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sphincter muscle [keywords]
- Current aspects and future prospects of total anorectal reconstruction-a critical and comprehensive review of the literature. [JOURNAL ARTICLE]
- Int J Colorectal Dis 2014 Nov 19.
Many rectal cancer patients undergo abdominoperineal excision worldwide every year. Various procedures to restore perineal (pseudo-) continence, referred to as total anorectal reconstruction, have been proposed. The best technique, however, has not yet been defined. In this study, the different reconstruction techniques with regard to morbidity, functional outcome and quality of life were analysed. Technical and timing issues (i.e. whether the definitive procedure should be performed synchronously or be delayed), oncological safety, economical aspects as well as possible future improvements are further discussed.A MEDLINE and EMBASE search was conducted to identify the pertinent multilingual literature between 1989 and 2013. All publications meeting the defined inclusion/exclusion criteria were eligible for analysis.Dynamic graciloplasty, artificial bowel sphincter, circular smooth muscle cuff or gluteoplasty result in median resting and squeezing neo-anal pressures that equate to the measurements found in incontinent patients. However, quality of life was generally stated to be good by patients who had undergone the procedures, despite imperfect continence, faecal evacuation problems and a considerable associated morbidity. Many patients developed an alternative perception for the urge to defecate that decisively improved functional outcome. Theoretical calculations suggested cost-effectiveness of total anorectal reconstruction compared well to life with a permanent colostomy.Many patients would be highly motivated to have their abdominal replaced by a functional perineal colostomy. Given the considerable morbidity and questionable functional outcome of current reconstruction technique improvements are required. Tissue engineering might be an option to design an anatomically and physiologically matured, and customised continence organ.
- Complications and urologic risks of neurogenic bladder in veterans with traumatic spinal cord injury. [JOURNAL ARTICLE]
- Spinal Cord 2014 Nov 18.
Objectives:This observational study aimed to determine the types of urological lesion encountered in veterans with traumatic spinal cord injury (SCI) with neurogenic bladder (NGB), and the usage of bladder management programs to deal with NGB.Setting:NGB (detrusor muscle and urethral sphincter dysfunction with loss of bladder sensation to void) is common in daily practice; however, information on types of urological lesions encountered in these veterans with NGB and how best to manage their NGB is limited.Methods:We retrospectively reviewed the electronic charts of veterans with SCI enrolled in our program and regularly followed in our SCI clinic. Demographic data collected included: age, gender, ethnicity and age, level, severity and cause of spinal injury. Also noted was presence of NGB, episodes of urinary tract infection (UTI), bladder program followed and urological lesions found on renal nuclear scans, renal ultrasounds and cystoscopies.Results:Of the 161 veterans with SCI, symptoms of NGB was present in 133 (82.6%). Veterans with NGB had more severe spinal injury and more frequent UTI (P<0.05). Renal atrophy and hydronephrosis were the most common urological lesions seen in patients with UTI. Clean intermittent catheterization (CIC) was the most frequently used bladder program resulting in less frequent occurrence of UTI.Conclusion:Renal atrophy and hydronephrosis were the most common urological lesions encountered in veterans with NGB especially in those with UTI. CIC was the most frequently used bladder management program with the least risk for UTI.Spinal Cord advance online publication, 18 November 2014; doi:10.1038/sc.2014.205.
- Dominant role of interstitial cells of Cajal in nitrergic relaxation of murine lower esophageal sphincter. [JOURNAL ARTICLE]
- J Physiol 2014 Nov 10.
Esophageal achalasia is a disease known to result from reduced relaxation of the lower esophageal sphincter. Nitric oxide (NO) is one of the main inhibitory transmitters. NO-sensitive guanylyl cyclase (NO-GC) acts as the key target of NO and, by the generation of cGMP, mediates nitrergic relaxation in the lower esophageal sphincter (LES). To date, the exact mechanism of nitrergic LES relaxation is still insufficiently elucidated. To clarify the role of NO-GC in LES relaxation, we used cell-specific knockout mouse lines for NO-GC. These include mice lacking NO-GC in smooth muscle cells (SMC-GCKO), in interstitial cells of Cajal (ICC-GCKO) and in both SMC/ICC (SMC/ICC-GCKO). We applied esophageal manometry to study the functionality of LES in vivo. Isometric force studies were performed to monitor LES responsiveness to exogenous NO and electric field stimulation of intrinsic nerves in vitro. Cell-specific expression/deletion of NO-GC was monitored by immunohistochemistry. Swallowing-induced LES relaxation is strongly reduced by deletion of NO-GC in ICC. Basal LES tone is affected by NO-GC deletion in either SMC or ICC. Lack of NO-GC in both cells leads to a complete interruption of NO-induced relaxation and, therefore, to an achalasia-like phenotype similar to that seen in global GCKO mice. Our data indicate that regulation of basal LES tone is based on a dual mechanism mediated by NO-GC in SMC and ICC whereas swallow-induced LES relaxation is mainly regulated by nitrergic mechanisms in ICC. This article is protected by copyright. All rights reserved.
