Extragenital testing increases case detection of gonorrhea and chlamydia: The impact of implementing nucleic acid amplification testing

Background

Nucleic acid amplification testing (NAAT) was validated in Ontario in 2018 to test for chlamydia and gonorrhea at extragenital (pharyngeal, rectal) sites. Prior to this validation, extragenital testing could be done only by culture in Ontario. The objective of this study was to determine the number and proportion of gonorrhea and chlamydia cases that were detected exclusively through extragenital (pharyngeal and/or rectal) testing after the implementation of extragenital NAAT for these two infections at Sexual Health Clinic among gay, bisexual, and other men who have sex with men (gbMSM).

Methods

Case and laboratory data from before and after NAAT implementation were used to compare the rates of diagnosis of gonorrhea and chlamydia among gbMSM who presented at Sexual Health Clinics and the percent increase in diagnoses in gbMSM in the entire population.

Results

Among gbMSM seen at the clinic after implementation of NAAT testing, 70% of gonorrhea cases and 65% of chlamydia cases were detected exclusively at extragenital sites, corresponding to a four and two-fold increase, respectively, in the average annual number of cases diagnosed. As well, although approximately 50% more pharyngeal than rectal testing occurred, a higher proportion of chlamydia cases were detected rectally than would have been expected; this was not the case for gonorrhea, where most infections were pharyngeal.

Conclusion

It is important that clinicians perform extragenital testing among gbMSM who have sexual contact involving extragenital sites with more than one partner.

A Case of Pneumatic Rectal Perforation Caused by Compressed Air

Rectal perforation is a rare cause of acute abdomen. The most common cause of rectal perforation is trauma. Barotrauma due to the injection of compressed air in the rectum is an extremely rare cause of rectal perforation. We report a case of extensive pneumoperitoneum with abdominal compartment syndrome caused by rectal perforation secondary to the forceful injection of compressed air through the perineum. The patient was successfully managed by immediate relief of abdominal compartment syndrome by needle decompression followed by surgical repair of rectal perforation.

Investigation of Bowel Function with Anorectal Manometry in a Rat Spinal Cord Contusion Model

Bowel dysfunction after chronic spinal cord injury (SCI) is a common source of morbidity and rehospitalization. Typical complications include constipation, fecal impaction, incontinence, abdominal distention, autonomic dysreflexia, and the necessity of interventions (i.e., suppositories, digital stimulation) to defecate. Numerous surveys have confirmed that the remediation of bowel complications is more highly valued for quality of life than improvements in walking. Much of what is known about bowel function after SCI for diagnosis and research in humans has been gained using anorectal manometry (ARM) procedures. However, ARM has been underutilized in pre-clinical animal work. Therefore, a novel combination of outcome measures was examined in the current study that incorporates functional output of the bowel (weekly fecal measurements), weight gain (pre-injury to terminal weight), and terminal ARM measurement with external anal sphincter electromyography under urethane anesthesia. The results indicate higher fecal output after contusion during the sub-acute period (4-7 days) post-injury, changes in the composition of the feces, and functionally obstructive responses in a specific section of the rectum (increased baseline pressure, increased frequency of contraction, and reduced ability to trigger a giant contraction to a distension stimulus). These results demonstrate significant bowel dysfunction in the rodent SCI contusion model that is consistent with data from human research. Thus, the combined measurement protocol enables the detection of changes and can be used, with minimal cost, to assess effectiveness of therapeutic interventions on bowel complications.

Risk of rectal puncture due to needle entry into the presacral space: Importance of measuring the distance between the rectum and sacrococcyx, and the thickness of the sacrococcyx

During ganglion impar block, the needle may approach the presacral space and the sacrum may be penetrated during caudal anesthesia. Because the rectum is in front of the sacrococcyx and is thus at risk for puncture, it is important to determine the distance between the sacrococcyx and rectum, as well as the thickness of the sacrococcyx.Computed tomography was used to measure the distance between the rectum and sacrococcyx, as well as the thickness of the sacrococcyx. The distances between the coccyx and rectum, sacrococcygeal joint and rectum, sacral level 5 ('sacrum 5') and rectum, and 'sacrum 4 to 5 junction' and rectum were measured. The results were compared based on the presence or absence of stools in the rectum. The thickness of the sacrococcyx was measured at the sacrum 4 to 5 junction and sacrococcygeal joint.In total, 1264 patients were included in this study. All distances were less than 1 mm in both males and females, with the exception of the distance between the coccyx and rectum in males. In both males and females, there was no significant difference in distance between the sacrococcyx and rectum according to the presence or absence of feces in the rectum, but there was a difference in the distance between sacrum 5 and the rectum in males (P = .048). Several male and female patients showed thicknesses of less than 5 mm at the sacrococcygeal joint.Some patients have a distance of less than 1 mm between the sacrum and rectum. Practitioners should exercise caution when applying a needle to the presacral space. If the sacrum is accidentally penetrated during caudal block, rectum puncture cannot be ruled out. Excretion of feces does not influence the distance between the sacrococcyx and rectum in females.

