Patient-reported and physician-recorded bowel dysfunction following colorectal resection and radical cystectomy: a prospective, comparative study.

AIM: Bowel dysfunction following anterior resection (AR) is termed low anterior resection syndrome. It is unclear whether such dysfunction occurs following other bowel/pelvic operations as well. This study aimed to characterize and compare bowel dysfunction following AR, right hemicolectomy (RH) and radical cystectomy (RC). METHOD: A prospective study of consecutive patients undergoing AR, RH and RC (2002-2012) was performed at a tertiary referral centre in Sydney, Australia. Outcome measures included (i) patient-reported satisfaction with bowel function, self-described bowel function and self-reported change in bowel function; (ii) objective assessment of bowel function using validated criteria to identify symptoms and stratify patients into those with constipation and/or faecal incontinence (FI); and (iii) health-related quality of life (SF-36v2 Health Survey). RESULTS: Of 743 eligible patients, 70% participated [AR, n = 338, mean age 69.6 years (SD 11.9), 59% men; RH, n = 150, 75.8 years (SD 10.5), 54% men; RC, n = 34, 71.1 years (SD 14.1), 71% men]. AR patients were three times more likely to report change in bowel function post-surgery and self-judged their bowel function as abnormal more frequently (64%) than RH patients (35%) and RC patients (35%) (P < 0.01). AR patients were four times more likely to meet criteria for concomitant constipation and FI. Patients with concomitant constipation and FI had lower physical and mental SF-36v2 scores (P < 0.001). CONCLUSION: Bowel dysfunction occurred after RH and RC but rates were higher following AR. This suggests that low anterior resection syndrome occurs due to a direct impact of partial/complete loss of the rectum rather than just due to loss of bowel length and/or the consequence(s) of pelvic dissection.

Colonic transit in patients after anterior resection: prospective, comparative study using single-photon emission CT/CT scintigraphy.

BACKGROUND: Bowel dysfunction after anterior resection is well documented, but its pathophysiology remains poorly understood. No study has assessed whether postoperative variation in colonic transit contributes to symptoms. This study measured colonic transit using planar scintigraphy and single-photon emission CT (SPECT)/CT in patients after anterior resection, stratified according to postoperative bowel function. METHODS: Symptoms were assessed using the low anterior resection syndrome (LARS) score. Following gallium-67 ingestion, scintigraphy was performed at predefined time points. Nine regions of interest were defined, and geometric centre (GC), percentage isotope retained, GC velocity index and colonic half-clearance time (T½ ) determined. Transit parameters were compared between subgroups based on LARS score using receiver operating characteristic (ROC) curve analyses. RESULTS: Fifty patients (37 men; median age 72·6 (range 44·4-87·7) years) underwent planar and SPECT scintigraphy. Overall, 17 patients had major and nine had minor LARS; 24 did not have LARS. There were significant differences in transit profiles between patients with major LARs and those without LARS: GCs were greater (median 5·94 (range 2·35-7·72) versus 4·30 (2·12-6·47) at 32 h; P = 0·015); the percentage retained isotope was lower (median 53·8 (range 6·5-100) versus 89·9 (38·4-100) per cent at 32 h; P = 0·002); GC velocity indices were greater (median 1·70 (range 1·18-1·92) versus 1·45 (0·98-1·80); P = 0·013); and T½ was shorter (median 38·3 (17·0-65·0) versus 57·0 (32·1-160·0) h; P = 0·003). Percentage tracer retained at 32 h best discriminated major LARS from no LARS (area under curve (AUC) 0·828). CONCLUSION: Patients with major LARS had accelerated colonic transit compared with those without LARS, which may help explain postoperative bowel dysfunction in this group. The percentage tracer retained at 32 h had the greatest AUC value in discriminating such patients.