- Predicting Birth-Related Levator Ani Tear Severity in Primiparous Women: Evaluating Maternal Recovery from Labor and Delivery (EMRLD Study). [JOURNAL ARTICLE]
- Open J Obstet Gynecol 2014 Apr 1; 4(6):266-278.
To determine which maternal characteristics or birth events independently predict severity of levator ani muscle (LA) tears at first vaginal birth in a longitudinal/observational investigation in a tertiary care hospital.Ninety primiparas with at least one at risk for LA tear inclusion factor at vaginal birth: maternal age ≥ 33 years, second stage ≥ 150 minutes, macrosomia, instrumented delivery, and/or anal sphincter laceration were studied.Magnetic Resonance Imaging (MRI) was obtained early postpartum (mean ± sd 48.9 ± 21.6 days) to identify LA tear. Severity of LA muscle fiber loss was graded on an ordinal scale of: "0" as no loss, "1" as <50% unilateral loss, "2" as ≥50% unilateral or <50% bilateral loss, and "3" as ≥50% bilateral loss. Data were analyzed using proportional odds modeling. Inclusion factors were explored as predictors of LA tear severity and at analysis episiotomy, time spent actively pushing, epidural, and oxytocin were also considered. The main outcome measures of interest included grading of severity of LA muscle fiber loss on an ordinal scale.Respective counts/percentages of women within each 0 thru 3 ordered category of LA tear severity were: "0" = 58(64%), "1" = 9(10%), "2" = 15(17%), and "3" = 8(9%). Estimates and 95% CI for significant demographic or obstetric univariate predictors of LA tear severity level were age, OR 1.093 (CI 1.012 - 1.180), p = 0.023; and time spent in active pushing, OR 1.089 (CI 1.005 - 1.180), p = 0.038. The other factors considered were not significant. There were too few women with forceps deliveries to analyze. CONCLUSION: In our enriched sample of primiparous women, 26% showed a significant LA tear. Maternal age and time spent actively pushing independently predict LA tear severity.
- MESENCHYMAL STEM CELLS AND THEIR SECRETOME PRESERVE NERVE AND URETHRAL FUNCTION IN A DUAL MUSCLE AND NERVE INJURY STRESS URINARY INCONTINENCE MODEL. [JOURNAL ARTICLE]
- Am J Physiol Renal Physiol 2014 Nov 5.:ajprenal.00510.2014.
Childbirth injures muscles and nerves responsible for urinary continence. Mesenchymal stem cells (MSCs) or their secretome given systemically could provide therapeutic benefit for this complex multisite injury. We investigated if MSCs or their secretome, as collected from cell culture, facilitate recovery from simulated childbirth injury. Age-matched female Sprague Dawley rats received pudendal nerve crush and vaginal distension (PNC+VD) and a single intravenous (iv) injection of 2 million MSCs or saline. Controls received sham injury and iv saline. Additional rats received PNC+VD and a single intraperitoneal (ip) injection of concentrated media conditioned by MSCs (CCM) or concentrated control media (CM). Controls received a sham injury and ip CM. Urethral and nerve function were assessed with leak point pressure (LPP) and pudendal nerve sensory branch potential (PNSBP) recordings 3 wk after injury. Urethral and pudendal nerve anatomy were assessed qualitatively by blinded investigators. Quantitative data was analyzed using one-way ANOVA and Holm-Sidak posthoc tests with p<0.05 indicating significant differences. Both LPP and PNSBP were significantly decreased 3 wk after PNC+VD with saline or CM compared to sham injured rats, but not with MSC or CCM. Elastic fiber density in the urethra increased and changed in orientation after PNC+VD with a greater increase in elastic fibers with MSC or CCM. Pudendal nerve fascicles were less dense and irregularly shaped after PNC+VD, and had reduced pathology with MSC or CCM. MSC and CCM provide similar protective effects after PNC+VD, suggesting that MSCs act via their secretions in this dual muscle and nerve injury. -
- Infantile hypertrophic pyloric stenosis (IHPS): A study of its pathophysiology utilizing the newborn hph-1 mouse model of the disease. [JOURNAL ARTICLE]
- Am J Physiol Gastrointest Liver Physiol 2014 Oct 30.:ajpgi.00221.2014.
