The accuracy of a postprocessing technique--volume render mode--in three-dimensional endoanal ultrasonography of anal abscesses and fistulas

Use of 3D Anorectal Ultrasonography in the Preoperative Assessment of Complex Anal Fistulas and Patterns of Healing, Failure, and Recurrence After Ligation of the Intersphincteric Fistula Tract (LIFT)

OBJECTIVES

To use three-dimensional anorectal ultrasonography (3D-US) to evaluate the outcome of ligation of the intersphincteric fistula tract (LIFT) in patients with crypto-glandular transsphincteric fistula and describing the patterns of healing, failure, and recurrence rate.

METHODS

After classifying the fistula and determining the length of the sphincter muscle to be transected, the patients were submitted to LIFT. The accuracy of pre- and postoperative 3D-US with 360° endoprobe (16 MHz) with automatic scanning and clinical findings was evaluated against surgical findings. Three outcomes were considered: healing, failure (persistent anal fistula through the original external opening or intersphincteric), and recurrence (reappearance of the anal fistula).

RESULTS

Sixty-three patients of both sexes were evaluated. The 3D-US assessment revealed primary healing in 50 (79.3%) patients, although in 6 (9.5%) cases healing was delayed and the cavity was without communication with the anal canal. The procedure failed in 9 (15.9%) and fistula recurred in 4 (6.3%), all of whom underwent a second surgery based on a new 3D-US, resulting in a 92.3% (12/13) healing rate on 3D-US.

CONCLUSIONS

A 3D-US was found to be useful in the preoperative assessment of fistulas by quantifying the percentage of muscle to be transected, and in the postoperative assessment by identifying healing, types of failure, and recurrence. The 3D-US was accurate and consistent with surgical findings.

A mini-invasive procedure for the treatment of supralevator abscess of cryptoglandular origin by extrasphincteric extension: preliminary results at 1-year follow-up

AIM

The aim of this retrospective study is to evaluate the preliminary results of a mini-invasive procedure for the treatment of supralevator abscesses (SLA) of cryptoglandular origin by extrasphincteric extension.

METHOD

In this clinical study, an innovative two-stage procedure was tested for the surgical treatment of SLA. As first step and as a preparation for surgery, the interventional radiologist positioned a CT-guided percutaneous perianal guidewire inside the abscess cavity under local anesthesia. As second step, the surgeon performed an abscess incision and drainage around the guidewire, with a complete debridement of all the necrotic tissue. If a complex anal fistula was identified, a loose seton was placed in situ.

RESULTS

Nine patients, comprising 5 men (55%) and 4 women (45%), underwent the above-mentioned two-stage procedure to treat SLA of cryptoglandular origin. Median age was 32 years (range, 25-42 years). A silicone draining seton was placed during the surgical procedure in 5 patients (55%), since a coexisting fistula was also revealed by surgery. A repeat surgery, along with a new drainage procedure, was required in one patient out of nine (11.1%) for a complete wound healing. The complete wound healing was achieved after a median of 30 days (range, 26-38). At the 1-year follow-up, the healing rate was 89%.

CONCLUSIONS

The treatment of SLA of cryptoglandular origin by using this innovative two-stage procedure may be a safe and convenient surgical option to effectively decrease the risk of recurrence and anal sphincteric injuries.

Utility of Endoanal Ultrasonography in Assessment of Primary and Recurrent Anal Fistulas and for Detection of Associated Anal Sphincter Defects

BACKGROUND

Tridimensional endoanal ultrasonography (3D-EAUS) has been used for the assessment of various anorectal lesions. Previous studies have reported good accuracy of 3D-EAUS in preoperative assessment of fistula-in-ano (FIA). This study aimed to assess the diagnostic utility of 3D-EAUS in preoperative evaluation of primary and recurrent FIA and its role in detection of associated anal sphincter (AS) defects.

PATIENTS AND METHODS

Prospectively collected data of patients with FIA who were investigated with 3D-EAUS were reviewed. The findings of EAUS were compared with the intraoperative findings, the reference standard, to find the degree of agreement regarding the position of the internal opening (IO) and primary tract (PT), and presence of secondary tracts using kappa (k) coefficient test. A subgroup analysis was performed to compare the accuracy and sensitivity of EAUS for primary and recurrent FIA.

RESULTS

Of the patients, 131 were included to the study. EAUS had an overall accuracy of 87, 88.5, and 89.5% in detection of IO, PT, and AS defects, respectively. There was very good concordance between the findings of EAUS and intraoperative findings for the investigated parameters (kappa = 0.748, 0.83, 0.935), respectively. Accuracy and sensitivity of EAUS in recurrent FIA were insignificantly lower than primary cases. EAUS detected occult AS defects in 5.3% of the patients studied.

CONCLUSION

The diagnostic utility of 3D-EAUS was comparable in primary and recurrent FIA. 3D-EAUS was able to detect symptomatic and occult AS defects with higher accuracy than clinical examination.

Three-dimensional endoanal ultrasound is accurate and reproducible in determining type and height of anal fistulas

AIM

Surgical treatment of high anal fistulas is associated with the potential risk of faecal incontinence and recurrence. The primary aim of this study was to determine the accuracy of three-dimensional endoanal ultrasound (3D-EAUS) in the assessment of height and type of anal fistulas, compared to the intra-operative findings (gold standard). The secondary aim was to evaluate the inter-observer reproducibility of 3D-EAUS.

