Anorectal manometry (ARM) is a common diagnostic tool for fecal incontinence and constipation. However, it can also be used within care pathways for a number of disorders, which will be described here.
What is Anorectal Manometry?
As a diagnostic test, ARM is utilized to evaluate bowel function in patients that are suffering from either fecal incontinence or chronic constipation. A small balloon is attached to a catheter that is inserted into the rectum. The balloon is distended and measurements such as anal sphincter strength, rectal sensation, bowel reflexes, and the movements of anal and rectal muscles are recorded.
There are a number of tests that are commonly performed during an ARM examination. Anal sphincter electromyography utilizes surface electrodes to measure sphincter muscle strength when the patient relaxes, squeezes, and pushes the muscles in the anus and pelvic floor.
Anorectal rest and squeeze pressure profiling utilizes a 4-channel radial air-charged anorectal catheter that is inserted 4 cm into the patient’s rectum. The catheter is slowly removed one centimeter at a time while resting and squeezing pressures are recorded in the anterior, right, posterior, and left quadrants of the rectum.
Rectal volume measurements are performed by inserting a rectal balloon and slowly filling it with water to assess rectal sensations such as volume required for first urge to defecate and the maximum tolerable rectal volume.
Rectoanal inhibitory reflex can also be measured, which determines the transient relaxation of the internal anal sphincter relative rectal distention.
Finally, a balloon expulsion test is typically performed, whereby a balloon is inserted into the patient’s rectum and filled with water or air. The patient is then asked to expel the balloon to determine whether anorectal dysfunction is evident.
Anorectal Manometry and Biofeedback
For patients with certain conditions, such as fecal incontinence or constipation, the sphincter and rectal muscles do not relax and contract properly, resulting in improper storage and release of stool. Anorectal biofeedback is a treatment plan that retrains these muscles for proper use. In general, anorectal biofeedback enables abdominal, rectal, anal sphincter, and pelvic floor muscles to coordinate for proper defecation.
An anorectal manometry probe is inserted into the rectum and the patient is provided visual or auditory feedback regarding his or her anorectal muscular function. Feedback is provided either by micro transducers that are attached to the manometry probe with a balloon, or a water perfused probe that contains multiple side holes.
In conjunction with operant conditioning, i.e. reinforcement of the proper behavior (in this instance, proper use of muscles), a person can retrain his or her bowels to overcome dyssenergia. Most patients are able to retrain their bowel habits with six, 1-hour biofeedback sessions during a 3 month time period.
Care Paths That Leverage Anorectal Manometry (ARM)
There are numerous care pathways that utilize ARM and biofeedback. A summary of each disorder, as well as the manner in which ARM is used, will be described.
Delayed Rectal Sensation
Fecal incontinence can occur as a result of poor sensation in the rectum, causing individuals not to realize a bowel movement is imminent. A successful form of treatment for delayed rectal sensation is anorectal manometry retraining.
In a study entitled Delayed Rectal Sensation with Fecal Incontinence: Successful Treatment using Anorectal Manometry1, researchers found that 28% of patients that were referred for fecal incontinence had delayed conscious rectal sensation that correlated with internal sphincter relaxation.
This condition was diagnosed via balloon distension during an anorectal manometry test, and treatment also utilized this technique. Neuromuscular retraining with balloon distention had numerous positive outcomes in this study.
There was a significant correction of rectal sensory delay by 2 – 22 seconds, which resulted in the elimination of fecal incontinence in some patients. For 10 of 13 patients, an improved sensory threshold was reported. This study addressed a sensory abnormality that was previously unreported and suggested a simple solution that had promising results.
Fecal incontinence affects a surprising number of people; however this disorder is rarely discussed. In the following study, Randomized, Controlled Trial of Biofeedback with Anal Manometry, Transanal Ultrasound, or Pelvic Floor Retraining with Digital Guidance Alone in the Treatment of Mild to Moderate Fecal Incontinence2, the use of ARM for the treatment of fecal incontinence was reviewed.
