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ABSTRACT: Impaired or blunted rectal sensation, termed rectal hyposensitivity (RH), which is defined clinically as elevated sensory thresholds to rectal balloon distension, is associated with disorders of hindgut function, characterised primarily by symptoms of constipation and fecal incontinence. However, its role in symptom generation and the pathogenetic mechanisms underlying the sensory dysfunction remain incompletely understood, although there is evidence that RH may be due to 'primary' disruption of the afferent pathway, 'secondary' to abnormal rectal biomechanics, or to both. Nevertheless, correction of RH by various interventions (behavioural, neuromodulation, surgical) is associated with, and may be responsible for, symptomatic improvement. This review provides a contemporary overview of RH, focusing on diagnosis, clinical associations, pathophysiology, and treatment paradigms.
Journal of neurogastroenterology and motility 10/2012; 18(4):373-84.
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ABSTRACT: Prospective randomized double-blind placebo-controlled crossover trial of 14 female patients (median age 52 [30-69] years) with proctographically defined evacuatory dysfunction (ED) and demonstrable rectal hyposensitivity (elevated thresholds to balloon distension in comparison with age- and sex-matched controls).
Sacral nerve stimulation (SNS) is an evolving treatment for constipation. However, variable outcomes might be improved by better patient selection. Evidence that the effect of SNS may be mediated by modulation of afferent signaling promotes a role in patients with ED associated with rectal hyposensation.
SNS was performed by the standard 2-stage technique (temporary then permanent implantation). During a 4-week period of temporary stimulation, patients were randomized ON-OFF/OFF-ON for two 2-week periods. Before insertion (PRE), and during each crossover period, primary (rectal sensory thresholds) and secondary (bowel diaries, constipation, and GIQoL [gastrointestinal quality of life] scores) outcome variables were blindly assessed.
Thirteen patients completed the trial. Following stimulation, defecatory desire volumes to rectal balloon distension were normalized in 10 of 13 patients (PRE: mean 277 mL [234-320] vs ON: 163 mL [133-193] vs OFF: 220 mL [183-257 mL]; P = 0.006) and maximum tolerable volume in 9 of 13 (PRE: mean 350 mL [323-377] vs ON: 262 mL [219-305] vs OFF: 298 mL [256-340 mL]; P = 0.012). There was a significant increase in the percentage of successful bowel movements (PRE: median 43% [0-100] vs ON: 89% [11-100] vs OFF: 83% [11-100]; P = 0.007) and Wexner constipation scores improved (PRE: median 19 [9-26] vs ON: 10 [6-27] vs OFF: 13 [5-29]; P = 0.01). There were no significant changes in disease-specific or generic quality of life measures. Eleven patients progressed to permanent stimulation (9/11 success at 19 months).
Most patients with chronic constipation secondary to ED with rectal hyposensitivity responded to temporary SNS. The physiological results presented support a mechanistic role for rectal afferent modulation.
Annals of surgery 04/2012; 255(4):643-9. · 7.90 Impact Factor
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ABSTRACT: Human defecation involves integrated and coordinated sensorimotor functions, orchestrated by central, spinal, peripheral (somatic and visceral), and enteric neural activities, acting on a morphologically intact gastrointestinal tract (including the final common path, the pelvic floor, and anal sphincters). The multiple factors that ultimately result in defecation are best appreciated by describing four temporally and physiologically fairly distinct phases. This article details our current understanding of normal defecation, including recent advances, but importantly identifies those areas where knowledge or consensus is still lacking. Appreciation of normal physiology is central to directed treatment of constipation and also of fecal incontinence, which are prevalent in the general population and cause significant morbidity.
Digestive Diseases and Sciences 02/2012; 57(6):1445-64. · 2.12 Impact Factor
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ABSTRACT: The pathophysiology of fecal incontinence in men is poorly established.
The aim of this study was to assess the coexistence of constipation and determine the impact of rectal sensorimotor dysfunction in males with fecal incontinence.
This study was conducted at a tertiary referral center.
Included were adult male patients referred for the investigation of fecal incontinence over a 5-year period who underwent full anorectal physiology testing and completed a standardized symptom questionnaire.
Standardized symptom questionnaires were fully completed, and anorectal physiologic test results (including evacuation proctography) were evaluated.
: The primary outcomes measured were the frequency of symptoms of associated constipation, the association of blunted rectal sensation (rectal hyposensitivity) with symptoms, and other physiologic measures.
