Normal anal sphincter anatomy and age- and sex-related variations at high-spatial-resolution endoanal MR imaging

Exploring pelvic floor muscle function in men with and without pelvic floor symptoms: A population-based study

BACKGROUND

Pelvic floor symptoms (PFS), such as lower urinary tract symptoms, defecation disorders, sexual problems, and genital-pelvic pain, are prevalent in men. Thorough physical assessments of the external anal sphincter (EAS) and the puborectal muscle (PRM) are the keys to unraveling the role of muscle dysfunction.

OBJECTIVES

To explore associations within and between the EAS and PRM and between muscle (dys-) function and the number of male PFS.

METHODS

This cross-sectional study purposively enrolled men aged ≥21 years with 0-4 symptoms from a larger study. After extensive external and internal digital pelvic floor assessment, we explored (1) agreement between muscle function of the EAS versus PRM (using cross tabulation), (2) associations within and between the EAS and PRM (using heatmaps), and (3) associations between muscle function and number of PFS (using a visual presentation [heatmaps] and χ²  tests).

RESULTS

Overall, 42 out of 199 men (21%) had completely normal muscle function. Sixty-six (33.2%) had no symptoms, of which 53 (80%) had some degree of muscle dysfunction. No clear dose-response relationship existed between muscle (dys-) function and the number of symptoms. The PRM showed both more dysfunction and severer dysfunction than the EAS.

CONCLUSIONS

No clear association exists between muscle dysfunction and the number of symptoms, and the absence of PFS does not indicate normal muscle function for all men. Dysfunction levels are highest for the PRM. Further pelvic floor muscle research is warranted in men with PFS.

An anatomical study on intersphincteric space related to intersphincteric resection for ultra-low rectal cancer

BACKGROUND

Intersphincteric resection (ISR) has been proposed to offer sphincter-sparing solution for patients with ultra-low rectal cancer. However, complete and accurate concepts about the intersphincteric space (ISS) related anatomy are not demonstrated clearly. This study aimed to provide a comprehensive description about the anatomic structure of ISS related to ISR.

METHODS

This was a descriptive morphological study. 28 pelvic specimens were obtained from body donors. Macroscopic and microscopic observation of ISS was performed via gross anatomy, plastinated sections and histologic staining. The anatomical parameters of the anal canal were measured. Images of laparoscopic ISS dissection procedures were real-timely captured during ISR.

RESULTS

The hiatal ligament, microvessels on supra fascia of LAM and rectal longitudinal muscle at the level of anorectal ring, especially at 1, 5, 7, and 11o'clock, could be the preferred entrance of ISS. The conjoint longitudinal muscle (CLM), the major component of ISS, was the continuum of the rectal longitudinal muscle and got reinforcement from the elastic fibers from LAM and EAS. Microvessels and neuro tissues were also found in ISS. The ISS was split into two spaces by the CLM in the middle and might subjectively be divided into three segments according to its different compositions. The length and width of ISS varied from different segments and directions.

CONCLUSIONS

We provided a systemic description of boundaries, contents and topographic structure of ISS, which may help proper determination of surgical approaches and dissection planes during ISR.

Anal fistula at roof of ischiorectal fossa inside levator-ani muscle (RIFIL): a new highly complex anal fistula diagnosed on MRI

BACKGROUND

As experience with anal fistula imaging (MRI) has increased, new pathways of fistula extension have been identified. A recently described pathway is the  'outer-sphincteric space' present between the external anal sphincter and its covering outer fascia. A new type of complex fistula is being described which is present in the outer-sphincteric space and continues superiorly along the lateral border of the external anal sphincter to the infero-lateral surface of the puborectalis and levator-ani. In effect, these outer-sphincteric fistulas are at the roof of the ischiorectal fossa inside the levator muscle (RIFIL). These fistulas are not transsphincteric fistulas as they remain inside the levator muscle and do not enter the ischiorectal fossa.

METHODS

The MRI scans of consecutive anal fistula patients operated over the last two years were analyzed retrospectively.

RESULTS

Of 419 operated fistula patients analyzed, 42(10%) had RIFIL and 377 non-RIFIL fistulas. Compared to non-RIFIL fistulas, there were significantly more recurrent, multiple tracts, horseshoe, supralevator, and suprasphincteric fistulas in the RIFIL group. RIFIL fistulas were significantly more complex than non-RIFIL fistulas(85.7% vs 38.5%, p < 0.00001) and the surgery failure rate was also significantly higher in the RIFIL group (30.6%) than in the non-RIFIL fistula (7.2%) group(p = 0.0001).

CONCLUSION

RIFIL are highly complex fistulas. Proper diagnosis by MRI, surgical access, and subsequent management of these fistulas is quite challenging and they are associated with poor prognosis. Missing their diagnosis would lead to higher recurrence rate. These have not been described previously and were perhaps confused with high transsphincteric infralevator fistulas in ischiorectal fossa.

Location of obstetric anal sphincter injury scars on translabial tomographic ultrasound

OBJECTIVE

Obstetric anal sphincter injury (OASI) is a common preventable cause of anal incontinence. Both diagnosis and primary repair of OASI are often suboptimal, partly owing to the absence of effective clinical audit. The aim of this study was to evaluate the location of scars or defects of the external anal sphincter (EAS), diagnosed by translabial ultrasound (TLUS), following primary OASI repair.

METHODS

This was a retrospective analysis of 309 women who were seen at a tertiary obstetric unit after primary repair of OASI between June 2012 and May 2019. All women underwent a standardized interview, including St Mark's incontinence score, followed by clinical examination and TLUS assessment within 2-9 months after OASI repair. Postprocessing of TLUS volume datasets was performed by an investigator who was blinded to all other information. Tomographic ultrasound imaging was used to evaluate the presence of a scar or defect in the proximal and distal parts of the EAS. Women were classified into four groups according to the imaging findings: (1) no visible defect or distortion (likely false positive); (2) only proximal OASI; (3) only distal OASI; and (4) both proximal and distal OASI.

RESULTS

Of the 309 women seen during the study period, 34 were excluded because they were referred for reasons other than recent (< 1 year) OASI, 16 owing to missing data and four owing to poor image quality, leaving 255 patients for analysis. Women were seen on average 0.25 ± 0.1 years after the index birth, and their mean age at delivery was 29.1 ± 4.6 years. Anal incontinence was reported by 97 (38.0%) women. A scar or defect was seen only in the proximal part of the EAS in 64 (25.1%) women and only in the distal part in 19 (7.5%) (P < 0.001). In 165 (64.7%) women, the damage affected both the proximal and distal EAS.

CONCLUSIONS

EAS scars after primary OASI repair commonly affect the entire length of the EAS; however, partial tears seem to be more likely to occur proximally. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Safety and effectiveness of saving sphincter procedure in the treatment of chronic anal fissure in female patients

INTRODUCTION

Lateral internal sphincterotomy (LIS) is still the approach of choice for the treatment of chronic anal fissure (CAF) regardless to the internal anal sphincter tone but it is burdened by high risk post-operative faecal incontinence (FI). In female patient there are some anatomical and functional differences of the sphinteric system which make them more at risk of FI and vaginal birth could cause sphinteric lesions affecting the anal continence function. The aim of our study is to evaluate the results of saving sphincter procedure as treatment for female patients affected by CAF.

