Is dynamic two-dimensional anal ultrasonography useful in the assessment of anismus? A comparison with manometry

Abstract

-Context -Anismus is a prevalent functional cause of outlet delay. It is characterized by symptoms of obstructed defecation associated with paradoxical contraction of the pelvic floor muscles. Objective -To evaluate the ability of two dimensional anal ultrasonography to identify anismus patients with paradoxical contraction or normal relaxation, comparing findings with manometric measurements. Methods -Forty-nine women presenting with outlet delay and a mean validated Wexner constipation score of 13.5 were included in a prospective study. Following screening with anal manometry, the patients were assigned to one of two groups: G-I -with normal relaxation and G-II -patients with anismus. Dynamic anorectal ultrasonography was used to quantifier the movement of the puborectalis muscle and to measure changes in the angle between two converging lines drawn from the 3 o'clock and the 9 o'clock positions of the endoprobe circumference to the internal border of the puborectalis muscle. The angle decreases during straining in patients with normal relaxation, but increases in patients with anismus. The agreement between the two techniques was verified with the Kappa index. Results -In manometry, during straining the anal canal pressure decreased by 41.3% in G-I and increased by 168.6% in G-II, indicating a diagnosis of anismus for the second group. In US, during straining, the angle produced by the movement of the puborectalis muscle decreased from 63 ± 1.31 to 58 ± 1.509 degrees (P = 0.0135) in 23 of the 30 patients in G-I, indicating normal relaxation, and increased from 66 ± 0.972 to 72 ± 0.897 degrees (P = 0.0001) in 16 of the 19 patients in G-II, indicating anismus. The index of agreement between manometry and two dimensional anal ultrasonography was moderate: 77% (23/30) for G-I and 84% (16/19) for G-II. Conclusion -Two-dimensional dynamic anal ultrasonography showed similar results previously suggested by anal manometry at identifying patients with normal relaxation or paradoxical contraction.

Diagnostic testing for dyssynergic defecation in chronic constipation: meta‐analysis

“…Four studies evaluated concurrent positivity of US and ARM. These were conducted by three groups, all in surgical departments, one in Brazil and two in Europe and included a total of 279 patients. Concurrent positivity for US among those with positive ARM ranged from 68.4% to 88.6% and the median prevalence of combined positivity (positive on both tests) was 37.6% (range 9.3–46.4).…”

“…In the three studies that compared defecography with US, agreement was high with 87.5–91.7% of patients positive by defecography having the corresponding findings on US as well (concurrent positive US). These evaluated 158 patients and were conducted by two groups from surgical departments; one in Europe, one in Brazil …”

Valsalva versus straining: There is a distinct difference in resulting bladder neck and puborectalis muscle position

“…For these examinations it is assumed that the pelvic floor is relaxed. However, it has been shown that during Valsalva or straining, up to two thirds of women contract the pelvic floor . Activation of the pelvic floor muscle (PFM) measured during perineal ultrasound or with EMG is common and has long been accepted as an effect during an increase in intra‐abdominal pressure .…”

Anismus, Physiology, Radiology: Is It Time for Some Pragmatism? A Comparative Study of Radiological and Anorectal Physiology Findings in Patients With Anismus

“…The term Anismus, coined by Preston and Lennard-Jones in 1985 [1], defines a functional disorder with symptoms of obstruction and paradoxical movements of the pelvic floor muscles [2] (puborectalis and external anal sphincter muscles [3]). It has also been defined as an inappropriate contraction or inadequate relaxation of the pelvic floor muscle during defecation [45].…”

“…Dynamic magnetic resonance imaging (MRI) of the pelvis provides the additional advantage of not having to use any ionizing radiations and still provides free selection of planes, remarkable soft tissue imaging, and good temporal resolution: in such settings, anismus has been defined as a failure of anorectal angle opening during straining [13] or a prolonged attempted defecation with incomplete evacuation [6]. Two-dimensional (2D) ultrasonography (US) and dynamic three-dimensional anorectal US [14] are being introduced, but the agreement between 2D echography and manometry is moderate [215]. While biofeedback has been shown to yield positive results in the treatment of anismus [1617], a consistent discrepancy exists between the diagnosis criteria and the methodologies that should be involved.…”