Hpall endonuclease distinguishes between two species in the Anopheles funestus group

New surgical treatment modalities have been developed for patients with anal incontinence resulting from extensive sphincter destruction and in whom standard sphincter repair has failed. These new modalities include the transposition of striated skeletal muscles combined with implantation of neurostimulators, artificial sphincters based on the same principle as artificial urinary sphincters, and direct sacral nerve stimulation. In a few reported series muscle transposition in combination with neurostimulation has given a satisfactory continence in 50-70% of the patients. The same is true for the smaller series published on artificial anal sphincters, whereas the results of sacral nerve stimulation have thus far been reported in only a few patients. The selection of patients and the performance of these procedures should be limited to few specialist centres.     

The longitudinal muscle of the anal canal

The longitudinal muscle (LM) represents a strong muscular structure of the anal canal situated between the internal (IAS) and the external anal sphincter (EAS). Terminal fibres of this muscle insert at the submucosa of the anal canal, representing the m. canalis ani. Others cross the subcutaneous part of the EAS to become the m. corrugator ani. Thus, the LM connects the visceral and somatic parts of the anal sphincter complex. Histologically ganglionic cells and as Vater-Pacinian corpuscles can be identified inside the LM. Morphology, topography and histology of the LM suggest that this muscle participates in maintaining anorectal continence. It is mandatory that the exact functions of this muscular structure be to elaborated upon, if we are to understand the mechanism of anorectal continence.     

Possible role of the autonomic nervous system in sphincter impairment after restorative proctocolectomy

Peroperative manometry was performed in 12 patients operated on with endoanal proctectomy and a hand-sewn pouch-anal anastomosis and in 12 in whom proctectomy was performed entirely from above, with the ileal pouch stapled to the top of the anal canal. Results from both groups showed that division of the superior rectal artery reduced the median (95 per cent confidence interval (c.i.)) resting anal pressure from 77.5 (69.9-83.3) mmHg to 64.5 (55.2-70.0) mmHg (P < 0.01). Complete rectal mobilization to the pelvic floor decreased resting pressure by an additional 22 per cent, to a median of 50.0 (95 per cent c.i. 40.1-53.5) mmHg (P < 0.01). After completion of anastomosis, irrespective of the operative technique used, a further decline in median pressure to 35.0 (95 per cent c.i. 26.0-47.7) mmHg could be demonstrated (P < 0.05). This study indicates that anal sphincter pressure is reduced to a similar extent after hand-sewn and stapled anastomoses. Injury to the autonomic nervous supply to the anal sphincter mechanism might be the major cause for this reduction.     

Muscle transformation of the sartorius muscle in a canine model: clinical impact for electrodynamic graciloplasty as a "neosphincter"

PURPOSE: Transformation of fast-twitching skeletal muscles to slow-twitching, slowly fatigable muscles has become of clinical interest in the recent past. Transposition and transformation of the gracilis muscle to use it as a substitute for a resected or defected anal sphincter (graciloplasty) have been reported as achieving promising results in the treatment of fecal incontinence caused by sphincter defects or following abdominoperineal anorectal excision for cancer. METHOD: This experimental study used a canine model and the sartorius muscle to evaluate the functional efficiency of two different configurations of the muscle loop to compare the presently applied transformation program (8 weeks) with a shorter (5 weeks) protocol. In six beagle dogs, both sartorius muscles were wrapped around two stomas, either in an alpha fashion or in the so-called split-sling technique. Muscle transformation was achieved by controlled neuromuscular stimulation either during eight (Program A) or five weeks (Program B). After completion of the transformation period, the function of the muscle slings was evaluated by manometry, and histomorphologic evaluation of the sartorius muscles was performed. RESULTS: It was shown that muscle transformation led to a slowly fatigable muscle that made it possible to perform continuos (tetanic) contraction, regardless of the configuration or the duration of the transformation. Median pressures created by these muscles also did not differ significantly. In accordance with these functional findings, the histologic evaluation showed the typical, significant increase of Type I fibers in both muscle slings and following both transformation protocols. Although the decrease of fast-twitching Type II fibers was more pronounced following the conventional (8 weeks) program, this finding did not influence the functional results. CONCLUSIONS: Results of our experiment indicate the possibility for using a shorter transformation protocol for transformation of the gracilis muscle during graciloplasty in the clinical setting. Furthermore, the efficacy and safety of the modified (split-sling) wrap technique was demonstrated.     