METHODS

We studied 110 female patients affected by CAF undergone fissurectomy and anoplasty with V-Y cutaneous flap advancement associating pharmacological sphincterotomy in patients with hypertonic IAS. The follow up was at least for 2 years. The goals were patient's complete healing, the evaluation of FI, recurrence rate and manometry parameters.

RESULTS

All wounds healed within 40 days after surgery. We recorded 8 cases of recurrences 6 healed with medical therapy and 2 with dilatation. We recorded 2 "de novo" temporary and low grade post-operative cases of FI. Post-operative value of MRP were unmodified in patient with normotonic IAS but significantly lower at 12 months follow up as compared with the pre-operative ones in patients with hypertonic IAS; after 24 months from surgery MRP values were within the normal range.

CONCLUSION

The fissurectomy and anoplasty with V-Y cutaneous flap alone or in association with a pharmacological sphincterotomy in patients with hypertonic IAS may represent an effective approach for the treatment of CAF in female patients.

Menopause, aging and the failing pelvic floor: a clinician's view

The management of pelvic organ disorders is common and challenging work. Nowadays, midlife women are more active than they were in the past, and the development of pelvic organ prolapse (POP) disrupts quality of life and impairs social and personal activities. The aging process and hormonal changes have a role in influencing the structure and function of the lower urinary and genital tract. Correct diagnosis of pelvic organ disorders and the identification of women's symptoms are the hallmarks of tailored management. Treatment is multimodal and multidisciplinary; it requires competence in pelvic medicine and surgery. When conservative treatments fail, women with symptomatic POP are candidates for reconstructive surgery: the optimal management requires clinicians who are familiar with all of the available strategies and who are able to choose the best strategies in a tailored manner. Knowing and understanding the management of POP should be integrated into the practice of health-care professionals dealing in menopause.

Current imaging techniques for evaluation of fistula in ano: a review

Background

Fistula in ano is one of the common anorectal disorders which have a tendency to recur specially in complex cases usually due to missed or undetected sepsis at the time of examination or surgery. A correct identification of the primary source of crypt infection along with a complete understanding of the anatomical course of primary and secondary tracks and abscesses is a prerequisite for the successful management of fistula. Preoperative evaluation of fistula in ano using radio-imaging techniques provides a handy insight of fistula anatomy and helps in planning the appropriate treatment strategy. The objective of this article is to review the role of different radio-imaging techniques in the diagnosis and evaluation of fistula in ano along with their advantages and disadvantages over one another.

Main text

A comprehensive literature review was performed searching through the electronic databases as well as the standard textbooks of colorectal surgery. X-rays (plain radiographs and contrast fistulography), computed tomography (CT) scanning, anal endosonography, and magnetic resonance (MR) imaging are the modalities used for preoperative imaging of fistula in ano. Due to low accuracy, X-ray fistulography is not used now for fistula imaging. CT fistulography can be more accurate in cases associated with acute inflammations and abscesses and the fistulas related with inflammatory bowel disease. Anal endosonography and MRI are two of the mostly used and reliable imaging techniques for fistula in ano. Though the use of a 3D technology has improved the accuracy of anal endosonography, MRI is the preferred choice by many. However, various reports have depicted comparable accuracies for both MRI and anal endosonography showing both to be equally sensitive but MRI to be more specific. 3D endoanal ultrasound, on the other hand, is more rapid and can also be used intraoperatively to provide live imaging during surgical exploration.

Conclusion

Complex and recurrent fistula cases should undergo a preoperative imaging to reduce the chances of recurrence. MRI is recommended as the imaging modality of choice for such cases. 3D anal endosonography may however be a good option over MRI owing to its rapidity, availability, and potential of intraoperative assistance during surgery.

Characteristics of urodynamic study parameters associated with intermediate-term continence after robot-assisted radical prostatectomy in elderly patients

PURPOSE

To investigate the relationship between urodynamic study (UDS) data and recovery of urinary incontinence (UI) in elderly patients who underwent robot-assisted radical prostatectomy (RARP).

MATERIALS AND METHODS

Seventy-five prostate cancer (PCa) patients received UDS before and at 3 months after RARP. They were divided into two groups; a younger group (<70 years old, n = 47) and older group (≥70 years, n = 28), and each was classified according to urinary continence (UC) or UI at 3 months post-RARP. Continence was defined as being pad-free or 1-safety pad usage per day.

RESULTS

In the older group, preoperative maximum urethral closure pressure (MUCP) in the UI group was significantly lower than that in the UC group. Detrusor overactivity (DO) rate was significantly higher in the older UI group than in the older UC group at both pre- and 3 months post-RARP. Persistent DO rate pre- and post-RARP was significantly higher in the older group than in the younger group. Regardless of age, postoperative DO was an independent predictor of UI 6 months post-RARP.

CONCLUSIONS

In elderly patients, low preoperative MUCP and both pre- and postoperative DO are associated with postoperative UI.

Essential anatomy for total mesorectal excision and lateral lymph node dissection, in both trans-abdominal and trans-anal perspective

BACKGROUND AND PURPOSE

Total Mesorectal Excisions (TME) is the standard treatment of rectal cancer. It can be performed under laparoscopic, robotic or transanal approach. Inadvertent injury to surrounding structure like autonomic nerves is avoidable, no matter which approach is adopted. Lateral lymph node dissection (LLND) is a less commonly performed pelvic operation involving dissection in an unfamiliar area to most general surgeons. This article aims to clarify all the essential anatomy related to these procedures.

METHODS

We performed thorough literature search and revision on the pelvic anatomy. Our cases of TME and LLND, under either laparoscopic or transanal approach, were reviewed. We integrated the knowledge from literatures and our own experience. The result was presented in details, together with original figures and intra-operative photos.

MAIN FINDINGS

Anatomy of pelvic fascia, autonomic nerve system, anal canal and sphincter complex are core knowledge in performing TME and LLND.

CONCLUSIONS

Thorough understanding of the pelvic anatomy enables colorectal surgeons to master these procedures, avoid complication and perform extended resection. On the other hand, surgeons can appreciate the complex pelvic anatomy easier by seeing the pelvis in opposite angles (transabdominal and transaanal view).

A missing distal complex of the external and internal anal sphincters: a macroscopic and histologic study using Japanese and German elderly cadavers

The lower margin of the internal anal sphincter (IAS) is considered to lie on a J-shaped, subcutaneous part (SCP) of the external anal sphincter (EAS). The lower IAS is united with the J-shaped SCP to form a smooth-striated muscle complex. In the first part of this study, we ensured the presence of the J-shaped EAS in the lateral wall of the anal canal from 12 near-term fetuses. Second, in the lateral anal wall, the examination of the longitudinal section from 20 male and 24 female Japanese cadavers (72-95 years-old) demonstrated that the J-shaped EAS was lost in 15 (34%) due to the very small SCP. Third, we demonstrated that the J-shaped EAS was restricted in the latera anal wall using longitudinal histological sections of the anal canal from 11 male Japanese cadavers (75-89 years-old). Therefore, a site-dependent difference in the IAS-EAS configuration was evident. Finally, we compared a frequency of the lost J-shape between human populations using 10 mm-thick frontal slices from 36 Japanese and 28 German cadavers. The two groups of cadavers were compatible in age (a 0.2-years' difference in males). The macroscopic observations revealed that the J-shaped EAS was absent from 13 (36%) Japanese and six (20%) German specimens, suggesting that the SCP degeneration occurred more frequent in elderly Japanese than elderly German individuals (p < 0.05). The distal IAS-EAS complex seemed to push residual feces out of the anal canal at a transient phase from evacuation to closure. The absence might be the first sigh of anal dysfunction.

