Pelvic Floor Nonrelaxation: Approach to Evaluation and Treatment

Abstract

Dyssynergic defecation can be a complex, burdensome condition. A multidisciplinary approach to these patients is often indicated based on concomitant pathology or symptomatology across the pelvic organs. Escalating treatment options should be based on shared decision making and include medical and lifestyle optimization, pelvic floor physical therapy with biofeedback, Botox injection, sacral neuromodulation, rectal irrigation, and surgical diversion.

Chronic constipation has a nearly 20% prevalence in the community, ¹ resulting in profound health care utilization, including rising costs from outpatient and inpatient care, diagnostic tests, and procedures. Additionally, there is a significant quality of life impact for each individual patient, including impaired work in up to 60% of patients. ² Therefore, accurate diagnosis and treatment are critical. The pivotal diagnostic hurdle is to differentiate functional (nonirritable bowel syndrome) chronic constipation as either slow transit constipation, outlet obstruction secondary to pelvic floor nonrelaxation, or a combination of these. Pelvic floor nonrelaxation has been known by many names in clinical practice and scientific literature, including anismus, dyssynergic defecation, obstructive defecation syndrome, outlet obstruction, and pelvic floor dyssynergia. Having standard definitions and precise language is important when communicating with both patients and other clinicians, ³ not just for the purposes of clinical diagnosis, but also to match appropriate treatments with patient symptoms and maintain a high quality of care delivery. Anismus refers to the paradoxic contraction of the external anal sphincter or puborectalis during an attempt at defecation. ^{3 4} Outlet obstruction and obstructed defecation syndrome refers to either functional or structural blockage to defecation and sensation of incomplete evacuation, which can be caused by anismus, rectal prolapse, or intussusception. ³ Dyssynergic defecation or pelvic floor dyssynergia encompasses any muscle dysfunction of the pelvic floor, absence of coordination between rectal pushing and anal canal relaxation, paradoxic anal contraction, or inadequate relaxation. ⁴ Herein we will use the term dyssynergic defecation when referring to pelvic floor nonrelaxation, and propose an algorithm to confirm the diagnosis and escalate treatment.

Confirming the Diagnosis

When dyssynergic defecation is suspected ( Fig. 1 ), a careful history and physical exam, as well as pelvic floor testing, will differentiate dyssynergic defecation from other disease processes. Difficulty evacuating can arise from other disease processes such as neoplasia, anal fissure, hemorrhoids, prolapse—including solitary rectal ulcer syndrome, proctitis, hypertensive sphincter, rectocele, or it can be self-induced due to straining.

Fig. 1.

Algorithm for evaluation and treatment of dyssynergic defecation.

Patients with dyssynergic defecation may describe incomplete evacuation, excessive straining, passage of hard stools, need for manual disimpaction or vaginal splinting, anorectal pain, tenesmus, and perineal heaviness or lumplike sensation. ⁴ A 2004 survey of 118 patients with dyssynergic defecation found that 76% of patients often or always experienced incomplete evacuation, 84% felt the need to strain excessively (21% of all patients had to strain for over 10 minutes), 74% felt abdominal fullness and bloating, and 18% often or always had to use their fingers to facilitate defecation (more common in women than men). ⁵ The same survey determined that 15% of patients believed their dyssynergic defecation was precipitated by illness, 9% by a surgery, and 5% of female respondents by childbirth. A history of physical abuse was reported by 29% of men and 32% of women and sexual abuse in 22% of participants, most of whom were women. When asked about the impact of their difficulties with defecation on quality of life, 74% reported that it affected their social life, 66% their work life, 64% their sexual life, and 39% their family relationships.