Primary signet ring cell carcinoma with tubular adenoma of the rectum: A case report and a review of the literature

RATIONALE

Among the various forms of colorectal carcinomas, primary signet ring cell carcinoma (SRCC) of rectum is infrequent. Primary SRCC with adenoma is even rarer. Due to its low morbidity and lack of obvious manifestations at early stages, it is difficult to make an early diagnosis and perform surgical intervention in time. Herein, we reported a case of primary SRCC with tubular adenoma of rectum and also performed a review of the literature of such cases, in hopes of expanding the general understanding regarding such cases.

PATIENT CONCERNS

A 61-year-old male patient presented with rectal bleeding for 1 week.

DIAGNOSES

A neoplasm could be palpated through a rectal examination, with a size of 4.0 cm by 3.0 cm, at a distance of 5 cm from the anal edge. Magnetic resonance imaging examination and colonoscopies were performed to confirm the finding, and 4 tissue specimens were obtained for histopathologic biopsy. The result of biopsy was high-grade intraepithelial neoplasia with an adenoma component.

INTERVENTIONS

Surgical resection was performed, and histopathologic and immunohistochemical staining examination of the resection confirmed the diagnosis of SRCC with tubular adenoma.

OUTCOMES

The patient was discharged from hospital 12 days postsurgery, without any complications. Further chemotherapy and supportive treatments were suggested to him and will be followed at a local hospital.

LESSONS

Primary rectal SRCC has a rather low morbidity. Furthermore, a rectal SRCC with adenoma which was presenting in this case is even more rare. Besides lack of clinical characters, delay of diagnosis and treatment frequently occur. So far, a surgical procedure has still been one of the most effective treatments. Considering of metastasis and the poor prognosis, early diagnosis, in-time radical resection, and a comprehensive followed treatment are recommended for a higher 5-year overall survival.

Increased incidence of early onset colorectal adenocarcinoma is accompanied by an increased incidence of rectal neuroendocrine tumors

Recent studies have reported an increasing incidence of early onset colorectal cancer (CRC). Few studies compared the changing incidence of CRC by the major histological type, adenocarcinoma and neuroendocrine tumors (NETs). Using data from the Surveillance, Epidemiology, and End Results Program (SEER), we identified CRC from 1992 to 2015 with site and histological codes. Standardized incidence rates of CRC by anatomical locations (proximal, distal and rectal colon) and histological types (adenocarcinoma, NETs and others) were calculated over calendar years. Annual percent changes (APC) and joint-point regression were further computed. A significant increase of cancers in the distal colon and rectum was observed in young populations (20-44 and 45-54 years) but not in the proximal colon. Further analyses found that the highest rise of rectal NETs was in the 45-54 years which contributed 53.47% to the total increase of rectal cancer. The APCs for NETs in the rectum were 2.9 (95% CI: -0.1, 6.0) and 6.1 (95% CI: 3.8-8.4) for 20-44 years or 45-54 years respectively. The increase of NETs in the rectum was still significant in the older than 55 years (APC=3.7, 95% CI: 2.8-4.7), although the total CRC in this group was decreasing. Incidence of NETs in the distal colon is not apparently changing. The increase of CRC incidence among young populations (age < 55) is mainly due to the increased incidence in the rectum and distal colon. Moreover, the increase of early onset cancer in the rectum could be ascribed to increased incidence of adenocarcinoma and NETs.

