Bowel Management in Spinal Cord Injury

Original Editor - Naomi O'Reilly

Top Contributors - Redisha Jakibanjar, Naomi O'Reilly, Kim Jackson, Anas Mohamed, Arnold Fredrick D'Souza, Admin and Lucinda hampton  

This article or area is currently under construction and may only be partially complete. Please come back soon to see the finished work! (21/06/2020)

Introduction

Neurogenic bowel dysfunction is characterized by alteration in normal bowel function due to the lack of nervous control. The clinical symptoms of neurogenic bowel may vary. Some clinical symptoms are bloating, constipation, abdominal pain, incontinence.

The symptoms of neurogenic bladder in Spinal Cord Injury(SCI) can be broadly divided into two headings:

• Upper Motor Neuron (UMN) bowel syndrome
• Lower Motor Neuron (LMN) bowel syndrome

Upper Motor Neuron (UMN) Bowel Syndrome, occurring in a spinal cord injury above the conus medullaris results in a hyperreflexic bowel, characterized by an increased colonic wall and anal tones, with disrupted voluntary external anal sphincter(EAS) control. The nerve connections between the spinal cord and colon remain intact so, sphincter remains tight, thereby promoting retention of stool and there is preserved reflex coordination and stool propulsion. Hence, UMN Bowel Syndrome is associated with constipation and fecal retention at least in part due to external anal sphincter activity.

Lower Motor Neuron (LMN) Bowel Syndrome, occurring in a spinal cord injury at the conus medullaris or cauda equina results in an areflexic bowel, characterized by loss of spinal cord-mediated peristalsis and slow stool propulsion with an atonic external anal sphincter. Typically associated with constipation and a significant risk of incontinence due to flaccid paralysis of the external anal sphincter and reduced motor control of levator ani.

The three main implications of disruption to the motor, sensory, and autonomic pathways post spinal cord injury on bowel function are an inability to:

1. feel when the bowel is full
2. voluntarily control muscles to defecate
3. voluntarily contract muscles to prevent defecating

Neurogenic bowel dysfunction can have different neuropathological patterns in people with SCI. They are:

• Pattern A: This pattern is seen in patients with SCI level above T7 and is characterized by loss of voluntary abdominal muscle contraction but preserved sacral spinal reflexes. Patients with this pattern have a moderate delay in Colonic transit time (CTT), absence of anal relaxation during the defecatory maneuver, and decreased intraabdominal pressure which causes very frequent constipation with significant defecatory difficulty and infrequent incontinence.
• Pattern B: Patients with SCI below T7 and who have preserved both voluntary control of abdominal muscles and preserved sacral reflexes fall under this pattern. Patients with pattern B have a moderate delay in CTT, have increased intra-abdominal pressure and increased anal resistance during the defecatory maneuver, presence of external anal sphincter contraction when intraabdominal pressure increases, and during rectal distension. So, they have frequent constipation, significant defecatory difficulty ad not very frequent incontinence.
• Pattern C: Patients with SCI·below T7 and who have voluntary control of abdominal muscles and absent sacral reflexes belong to this pattern. They have frequent constipation, less difficulty during defecation, and have a high chance of incontinence due to severe delay in CTT, increased intraabdominal pressure, absence of anal resistance during the defecatory maneuver, and absence of EAS contraction when intraabdominal pressure increases and during renal distension.

Consequences of Neurogenic Bowel Dysfunction(NBD)

People with NBD commonly have the following consequences in life:

• Loss of independence
• Feeling of embarrassment
• Social isolation (restrictions in social life)
• Decreased quality of life

Management of NBD

Bowel management will be successful only when the assessment is properly done, diagnosis is accurate and the treatment is individualized. The history-taking should include:

• Previous bowel and bladder habits and the findings should be related to current situations
• Premorbid bowel history which includes daily fluid intake, diet (fiber, meal frequency, spice preferences, amounts), bowel movements (frequency, duration, difficulties), stool (consistency, color, mucus, blood), medications.
• Examiner should be aware of the current Injury level, how much fluid does the patient take, what diet and medication dees the patient take, patient's understanding of the effect of spinal cord injury on elimination, bowel care habits (frequency, duration, digital stimulation, frequency/technique), bowel incontinence history (time of day, frequency, relationship to eating) of the patients
• before setting the intervention goals, the examiner should have knowledge about the lifestyle of the patient. Should have detailed knowledge about the schedules for work and school, availability of assistance if needed, amount of time needed to complete bowel care regimen.

Proper examination of the body and organs also gives a brief idea for the diagnosis of the patient. The bowel sounds should be auscultated and the abdomen should be properly palpated and check for distention.

Rectal examination should also be performed as it gives the idea about sphincter innervation and the amount and consistency of stool present in the rectal vault, the presence of hemorrhoids or masses, and in males the size of the prostate gland. Rectal examination should also determine the rectal angle and tone or spasticity of the puborectalis muscle. When the examining finger is inserted, it should be directed towards the umbilicus to check the rectal angle, and to check for puborectalis tone, gentle pressure is applied towards the sacrum. The strength and endurance of the voluntary muscles (EAS, puborectalis, and bulbocavernosus) should also be assessed.These findings will also help to differentiate whether the injury is UMN or LMN type.

