Faecal incontinence is associated with an impaired rectosigmoid brake and improved by sacral neuromodulation

An expert's guide to classical manometric patterns seen in high-resolution colonic manometry

INTRODUCTION

High-resolution colonic manometry is a research and diagnostic tool used to evaluate colonic motility. Used in health it helps us understand normal colonic motility and the colonic response to physiological stimuli such as meal, as well as chemical (laxatives) and mechanical (distension) stimuli. In pediatric and adult patients with suspected colonic disorders, it can help to understand the abnormal colonic motility associated with the condition.

AREA COVERED

High-resolution manometric catheters contain multiple closely spaced sensors that detect intraluminal pressure changes and contractile force, which can be interpreted as contractile activity. This activity forms several distinctive motor patterns that help in understanding normal colonic physiology and provide insights into the potential pathophysiology underlying colonic disorders such as constipation. After a PubMed search of colonic high-resolution manometry studies, this review provides an overview of the characterized motor patterns, when they occur, how they are initiated, their clinical relevance, and their role, if any, in guiding therapeutic interventions.

EXPERT OPINION

High-resolution colonic manometry has identified motor patterns that were missed or mislabeled by low-resolution recordings. How best to use this information to guide treatment remains to be determined.

High output stoma after surgery for rectal cancer - a risk factor for low anterior resection syndrome?

PURPOSE

The relationship between high-output stoma (HOS) and low anterior resection syndrome (LARS) was previously unclear. This study investigated the association between HOS and major LARS in rectal cancer patients with preventive stoma.

METHODS

We conducted a retrospective analysis of 653 rectal cancer patients who underwent prophylactic ileostomy reversal after low anterior resection at the Fourth Hospital of Hebei Medical University between 2018 and 2021. Patients were categorized into HOS and non-HOS groups based on stoma output within 3 months before surgery. Major LARS was assessed using the LARS score. The association between HOS and major LARS was analyzed using multifactor logistic regression models, subgroup analyses, and smoothing curve fitting methods.

RESULTS

Among the 653 patients, 53 (8.1%) experienced HOS, and 81 (12.4%) developed major LARS after stoma closure. The HOS group exhibited a significantly higher risk of major LARS compared to the non-HOS group (P < 0.001). Multivariate logistic regression indicated that HOS was associated with a 210% increased risk of major LARS (OR: 3.10; 95% CI: 1.56, 6.14; P = 0.001). Subgroup analysis revealed that this association was more pronounced in older patients (age > 60), those without hypertension, with N0-N1 staging, a history of chemotherapy, and longer stoma closure intervals (Q3, Q4).

CONCLUSION

HOS is significantly associated with major LARS in rectal cancer patients, particularly in certain clinical subgroups. These findings suggest the need for careful management of HOS to potentially reduce LARS occurrence after stoma closure.

Sacral Neuromodulation in Patients With Low Anterior Resection Syndrome: The SANLARS Randomized Clinical Trial

BACKGROUND

Sacral neuromodulation might be effective to palliate low anterior resection syndrome after rectal cancer surgery, but robust evidence is not available.

OBJECTIVE

To assess the impact of sacral neuromodulation on low anterior resection syndrome symptoms as measured by validated scores and bowel diaries.

DESIGN

Randomized, double-blind, 2-phased, controlled, multicenter crossover trial (NCT02517853).

SETTINGS

Three tertiary hospitals.

PATIENTS

Patients with major low anterior resection syndrome 12 months after transit reconstruction after rectal resection who had failed conservative treatment.

INTERVENTIONS

Patients underwent an advanced test phase by stimulation for 3 weeks and received the pulse generator implant if a 50% reduction in low anterior resection syndrome score was achieved. These patients entered the randomized phase in which the generator was left active or inactive for 4 weeks. After a 2-week washout, the sequence was changed. After the crossover, all generators were left activated.

MAIN OUTCOME MEASURES

The primary outcome was low anterior resection syndrome score reduction. Secondary outcomes included continence and bowel symptoms.

RESULTS

After testing, 35 of 46 patients (78%) had a 50% or greater reduction in low anterior resection syndrome score. During the crossover phase, all patients showed a reduction in scores and improved symptoms, with better performance if the generator was active. At 6- and 12-month follow-up, the mean reduction in low anterior resection syndrome score was -6.2 (95% CI -8.97 to -3.43; p < 0.001) and -6.97 (95% CI -9.74 to -4.2; p < 0.001), with St. Mark's continence score -7.57 (95% CI -9.19 to -5.95, p < 0.001) and -8.29 (95% CI -9.91 to -6.66; p < 0.001). Urgency, bowel emptiness sensation, and clustering episodes decreased in association with quality-of-life improvement at 6- and 12-month follow-up.