Plasma protein expression differs between colorectal cancer patients depending on primary tumor location

Colorectal cancer (CRC) includes tumors in the right colon, left colon, and rectum, although they differ significantly from each other in aspects such as prognosis and treatment. Few previous mass spectrometry-based studies have analyzed differences in protein expression depending on the tumor location. In this study, we have used mass spectrometry-based proteomics to analyze plasma samples from 83 CRC patients to study if differences in plasma protein expression can be seen depending on primary tumor location (right colon, left colon, or rectum). Differences were studied between the groups both regardless of and according to tumor stage (II or III). Large differences in plasma protein expression were seen, and we found that plasma samples from patients with rectal cancer separated from samples from patients with colon cancer when analyzed by principal component analysis and hierarchical clustering. Samples from patients with cancer in the right and left colon also tended to separate from each other. Pathway analysis discovered canonical pathways involved in lipid metabolism and inflammation to be enriched. This study will help to further define CRC as distinct entities depending on tumor location, as shown by the widespread differences in plasma protein profile and dysregulated pathways.

Posterior rectal pouch after large full-thickness disc excision of deep endometriosis infiltrating the low/mid rectum and relationship with digestive functional outcome

INTRODUCTION

The aim of our study is to describe MRI appearance of a posterior rectal pouch (PRP) for patients managed for low rectal endometriosis by large full-thickness disc excision and to assess its relationship with postoperative functional digestive symptoms.

MATERIAL AND METHODS

Single center retrospective study including patients managed by low/mid rectal disc excision using a semi-circular stapler (the Rouen technique) from June 2009 to October 2016. Intraoperative findings and data provided by standardized gastrointestinal self-questionnaires (GIQLI, KESS, Wexner and Bristol), before and 1 year after the surgery, were prospectively recorded. Postoperative pelvic MRI were reviewed and PRP was assessed in three planes and its volume was estimated on a 3D T2 weighted sequence.

RESULTS

Eighteen patients were included in the study. All patients had postoperative PRP while none of them presented with rectal stenosis. The mean (± SD) volume of the PRP was estimated at 66 ± 32 mL. The mean antero-posterior diameter was 56 mm ± 22 mm, mean height at 44 mm ± 15 mm and mean width at 46 mm ± 11 mm. No positive correlation between the volume of the PRP and the GIQLI questionnaire was found at one year after surgery (r = -0.24, 95%CI -0.51-0.69, p = 0.44).

CONCLUSION

Large disc excision of low and mid rectum leads to a posterior rectal pouch, with no significant impact on postoperative functional digestive outcomes, but it is not followed by bowel stenosis.

Deep learning-based classification of rectal fecal retention and analysis of fecal properties using ultrasound images in older adult patients

AIM

The present study aimed to analyze the use of machine learning in ultrasound (US)-based fecal retention assessment.

METHODS

The accuracy of deep learning techniques and conventional US methods for the evaluation of fecal properties was compared. The presence or absence of rectal feces was analyzed in 42 patients. Eleven patients without rectal fecal retention on US images were excluded from the analysis; thus, fecal properties were analyzed in 31 patients. Deep learning was used to classify the transverse US images into three types: absence of feces, hyperechoic area, and strong hyperechoic area in the rectum.

RESULTS

Of the 42 patients, 31 tested positive for the presence of rectal feces, zero were false positive, zero were false negative, and 11 were negative, indicating a sensitivity of 100% and a specificity of 100% for the detection of rectal feces in the rectum. Of the 31 positive patients, 14 had hard stools and 17 had other types. Hard stool was detected by US findings in 100% of the patients (14/14), whereas deep learning-based classification detected hard stool in 85.7% of the patients (12/14). Other stool types were detected by US findings in 88.2% of the patients (15/17), while deep learning-based classification also detected other stool types in 88.2% of the patients (15/17).

CONCLUSIONS

The results showed that US findings and deep learning-based classification can detect rectal fecal retention in older adult patients and distinguish between the types of fecal retention.

The median sacral artery in rectal blood supply: A cadaveric study

INTRODUCTION

Insufficient blood supply to the posterior rectal remnant after proctectomy is a possible mechanism for anastomotic leakage. The median sacral artery (MSA) is not generally considered to participate in the rectal blood supply, although some case studies have reported the rectum being supplied by it. The aim of this study is to elucidate the anatomy of the MSA in relation to the posterior rectal wall.

METHODS

Nineteen embalmed cadavers (12 males, seven females; mean age: 76 ± 9 years) were injected with a colored radio-opaque mixture in the aortic bifurcation, radiographed and subsequently dissected along the sacrum. The relationship between the MSA and the rectum was observed and the diameter of the MSA was measured 2 cm below the aortic bifurcation.

