Anorectal function in patients with complete supraconal spinal cord lesions

Pelvic floor function in patients with clinically complete spinal cord injury and its relation to constipation

PURPOSE

Constipation is a common problem in patients with spinal cord injury. The aim of this study is to analyze the role of pelvic floor dysfunction in the development of constipation.

METHODS

Twenty-five patients with clinically complete supraconal spinal cord injury were studied by means of colonic transit time, anal manometry, electrophysiologic testing, and sensory-evoked potentials.

RESULTS

Sixteen patients had prolonged total and segmental colonic transit times (Group C), and nine patients had normal colonic transit times (Group NC). Basal pressure and anal pressure during coughing, Valsalva's maneuver, and rectal distention were diminished in all patients, but no differences were observed between Group C and Group NC. Rectal sensation was preserved in eight patients, but this was not related to the absence of constipation. In seven of these eight patients, somatosensory-evoked potentials could be recorded, which indicated an incomplete cord lesion. Synergic relaxation of the pelvic floor during straining was never observed; dyssynergia was seen in ten (7 in Group C and 3 in Group NC; P = not significant) patients. Associated peripheral nerve damage was present in 40 percent of patients but did not predispose these patients to constipation.

CONCLUSIONS

Loss of rectal sensation, dyssynergic pelvic floor contraction during straining, associated peripheral nerve damage, and insufficient rise of intraabdominal pressure could not be held responsible for constipation as a result of spinal cord injury. A prolongation of the colonic transit time is the most important mechanism, and therapy should be directed toward it.

External anal sphincter hyperreflexia following spinal transection in the rat

In the present study, long-term and short-term rat preparations were used to develop a model for investigating external anal sphincter (EAS) reflexes in intact and spinal cord-injured (SCI) rats. In this model, EAS distension with an external probe elicits reflex contractions of the EAS in intact, unanesthetized animals. At 2 h after spinal cord transection, none of the lesioned animals displayed EAS EMG activity. In fact, once distended, the EAS was incapable of maintaining closure of the anal orifice. Over a period of 4 days, spinalized animals developed a hyperreflexia of the EAS response. By 48 h, the rectified, integrated EAS EMG was significantly elevated in comparison with nonlesioned controls (EAS hyperreflexia). In addition, the duration of the EAS EMG bursts in response to sphincter distension had significantly increased. At 6 weeks after injury, the EAS was significantly hyperreflexic as measured by EMG burst duration and burst area. As with intact animals, posttransection EAS reflexes were highly anesthesia sensitive. These studies indicate that (1) brief distension of the anal orifice is sufficient to evoke a physiologically relevant reflexive activation of the EAS in the rat, (2) the 2- to 24-h postinjury areflexia observed in these experiments may be a suitable model for the study of spinal shock, and (3) the observed EAS hyperreflexia after chronic SCI may represent the permanent effects of removing descending inhibitory circuits and segmental plasticity, making this reflex an appropriate measure of defecatory dysfunction after spinal cord injury.

Neurogenic bowel dysfunction after spinal cord injury: clinical evaluation and rehabilitative management

Neurogenic bowel dysfunction (NBD) is one of many impairments that result from spinal cord injury (SCI). The experience of persons with SCI reveals that the risk and occurrence of fecal incontinence and difficulty with evacuation are particularly significant life-limiting problems. This review relates the anatomy and physiology of colon function to the specific pathophysiology that detracts from the quality of life of persons after SCI. There are two patterns of NBD after SCI: the upper motor neuron bowel, which results from a spinal cord lesion above the sacral level, and the lower motor neuron bowel, which results from a lesion to the sacral spinal cord, roots, or peripheral nerve innervation of the colon. Rehabilitation evaluation consists of a comprehensive history and examination to define impairments, disabilities, and handicaps pertinent to NBD. Rehabilitation goals include continence of stool, simple willful independent defecation, and prevention of gastrointestinal complications. Intervention consists of derivation and implementation of an individualized person-centered bowel program, which may include diet, oral/rectal medications, equipment, and scheduling of bowel care. Bowel care is a procedure devised to initiate defecation and accomplish fecal evacuation. Digital-rectal stimulation is a technique utilized during bowel care to open the anal sphincter and facilitate reflex peristalsis. Recent advances in rehabilitation practices, equipment, pharmacology, and surgery have offered patients new bowel program alternatives. Interdisciplinary development of solutions for problems of NBD are evolving rapidly.

A retrospective study of the effects of pelvic irradiation for gynecological cancer on anorectal function

PURPOSE

To evaluate the prevalence of anorectal dysfunction following therapeutic pelvic irradiation.

