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. 2015 Apr;26(4):511-7.
doi: 10.1007/s00192-014-2524-5. Epub 2014 Oct 25.

Anal sphincter complex: 2D and 3D endoanal and translabial ultrasound measurement variation in normal postpartum measurements

Kate V Meriwether  1 , Rebecca J Hall, Lawrence M Leeman, Laura Migliaccio, Clifford Qualls, Rebecca G Rogers
Affiliations

Anal sphincter complex: 2D and 3D endoanal and translabial ultrasound measurement variation in normal postpartum measurements

Kate V Meriwether et al. Int Urogynecol J. 2015 Apr.

Abstract

Introduction and hypothesis: Women may experience anal sphincter anatomy changes after vaginal birth (VB) or Cesarean delivery (CD). Therefore, accurate and acceptable imaging options to evaluate the anal sphincter complex (ASC) are needed. ASC measurements may differ between translabial (TLUS) and endoanal (EAUS) ultrasound imaging and between 2D and 3D US. The objective of this analysis was to describe measurement variation between these modalities.

Methods: Primiparous women underwent 2D and 3D TLUS imaging of the ASC 6 months after VB or CD. A subset of women also underwent EAUS measurements. Measurements included internal anal sphincter (IAS) thickness at proximal, mid, and distal levels and the external anal sphincter (EAS) at 3, 6, 9, and 12 o'clock positions, as well as bilateral thickness of the pubovisceralis muscle (PVM).

Results: There were 433 women presenting for US: 423 had TLUS and 64 had both TLUS and EAUS of the ASC. All IAS measurements were significantly thicker on TLUS than EAUS (all p < 0.01), while EAS measurements were significantly thicker on EAUS (p < 0.01). PVM measurements with 3D or 2D imaging were similar (p > 0.20). On both TLUS and EAUS, there were multiple sites where significant asymmetry existed in left versus right measurements.

Conclusions: US modality used to image the ASC introduces small but significant changes in measurements, and the direction of the bias depends on the muscle and location being imaged.

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Conflict of interest statement

Conflict of Interest Disclosure Statement:

KV Meriwether: No conflicts of interest to disclose

RJ Hall: No conflicts of interest to disclose

LM Leeman: No conflicts of interest to disclose

L Migliaccio: No conflicts of interest to disclose

C Qualls: No conflicts of interest to disclose

RG Rogers: Chair DSMB for the Transform trial sponsored by American Medical Systems

Figures

Figure 1
Figure 1
Images of transverse views (above) and sagittal views (below) with center reference point at each of the three levels of the anal sphincter complex (ASC): proximal, mid, and distal.
Figure 2
Figure 2
Endoanal (left) and translabial (right) transverse ultrasound images of the distal anal sphincter complex, with the external anal sphincter (EAS) and internal anal sphincter (IAS) indicated by the arrows.
Figure 3
Figure 3
Endoanal (left) and translabial (right) transverse ultrasound images of the mid-level anal sphincter complex, with the internal anal sphincter (IAS) and pubovisceralis muscle (PVM) indicated by the arrows.
See this image and copyright information in PMC

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