RESULTS

MSAs were identified in 16 (84.2%) of the 19 cadavers. Nine MSAs (47.4%) reached the rectal wall and penetrated it. MSAs that reached the posterior rectum took two different routes in the presacral space. Dissection and radiography showed four penetrating MSAs (21.1%) ending in a branching pattern and five (26.3%) as a tapering vessel. Seven MSAs (36.8%) did not reach the rectal wall. The mean MSA diameter was 1.98 ± 0.12 mm.

CONCLUSIONS

Almost half the MSAs reached and penetrated the posterior rectal wall, suggesting possible participation in the rectal blood supply. A large portion of the MSAs that penetrate the rectal wall run outside surgical margins and could continue to provide blood supply to the rectal remnant, potentially preventing anastomotic leakage.

Putative anoikis-resistant subpopulations in colorectal carcinoma: a marker of adverse prognosis

Anoikis is a form of apoptosis induced when a cell loses contact with the extracellular matrix (ECM). Anoikis resistance is essential for metastasis formation, yet only detectable by in vitro experiments. We present a method for quantitation of putative anoikis-resistant (AR) subpopulations in colorectal carcinoma (CRC) and evaluate their prognostic significance. We studied 137 CRC cases and identified cell subpopulations with and without stromal or extracellular matrix (ECM) contact with hematoxylin-and-eosin-stained sections and immunohistochemistry for laminin and type IV collagen. Suprabasal cells of micropapillary structures and inner cells of cribriform and solid structures lacked both stromal contact and contact with ECM proteins. Apoptosis rate (M30) was lower in these subpopulations than in the other carcinoma cells, consistent with putative AR subpopulation. We determined the areal density of these subpopulations (number/mm² tumor tissue), and their high areal density independently indicates low cancer-specific survival. In conclusion, we show evidence that subpopulations of carcinoma cells in micropapillary, cribriform, and solid structures are resistant to anoikis as shown by lack of ECM contact and low apoptosis rate. Abundance of these subpopulations is a new independent indicator of poor prognosis in CRC, consistent with the importance of anoikis resistance in the formation of metastasis.

Aggressive Inflammatory Myofibroblastic Tumor without Anaplastic Lymphoma Kinase Gene Rearrangement in the Rectum with Liver Metastasis

Inflammatory myofibroblastic tumor is a rare intermediate-grade tumor. We herein report the case of an 81-year-old man with rectal ulceration and abnormal retroperitoneal soft tissue with a high serum level of IgG4. The administration of prednisolone reduced the retroperitoneal lesion; however, the rectal ulceration expanded. Surgical resection was performed. A histopathological examination revealed proliferating spindle cells accompanied by inflammatory cells and plasma cells. Liver metastasis emerged two months after surgical resection, and the histology of the proliferating spindle cells sampled by a fine-needle biopsy was similar to that of the rectal tissue. The patient ultimately died of inflammatory myofibroblastic tumor.

Health costs of post-operative complications following rectal resection: a systematic review

BACKGROUND

Post-operative complications following rectal resection pose significant health and cost implications for patients and health providers. The objective of this study is to review the associated cost of complications following rectal resection. This included reporting on the proportion and severity of these complications, associated length of stay and surgical technique used. Studies were sourced from Embase OVID, MEDLINE OVID (ALL) and Cochrane Library databases by utilizing a search strategy.

METHODS

This search contained studies from 1 January 2010 until 13 February 2019. Studies were included from the year 2010 to account for the implementation of enhanced recovery after surgery protocols. Studies that reported the financial cost associated with complications were included. Any indication for rectal resection was considered. Data was extracted into a formatted table and a narrative synthesis was performed.

RESULTS

We identified 13 eligible studies for inclusion. There was strong evidence to suggest that complications are associated with increased costs. There was considerable variation as to the costs attributable to complications ($1443 (P < 0.001) to $17 831 (P < 0.0012), n = 12). The presence of complications was associated with an increased length of stay (5.54 (P-value not given) to 21.04 (P < 0.0001) days, n = 7). There was significant variation in the proportion of complications (6.41 to 64.71%, n = 8). Weak evidence existed around surgical technique used and the associated cost of complications. There was considerable heterogeneity among included studies.

CONCLUSIONS

Complications following rectal resection increased health costs. Costs should be standardized and provide a clear methodology for their calculation. Complications should be standardized and include a grading of severity.

