Role of three-dimensional endoanal ultrasound in assessing the anal sphincter morphology of female patients with chronic proctalgia

AIM To assess the role of three-dimensional endoanal ultrasound (3D-EAUS) for morphological assessment of the anal sphincter of female patients with chronic proctalgia (CP). METHODS In this unmatched case control study, 30 consecutive female patients with CP and 25 normal women (control group) were enrolled. 3D-EAUS was performed in all subjects. Thickness and length of internal anal sphincter (IAS), thickness of puborectalis muscle (PR), length of the external anal sphincter (EAS) plus PR, and puborectalis angle were measured and compared between the two groups. RESULTS Patients with CP had significantly shorter IAS length and greater PR thickness, as compared to those in normal individuals (26.28 +/- 3.59 mm vs 28.87 +/- 4.84 mm, P < 0.05 and 9.67 +/- 1.57 mm vs 8.85 +/- 0.97 mm, P < 0.05, respectively). No significant between-group differences were observed with respect to IAS thickness and the EAS plus PR length (P > 0.05). Puborectalis angle in the CP group was significantly decreased, both in resting (88.23 degrees +/- 1.81 degrees vs 89.94 degrees +/- 2.07 degrees in control group, P < 0.05) and straining (88.47 degrees +/- 3.32 degrees vs 90.72 degrees +/- 1.87 degrees in control group, P < 0.05) phases, which suggest the presence of paradoxical contraction of PR in patients with CP. In the CP group, no significant difference in puborectalis angle was observed between the resting and straining phases (88.23 degrees +/- 1.81 degrees vs 88.47 degrees +/- 3.32 degrees respectively, P > 0.05). CONCLUSION The association of greater PR thickness and paradoxical contraction of PR with CP suggest their potential value as markers of CP.

Including video and novel parameter-height of penetration of external anal sphincter-in magnetic resonance imaging reporting of anal fistula

The main purpose of a radiologist’s expertise in evaluation of anal fistula magnetic resonance imaging(MRI)is to benefit patients by decreasing the incontinence rate and increasing the healing rate.Any loss of vital information during the transfer of this data from the radiologist to the operating surgeon is unwarranted and is best prevented.In this regard,two methods are suggested.First,a short video to be attached with the standardized written report highlighting the vital parameters of the fistula.This would ensure minimum loss of information when it is conveyed from the radiologist to the operating surgeon.Second,inclusion of a new parameter,the amount of external sphincter involvement by the anal fistula.This parameter is usually not included in the MRI report.This can be evaluated as the height of penetration of the external anal sphincter(HOPE)by the fistula.The external anal sphincter plays a pivotal role in maintaining continence.This parameter(HOPE)is distinct from the‘height of internal opening’and assumes immense importance as its knowledge is paramount to prevent damage to the external anal sphincter by the surgeon during surgery.

Lack of nitrate tolerance in isosorbid dinitrate- and sodium nitroprusside-induced relaxation of rabbit internal anal sphincter

AIM: To investigate the tolerance development against the relaxant effect of nitric oxide donating drug isosorbide dinitrate (ISDN) and sodium nitropruside (SNP) in internal anal sphincter (IAS) smooth muscle. METHODS: Relaxation responses of ISDN, and electrical fi eld stimulation (EFS) were obtained before and after tolerance induction by ISDN incubation. RESULTS: ISDN (10-7-10-4 mol/L) and SNP (10-8-10-4 mol/L) caused a concentration-dependent relaxation on the basal tonus of the isolated rabbit IAS strips. After a period of 2 h incubation of the 6 x 10-4 mol/L ISDN the relaxation effects of ISDN and SNP did not change compared to control strips. EFS evoked frequency-dependent relaxation in internal anal sphincter smooth muscle and Emax obtained from control strips were not changed in ISDN tolerance-inducing condition. In this study nitrate tolerance was not observed in rabbit IAS smooth muscle. CONCLUSION: This result shows that nitric oxide donating drugs relaxes the internal anal sphincter of the rabbits without the development of tolerance.

