Translumbar and transsacral magnetic neurostimulation for the assessment of neuropathy in fecal incontinence.

BACKGROUND: Neurologic dysfunction causes fecal incontinence, but current techniques for its assessment are limited and controversial. OBJECTIVE: The purpose of this work was to investigate spino-rectal and spino-anal motor-evoked potentials simultaneously using lumbar and sacral magnetic stimulation in subjects with fecal incontinence and healthy subjects and to compare motor-evoked potentials and pudendal nerve terminal motor latency in subjects with fecal incontinence. DESIGN: This was a prospective, observational study. SETTINGS: The study took place in 2 tertiary care centers. PATIENTS: Subjects included adults with fecal incontinence and healthy subjects. INTERVENTIONS: Translumbar and transsacral magnetic stimulations were performed bilaterally by applying a magnetic coil to the lumbar and sacral regions in 50 subjects with fecal incontinence (1 or more episodes per week) and 20 healthy subjects. Both motor-evoked potentials and pudendal nerve terminal motor latency were assessed in 30 subjects with fecal incontinence. Stimulation-induced, motor-evoked potentials were recorded simultaneously from the rectum and anus with 2 pairs of bipolar ring electrodes. MAIN OUTCOME MEASURES: Latency and amplitude of motor-evoked potentials after lumbosacral magnetic stimulation and agreement with pudendal nerve terminal motor latency were measured. RESULTS: When compared with control subjects, 1 or more lumbo-anal, lumbo-rectal, sacro-anal, or sacro-rectal motor-evoked potentials were significantly prolonged (p < 0.01) and were abnormal in 44 (88%) of 50 subjects with fecal incontinence. Positive agreement between abnormal motor-evoked potentials and pudendal nerve terminal motor latency was 63%, whereas negative agreement was 13%. Motor-evoked potentials were abnormal in more (p < 0.05) subjects with fecal incontinence than pudendal nerve terminal motor latency, in 26 (87%) of 30 versus 19 (63%) of 30, and in 24% of subjects with normal pudendal nerve terminal motor latency. There were no adverse events. LIMITATIONS: Anal EMG was not performed. CONCLUSIONS: Translumbar and transsacral magnetic stimulation-induced, motor-evoked potentials provide objective evidence for rectal or anal neuropathy in subjects with fecal incontinence and could be useful. The test was superior to pudendal nerve terminal motor latency and appears to be safe and well tolerated.

Investigation of anal motor characteristics of the sensorimotor response (SMR) using 3-D anorectal pressure topography.

Desire to defecate is associated with a unique anal contractile response, the sensorimotor response (SMR). However, the precise muscle(s) involved is not known. We aimed to examine the role of external and internal anal sphincter and the puborectalis muscle in the genesis of SMR. Anorectal 3-D pressure topography was performed in 10 healthy subjects during graded rectal balloon distention using a novel high-definition manometry system consisting of a probe with 256 pressure sensors arranged circumferentially. The anal pressure changes before, during, and after the onset of SMR were measured at every millimeter along the length of anal canal and in 3-D by dividing the anal canal into 4 × 2.1-mm grids. Pressures were assessed in the longitudinal and anterior-posterior axis. Anal ultrasound was performed to assess puborectalis morphology. 3-D topography demonstrated that rectal distention produced an SMR coinciding with desire to defecate and predominantly induced by contraction of puborectalis. Anal ultrasound showed that the puborectalis was located at mean distance of 3.5 cm from anal verge, which corresponded with peak pressure difference between the anterior and posterior vectors observed at 3.4 cm with 3-D topography (r = 0.77). The highest absolute and percentage increases in pressure during SMR were seen in the superior-posterior portion of anal canal, reaffirming the role of puborectalis. The SMR anal pressure profile showed a peak pressure at 1.6 cm from anal verge in the anterior and posterior vectors and distinct increase in pressure only posteriorly at 3.2 cm corresponding to puborectalis. We concluded that SMR is primarily induced by the activation and contraction of the puborectalis muscle in response to a sensation of a desire to defecate.

Translumbar and transsacral motor-evoked potentials: a novel test for spino-anorectal neuropathy in spinal cord injury.

