Understanding and Tailored Treatment of Low Anterior Resection Syndrome

St Mark's Incontinence score

Description: The St. Mark's Incontinence Score assesses the severity of fecal incontinence across multiple domains, including incontinence to gas, liquid, and solid stool, urgency, use of pads, and lifestyle impact. Score range and direction: Total score ranges from 0 to 24. Higher scores indicate more severe fecal incontinence.

Time frame: • Applied at baseline and four weeks into all treatment periods

Colostomy Impact Score

The Colostomy Impact Score is a disease-specific questionnaire evaluating the impact of living with a colostomy on daily functioning, social participation, body image, and emotional well-being. Score range and direction: Total score ranges from 0 to 100. Higher scores indicate greater negative impact of the colostomy on quality of life.

Time frame: From baseline visit to the end of each standardized treatments at 4 weeks

Bristol Stool Form Scale

The Bristol Stool Form Scale classifies stool consistency into seven categories ranging from hard, lumpy stools to entirely liquid stools. It is used as an indicator of bowel transit and stool form. Score range and direction: Scale ranges from Type 1 to Type 7. Lower types (1-2) indicate harder stools and slower transit. Middle types (3-4) indicate normal stool form. Higher types (6-7) indicate loose or watery stools and faster transit.

Time frame: From baseline visit to the end of each standardized treatments at 4 weeks

Patient Assessment of Constipation Symptoms (PAC-SYM)

The Patient Assessment of Constipation Symptoms questionnaire measures symptom severity in constipation across three domains: abdominal symptoms, stool symptoms, and rectal symptoms. Score range and direction: Each item is scored 0-4; total score ranges from 0 to 48. Higher scores indicate more severe constipation symptoms.

Time frame: From baseline visit to the end of each standardized treatments at 4 weeks

Wexner Incontinence Score

The Wexner Incontinence Score evaluates the severity of fecal incontinence based on frequency of incontinence to gas, liquid, and solid stool, need for pads, and lifestyle alteration. Score range and direction: Total score ranges from 0 to 20. Higher scores indicate more severe fecal incontinence.

Time frame: From baseline visit to the end of each standardized treatments at 4 weeks

Hospital Anxiety and Depression Scale (HADS)

The Hospital Anxiety and Depression Scale assesses symptoms of anxiety and depression in medical populations. It consists of two subscales: HADS-Anxiety and HADS-Depression. Score range and direction: Each subscale ranges from 0 to 21. Higher scores indicate more severe symptoms of anxiety or depression. Total score (0-42) may be reported but is less commonly used.

Time frame: From baseline visit to the end of each standardized treatments at 4 weeks

Whole gut and segmental transit times as measured with 3D-Transit

Whole-gut and segmental gastrointestinal transit times are measured using the Motilis 3D-Transit system. The system tracks the movement of an electromagnetic capsule through the gastrointestinal tract, allowing calculation of segmental transit times (stomach, small intestine, colon) and total whole-gut transit time. This measure evaluates gastrointestinal motility patterns at baseline. Score range and direction: Transit times are continuous measures reported in minutes or hours. There is no fixed upper or lower limit, as transit times vary physiologically between individuals. Longer transit times indicate slower gastrointestinal motility. Shorter transit times indicate faster gastrointestinal motility.

Time frame: At baseline

Colonic and segmental colonic volumes

Magnetic resonance imaging is used at baseline to quantify total colonic volume and segmental colonic volumes (ascending, transverse, descending, sigmoid/rectum colon). Volumes are derived from semi-automated segmentation of the colon on T2-weighted images. This measure evaluates baseline colonic morphology and storage capacity. Score range and direction: Colonic volumes are continuous measures reported in milliliters (mL). There is no fixed upper or lower limit, as volumes vary physiologically between individuals. Higher values indicate larger colonic or segmental volume. Lower values indicate smaller colonic or segmental volume.

Time frame: At baseline

Resting Anal Pressure Measured by High-Resolution Anorectal Manometry

Resting anal pressure will be measured using high-resolution anorectal manometry according to standard manometric protocols. Resting anal pressure reflects basal anal sphincter tone, primarily related to internal anal sphincter function. The outcome will be reported as a continuous physiological measure in millimeters of mercury (mmHg). There are no fixed minimum or maximum values because pressures vary physiologically between individuals. Higher values indicate higher resting anal sphincter tone, while lower values indicate reduced resting sphincter tone.

