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sphincter muscle [keywords]
- Solitary rectal ulcer syndrome in children: a report of six cases. [Journal Article]
- Gut Liver 2013 Nov; 7(6):752-5.
Solitary rectal ulcer syndrome (SRUS) is a rare, benign disorder in children that usually presents with rectal bleeding, constipation, mucous discharge, prolonged straining, tenesmus, lower abdominal pain, and localized pain in the perineal area. The underlying etiology is not well understood, but it is secondary to ischemic changes and trauma in the rectum associated with paradoxical contraction of the pelvic floor and the external anal sphincter muscles; rectal prolapse has also been implicated in the pathogenesis. This syndrome is diagnosed based on clinical symptoms and endoscopic and histological findings, but SRUS often goes unrecognized or is easily confused with other diseases such as inflammatory bowel disease, amoebiasis, malignancy, and other causes of rectal bleeding such as a juvenile polyps. SRUS should be suspected in patients experiencing rectal discharge of blood and mucus in addition to previous disorders of evacuation. We herein report six pediatric cases with SRUS.
- 3D pelvic floor ultrasound findings and severity of anal incontinence. [JOURNAL ARTICLE]
- Int Urogynecol J 2013 Dec 6.
The aim of our study was to determine the association between the severity of anal incontinence and levator ani deficiency, anal sphincter defects, anorectal angle, and colonic motility abnormalities.This was a retrospective study. Subjects were categorized into three groups: normal, minor anal incontinence, and major anal incontinence according to their answers to the PFDI-20 questionnaire. 3D endovaginal ultrasound was utilized to assess levator ani muscle and the anorectal angle. Levator ani muscle subdivisions were scored based on avulsion from the pubic bone and muscle thickness, based on our previous work. 3D endoanal ultrasound was utilized to assess anal sphincters. Colonic motility abnormalities were defined as diarrhea, constipation or both.Ninety-seven patients were included in the analysis: 45 with major anal incontinence, 29 with minor anal incontinence, and 23 continent women. On multivariate logistic regression, sphincter defect, anorectal angle, and colonic motility abnormalities were associated with anal incontinence severity. Women with an external anal sphincter defect had a 20.36-fold chance of having severe anal incontinence compared with patients with no defect (OR 20.36, 95 % CI 5.4, 76.6); those with both defective sphincters had a 102.5-fold chance of having severe anal incontinence (OR 102.5, 95 % CI 10.2, >999). Anorectal angle ≥170° was significantly associated with the severity of anal incontinence (OR = 4.07, 95 % CI 1.53, 10.79), as was the presence of colonic mobility abnormality (OR 5.31, 95 % CI 1.86, 15.19).3D pelvic floor ultrasound can be an efficient tool for anal incontinence evaluation in women. Anal sphincter defects, colonic motility abnormalities, and anorectal angle were associated with the severity of anal incontinence. While there was a trend toward worsening levator ani deficiency among those with major anal incontinence, this did not reach statistical significance.
- Nerve supply to the internal anal sphincter differs from that to the distal rectum: an immunohistochemical study of cadavers. [JOURNAL ARTICLE]
- Int J Colorectal Dis 2013 Dec 5.
Fecal incontinence is a common problem after anal sphincter-preserving operations. The intersphincteric autonomic nerves supplying the internal anal sphincter (IAS) are formed by the union of: (1) nerve fibers from Auerbach's nerve plexus of the most distal part of the rectum and (2) the inferior rectal branches of the pelvic plexus (IRB-PX) running along the conjoint longitudinal muscle coat. The aim of the present study is to identify the detailed morphology of nerves to the IAS.The study comprised histological and immunohistochemical evaluations of paraffin-embedded sections from a large block of anal canal from the preserved 10 cadavers.The IRB-PX came from the superior aspect of the levator ani and ran into the anal canal on the anterolateral side. These nerves contained both sympathetic and parasympathetic fibers, but the sympathetic content was much higher than in nerves from the distal rectum. All intramural ganglion cells in the distal rectum were neuronal nitric oxide synthase-positive and tyrosine hydroxylase-negative and were restricted to above the squamous-columnar epithelial junction. Parasympathetic nerves formed a lattice-like plexus in the circular smooth muscles of the distal rectum, whereas the IAS contained short, longitudinally running sympathetic and parasympathetic nerves, although sympathetic nerves were dominant.The major autonomic nerve input to the IAS seemed not to originate from the distal rectum but from the IRB-PX. Injury to the IRB-PX during surgery seemed to result in loss of innervation to the major part of the IAS.
- Connexin36 in gap junctions forming electrical synapses between motoneurons in sexually dimorphic motor nuclei in spinal cord of rat and mouse. [JOURNAL ARTICLE]
- Eur J Neurosci 2013 Dec 5.