Parity: a risk factor for decreased pelvic floor muscle strength and endurance in middle-aged women

INTRODUCTION AND HYPOTHESIS

The incidence of pelvic floor muscle (PFM) dysfunction increases rapidly with menopause and aging. Despite the raised magnitude and prevalence of pelvic floor disorders in middle-aged women, the risk factors underlying PFM dysfunction still remain to be identified. PFM function can be clinically measured as the maximum strength and endurance using manometry. The aim of this study was to evaluate PFM function in terms of strength and endurance by perineometer and to assess the risk factors that decrease PFM strength and endurance in middle-aged women.

METHODS

This was a cross-sectional study. Overall, 125 parous women (age 40-60 years) completed the study. A questionnaire was used to collect information on several demographic and obstetric variables. The Peritron perineometer measured PFM strength and endurance. Multiple linear regression analysis was used to evaluate the effects of sociodemographic variables on PFM function.

RESULTS

Both average strength of PFMs and maximum muscle strength significantly reduced as the number of parity increased. Average and maximum strength of PFMs showed a significant difference between women with parities of two and one (β = -0.435, p < .001; β = -0.441, p < 0.001, respectively). Both were even more influenced in women with parity of three (β = -0.503, p < .001; β = -0.500, p < .001). However, PFM endurance did not decrease with increasing parity number until the parity of two; however, it decreased in women with parity of three (β = -0.302, p < 0.05).

CONCLUSION

Parity appeared to have a dominant influence on weakness of PFM, and strength was more significantly associated with parity than endurance in middle-aged women.

A PASSIVE STATE SIMULATION OF AN ANAL SPHINCTER USING SIMMECHANICS

Nowadays, different mechanical artificial sphincters can be found implanted in human beings, trying to overcome a deficiency in the performance of the natural one. However, they do not take into account the natural anal sphincter’s (AS) dimensions, and autonomous response; they also lack in basic contraction and relaxation properties. In this paper, by addressing the AS behavior, an AS model designed with Matlab/SimMechanics is shown. The model comprises bodies of concentrated mass interconnected by springs. The mass–spring system is arranged in concentric rings where every concentrated mass is interconnected by a spring. Each spring takes specific stiffness, which varies with length, in accordance to an experimental curve. The system described can be loaded or unloaded, describing then the muscle behavior.

Each element that forms the model of rings is subject to displacements caused by forces of traction and compression, when a radial force is applied from the center towards the inner ring. The springs of the inner ring experience forces of traction, whereas the springs that connect the body of the inner ring with the outer ring perpendicularly are submitted to compression forces.The data used in the proposed model corresponded to dimensions of the humanAS: width, height, rigidity, stress, tension, basically obtaining an initial deformation behavior according to the sphincter in the passive state. The model remained stable with some mechanical oscillations due to the elastic elements; by modifying one of the parameters, the behavior became unstable and unmanageable. It was verified that it is a sensitive model when modifying the initial conditions that the concrete data requires in case of reproducing the sphincter muscle with particular dimensions.

The evaluation of the effect of vaginal delivery and aging on anal sphincter anatomy and function

OBJECTIVE

This study was conducted to evaluate the effect of vaginal delivery and aging on anal sphincter anatomy and function.

METHOD

Asymptomatic thirty women were included in this prospective study. Group 1 included 10 women (age range: 18-50) who had never been pregnant. Group 2 included 10 women (age range: 18-50) who had vaginal delivery. Group 3 included 10 women over 50 who had vaginal delivery.

RESULTS

There was no statistically significant difference between the three groups in terms of resting and squeeze pressures. It was found that sphincter thickness showed statistically significant difference between the group 1 and group 3, and also group 2 and group 3. There was not statistically significant difference between the group 1 and group 2 in terms of sphincter thickness. There was a positive correlation between the age and sphincter thickness in all groups. In terms of sphincter thickness and pressure findings there was a positive correlation between the squeeze pressure and external anal sphincter thickness only in group 3.

CONCLUSION

The vaginal delivery did not have a negative influence on the structure and function of the anal sphincter in asymptomatic women. However, it was found that anal sphincter thickness changed strongly in a positive manner with aging.

MRI of anal canal: normal anatomy, imaging protocol, and perianal fistulas: Part 1

Anal complaints are very common in the general population and are caused by a variety of disorders mostly benign in nature. The aim of this article is to provide the radiologist with a detailed description of the MRI anatomy and technique, and an overview of the various diseases most commonly presenting with anal pain, by descriptions and illustrative examples of MRI features of each entity.

MRI of anal canal: common anal and perianal disorders beyond fistulas: Part 2

A broad spectrum of disease, from benign processes to life-threatening pathologies, can cause anal pain. MR imaging (MRI) has become increasingly widely used method over the past two decades for the evaluation of individuals with anorectal symptoms. Although imaging is rarely necessary to determine the etiology of the majority of cases, MRI is particularly useful as a noninvasive method of excluding severe neoplastic conditions. In this article, MRI findings of a number of pathologies such as anal and perianal neoplasms, hemorrhoidal disease, arteriovenous malformation of the perianal region, and anal sphincter lesions (defects, scarring, atrophy) which may lead to fecal incontinence are presented.

Essential Anatomy of the Anorectum for Colorectal Surgeons Focused on the Gross Anatomy and Histologic Findings

The anorectum is a region with a very complex structure, and surgery for benign or malignant disease of the anorectum is impossible without accurate anatomical knowledge. The conjoined longitudinal muscle consists of smooth muscle from the longitudinal muscle of the rectum and the striate muscle from the levator ani and helps maintain continence; the rectourethralis muscle is connected directly to the conjoined longitudinal muscle at the top of the external anal sphincter. Preserving the rectourethralis muscle without damage to the carvernous nerve or veins passing through it when the abdominoperineal resection is implemented is important. The mesorectal fascia is a multi-layered membrane that surrounds the mesorectum. Because the autonomic nerves also pass between the mesorectal fascia and the parietal fascia, a sharp pelvic dissection must be made along the anatomic fascial plane. With the development of pelvic structure anatomy, we can understand better how we can remove the tumor and the surrounding metastatic lymph nodes without damaging the neural structure. However, because the anorectal anatomy is not yet fully understood, we hope that additional studies of anatomy will enable anorectal surgery to be performed based on complete anatomical knowledge.

