Preoperative assessment of simple and complex anorectal fistulas: Tridimensional endoanal ultrasound? Magnetic resonance? Both?

Impact of Preoperative Three-Dimensional Endoanal Ultrasound on the Surgical Outcome of Primary Fistula in Ano. A Multi-Center Observational Study of 253 Patients

PURPOSE

To evaluate the impact of preoperative three-dimensional endoanal ultrasound (3D-EAUS) on the clinical outcome of anal fistula surgery.

METHODS

The research consisted of multi-center retrospective case-control study including 253 consecutive adult patients undergoing surgery for confirmed or suspected primary fistula in ano who had undergone preoperative 3D-EAUS evaluation between January 2011 and January 2021. Main outcome measures were the concordance (K value) between ultrasound results and surgery in the identification of fistulas internal openings, primary tracts and secondary extensions and the 6 and 12 months success rate in patients with concordant and discordant findings.

RESULTS

A good agreement in the identification of the main fistulas characteristics between ultrasound results and operative findings was found. A significant difference (P < .0001; Fisher's exact test) in the success rate was found between patients with concordant and discordant ultrasound results and operative findings in identification or location of internal opening. Particularly, all the 11 (4.8%) patients with discordant results experimented a failure of the surgical procedure at 6 months follow-up. At re-operation, the shift from discordant to concordant results was associated with an 81.8% 12 months success-rate.

CONCLUSION

The three-dimensional endoanal ultrasound preoperative evaluation may have a relevant impact on the outcome of a defined group of patients undergoing surgery for anal fistula, since the careful evaluation of ultrasound results could simplify the internal orifice intra-operative detection and improve the success rate.

Preoperative Assessment of Perianal Fistulas with Combined Magnetic Resonance and Tridimensional Endoanal Ultrasound: A Prospective Study

BACKGROUND

we designed a prospective study of diagnostic accuracy that compared pelvic MRI and 3D-EAUS with pelvic MRI alone in the preoperative evaluation and postoperative outcomes of patients with perianal fistulas.

METHODS

the sample size was 72 patients and this was divided into two imaging groups. MRI alone was performed on the first group. Both MRI and 3D-EAUS were performed in parallel on the second group. Surgical exploration took place after two weeks and was the standard reference. Park's classification, the presence of a concomitant abscess or a secondary tract, and the location of the internal opening were recorded. All patients were re-evaluated for complete fistula healing and fecal incontinence six months postoperatively. All of the collected data were subjected to statistical analysis.

RESULTS

the MRI group included 36 patients with 42 fistulas. The MRI + 3D-EAUS group included 36 patients with 46 fistulas. The adjusted sensitivity and negative predictive value were 1.00 for most fistula types in the group that underwent combined imaging. The adjusted specificity improved for intersphincteric fistulas in the same group. The adjusted balanced accuracy improved for all fistula types except rectovaginal. The combination of imaging methods showed improved diagnostic accuracy only in the detection of a secondary tract. The healing rate at six months was 100%. Fecal incontinence at six months did not present a statistically significant difference between the two groups (Fisher's exact test p-value > 0.9). Patients with complex perianal fistulas had a statistically significant higher probability of undergoing a second surgery (x2 test p-value = 0.019).

CONCLUSIONS

the combination of pelvic MRI and 3D-EAUS showed improved metrics of diagnostic accuracy and should be used in the preoperative evaluation of all patients with perianal fistulas, especially those with complex types.

Sacral nerve modulation for patients with fecal incontinence: long-term outcome and effects on sexual function