Anal Sphincter Function after Intersphincteric Resection for Low Rectal Cancer

Objective： To assess the anal sphincter function after intersphincteric resection for low rectal cancer by questionnaire and vectorial manometry. Methods： twenty five patients underwent intersphincteric resection, the controls contained 25 patients of rectal cancer who underwent low anterior resection and 25 healthy people. The therapeutic responses were evaluated using the Vaizey and Wexner scoring systems and vectorial manometry. Results： The Vaizey and Wexner scores after intersphincteric resection were significantly higher than those of low anterior resection controls at one month, but had no significant difference one year after. On the other hand, the indexes of vectorial manometry still had significant difference one year later. The indexes after intersphincteric resection could not reach the normal level. Conclusion： The anal sphincter function after intersphincteric resection is lower than that after low anterior resection in short term, although the long-term results can be accepted, it still can not reach the normal level.

A novel artificial anal sphincter system based on transcutaneous energy transmission

For controlling anal incontinence,a new artificial anal sphincter system (AASS) with sensor feed-back based on transcutaneous energy transmission is developed.The device mainly comprises an artificialanal sphincter (AAS),a wireless power supply subsystem,and a communication subsystem.The artifi-cial anal sphincter comprises a front cuff and a sensor cuff placed around the rectum,a reservoir sited inabdominal cavity and a micropump controlling inflation and deflation of the front cuff.There are two pres-sure sensors in the artificial anal sphincter.One can measure the pressure in the front cuff to clamp therectum,the other in the sensor cuff can measure the pressure of the rectum.Wireless power supply sub-system includes a resonance transmit coil to transmit an alternating magnetic field and a secondary coil toreceive the power.Wireless communication subsystem can transmit the pressure information of the artifi-cial anal sphincter to the monitor,or send the control commands to the artificial anal sphincter.A proto-type is designed and the basic function of the artificial anal sphincter system has been tested through ex-periments.The results demonstrate that the artificial anal sphincter system can control anal incontinenceeffectively.

Rat model of anal sphincter injury and two approaches for stem cell administration

AIM To establish a rat model of anal sphincter injury and test different systems to provide stem cells to injured area.METHODS Adipose-derived stem cells(ASCs) were isolated from BDIX rats and were transfected with green fluorescent protein(GFP) for cell tracking. Biosutures(sutures covered with ASCs) were prepared with 1.5 × 10~6 GFPASCs, and solutions of 10~6 GFP-ASCs in normal saline were prepared for injection. Anorectal normal anatomy was studied on Wistar and BDIX female rats. Then, we designed an anal sphincter injury model consisting of a 1-cm extra-mucosal miotomy beginning at the anal verge in the anterior middle line. The sphincter lesion was confirmed with conventional histology(hematoxylin and eosin) and immunofluorescence with 4', 6-diamidino-2-phenylindole(commonly known as DAPI), GFP and α-actin. Functional effect was assessed with basal anal manometry, prior to and after injury. After sphincter damage, 36 BDIX rats were randomized to three groups for:(1) Cell injection without repair;(2) biosuture repair; and(3) conventional suture repair and cell injection. Functional and safety studies were conducted on all the animals. Rats were sacrificed after 1, 4 or 7 d. Then, histological and immunofluorescence studies were performed on the surgical area.RESULTS With the described protocol, biosutures had been covered with at least 820000-860000 ASCs, with 100% viability. Our studies demonstrated that some ASCs remained adhered after suture passage through the muscle. Morphological assessment showed that the rat anal anatomy is comparable with human anatomy; two sphincters are present, but the external sphincter is poorly developed. Anal sphincter pressure data showed spontaneous, consistent, rhythmic anal contractions, taking the form of "plateaus" with multiple twitches(peaks) in each pressure wave. These basal contractions were very heterogeneous; their frequency was 0.91-4.17 per min(mean 1.6980, SD 0.57698), their mean duration was 26.67 s and mean number of peaks was 12.53. Our morphological assessment revealed that with the aforementioned surgical procedure, both sphincters were completely sectioned. In manometry, the described activity disappeared and was replaced by a gentle oscillation of basal line, without a recognizable pattern. Surprisingly, these findings appeared irrespective of injury repair or not. ASCs survived in this potentially septic area for 7 d, at least. We were able to identify them in 84% of animals, mainly in the muscular section area or in the tissue between the muscular endings. ASCs formed a kind of "conglomerate" in rats treated with injections, while in the biosuture group, they wrapped the suture. ASCs were also able to migrate to the damaged zone. No relevant adverse events or mortality could be related to the stem cells in our study. We also did not find unexpected tissue growths. CONCLUSION The proposed procedure produces a consistent sphincter lesion. Biosutures and injections are suitable for cell delivery. ASCs survive and are completely safe in this clinical setting.