ANTECEDENTES: La disfunción intestinal después de la resección anterior (anterior resection, AR) está bien documentada, pero su fisiopatología sigue siendo poco conocida. Ningún estudio ha evaluado si la variación postoperatoria en el tránsito colónico contribuye a los síntomas. Este estudio midió el tránsito colónico mediante gammagrafía planar con SPECT/CT en pacientes después de una AR, estratificados según la función intestinal postoperatoria. MÉTODOS: Los síntomas se evaluaron mediante el sistema de puntuación del síndrome de resección anterior baja (low anterior resection syndrome, LARS). Después de la administración oral de galio-67, se realizó una gammagrafía en tiempos predefinidos. Se establecieron nueve regiones de interés y se midió/calculó las siguientes variables: (i) centro geométrico (geometric centre, GC); (ii) porcentaje de isótopo retenido; (iii) velocidad del GC; y (iv) semivida de aclaramiento del colon (T1/2). Se compararon los parámetros de tránsito en diferentes subgrupos de pacientes de acuerdo con su puntuación LARS utilizando análisis de curva ROC RESULTADOS: La gammagrafía planar con SPECT se realizó en 50 pacientes con AR seleccionados al azar (37 varones, media de 72,3 años (DE 9,0)). En total, 17 pacientes presentaban un LARS mayor, 9 tenían un LARS menor y 24 no presentaban LARS. En comparación con los pacientes sin LARS, los pacientes con LARS mayor tenían perfiles de tránsito significativamente diferentes: a las 32 horas, (i) los GC fueron mayores (mediana 5,94 (rango 2,35-7,72) versus 4,30 (2,12-6,47), P = 0,015)); (ii) el porcentaje de isótopo retenido fue menor (mediana 53,8% (error estándar de la media 6,5) versus 89,9% (3,4), P = 0,002)); (iii) las velocidades del GC fueron mayores (1,70 (1,18-1,92) versus 1,45 (0,98-1,80), P = 0,013)); y (iv) las semividas T1/2 fueron más cortas (38,3 horas (17,0-65,0) versus 57,0 (32,1-160), P = 0,003)). El porcentaje de isótopo retenido a las 32 horas fue el parámetro que mejor discriminó los pacientes con LARS mayor de los pacientes sin LARS (AUC 0,828). CONCLUSIÓN: Los pacientes con LARS mayor presentaron un tránsito colónico acelerado en comparación con los pacientes sin LARS, lo que puede contribuir a explicar la disfunción intestinal postoperatoria en dichos pacientes. El marcador de porcentaje de isótopo retenido a las 32 horas tenía un valor de AUC más elevado en la discriminación de estos pacientes.

Quantification and neurochemical coding of the myenteric plexus in humans: No regional variation between the distal colon and rectum.

BACKGROUND: It remains unclear whether regional variation exists in the human enteric nervous system (ENS) ie, whether intrinsic innervation varies along the gut. Recent classification of gastrointestinal neuropathies has highlighted inadequacies in the quantification of the human ENS. This study used paired wholemounts to accurately quantify and neurochemically code the hindgut myenteric plexus, comparing human distal colon and rectum. METHODS: Paired human descending colonic/rectal specimens were procured from 15 patients undergoing anterior resection. Wholemounts of myenteric plexi were triple-immunostained with anti-Hu/NOS/ChAT antibodies. Images were acquired by motorized epifluorescence microscopy, allowing assessment of ganglionic density/size, ganglionic area density, and neuronal density. 'Stretch-corrected' values were calculated using stretched/relaxed tissue dimensions. KEY RESULTS: Tile-stitching created a collage with average area 99 300 000 µm2 . Stretch-corrected ganglionic densities were similar (colon: median 510 ganglia/100 mm2 [range 386-1170], rectum: 585 [307-923]; P = .99), as were average ganglionic sizes (colon: 57 593 µm2 [40 301-126 579], rectum: 54 901 [38 701-90 211], P = .36). Ganglionic area density (colon: 11.92 mm2 per 100 mm2 [7.53-18.64], rectum: 9.84 [5.80-17.19], P = .10) and stretch-corrected neuronal densities (colon: 189 neurons/mm2 [117-388], rectum: 182 [89-361], P = .31) were also similar, as were the neurochemical profiles of myenteric ganglia, with comparable proportions of NOS+ and ChAT+ neurons (P > .10). CONCLUSIONS AND INFERENCES: This study has revealed similar neuronal and ganglionic densities and neurochemical profiles in human distal colon and rectum. Further investigation of other components of the ENS, incorporating additional immunohistochemical markers are required to confirm that there is no regional variation in the human hindgut ENS.