Sacral nerve modulation has become an established treatment for fecal and urinary incontinence, and sexual disorders. The objective of this study was to evaluate the long-term outcome of sacral neuromodulation in patients with fecal or combined fecal and urinary incontinence (double incontinence), assessing its safety, efficacy, and impact on quality of life and sexual function. This was a multicentric, retrospective, cohort study including patients with fecal or double incontinence who received sacral neuromodulation at seven European centers between 2007 and 2017 and completed a 5-year follow-up. The main outcome measures included improvements of incontinence symptoms and quality of life compared with baseline, evaluated using validated tools and questionnaires at 1-, 6-, 12-, 36- and 60-month follow-up. 108 (102 women, mean age 62.4 ± 13.4 years) patients were recruited, of whom 88 (81.4%) underwent definitive implantation of the pacemaker. Patients' baseline median Cleveland Clinic Incontinence Score was 15 (10-18); it decreased to 2 (1-4) and 1 (1-2) at the 12- and 36-month follow-up (p < 0.0001), remaining stable at the 5-year follow-up. Fecal incontinence quality of life score improved significantly. All patients with sexual dysfunction (n = 48) at baseline reported symptom resolution at the 5-year follow-up. The study was limited by the retrospective design and the relatively small patient sample. Sacral nerve modulation is an effective treatment for fecal and double incontinence, achieving satisfactory long-term success rates, with resolution of concomitant sexual dysfunction.

Comparison of contrast-enhanced fat-suppressed T1-3D-VIBE and T1-TSE MRI in evaluating anal fistula

OBJECTIVE

To evaluate the accuracy of contrast-enhanced (CE) fat-suppressed three-dimensional (3D) T1-weighted imaging with volumetric interpolated breath-hold examination (FS-T1-3D-VIBE) and fat-suppressed T1-weighted turbo spin echo (FS-T1-TSE) sequence in characteristics of anal fistula.

METHODS

One hundred and two patients underwent perianal CE-MRI examination on a 3T scanner including FS-T1-3D-VIBE and FS-T1-TSE sequences before surgery. The performance of each sequence was evaluated in terms of fistula classification, clarity of internal opening, number and position of internal openings including the distance between internal opening and anal verge, presence of secondary tracts and blind-ending sinus tracts. MRI findings were compared with surgical findings. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of fistula, gluteus maximus, and subcutaneous fat were compared between CE FS-T1-TSE and CE FS-T1-3D-VIBE.

RESULTS

Compared with CE FS-T1-TSE, CE FS-T1-3D-VIBE displayed more accurate in secondary tract, lithotomy position of the internal opening and the distance between internal opening and anal verge (P < 0.05). CE FS-T1-3D-VIBE was found superior to CE FS-T1-TSE in the clarity of the internal openings and in the diagnostic accuracy of blind-ending sinus tracts and complex fistulas in Standard Practice Task Force classification (P < 0.05). CE FS-T1-3D-VIBE achieved higher SNRs and CNRs in fistula and gluteus maximus than CE FS-T1-TSE (P ≤ 0.001).

CONCLUSION

CE-MRI of FS-T1-3D-VIBE might be a more valuable noninvasive technique than FS-T1-TSE to evaluate the anal fistula on evaluating the lithotomy position of internal opening, distance between internal opening and anal verge, clarity of internal opening, secondary tract, blind-ending sinus tract and classification of the complex fistula. The trial registration number for this prospective trial was Chi-TR1800020206 and the trial registration date was December 20, 2018.

Benign Anorectal Disorder Management in Low-Resource Settings

There are many benign anorectal disorders, which can make patients seek care. In low-resource settings, the incidence of those pathologies is not different from the industrialized and western world. However, an interesting difference colorectal surgeons and gastroenterologists can face is the fact that many patients do not seek help or are not aware and have little opportunities to be helped. Latin America population is estimated to be around 8% of the world population, with Brazil having the largest percentage. Infectious diseases, which were previously under control or were steadily declining, have emerged. For example, we have seen resurgence of dengue, malaria, and syphilis in pregnancy, as well as other sexually transmitted diseases that can affect the anorectal region. In this article, we will address the most common benign anorectal disorders.

Guidelines to diagnose and treat peri-levator high-5 anal fistulas: Supralevator, suprasphincteric, extrasphincteric, high outersphincteric, and high intrarectal fistulas