LIMITATIONS

The decrease in low anterior resection syndrome score with neuromodulation was underestimated because of an unspecific measuring instrument. There was a possible carryover effect in sham stimulation sequence.

CONCLUSIONS

Neuromodulation provides symptoms and quality-of-life amelioration, supporting its use in low anterior resection syndrome. See Video Abstract .

NEUROMODULACIN SACRA EN PACIENTES CON SNDROME DE RESECCIN ANTERIOR BAJA ENSAYO CLNICO ALEATORIZADO SANLARS

ANTECEDENTES:La neuromodulación sacra podría ser eficaz para paliar el síndrome de resección anterior baja después de la cirugía de cáncer de recto, pero no hay pruebas sólidas disponibles.OBJETIVO:Evaluar el impacto de la neuromodulación sacra en los síntomas del síndrome de resección anterior baja, medido mediante puntuaciones validadas y diarios intestinales.DISEÑO:Ensayo cruzado multicéntrico, controlado, aleatorizado, doble ciego, de dos fases (NCT02517853).LUGARES:Tres hospitales terciarios.PACIENTES:Pacientes con puntuación de resección anterior baja importante, 12 meses después de la reconstrucción del tránsito después de la resección rectal en quienes había fracasado el tratamiento conservador.INTERVENCIONES:Los pacientes se sometieron a una fase de prueba avanzada mediante estimulación durante tres semanas y se les implantó el generador de impulsos si se lograba una reducción del 50% en la puntuación del síndrome de resección anterior baja, ingresando a la fase aleatorizada en la que el generador se dejaba activo o inactivo durante cuatro semanas. Después de observar por 2 semanas, se cambió la secuencia. Después del cruce, todos los generadores quedaron activados.PRINCIPALES MEDIDAS DE RESULTADO:El resultado primario fue la reducción de la puntuación del síndrome de resección anterior baja. Los resultados secundarios incluyeron continencia y síntomas intestinales.RESULTADOS:Después de las pruebas, 35 de 46 pacientes (78%) tuvieron una reducción ≥50% en la puntuación del síndrome de resección anterior baja. Durante el cruce, todos los pacientes mostraron una reducción en las puntuaciones y una mejora de los síntomas, con un mejor rendimiento si el generador estaba activo. A los 6 y 12 meses de seguimiento, la reducción media en la puntuación del síndrome de resección anterior baja fue -6,2 (-8,97; -3,43; p < 0,001) y -6,97 (-9,74; -4,2; p < 0,001), con Puntuación de continencia de St. Mark's -7,57 (-9,19; -5,95, p < 0,001) y -8,29 (-9,91; -6,66; p < 0,001). La urgencia, la sensación de vacío intestinal y los episodios de agrupamiento disminuyeron en asociación con una mejora en la calidad de vida a los 6 y 12 meses de seguimiento.LIMITACIONES:La disminución en la puntuación del síndrome de resección anterior baja con neuromodulación se subestimó debido a un instrumento de medición no específico. Posible efecto de arrastre en la secuencia de estimulación simulada.CONCLUSIONES:La neuromodulación mejora los síntomas y la calidad de vida, lo que respalda su uso en el síndrome de resección anterior baja. (Traducción-Dr. Mauricio Santamaria ).

From the organ bath to the whole person: a review of human colonic motility

Motor function of the colon is essential for health. Our current understanding of the mechanisms that underlie colonic motility are based upon a range of experimental techniques, including molecular biology, single cell studies, recordings from muscle strips, analysis of part or whole organ ex vivo through to in vivo human recordings. For the surgeon involved in the clinical management of colonic conditions this amounts to a formidable volume of material. Here, we synthesize the key findings from these various experimental approaches so that surgeons can be better armed to deal with the complexities of the colon.

Validation of body surface colonic mapping (BSCM) against high resolution colonic manometry for evaluation of colonic motility

Abnormal cyclic motor pattern (CMP) activity is implicated in colonic dysfunction, but the only tool to evaluate CMP activity, high-resolution colonic manometry (HRCM), remains expensive and not widely accessible. This study aimed to validate body surface colonic mapping (BSCM) through direct correlation with HRCM. Synchronous meal-test recordings were performed in asymptomatic participants with intact colons. A signal processing method for BSCM was developed to detect CMPs. Quantitative temporal analysis was performed comparing the meal responses and motility indices (MI). Spatial heat maps were also compared. Post-study questionnaires evaluated participants' preference and comfort/distress experienced from either test. 11 participants were recruited and 7 had successful synchronous recordings (5 females/2 males; median age: 50 years [range 38-63]). The best-correlating MI temporal analyses achieved a high degree of agreement (median Pearson correlation coefficient (Rp) value: 0.69; range 0.47-0.77). HRCM and BSCM meal response start and end times (Rp = 0.998 and 0.83; both p < 0.05) and durations (Rp = 0.85; p = 0.03) were similar. Heat maps demonstrated good spatial agreement. BSCM is the first non-invasive method to be validated by demonstrating a direct spatio-temporal correlation to manometry in evaluating colonic motility.