Pools of motoneurons in the lumbar spinal cord innervate the sexually dimorphic perineal musculature, and are themselves sexually dimorphic, showing differences in number and size between male and female rodents. In two of these pools, the dorsomedial nucleus (DMN) and the dorsolateral nucleus (DLN), dimorphic motoneurons are intermixed with non-dimorphic neurons innervating anal and external urethral sphincter muscles. As motoneurons in these nuclei are reportedly linked by gap junctions, we examined immunofluorescence labeling for the gap junction-forming protein connexin36 (Cx36) in male and female mice and rats. Fluorescent Cx36-labeled puncta occurred in distinctly greater amounts in the DMN and DLN of male rodents than in other spinal cord regions. These puncta were localized to motoneuron somata, proximal dendrites, and neuronal appositions, and were distributed either as isolated or large patches of puncta. In both rats and mice, Cx36-labeled puncta were associated with nearly all (> 94%) DMN and DLN motoneurons. The density of Cx36-labeled puncta increased dramatically from postnatal days 9 to 15, unlike the developmental decreases in these puncta observed in other central nervous system regions. In females, Cx36 labeling of puncta in the DLN was similar to that in males, but was sparse in the DMN. In enhanced green fluorescent protein (EGFP)-Cx36 transgenic mice, motoneurons in the DMN and DLN were intensely labeled for the EGFP reporter in males, but less so in females. The results indicate the presence of Cx36-containing gap junctions in the sexually dimorphic DMN and DLN of both male and female rodents, suggesting coupling of not only sexually dimorphic but also non-dimorphic motoneurons in these nuclei.
- Gender-related Fetal Development of the Internal Urethral Sphincter. [Journal Article]
- Urology 2013 Dec; 82(6):1410-5.
To investigate the fetal development of the internal urethral sphincter and the gender-related morphologic differences of the bladder outlet.Thirty-seven (14 female, 23 male) fetal bladder neck specimens (mean gestational age, 19.4 weeks) with the smooth muscle complex of the internal sphincter were investigated histologically. After immunostaining serial sections in 3 reference planes (sagittal, frontal, and horizontal) of the bladder neck, the internal sphincter volumes and bladder outlet diameters were measured and correlated with gender and age of gestation.Between the 18th and 40th week of gestation, an exponential growth of the internal sphincter muscle with significant higher volumes could be observed in male fetuses compared with female fetuses (internal sphincter volumes, P = .006; radius of the sphincter complex, P = .001). As a result of this gender difference, the bladder outlet was significantly (P = .001) narrower in male than in female fetuses. Moreover, we found a significant positive correlation between age and all measured parameters in both male and female specimens.The present study indicates a significant closer bladder outlet in male fetuses compared than in females. It thereby provides evidence of a gender-related functional obstruction in addition to a suppositious transient infravesical obstruction in male human fetuses.
- Distensibility of the anal canal in patients with idiopathic fecal incontinence: a study with the Functional Lumen Imaging Probe. [JOURNAL ARTICLE]
- Neurogastroenterol Motil 2013 Nov 29.
Anatomical structures and their distensibility vary along the length of the anal canal. The anal sphincter muscles have dynamic properties that are not well-reflected by standard manometry. Abnormal distensibility of the anal canal may be of importance in idiopathic fecal incontinence (IFI). The functional lumen imaging probe (FLIP) allows detailed studies of the distensibility and axial variation of sphincters. We aimed at comparing segmental distensibility of the anal canal in patients with IFI and healthy subjects.The FLIP was used for distension of the anal canal in 22 patients with IFI (17 female, age 27-82 years) and 21 healthy volunteers (18 female, age 32-73 years). The distensibility was determined from changes in luminal diameter. Closure of the anal canal during voluntary squeeze was computed as the combined length of closed anal canal and time. Pressure-strain elastic modulus was computed at rest.In all subjects, the proximal anal canal was the most distensible segment. During distension at rest and during squeeze the middle and distal anal canal became significantly larger in IFI than in healthy (F < 22.4, p < 0.05). The closure of the anal canal during voluntary squeeze did not differ between healthy (75.9 ± 92.9 mm s) and IFI patients (90.4 ± 105 mm s; p = 0.6). Compared with healthy, IFI patients had lower pressure-strain elastic modulus of the middle and distal (q > 4.5, p < 0.05) but not the proximal anal canal (q < 0.7, p > 0.05).Patients with IFI have increased distensibility of the middle and distal parts of the anal canal.
- Safe ablation of the anal mucosa and perianal skin in rats using Photodynamic Therapy-A promising approach for treating Anal Intraepithelial Neoplasia. [Journal Article]
- Photodiagnosis Photodyn Ther 2013 Dec; 10(4):566-74.