Anatomy and mechanical properties of the anal sphincter muscles in healthy senior volunteers

BACKGROUND

A large proportion of age-related fecal incontinence is attributed to weakness or degeneration of the muscles composing the anal continence organ. However, the individual role of these muscles and their functional interplay remain poorly understood.

METHODS

This study employs a novel technique based on the combination of MR imaging and FLIP measurements (MR-FLIP) to obtain anatomical and mechanical information simultaneously. Unlike previous methods used to assess the mechanics of the continence organ, MR-FLIP allows inter-individual comparisons and statistical analysis of the sphincter morpho-mechanical parameters. The anatomy as well as voluntary and involuntary mechanical properties of the anal continence organ were characterized in 20 healthy senior volunteers.

RESULTS

Results showed that the external anal sphincter (EAS) forms a funnel-like shape with wall thickness increasing by a factor of 2.5 from distal (6 ± 0 mm) to proximal (15 ± 3 mm). Both voluntary and involuntary mechanical properties in this region correlate strongly with the thickness of the muscle. The positions of least compliance and maximal orifice closing were both located toward the proximal EAS end. In addition, maximal contraction during squeeze maneuvers was reached after 2 s, but high muscle fatigue was measured during a 7 s holding phase, corresponding to about 60% loss of the energy produced by the muscles during the contraction phase.

CONCLUSIONS

This work reports baseline parameters describing the morpho-mechanical condition of the sphincter muscle of healthy elderly volunteers. New parameters were also proposed to quantify the active properties of the muscles based on the mechanical energy associated with muscle contraction and fatigue. This information could be used to assess patients suffering from AI or for the design of novel implants.

Gender differences in chronic constipation on anorectal motility

BACKGROUND

The epidemiology of chronic constipation (CC) skews toward female predominance, yet men make up an important component of those suffering from CC. We sought to determine whether there are sex-specific differences in symptoms and physiologic parameters on anorectal manometry (ARM).

METHODS

We performed a case-control analysis of sequential men and age-matched women (2:1 ratio) presenting for ARM as part of the evaluation of CC. We collected physiologic parameters derived from 3D high-resolution ARM in addition to the ROME III constipation module and the Pelvic Floor Distress Inventory 20 (PFDI-20) questionnaires. We analyzed univariate, sex-specific differences in ARM physiologic parameters and PFDI-20 parameters and adjusted for putative confounders using multivariate logistic regression.

KEY RESULTS

Our study enrolled 80 men and 165 age-matched women. Men had a higher median sphincter resting pressure (81.2 vs 75.2 mm Hg, P=.01) and mean squeeze pressure (257.0 vs 170.5 mm Hg, P<.0001) than women. Although men reported significantly less severe straining and incomplete evacuation, they had greater mean rectoanal pressure differential (-106.7 vs -71.1 mm Hg, P<.0001), smaller mean defecation index (0.17 vs 0.27, P=.03) and higher volume threshold for urgency (115.2 v. 103.4 mL, P=.03). However, women were more likely to have abnormal balloon expulsion time (BET) than men (52.7% vs 35.0%, P=.01). After multivariate analysis, male gender was the only independent predictor of a normal BET (OR: 0.48, 95% CI: 0.27-0.86, P=.01).

CONCLUSIONS & INFERENCES

Men and women with CC differ with regard to symptom severity and physiologic parameters derived from ARM suggesting differences in their pathophysiology.

Chronic anal fissure: morphometric analysis of the anal canal at 3.0 Tesla MR imaging

OBJECTıVE: To compare the morphometric data relating to the muscular structures of the anal canal, in patients with chronic anal fissure and in control group, examined at a 3.0 Tesla MR system.

SUBJECTS AND METHODS

Forty-seven consecutive patients with chronic anal fissure and randomly selected 40 patients who had no claims for perianal disease during their life time were included in the study. T2-weighted sagittal, high-resolution (HR) T2-weighted, and contrast-enhanced fat-suppressed T1-weighted oblique axial and oblique coronal images were retrospectively analyzed by two observers in consensus. Thickness of sphincteric muscles, anal canal length, anorectal angle, thickness of anococcygeal ligament, depth of Minor triangle, width between subcutaneous sphincters, vascularity of posterior commissure, visibility of posterosuperior projection of external sphincter, and angle between the distal anal canal and posterosuperior projection of external sphincter (H angle) in patients and in controls were compared and analyzed using t test, Mann-Whitney U test, and Spearman correlation.

RESULTS

The patients with chronic anal fissure had longer anal canal (51.50 mm ± 0.91 vs. 44.11 mm ± 0.71; p = 0.000), thicker internal anal sphincter muscle at mid-anal level (4.18 ± 0.15 vs. 3.39 ± 0.07; p = 0.007), and wider space between subcutaneous external sphincters (11.39 ± 0.50 vs. 6.89 ± 0.22; p = 0.000). In patients, there was a positive correlation between H angle and external sphincter thickness at proximal (r = 0.347; p = 0.021), middle (r = 0427; p = 0.000), and distal (r = 0.518; p = 0.000)) levels of the anal canal. CONCLUSıON: 3.0 Tesla MR imaging provides detailed information about the morphometric changes in the anal sphincter muscles in patients with chronic anal fissure.

Gastrointestinal Dysmotility in the Elderly

The number of persons 60 years and older has increased 3-fold between 1950 and 2000. Aging alone does not greatly impact the gastrointestinal (GI) tract. Digestive dysfunction, including esophageal reflux, achalasia, dysphagia, dyspepsia, delayed gastric emptying, constipation, fecal incontinence, and fecal impaction, is a result of the highly prevalent comorbid conditions and the medications with which those conditions are treated. A multidisciplinary approach with the expertise of a geriatrician, gastroenterologist, neurologist, speech pathologist, and physical therapist ensures a comprehensive functional and neurological assessment of the older patient. Radiographic and endoscopic evaluation may be warranted in the evaluation of the symptomatic older patient with consideration given to the risks and benefits of the test being used. Treatment of the digestive dysfunction is aimed at improving health-related quality of life if cure cannot be achieved. Promotion of healthy aging, treatment of comorbid conditions, and avoidance of polypharmacy may prevent some of these digestive disorders. The age-related changes in GI motility, clinical presentation of GI dysmotility, and therapeutic principles in the symptomatic older patient are reviewed here.

Topography and landmarks for the nerve supply to the levator ani and its relevance to pelvic floor pathologies

The aim of this study was to explore the anatomical variations of the nerve to the levator ani (LA) and to relate these findings to LA dysfunction. One hundred fixed human female cadavers were dissected using transabdominal, gluteal, and perineal approaches, resulting in two hundred dissections of the sacral plexus. The pudendal nerve and the sacral nerve roots were traced from their origin at the sacral foramina to their termination. All nerves contributing to the innervation of the LA were considered to be the nerve to the LA. Based on the spinal nerve components, the nerve to the LA was classified into the following categories: 50% (n = 100) originated from S4 and S5 (type I); 19% (n = 38) originated from S5 (type II); 16% (n = 32) originated from S4 (type III); 11% (n = 22) originated from S3 and S4 (type IV); 4% (n = 8) originated from S3, S4, and S5 (type V). Two patterns of nerve termination were observed. In 42% of specimens, the nerve to the LA penetrated the coccygeus muscle and assumed an external position along the inferior surface of the LA muscle. In the remaining 58% of specimens, the nerve crossed the superior surface of the coccygeus muscle and continued along the superior surface of the iliococcygeus muscle. Damage to the nerve to LA has been associated with various pathologies. In order to minimize injuries during surgical procedures, a thorough understanding of the course and variations of the nerve to the LA is extremely important.