Supralevator, suprasphincteric, extrasphincteric, and high intrarectal fistulas (high fistulas in muscle layers of the rectal wall) are well-known high anal fistulas which are considered the most complex and extremely challenging fistulas to manage. Magnetic resonance imaging has brought more clarity to the pathophysiology of these fistulas. Along with these fistulas, a new type of complex fistula in high outersphincteric space, a fistula at the roof of ischiorectal fossa inside the levator ani muscle (RIFIL), has been described. The diagnosis, management, and prognosis of RIFIL fistulas is reported to be even worse than supralevator and suprasphincteric fistulas. There is a lot of confusion regarding the anatomy, diagnosis, and management of these five types of fistulas. The main reason for this is the paucity of literature about these fistulas. The common feature of all these fistulas is their complete involvement of the external anal sphincter. Therefore, fistulotomy, the simplest and most commonly performed procedure, is practically ruled out in these fistulas and a sphincter-saving procedure needs to be performed. Recent advances have provided new insights into the anatomy, radiological modalities, diagnosis, and management of these five types of high fistulas. These have been discussed and guidelines formulated for the diagnosis and treatment of these fistulas for the first time in this paper.

Perianal fistulas: A review with emphasis on preoperative imaging

PURPOSE

We aim to present a comprehensive literature review which focuses on the preoperative imaging of perianal fistulas.

MATERIAL/METHODS

Pelvic magnetic resonance imaging (MRI) and endoanal ultrasound (EAUS) are the two first-line imaging modalities for the preoperative evaluation of patients with perianal fistulas. We conducted a search in PubMed, Scopus and Google Scholar concerning articles comparing pelvic MRI with EAUS, which were published from 1994 until 2019.

RESULTS

In most articles, pelvic MRI is superior to EAUS for the evaluation of perianal fistulas (especially for supralevator and extrasphincteric ones). Preoperative pelvic MRI is associated with statistically significant better results and prognosis after surgical treatment of the disease. Preoperative EAUS poses high sensitivity and specificity in identifying intersphincteric and transsphincteric perianal fistulas, as well as the internal opening of a fistula-in-ano. There is only one meta-analysis which compares the diagnostic accuracy of the two mentioned imaging modalities in preoperative fistula detection. Sensitivity of both - pelvic MRI and EAUS, is acceptably high (0.87). Specificity of pelvic MRI is 0.69 in comparison to EAUS (0.43), but both values are considered low.

CONCLUSIONS

Future well-designed prospective studies are needed to investigate the diagnostic accuracy of pelvic MRI and EAUS in the preoperative assessment of patients with perianal fistulas. Moreover, the combination of pelvic MRI and EAUS should also be studied, since several published articles suggest that it could lead to improved diagnostic accuracy. A novel treatment algorithm for perianal fistulas could arise from this study.

Treating highly complex anal fistula with a new method of combined intraoperative endoanal ultrasonography (IOEAUS) and transanal opening of intersphincteric space (TROPIS)

Introduction

Treatment of highly complex anal fistula is still a profound test for a specialist colorectal surgeon. The reasons are directly related to recurrence and incontinence.

Aim

To evaluate the clinical results of a combined method of intraoperative endoanal ultrasonography (IOEAUS) and transanal opening of the intersphincteric space (TROPIS).

Material and methods

This study retrospectively included 48 patients with complex anal fistula, all of whom underwent new surgical methods. This operation mainly consists of two steps. Firstly, the type of anal fistula was determined by endoanal ultrasonography (EAUS) or magnetic resonance imaging (MRI) before the operation. Then the TROPIS procedure was performed with the help of EAUS, and the decision on whether a drainage seton should be placed depended on the condition of the tract. If there were secondary tracts, they were found and the same was done.

Results

The median follow-up was 12 months. Two (4.1%) patients experienced recurrence. Four (8.3%) patients did not have primary healing. All 6 patients underwent the same procedure again, and three recovered completely. So total successful fistula healing was observed in 45 (93.7%). There were no major complications and no significant deterioration in anal function and incontinence postoperatively.

Conclusions

Combined IOEAUS and TROPIS is an effective procedure in the treatment of highly complex anal fistula, and it may offer a new means for other operations.

Dynamic contrast-enhanced (DCE) imaging: state of the art and applications in whole-body imaging

Dynamic contrast-enhanced (DCE) imaging is a non-invasive technique used for the evaluation of tissue vascularity features through imaging series acquisition after contrast medium administration. Over the years, the study technique and protocols have evolved, seeing a growing application of this method across different imaging modalities for the study of almost all body districts. The main and most consolidated current applications concern MRI imaging for the study of tumors, but an increasing number of studies are evaluating the use of this technique also for inflammatory pathologies and functional studies. Furthermore, the recent advent of artificial intelligence techniques is opening up a vast scenario for the analysis of quantitative information deriving from DCE. The purpose of this article is to provide a comprehensive update on the techniques, protocols, and clinical applications - both established and emerging - of DCE in whole-body imaging.