Prospectively evaluating anal sphincter function after ileal pouch-anal canal anastomosis

The decreased anal sphincter pressure that occurs after ileal pouch-anal canal anastomosis (IPAA) has usually been attributed to damage of the internal and sphincter. We hypothesized that the operation damages both the internal and the external anal sphincter. Resting pressure in the anal canal (a function of internal and external sphincters), anal squeeze pressure (a function of external sphincter only), and the rectal-anal inhibitory reflex (involving the internal sphincter) were measured manometrically in 10 patients with ulcerative colitis (4 women and 6 men; mean age, 33 years; range: 20 to 49 years). The patients were studied while awake before IPAA, under general anesthesia with striated muscle blockade just before incision, awake 2 months later before ileostomy takedown, and again under anesthesia with blockade just before takedown. The operation decreased maximum resting anal pressure while awake and during anesthesia with blockade. The decrease was detected in the proximal anal canal but not in the distal anal canal. In addition, the operation impaired anal squeeze pressure and abolished the rectal-anal inhibitory reflex. We conclude that IPAA damages both the internal and the external anal sphincter.     

On the surgical treatment of refractory epilepsy in tuberous sclerosis complex

Using the pig as a model, it was shown that stimulation of the distal nerve ending of the pudendal nerve leads to the isolated stimulation of the external anal sphincter muscle. No difference in pressure response was noted after application of between 0.5 and 1.5 mA unilateral or bilateral stimulation. Major advantages observed using between 1.5 and 2.5 mA bilateral stimulation; with a stimulation between 2.0 and 2.5 mA the pressure response was twice as high compared to unilateral stimulation. Continuous stimulation of the striated anal sphincter muscle leads to fatigue, reaching 50% fatigue after a median time between 40-90 s. In cyclic stimulation (alternation every 15 s, duration 20 min) a fatigue reaction was also seen. The peak pressure decreased after 20 min for a median of 11%, the final pressure was lowered in 15% following a logarithmic curve pattern. The experimental application of variable impulse ranges also caused pressure differences. Increasing the impulse range from 200 to 450 microseconds (peak pressure) vs. 400 microseconds (final pressure) resulted in a statistically significant pressure increase. Therefore, it was proven that selective stimulation of the external anal sphincter muscle can lead to a transient pressure increase, which possibly improves fecal continence.     

Physiology of ileal pouch-anal anastomosis. Current concepts

PURPOSE: Increasing experience with ileal pouch-anal anastomosis (IPAA) associated with increasing knowledge about anorectal physiology has lead to a large number of publications. The purpose of this review is to evaluate the current understanding of fecal continence as revealed by the evolution of the ileoanal procedure. METHODS: Review of the literature covering the most important physiologic parameters involved in fecal continence was undertaken. RESULTS: Rectoanal inhibitory reflex is probably absent after IPAA but is preserved when distal anorectal mucosa is spared. Anal resting pressure decreases but is less affected when the internal anal sphincter is less traumatized. Squeeze pressure is not importantly affected, and the importance of reservoir function as a determinant of stool frequency is emphasized. IPAA does not affect the coordination between pouch and anal canal motility in the majority of cases. Normal continence is preserved, even during the night, by preserving a gradient of pressure between the pouch and anal canal. CONCLUSIONS: Physiologic concepts are well established, but controversies about the continence mechanism related to IPAA remain. The IPAA procedure has allowed discrimination of details about the function of multiple structures involved in fecal continence.     