Clinical symptoms related to anal sphincter defects and atrophy on external phased-array MR imaging

INTRODUCTION AND HYPOTHESIS

Defecatory complaints have a severe impact on quality of life. The additional value of pelvic floor MRI in patients with defecatory complaints is unclear. Our aim was to correlate the presence of defects and atrophy of the anal sphincter complex using pelvic floor MRI in women with mixed pelvic floor symptoms and to establish patient characteristics and self reported complaints predictive of pathology.

METHODS

This is a retrospective study among women with mixed pelvic floor symptoms who underwent external phased-array MRI and completed a questionnaire on bothersome defecatory complaints. Data on patient characteristics, including obstetrical history and questionnaire scores were correlated with the assessment of anal sphincter defects and atrophy on pelvic floor MRI.

RESULTS

One hundred and fifty-eight women were included. A defect of the external anal sphincter (EAS) and internal anal sphincter (IAS) was found in 18 (11%) and 5 (3%) patients respectively. Atrophy of the EAS was present in 72 patients (46%), with more cases of mild (n = 52, 33%) than severe atrophy (n = 20, 13%). The variable "previous third or fourth degree tear" had a significant positive association with an IAS defect on MRI, with an OR of 9.533 (1.425-63.776). Patients with EAS atrophy had higher scores for fecal incontinence (indicating more bother) than patients without EAS atrophy. Higher age and BMI were true predictors of the presence of more severe EAS atrophy.

CONCLUSION

Atrophy of the EAS was highly prevalent in this population and was associated with bothersome symptoms of fecal incontinence.

Anal sphincter complex: 2D and 3D endoanal and translabial ultrasound measurement variation in normal postpartum measurements

INTRODUCTION AND HYPOTHESIS

Women may experience anal sphincter anatomy changes after vaginal birth (VB) or Cesarean delivery (CD). Therefore, accurate and acceptable imaging options to evaluate the anal sphincter complex (ASC) are needed. ASC measurements may differ between translabial (TLUS) and endoanal (EAUS) ultrasound imaging and between 2D and 3D US. The objective of this analysis was to describe measurement variation between these modalities.

METHODS

Primiparous women underwent 2D and 3D TLUS imaging of the ASC 6 months after VB or CD. A subset of women also underwent EAUS measurements. Measurements included internal anal sphincter (IAS) thickness at proximal, mid, and distal levels and the external anal sphincter (EAS) at 3, 6, 9, and 12 o'clock positions, as well as bilateral thickness of the pubovisceralis muscle (PVM).

RESULTS

There were 433 women presenting for US: 423 had TLUS and 64 had both TLUS and EAUS of the ASC. All IAS measurements were significantly thicker on TLUS than EAUS (all p < 0.01), while EAS measurements were significantly thicker on EAUS (p < 0.01). PVM measurements with 3D or 2D imaging were similar (p > 0.20). On both TLUS and EAUS, there were multiple sites where significant asymmetry existed in left versus right measurements.

CONCLUSIONS

US modality used to image the ASC introduces small but significant changes in measurements, and the direction of the bias depends on the muscle and location being imaged.

Comparison of muscle fiber directions between different levator ani muscle subdivisions: in vivo MRI measurements in women

INTRODUCTION AND HYPOTHESIS

This study describes a technique to quantify muscle fascicle directions in the levator ani (LA) and tests the null hypothesis that the in vivo fascicle directions for each LA subdivision subtend the same parasagittal angle relative to a horizontal reference axis.

METHODS

Visible muscle fascicle direction in the each of the three LA muscle subdivisions, the pubovisceral (PVM; synonymous with pubococcygeal), puborectal (PRM), and iliococcygeal (ICM) muscles, as well as the external anal sphincter (EAS), were measured on 3-T sagittal MRI images in a convenience sample of 14 healthy women in whom muscle fascicles were visible. Mean ± standard deviation (SD) angle values relative to the horizontal were calculated for each muscle subdivision. Repeated measures ANOVA and post-hoc paired t tests were used to compare muscle groups.

RESULTS

Pubovisceral muscle fiber inclination was 41 ± 8.0°, PRM was -19 ± 10.1°, ICM was 33 ± 8.8°, and EAS was -43 ± 6.4°. These fascicle directions were statistically different (p < 0.001). Pairwise comparisons among levator subdivisions showed angle differences of 60° between PVM and PRM, and 52° between ICM and PRM. An 84° difference existed between PVM and EAS. The smallest angle difference between levator divisions was between PVM and ICM 8°. The difference between PRM and EAS was 24°. All pairwise comparisons were significant (p < 0.001).

CONCLUSIONS

The null hypothesis that muscle fascicle inclinations are similar in the three subdivisions of the levator ani and the external anal sphincter was rejected. The largest difference in levator subdivision inclination, 60°, was found between the PVM and PRM.

Anorectal toxicity of external beam radiotherapy in the treatment of prostate cancer

Introduction:

Maximising radiotherapy dosage is associated with better tumour response in prostate cancer. High dose three-dimensional conformal radiotherapy (3D CRT) has allowed dose escalation to be safely achieved and the current standard dose in the UK with this technique is 74 Grays (Gy). Documenting normal tissue tolerance is critical and forms the basis of this prospective study of anorectal toxicity.

Patients and methods:

Seventeen consecutive men (median age 72 (range 50–79) years) with localised or locally advanced prostate cancer treated with 74 Gy of 3D CRT were studied. Wexner incontinence scores, comprehensive anorectal physiology and endoanal ultrasound were measured before and four months after completing treatment.

Results:

Wexner incontinence scores increased from a median of 0 to 1 (range 0–6) with treatment ( p=0.001). Patients developed faecal urgency (7/17), passive faecal loss (5/17) or a combination of both (3/17) as new anorectal symptoms. No patients reported episodes of frank faecal incontinence. A significant decline in rectal mucosal electrosensitivity (mean (standard deviation (SD)) thresholds increasing from 24.7 (10.7) to 34.3 (9.3) mA after treatment, p=0.003) and an increase in rectal elastance (mean (SD) of 0.056 (0.03) mm Hg/ml to 0.078 (0.036) mm Hg/ml pre- and post-treatment respectively, p=0.0181) was seen. No changes in anal canal manometry, rectal distension volumes and endoanal ultrasound were noted.

Conclusions:

Early anorectal symptoms are common after 3D CRT for prostate cancer. Rectal injury is evident with an increase in wall stiffness and a decrease in mucosal sensitivity. Longer term studies monitoring anorectal toxicity are warranted.