There are a number of treatment pathways available for people with fecal incontinence. One such technique is pelvic floor exercises with biofeedback utilizing ARM, which helps individuals learn to contract and relax the proper muscles for stool storage and release.
Transanal ultrasound is another option, which provides visual feedback for the retraining of the rectal muscles. Additionally, pelvic floor exercises with feedback from digital examination can also be performed. The manner in which these treatment options affect continence outcomes, quality of life, sphincter strength, and compliance were examined.
A total of 120 patients with mild to moderate fecal incontinence were placed into one of three treatment groups: biofeedback with ARM, biofeedback with transanal ultrasound, and pelvic floor exercises with feedback from digital examination.
Seven days after an initial 45 minute examination, patients attended monthly treatment sessions for five months. Each session was 30 minutes in duration and utilized sphincter exercises with biofeedback. Patients were also asked to perform exercises twice per day on their own.
Of the patients that completed the entire study (102 total), all of the fecal incontinence sufferers experienced improvements in their condition, regardless of treatment pathway. Most notably, 70% of patients experienced improvement in symptom severity, while 69% of patients reported improvements to their quality of life.
Although there were no significant differences among the three care paths, this study showed that ARM is effective for improving sphincter strength and quality of life in patients with fecal incontinence. Among the three methods, ARM provides an option that could be more psychologically comfortable for patients than digital feedback, and involves less expensive equipment than when transanal ultrasound is utilized.
Ultimately, this study confirmed that pelvic floor retraining programs can be used to improve physiologic, clinical, and quality of life measurements for fecal incontinence sufferers in a short period of time.
Levator Ani Syndrome
Levator ani syndrome, also called levator spasm, chronic proctalgia, piriformis syndrome, puborectalis syndrome, pelvic tension myalgia, levator syndrome, or proctodynia, is characterized by periodic and intense rectal pain that is caused by spasm of the levator ani muscle. Typical symptoms include a dull ache located approximately 2 inches above the anus and a feeling of continual pressure or burning. In a study titled Biofeedback is effective treatment for levator ani syndrome3, treatment of this disorder with ARM was discussed.
A total of 16 patients (9 men and 7 women with an average age of 50.1 years) that suffered from levitor ani syndrome were treated with biofeedback for a period of 2 years and 3 months. Patients in this study had experienced pain for an average of 32.5 months. All patients underwent complete biofeedback with a manometric balloon. A follow up exam occurred approximately 12 months later. Before and after the study, pain score and anorectal physiology tests were administered.
Following ARM biofeedback, pain scores for each patient were significantly improved. Prior to the study, the median pain score was 8; after biofeedback, median pain score was 2, on a scale of 1 – 10. Additionally, analgesic requirements for pain management were reduced.
Whereas all 16 patients required NSAID pain relief prior to the study, only 2 patients reported their use following biofeedback. After biofeedback there were no significant changes to the anorectal physiology parameters of the patients, and no side effects or regressions were reported with follow up examinations. Ultimately, biofeedback with ARM was shown to be effective for pain relief in levitor ani syndrome.
Paradoxical Puborectalis syndrome
Paradoxical puborectalis syndrome is a condition that is related to hypertrophy of the puborectalis. When an individual sits to pass stool, the puborectalis muscle relaxes to allow for a bowel movement. However, with paradoxical puborectalis syndrome, the puborectalis does not relax when the individual bears down to pass stool, and it instead strongly contracts. Rectal pain and chronic constipation are two characteristics of this disorder.
Not only can ARM be used for the diagnosis4 of paradoxical puborectalis syndrome, but biofeedback is an important tool for the treatment of this disorder. In Biofeedback retraining in patients with functional constipation and paradoxical puborectalis contraction: comparison of anal manometry and sphincter electromyography for feedback5, ARM was studied as a possible course of treatment for patients with constipation caused by paradoxical puborectalis contraction.
A total of 26 patients with paradoxical puborectalis syndrome were randomly assigned to a treatment method utilizing one of two feedback modes: sphincter electromyography (EMG) with surface electrodes or anal pressure utilizing a manometry probe.
