Assessment of third degree tears using three-dimensional anal endosonography with combined anal manometry: a novel technique

Correlation of anorectal symptoms and endoanal ultrasound findings after obstetric anal sphincter injuries (OASIS)

INTRODUCTION

Obstetric anal sphincter injuries (OASIS) predispose to development of anorectal symptoms that affect women's quality of life.

METHODS

A retrospective cohort study was conducted for all women with singleton vaginal deliveries who had a primary OASIS repair and attended the Postpartum Perineal Clinic between July 1st 2017 and December 31st 2020. This study was approved by the Research Ethics Board. The purpose of this study was (1) to determine correlation between endoanal ultrasound (EAUS) findings and anorectal symptoms quantified by the St. Mark's Incontinence Score (SMIS), (2) to determine the incidence of residual anal sphincter defects, and (3) to determine the rate of clinical overdiagnosis of OASIS. Pearson correlation coefficient was used to assess correlation between anorectal symptoms and EAUS findings.

RESULTS

A total of 247 participants with clinical diagnosis of OASIS met the inclusion criteria. A 3rd-degree tear was identified in 126 (51.0%) and 4th-degree tear was identified in 30 (12.1%) participants. In participants with sonographic evidence of OASIS, there was a statistically significant weak positive correlation between the size of residual defect and SMIS for both external anal sphincter (EAS) (r = .3723, p < .0001) and internal anal sphincter (IAS) (r = .3122, p = .0180). Residual defect in the anorectal sphincter of greater than 1 hour (> 30°) in width was present in 64.3% participants with 3rd-degree tear and 86.7% participants with 4th-degree tear. The rate of overdiagnosis was 36.8%.

CONCLUSION

The size of residual defect of EAS and IAS has a weak positive correlation with anorectal symptoms, emphasizing the importance of EAUS for counselling regarding mode of subsequent delivery.

Implementation of Episcissors-60 for Prevention of Obstetric Anal Sphincter Injuries (OASIS) in a Centre with Low Episiotomy Rates

OBJECTIVE

The purpose of this study was to determine whether introduction of Episcissors-60 into a labour and birth unit would decrease the incidence of Obstetric Anal Sphincter Injuries (OASIS).

METHODS

A before-and-after quality improvement study was conducted between April 1, 2020 and March 31, 2021. All patients who had a vaginal delivery were included in this study. All healthcare providers who perform vaginal deliveries were offered an educational session. Episcissors-60 were then introduced into a labour and birth unit. The primary outcome measure was the change in incidence of OASIS before and after introduction of Episcissors-60. Secondary outcome measures were episiotomy rates before and after introduction of Episcissors-60, device-related adverse events, and provider satisfaction and feedback. Data was analyzed using chi-square tests, independent t-tests, and Mann-Whitney tests.

RESULTS

A total of 1383 vaginal deliveries occurred prior and 1254 vaginal deliveries after introduction of Episcissors-60. There was a decrease in the total OASIS rate from 7.37% of all vaginal deliveries prior to 5.37% after introduction of Episcissors-60 (P = .037). The episiotomy rate was 11.42% prior to and 9.97% after introduction of Episcissors-60 (P = .228). OASIS rate in women who had an episiotomy was 12.02% before and 13.60% after introduction of Episcissors-60 (P = .421).

CONCLUSION

Although introduction of Episcissors-60 was associated with a statistically significant decrease in total OASIS rate, there was no difference in OASIS rates within the subgroup that received an episiotomy. Therefore, reduction in the total OASIS rate in this study cannot be attributed to the use of Episcissors-60.

When to assess residual anal sphincter defect after OASI by ultrasound

OBJECTIVES

Obstetrical anal sphincter injuries (OASIS) are complications of vaginal delivery. Unrepaired anal sphincter after delivery increases the risk of anal incontinence. The aim of our study is to search for residual defect after OASI repair by 4D introital ultrasound (US). We hypothesised that imaging prior to hospital discharge would show the same number of defects as assessment at 3 months.

STUDY DESIGN

This is a retrospective analysis of 138 patients with immediate repair after OASIS. Since 2009, we have been routinely inviting all our patients with OASIS to the perineal clinic for postoperative follow-up. We scheduled the first visit before discharge from hospital and followed up with a second visit after three months. During both visits, patients underwent transperineal 4D ultrasound examination. We provided examination while at rest and during contraction; volumes were saved for further evaluation.