Accordingly, finding a way to standardize the reporting of symptoms and quantify the burden to an individual patient can be challenging. Simple measures such as number of bowel movements or stool caliber can be a good starting point, but may not be sufficient, as they vary between patients, and are not a reliable indicator of whether treatments are ultimately beneficial. Both symptom-specific and global patient reported symptom instruments exist in this regard, including the Cleveland Clinic Florida (CCF) constipation score and Patient Assessment of Constipation Quality of Life questionnaire. ^{6 7} Beyond the careful history, clinic visits should include a check for medication changes, surgical history, sexual trauma, and physical as well as a digital rectal exam. The examining practitioner should look and palpate for any masses or other anorectal pathology. Most importantly, during digital rectal exam, ask the patient to squeeze in order evaluate sphincter tone, and ask them to push to evaluate perineal descent, intussusception, and paradoxical tightening of the puborectalis muscle. Colonoscopy should always be part of this workup to rule out malignancy or other luminal disease. Also, patients should undergo comprehensive pelvic floor physiology testing that can include anorectal manometry (ARM), balloon expulsion, electromyography (EMG), and defecography.

ARM is performed by inserting a pressure sensing catheter into the distal rectum and measuring resting and squeeze pressures along the sphincter. The functional length of the anal canal can be measured and testing for the rectoanal inhibitory reflex (RAIR) can be performed. The presence of RAIR makes the diagnosis of Hirschprung's disease unlikely. Rao describes three types of dyssynergic defecation based on ARM during attempted defecation: (1) Rise in intrarectal pressure with paradoxic anal sphincter contraction, (2) no rise in rectal pressure with paradoxic sphincter contraction, and (3) adequate rise in intrarectal pressure with absent or incomplete sphincter relaxation. ⁴ There is also a fourth category with no increase in rectal pressure and no change in anal pressure. With a balloon on the ARM catheter, one can measure rectal sensation and capacity, and perform a simple evaluation of defecatory function. The balloon is inserted into the rectum with the ARM probe and filled with a standard amount of saline or the volume determined on manometric sensory testing to produce the urge to defecate. The patient is asked to expel the balloon in a seated position. The response is considered pathologic if the patient is unable to expel the balloon within 60 seconds. In a study of 130 patients with functional constipation, investigators determined that this test has a 97% negative predictive value excluding pelvic floor dysfunction and a positive predictive value of 64% in diagnosing pelvic floor dyssynergia (specificity 89%, sensitivity 87.5%). ⁸

EMG testing is performed by placing patches near the anal verge and measuring electrical activity with rest, squeeze, and push/simulated defecation. A normal response is a decrease in EMG activity with push, whereas patients with dyssynergic defecation will have an increase in EMG activity with push ( Fig. 2 ) or no change from resting activity with attempted push. EMG testing patches can also be used as part of biofeedback therapy to help patients to visualize whether their pelvic floor coordination is normal or paradoxic.

Fig. 2.

Electromyography (EMG) showing normal increase in signal with squeeze and decrease with push ( A ). EMG consistent with dyssynergia, increase in activity with push ( B ). Pink line is squeeze, yellow is rest, and green is push.

Defecography is a simple imaging test that allows for differentiation between outlet obstruction secondary to pelvic floor muscle dyssynergia versus internal pelvic organ prolapse. Defecography involves insertion of thickened contrast per rectum and vagina, and then the patient is asked to evacuate the rectal contrast, while fluoroscopic or magnetic resonance imagings are obtained. Ideally, patients are asked to evacuate the contrast while sitting on a radiolucent commode in the upright position. If the patient has pelvic floor dyssynergia, then defecography will demonstrate a failure of the anorectal angle to fully straighten with defecation suggesting nonrelaxation of the puborectalis ( Fig. 3 ). Additional findings that are consistent with pelvic floor dyssynergia may include incomplete evacuation of the contrast, prolonged evacuation time, or multiple strains/attempts to evacuate the loose contrast. Rectocele and internal intussusception are common findings on defecography for patients with dyssynergic defecation. However, these radiographic abnormalities exist with high prevalence in asymptomatic patients as well ⁹ and interpretation of whether these findings is truly due to dyssynergia as opposed to pelvic organ prolapse or simply normal evacuation should be made cautiously. Defecography will help to differentiate a rectocele or bulge into the posterior vagina that is secondary to a tight puborectalis muscle versus pelvic floor weakness and prolapse. This differentiation is crucial in providing the patient with an appropriate and successful treatment plan.