Anal Intraepithelial Neoplasia (AIN), a pre-cursor of anal squamous carcinoma, is increasingly detected in individuals with impaired immune function. However, choices for effective, low morbidity treatment are limited. Photodynamic Therapy (PDT) is promising as it is known to ablate more proximal gastrointestinal mucosa with safe healing, without damage to underlying muscle. It can also ablate skin with safe healing and minimal scarring.Pharmacokinetics: Normal rats were sensitised with 200mg/kg 5-aminolaevulinic acid (ALA) and killed 1-8h later. Anal tissues were examined by fluorescence microscopy to quantify the concentration of PPIX (protoporphyrin IX, the active derivative of ALA) in anal mucosa and in the underlying sphincter. PDT: Normal rats were sensitised similarly 3h later, laser light (635nm) was delivered. Anal canal: 50-150J/cm using 1cm diffuser fibre; for peri-anal skin, 50-200J/cm(2), using microlens fibre. In each group, 2 rats were killed 3, 7, 14 and 28days later and the anal region removed for histological examination.Pharmacokinetics: Peak concentration of PPIX in mucosa was at 3h, peak ratio mucosa: muscle, 6, seen at same time. PDT. Anal canal 50J/cm: complete mucosal ablation by 3 days, complete regeneration by 28 days. Higher energies caused muscle damage with scarring. Peri-anal skin: 200J/cm(2); complete ablation of skin, including appendages, complete healing by 28 days. Minimal effect with lower energy.ALA-PDT can ablate anal mucosa and peri-anal skin with safe healing and no underlying damage. However, over treatment can damage the sphincters. This technique is ready to undergo clinical trials.
- Surgical management of fecal incontinence. [Journal Article]
- Gastroenterol Clin North Am 2013 Dec; 42(4):815-36.
The surgical approach to treating fecal incontinence is complex. After optimal medical management has failed, surgery remains the best option for restoring function. Patient factors, such as prior surgery, anatomic derangements, and degree of incontinence, help inform the astute surgeon regarding the most appropriate option. Many varied approaches to surgical management are available, ranging from more conservative approaches, such as anal canal bulking agents and neuromodulation, to more aggressive approaches, including sphincter repair, anal cerclage techniques, and muscle transposition. Efficacy and morbidity of these approaches also range widely, and this article presents the data and operative considerations for these approaches.
- Recombinant insulin-like growth factor-1 activates satellite cells in the mouse urethral rhabdosphincter. [JOURNAL ARTICLE]
- BMC Urol 2013 Nov 26; 13(1):62.
The goal of this study is to demonstrate the efficacy of a new method for the treatment of urinary incontinence by stimulation of urethral rhabdosphincter satellite cells. We show that satellite cells do exist in the sphincter muscle of retired male mice breeders by staining for c-Met, a satellite cell specific protein. Once activated by recombinant mouse Insulin-like Growth Factor-1(rIgf-1), the satellite cells develop into muscle cells within the rhabdosphincter thereby potentially strengthening it.20 mul (1 mug/mul) of rIgf-1 was surgically injected directly into the urethral wall of retired male mouse breeders. Mice injected with phosphate buffered saline (PBS) were used as controls. 4 weeks later, urethras were harvested and serially-sectioned through the sphincter for routine hematoxylin-eosin staining as well as immunohistochemical staining with satellite cell specific anti-c-Met antibody and proliferation specific anti-Ki-67 antibody.Anti-c-Met antibody positive cells (c-Met+) were identified in the rhabdosphincter. c-Met+ cells increased by 161.8% relative to controls four weeks after rIGF-1 injection. Anti- Ki-67 antibody positive cells were identified and characterized as cells with centrally located nuclei in striated muscle bundles of rIGF-1 treated animals.Satellite cells in the mouse rhabdosphincter can be activated by rIGF-1 treatment, which subsequently are incorporated into existing skeletal muscle bundles. Using this approach, the rhabdosphincter can be induced to regenerate and potentially strengthen via satellite cell activation and likely improve urinary continence.
- Correlation of Histopathology With Anorectal Manometry Following Stapled Hemorrhoidopexy. [JOURNAL ARTICLE]
- Ann Coloproctol 2013 Oct; 29(5):198-204.
The removal of smooth muscle during stapled hemorrhoidopexy raises concerns regarding its effects on postoperative anorectal function. The purpose of this study was to evaluate the correlation between the amount of muscle removed and changes in anorectal manometry following stapled hemorrhoidopexy.Patients with symptomatic II, III, or IV degree hemorrhoids that underwent stapled hemorrhoidopexy between January 2008 and May 2011 were included in this study. Anorectal manometry was performed preoperatively and at three months postoperatively. The resected doughnuts were examined histologically, and the thicknesses of muscle fibers were evaluated.Eighty-five patients (34 males) with a median age of 47 years were included. Muscularis propria fibers were identified in 63 of 85 pathologic specimens (74.1%). The median thickness of the muscle fibers was 1.58 ± 1.21 mm (0 to 4.5 mm). The mean resting pressure decreased by approximately 7 mmHg after operation in the 85 patients (P = 0.019). In patients with muscle incorporation, there was a significant difference in mean resting pressure (P = 0.041). In the analysis of the correlation of the difference in anorectal manometry results ([the result of postsurgical anorectal manometry] - [the result of presurgical anorectal manometry]) to the thickness of muscle fibers, no significant differences were seen. No patients presented with fecal incontinence.Although the incidence of fecal incontinence is very low, muscle incorporation in the resected doughnuts following stapled hemorrhoidopexy may affect anorectal pressure. Therefore, surgeons should endeavor to minimize internal sphincter injury during stapled hemorrhoidopexy.