Treatment of Adamantiades-Beh?et disease with systemic interferon alfa

PURPOSE: The aims of the study contained herein were to analyze the efficacy and safety of a chronically electrostimulated double-wrap graciloplasty for restoration of continence after a curative abdominoperineal resection for rectal carcinoma and to evaluate late results of a stimulation protocol that was begun early. METHODS: During the last six years, 31 consecutive patients underwent this procedure: in 24 patients, electrostimulated double-wrap graciloplasty was performed simultaneously with abdominoperineal resection for lower rectal cancer, 7 strictly selected patients underwent conversion to an abdominal stoma following previous abdominoperineal resection (mean length of time from stoma creation, 71.4 months) Anorectal reconstruction was performed following a surgical scheme already standarized since 1985 in 102 patients: after abdominoperineal resection, the distal colon was pulled through to the perineum and surrounded by both gracilis muscles following an "alfa and new-sling" configuration; using platinumiridium electrodes, both muscles were then connected to pulse generator, which was implanted subcutaneously in the abdomen. All surgical steps were performed during the same surgical session to allow early postoperative stimulation of the transposed muscles. A contemporary covering stoma was abandoned as a standard procedure; the distal colon was left closed for a few postoperative days, then it was resected and sutured to the perineum under local anesthesia. Eighteen patients underwent preoperative or postoperative radiotherapy or both, without any significant adverse outcome. To increase gracilis resistance to prolonged "tonic" contraction, patients underwent a chronic, low-frequency stimulation protocol. In the last 11 patients, a new "over-the-nerve and intramuscular" implant was adopted to optimize fiber recruitment and to reduce electrostimulation thresholds. At regular intervals, all patients were evaluated using continence scores and questionnaires, electromanometry, endoluminal ultrasound study, and defecography. RESULTS: Twenty-six of 31 patients were evaluated for continence, with a mean length of follow-up of 37.8 (range, 4-68) months; 3 patients died because of cancer recurrence, 1 underwent conversion to an abdominal stoma, and 1 is waiting for stoma closure. Continence to liquid and solid stools was achieved in 22 patients (85 percent), and electromanometry findings confirmed a good muscular contraction postoperatively and during follow-up intervals. No postoperative mortality (40 days) was observed; the postoperative complication rate was high 22-percent), but early treatment (drainage and temporary diversion in 7 patients) led to favorable outcomes (4 resolutions, 3 partial muscular impairments). Four stimulators had to be temporarily explanted because of late complications, and two stimulators had to be replaced because of battery exhaustion after three years of use with high stimulation parameters. A significant difference was observed comparing full-contracting threshold after intramuscular (14 patients) and the new over-the-nerve and intramuscular implant technique. CONCLUSIONS: The study contained herein confirms the efficacy of the surgical scheme we have adopted since 1985 to reconstruct sphincteric apparatus after abdominoperineal resection of the rectum. The "one-step" timing of surgical and electrostimulation-related procedures and the early start of stimulation did not show a significant increase in the complication rate and did not produce noticeable muscular or nerve damage. Adoption of chronic electrostimulation protocols using implantable devices increased the rate of fully continent patients; nevertheless, the overall cost for devices and medical staff duties was high, and a small increase of late morbidity was observed. Finally, the preliminary experience with our new technique of electrode implants encourages further application.     

Electrically stimulated colonic reservoir for total anorectal reconstruction

Total anorectal reconstruction after abdominoperineal excision of the rectum has failed to achieve perfect continence. Electrically stimulated reservoir evacuation in combination with an electrically stimulated gracilis neoanal sphincter might improve results. A J pouch was constructed in an isolated colonic loop of seven dogs. Bipolar square wave pulses were delivered via two intramural stainless steel electrode pairs at 10 Hz. Stimulation parameters were varied to achieve adequate contraction. Serosal strain gauges recorded spontaneous and stimulated pouch motility. Evacuation was quantified by a volume displacement technique and observed fluoroscopically. Recordings were performed for a median of 3 (range 1-11) months. At 10 Hz and 0.5 ms pulse width, stimulation was required for 2 min and at voltages of 15 V (n = 4), 18 V (n = 1) and 20 V (n = 2) to obtain a contraction of amplitude comparable to that of a spontaneous contraction. Suprathreshold stimulation invariably resulted in colonic pouch contraction. The mean(95 per cent confidence interval (c.i.)) stimulus-response latency was 25.5(1.9) s. The mean(95 per cent c.i.) intraluminal pressure generated during stimulation was 114.1(17.0) cmH2O and 64.6(12.0) cmH2O during spontaneous activity (P < 0.001). In conclusion, electrical stimulation via intramural electrodes produced contraction generating sufficient intraluminal pressure to effect evacuation of a canine colonic pouch. This has potential for incorporation with an electrically stimulated neoanal sphincter in total anorectal reconstruction to improve evacuation and continence.     