Modeling of human colonic blood flow for a novel artificial anal sphincter system

A novel artificial anal sphincter system has been developed to simulate the normal physiology of the human anorectum. With the goal of engineering a safe and reliable device, the model of human colonic blood flow has been built and the relationship between the colonic blood flow rate and the operating occlusion pressure of the anorectum is achieved. The tissue ischemia is analyzed based on constitutive relations for human anorectum. The results suggest that at the planned operating occlusion pressure of less than 4 kPa the artificial anal sphincter should not risk the vascularity of the human colon.

Change in Deferring Time Correlate to Improved Female Sexual Function after Anal Sphincter Repair: A Prospective Study

Background: Many women suffer from sexual problems after anal sphincter tears due to obstetric trauma. Aim: The study aimed to assess changes in sexual function after anal sphincter repair. Methods: The study was a non-randomized prospective observational cohort study. Inclusion of the study was done at the University Hospital, Uppsala, Sweden, between 2002 and 2007. Thirty-nine consecutive female patients admitted for anal sphincter repair were invited to the study. Twenty patients accepted and were included, four were lost to follow up and one was unevaluable (due to the formation of a stoma) leaving a study group of 15 patients. The patients were assessed with questionnaires before surgery and at three and 12 months after surgery. Outcomes: Change in reported sexual activity and dyspareunia. Results: Before surgery, 12/15 patients reported that their sexual life was impaired due to anal incontinence. The corresponding figure at 12 months was 9/15 (p = 0.43). Three patients remained sexually inactive throughout the study, five patients increased their sexual activity and one had decreased activity. Out of the 12 who were active, four stated dyspareunia at baseline, and only one reported dyspareunia at 12 months. The mean Miller incontinence scores at baseline and 12 months were 10.1 and 8.7, respectively. The change in incontinence score did not differ between those with decreased, stable or increased sexual activity. However, there was a definite correlation (r = 0.54 - 0.60, p 0.05) between change in sexual function and deferring time for stool. Clinical Implications: Operative management of anal sphincter tears alone is not curative for sexual problems due to anal incontinence but can be a part of the treatment. Strengths and Limitations: The study is a prospective study of sexual function. The limitations are that the questionnaires were not validated due to lack of such questionnaires at the time of the study and that the study population is quite small. Conclusion: Patients with a sphincter injury and fecal incontinence often have an impaired sexual function. Increased deferring time for stools after surgery increases the likelihood of improved sexual function.

Risk factors for internal anal sphincter dysfunction in Japanese adults

Purpose: The internal anal sphincter provides most of the resting anal tone and is the main muscle responseble for continence. This study was designed to estimate the prevalence of, and identify risk factors associated with, internal anal sphincter dysfunction in Japanese adults. Methods: Anorectal manometry was performed in 1193 women and 1124 men aged 20 years or older. The maximal resting pressure, measured by a rapid pull-through technique, was defined as the highest resting pressure recorded. Internal anal sphincter dysfunction was defined as a maximal resting pressure less than 30 mmHg. Potential risk factors were assessed through self-reports, interviews, physical examinations, and medical record reviews. Multivariate logistic regression analysis was used to identify independent risk factors for internal anal sphincter dysfunction. Results: Significant differences in maximal resting pressure were seen between women (58.1 ± 24.9 mmHg) and men (68.8 ± 23.5 mmHg, P < 0.001). Maximal resting pressure decreased significantly with increasing age in both sexes. The prevalence of internal anal sphincter dysfunction was 10.4% (15.5% in women, 5.1% in men). In a multivariate logistic regression model, age, mental disease, pelvic organ prolapse repair, and fecal incontinence were independently associated with a greater risk of internal anal sphincter dysfunction in women and men. Conclusions: Internal anal sphincter dysfunction is a common problem for women and men. Several of the identified risk factors are preventable or modifiable, and may direct future research in fecal incontinence therapy.