Postpartum translabial 2D and 3D ultrasound measurements of the anal sphincter complex in primiparous women delivering by vaginal birth versus Cesarean delivery

INTRODUCTION AND HYPOTHESIS

Consensus on normal translabial ultrasound (TL-US) anal sphincter complex measurements for postpartum women is lacking. We aimed to evaluate normative measurements in 2D and 3D TL-US for the anal sphincter complex (ASC) at 6 months postpartum and compare these measurements in women who had a vaginal birth (VB) and in those who had a Cesarean delivery (CD).

METHODS

A large, prospective cohort of primiparous women underwent 2D and 3D TL-US 6 months after their first delivery. For normative sphincter measurements, we excluded women with third- or fourth-degree lacerations or with sphincter interruption on TL-US. Measurements included the sphincter thickness at the 3, 6, 9, and 12 o'clock positions of the external anal sphincter (EAS) and the internal anal sphincter (IAS) at proximal, mid, and distal levels. We also measured the mean coronal diameter of the pubovisceralis muscle (PVM).

RESULTS

696 women consented to participate, and 433 women presented for ultrasound imaging 6 months later. Women who sustained a third- or fourth-degree laceration had significantly thicker EAS measurements at 12 o'clock. Sphincter asymmetry was common (69 %), but was not related to mode of delivery. Only IAS measurements at the proximal and distal 12 o'clock position were significantly thicker for CD patients. There were no significant differences in the EAS or PVM measurements between VB and CD women.

CONCLUSIONS

There appear to be few differences in normative sphincter ultrasound measurements between primiparous patients who had VB or CD.

Effect of vaginal delivery and ageing on the anatomy of the female anal canal assessed by three-dimensional anorectal ultrasound

AIM

The effect of vaginal delivery and ageing on the anatomy of the anal canal was assessed using three-dimensional anorectal ultrasound to determine the interobserver reliability.

METHOD

One-hundred and eighteen asymptomatic women without sphincter damage were grouped according to parity and mode of delivery. They were then stratified by age (≤50 years vs >50 years). Group I consisted of 35 nulliparous women, of mean ages 36 years (n = 20) and 62 years (n = 15), Group II consisted of multiparous women, having one or more vaginal deliveries (n = 43), of mean ages 43 years (n = 20) and 60 years (n = 23) and Group III consisted of women who had a Caesarean section (n = 40) of mean ages 41 years (n = 20) and 56 years (n = 20). The groups were compared with regard to the length and the thickness of the external anal sphincter, the internal anal sphincter, the posterior external sphincter and the puborectalis in all quadrants and the anterior gap. Interobserver variability was assessed.

RESULTS

In women having vaginal delivery the length of the anterior external sphincter was shorter (P = 0.0004) and the gap was longer (P = 0.0306). The external sphincter tended to be thinner in individuals having vaginal delivery (P = 0.0677) and in those subjects over 50 years of age having had a vaginal delivery (P = 0.0164). In nulliparous women, the internal sphincter was thicker in subjects over 50 years of age (P = 0.0229). The intraclass correlation coefficient was 0.755-0.916 for sphincter muscle and gap length and 0.446-0.769 for muscle thickness.

CONCLUSION

Vaginal delivery was associated with a shorter anterior external sphincter, a longer gap and a thinner anterior external sphincter in asymptomatic women. Age was correlated with sphincter thickness, and nulliparous women >50 years of age had a thicker internal sphincter. Three-dimensional ultrasound was found to be a reliable method for measuring anal structures.

Should we care about the internal anal sphincter?

The internal anal sphincter is currently regarded as a significant contributor to continence function. Four physiological and morphological aspects of the internal anal sphincter are presented as part of the current evidence base for its preservation in anal surgery. 1) The incidence of continence disturbance following deliberate internal anal sphincterotomy is underestimated, although there is presently no prospective imaging or physiologic data supporting the selective use of sphincter-sparing surgical alternatives. 2) Given that the resting pressure is a measure of internal anal sphincter function, its physiologic representation (the rectoanal inhibitory reflex) shows inherent differences between incontinent and normal cohorts which suggest that internal anal sphincter properties act as a continence defense mechanism. 3) Anatomical differences in distal external anal sphincter overlap at the point of internal anal sphincter termination may preclude internal anal sphincter division in some patients where the distal anal canal will be unsupported following deliberate internal anal sphincterotomy. 4) internal anal sphincter-preservation techniques in fistula surgery may potentially safeguard postoperative function. Prospective, randomized trials using preoperative sphincter imaging and physiologic parameters of the rectoanal inhibitory reflex are required to shape surgical decision making in minor anorectal surgery in an effort to define whether alternatives to internal anal sphincter division lead to better functional outcomes.

Diffusion tensor imaging of the anal canal at 3 tesla: feasibility and reproducibility of anisotropy measures

PURPOSE

To assess the feasibility and reproducibility of 3-tesla diffusion tensor imaging (DTI) of the anal canal.

MATERIALS AND METHODS

DTI was performed in 25 men with no clinical history of anal canal disease undergoing MRI for prostate cancer. Analysis of fractional anisotropy (FA), relative anisotropy (RA), and apparent diffusion coefficient (ADC) were determined for the epithelial/subepithelial layer, internal sphincter, external sphincter, and puborectalis. The directionality of diffusion was recorded from color-coded tractography maps. Obturator internus and gluteus maximus served as reference muscles. Mean (SD) of values for FA, RA, and ADC were compared using analysis of variance. Intra and inter-rater agreement and test reproducibility (n = 5) was assessed by Bland-Altman statistics.

RESULTS

Mean (SD) for the epithelial/subepithelial layer, internal, external sphincter, and puborectalis were as follows: FA: 0.283 (0.099); 0.337 (0.049); 0.415 (0.072); and 0.407 (0.062), respectively. RA: 0.241 (0.094); 0.292 (0.050); 0.371 (0.083); 0.361 (0.067), respectively; and ADC: 1.49 (0.23); 1.59 (0.19); 1.51 (0.28); and 1.54 (0.29) × 10(-3) mm(2) /s, respectively. Good overall intra and inter-rater agreement and test-retest reproducibility was noted (coefficient of variation of 4.8-19.4% and 5.9-12.9%, respectively).

CONCLUSION

Anisotropy is evident in the anal canal with good inter-rater agreement and test reproducibility.

Endoanorectal ultrasonography

Endoanorectal ultrasonography (EARUS) may be used for diagnosing various anorectal disorders. EARUS is easy to perform, has a short learning curve, and causes less discomfort than routine digital examination. Anal sphincters can be clearly visualized, and one can easily distinguish between the internal (hypoechoic) and external (hyperechoic) anal sphincters. Other pelvic floor structures, like the puborectalis muscle, can also be visualized. The use of contrast agents can increase the accuracy of EARUS in the assessment of perianal fistulae. In addition, EARUS is an excellent alternative to expensive magnetic resonance imaging. Besides its use in incontinence and perianal sepsis, the presence of slight or massive submucosal invasion in early rectal cancer may be imaged in greater detail. With 3-dimensional EARUS, it is possible to diagnose the anorectal diseases, in multiplane, with high spatial resolution, adding important information about the therapeutic decision. The normal sonographic anatomy of the anorectum, sonographic findings of anorectal diseases, and indications and limitations of endosonography with complementary techniques such as transvaginal and transperineal ultrasound are reviewed in this article.