Fig. 3.

Defecography. ( A ) Normal rest, ( B ) normal push, ( C ) rest with dyssynergic defecation, ( D ) push with dyssynergic defecation; patient was unable to evacuate any contrast.

Escalating Management Options

While this review focuses specifically on the management of dyssynergic defecation, it is important to note that symptoms relating to dysfunction of the pelvic floor span the expertise of multiple clinical specialties and there is well-demonstrated “cross-talk” between the normal physiology (and pathophysiology) of the pelvic organs. ^{10 11} It is important to approach each patient in a multidisciplinary fashion to allow for individualized care: gastroenterologists to manage slow transit constipation, nutritionists to guide dietary modification, pain specialists to help with multimodal and alternative medications to treat pelvic and low back pain, psychiatrists to help with behavior modification, physical therapists for pelvic floor therapy and biofeedback, urogynecologists to address anterior, and middle compartment pathology. ¹²

Medical Management

Once a patient is diagnosed with dyssynergic defecation they should be counseled regarding appropriate bowel habits, stool softeners or fiber supplementation, and hydration. If there is a history of sexual abuse, psychiatric evaluation is recommended as the abuse experience has been linked to worse pain severity as well as interpersonal function. ¹³

Pelvic Floor Physical Therapy with Biofeedback

Biofeedback therapy is a critical component of treatment for dyssynergic defecation and will be discussed in a different chapter. Acupuncture and cognitive behavioral therapy can also be used as adjuncts for the treatment of pelvic pain. ¹⁴

Botulinum Toxin A

Botulinum toxin type-A (Botox) is a neurotoxin which blocks acetylcholine release from presynaptic nerve endings and causes muscle paralysis. When injected directly into the puborectalis, it can be used for the treatment of dyssynergic defecation ( Fig. 4 ). Injection can be done in the clinic, though we prefer the operating room to facilitate a full anoscopy and improved positioning for optimal exposure. The patient is positioned in lithotomy and sedation administered. A local anesthetic block in the pudendal nerve distribution is performed and a standard anorectal surgical instrument set is available to allow for a complete anoscopic evaluation. The posterior anorectal canal is exposed by retracting with an anoscope anteriorly, and the coccyx palpated. Botox 200 to 400 IU is reconstituted in 2 to 4 mL of normal saline and loaded in a 10mL syringe with a spinal length needle. The needle is used as a finder to confirm coccyx location. The needle is then partially withdrawn, angled laterally, and advanced into the puborectalis muscle (which feels “sticky” or “rubbery” when the needle is moved through it). A quarter (25%) of the Botox solution is injected in this location, immediately lateral to the coccyx. The needle is again partially removed and adjusted to a sharper angle in a slightly more lateral position and inserted into the puborectalis muscle where another 25% of the Botox solution is injected. The process is repeated on the contralateral side so that the entire Botox solution is injected. Hemostasis is confirmed and the procedure terminated.

Fig. 4.

Setup and technique for injection of Botox into puborectalis. A standard anorectal set is used to allow for full examination and anoscopy under sedation ( A ). Setup is prepared including local anesthetic of choice (short needle) and Botox injection (spinal needle) ( B ). Patient is positioned in lithotomy and local anesthetic is administered in perianal block to allow for a more comfortable anorectal exam under sedation ( C ). Using anoscopy to expose the anal canal, the tip of the coccyx is palpated ( D ). A spinal needle tip is used to feel the coccyx, and then moved laterally into the puborectalis, injecting Botox into both ( E ) right ( E ) and left sides of the muscle.