RESULTS

Eighty-one patients (58.7%) completed both exams and were included in the analysis. Residual external anal sphincter defect was found in 17.3% at the first visit versus 13.6% at the second (delayed) visit. We were not able to assess the sphincter in 9.9% at early versus none in the delayed examination. In 9.9%, the residual defect was not confirmed by the second examination, and in 4.9% the residual defect was missed by the first examination.

CONCLUSIONS

In conclusion, we have found that a 3 month scan yields a smaller number of defects than a scan before discharge.

Residual Defects of the Anal Sphincter Complex Following Primary Repair of Obstetrical Anal Sphincter Injuries at a Large Canadian Obstetrical Centre

OBJECTIVES

To determine the rates of residual anal sphincter defect following primary repair of obstetrical anal sphincter injury (OASIS), and to assess symptomatology in these patients.

METHODS

A retrospective observational study of patients who underwent primary repair of an OASIS sustained at Mount Sinai Hospital from January 2016 to June 2017. Records were reviewed for demographic and obstetrical data, symptoms of anal incontinence (AI), and the results of endoanal ultrasonography (EA-US).

RESULTS

One hundred and one women sustained an OASIS during the study period, of whom 53 had EA-US performed at Mount Sinai Hospital; 4 women were excluded from this analysis. There were 42 third-degree tears and 7 fourth-degree tears. EA-US revealed residual defects in 22 patients with third-degree tears and 5 patients with fourth-degree tears (52% vs. 71%; P = 0.44).  Twelve patients with third-degree tears and 4 patients with fourth-degree tears reported AI (29% vs. 57%; P = 0.20). EA-US revealed no evidence of a tear in 14 patients clinically diagnosed with third-degree tears and 1 patient clinically diagnosed with a fourth-degree tear (33% vs. 14%).

CONCLUSION

These data demonstrate deficiencies in diagnosis and repair of OASIS. Continued training for health care providers on identification and effective repair of OASIS may improve outcomes for women who experience this complication.

Overdiagnosis and rising rate of obstetric anal sphincter injuries (OASIS): time for reappraisal

OBJECTIVES

To determine the accuracy of clinical diagnosis of obstetric anal sphincter injuries (OASIS) using three-dimensional (3D) endoanal ultrasound (EA-US) and to compare symptoms and anal manometry measurements between women with anal sphincters adequately repaired and those with persistent anal sphincter defects.

METHODS

The EA-US images of women with clinically diagnosed and repaired OASIS, defined as third- or fourth-degree perineal tear, who attended the perineal clinic at Croydon University Hospital over a 10-year period (2003-2013) were reanalyzed by a single expert blind to symptoms and the results of clinical examination. St Mark's Incontinence Scores (SMIS) and anal manometry measurements were obtained and compared between women with an intact anal sphincter and those with an anal sphincter scar and between those with an intact anal sphincter and those with a defect. Anal manometry measurements were compared between women with an external anal sphincter (EAS) defect and those with an internal anal sphincter (IAS) defect.

RESULTS

The images of 908 women were reanalyzed. No evidence of OASIS was found in 64 (7.0%) women, an EAS scar alone was detected in 520 (57.3%) and an anal sphincter defect in 324 (35.7%). Of the 324 women with a defect, 112 had an EAS defect, 90 had an IAS defect and 122 had a combined IAS and EAS defect. SMIS results were significantly higher in women with an anal sphincter defect compared with those with no evidence of OASIS (P = 0.018), but there was no significant difference in scores between women with an intact sphincter and those with an EAS scar only. Women with a defect had a significantly lower maximum resting pressure (median (range), 44 (8-106) vs 55 (29-86) mmHg; P < 0.001) and maximum squeeze pressure (median (range), 74 (23-180) vs 103 (44-185) mmHg; P < 0.001) compared with those in the intact group. Similar, but less marked, differences were observed in women with an EAS scar compared with those who had an intact anal sphincter. The anal length was significantly shorter in women with a defect compared with those in the intact group (median (range), 20 (10-40) vs 25 (10-40) mm; P = 0.003).

CONCLUSIONS

Seven percent of women with a clinical diagnosis of OASIS were wrongly diagnosed. We believe that this rate may differ from that of other units but training methods and competency assessment tools for the diagnosis and repair of OASIS need urgent reappraisal. The role of EA-US in the immediate postpartum period needs further evaluation as the accurate interpretation of the images is dependent on the expertise of the staff involved. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Usefulness of anorectal and endovaginal 3D ultrasound in the evaluation of sphincter and pubovisceral muscle defects using a new scoring system in women with fecal incontinence after vaginal delivery

PURPOSE

This study aims to evaluate pubovisceral muscle and anal sphincter defects in women with previous vaginal delivery and fecal incontinence and to correlate the findings with the severity of symptoms using the combined anorectal and endovaginal 3D ultrasonography with a new ultrasound scoring system.