Of the original 26 individuals, 20 in total were able to complete the training, with ten in each feedback group. For 80% of the patients in the ARM feedback group, paradoxical puborectalis contractions disappeared after retraining, while the same results were experienced for 100% of the patients with electromyography treatment.
An overall improvement in symptoms was reported for 60% of the ARM group, while 90% experienced similar improvements in the EMG group. For both groups of patients, bowel function and abdominal symptoms significantly improved and continue to do so as observed in follow up appointments. In terms of efficacy, there was no difference between the two feedback methods.
While additional research may be warranted with larger groups of participants, this preliminary study indicated that both manometry and EMG are effective in improving symptoms of paradoxical puborectalis contraction as well as anorectal function.
Meningomyocele is a type of spina bifida where the spinal canal and backbone do not fully close before an infant is born. Children with this condition often suffer from fecal incontinence as a result of this disorder.
In a study entitled Use of Biofeedback in Treatment of Fecal Incontinence in Patients with Meningomyocele6, anorectal manometry as a biofeedback tool was studied. Fourteen children between the ages of 5 and 17 with meningomyelocele and poor bowel control first underwent anorectal manometry to determine anorectal functioning. Of the initial 14 children, eight of these patients underwent biofeedback conditioning.
The patients were taught how to contract the external anal sphincter or gluteal muscles as a function of various levels of rectal distention. Of those 8 patients, 4 had good clinical outcomes, judged by 75 – 100% decrease in soiling frequency. Criteria for success in this study included normal threshold of rectal sensation as well as the ability to contract gluteal or sphincter muscles.
Ultimately, this study showed that ARM is useful for biofeedback conditioning and is a safe and simple method for treating children with neurogenic anal sphincter dysfunction.
Pelvic Floor Dyssynergia Constipation
Pelvic Floor Dyssynergia is a condition that occurs when the external anal sphincter and the puborectalis muscles contract instead of relax during an attempted bowel movement. This contraction results in chronic constipation among sufferers.
A study titled Randomized, Controlled Trial Shows Biofeedback to be Superior to Alternative Treatments for Patients with Pelvic Floor Dyssenergia-Type Constipation7 was performed in order to determine whether biofeedback was more effective than the typical treatment for this disorder. Here, participants received either biofeedback treatment, diazepam, or received a placebo.
A total of 117 patients participated in a four week course of treatment that involved education and medical management on their disorder. Of the 84 patients that remained constipated, 30 patients were randomly selected for biofeedback training, another 30 patients were placed in a diazepam group, and the remaining 24 were given a placebo. All of the patients, regardless of their group, were trained to do pelvic floor muscle exercises during six biweekly one-hour sessions. However, only the biofeedback patients received electromyographic feedback during their exercises.
Prior to treatment, the three groups of patients did not differ significantly based on demographic, physiologic, or psychologic qualities, their severity of constipation, or their expectations of benefit.
The patients that underwent biofeedback has better results than the participants that received diazepam, with 70% reporting adequate relief of constipation versus 23%, respectively (38% of the placebo group reported adequate results). Additionally, the biofeedback patients reported more unassisted bowel movements at follow up exams than the diazepam and placebo groups.
Ultimately, this study provided definitive support for biofeedback retraining for pelvic floor dyssenergia and showed that this care path is essential for successful treatment of the disorder.
In some instances, ARM and biofeedback training may not provide better outcomes than conventional treatment, but can still have utility. Constipation is commonly seen in children, and it can be difficult to both diagnose and treat. In approximately 50% of chronically constipated children, the tendency to contract external sphincter muscles instead of relax them during defecation is observed.
While biofeedback training can change a child’s defecation behavior, there is no evidence to support that biofeedback training has any additional effect in comparison to conventional treatment on clinical outcome. The authors of the study described here, titled The Effect of Anorectal Manometry on the Outcome of Treatment in Severe Childhood Constipation: A Randomized, Controlled Trial8 sought to understand whether the use of manometry during conventional treatment for basal manometric data inadvertently caused improvements in chronically constipated children. For purposes of this study, conventional treatment referred to dietary advice, defecation diary, toilet training, enemas, and oral laxatives. Conventional treatment with manometry was compared to conventional treatment alone.