OBJECTIVES: Spinal cord injury (SCI) causes anorectal problems, whose pathophysiology remains poorly characterized. A comprehensive method of evaluating spino-anorectal function is lacking. The aim of this study was to investigate the neuropathophysiology of bowel dysfunction in SCI by evaluating motor-evoked potentials (MEP) of anus and rectum following transspinal magnetic stimulation and anorectal physiology. METHODS: Translumbar and transsacral magnetic stimulations, anorectal manometry, and pudendal nerve terminal motor latency (PNTML) were performed in 39 subjects with SCI and anorectal problems and in 14 healthy controls, and data were compared. MEPs were recorded with an anorectal probe containing bipolar ring electrodes. RESULTS: The MEPs were significantly prolonged (P<0.05) bilaterally, and at lumbar and sacral levels, as well as at rectal and anal sites in SCI subjects compared with controls. A total of 95% of SCI subjects had abnormal MEPs and 53% had abnormal PNTML. All subjects with abnormal PNTML also demonstrated abnormal MEP, but 16/17 subjects with normal PNTML had abnormal MEP. Overall, SCI patients had weaker anal sphincters (P<0.05), higher prevalence of dyssynergia (85%), and altered rectal sensation (82%). CONCLUSIONS: Translumbar and transsacral MEPs revealed significant and hitherto undetected lumbosacral neuropathy in 90% of SCI subjects. Test was safe and provided neuropathophysiological information that could explain bowel dysfunction in SCI subjects.

Diagnostic utility of wireless motility capsule in gastrointestinal dysmotility.

GOALS: To examine the diagnostic utility of wireless motility capsule (WMC) in patients with suspected gastrointestinal (GI) dysmotility. BACKGROUND: Subjects with suspected GI motility disorders undergo invasive and expensive diagnostic tests. In these patients, whether WMC provides clinically useful information is unknown. STUDY: Patients with symptoms of dysmotility and normal endoscopic/radiologic evaluations were assessed with WMC test and conventional motility tests (CMT). Diagnostic utility of WMC was assessed retrospectively by examining device agreement and new information compared with CMT. RESULTS: On the basis of predominant symptom(s), 86 patients were classified into 2 subgroups: lower GI (LGI=50) and upper GI (UGI=36). Clinical suspicion was confirmed in 52% and 66% of patients, respectively, and there was good device agreement between WMC and CMT in 76% and 81% in the LGI and UGI groups, respectively. There was new diagnostic information with the WMC test in 53% of the LGI (P=0.006) and 47% of the UGI group (P=0.001). WMC detected generalized motility disorder in 44 (51%) patients and influenced management in 30% of LGI and 50% of UGI subjects. CONCLUSIONS: WMC confirmed clinical suspicion, provided new diagnostic information, influenced clinical management, and detected many patients with generalized motility disorder. It had good device agreement with conventional tests.

Digital rectal examination is a useful tool for identifying patients with dyssynergia.

BACKGROUND & AIMS: Dyssynergic defecation is a common cause of chronic constipation; its diagnosis requires anorectal physiological tests that are not widely available. It is not known whether digital rectal examination (DRE) can be used to identify dyssynergia. We examined the diagnostic yield of DRE in patients with dyssynergic defecation. METHODS: Consecutive patients with chronic constipation (Rome III criteria, n = 209) underwent DREs, anorectal manometry analyses, balloon expulsion tests, and colonic transit studies. In the DRE, dyssynergia was identified by 2 or more of the following features: impaired perineal descent, paradoxic anal contraction, or impaired push effort; diagnostic yields were compared with physiological test results. RESULTS: Of the patients included in the study, 187 (87%) had dyssynergic defecation, based on standard criteria; 134 (73%) of these were identified to have features of dyssynergia, based on DREs. The sensitivity and specificity of DRE for identifying dyssynergia in patients with chronic constipation were 75% and 87%, respectively; the positive predictive value was 97%. DRE was able to identify normal resting and normal squeeze pressure in 86% and 82% of dyssynergic patients, respectively. CONCLUSIONS: DRE appears to be a reliable tool for identifying dyssynergia in patients with chronic constipation and detecting normal, but not abnormal, sphincter tone. DREs could facilitate the selection of appropriate patients for further physiologic testing and treatment.

Methanogenic flora is associated with altered colonic transit but not stool characteristics in constipation without IBS.

OBJECTIVES: About 35% of humans have methane-producing gut flora. Methane-producing irritable bowel syndrome (IBS) subjects are generally constipated. In animal models, methane infusion slows intestinal transit. Whether methanogenic flora alters colonic transit or stool characteristics and its relationship to constipation is unclear. The aim of this study was to examine the prevalence and association of methanogenic flora in patients with slow transit (ST) constipation and normal transit (NT) constipation and non-constipated controls. METHODS: Ninety-six consecutive subjects with chronic constipation (CC) (Rome III) were evaluated with radio-opaque marker (ROM) transit studies and were classified as ST (>20% ROM retention) or NT. All constipated subjects and 106 non-constipated controls underwent breath tests to assess methane production. Baseline CH4 of >or=3 p.p.m. was used to define presence of methanogenic flora. Stool frequency and consistency were assessed using a prospective stool diary. Correlation analyses were performed. RESULTS: Forty-eight subjects had ST and 48 had NT. Prevalence of methanogenic flora was higher (P<0.05) in ST (75%) compared to NT (44%) or controls (28%). ST patients had higher methane production compared to NT and controls (P<0.05). NT patients also produced more methane compared to controls (P<0.05). There was moderate(P<0.05) correlation among baseline, peak, and area under the curve (AUC) of methane response with colonic transit but not with stool characteristics. CONCLUSIONS: Presence of methanogenic flora is associated with CC. Methane production after carbohydrate challenge and its prevalence were higher in ST than NT, although stool characteristics were similar in both groups. Methane production correlated with colonic transit, suggesting an association with stool transport but not with stool characteristics.