One hundred sixty patients met the inclusion criteria, and 47% of these patients described concurrent constipation. Fifty-four patients (34%) had sphincter dysfunction on manometry, only 19 of whom had structural abnormalities on ultrasound. Overall, 28 patients (18%) had rectal sensory dysfunction, 26 (93%) of whom had rectal hyposensitivity. Patients with rectal hyposensitivity were more likely to subjectively report constipation (77%) in comparison with patients with normal rectal sensation (44%; p = 0.001), allied with decreased bowel frequency (19% vs 2%; p = 0.003) and a sense of difficulty evacuating stool (27% vs 8%; p = 0.008). Cleveland Clinic constipation scores were higher in patients with rectal hyposensitivity (median score, 13 (interquartile range: 8-17) vs normosensate, 9 (5-13); p = 0.004). On proctography, a higher proportion of patients with rectal hyposensitivity had protracted defecation (>180 s; 35% vs 10%; p = 0.024) and incomplete rectal evacuation (<55% of barium neostool expelled, 50% vs 20%; p = 0.02).
: This study was limited by the retrospective analysis of prospectively collected data.
Only one-third of incontinent men had sphincteric dysfunction. Other pathophysiologies must therefore be considered. Nearly half of patients reported concurrent constipation, and one-sixth had rectal hyposensitivity, which was associated with higher frequencies of both symptomatic and objective measures of rectal evacuatory dysfunction. In the majority of adult males, fecal incontinence may represent a secondary phenomenon.
Diseases of the Colon & Rectum 01/2012; 55(1):18-25. · 3.13 Impact Factor
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Journal of pediatric gastroenterology and nutrition 12/2011; 53 Suppl 2:S47-9. · 2.18 Impact Factor
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Nature Reviews Gastroenterology & Hepatology 06/2011; 8(6):306-7. · 8.10 Impact Factor
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ABSTRACT: Stereotypical changes in pH occur along the gastrointestinal (GI) tract. Classically, there is an abrupt increase in pH on exit from the stomach, followed later by a sharp fall in pH, attributed to passage through the ileocecal region. However, the precise location of this latter pH change has never been conclusively substantiated. We aimed to determine the site of fall in pH using a dual-scintigraphic technique. On day 1, 13 healthy subjects underwent nasal intubation with a 3-m-long catheter, which was allowed to progress to the distal ileum. On day 2, subjects ingested a pH-sensitive wireless motility capsule labeled with 4 MBq (51)Chromium [EDTA]. The course of this, as it travelled through the GI tract, was assessed with a single-headed γ-camera using static and dynamic scans. Capsule progression was plotted relative to a background of 4 MBq ¹¹¹Indium [diethylenetriamine penta-acetic acid] administered through the catheter. Intraluminal pH, as recorded by the capsule, was monitored continuously, and position of the capsule relative to pH was established. A sharp fall in pH was recorded in all subjects; position of the capsule relative to this was accurately determined anatomically in 9/13 subjects. In these nine subjects, a pH drop of 1.5 ± 0.2 U, from 7.6 ± 0.05 to 6.1 ± 0.1 occurred a median of 7.5 min (1-16) after passage through the ileocecal valve; location was either in the cecum (n = 5), ascending colon (n = 2), or coincident with a move from the cecum to ascending colon (n = 2). This study provides conclusive evidence that the fall in pH seen within the ileocolonic region actually occurs in the proximal colon. This phenomenon can be used as a biomarker of transition between the small and large bowel and validates assessment of regional GI motility using capsule technology that incorporates pH measurement.
AJP Gastrointestinal and Liver Physiology 12/2010; 299(6):G1276-86. · 3.43 Impact Factor
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ABSTRACT: Colonic motility subserves large bowel functions, including absorption, storage, propulsion and defaecation. Colonic motor dysfunction remains the leading hypothesis to explain symptom generation in chronic constipation, a heterogeneous condition which is extremely prevalent in the general population, and has huge socioeconomic impact and individual suffering. Physiological testing plays a crucial role in patient management, as it is now accepted that symptom-based assessment, although important, is unsatisfactory as the sole means of directing therapy. Colonic manometry provides a direct method for studying motor activities of the large bowel, and this review provides a contemporary understanding of how this technique has enhanced our knowledge of normal colonic motor physiology, as well as helping to elucidate pathophysiological mechanisms underlying constipation. Methodological approaches, including available catheter types, placement technique and recording protocols, are covered, along with a detailed description of recorded colonic motor activities. This review also critically examines the role of colonic manometry in current clinical practice, and how manometric assessment may aid diagnosis, classification and guide therapeutic intervention in the constipated individual. Most importantly, this review considers both adult and paediatric patients. Limitations of the procedure and a look to the future are also addressed.