METHODS

Consecutive female patients with previous vaginal delivery and fecal incontinence symptoms were screened. Fecal incontinence was assessed with the Cleveland Clinic Florida fecal incontinence scale, and the extent of defects was assessed by an ultrasound score based on results of anorectal and endovaginal 3D ultrasound. Fecal incontinence was assessed with the Cleveland Clinic Florida fecal incontinence scale.

RESULTS

Of 84 women with previous vaginal delivery and fecal incontinence, 21 (25%) had intact pubovisceral muscles and anal sphincters; 63 (75%) had a pubovisceral muscle or anal sphincter defect, or both. Twenty-eight (33%) had a pubovisceral muscle defect [23% with an external anal sphincter (EAS) defect or combined EAS/internal anal sphincter defects; 11% with intact anal sphincters]. Thirty-five (42%) had intact pubovisceral muscles and an anal sphincter defect. Compared with women with intact pubovisceral muscles/anal sphincter defects, patients with pubovisceral muscle defects had significantly higher incontinence scores and significantly higher ultrasound scores indicating more extensive defects. Incontinence symptoms correlated positively with the ultrasound score, measurements of sphincter defects, and area of the levator hiatus.

CONCLUSIONS

Evaluation of both pubovisceral muscles and anal sphincters is important to identify defects and determine treatment for women with fecal incontinence after vaginal delivery. The severity of fecal incontinence symptoms is significantly related to the extent of defects of the pubovisceral muscles and anal sphincters.

DO CHANGES IN ANAL SPHINCTER ANATOMY CORRELATE WITH ANAL FUNCTION IN WOMEN WITH A HISTORY OF VAGINAL DELIVERY?

Objectives To evaluate anal sphincter anatomy using three-dimensional ultrasonography (3-DAUS) in incontinent women with vaginal delivery, correlate anatomical findings with symptoms of fecal incontinence and determine the effect of vaginal delivery on anal canal anatomy and function. Methods Female with fecal incontinence and vaginal delivery were assessed with Wexner’s score, manometry, and 3DAUS. A control group comprising asymptomatic nulliparous was included. Anal pressure, the angle of the defect and length of the external anal sphincter (EAS), the anterior and posterior internal anal sphincter (IAS), the EAS + puborectal and the gap were measured and correlated with score. Results Of the 62, 49 had fecal incontinence and 13 were asymptomatic. Twenty five had EAS defects, 8 had combined EAS+IAS defects, 16 had intact sphincters and continence scores were similar. Subjects with sphincter defects had a shorter anterior EAS, IAS and longer gap than women without defects. Those with a vaginal delivery and intact sphincters had a shorter anterior EAS and longer gap than nulliparous. We found correlations between resting pressure and anterior EAS and IAS length in patients with defects. Conclusions Avaliar a anatomia do esfíncter anal usando ultra-sonografia tridimensional (3D-US) em mulheres incontinentes com parto vaginal, correlacionar os achados anatômicos com sintomas de incontinência fecal e, determinar o efeito do parto vaginal sobre a anatomia e função do canal anal.

State of the art: an integrated approach to pelvic floor ultrasonography

Surgical management of pelvic floor disorders depends on a comprehensive understanding of the structural integrity and function of the pelvic floor. For visualizing this region, ultrasonography has emerged as a procedure that is relatively easy to perform, cost-effective and widely available. In this review, pelvic floor ultrasonography, including two-dimensional (2D), three-dimensional (3D) and 4D imaging as well as transvaginal, endoanal and transperineal techniques, is discussed from a global and multicompartmental perspective, rather than using a compartmentalized approach. The role of the different sonographic modalities in the major disorders of the pelvic floor-urinary and fecal incontinence, pelvic organ prolapse and obstructed defecation syndrome-is evaluated critically.

Three-dimensional endoanal ultrasonography of external anal sphincter defects in patients with faecal incontinence: correlation with symptoms and manometry

AIM

Anal sphincter anatomy on two-dimensional endoanal -ultrasonography (EUS) does not always correlate with the clinical data. The purpose of this study was to determine whether three-dimensional (3D) measurements yield a better correlation.