Spindle cell proliferations of the sigmoid colon, rectum and anus: a review with emphasis on perineurioma

A wide range of spindle cell proliferations are found uncommonly in the sigmoid colon, rectum and anus. They usually present as polyps, and include reactive lesions and benign and malignant neoplasms which may be primary or metastatic. They are less frequently described in the literature compared to those in the upper gastrointestinal tract, and may be underdiagnosed. The widespread use of sigmoidoscopy in symptomatic patients and bowel cancer screening programmes means that histopathologists must be aware of, and adopt a logical approach to, diagnosing spindle cell proliferations in biopsy and polypectomy specimens. This is particularly relevant given the strong association of some mesenchymal polyps with hereditary cancer syndromes. This review article will focus on perineurioma and the recent debate in relation to its overlap with fibroblastic polyp. The clinical, endoscopic, histological and immunohistochemical features of spindle cell proliferations which should be considered in the differential diagnosis of perineurioma will be discussed. There is also a brief reference to malignant spindle cell tumours of diagnostic importance.

Long-term outcomes and prognostic factors of young patients with mucinous and signet-ring cell colorectal cancer

INTRODUCTION

The aim of the study was to assess the clinico-pathological features and prognosis of mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRC) in young colorectal cancer (CRC) patients.

MATERIAL AND METHODS

We retrospectively evaluated the patient records of young patients with MAC and SRC (aged ≤ 40 years) treated at the Cancer Hospital of China Medical University from January 2006 to December 2013. Kaplan-Meier analysis and log-rank testing were performed to estimate overall survival (OS). Subsequently a Cox proportional hazard model was used to calculate hazard ratios for the risk of death.

RESULTS

A total of 90 young CRC patients (MAC = 69 and SRC = 21) were included in the analysis during the study period. The overall cumulative 5-year OS rate was 56.6 ±6%. Estimated 5-year OS was 58.1 ±7.7% for MAC and 31.3 ±12.9% for SRC (p = 0.018). On univariate analysis, metastatic disease, AJCC stage, adjuvant chemotherapy (CT), cycles of adjuvant CT, surgery type, lymphovascular invasion, perineural invasion, preoperative carcinoembryonic antigen (CEA) levels, and histologic type were significant prognostic factors for OS. In multivariate analysis, preoperative CEA levels and cycles of adjuvant CT were found to be independent prognostic factors for overall survival (hazard ratio = 2.47; 95% CI: 1.06-5.78, p = 0.037; hazard ratio = 0.18; 95% CI: 0.05-0.62, p = 0.007, respectively).

CONCLUSIONS

A greater proportion of young patients with MAC and SRC present with advanced disease. Young patients with SRC have poorer prognosis than MAC. Preoperative CEA levels and cycles of adjuvant CT are two independent predictors of overall survival for young CRC patients with MAC and SRC.

Foreign rectal body - Systematic review and meta-analysis

BACKGROUND

Self-inserted foreign rectal bodies are an infrequent occurrence, however they present a serious dilemma to the surgeon, due to the variety of objects, and the difficulty of extraction. The purpose of this study is to give a comprehensive review of the literature regarding the epidemiology, diagnostic tools and therapeutic approaches of foreign rectal body insertion.

METHODS

A comprehensive systematic literature review on Pubmed/ Medline and Google for 'foreign bodies' was performed on January 14th 2018. A meta-analysis was carried out to evaluate the epidemiology, diagnostics and therapeutic techniques. 1,551 abstracts were identified, of which 54 articles were included.

RESULTS

The motivation of foreign rectal body insertion is mostly sexual stimulation. Patients are typically young and predominantly male, with a male to female ratio of 6:1. Sexual devices (35.7%, n=108) and glass objects (17.5%, n=53) are the most commonly self-inserted rectal foreign bodies. Patient history should be taken sensitively after diagnostic evaluation and identification of the object. Removal was performed under general anesthesia in 45.2% (n=95) and sedation in 29.0% (n=61). The total complication rate was described to be 30.4%.

CONCLUSIONS

Diagnostics must be performed with caution in order to rule out perforation and establish a treatment algorithm. Manual transanal extraction under sedation or general anesthesia may be performed in conjunction with cautious abdominal compression. Because of the variety of objects, i.e. in form and material, each case must be treated individually. Sometimes creativity and surgeon imagination may be required, although different algorithms have been established.