Brain responses to mechanical rectal stimulation in patients with faecal incontinence: an fMRI study.

AIM: Continence is dependent on anorectal-brain interactions. Consequently, aberrations of the brain-gut axis may be important in the pathophysiology of faecal incontinence (FI) in certain patients. The aim of this study was to assess the feasibility of recording brain responses to rectal mechanical stimulation in patients with FI using functional magnetic resonance imaging (fMRI). METHOD: A prospective, cohort pilot study was performed to assess brain responses during rectal stimulation in 14 patients [four men, mean (SD) age 62 (15) years]. Blood oxygen level dependent (BOLD) signals were measured by fMRI during rest and mechanical distension, involving random repetitions of isobaric phasic rectal distensions at fixed (15 and 45 mmHg) and variable (10% above sensory perception threshold) pressures. RESULTS: Increases in BOLD signals in response to high pressure rectal distension (45 mmHg) and maximum toleration were observed in the cingulate gyrus, thalamus, insular cortex, inferior frontal gyrus, cerebellum, caudate nucleus, supramarginal gyrus, putamen and amygdala. Additionally, activation of the supplementary motor cortex and caudate nucleus with inconsistent activity in the frontal lobe was observed. CONCLUSIONS: This study has demonstrated the feasibility of recording brain responses to rectal mechanical stimulation using fMRI in patients with FI, revealing activity in widespread areas of the brain involved in visceral sensory processing. The observed activity in the supplementary motor cortex and caudate nucleus, with relative paucity of activity in the frontal lobes, warrants investigation in future studies to determine whether aberrations in cerebral processing of rectal stimuli play a role in the pathogenesis of FI.

Building a sustainable clinical academic workforce to meet the future healthcare needs of Australia and New Zealand: report from the first summit meeting.

The delivery of healthcare that meets the requirements for quality, safety and cost-effectiveness relies on a well-trained medical workforce, including clinical academics whose career includes a specific commitment to research, education and/or leadership. In 2011, the Medical Deans of Australia and New Zealand published a review on the clinical academic workforce and recommended the development of an integrated training pathway for clinical academics. A bi-national Summit on Clinical Academic Training was recently convened to bring together all relevant stakeholders to determine how best to do this. An important part understood the lessons learnt from the UK experience after 10 years since the introduction of an integrated training pathway. The outcome of the summit was to endorse strongly the recommendations of the medical deans. A steering committee has been established to identify further stakeholders, solicit more information from stakeholder organisations, convene a follow-up summit meeting in late 2015, recruit pilot host institutions and engage the government and future funders.

Prevalence of functional bowel disorders and faecal incontinence: an Australian primary care survey.

AIM: Interest in functional bowel disorders (FBDs) and faecal incontinence (FI) has increased amongst coloproctologists. The study aimed to assess the prevalence of FBDs and FI (including its severity) among Australian primary healthcare seekers using objective criteria. METHOD: A cross-sectional survey was conducted in a primary care setting in Sydney, Australia. A self-administered questionnaire was used to collect demographic information and diagnose FBDs (irritable bowel syndrome, constipation, functional bloating and functional diarrhoea) based on Rome III criteria. The severity of FI was determined using the Vaizey incontinence score. Associations with medical/surgical history and healthcare utilization were assessed. RESULTS: Of 596 subjects approached, 396 (66.4%) agreed to participate. Overall, 33% had FBD and/or FI. Irritable bowel syndrome was present in 11.1% and these participants were more likely to report anxiety/depression (P < 0.01) and to have had a previous colonoscopy (P < 0.001) or cholecystectomy (P = 0.02). Functional constipation was present in 8.1%, and functional bloating and functional diarrhoea were diagnosed in 6.1%, and 1.5%, respectively. FI was present in 12.1% with the majority (52%) reporting moderate/severe incontinence (Vaizey score > 8). Participants with FI were more likely to have irritable bowel syndrome, urinary incontinence and previous anal surgery (P < 0.01). CONCLUSION: FBDs and FI are prevalent conditions amongst primary healthcare seekers and the needs of those affected appear to be complex given their coexisting symptoms and conditions. Currently, the majority do not reach colorectal services, although increased awareness by primary care providers could lead to sufferers being referred for specialist management.