METHOD

The study group included consecutive patients who underwent 3D EUS for faecal incontinence over a 2-year period. The medical charts were reviewed for Cleveland Clinic Foundation Fecal Incontinence (CCF-FI) score and manometric pressures. Endoanal ultrasonographic images were reviewed for the presence of an external anal sphincter (EAS) defect and its extent, as determined by the radial angle, length in the sagittal plane and percentage volume deficit. Correlational analyses were performed between the clinical and imaging data.

RESULTS

Sixty-one patients of median age 53 years (range 15-82) were evaluated. Thirty-two patients had either a complete (17) or partial (15) EAS defect, and 29 patients had an intact sphincter. The CCF-FI scores were similar in patients with and without an EAS defect (12.5 ± 5.6 and 11.4 ± 5.5, respectively). The intact-sphincter group had a significantly greater EAS length (3 ± 0.4 vs 2 ± 0.62 cm, P = 0.02) and higher mean maximal squeeze pressure (MMSP; 99.7 ± 52.6 vs 66.9 ± 52.9 mmHg, P = 0.009). There were no statistically significant correlations between MMSP, CCF-FI score and EAS status on 3D EUS. Mean percentage volume of the defect was similar in patients with complete and partial tears (14.5 ± 5.5 and 17.5 ± 7.2%, P = 0.25) and showed no correlation with physiological tests or symptom scores.

CONCLUSION

Improvements in external anal sphincter imaging have not yielded a better association with the clinical findings. The lack of clinical differences between patients with different EAS tears may reflect their similar volumetric defects.

Three-dimensional endoanal ultrasonography in daily proctological practice

Three-dimensional endoanal ultrasonography (3D-EAUS) provides unequalled quality in terms of the anatomical image of the anal canal and sphincter complex. In less than one minute it produces a three-dimensional "cube" that can be manipulated in all spatial dimensions, then archived. In just a few years it has become a new gold standard exploration in proctology. In addition to image quality, 3D-EAUS has the advantage of being easily and rapidly performed, well-tolerated and moderate in cost. For anal incontinence, 3D-EAUS contributes to the identification of sphincter defects. The anatomy of the sphincters can be evaluated spatially. Simple scoring systems with good reproducibility and readily applicable in routine practice can be used to evaluate the "damaged" sphincter volume. For the management of anoperineal suppurations, 3D-EAUS provides information on the fistulous track(s) and on potential collections. These data are crucial as the choice of treatment and its efficacy depend on accurate topographic assessment of the suppuration and the state of the sphincter apparatus.

The advantages of volume rendering in three-dimensional endosonography of the anorectum

Anorectal diseases require imaging for proper case management. At present, endoanal ultrasonography and endorectal ultrasonography have become important parts of diagnostic workup of patients with fecal incontinence, perianal fistulas, and rectal cancer and provides sufficient information for clinical decision-making in many cases. However, with the currently available ultrasonographic equipment and techniques, a good deal of relevant information may remain hidden. The advent of high-resolution three-dimensional endoluminal ultrasound, constructed from a synthesis of standard two-dimensional cross-sectional images, and of "Volume Render Mode," a technique to analyze information inside a three-dimensional volume by digitally enhancing individual voxels, promises to revolutionize diagnosis of pelvic floor disorders. By use of the different postprocessing display parameters, the volume-rendered image provides better visualization performance when there are not large differences in the signal levels of pathologic structures compared with surrounding tissues. The anatomic structures in the pelvis, the axial and longitudinal extension of anal sphincter defects, the anatomy of the fistulous tract in complex perianal sepsis, and the presence of slight or massive submucosal invasion in early rectal cancer may be imaged in greater detail. This additional information will bring an improvement for both planning and conduct of surgical procedures.

The current role of imaging techniques in faecal incontinence

Faecal incontinence is a common multifactorial disorder. Major causes of faecal incontinence are related to vaginal delivery and prior anorectal surgery. In addition to medical history and physical examination, several anorectal functional tests and imaging techniques can be used to assess the underlying pathophysiology and to guide treatment planning in faecal incontinent patients. Anorectal functional tests provide functional information, but the potential strength comes from combining test results. Imaging techniques, including defecography, endoanal sonography, and magnetic resonance (MR) imaging, provide structural information about the anorectal region with a direct clinical impact. The major role of imaging techniques in faecal incontinence is visualising the structural and functional integrity of the anal sphincter complex. Both two-dimensional endoanal sonography and endoanal MR imaging are accurate tools to depict anal sphincter defects. The major advantage of endoanal MR imaging is the accurate demonstration of external anal sphincter atrophy. Recent studies have suggested that external phased array MR imaging and three-dimensional endoanal sonography are also valuable tools in the diagnostic work up of faecal incontinence. Decisions about the preferred technique will mainly be determined by availability and local expertise. This article demonstrates the current role of tests, predominantly imaging tests, in the diagnostic work up of faecal incontinence.