In a systematic review of two randomized controlled trials and five observational cohort studies, Emile et al provide insight into the efficacy of Botox for this indication. ¹⁵ They included 189 patients with symptoms of obstructed defecation, 53% of whom were female. The median dose of Botox used was 100 IU, which was injected either in lateral positions (five studies) or a combination of posterior and lateral (two studies). Initial clinical improvement was reported by a median of 77% (37.5–86.7%) patients, however, only by 46% (25–100%) at 4 months. Three observational studies employed two to three Botox injections and found this resulted in sustained improvement over the course of follow-up (6–39 months). ^{16 17 18} A patient's ability to expel the balloon after Botox was reported in a median of 75% of patients (38–80%). Complications occurred in 7.4% of patients with 5.8% reporting transient fecal incontinence. Emile et al concluded that Botox is associated with high short-term success, with longer term success associated with repeated injections. A second or third injection was not associated with any increase in complications, although the patient numbers in these studies were low (2–7 patients).

Zhang et al combined Botox injection with biofeedback therapy for 31 patients with anismus who had no improvement after an initial course of biofeedback. ¹⁹ After Botox injection and subsequent biofeedback 77% had an initial symptom improvement and 74% had a durable improvement over 8 months of follow-up. Combining Botox with pelvic floor therapy seems synergistic and thus it is beneficial to have patients continue therapy after Botox injection.

Rectal Irrigation

Bolstered by the success of colonic irrigation for colostomy patients and rectal irrigation for children with spina bifida in achieving defecatory control, transanal irrigation for dyssynergic defection exists as an additional therapy when other measures have failed. ²⁰ Although different commercial systems are available to facilitate irrigation (i.e., The Peristeen Anal Irrigation System, Coloplast ²¹ ), most function with a transanally introduced catheter, a tap water enema, and variable volumes, frequency, and duration. ²² In a systematic review of adult patients, including those with neurogenic bowel dysfunction, transanal irrigation improved symptoms of constipation in 45%, fecal incontinence in 47%, and mixed symptoms in 59%. ²² Symptom improvement in patients with obstructed defecation was found to be 57 to 65%. The risk of perforation associated with irrigation was 0.002%. If a given patient is having difficulty with their irrigation, the volume can be altered and oral laxative or constipating medications introduced. The authors argue that the benefit of transanal irrigation is more complete emptying of the left colon and rectum, allowing for predictability of defecation at minimal risk to the patient.

Sacral Neuromodulation

Sacral neuromodulation (SNM) is an established option for urinary and fecal incontinence and has been hypothesized to impact dyssynergic defecation through afferent and efferent neuronal function. ^{23 24} To date, the data to test this has been limited. Kamm et al evaluated 62 patients with slow transit constipation or normal transit with obstructed defecation, and found that at a median of 28 months there were statistically significant increases in frequency of defecation, decreased time straining, decreased perception of incomplete evacuation, and decreased CCF constipation scores. ²⁵ Knowles et al had just 13 patients but found normalization of rectal balloon distension volumes and a significant increase in percentage of successful bowel movements and CCF constipation scores at 19 months. ²⁶ Because these and other studies of SNM in “constipated” patients either do not specify the dyssynergic defecation subgroups, or are too small to meaningfully subtype these patients, these data should be extrapolated with caution.

Colostomy

Diversion has been traditionally reserved for refractory defecatory dysfunction. It is particularly important in patients with dyssynergic defecation to rule out slow transit constipation, which can co-exist in up to 50% of cases, ² and reach a shared decision with the patient about the goals of a surgical diversion in terms of symptom control and expectations. The impact on quality of life improvement after surgical diversion in patients with dyssynergic defecation has not been systematically evaluated.

Conclusion

Dyssynergic defecation can lead to high health care resource utilization and have a profound impact on a patient's quality of life. Using precise terminology and confirmatory diagnostic testing are important as there is overlap with other pathologies of the gastrointestinal tract or pelvic floor. These terms and instruments, as well as a multidisciplinary approach, are important in guiding a treatment plan that can be slowly and methodically escalated based on an individual patient's symptoms.