F. Sérgio P. Regadas

Prospective Multicenter Trial Comparing Echodefecography With Defecography in the Assessment of Anorectal Dysfunction in Patients With Obstructed Defecation

BACKGROUND: Defecography is the gold standard for assessing functional anorectal disorders but is limited by the need for a specific radiologic environment, exposure of patients to radiation, and inability to show all anatomic structures involved in defecation. Echodefecography is a 3-dimensional dynamic ultrasound technique developed to overcome these limitations. OBJECTIVE: This study was designed to validate the effectiveness of echodefecography compared with defecography in the assessment of anorectal dysfunctions related to obstructed defecation. DESIGN: Multicenter, prospective observational study. PATIENTS: Women with symptoms of obstructed defecation. SETTING: Six centers for colorectal surgery (3 in Brazil, 1 in Texas, 1 in Florida, and 1 in Venezuela). INTERVENTIONS: Defecography was performed after inserting 150 mL of barium paste in the rectum. Echodefecography was performed with a 2050 endoprobe through 3 automatic scans. MAIN OUTCOME MEASURES: The &kgr; statistic was used to assess agreement between echodefecography and defecography in the evaluation of rectocele, intussusception, anismus, and grade III enterocele. RESULTS: Eighty-six women were evaluated: median Wexner constipation score, 13.4 (range, 6–23); median age, 53.4 (range, 26–77) years. Rectocele was identified with substantial agreement between the 2 methods (defecography, 80 patients; echodefecography, 76 patients; &kgr; = 0.61; 95% CI = 0.48–0.73). The 2 techniques demonstrated identical findings in 6 patients without rectocele, and in 9 patients with grade I, 29 with grade II, and 19 patients with grade III rectoceles. Defecography identified rectal intussusception in 42 patients, with echodefecography identifying 37 of these cases, plus 4 additional cases, yielding substantial agreement (&kgr; = 0.79; 95% CI = 0.57–1.0). Intussusception was associated with rectocele in 28 patients for both methods (&kgr; = 0.62; 95% CI = 0.41–0.83). There was substantial agreement for anismus (&kgr; = 0.61; 95% CI = 0.40–0.81) and for rectocele combined with anismus (&kgr; = 0.61; 95% CI = 0.40–0.82). Agreement for grade III enterocele was classified as almost perfect (&kgr; = 0.87; 95% CI = 0.66–1.0). LIMITATIONS: Echodefecography had limited use in identification of grade I and II enteroceles because of the type of probe used. CONCLUSIONS: Echodefecography may be used to assess patients with obstructed defecation, as it is able to detect the same anorectal dysfunctions found by defecography. It is minimally invasive and well tolerated, avoids exposure to radiation, and clearly demonstrates all the anatomic structures involved in defecation.

Imaging atlas of the pelvic floor and anorectal diseases

This chapter should help to clarify the anatomical relationships and complex anorectal topography that can be clearly visualized by modern ultrasound techniques and should be recognized by the pelvic surgeon. The pelvic floor forms the supportive and caudal border of the abdominal cavity. Previous anatomical studies have demonstrated that the pelvic connective tissue can be divided into three compartments: anterior, middle, and posterior. This chapter is dedicated to the posterior compartment and reflects the supportive function of the pelvic floor muscle systems as well as its impact on continence function and defecation.

2- and 3-D Ultrasonography of Endometriosis, Pelvic Cyst, Rectal Solitary Ulcer, Muscle Hypertrophy, Rare Neoplasms

Here we discuss the role of the anorectal two- and three-dimensional ultrasonography in evaluating rarer benign and malignant anorectal and pelvic diseases. This is a useful exam to stage such lesions, identifying their relationship with the rectal wall and sphincter muscles and helping choose the best treatment option.

Two- and Three-dimensional Ultrasonography in Benign and Malignant Rectal Neoplasms

Ultrasound (US) scanning plays an important role in locoregional tumor staging and has been shown to be efficient in detecting parietal invasion and metastasized perirectal lymph nodes. This chapter discusses the role of anorectal US in evaluating the extent of tumor invasion in the rectal wall, sphincter muscles, and perirectal lymph nodes; the extent of tumor invasion following radiotherapy; and detecting early local recurrence in the rectal wall or perirectal lymph nodes. The three-dimensional scanning mode enables the examiner to stage lesions in multiple planes, measure tumor length, and determine the distance between the distal tumor border and the sphincter muscles for comparison with measurements taken after radiotherapy. This is an important aspect to consider when planning surgical resection with or without sphincter saving. In addition, the three-dimensional scanning mode is safer, as it makes it possible to review the images posteriorly, in real time, as required by some lesions.

Two- and Three-dimensional Ultrasonography in Abscess and Anal Fistula

Three-dimensional anorectal ultrasound presents an important role in the evaluation of cryptoglandular disease of the anal canal. It clearly shows the location, extent of the abscess cavity, and relation to the sphincter muscles and rectal wall, making classification possible, which is particularly important for the complex abscess. It is also particularly useful for evaluating anorectal fistulas, as it identifies primary and secondary tracts, internal opening, and adjacent cavities. This information facilitates surgical planning, consequently preventing recurrence and fecal incontinence.

Two- and Three-dimensional Ultrasonography of Anatomic Defects in Fecal Incontinence

Here we discuss the role of endoanal ultrasound (US) scanning in fecal incontinence. Two-dimensional (2-D) US demonstrates precisely the type and extent of muscle injuries in relation to the anal circumference, whereas 3-D scanning shows it in relation to anal canal length. Interpretation of 3-D imaging is simpler, as muscle length can also be measured longitudinally. The exact identification of the injured muscles is important in deciding upon the best therapeutic option. Anal US can also be useful in evaluating the results of surgical repair, identifying adjacent or overlapping muscles, and documenting persisting muscle injury.

Dynamic Two- and Three-dimensional Ultrasonography: Echodefecography

Here we describe a novel dynamic ultrasonography technique — echodefecography — using a 360° two-and three- dimensional transducer with automatic scanning to assess patients with obstructed defecation. The technique is useful to evaluate evacuation disturbances affecting the posterior compartment (anorectocele, intussusception, prolapse, and anismus) and the middle compartment (enterocele). Echodefecography may be used as an alternative method to assess patients with obstructive defecation syndrome, as it has been shown to detect the same anorectal dysfunctions identified by defecography.

Staging and Follow-up of Anal Canal Neoplasms with 2- and 3-D Ultrasonography

Here we discuss the importance of the three-dimensional ultrasonography in evaluating malignant tumor of the anal canal as it allows quantifying the extent of tumor invasion into the sphincter muscles, adjacent tissues, and rectum, identifying lymph nodes as well. This modality is very useful in evaluating chemoradiotherapy response and selecting safe biopsy sites in case of suspicion of early recurrence.

Three-Dimensional Ultrasonography of Pelvic Floor and Anorectal Anatomy

Here we discuss precisely the anatomic configuration of the anal canal and the length and thickness of the anal sphincters using 3D anorectal ultrasonography in both genders, demonstrating the anal canal’s asymmetrical configuration. The rectum and all adjacent pelvic organs are shown in multiple anatomic planes.