World Journal of Gastroenterology 11/2010; 16(41):5162-72. · 2.47 Impact Factor
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ABSTRACT: Sacral nerve stimulation has traditionally been used to treat patients with fecal incontinence with intact anal sphincters. This rationale has been challenged, but it remains unknown if its efficacy is related to the extent of the sphincter injury.
This was a prospective study of 15 patients with sphincter defects (9 combined, 2 external only, and 4 internal only) undergoing sacral nerve stimulation for fecal incontinence. Endoanal ultrasound scans were reviewed and defects scored (0-16) with use of a system published by two independent observers. These were correlated with the following outcomes: 1) reduction in fecal incontinence episodes, 2) reduction in soiling, 3) improvement in Cleveland Clinic scores, and 4) improvement in ability to defer defecation. All patients were studied after temporary stimulation and again at three to six months after permanent implantation.
Thirteen patients (87%) progressed to permanent stimulation. Median fecal incontinence episodes per two weeks decreased from 15 (range, 1-53) to 3 (range, 0-16; P = 0.01). Median soiling episodes were reduced from 10 (range, 1-14) to 6 (range, 0-14; P = 0.009). Median Cleveland Clinic scores decreased from 12 (range, 9-18) to 9 (range, 4-14; P = 0.0005). The ability to defer defecation was improved significantly (P = 0.05). There were no relationships between sphincter defect scores and outcome measures after sacral nerve stimulation (r = 0.001-0.10; P = 0.28-0.94).
Sacral nerve stimulation is an effective treatment in patients with fecal incontinence who have anal sphincter defects, and outcome is not associated with severity of sphincter disruption.
Diseases of the Colon & Rectum 08/2009; 52(7):1234-9. · 3.13 Impact Factor
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ABSTRACT: With advances in diagnostic technology, it is now accepted that in the field of functional bowel disorders, symptom-based assessment is unsatisfactory as the sole means of directing therapy. A robust taxonomy based on underlying pathophysiology has been suggested, highlighting a crucial role for physiologic testing in clinical practice. A wide number of complementary investigations currently exist for the assessment of anorectal structure and function, some of which have a clinical impact in patients with functional disorders of evacuation and continence by markedly improving diagnostic yield and altering management. The techniques, limitations, measurements, and clinical use of manometric, sensorimotor, and neurophysiologic tests of anorectal function are presented.
Gastroenterology Clinics of North America 10/2008; 37(3):511-38, vii. · 2.62 Impact Factor
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ABSTRACT: Rectal augmentation (RA) with or without electrically stimulated gracilis neosphincter (ESGN) was developed to address the physiologic and anatomic abnormalities present in a subset of patients with incapacitating fecal urgency and associated urge fecal incontinence (UFI). This study evaluated the short- and medium-term clinical and physiologic results.
Eleven patients with fecal urgency and UFI underwent RA, 6 with concomitant ESGN formation. Patients were evaluated preoperatively, and at a median of 12.5 and 54 months after surgery.
At 4.5 years, 7/11 patients had avoided stoma construction. Symptoms recurred leading to permanent stoma formation in 1 patient, whereas one other developed evacuatory difficulty with overflow incontinence. Median ability to defer defecation improved from seconds preoperatively to 10 minutes at 1 year (P = 0.0002), and 15 minutes at 4.5 years (P = 0.002). Median Wexner incontinence scores improved from 15 preoperatively to 3 at 1 year (P = 0.002), and 4 at 4.5 years (P = 0.02). At 1 year, 2 of the rectal sensory thresholds (DDV: P = 0.008; MTV: P = 0.008) and compliance were normalized (P = 0.008), whereas at 4.5 years, all sensation thresholds improved (FCS: P = 0.002; DDV: P = 0.002; MTV: P = 0.002), but changes in compliance were not significant.
RA with or without ESGN improved reported symptoms and normalized rectal sensation. Improvements were sustained in the medium term. The procedure had no associated morbidity or mortality, and should be considered in the surgical management of a select group of patients presenting with severe urgency and UFI.