Clinical utility of trans-sacral magnetic stimulation-evoked sphincter potentials and high-density electromyography in pelvic floor assessment: Technical evaluation

AIM

Faecal incontinence is common and of multifactorial aetiologies, yet current diagnostic tools are unable to assess nerve and sphincter function objectively. We developed an anorectal high-density electromyography (HD-EMG) probe to evaluate motor-evoked potentials induced via trans-sacral magnetic stimulation (TSMS).

METHOD

Anorectal probes with an 8 × 8 array of electrodes spaced 1 cm apart were developed for recording HD-EMG of the external anal sphincter. These HD-EMG probes were used to map MEP amplitudes and latencies evoked via TSMS delivered through the Magstim Rapid2 (MagStim Company). Patients undergoing pelvic floor investigations were recruited for this IDEAL Stage 2a pilot study.

RESULTS

Eight participants (median age 49 years; five female) were recruited. Methodological viability, safety and diagnostic workflow were established. The test was well tolerated with median discomfort scores ≤2.5/10, median pain scores ≤1/10 and no adverse events. Higher Faecal Incontinence Severity Index scores correlated with longer MEP latencies (r = 0.58, p < 0.001) and lower MEP amplitudes (r = -0.32, p = 0.046), as did St. Mark's Incontinence Scores with both MEP latencies (r = 0.49, p = 0.001) and MEP amplitudes (r = -0.47, p = 0.002).

CONCLUSION

This HD-EMG probe in conjunction with TSMS presents a novel diagnostic tool for anorectal function assessment. Spatiotemporal assessment of magnetically stimulated MEPs correlated well with symptoms and offers a feasible, safe and patient-tolerable method of evaluating pudendal nerve and external anal sphincter function. Further clinical development and evaluation of these techniques is justified.

Management of Low Anterior Resection Syndrome (LARS) Following Resection for Rectal Cancer

INTRODUCTION

A total of 60-80% of patients undergoing rectal resection (mostly as a treatment for rectal cancer) suffer from a variety of partly severe functional problems despite preservation of the anal sphincter. These patients are summarized under the term low anterior resection syndrome (LARS). Preoperative radiotherapy, vascular dissection and surgical excision of the low rectum and mesorectum lead, alone or all together, to a significant impairment of colonic and (neo-) rectal motility. This results in a variety of symptoms (multiple defecation episodes, recurrent episodes of urge, clustering, incontinence, etc.) which are associated with severe impairment of quality of life (QOL).

METHODS

This narrative review summarizes the present state of knowledge regarding the pathophysiology of LARS as well as the evidence for the available treatment options to control the symptoms resulting from this condition.

RESULTS

A review of the literature (Medline, Pubmed) reveals a variety of treatment options available to control symptoms of LARS. Medical therapy, with or without dietary modification, shows only a modest effect. Pelvic floor rehabilitation consisting of muscle exercise techniques as well as biofeedback training has been associated with improvement in LARS scores and incontinence, albeit with limited scientific evidence. Transanal irrigation (TAI) has gained interest as a treatment modality for patients with LARS due to an increasing number of promising data from recently published studies. Despite this promising observation, open questions about still-unclear issues of TAI remain under debate. Neuromodulation has been applied in LARS only in a few studies with small numbers of patients and partly conflicting results.

CONCLUSION

LARS is a frequent problem after sphincter-preserving rectal surgery and leads to a marked impairment of QOL. Due to the large number of patients suffering from this condition, mandatory identification, as well as treatment of affected patients, must be considered during surgical as well as oncological follow-up. The use of a standardized treatment algorithm will lead to sufficient control of symptoms and a high probability of a marked improvement in QOL.

The role of colonic motility in low anterior resection syndrome

Low anterior resection syndrome (LARS) describes the symptoms and experiences of bowel dysfunction experienced by patients after rectal cancer surgery. LARS is a complex and multifactorial syndrome exacerbated by factors such as low anastomotic height, defunctioning of the colon and neorectum, and radiotherapy. There has recently been growing awareness and understanding regarding the role of colonic motility as a contributing mechanism for LARS. It is well established that rectosigmoid motility serves an important role in coordinating rectal filling and maintaining continence. Resection of the rectosigmoid may therefore contribute to LARS through altered distal colonic and neorectal motility. This review evaluates the role of colonic motility within the broader pathophysiology of LARS and outlines future directions of research needed to enable targeted therapy for specific LARS phenotypes.