Functional morphology of anal sphincter complex unveiled by high definition anal manometery and three dimensional ultrasound imaging

BACKGROUND

Anal sphincter complex consists of anatomically overlapping internal anal sphincter (IAS), external anal sphincter (EAS) and puborectalis muscle (PRM). We determined the functional morphology of anal sphincter muscles using high definition anal manometery (HDAM), three dimensional (3D)-ultrasound (US) and Magnetic resonance (MR) imaging.

METHODS

We studied 15 nulliparous women. High definition anal manometery probe equipped with 256 pressure transducers was used to measure the anal canal pressures at rest and squeeze. Lengths of IAS, PRM, and EAS were determined from the 3D-US images and superimposed on the HDAM plots. Movements of anorectal angle with squeeze were determined from the dynamic MR images.

KEY RESULTS

High definition anal manometery plots reveal that anal canal pressures are highly asymmetric in the axial and circumferential direction. Anal canal length determined by the 3D-US images is slightly smaller than that measured by HDAM. The EAS (1.9 ± 0.5 cm long) and PRM (1.7 ± 0.4 cm long) surround distal and proximal parts of the anal canal, respectively. With voluntary contraction, anal canal pressures increase in the proximal (PRM) and distal (EAS zone) parts of anal canal. Posterior peak pressure in the anal canal moves cranially in relation to the anterior peak pressure, with squeeze. Similar to the movement of peak posterior pressure, MR images show cranial movement of anorectal angle with squeeze.

CONCLUSIONS & INFERENCES

Our study proves that the PRM is responsible for the closure of the cranial part of anal canal. HDAM, in addition to measuring constrictor function can also record the elevator function of levator ani/pelvic floor muscles.

Gastrointestinal issues in the older female patient

As the body ages, it undergoes a multitude of changes. Some of these changes are visible, whereas others are not and may be elicited during the patient encounter. Some gastrointestinal issues may be more common in the elderly population and possibly in older women. These issues range from motility disorders, such as fecal incontinence and constipation, to changes in neuropeptide function and its effect on the anorexia of aging. This article comprehensively reviews gastrointestinal issues that commonly afflict the elderly female population.

Feasibility of diffusion tensor imaging (DTI) with fibre tractography of the normal female pelvic floor

Objectives

To prospectively determine the feasibility of diffusion tensor imaging (DTI) with fibre tractography as a tool for the three-dimensional (3D) visualisation of normal pelvic floor anatomy.

Methods

Five young female nulliparous subjects (mean age 28 ± 3 years) underwent DTI at 3.0T. Two-dimensional diffusion-weighted axial spin-echo echo-planar (SP-EPI) pulse sequence of the pelvic floor was performed, with additional T2-TSE multiplanar sequences for anatomical reference. Fibre tractography for visualisation of predefined pelvic floor and pelvic wall muscles was performed offline by two observers, applying a consensus method. Three eigenvalues (λ1, λ2, λ3), fractional anisotropy (FA) and mean diffusivity (MD) were calculated from the fibre trajectories.

Results

In all subjects fibre tractography resulted in a satisfactory anatomical representation of the pubovisceral muscle, perineal body, anal - and urethral sphincter complex and internal obturator muscle. Mean FA values ranged from 0.23 ± 0.02 to 0.30 ± 0.04, MD values from 1.30 ± 0.08 to 1.73 ± 0.12 × 10⁻³ mm²/s. Muscular structures in the superficial layer of the pelvic floor could not be satisfactorily identified.

Conclusions

This study demonstrates the feasibility of visualising the complex three-dimensional pelvic floor architecture using 3T-DTI with fibre tractography. DTI of the deep female pelvic floor may provide new insights into pelvic floor disorders.

MRI anatomy of the anal region

PURPOSE

The aim of this study was to identify the normal anatomy of the anal region on magnetic resonance images.

METHODS

T1-weighted turbo spin-echo images of anal sagittal sections, anal coronal sections, and oblique anal transverse planes were obtained with a body coil in 60 normal volunteers (30 women and 30 men, aged 19-25 years) at rest in the supine position.

RESULTS

T1-weighted images showed fat spaces and muscles simultaneously, allowing visualization of 7 image layers, including the mucosa, submucosa, anal smooth muscle, inner (intersphincteric) space, vertical levator, outer (intersphincteric) space, and external anal sphincter. The anal smooth muscle was derived from the rectal smooth muscle, and the inner space originated from the perirectal space. The outer space lay between the vertical levator and the external sphincters. The puborectalis did not have a longitudinal portion. The deep, superficial, and SC sphincters were 3 separate muscle bundles. The perianal spaces had a complex interconnection.

CONCLUSIONS

Multiplanar body-coil MRI studies can show anorectal fat spaces and musculature simultaneously, allowing fat spaces and musculature to serve as mutual referents. The results of imaging of the anal region with this method are different from previous imaging descriptions and may provide a more accurate and systemic description of the anal region structures than was previously available.

Development of the external anal sphincter with special reference to intergender difference: observations of mid-term fetuses (15-30 weeks of gestation)

To investigate intergender differences in muscle cleavage and joining during development of the external anal sphincter (EAS), we examined semiserial sections of 16 fetuses between 15 and 30 weeks of gestation (6 males and 10 females). The subcutaneous part of the EAS (EASsc) developed along the male perineal raphe and extended posteriorly. Thus, the male EAS was characterized by anterior protrusion of the subcutaneous muscle, in contrast to the almost circular female EAS. In both genders, the bulbospongiosus anlage (or the levator ani anlage) issued muscle fibers to form the superficial (or deep) part of the EAS. The EASsc communicated with the superficial part in males, whereas the female bulbospongiosus tended to communicate with the levator ani rather than the EAS. In both genders, the longitudinal muscle bundle(s) of the anorectum contributed to perineal body formation. However, the male perineal body also had a thick fascia between the rhabdosphincter and the levator. The bulbospongiosus seems to play a critical role in forming the EAS. A strict intergender difference in subcutaneous muscle development is evident along the perineal raphe, as the raphe is not evident in females. These results help to explain variations in the EAS, including anal malformations.

Anorectal and pelvic floor anatomy

The anorectum and pelvic floor are crucial in maintaining continence, facilitating evacuation, providing pelvic organ support while in females the pelvic floor is part of the birth canal. The anal sphincter is a multilayered cylindrical structure, including the smooth muscle internal sphincter and the outer striated muscle layer. The latter comprises the external sphincter as lower outer half and puborectalis as upper outer half of the sphincter. The external sphincter is continuous with the rectum at the anorectal junction. The pelvic floor constitutes four principal layers: endopelvic fascia, the muscular pelvic diaphragm (commonly referred to as levator plate), the perineal membrane (urogenital diaphragm) and the superficial transverse perineii. Anorectum and pelvic floor have multiple interconnections by fascia and ligaments as well as multiple indirect connections to the bony pelvis. Other structures as perineal body and a fibro-elastic network add to this support.