A Case of Endometriosis in Episiotomy Scar with Anal Sphincter Involvement

Endometriosis is defined as the presence of endometrial tissue apart from its usual location (endometrium). It is the second most prevalent benign gynecologic disease after the presence of fibroids in women of childbearing age (incidence of 10% - 25%). Endometriosis predominantly locates on peritoneal surfaces, but it also affects the vagina, vulva, recto-vaginal septum and perineum, usually secondary to surgical or obstetric trauma. We present a case of a patient with perineal endometriosis (single nodule) in the scar of episiotomy and involvement of external anal sphincter with local and catamenial pain but with continence maintained. The endometric nodule was removed, and wide dissection and sphincteroplasty were performed. Afterwards, treatment with GnRh analogues was prescribed for a four-month period. Surgical outcome was successful and the patient was asymptomatic during subsequent menstruations.

Impact of Selective vs Routine Midline Episiotomy and Lacerations of the Anal Sphincter

Introduction: Obstetric anal sphincter tear (OAST) is associated with anal incontinence. Episiotomy was proposed as a form of protection of the anal sphincter at delivery;however, several studies have shown that routine use of episiotomy does not reduce the risk of OAST. Objective: This study aims to analyse whether the reduction in the rate of episiotomy in a school hospital in Brazil was associated with an increase in the incidence of obstetric lacerations of the anal sphincter, in addition to associated factors. Methods: Observational, cross-sectional and retrospective study. We included all vaginal deliveries of single pregnancies, cephalic presentation, from 34 weeks of gestational age, performed in 2011-2012 (liberal episiotomy) and 2015-2016 (restricted episiotomy), and compared in relation to the rate of mediolateral episiotomy and OAST. Results: 4268 births were analysed (2043 in 2011-2012 and 2225 in 2015-2016). The episiotomy rate decreased from 59.4% to 44.2% (p ≤ 0.0001). In 2011-2012, there were 10 obstetric anal sphincter lacerations in 2043 births (0.48%), while in the period 2015-2016 there were 31 lacerations in 2225 births (1.39%). There was interaction when comparing the two periods in relation to the episiotomy and the occurrence of OAST (p ≤ 0.0001). Factors associated with OAST were labor induction and shoulder dystocia. Conclusion: There was an increase in the rate of lacerations of the anal sphincter with use of restrictive episiotomy. However, this increase occurred both in deliveries with and in deliveries without episiotomy.

Problems with repairing gut sphincters malfunctions

Correcting a gut sphincter malfunction is a difficult problem.Because each sphincter has two opposite functions,that of closure and opening,repairing one there is a risk of damaging the other.Indeed,widening a narrow sphincter,such as lower esophageal sphincter(LES)and anal sphincter,may cause gastroeso-phageal reflux and fecal incontinence,respectively,whereas narrowing a wide sphincter,may cause a difficult transit.All the corrective treatments for difficult or retrograde transit concerning LES and anal sphincter with their unwanted consequences have been analyzed and discussed.To overcome the drawbacks of sphincter surgical repairs,researchers have devised devices capable of closing and opening the gut lumen,named artificial sphincters(ASs).Their function is based on various mechanisms,e.g.,hydraulic,magnetic,mechanical etc,operating through many complicated components,such as plastic cuffs,balloons,micro-pumps,micromotors,connecting tubes and wires,electromechanical clamps,rechargeable batteries,magnetic devices,elastic bands,etc.Unfortunately,these structures may facilitate the onset of infections and induce a local fibrotic reaction,which may cause device malfunctioning,whereas the compression of the gut wall to occlude the lumen may give rise to ischemia with erosions and other lesions.Some ASs are already being used in clinical practice,despite their considerable limits,while others are still at the research stage.In view of the adverse events of the ASs mentioned above,we considered applying bioengineering methods to analyze and resolve biomechanical and biological interaction problems with the aim to conceive and build efficient and safe biomimetic ASs.