Evacuation proctography: a reappraisal of normal variability.

AIM: Interpretation of evacuation proctography (EP) images is reliant on robust normative data. Previous studies of EP in asymptomatic subjects have been methodologically limited. The aim of this study was to provide parameters of normality for both genders using EP. METHOD: Evacuation proctography was prospectively performed on 46 healthy volunteers (28 women). Proctograms were independently analysed by two reviewers. All established and some new variables of defaecatory structure and function were assessed objectively: anorectal dimensions; anorectal angle changes; evacuation time; percentage contrast evacuated; and incidence of rectal wall morphological 'abnormalities'. RESULTS: Normal ranges were calculated for all main variables. Mean end-evacuation time was 88 s (95% CI: 63-113) in male subjects and 128 s (95% CI: 98-158) in female subjects; percentage contrast evacuated was 71% (95% CI: 63-80) in male subjects and 65% (95% CI: 58-72) in female subjects. Twenty-six (93%) of 28 female subjects had a rectocoele with a mean depth of 2.5 cm (upper limit = 3.9 cm). Recto-rectal intussusception was found in nine subjects (approximately 20% of both genders); however, recto-anal intussusception was not observed. Only rectal diameter differed significantly between genders. Qualitatively, three patterns of evacuation were present. CONCLUSION: This study defines normal ranges for anorectal dimensions and parameters of emptying, as well as the incidence and characteristics of rectal-wall 'abnormalities' observed or derived from EP. These ranges can be applied clinically for subsequent disease comparison.

Neuroanatomy and physiology of colorectal function and defaecation: from basic science to human clinical studies.

Colorectal physiology is complex and involves programmed, coordinated interaction between muscular and neuronal elements. Whilst a detailed understanding remains elusive, novel information has emerged from recent basic science and human clinical studies concerning normal sensorimotor mechanisms and the organization and function of the key elements involved in the control of motility. This chapter summarizes these observations to provide a contemporary review of the neuroanatomy and physiology of colorectal function and defaecation.

Pathophysiology of evacuation disorders.

This review details our contemporary knowledge of the mechanisms underlying evacuatory disorders. There is confusion concerning terminology and classification, which is based upon both an incomplete understanding of the multiple mechanisms involved in evacuation, and that current tests to investigate it are not physiological. Nevertheless, despite the need for more research, significant advances have been made and current assessments can direct therapy.

Rectal hyposensitivity: pathophysiological mechanisms.