Annals of Surgery 04/2008; 247(3):421-7. · 7.49 Impact Factor
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ABSTRACT: Severe constipation may be subclassified on the basis of speed of colonic transit and efficacy of rectal evacuation. It is hypothesized that rectal evacuatory disorder (RED) may be associated with a secondary transit delay.
To determine whether scintigraphy can discriminate between slow transit constipation (STC) with or without coexistent RED on the basis of progression of isotope throughout the colon and by analyses of specific regions of interest.
One hundred ninety-six patients with STC (radio-opaque marker study) were subclassified according to results of proctography into those with a RED (STC-RED N = 30) or normal (STC-ONLY N = 41) evacuation. Patients subsequently underwent colonic scintigraphy. Distribution of generalized or left-sided patterns of colonic transit was assessed. Severities of transit delay and regional transit at specific time points were also evaluated.
Time-activity curves and severity of global transit delay were similar between groups as were the incidences of generalized and left-sided patterns of delay. Percentage of radioisotope retention in the right colon at 18 h was higher for the STC-ONLY group (P < 0.05), but this was poorly discriminative. No differences were observed for the percentage of radioisotope retained in the left colon at later scans.
Global and regional assessment of colonic transit by scintigraphy failed to discriminate between patients with STC with or without coexistent RED. Thus, RED is not associated with a specific pattern of transit delay and scintigraphy alone cannot predict the presence or absence of RED, knowledge of which is important for management.
The American Journal of Gastroenterology 03/2008; 103(2):427-34. · 7.28 Impact Factor
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ABSTRACT: Traditional methods of identifying patients with persistent dilation of the rectum, or megarectum, are associated with inherent methodologic limitations. The purpose of this study was to use a barostat to establish criteria for the diagnosis of megarectum and to assess rectal diameter during isobaric (barostat) and volumetric (barium contrast) distention protocols in constipated patients with megarectum on anorectal manometry.
During fluoroscopic screening, rectal diameter was measured at minimum distending pressure of the rectum, achieved using a barostat. It was also measured during evacuation proctography (volumetric distention). Having established a normal range in 25 healthy volunteers, 30 constipated patients with evidence of megarectum on anorectal manometry (elevated maximum tolerable volume on latex balloon distention) were studied. A further 10 constipated patients without evidence of megarectum were studied (normal rectum).
Megarectum was diagnosed when the rectal diameter was greater than 6.3 cm at minimum distending pressure. Rectal diameter at minimum distending pressure was increased in 20 patients (67 percent) with megarectum on anorectal manometry, but was normal in the remaining 10 patients (33 percent) and all patients with a normal rectum on anorectal manometry. Rectal diameter was increased at evacuation proctography in only 15 patients (50 percent) with evidence of megarectum on anorectal manometry.
The prevalence of megarectum is overestimated and underestimated when rectal diameter is assessed using anorectal manometry and contrast studies, respectively. Controlled (pressure-based) distention combined with fluoroscopic imaging allowed accurate identification of patients with megarectum on the basis of a rectal diameter greater than 6.3 cm at the minimum distention pressure. Measurement of rectal diameter at minimum distention pressure may be useful in those patients with an elevated maximum tolerable volume on anorectal manometry when surgery is being contemplated.
Diseases of the Colon & Rectum 06/2007; 50(5):621-9. · 3.13 Impact Factor
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Journal of the American College of Surgeons 05/2007; 204(4):673-80. · 4.55 Impact Factor
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ABSTRACT: Pudendal neuropathy and fecal incontinence frequently coexist; however, the contribution of neuropathy is unknown. The pudendal nerve innervates the external anal sphincter muscle, anal canal skin, and coordinates reflex pathways. Lateral dominance or a dominantly innervating nerve and its subsequent damage may have major implications in the etiology and treatment of fecal incontinence. This study was designed to establish the prevalence of pudendal neuropathy, in particular a unilateral one, and to examine the impact on anorectal function.
A total of 923 patients (745 females; mean age, 52 (range, 17-92) years) with fecal incontinence were studied using endoanal ultrasonography, anorectal manometry, rectal sensation, and pudendal nerve terminal motor latencies.