Right Ventricle Metastasis from Carcinoma Rectum: Findings on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography

Rectal adenocarcinoma metastasizes most commonly to the lungs and liver. Metastasis to heart, although described in literature, is a very rare phenomenon. We describe the ¹⁸F-fluorodeoxyglucose positron emission tomography–computed tomography (¹⁸F-FDG PET-CT) findings of a 45-year-old male who was a biopsy-proven case of adenocarcinoma rectum. Apart from metastatic disease involving liver, lungs, bone marrow, and lymph nodes, metastasis to right ventricle was also seen on PET-CT scan.

Rectal NETs and rectosigmoid junction NETs may need to be treated differently

Neuroendocrine tumors (NETs) are heterogeneous, and the incidence of NETs is rapidly increasing. We observed different survival in patients with rectal NETs and rectosigmoid junction NETs, which are treated similarly. We included patients with rectal and rectosigmoid junction NETs from the SEER database. The 5‐year survival was set as the end‐point. 6675 patients with rectal NETs and 329 patients with rectosigmoid junction NETs, were eligible for the analysis. Initially, the survival analyses suggested that the 5‐year survival significantly differed between the patients with rectal and rectosigmoid junction NETs (HR = 0.82, 95% CI 0.70‐0.95; P = .01). Tumor differentiation, an invasion deeper than T2, and lymph node and distant metastases were still important risk factors affecting survival for both location. While, the males showed better survival (HR = 0.69, 95% CI 0.55‐0.88; P < .01) and primary tumor surgery had no benefits (P = .56) for patients with rectosigmoid junction NETs. The factors that predict regional lymph node metastases varied by location. In rectal NETs, invasion deeper than T1 and a tumor larger than 1 cm could significantly increase the risk of regional lymph node metastases (all OR > 5, P < .01). In rectosigmoid junction NETs, the risk of regional lymph node metastases was considered significantly higher with invasion deeper than T1 (all OR > 5, P < .01) and a tumor larger than 2 cm (OR = 31.32, 95% CI 2.53‐387.57; P < .01). We advocate a clear and consistent definition of the rectosigmoid junction for future studies, and more studies are needed to determine the reason underlying differences between rectum and rectosigmoid junction.

Colon and rectal cancer risk after bariatric surgery in a multicountry Nordic cohort study

Obesity is a risk factor for colorectal cancer. Yet, some research indicates that weight-reducing bariatric surgery also increases colorectal cancer risk. Our study was undertaken because current evidence examining bariatric surgery and risk of colorectal cancer is limited and inconsistent. This population-based cohort study included adults with a documented obesity diagnosis in Denmark, Finland, Iceland, Norway or Sweden in 1980-2015. The incidence of colorectal cancer in participants with obesity who had and had not undergone bariatric surgery was compared to the incidence in the corresponding background population by calculating standardized incidence ratios (SIR) with 95% confidence intervals (CI). Additionally, operated and nonoperated participants with obesity were compared using multivariable Cox regression, providing hazard ratios (HR) with 95% CIs adjusted for confounders. Among 502,772 cohort participants with an obesity diagnosis, 49,931(9.9%) underwent bariatric surgery. The overall SIR of colon cancer was increased after bariatric surgery (SIR 1.56; 95% CI 1.28-1.88), with higher SIRs ≥10 years postsurgery. The overall HR of colon cancer in operated compared to nonoperated participants was 1.13 (95% CI 0.92-1.39) and 1.55 (95% CI 1.04-2.31) 10-14 years after bariatric surgery. Bariatric surgery did not significantly increase the risk of rectal cancer (SIR 1.14, 95% CI 0.83-1.52; HR 1.08, 95% CI 0.79-1.49), but the risk estimates increased with longer follow-up periods. Our study suggests that bariatric surgery is associated with an increased risk of colon cancer, while the support for an increased risk of rectal cancer was weaker.