METHODS AND MATERIALS

Anorectal function was evaluated in 15 randomly selected patients (aged 47-84 years) who had received pelvic irradiation for treatment of carcinoma of the uterine body and cervix 5 and 10 years earlier. The following parameters were assessed in each patient: (a) anorectal symptoms (questionnaire), (b) anorectal pressures at rest and in response to rectal distension, voluntary squeeze, and increases in intraabdominal pressure (multiport anorectal manometry with concurrent electromyography of the anal sphincters), (c) rectal sensation (rectal balloon distension) and, (d) anal sphincteric morphology (ultrasound). Results were compared with those obtained in nine female control subjects.

RESULTS

Ten of the 15 patients had urgency of defecation and 4 also suffered fecal incontinence. Basal anorectal pressures measured just proximal to the anal canal (p = 0.05) and anorectal pressures generated in response to voluntary squeeze measured at the anal canal were less (p < 0.01) in the patients. The fall in anal pressures in response to rectal distension was greater in the patients (p < 0.05) and the desire to defecate occurred at lower rectal volumes (p < 0.05). The slope of the pressure/volume relationship in response to rectal distension was greater (p < 0.05) in the patients, suggestive of a reduction in rectal compliance. In 14 of the 15 patients at least one parameter of anorectal motor function was outside the control range. There was no difference in the thickness of the anal sphincters between the two groups.

CONCLUSION

Abnormal anorectal function occurs frequently following pelvic irradiation for gynecological malignant diseases and is characterized by multiple dysfunctions including weakness of the external anal sphincter, stiffness of the rectal wall, and a consequent increase in rectal sensitivity.

Role of segmental colonic transit time studies to select patients with slow transit constipation for partial left-sided or subtotal colectomy

This prospective study investigated the value of segmental colonic transit time studies in the surgical treatment of slow transit constipation. Overall, 346 patients with chronic constipation were analysed; slow transit constipation was diagnosed in 86 (25 per cent). Based on the results of segmental colonic transit time studies, 18 patients underwent partial left-sided colectomy and 24 subtotal colectomy. Recurrent constipation was seen in three of 18 patients and seven of 24 respectively. Severe abdominal discomfort was noted in six of 18 and 15 of 24 respectively. Disabling diarrhoea and faecal incontinence developed in two of 14 and five of 20 patients with an anastomosis respectively. Although these results indicate that segmental colonic transit time studies are useful in selecting patients with slow transit constipation for partial left-sided or subtotal colectomy, both procedures should be performed with prudence.

Evidence for the hypersensitivity of lumbar splanchnic afferents in irritable bowel syndrome

BACKGROUND/AIMS

The pathways underlying rectal hypersensitivity to balloon distention in patients with irritable bowel syndrome (IBS) are not known. The aim of this study was to characterize the involvement of sacral and thoracolumbar afferents in the perception of rectal distention.

METHODS

Rectal balloon distention was performed in 15 normal control subjects, 6 patients with spinal cord injury, and 50 patients with IBS using a slow-volume ramp (40 mL/min) or rapid phasic step distension. Additional studies were performed in the presence of 2% intrarectal lidocaine.

RESULTS

Patients with spinal cord injury with lesions below T7 reported sensations only during phasic distention. Sixty percent of patients with IBS (n = 50) were hypersensitive for discomfort during phasic distention, whereas only 4% were hypersensitive during ramp distention. Less than 15% of patients were hypersensitive for the sensation of stool. In normal patients, lidocaine increased thresholds in response to slow ramp distention by 40%-70% but had no effect on perception in response to other types of distention. Lidocaine had no effect on (1) thresholds in response to either ramp or phasic distention in normosensitive or hypersensitive patients with IBS or (2) the rate of receptive relaxation or rectal compliance in any group.

CONCLUSIONS

Rapid phasic distention preferentially stimulates splanchnic afferents. Hypersensitivity of these afferents in patients with IBS is unaffected by mucosally applied lidocaine.

The cough response of the anal sphincter

Rises in intra-abdominal pressure are common and are accompanied by reflex contraction of the external sphincter. Voluntary contraction of the sphincter is an uncommon event but is routinely used as a measure of sphincter strength. Cough pressure and squeeze pressure were compared in 75 patients using a 4 channel perfused catheter (3 anal and 1 rectal side-hole). Maximum anal cough pressure was higher than squeeze pressure (mean 158 vs 133 cm H2O, P = 0.0015). Intra-individual variance was less using cough pressure (mean 20% vs 29%, P = 0.005). There was significant overall correlation between cough pressure and squeeze pressure (P < 0.001) although in some cases there were wide differences, suggesting that use of both cough and squeeze pressure in manometry will assess sphincter strength more reliably. Measurement of the recto-anal pressure gradient during coughing correlated significantly better with degree of incontinence than cough or squeeze pressure (P = 0.005). The presence of a positive gradient was 100% specific for incontinence but the sensitivity was only 43% suggesting that factors other than simple mechanical sphincter weakness are involved in incontinence. Measurement of cough pressure has both clinical and research importance and should be added to standard manometric protocols.