Rectal hyposensitivity (RH) relates to a diminished perception of rectal distension. It may occur due to afferent nerve dysfunction and/or secondary to abnormal structural or biomechanical properties of the rectum. The aim of this study was to determine the contribution of these underlying pathophysiological mechanisms by systematically evaluating rectal diameter, compliance and afferent nerve sensitivity in patients with RH, using methodology employed in clinical practice. The study population comprised 45 (33 women; median age 48, range 25-72 years) constipated patients (Rome II criteria) with RH and 20 with normal rectal sensitivity on balloon distension and 20 healthy volunteers. Rectal diameter was measured at minimum distending pressure during isobaric distension under fluoroscopic screening. Rectal compliance was assessed during phasic isobaric distension by measuring the slope of the pressure-volume curve. Electrical stimulation of the rectal mucosa was employed to determine afferent nerve function. Values were compared to normal ranges established in healthy volunteers. The upper limits of normal for rectal diameter, compliance and electrosensitivity were 6.3 cm, 17.9 mL mmHg(-1) and 21.3 mA respectively. Among patients with RH, rectal diameter, but not compliance, was increased above the normal range (megarectum) in seven patients (16%), two of whom had elevated electrosensitivity thresholds. Rectal diameter and compliance were elevated in 23 patients (51%), nine of whom had elevated electrosensitivity thresholds. The remaining 15 patients (33%) with RH had normal rectal compliance and diameter, all of whom had elevated electrosensitivity thresholds. Two-third of the patients with RH on simple balloon distension have elevated rectal compliance and/or diameter, suggesting that impaired perception of rectal distension is due to inadequate stimulation of the rectal afferent pathway. However, a proportion of such patients also appear to have impaired nerve function. In the remaining one-third of the patients, rectal diameter and compliance are normal, while electrosensitivity thresholds are elevated, suggestive of true impaired afferent nerve function. Identification of these subgroups of patients with RH may have implications regarding their management.

Novel concepts in the diagnosis, pathophysiology and management of idiopathic megabowel.

A proportion of patients with intractable constipation have persistent dilatation of the bowel, which in the absence of an organic cause is termed idiopathic megabowel (IMB). Whilst uncommon, this condition results in considerable morbidity. Traditional methods of identifying such patients are associated with inherent methodological limitations with anorectal manometry and contrast studies overestimating and underestimating the prevalence of the condition, respectively. Recently, controlled, pressure-based distension during fluoroscopic imaging has allowed more accurate identification of patients on the basis of a rectal diameter > 6.3 cm at the minimum distension pressure. Histopathological abnormalities of all three final effectors of sensorimotor function have been reported, although it remains unclear whether these changes are primary, secondary or epiphenomic. Physiological abnormalities of sensorimotor function, namely impaired perception of rectal distension and delayed colonic transit are well documented in patients with IMB. Further, the recent demonstration of two subgroups of patients, defined on the basis of rectal compliance, suggests the possibility that they differ pathophysiologically, although the clinical relevance of this distinction is uncertain. Surgery is performed when conservative therapy is ineffective or poorly tolerated. Numerous procedures have been attempted with variable success rates and significant mortality and morbidity. Surgery should preferably be performed in specialist centres given the relative infrequency with which such patients are encountered, and that they require comprehensive clinical, psychological and physiological evaluation preoperatively.

Rectal hyposensitivity: evaluation of anal sensation in female patients with refractory constipation with and without faecal incontinence.

Rectal hyposensitivity (RH) is commonly found in patients with intractable constipation, faecal incontinence or both. Anal sensation may also be blunted in these conditions. We aimed to determine whether RH is associated with anal hyposensitivity, which may reflect a combined viscero-somatic neuropathy. One hundred and fifty-eight female patients with chronic constipation underwent physiological investigation including rectal sensation to volumetric balloon distension, and distal anal mucosal sensation to electrostimulation. Data were also obtained from 32 healthy female volunteers. Anal mucosal electrosensory thresholds were significantly higher in patients compared with volunteers (median: 2.4 mA, range: 0.4-19.6 vs 1.1 mA, range: 0.1-4.2, respectively), although the patient group was older (P < 0.0001), but there was no difference (P = 0.572) in the incidence of blunted anal sensation between those with normal rectal sensation (n = 113, 20% abnormal) and RH (n = 45, 24% abnormal). Irrespective of rectal sensory function, there was a strong association between symptom duration (P = 0.012) and anal hyposensitivity. One-fifth of constipated female patients had evidence of diminished anal sensation. However, the presence of RH was not associated with an increased frequency of anal hyposensitivity, thereby suggesting that different aetiopathogenic mechanisms underlie the development of anal and rectal hyposensitivity. Further studies in carefully selected, homogenous patient populations are necessary to elucidate these mechanisms.

Rectal intussusception in symptomatic patients is different from that in asymptomatic volunteers.