Infantile hypertrophic pyloric stenosis (IHPS) is a common disease of unknown etiology. The tetrahydrobiopterin (BH4) - deficient hph-1 newborn mouse has a similar phenotype to the human condition. hph-1 and wild-type control animals' pyloric tissue agonist-induced contractile properties, reactive oxygen species (ROS) generation, cGMP, neuronal nitric oxide synthase (nNOS) content, as well as, ROCK-2 expression and activity were evaluated. Primary pyloric smooth muscle cells from wild-type newborn animals were utilized to evaluate the effect of tetrahydrobiopterin (BH4) deficiency. One-week old hph-1 mice exhibited a 4-fold increase (P<0.01) in the pyloric sphincter muscle contraction magnitude, but similar relaxation values, when compared with wild-type animals. The pyloric tissue nNOS expression and cGMP content were decreased, while the rate of nNOS uncoupling increased (p<0.01) in one-week old hph-1 mice, when compared with wild-type animals. These changes were associated with increased pyloric tissue ROS generation and elevated ROCK-2 expression/activity (p<0.05). At 1-3 days of age and during adulthood, the hph-1 mice's gastric emptying rate was not altered and there were no genotype differences in pyloric tissue ROS generation, nNOS expression or ROCK-2 activity. BH4 inhibition in pyloric smooth muscle cells, resulted in increased ROS generation (p<0.01) and ROCK-2 activity (p<0.05). Oxidative stress upregulated ROCK-2 activity in pyloric, but no changes were observed in newborn fundal tissue in vitro. We conclude that ROS-induced upregulation of ROCK-2 expression accounts for the increased pyloric sphincter tone and nNOS downregulation in the newborn hph-1 mice. The role of ROCK-2 activation in the pathogenesis of IHPS warrants further study.
- Identification of motor neurons and a mechanosensitive sensory neuron in the defecation circuitry of Drosophila larvae. [JOURNAL ARTICLE]
- Elife 2014 Oct 30.
Defecation allows the body to eliminate waste, an essential step in food processing for animal survival.In contrast to the extensive studies of feeding, its obligate counterpart, defecation, has received much less attention until recently. Here we report our characterizations of the defecation behavior of Drosophila larvae and its neural basis. Drosophila larvae display defecation cycles of stereotypic frequency, involving sequential contraction of hindgut and anal sphincter. The defecation behavior requires two groups of motor neurons that innervate hindgut and anal sphincter, respectively, and can excite gut muscles directly. These two groups of motor neurons fire sequentially with the same periodicity as the defecation behavior, as revealed by in vivo Ca(2+) imaging. Moreover, we identified a single mechanosensitive sensory neuron that innervates the anal slit and senses the opening of the intestine terminus. This anus sensory neuron relies on the TRP channel NOMPC but not INACTIVE, NANCHUNG, or PIEZO for mechanotransduction.
- Retraction of the Soft Palate During a Modified Hynes Pharyngoplasty: A Technical Note. [JOURNAL ARTICLE]
- Cleft Palate Craniofac J 2014 Oct 28.
Surgical management of velopharyngeal insufficiency by construction of sphincter pharyngoplasty is well described in the medical literature. Hynes advocated splitting an intact soft palate when it would be helpful for better exposure of the posterior pharyngeal wall for flap inset. We describe a modification used in modified Hynes pharyngoplasty whereby the soft palate is retracted upward, giving the operator unrestricted surgical access to the salpingopharyngeus muscles and their overlying mucosa. This allows the surgeon to raise and inset the flaps, as described by Hynes, without the need to divide the soft palate. The retraction catheters avoid the need for splitting a soft palate, whose function has been optimized by either a Furlow or soft palate re-repair in the past, avoiding unnecessary compromise of the integrity and architecture of the soft palate.
- Anal sphincter complex: 2D and 3D endoanal and translabial ultrasound measurement variation in normal postpartum measurements. [JOURNAL ARTICLE]
- Int Urogynecol J 2014 Oct 25.
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.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).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.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.
- Topography of the extrinsic internal anal sphincter nerve supply during laparoscopic-assisted TAMIS TME: five key zones of risk from the surgeons' view. [JOURNAL ARTICLE]
- Int J Colorectal Dis 2014 Oct 15.
Sparing the extrinsic autonomic innervation of the internal anal sphincter during total mesorectal excision is important for the preservation of anal sphincter function. This study electrophysiologically confirmed the topography of the internal anal sphincter nerve supply during laparoscopic-assisted transanal minimally invasive surgery for total mesorectal excision.This prospective study was conducted at two large multispecialty referral centers. Six patients (five males and one female) aged between 45 and 65 years with low rectal cancer (≤5 cm from the anal verge) were enrolled. Surgery was performed under electric stimulation of the pelvic autonomic nerves with observation of the electromyographic signals of the internal anal sphincter.The minimally invasive transanal surgical approach enabled advantageous visualization of the pelvic autonomic nerves in all patients. In particular, extrinsic innervation to the internal anal sphincter near the levator muscle was consciously spared under electrophysiological confirmation. The evoked absolute electromyographic amplitudes of the internal anal sphincter during transanal minimally invasive surgery were significantly lower than the initial results of the laparoscopic approach [3.7 μV (interquartile range 2.4; 5.7) vs. 4.3 μV (interquartile range 3.1; 8.6); p = 0.002]. Five key zones of risk for pelvic autonomic nerve damage were identified. No complications occurred.The electromyographic results of this preliminary study indicate advantages for sparing the internal anal sphincter innervation during transanal minimally invasive mesorectal dissection considering the specific in situ neuroanatomical topography.