ACR Appropriateness Criteria® Anorectal Disease

This review summarizes the relevant literature for the selection of the initial imaging in 4 clinical scenarios in patients with suspected inflammatory disease or postoperative complication of the anorectum. These clinical scenarios include suspected perianal fistula or abscess; rectovesicular or rectovaginal fistula; proctitis or pouchitis; and suspected complication following proctectomy, coloproctectomy, or colectomy with a pouch or other anastomosis. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios of anorectal disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Perianal Imaging in Crohn Disease: Current Status With a Focus on MRI, From the AJR Special Series on Imaging of Inflammation

Fistulizing perianal disease is a frequent, chronic, and often debilitating manifestation of Crohn disease (CD) in adults and children, which in the past was relatively refractory to treatment. The advent of biologic agents such as anti-tumor necrosis factor-α and cellular therapies, used in conjunction with a range of surgical interventions, has greatly improved disease outcomes, although complete remission can still be elusive. This review considers current perianal imaging options, specifically pelvic MRI and endoanal and transperineal ultrasound, and their roles in diagnosis, management, and assessment of treatment response. Pelvic MRI is the first line technique for imaging of perianal CD given the complexity of fistulas encountered in CD. MRI technical acquisition parameters for adults and children and an approach to MRI interpretation and reporting are provided. Anatomic classification systems for fistulising perianal disease are presented. We also explore the history, current landscape, and future developments of MRI features of perianal disease as imaging biomarkers to quantify activity and severity, and consider CD MRI-based inflammatory activity scores. We discuss the reliability and validation of a number of indices (including PEMPAC, MAGNIFI-CD, mVAI, and Van Assche Index), their potential to quantify treatment response, and possible prognostic capabilities.

Deep Learning-Based CT Image Characteristics and Postoperative Anal Function Restoration for Patients with Complex Anal Fistula

Objective

This study aimed to optimize the CT images of anal fistula patients using a convolutional neural network (CNN) algorithm to investigate the anal function recovery.

Methods

57 patients with complex anal fistulas admitted to our hospital from January 2020 to February 2021 were selected as research subjects. Of them, CT images of 34 cases were processed using the deep learning neural network, defined as the experimental group, and the remaining unprocessed 23 cases were in the control group. Whether to process CT images depended on the patient's own wish. The imaging results were compared with the results observed during the surgery.

Results

It was found that, in the experimental group, the images were clearer, with DSC = 0.89, precision = 0.98, and recall = 0.87, indicating that the processing effects were good; that the CT imaging results in the experimental group were more consistent with those observed during the surgery, and the difference was notable (P < 0.05). Furthermore, the experimental group had lower RP (mmHg), AMCP (mmHg) scores, and postoperative recurrence rate, with notable differences noted (P < 0.05).

Conclusion

CT images processed by deep learning are clearer, leading to higher accuracy of preoperative diagnosis, which is suggested in clinics.

Large Bowel Ischemia/Infarction: How to Recognize It and Make Differential Diagnosis? A Review

Ischemic colitis represents the most frequent form of intestinal ischemia occurring when there is an acute impairment or chronic reduction in the colonic blood supply, resulting in mucosal ulceration, inflammation, hemorrhage and ischemic necrosis of variable severity. The clinical presentation is variable and nonspecific, so it is often misdiagnosed. The most common etiology is hypoperfusion, almost always associated with generalized atherosclerotic disease. The severity ranges from localized and transient ischemia to transmural necrosis of the bowel wall, becoming a surgical emergency, with significant associated morbidity and mortality. The diagnosis is based on clinical, laboratory suspicion and radiological, endoscopic and histopathological findings. Among the radiological tests, enhanced-CT is the diagnostic investigation of choice. It allows us to make the diagnosis in an appropriate clinical setting, and to define the entity of the ischemia. MR may be adopted in the follow-up in patients with iodine allergy or renal dysfunctions, or younger patients who should avoid radiological exposure. In the majority of cases, supportive therapy is the only required treatment. In this article we review the pathophysiology and the imaging findings of ischemic colitis.