A total of 212 constipated children (143 boys and 69 girls) that were referred to a pediatric gastroenergologist were randomly assigned to a conventional treatment (115 patients) pathway or a conventional treatment with manometry (97) pathway. Each patient in this study met at least 2 of the following criteria: less than 3 bowel movements per week, 2 or more soiling and/or encopresis episodes per week, occasional passage of very large amounts of stool every 7 – 30 days, or palpable rectal / abdominal fecal masses.
For children that underwent manometry (2 sessions per week), child and parent could watch the tracing on the computer screen, but no explanation was provided until after the study was complete. Treatment success was defined as 3 or more bowel movements per week and less than 1 soiling/encopresis episode per weeks with no use of laxatives.
Out of the 212 children in the study, only a total of 6 patients showed no soiling / encopresis after treatment (4 patients from the conventional therapy group and 2 patients from the conventional therapy with manometry group).
A total of 76% of conventional therapy patients reported the periodic passage of large stools, while 65% of patients in the conventional therapy with manometry group had the same findings. For 26% of conventional therapy patients, a rectal scybalum was found during physical examination, with 30% of the manometry group showing the same results. The follow-up success rates were as follows:
- 6 weeks: 4% and 7% for conventional therapy and conventional therapy with manometry, respectively
- 26 weeks: 24% and 22% for conventional therapy and conventional therapy with manometry, respectively
- 52 weeks: 32% and 30% for conventional therapy and conventional therapy with manometry, respectively
- 104 weeks: 43% and 35% for conventional therapy and conventional therapy with manometry, respectively
Overall, there was no significant difference in the success rate observed between the two groups. In both instances, a significant increase in defecation frequency was observed following treatment. Among the conventional therapy with manometry group, 28% of patients had normal defecation dynamics at the beginning of the study, compared to 38% of patients at the study’s conclusion.
Ultimately, while ARM is useful for a number of care paths, the results from this study suggest that anorectal manometry does not have an additional educational effect on the clinical outcome of children that are chronically constipated.
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- Buser WD, Miner PB. Delayed rectal sensation with fecal incontinence. Successful treatment using anorectal manometry. Gastroenterology. 1986;91(5):1186-91. Link
- Solomon MJ, Pager CK, Rex J, Roberts R, Manning J. Randomized, controlled trial of biofeedback with anal manometry, transanal ultrasound, or pelvic floor retraining with digital guidance alone in the treatment of mild to moderate fecal incontinence. Dis Colon Rectum. 2003;46(6):703-10. Link
- Heah SM, Ho YH, Tan M, Leong AF. Biofeedback is effective treatment for levator ani syndrome. Dis Colon Rectum. 1997;40(2):187-9. Link
- Ger GC, Wexner SD, Jorge JM, Salanga VD. Anorectal manometry in the diagnosis of paradoxical puborectalis syndrome. Dis Colon Rectum. 1993;36(9):816-25. Link
- Glia A, Gylin M, Gullberg K, Lindberg G. Biofeedback retraining in patients with functional constipation and paradoxical puborectalis contraction: comparison of anal manometry and sphincter electromyography for feedback. Dis Colon Rectum. 1997;40(8):889-95. Link
- Wald A. Use of biofeedback in treatment of fecal incontinence in patients with meningomyelocele. Pediatrics. 1981;68(1):45-9. Link
- Heymen S, Scarlett Y, Jones K, Ringel Y, Drossman D, Whitehead WE. Randomized, controlled trial shows biofeedback to be superior to alternative treatments for patients with pelvic floor dyssynergia-type constipation. Dis Colon Rectum. 2007;50(4):428-41. Link
- Van ginkel R, Büller HA, Boeckxstaens GE, Van der plas RN, Taminiau JA, Benninga MA. The effect of anorectal manometry on the outcome of treatment in severe childhood constipation: a randomized, controlled trial. Pediatrics. 2001;108(1):E9. Link