Ability of the normal human small intestine to absorb fructose: evaluation by breath testing.

BACKGROUND & AIMS: Fructose consumption is increasing, and its malabsorption causes common gastrointestinal symptoms. Because its absorption capacity is poorly understood, there is no standard method of assessing fructose absorption. We performed a dose-response study of fructose absorption in healthy subjects to develop a breath test to distinguish normal from abnormal fructose absorption capacity. METHODS: In a double-blind study, 20 healthy subjects received 10% solutions of 15, 25, and 50 g of fructose and 33% solution of 50-g fructose on 4 separate days at weekly intervals. Breath samples were assessed for hydrogen (H2) and methane (CH4) during a period of 5 hours, and symptoms were recorded. RESULTS: No subject tested positive with 15 g. Two (10%) tested positive with 25 g fructose but were asymptomatic. Sixteen (80%) tested positive with 50 g (10% solution), and 11 (55%) had symptoms. Breath H2 was elevated in 13 (65%), CH4 in 1 (5%), and both in 2 (10%). Twelve (60%) tested positive with 50 g (33% solution), and 9 (45%) experienced symptoms. The area under the curve for H2 and CH4 was higher (P < .01) with 50 g compared with lower doses. There were no gender differences. CONCLUSIONS: Healthy subjects have the capacity to absorb up to 25 g fructose, whereas many exhibit malabsorption and intolerance with 50 g fructose. Hence, we recommend 25 g as the dose for testing subjects with suspected fructose malabsorption. Breath samples measured for H2 and CH4 concentration at 30-minute intervals and for 3 hours will detect most subjects with fructose malabsorption.

Email teleconsultations: well formulated clinical referrals reduce the need for clinic consultation.

We examined how well primary-care physicians formulated their clinical referrals when asking for help with patient-related clinical problems using an email-based teleconsultation service. Over 100 family physicians made use of the service. The specialists were medical school faculty members. The service was initiated in May 1996 with 19 specialists and expanded to 34 specialties over the next five years. A total of 1618 patient-related clinical questions were analysed, the outcome for the analysis being whether specialists recommended a clinic consultation. Specialists recommended a clinic consultation in response to 10% of their clinical questions about patients. There was a strong association between how family physicians formulated their clinical questions and whether the specialist recommended a clinic consultation. When the family physicians specified a clinical task (P < 0.001), intervention (P = 0.004) and outcome (P < 0.001) in their questions, specialists were less likely to recommend a clinic consultation. This influence was independent of the amount of clinical information included with the question (P > 0.05). About 5% of the questions that included all three question components resulted in the recommendation for a clinic consultation, compared with nearly 30% of the questions containing none of these components. How family physicians formulate their clinical questions influences whether specialists request a clinic consultation.

Effects of tegaserod and erythromycin in upper gut dysmotility: a comparative study.

OBJECTIVES: Tegaserod may enhance upper gut transit, but, its prokinetic effects on antral/small bowel motility and how this compares with erythromycin is unknown. We prospectively assessed and compared the effects of tegaserod and erythromycin on upper gut motility. METHODS: In an open label, non-crossover study, 22 patients (M/F=4/18; mean age=37 years) with symptoms of upper gut dysmotility underwent 24-hour ambulatory antroduodenojejunal manometry with a six-sensor solid state probe. The effects of 12 mg oral tegaserod were compared with 125 mg intravenous erythromycin by quantifying pressure wave activity and assessing motor patterns. RESULTS: Motor activity increased (p<0.05) in antrum, duodenum and jejunum with both drugs when compared to baseline period. The motor response with tegaserod was higher (p<0.05) in jejunum and occurred during the second or third hours, whereas with erythromycin, it was higher (p<0.05) in antrum and occurred within 30 minutes. After tegaserod, a 'fed-response' like pattern was seen whereas after erythromycin, large amplitude (>100 mmHg) antral contractions at 3 cycles per minute were seen. Following tegaserod and erythromycin, phase III MMCs occurred in 12 (55%) and 8 (36%) patients respectively (p>0.05). CONCLUSIONS: Both drugs increase upper gut motility and induce MMC's, but exert a differential response. Tegaserod produces a more sustained prokinetic effect in the duodenum/jejunum, whereas erythromycin predominantly increases antral motor activity.