How reproducible are measures of the anal sphincter muscle diameter by endoanal ultrasound?

Anal endosonography is an imaging technique for the anal sphincter system and offers analysis of its muscular integrity. It is generally assumed that measurement of the thickness of muscle layers is provided by sonography; however, reproducibility of such measurements have not yet been investigated. METHODS: Study 1: In 10 healthy volunteers, endoanal ultrasound was performed independently by two experienced investigators with two different ultrasound machines, and thickness of the muscle layers of the internal and external anal sphincter was assessed in the position of the intermediate dorsal anal canal in a randomized cross-over fashion. Study 2: In a study of similar design, sonography was performed in nine healthy volunteers by two investigators independently using a single ultrasound machine in three standardized positions (proximal/intermediate/distal anal canal) and the sphincter layers assessed in the left, right, and dorsal segment. RESULTS: Study 1: Both the same investigator with different ultrasound scanners and different investigators with the same machine failed to obtain reproducible results with respect to internal and external anal sphincter muscle layer diameter (four bivariate correlations, all with p > 0.05). Study 2: Standardization of the probe position did not improve the agreement (2 x 9 bivariate correlations, all but two p > 0.05). CONCLUSION: At present, therefore, endoanal ultrasound does not provide reliable morphometric data on anal sphincter muscle diameter. This could explain previously conflicting observations of associations between anal sphincter morphometry and function.     

Diagnosis and management of fecal incontinence in elderly patients

Fecal incontinence is a physically and psychologically disabling condition that affects millions of Americans, especially those over the age of 65 years. The pathophysiology is often multifactorial, with decreased anorectal sensation, reduced rectal compliance. anal sphincter dysfunction, altered stool consistency and immobility playing significant roles. A detailed history and a thorough physical examination are always necessary in patients with fecal incontinence and physiologic tests, including anorectal manometry, cinedefecography and electromyography, may be required for proper diagnosis and treatment. In most patients fecal incontinence is initially treated with conservative measures, such as biofeedback training or alteration of the stool consistency (if appropriate). If conservative management fails, surgical intervention, such as sphincteroplasty or gracilis muscle transposition, may be considered.     

In vitro shear strength of bonded amalgam cores with and without pins

After ileo-pouch-anal anastomosis (IPAA) there is an increased risk of incontinence due to intraoperative damage of the anal sphincter. We present a new concept to identify a potential incontinence prior to the closure of ileostomy by clinical and anal manometrical examinations. In 11 of 121 (9.1%) patients we diagnosed a potential incontinence. By biofeedback training we could achieve in this way a sufficient continence after the closure of ileostomy. After an average of 5.0 +/- 4.3 months of training rest pressures improved from 19.3 +/- 2.1 mmHg to 33.0 +/- 3.5 mmHg and squeeze pressures from 60.5 +/- 27.7 mmHg to 93.5 +/- 17.3 mmHg. Prior to IPAA patients with potential incontinence show significantly reduced rest pressures of 51.0 +/- 18.4 mmHg.     

Randomized trial comparing three forms of pelvic floor repair for neuropathic faecal incontinence

A randomized controlled trial in women with neuropathic faecal incontinence compared total pelvic floor repair (n = 12) with anterior levatorplasty and sphincter plication alone (n = 12) and postanal repair alone (n = 12). Review at 6 and 24 months indicated that results were significantly better for total pelvic floor repair than either of the other procedures. Complete continence was achieved in eight of the 12 patients 2 years after total pelvic floor repair. Only total repair significantly elongated the anal canal. Both total pelvic floor repair and anterior levatorplasty improved sensation in the upper anal canal.     