Integrity of the anal sphincters after pouch-anal anastomosis: evaluation with three-dimensional endoanal ultrasonography

PURPOSE

The aim of the present study was to assess the integrity of the anal sphincters after handsewn pouch-anal anastomosis performed with the help of a Scott retractor. For this purpose the anal sphincters were visualized with three-dimensional endoanal ultrasonography.

METHODS

Patients undergoing a colonic pouch-anal anastomosis or an ileal pouch-anal anastomosis were included. Before and six months after the procedure, the length and volume of both sphincters were assessed with three-dimensional endoanal ultrasonography, and anal manometry was performed. Continence scores were determined using the Fecal Incontinence Severity Index (FISI).

RESULTS

Fifteen patients with a colonic pouch and 13 patients with an ileal pouch were examined. Six months after the procedure, three-dimensional endoanal ultrasonography showed significant alterations of the internal anal sphincter in eight patients with a colonic pouch-anal anastomosis (53 percent) and in eight patients with an ileal pouch-anal anastomosis (62 percent). These alterations were characterized by asymmetry or thinning. No defects were seen in the colonic pouch group, but, in two patients with an ileal pouch, a small defect in the internal anal sphincter was found. A decrease in internal anal sphincter volume was seen only in patients with a colonic pouch-anal anastomosis (P = 0.009). In both groups the length of the internal anal sphincter and the length, thickness, and volume of the external anal sphincter remained the same. After the procedure a reduction of maximum anal resting pressure was found in both groups (colonic pouch: P < 0.001, ileal pouch: P = 0.001). Maximum anal squeeze pressure was reduced in only patients with an ileal pouch-anal anastomosis (P = 0.006). The observed alterations of the internal anal sphincter and the manometric findings showed no correlation with the postoperative Fecal Incontinence Severity Index scores.

CONCLUSION

Handsewn pouch-anal anastomosis, performed with the help of a Scott retractor, only rarely leads to internal anal sphincter defects, but three-dimensional endoanal ultrasonography shows alterations of the internal anal sphincter in 57 percent of the patients. No correlation was observed between these alterations and the functional outcome.

Three-dimensional anal endosonography may improve diagnostic confidence of detecting damage to the anal sphincter complex

The aim of study was to investigate the differences between three-dimensional (3D) endosonography and two-dimensional (2D) endosonography in visualizing damage to the anal sphincter complex. 33 patients with a history of damage to the anal sphincters were examined with a 10 MHz rotating endoprobe. Cross-sectional images of the anal sphincters were stored on a 3D system during retraction of the endoprobe through the anal canal. Cross-sectional images (2D) were compared with reconstructed projections (3D) according to five parameters relating to damage of different parts of the sphincter muscles as well as scar-tissue formation in the rectovaginal septum. Depending on whether the investigator felt confident in diagnosis of scar tissue being present or not a numerical value of 1 or 0 was assigned. In this way a scale from 0 to 5 points was achieved, which ideally should be identical in 3D and 2D. Overall both observers felt diagnostic confidence in a median of five parameters (range 4-5) using 3D, compared with a median of four parameters (range 3-5) using 2D (p=0.001). When only assessing the four parameters relating to damage of different parts of the sphincter-muscles the observers felt diagnostic confidence in eight more cases using 3D than 2D. This difference did not reach statistical significance. The overall agreement between the two observers comparing all five parameters was 98.2% using 3D and 87.9% using 2D. 3D anal endosonography improves diagnostic confidence in detecting damage to the anal sphincter complex. The agreement between the two observers was acceptable using 2D but better when using 3D. The 3D method may improve the selection of patients for surgical repair of the anal sphincter complex.

Anal incontinence after obstetric sphincter tears: outcome of anatomic primary repairs

PURPOSE

Obstetric sphincter tears lead to anal incontinence in 40 to 60 percent of affected women. Primary repair is usually performed without identifying the internal anal sphincter. Since 1999 digestive surgeons have participated in the primary repair of such tears at our hospital. The intention was to perform separate repair of the internal and external anal sphincter in cases of combined tears to achieve a lower incontinence rate than is usually reported after conventional primary repair. The aim of the present study was to evaluate our results after anatomic primary repair.