The neurological examination should also include sacral reflexes, including anal tone, anocutaneous reflex (a contraction of the EAS in response to pricking or stroking the anal skin and it should be assessed in all four quadrants that surround the anal verge), bulbocavernosus reflex(pricking or pinching the dorsal glans penis or pressing the clitoris and palpating for bulbocavernosus and EAS contraction), and the internal anal sphincter reflexes(a contraction of the IAS with the stimulation of digital introduction to the rectum beyond the EAS and the sphincter is closed immediately on withdrawal).

Other examination methods include lab tests, radiographic findings, and liver function tests.

There are various management options available according to the condition of the patient. It can be pharmacological and Non-pharmacological(including surgery and conservative management).

Non-Pharmacological management

This method of management includes multifaceted programs, use of suppositories, dietary fibre, reflex Stimulation of the GI tract, abdominal massage, assistive devices, irrigation techniques, functional electrical and magnetic stimulation of skeletal muscles.

Multifaceted programs (level-4 evidence)

This technique includes targeting more than one factor for the goal of reducing the CTT and decreasing the incidence of difficult evacuations. There are various factors responsible for effective bowel management like diet modification, routine bowel evacuation, and anal stimulation.

Use of suppositories and oral laxatives (level-1 evidence)

The use of suppositories and oral laxatives is also another method commonly used. Bisacodyl and glycerin are used commonly as active ingredients in the suppositories.The oral laxatives include peristaltic stimulants, osmotic laxatives, bulk-forming agents, and stool softeners.

Dietary fibre (level-4 evidence)

Consuming fibre-rich diet has also shown benefit to some patients. But the result may vary from person to person so, care should be taken and only fibre rich diet might not be helpful all the time.

Reflex stimulation of the GI tract (level-4 evidence)

Digital rectal stimulation is presumed to increase the motility in the left colon by activating preserved anorectal colonic reflexes. Enemas can also be a vital technique for the facilitation of bowel evacuation.

Abdominal massage (level-4 evidence)

15 minutes of abdominal massage done for 15 days from cecum-colon-rectum has shown effective results for shortening the colonic transit time, decrease abdominal distension and increased frequency of bowel movements per week.

Assistive devices (level-4 and 5 evidence)

Various assistive devices can be used for effective bowel evacuation for instance modified toilet seat, standing table, washing toilet seat with a visual feedback system.

Irrigation techniques (level-4 and 5 evidence)

Transanal irrigation means inserting a balloon catheter into the rectum and slowly administering warm tap water in the specified volume. This technique has shown to improve constipation, fecal incontinence, and improve QoL. Enema continence catheter can also be used as an effective method for bowel evacuation.

Electric stimulation techniques

Electric stimulators are based on a mechanism to promote the normal function of the intestine through improving blood flow, promoting protein synthesis, reinforcing muscular strength, and regulating nerve stimulation. There are various kinds of electric stimulators used. Some are:

• Transcutaneous electrical stimulation- safe, noninvasive, painless and could stimulate sympathetic and parasympathetic nerve fibers in the bowel system and reduces the pressure of the internal and external sphincter in the anus. (level-1 evidence)
• Transrectal bowel stimulation- improves the ability to control the intestinal tract, enhances the sense of the need to defecate, and reduces intestinal peristalsis hence it reduces the rate of fecal incontinence
• Intravesical electrical stimulation- it decreases intravesical pressure and increases urinary bladder capacity and can also facilitate bladder emptying
• Sacral nerve stimulation- a relatively safe and effective method despite the minimally invasive procedure (level-4 evidence)
• Dorsal genital nerve electrical stimulation
• Percutaneous tibial nerve stimulation (level-4 evidence)
• Threshold night-time electrical stimulation

Colostomy(level 4 and 5 evidence)

A colostomy is a surgical process of connecting the colon to an opening in the abdominal wall making an artificial anus. This process is done to patients who have faced failure in all the medical treatments available for bowel management. It has shown to reduces the number of hospitalizations caused by gastrointestinal problems and improves physical health, psychosocial adjustment, and self-efficacy areas within the quality of life.

The Malone Antegrade Continence Enema and the Enema Continence Catheter (level-4 evidence)

This approach is creating an entry into large intestine surgically to irrigate the intestine. The procedure connects the appendix to the abdominal wall and acts as a valve mechanism that allows catheterization of the appendix, but avoids leakage of stool through it, thus forming an appendicostomy. Hence, a catheter can be introduced to the patient through the stoma and an enema can be administered. This process creates a washout effect and stimulates colonic peristaltic, the colon and rectum will empty, thus preventing fecal incontinence and constipation.

Pharmacological agents

Pharmacological drugs that can be used are :

• Cisapride(level 1 and 2 evidence)
• Prucalopride(level 1 evidence)
• Intravenous administration of metoclopramide(level 2 evidence)
• Neostigmine (a reversible cholinesterase inhibitor) or the combination of neostigmine and glycopyrrolate(level 1 evidence)
• Fampridine (selective potassium channel blocker) (level 1 evidence)

The table below shows the considerations and some management options.

Bowel Management Options	Considerations for Appropriate Bowel Management Options
High Fibre Diet	Presence or Absence of Bowel Reflexes Complete Lesions below the conus medullaris have loss of bowel reflexes, Complete Lesions above the conus medullaris do not have loss of bowel reflexes Hand Function Patients’ Preference Other Complex Factors
Adequate Fluid Intake
Regular Bowel Emptying Routine
Digital Stimulation Bowel Reflexes
Medication Oral e.g. Bowel Softeners Rectal e.g. Enemas