Using preoperative three-dimensional endoanal ultrasound to determine operative procedure in patients with perianal fistulas

AIM

Accurate preoperative identification of perianal fistula tracts and internal openings can facilitate the choice of surgical procedure and may lead to improved healing rates. Our aim was to explore the effectiveness of three-dimensional endoanal ultrasound (3D-EAUS) in determining the type of perianal fistula and planning operative management.

METHOD

This was a cohort longitudinal study. Patients with perianal fistulas from January 2017 to January 2018 who underwent 3D-EAUS and subsequent surgery were included. Intra-operative findings were considered as standard for comparison with clinical examination and 3D-EAUS findings. The primary outcome measure was to evaluate the concordance between 3D-EAUS and intra-operative findings and the secondary outcome measure was healing rates.

RESULTS

Sixty-eight patients with a mean age of 43.1 ± 14.1 years were included. Twenty-eight patients had inter-sphincteric (41.2%) and 40 (14 high and 26 low) trans-sphincteric fistulas (58.8%). 3D-EAUS, clinical examination and intra-operative exploration could predict the location of internal openings in 62/68 (91.2%), 48/68 (70.5%) and 56/68 (82.4%) patients, respectively. Hydrogen peroxide (H₂O₂)-enhanced 3D-EAUS accurately predicted the location of internal openings when compared with 3D-EAUS without H₂O₂ (concordance K = 0.963, P = 0.05). High concordance rates were seen between intra-operative and 3D-EAUS findings on the type of perianal fistula. No significant difference was seen between the suggested surgical treatment based on 3D-EAUS and the eventual surgical treatment (P > 0.05). Study limitations were the small sample size and lack of randomization.

CONCLUSION

3D-EAUS may be considered as a first-line investigation for patients with perianal fistulas because of high concordance with intra-operative assessment and facilitation of surgical planning.

Recurrent anal fistulas: When, why, and how to manage?

Anal fistula is a commonly encountered anal condition in the surgical practice. Despite being a benign condition, anal fistula remains to represent a surgical challenge, particularly the complex type of fistulas. One of the common complications of anal fistula surgery is the persistence or recurrence of the pathology, both defined as failure of surgery. Recurrent anal fistulas after previous surgery represent an even more challenging problem since they are usually associated with a higher risk of re-recurrence and continence disturbance. The present review aimed to shed light on various aspects of recurrent anal fistulas, including the different definitions of failure after surgery, risk factors of recurrence, problems associated with management of recurrent fistulas, and assessment and treatment of recurrent anal fistulas.

Three-dimensional endoanal ultrasound should be considered as first-line diagnostic tool in the preoperative work-up for perianal fistulas : The authors reply to the letter: Mathew RP, Patel V, Low G. Caution in using 3D-EAUS as the first-line diagnostic tool in the preoperative work up for perianal fistulas. Radiol Med 2020;125:155-156

In the preoperative work-up of patients with anorectal fistulas, 3D-EAUS may represent the first-line diagnostic tool, showing high diagnostic accuracy in the evaluation of internal openings, primary tracks and secondary extension. In the cases of fistulas classified as complex by 3D-EAUS, MRI may be indicated as adjunctive diagnostic imaging examination, to more accurately detect the fistulas' secondary extensions, and so, to more carefully describe the fistulas' complete anatomy.

Caution in using 3D-EAUS as the first-line diagnostic tool in the preoperative work up for perianal fistulas

MRI is considered the de facto imaging modality for evaluating perianal fistulas, primarily due to its excellent soft tissue contrast, operator independence, multiplanar capabilities and excellent field of view. Tridimensional endoanal ultrasound (3D-EAUS) is inferior to MRI in identifying and/or evaluating ischiorectal/supralevator tracks/extensions and therefore could end up providing incomplete and even inaccurate information (e.g. misclassification of tracks) to the surgeon, with a missed track potentially leading to recurrence of the disease.