A total of 520 patients (56 percent) demonstrated a pudendal neuropathy, which was unilateral in 38 percent (351 patients; 169 right-sided, 182 left-sided). Neuropathy, whether it was bilateral (bilateral vs. normal; 56 (range, 7-154) cm H2O) vs. 67 (range, 5-215) cm H2O; P < 0.01) or unilateral (unilateral vs. normal; 61 (range, 0-271) cm H2O vs. 67 (range, 5-215) cm H2O; P = 0.04) was associated with reduced anal resting tone. This also was seen with respect to squeeze increments (bilateral vs. normal; 34 (range, 0-207) cm H2O vs. 52 (range, 0-378) cm H2O; P < 0.001, unilateral vs. normal; 41 (range, 0-214) cm H2O vs. 52 (range, 0-378) cm H2O; P < 0.01). In those with intact sphincters, unilateral neuropathy was associated with reduced squeeze increments (unilateral vs. normal; 60 (range, 10-286) cm H2O vs. 69 (range, 7-323) cm H2O; P = 0.01) but no significant reduction in resting pressures. There was no association between pudendal neuropathy and abnormal rectal sensitivity.
Unilateral pudendal neuropathy is a common abnormality in individuals with fecal incontinence and is significantly associated with both attenuated resting pressures and squeeze increments. Although there are limitations in the interpretation of pudendal nerve terminal motor latencies, this study demonstrates that further exploration of the concept of lateral dominance is needed.
Diseases of the Colon & Rectum 05/2007; 50(4):449-58. · 3.13 Impact Factor
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03/2007: pages 102-122;
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03/2007: pages 89-101;
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ABSTRACT: Internal rectal prolapse has been proposed as a cause of symptomatic rectal evacuatory dysfunction. Abdominal rectopexy, the standard surgical approach, has significant attendant risk and does not address any concomitant rectocele. This video was designed to demonstrate a novel surgical method that uses porcine collagen implants (Permacol), designed to correct internal rectal prolapse, with or without rectocele.
Inclusion criteria: severe rectal evacuatory dysfunction refractory to maximal conservative therapy and full-thickness internal rectal prolapse impeding rectal emptying on defecography with or without associated functional rectocoele; normal colonic transit. Patients undergo comprehensive preoperative and postoperative symptomatic assessment and anorectal physiologic testing, including defecography. A crescenteric perineal skin incision allows development of the rectovaginal/rectoprostatic plane to Denonvilliers fascia, with rectal mobilization. A curved tunneller inserted via the perineal wound is guided retropubically to emerge through suprapubic wounds created on each side. Permacol T-strips are sutured to the anterolateral rectal wall bilaterally, upward traction exerted, and the stem of each T-strip is sutured to the suprapubic periosteum, suspending the rectum. Concomitant rectocele is repaired using a Permacol patch in the rectovaginal plane.
Short-term results for the "Express" are encouraging with improvement in evacuatory and prolapse symptoms and concomitant anatomic improvement at defecography.
This procedure promises to be an effective technique for managing patients with refractory evacuatory dysfunction secondary to internal rectal prolapse, with or without rectocele.
Diseases of the Colon & Rectum 01/2007; 49(12):1922-6. · 3.13 Impact Factor
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ABSTRACT: Webster’s dictionary defines continence as “the ability to retain a bodily discharge voluntarily”. The word has its origins
from the Latin continere or teuere, which means “to hold”. The anorectum is the caudal end of the gastrointestinal tract, and is responsible for fecal continence
and defecation. In humans, defecation is a viscero somatic reflex that is often preceded by several attempts to preserve continence.
Any attempt at managing anorectal disorders requires a clear understanding of the anatomy and the integrated physiologic mechanisms
responsible for maintaining continence.
12/2006: pages 3-16;
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ABSTRACT: Continence is a highly complex physiological function requiring coordinated activity of brain and central nervous system (CNS),
autonomic and enteric nervous systems; a gastrointestinal tract of adequate length and biomechanical properties; and a competent
anal sphincter complex, many components of which remain incompletely understood. In a minority of cases, for example incontinence
immediately following fistulotomy for a high anal fistula in an otherwise “normal” individual, the cause-effect relationship
is clear. For the majority, however, temporal relationships are not so evident, e.g. onset of symptoms several decades following
a clinically uneventful vaginal delivery but one in which covert sphincter damage occurred, in which association between event
and symptoms is less clear, and in which the event may be just one component of a multifactorial aetiology. Structural sphincteric
causes of incontinence are relatively easy to investigate; at the most simplistic level, faecal continence depends upon anal
pressure being higher than rectal pressure, and that this situation may be maintained predominantly by internal anal sphincter
function, augmented at times of increased rectal pressure by voluntary anal muscle contraction, reflex or conscious, and orchestrated
by intact sensation.
12/2006: pages 43-66;
