Institute of Cellular and Molecular Science Barts and the London, Queen Mary’s School of Medicine and Dentistry Whitechapel
  • , P. J. LunnissAffiliated withCentre for Academic Surgery Institute of Cellular and Molecular Science Barts and the London, Queen Mary’s School of Medicine and Dentistry WhitechapelCentre for Academic Surgery 3rd Floor Alexandra Wing, Royal London Hospital Email author 

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Abstract

Background

Faecal incontinence is a common and morbid disorder that is often related to anal sphincter dysfunction. High-frequency, three-dimensional (3-D) endoanal ultrasonography (EAUS) allows greater spatial resolution and longitudinal appreciation of the anal canal than conventional 2-D assessment. A robust normal range of values allowing for age and sex is required for subsequent disease comparison.

Methods

A group of 30 healthy male (n=12) and female (n=18) volunteers (median age, 49 years; range, 31–63 years) underwent 3-D EAUS using a high-frequency 10-MHz transducer. A reconstructed data cube was interrogated to measure anal canal structures in 2-D at high, middle and low levels, and in 3-D for longitudinal measurements.

Results

Men had a significantly longer 3-D external anal sphincter (EAS) and internal anal sphincter (IAS) than women, especially the anterior EAS (mean in men 2.5 cm, mean in women 1.6 cm, p<0.0001). There were no significant differences between the sexes for anal canal length or by 2-D scanning for the thickness of the EAS and IAS. No significant differences were observed between parous and nulliparous women. Age had no significant effect on 3-D length measurements, but 2-D EAUS measurements of the thickness of both the IAS and EAS increased with age significantly (mid canal, p=0.004). On these bases, normal ranges were generated.

Conclusions

Sphincter measurements, enabled by 3-D reconstruction, vary with age and sex. A normal range incorporating these variations has been produced for future data comparison in disease states.

Key words

Anal canal Aging Anal sphincter 3-D endoanal ultrasonography Faecal incontinence