Internal anal sphincter augmentation and substitution

There is an increasing recognition of the importance of internal anal sphincter(IAS)dysfunction presenting as passive faecal incontinence.This problem may manifest after anal sphincterotomy or following the more minimally invasive operations for haemorrhoids,as well as with advancing age.Because of the poor results of IAS plication and the beneficial outcomes with peri-urethral bulking agents in urology,these materials have been developed for use in IAS dysfunction.This review outlines the basic purported mechanisms of action,defining the materials in clinical use,their methods of deployment,complications and reported outcomes.There is still much that is unknown concerning the ideal agent or the volume and the technique of deployment,which will only be answered by powerful,prospective,randomized,controlled trials.The specific role of autologous stem cells designed to regenerate the sphincters in cases of functional impairment or muscle loss is yet to be seen.

RELATIONSHIP BETWEEN INTERNAL ANAL SPHINCTER FUNCTION AND LENGTH OF REMAINING RECTUM AFTER RESECTING RECTAL CARCINOMA

Objective: To study the relationship between internal anal sphincter function and length of remaining rectum after resecting rectal carcinoma. Methods: Preoperatively, 21 patients were evaluated via patients' clinical date, including anal resting pressure (resting pressure) assay. Six months postoperatively, repeated manometric studies and clinical evaluations were performed to assess the level of continence . The formula use for calculating post operative resting pressure is as follows: postoperative resting pressure=0.42×preoperative resting pressure+1.56×length of remaining recturm+12.37(R 2=0.58; P <0.01).Degree of continence was graded based on severity of the dysfunction and grade of the continence score. Results: It was demonstrated the patients with low postoperative resting pressures (<4.0 Kpa) had incontinence, and those with high postoperative resting pressures (>4.7 Kpa) were continent. There were significant correlations between length of the remaining rectum and ratio of the decrease in maximum resting pressure (postoperative/preoperative maximum resting pressure;r=0.62; P <0.01). Conclusion: Continence of rectum is influenced by maximum resting pressure of function of the internal anal sphincter, length of remaining rectum is shorter, the more damage to the internal anal sphincter. It is able to foretell stool incontinence by using the postoperative resting pressure formula, and to determine the length of the remaining rectum.

Manometric asymmetry of the anal sphincter: anatomic evidence and clinical application

Background Manometric pressure asymmetry of the anal sphincter exists in the anal canal. There are reports about the anatomy of the anal sphincter, but the relationship between the configuration and the pressure asymmetry of the anal sphincter is not clear. This study is to investigate the anatomic evidence and clinical application of anal sphincter pressure asymmetry. Methods PC polygram HR at the state of relaxing and squeezing was used in 27 normal children and 12 abnormal ones with fecal incontinence. Results In normal children, longitudinal pressure gradients existed at eight channels in the anal canal, and the maximal pressure I cm from the anal verge. Longitudinal pressure asymmetry changes of eight channels also existed in the anal canal, from 3 cm to 2 cm to I cm from the anal verge. The high pressure distribution changed from the posterior to the anterior anal canal. Anteriorly, 1 cm from the anal verge, the maximal pressure was formed in the anal canal. However, neither longitudinal pressure gradients nor longitudinal pressure asymmetry changes were seen in patients with fecal incontinence. Conclusion The configuration and function of the striated muscle complex possibly contribute to the formation of the pressure asymmetry of the anal sphincter, which is essential to anal control.

Challenges faced in the clinical application of artificial anal sphincters

Fecal incontinence is an unresolved problem, which has a serious effect on patients, both physically and psychologically. For patients with severe symptoms, treatment with an artificial anal sphincter could be a potential option to restore continence. Currently, the Acticon Neosphincter is the only device certified by the US Food and Drug Administration. In this paper, the clinical safety and efficacy of the Acticon Neosphincter are evaluated and discussed. Furthermore, some other key studies on artificial anal sphincters are presented and summarized. In particular, this paper highlights that the crucial problem in this technology is to maintain long-term biomechanical compatibility be- tween implants and surrounding tissues. Compatibility is affected by changes in both the morphology and mechanical properties of the tissues surrounding the implants. A new approach for enhancing the long-term biomechanical compatibility of implantable artificial sphincters is proposed based on the use of smart materials.