METHOD

The study design was a prospective analysis of retrospective data. 299 patients (202 men), mean age 45.3 years, who underwent surgery for anal fistulas, were included. All patients were preoperatively assessed by 3D-EAUS. Two readers independently reviewed the volumes to determine the type and height of fistulas. Sensitivity, specificity, positive and negative predictive values, proportion of agreements and Cohen's kappa coefficient (κ) were calculated for both examiners. Ultrasound findings were compared with intra-operative data (reference standard), evaluated blindly by the surgeons.

RESULTS

At surgery, 201 (67%) were transsphincteric, 49 (16%) suprasphincteric, 47 (16%) intersphincteric and two (1%) extrasphincteric fistulas. Intra-operatively, 177 (59%) were low and 122 (41%) high fistulas. The overall accuracy of 3D-EAUS was 91% for fistula type (271/299 fistulas: 97% transsphincteric, 100% intersphincteric, 57% suprasphincteric, 0% extrasphincteric) and 92% for fistula height (275/299 fistulas: 80% high and 100% low). Both readers reported very good agreement with surgery in the assessment of fistula type (proportion of agreement 0.88, κ = 0.89) and height (proportion of agreement 0.90, κ = 0.91).

CONCLUSIONS

3D-EAUS is an accurate and reproducible modality for the assessment of type and height of anal fistulas.

Role of ultrasound in colorectal diseases

Ultrasound is an undervalued non-invasive examination in the diagnosis of colonic diseases. It has been replaced by the considerably more expensive magnetic resonance imaging and computed tomography, despite the fact that, as first examination, it can usefully supplement the diagnostic process. Transabdominal ultrasound can provide quick information about bowel status and help in the choice of adequate further examinations and treatment. Ultrasonography, as a screening imaging modality in asymptomatic patients can identify several colonic diseases such as diverticulosis, inflammatory bowel disease or cancer. In addition, it is widely available, cheap, non-invasive technique without the use of ionizing radiation, therefore it is safe to use in childhood or during pregnancy, and can be repeated at any time. New ultrasound techniques such as elastography, contrast enhanced and Doppler ultrasound, mini-probes rectal and transperineal ultrasonography have broadened the indication. It gives an overview of the methodology of various ultrasound examinations, presents the morphology of normal bowel wall and the typical changes in different colonic diseases. We will pay particular attention to rectal and transperineal ultrasound because of their outstanding significance in the diagnosis of rectal and perineal disorders. This article seeks to overview the diagnostic impact and correct indications of bowel ultrasound.

Magnetic resonance imaging and endorectal ultrasound for diagnosis of rectal lesions

Endorectal ultrasonography (ERUS) and magnetic resonance imaging (MRI) allow exploring the morphology of the rectum in detail. Use of such data, especially assessment of the rectal wall, is an important tool for ascertaining the perianal fistula localization as well as stage of the cancer and planning it appropriate treatment, as stage T3 tumors are usually treated with neoadjuvant therapy, whereas T2 tumors are initially managed surgically. The only advantage of ERUS over MRI is the possibility of assessing T1 tumors that could be treated by transanal endoscopic microsurgery. However, MRI is better for visualizing most radiological prognostic features in rectal or anal cancer such as a circumferential resection margin less than 1 mm, T stage at T1-T2 or T3 tumors with extramural extension less than 5 mm, absence of extramural vascular invasion, N stage at N0/N1, and tumors located in the middle or upper third of the rectum. It can also evaluate the intersphincteric space or levator ani muscle involvement. Increased signal on diffusion weighted imaging (DWI) and low apparent diffusion coefficient (ADC) values as well as an irregular contour and heterogeneous internal signal intensity seem to predict the involvement of pelvic lymphatic nodes better than their size alone. Computed tomography as well as other examination techniques, including digital rectal examination, contrast edema, recto- and colonoscopy, are less useful in staging of rectal cancer but still are very important screening tools.

Ultrasonographic evaluation of anal endometriosis: report of four cases

BACKGROUND

The presence of endometriosis in the anal canal and perianal tissues is rare and difficult to suspect at clinical examination. We report our experience with preoperative ultrasound evaluation of four cases of anal endometriosis.

METHODS

Four patients were evaluated by transperineal and high-resolution three-dimensional endoanal ultrasonography.

RESULTS

In 3 of 4 women, the lesions involved old episiotomy scars. Anal endometriosis appeared as hypoechoic cystic lesions with areas of microcalcification, not well delimited and highly vascularized. The lesions either involved the anal sphincter (n = 2, one within the rectovaginal septum) or were localized superficially in the ischiorectal space (n = 2). Surgery and pathologic exam confirmed the ultrasonographic findings.

CONCLUSIONS

Ultrasonographic findings of anal endometriosis are characteristics and may allow accurate preoperative staging of the disease.

Methods for preoperative assessment of anal fistula

Anal fistula is one of the most common perianal diseases, and methods for its preoperative assessment are diverse. Traditional methods include physical examination, probing, Goodsall's law, methylene blue test, and so on. Although traditional methods play a role, their accuracy for complex anal fistulas is low. Therefore, their application must be combined with other methods. Fistulography fails to depict the relationship of the fistula to the sphincter complex, and computed tomography lacks specificity to distinguish between fistula and surrounding muscle tissue. Both methods are rarely used now. Magnetic resonance imaging and three-dimensional anorectal endosonography have become routine preoperative examinations and play an important role for guiding precise surgery. However, they also have their own shortcomings. In this paper, we will summarize a variety of methods for preoperative assessment of anal fistula.