METHOD

A follow-up study was undertaken after all primary repairs performed in 1999 and 2000. It included anal ultrasonography manometry and an assessment of incontinence (Wexner score).

RESULTS

A total of 74 women sustained obstetric sphincter tears during the study period, and 71 (96 percent) were assessed after a median of 27 months (range, 14-39 months). Nine women declined investigation with ultrasonography/manometry. Incontinence was present in 22 women (31 percent), of whom 17 had gas incontinence only. The symptoms were mild (Wexner score 1-2) in 11 women (50 percent). None of 17 women with normal ultrasonography results were incontinent versus 20 of 45 with pathologic ultrasonographic results (P = 0.001). The mean sphincter length, squeeze pressure, and resting pressure were significantly higher in women with Wexner scores of 0-2 vs. women with a score of more than 2. Sphincter length was inversely correlated with the degree of incontinence (P < 0.001).

CONCLUSIONS

The incontinence rate after anatomic primary repair is low compared with the last decade's reported results after conventional primary repair. A short anal sphincter after repair is associated with a poorer outcome.

Volume measurements of the anal sphincter complex in healthy controls and fecal-incontinent patients with a three-dimensional reconstruction of endoanal ultrasonography images

OBJECTIVES

The aim of this study was to determine sphincter volume, length, and external anal sphincter thickness in healthy controls and fecal incontinent patients by use of a three-dimensional reconstruction of endoanal ultrasonography images.

METHODS

Forty-four controls (15 males, 15 females, and 14 parous females) and 28 incontinent parous females (with and without a sphincter defect) were studied. Internal anal sphincter, external anal sphincter and puborectalis volume, sphincter length, and external anal sphincter thickness were measured. Intraobserver and interobserver variability were assessed. Anal pressure profile was also determined.

RESULTS

Internal anal sphincter and external anal sphincter volumes were larger in males than in females (P = 0.001 and P = 0.04), and external anal sphincter volume was smaller in parous females but this was not significant (P = 0.084). Anterior sphincter length was longer in males (P = 0.004) and shorter in parous females (P = 0.06). Males had a larger anterior external anal sphincter thickness (P = 0.018); parity made no difference. Sphincter volumes were not smaller in incontinent females. Incontinent females with a sphincter defect had a shorter anterior sphincter length than that of continent (P = 0.001) and incontinent females without a sphincter defect (P < 0.001). Anterior external anal sphincter thickness was smaller in incontinent females with a sphincter defect (P = 0.006), and posterior and right external anal sphincter thickness was smaller in incontinent females without a sphincter defect (P = 0.02 and P = 0.03). Intraobserver variability was seen for internal anal sphincter volume and sphincter length, but there was no interobserver variability. Correlation between anal pressures and endoanal ultrasonography measurements was poor.

CONCLUSIONS

Differences in anal sphincter volumes are seen for gender but not for parity. Fecal incontinence is not associated with loss of sphincter volume. However, anterior sphincter length and external anal sphincter thickness are smaller.

Hydrogen peroxide-enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging in evaluating perianal fistulas: agreement and patient preference

OBJECTIVES

To determine agreement between hydrogen peroxide-enhanced three-dimensional endoanal ultrasonography (3D HPUS) and endoanal magnetic resonance imaging (MRI) in preoperative assessment of perianal fistulas, and to assess patient preference with regard to these techniques.

METHODS

Forty patients (31 males, aged 21-70 years) with symptoms of a perianal fistula and a visible external opening underwent preoperative 3D HPUS and endoanal MRI. The results were assessed separately by experienced observers. Fistulas were described according to the following characteristics: classification of the primary fistula tract according to Parks, location of the internal opening, presence of secondary tracts and fluid collections. Patients were asked to score the amount of discomfort experienced during both procedures and express their preference for either method.

RESULTS

The median time interval between 3D HPUS and endoanal MRI was 14 days (range, 0-91 days). The methods agreed in 88% (35/40, kappa = 0.45) for the primary fistula tract, in 90% (36/40, kappa = 0.83) for the location of the internal opening, in 78% (31/40, kappa = 0.62) for secondary tracts, and in 88% (35/40, kappa = 0.63) for fluid collections. Both methods were associated with similar discomfort, and there was no patient preference for one procedure over the other.

CONCLUSIONS

3D HPUS and endoanal MRI are equally adequate for the evaluation of perianal fistulas. Both methods are associated with similar discomfort and patients have no preference for either procedure.