Coupling analysis of transcutaneous energy transfer coils with planar sandwich structure for a novel artificial anal sphincter

This paper presents a set of analytical expressions used to determine the coupling coefficient between primary and secondary Litz-wire planar coils used in a transcutaneous energy transfer(TET) system. A TET system has been designed to power a novel elastic scaling artificial anal sphincter system(ES-AASS) for treating severe fecal incontinence(FI), a condition that would benefit from an optimized TET. Expressions that describe the geometrical dimension dependence of self- and mutual inductances of planar coils on a ferrite substrate are provided. The effects of ferrite substrate conductivity, relative permeability, and geometrical dimensions are also considered. To verify these expressions, mutual coupling between planar coils is computed by 3D finite element analysis(FEA), and the proposed expressions show good agreement with numerical results. Different types of planar coils are fabricated with or without ferrite substrate. Measured results for each of the cases are compared with theoretical predictions and FEA solutions. The theoretical results and FEA results are in good agreement with the experimental data.

Artificial Anal Sphincter with Sensor Feedback Powered by Transcutaneous Energy Transmission

This artificial anal sphincter (AAS) is used to help patients who are in severe incontinence. It consists of two parts. The first part is taken outside with patients. The second is implanted in the bodies to provide independent evacuation for patients. It is powered through transcutaneous energy transmission by the first part. There are two sensors in the second part. One sensor measures the pressure in the cuff-clamp around the recta. The other measures the pressure of the recta. As soon as the pressure measured by the later reaches the threshold, a signal is sent out to patients through wireless communication to alarm patients preparing defecation. Patients can give a start signal to begin defecating after they are ready. And they can also give a signal to stop defecating like a healthy person. With the aids of the novel medical device, patients can defecate as a healthy person. The first generation of this AAS is presented.

Electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter system

This paper reports on the electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter.The coupling coils and human tissues,including the skin,fat,muscle,liver,and blood,were considered.Specific absorption rate (SAR) and current density were analyzed by a finite-length solenoid model.First,SAR and current density as a function of frequency (10–107 Hz) for an emission current of 1.5 A were calculated under different tissue thickness.Then relations between SAR,current density,and five types of tissues under each frequency were deduced.As a result,both the SAR and current density were below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).The results show that the analysis of these data is very important for developing the artificial anal sphincter system.

Milligan-Morgan hemorrhoidectomy with anal cushion suspension and partial internal sphincter resection for circumferential mixed hemorrhoids

AIM:To identify a more effective treatment protocol for circumferential mixed hemorrhoids.METHODS:A total of 192 patients with circumferential mixed hemorrhoids were randomized into the treatment group,where they underwent Milligan-Morgan hemorrhoidectomy with anal cushion suspension and partial internal sphincter resection,or the control group,where traditional external dissection and internal ligation were performed.Postoperative recovery and complications were monitored.RESULTS:The time to wound healing was 12.96 ± 2.25 d in the treatment group shorter than 19.58 ± 2.71 d in the control group.Slight pain rate was 58.3% in the treatment group higher than 22.9% in the control group;moderate pain rate was 33.3% in the treatment group lower than 56.3% in the control group severe pain rate was 8.4% in the treatment group lower than 20.8% in the control group.No edema rate was 70.8% in the treatment group higher than 43.8% in the control group;mild local edema rate was 26% in the treatment group lower than 39.6% in the control group obvious local edema was 3.03% in the treatment group lower than 16.7% in the control group.No stenosis rate was 85.4% in the treatment group higher than 63.5% in the control group;moderate stenosis rate was 14.6% in the treatment group Lower than 27.1% in the control group severe anal stenosis rate was 0% in the treatment group lower than 9.4% in the control group.CONCLUSION:Milligan-Morgan hemorrhoidectomy with anal cushion suspension and partial internal sphincter resection is the optimal treatment for circumferential mixed hemorrhoids and can be widely applied in clinical settings.