Clinical effects of childbirth with median episiotomy and anal sphincter injury on fecal incontinence of primiparous women

Obstetric damage of the anorectal continence organ can lead to impaired anal continence. To assess the effect of birth, either with or without direct injury of the anal sphincter, 123 primiparae were studied. 41 patients with a midline episiotomy and 82 patients with an additional injury of the anal sphincter were assessed at a median of 21 weeks postpartum and compared with 18 healthy volunteers. Anorectal manometry as well as a standardized questionnaire were employed. Patients with an additional injury of the anal sphincter reported persistent flatus incontinence significantly more often (p = 0.0069) than patients with a midline episiotomy only. Incontinence of solid or liquid stool occurred only transiently. Compared to nulliparae in all primiparae a significant shortening of anal canal and a decreased squeeze pressure were observed. In addition, a significantly reduced resting pressure was seen in patients with an anal sphincter injury. The rectoanal inhibitory reflex was absent significantly more often following anal sphincter tear (p = 0.0023). Vaginal delivery, both with and without anal sphincter injury, leads to early detectable changes in anorectal sphincter function.     

Gluteus maximus augmentation for the treatment of fecal incontinence

Fecal incontinence is a devastating problem for school-aged children and adults. Medical and biofeedback therapies are unsuccessful in most patients who have severely defective internal and external sphincters. Continued fecal incontinence frequently leads to social isolation and withdrawal. Gluteus maximus augmentation of the sphincter mechanism is one surgical method for treating fecal incontinence. The authors present their results with gluteus maximus augmentation of the anal sphincter and describe patient selection criteria. From 1992 through 1996, seven patients underwent gluteus maximus augmentation of the anal sphincter for fecal incontinence. Six of these patients were children 5 to 6 years of age who had major deficiencies of their anorectal sphincter demonstrated by manometry. One patient was a 56-year-old adult woman who had acquired idiopathic fecal incontinence. Four of the six children (67%) had imperforate anus and two had cloacal anomalies (33%). The augmentation was performed in three stages. A sigmoid-end colostomy with a Hartman's pouch was followed 1 month later by rotation of a portion of the gluteus maximus for anorectal sphincter augmentation. A colostomy take down was performed 2 to 4 months later. All patients underwent dilatation after sphincter augmentation and were taught muscle exercises for using their neosphincter during the period before colostomy take down. Four of six children and the adult are continent postoperatively (71%). Both patients who remain incontinent are unable to sense rectal distention clinically or on anal manometric analysis but have excellent voluntary sphincter tone. Fecal incontinence can be successfully treated with gluteus maximus augmentation in carefully selected patients. Patients unable to sense rectal distension are unlikely to benefit from this procedure. The presence of a rectal reservoir and a skin-lined anal canal also appear to be important in attaining fecal continence.     

Endo-anal sonography in diagnosis of fecal incontinence

Endoanal ultrasound is a new imaging technique in the diagnostic work-up of patients suffering from anal incontinence. A standardised examination as well as hardware specific reference values for the sphincter muscles are of paramount importance to allow correct interpretation of the continence organ. At the University Hospital of Würzburg from 1.2.1993 to 31.7.1994 90 patients (50 male, 40 female; age: 16-81 y.) with normal continence underwent endosonographic assessment of their sphincter complex. We measured the internal anal sphincter (IAS), puborectalis muscle as well as the three separate parts of the external anal muscle (EAS). Apart from establishing reference values we found a significant increase in thickness of both EAS and IAS with increasing age. However, no correlation was seen between muscle thickness, sex, height or weight. We also examined 29 patients with a history of incontinence. 13 (45%) had a morphological sphincter defect, most of which were due to obstetric trauma or previous proctological operations. 10 (35%) patients suffered from so called idiopathic incontinence. Anal ultrasound in these patients revealed muscle hypotrophy of the structurally intact sphincters.     

Cutting seton for anal fistulas: high risk of minor control defects

PURPOSE: Long-term results of cutting seton in the treatment of anal fistulas were studied. METHODS: Of the 44 patients with anal fistulas, mainly of the high variety, managed with this method, 35 (25 men) attended a clinical and manometric follow-up examination on average 70 (range, 28-184) months after operation. Fistula distribution was high transsphincteric (25), low transsphincteric (5), extrasphincteric (3), and suprasphincteric (2). The seton was tightened at one-week to two-week intervals to achieve gradual sphincter division. RESULTS: Time required to achieve complete fistula healing ranged from 37 to 557 (mean, 151) days. Two (6 percent) of the 35 patients re-examined had recurrence of fistula and 22 (63 percent) reported symptoms of minor impairment in anal control, which in four patients had existed already before operation. Anal resting pressures were similar for defective and normal control, but other manometric variables were inferior in incontinence, although total squeeze pressure only showed statistically significant difference from normal continence (P = 0.0345). Incontinence was likely associated with hard and gutter-shaped operation scars in the anal canal, but the difference from normal continence was not statistically significant. CONCLUSION: Cutting seton yields fairly good results in regard to cure of fistula, but the risk of anal incontinence, despite its minor degree, seems to be too high to recommend its routine use for all high fistulas. The suprasphincteric fistulas and some extrasphincteric fistulas are difficult to treat otherwise, but especially for high transsphincteric fistulas, other methods of treatment (preferably those in which sphincter division can be avoided and the risk of anal canal deformity and incontinence are minimized) are advocated.     