BACKGROUND: Rectal intussusception is a common finding at evacuation proctography in both symptomatic and asymptomatic individuals. Little information exists, however, as to whether intussusception morphology differs between patients with evacuatory dysfunction and healthy volunteers. METHODS: Thirty patients (19 women; median age 44 (range 21-76) years) with disordered rectal evacuation, in whom an isolated intussusception was seen on proctography, were studied. Various morphological parameters were measured, and compared with those from 11 asymptomatic controls (six women; median age 30 (range 24-38) years) found, from 31 volunteers, to have rectal intussusception. Intussusceptum thickness greater than 3 mm was designated as full thickness. Intussuscepta impeding evacuation were deemed to be occluding. RESULTS: Twenty-two patients had full-thickness intussusception, compared with two controls (P = 0.003). Intussusceptum thickness was significantly greater in the symptomatic group (anterior component: P = 0.004; posterior: P = 0.011). Twenty patients in the symptomatic group, but only three subjects in the control group, had a mechanically occluding intussusception (P = 0.043), although only three patients demonstrated evacuatory dynamics outside the normal range. CONCLUSION: Rectal intussusception in patients with evacuatory dysfunction is more advanced morphologically than that seen in asymptomatic controls; it is predominantly full thickness in patients and mucosal in controls. However, caution is required when selecting patients for intervention based solely on radiological findings.

Medium-term results of vertical reduction rectoplasty and sigmoid colectomy for idiopathic megarectum.

BACKGROUND: Vertical reduction rectoplasty (VRR) was devised specifically to address the physiological abnormalities present in the rectum of patients with idiopathic megarectum (IMR). This study evaluated the medium-term clinical and physiological results of VRR. METHODS: VRR and sigmoid colectomy was performed in ten patients with IMR and constipation (six women). Patients were evaluated before and a median of 60 (range 28-74) months after surgery by assessment of symptoms using scoring systems and anorectal physiological measurements. Independent, detailed postoperative evaluation of rectal diameter, compliance, and sensory and evacuatory function was performed. RESULTS: There were no deaths or late complications. Symptoms recurred necessitating permanent ileostomy formation in two patients. Median (range) constipation scores improved from 22 (18-27) before to 10 (0-24) after surgery (P = 0.016). Median (range) bowel frequency increased from 1.5 (0.2-7) to 7 (0.5-21) per week (P = 0.016). Rectal diameter, compliance and sensory function were normal in seven of eight patients after surgery. Evacuatory function and colonic transit were each normalized in two of eight patients after VRR. CONCLUSION: VRR corrected rectal diameter, compliance and sensory function in most patients, and clinical benefit was sustained in the medium term. The procedure was associated with a low morbidity, and no mortality and should be considered in the surgical management of IMR.

Clinical and physiological findings, and possible aetiological factors of rectal hyposensitivity.

BACKGROUND: Rectal hyposensitivity (RH) relates to insensitivity of the rectum on anorectal physiological investigation and appears common in functional bowel disorders. The clinical significance of this physiological abnormality is unclear. METHOD: RH was defined as one or more sensory threshold volumes raised beyond the normal range (mean plus two standard deviations) on rectal balloon distension. Clinical information and results of other anorectal physiological investigations were evaluated in 261 patients with RH. RESULTS: Patients with RH most commonly presented with constipation (48 per cent), constipation and incontinence in combination (27 per cent), or faecal incontinence (20 per cent). Thirty-eight per cent of patients had a history of previous pelvic surgery, 22 per cent a history of anal surgery and 13 per cent a history of spinal trauma. In patients with RH presenting with symptoms of constipation or incontinence, impaired rectal sensation was the only abnormality on physiological investigation in 48 per cent and 31 per cent respectively. CONCLUSION: Patients with RH display marked heterogeneity in terms of presenting symptoms. The exact causes of RH are unknown, but there is evidence to suggest that pelvic nerve injury and spinal trauma are possible aetiological factors. RH appears important in the aetiology of both constipation and faecal incontinence, and may be useful as a predictor of surgical outcome.