Smooth muscle of the male pelvic floor: An anatomic study

Knowledge of the anatomy of the male pelvic floor is important to avoid damaging the pelvic floor muscles during surgery. We set out to explore the structure and innervation of the smooth muscle (SM) of the whole pelvic floor using male fetuses. We removed en-bloc the entire pelvis of three male fetuses. The specimens were serially sectioned before being stained with Masson's trichrome and hematoxylin and eosin, and immunostained for SMs, and somatic, adrenergic, sensory and nitrergic nerve fibers. Slides were digitized for three-dimensional reconstruction. We individualized a middle compartment that contains SM cells. This compartment is in close relation with the levator ani muscle (LAM), rectum, and urethra. We describe a posterior part of the middle compartment posterior to the rectal wall and an anterior part anterior to the rectal wall. The anterior part is split into (1) a centro-levator area of SM cells localized between the right and left LAM, (2) an endo-levator area that upholsters the internal aspect of the LAM, and (3) an infra-levator area below the LAM. All these areas are innervated by autonomic nerves coming from the inferior hypogastric plexus. The core and the infra-levator area receive the cavernous nerve and nerves supplying the urethra. We thus demonstrate that these muscular structures are smooth and under autonomic influence. These findings are relevant for the pelvic surgeon, and especially the urologist, during radical prostatectomy, abdominoperineal resection and intersphincteric resection. Clin. Anat., 2019. © 2019 Wiley Periodicals, Inc.

Management of Malignant Rectal Pain and Tenesmus: A Systematic Review

Background: Malignant rectal pain (MRP) and tenesmus cause significant morbidity for cancer patients at all stages of disease. There is little evidence to guide management of these symptoms. Objective: The objective of this review was to summarize the existing evidence base for palliative management of MRP and tenesmus outside of standard oncologic or surgical management. Design: A systematic review of PubMed and Embase was conducted according to PRISMA guidelines using preselected search terms for publications between 1980 and January 2017. Setting/Subjects: Studies that described management for patients with tenesmoid pain from malignant tumors of the rectum, anus, or perineum were identified. Measurements: The primary outcome was response of pain to treatment. Results: The search produced 1412 titles. Twenty articles met criteria for inclusion in the review, including 11 case series and 9 case reports. A variety of treatments were found with most patients receiving interventional procedures, but overall evidence to support any particular intervention is limited and of poor quality. Conclusions: This review highlights the limited current evidence base for medical and interventional treatments for MRP and tenesmus. Further study is needed to clarify the best approach to managing these challenging symptoms.

Physiological and Pharmaceutical Considerations for Rectal Drug Formulations

Although the oral route is the most convenient route for drug administration, there are a number of circumstances where this is not possible from either a clinical or pharmaceutical perspective. In these cases, the rectal route may represent a practical alternative and can be used to administer drugs for both local and systemic actions. The environment in the rectum is considered relatively constant and stable and has low enzymatic activity in comparison to other sections of the gastrointestinal tract. In addition, drugs can partially bypass the liver following systemic absorption, which reduces the hepatic first-pass effect. Therefore, rectal drug delivery can provide significant local and systemic levels for various drugs, despite the relatively small surface area of the rectal mucosa. Further development and optimization of rectal drug formulations have led to improvements in drug bioavailability, formulation retention, and drug release kinetics. However, despite the pharmaceutical advances in rectal drug delivery, very few of them have translated to the clinical phase. This review will address the physiological and pharmaceutical considerations influencing rectal drug delivery as well as the conventional and novel drug delivery approaches. The translational challenges and development aspects of novel formulations will also be discussed.

Coexistence of Dense and Sparse Areas in the Longitudinal Smooth Muscle of the Anal Canal: Anatomical and Histological Analyses Inspired by Magnetic Resonance Images

Magnetic resonance images of the anal canal show small, circular, low‐intensity areas arranged in a row and a high‐intensity area surrounding them internally and externally in the longitudinal muscle layer that cannot be explained by current anatomical findings. The purpose of this study was to elucidate the detailed structure of the longitudinal smooth muscle of the anal canal and to interpret the magnetic resonance image of the longitudinal muscle. Specimens for macroscopic anatomy and histology were obtained from six and seven cadavers, respectively. The histological nature of the longitudinal muscle was examined by staining serial transverse and coronal sections of the lateral wall of the anal canal with Masson's trichrome stain and using immunohistochemistry for smooth and skeletal muscle fibers. Dense and sparse areas of smooth muscle fibers coexisted in the longitudinal muscle layer. The dense areas formed columnar muscle bundles approximately 1.0–1.5 mm in diameter, and they continued from the longitudinal muscle bundles of the rectum. The columnar muscle bundles of the longitudinal anal muscle were internally and externally surrounded by sparsely arranged smooth muscle fibers that ran longitudinally. The coexistence of dense and sparse areas of smooth muscle fibers suggests that the structure of the smooth muscle is optimized for its function. This histological nature is probably reflected in the magnetic resonance image of the longitudinal muscle as the coexistence of low‐ and high‐intensity areas. Clin. Anat. 33:619–626, 2020. © 2019 Wiley Periodicals, Inc.