Imaging pelvic floor dysfunction

Pelvic floor function and structure are complex, and imaging (integrated with an understanding of physiology) is central to guiding the clinician in managing patients with incontinence, constipation, difficult rectal evacuation and pelvic organ prolapse. Multimodal imaging techniques such as static and dynamic imaging techniques (sometimes combined in a single sitting) have revolutionised our understanding of functional anatomy. The advent of endo-luminal imaging has increased our spatial resolution by its closer proximity to the area of interest. Dynamic imaging gives us a near physiological data set which helps us to simulate what is likely to happen in real life and gives us a better understanding of the multifactorial causes, and consequences, of pelvic floor dysfunction.

Sonographic imaging of the puborectalis

INTRODUCTION

The aim of the present study was to compare the appearance of the normal male puborectalis using transrectal ultrasound with anatomy examinations to enhance the understanding of the relationship of the prostate to the adjacent pelvic floor. This information may help prevent damage to the puborectalis during transperineal ultrasound-guided biopsies and interventional therapies.

METHODS

Ten formalin-fixed cadavers were dissected to examine the appearance and structure of the puborectalis and its relationship with the peripheral organs. The puborectalis was also observed in a fresh male cadaver using transrectal ultrasound. In the fresh male cadaver, the puborectalis was located using transrectal sonography, the muscle was confirmed by anatomy, and the thickness was measured.

RESULTS

The ultrasonographic observations of the location of the puborectalis were confirmed by anatomy for the fresh cadaver. Bilateral, symmetrical, hypoechoic strips were observed beside the prostate in cross-section, and strip fibers were observed in the longitudinal section. The right and left puborectalis thickness measurements were 6.1 and 6.2 mm, respectively, in the sonographic image, and the measurements were 5.85 and 5.89 mm, respectively, in the formalin-fixed fresh cadaver.

CONCLUSIONS

Transrectal ultrasound provides a new imaging method to observe the male puborectalis, establishing a foundation for recognizing pelvic floor abnormalities with ultrasonography in the future.

Correlation between gross anatomical topography, sectional sheet plastination, microscopic anatomy and endoanal sonography of the anal sphincter complex in human males

This study elucidates the structure of the anal sphincter complex (ASC) and correlates the individual layers, namely the external anal sphincter (EAS), conjoint longitudinal muscle (CLM) and internal anal sphincter (IAS), with their ultrasonographic images. Eighteen male cadavers, with an average age of 72 years (range 62-82 years), were used in this study. Multiple methods were used including gross dissection, coronal and axial sheet plastination, different histological staining techniques and endoanal sonography. The EAS was a continuous layer but with different relations, an upper part (corresponding to the deep and superficial parts in the traditional description) and a lower (subcutaneous) part that was located distal to the IAS, and was the only muscle encircling the anal orifice below the IAS. The CLM was a fibro-fatty-muscular layer occupying the intersphincteric space and was continuous superiorly with the longitudinal muscle layer of the rectum. In its middle and lower parts it consisted of collagen and elastic fibres with fatty tissue filling the spaces between the fibrous septa. The IAS was a markedly thickened extension of the terminal circular smooth muscle layer of the rectum and it terminated proximal to the lower part of the EAS. On endoanal sonography, the EAS appeared as an irregular hyperechoic band; CLM was poorly represented by a thin irregular hyperechoic line and IAS was represented by a hypoechoic band. Data on the measurements of the thickness of the ASC layers are presented and vary between dissection and sonographic imaging. The layers of the ASC were precisely identified in situ, in sections, in isolated dissected specimens and the same structures were correlated with their sonographic appearance. The results of the measurements of ASC components in this study on male cadavers were variable, suggesting that these should be used with caution in diagnostic and management settings.

Correlative anatomy of the anus and rectum

An overview of the normal anatomy of the anus and rectum is provided with an emphasis on correlative imaging, including computed tomography, magnetic resonance, and ultrasound. The major clinically important structures that can be assessed with these imaging modalities are reviewed.

Interobserver and intraobserver variation of two-dimensional and three-dimensional anal endosonography in the evaluation of recurrent anal cancer

PURPOSE

This study was designed to evaluate the interobserver and intraobserver agreement of two-dimensional (2-D) and three-dimensional (3-D) anal endosonography for the detection of local recurrence anal carcinoma.

METHODS

Thirty-six patients were treated for anal carcinoma, and seven had recurrent disease. They were investigated by using 3-D endosonography at Rigshospitalet from July 2001 to January 2005 because of suspected local recurrence. The 3-D endosonographic examinations were reviewed from the hard disc by two observers who twice reviewed all 2-D examinations (the axial projection) as well as all 3-D examinations (the axial, as well as the reconstructed coronal and sagittal projections). The observers scored each examination according to the following scale regarding presence of local recurrence: 1 = no finding/benign findings; 2 = properly benign findings; 3 = suspicious findings/malignant findings. Kappa statistic-statistic was used to evaluate interobserver and intraobserver variation.

RESULTS

Three-dimensional endosonography achieved better interobserver agreement than 2-D endosonography: kappa 3-D 0.34-047 vs. kappa 2-D 0.15-0.28 and better intraobserver agreement: kappa 3-D 0.34-0.62 vs. kappa 2-D 0.22-0.28. These differences showed P < 0.05.

CONCLUSIONS

Three-dimensional endosonography proved to have significantly better interobserver and intraobserver agreement than 2-D endosonography concerning detection of recurrent anal cancer. Three-dimensional endosonography seems to be less dependent of the individual examiner than 2-D endosonography.

Three-dimensional endoanal ultrasonography: intraobserver and interobserver agreement using scoring systems for classification of anal sphincter defects

OBJECTIVES

To determine the degree of intraobserver and interobserver agreement for an experienced and an inexperienced sonologist using two scoring systems for ultrasonographic assessment of anal sphincter defects.

METHODS

The study sample comprised the datasets of all women aged between 20 and 40 years who had attended our outpatient clinic and undergone a complete three-dimensional (3D) endoanal ultrasound (EAUS) examination in the period from January 2003 to December 2005. The EAUS datasets were assessed twice independently by two sonologists: one with experience of > 400 3D EAUS assessments and one inexperienced sonologist who had performed approximately 50 assessments before the study. Cases with intraobserver disagreement were resolved by a third (final) assessment. The final assessment from each observer was used to determine the degree of interobserver agreement. Sphincter defects were classified according to our EAUS defect score and the Starck score.

RESULTS

EAUS datasets of 55 women were included. Based on first vs. second assessments, intraobserver agreement for the experienced sonologist was good for our EAUS defect score (weighted kappa, 0.75) and the Starck score (weighted kappa, 0.73). Intraobserver agreement for the inexperienced sonologist was moderate for our EAUS defect score (weighted kappa, 0.58) and good for the Starck score (weighted kappa, 0.62). Interobserver agreement was good for both our EAUS defect score (weighted kappa, 0.65) and the Starck score (weighted kappa, 0.74).

CONCLUSIONS

Intraobserver and interobserver agreement was acceptable for both scoring systems. The experienced sonologist obtained a higher degree of intraobserver agreement than did the inexperienced sonologist.