Fiber type composition of abdominal muscles in Japanese macaques (Macaca fuscata)

The muscle fiber composition and cross-sectional area of muscle fiber types were investigated histochemically in the abdominal muscles (rectus abdominis muscle, obliquus externus abdominis muscle, obliquus internus abdominis muscle and transversus abdominis muscle) of three Japanese macaques (Macaca fuscata). Muscle fibers were classified into three fiber types (Type I, II A and II B) by myosin ATPase activity and succinate dehydrogenase activity. Each abdominal muscle in Japanese macaques contained high proportion of Type II B fibers and there were no large differences in the fiber type composition between the abdominal muscles. The range of mean fiber type percent was 26-32% Type I, 21-22% Type II A, and 46-52% Type II B fibers. Thus, based on the histochemical fiber type composition, the separate abdominal muscles appear to have a similar functional capacity. The cross-sectional area was larger for Type II than for Type I fibers, and the areas were similar in Type II A and Type II B fibers in each muscle. The rectus abdominis showed larger fibers of each type compared to the lateral abdominal muscles. The high proportion of Type II B fibers and large fiber size for Type II B fibers suggest that the abdominal muscles of Japanese macaques have properties similar to the propulsive and locomotory muscles in the limbs.     

Effects of anal invasive treatment and incontinence on mental health and psychosocial functioning of adolescents with Hirschsprung's disease and low anorectal anomalies

BACKGROUND/PURPOSE: Recent studies of adolescents with Hirschsprung's disease (HD) and low anorectal anomalies (LARA) showed persistent impairment of fecal control in both groups, but very different mental and psychosocial outcome. METHODS: To explore possible reasons for these differences, 19 adolescents with HD (aged 10 to 20 years; median, 16) operated on by the Duhamel technique were compared with 17 adolescents with LARA (aged 12 to 20 years; median, 15). The 36 adolescents were assessed for treatment procedures, bowel function, and mental and psychosocial outcome by data collected from medical records, physical examination, semistructured interview, and standardized questionnaires. The parents of 30 adolescents were also interviewed and completed questionnaires. RESULTS: Duration of anal invasive treatment procedure and current bowel function were associated with mental and psychosocial outcome. The treatment variable, duration of anal dilation, was the most significant predictor of the adolescents's mental health (R2 = .41, P < .01), whereas chronic family difficulties and parental warmth together with the current bowel function variables, fecal and flatus continence function, best explained the variance in psychosocial outcome (R2 = .77, P < .0001). Thus, the differences in treatment procedures and continence function between the HD and LARA groups may partially explain differences in mental and psychosocial outcome. CONCLUSIONS: These findings suggest that anal dilatation and continence dysfunction may have negative impact on mental health and psychosocial functioning. Indications for and ways of performing the procedure of dilation, and the treatment of persistent incontinence problems, are questioned.     

Adjusting the geometry of implantable hearing aid components to human temporal bone. II: Microphone

Prerequisite to implantation of a piezoelectrical transducer of an implantable hearing aid is a shape allowing its implantation into human mastoid and middle ear. To approach this problem, a consecutive series of six transducer prototypes was created in an iterative process. Their functional geometry was evaluated in 50 human temporal bones. A shape for a functioning transducer was found which will enable implantation in 78% of the cases examined (confidence interval: 61.5%-89.2%). It will allow simultaneous implantation of the transducer into the mastoid and microphone, which is situated transmastoidal in the posterior wall of the ear canal. Furthermore, the transducer may be coupled to the ossicular chain or the perilymph.