Time frame: At baseline

Maximal Voluntary Anal Squeeze Pressure Measured by High-Resolution Anorectal Manometry

Maximal voluntary anal squeeze pressure will be measured using high-resolution anorectal manometry according to standard manometric protocols. Squeeze pressure reflects voluntary external anal sphincter contractile strength. The outcome will be reported as a continuous physiological measure in millimeters of mercury (mmHg). There are no fixed minimum or maximum values because pressures vary physiologically between individuals. Higher values indicate stronger voluntary anal sphincter contraction, while lower values indicate reduced voluntary sphincter contractile function.

Time frame: At baseline

Rear-Front Pressure Gradient Measured by the Fecobionics Device

The rear-front pressure gradient will be measured using the Fecobionics device during simulated stool evacuation. The Fecobionics device records axial pressure patterns during defecation. The rear-front pressure gradient reflects the pressure difference between the rear and front sensors of the device during evacuation and provides a measure of propulsive force relative to outlet resistance. The outcome will be reported as a continuous physiological measure in millimeters of mercury (mmHg). There are no fixed minimum or maximum values because values vary physiologically between individuals. Higher values indicate stronger propulsive pressure relative to outlet resistance, whereas lower values may indicate impaired propulsion or increased outlet resistance.

Time frame: At baseline

Compare the physiological findings in LARS patients with controls

Compare the physioligal findings in LARS patients with a) no-LARS patients, b) organ-preservation patients and c) patient with fecal incontinence

Time frame: At baseline

Investigate the physiological changes in anorectal function associated with neuromodulation in patients with urge fecal incontinence

Changes in anorectal function measured by the Fecobionics Device

Time frame: From baseline to after 30 minutes of active neuromodulation

Investigate the physiological changes in anorectal function associated with neuromodulation in patients with urge fecal incontinence

Changes in anorectal function measured by high-resolution anorectal manometry

Time frame: From baseline to after 30 minutes of active neuromodulation

Investigate the physiological changes in anorectal function associated with neuromodulation in patients with fecal incontinence

Changes in anorectal function measured by the Fecobionics Device

Time frame: From baseline to after active neuromodulation at Visit 2

Investigate the physiological changes in anorectal function associated with neuromodulation in patients with fecal incontinence

Changes in anorectal function measured by high-resolution anorectal manometry

Time frame: From baseline to after active neuromodulation at Visit 2

Change in VAS Urgency Score From Before to During Stimulation at the Baseline Visit

The participant's perceived urgency to defecate during the examination will be assessed using a visual analogue scale. Participants with fecal incontinence will rate their urgency to defecate on a numeric scale from 0 to 10, where 0 indicates no desire to defecate and 10 indicates maximal urgency. The outcome will be reported as the change in VAS urgency score from the pre-stimulation assessment to the stimulation assessment at the baseline visit. Higher scores indicate stronger urgency to defecate.

Time frame: Baseline visit: immediately before stimulation and during active stimulation

Resting-State Electroencephalography

Resting-state electroencephalography is recorded with the participant at rest to assess baseline cortical activity patterns. Measures include spectral power across standard frequency bands (theta, alpha, beta). Score range and direction: Spectral power values are continuous and do not have fixed upper limits. Higher or lower values reflect differences in cortical activity depending on frequency band.

Time frame: At baseline

Evoked Potential Amplitude During Rectal Balloon Distension

Electroencephalography is recorded during rapid rectal balloon distension to elicit cortical evoked potentials. The primary measure is the amplitude of the evoked response to visceral stimulation. Score range and direction: Amplitude is measured in microvolts (µV). Higher amplitudes indicate stronger cortical responses to visceral stimulation.

Time frame: At baseline

Evoked Potential Latency During Rectal Balloon Distension

Electroencephalography is recorded during rectal balloon distension to measure the latency of cortical evoked potentials, reflecting the timing of sensory pathway activation. Score range and direction: Latency is measured in milliseconds (ms). Longer latencies indicate slower or delayed cortical processing. Shorter latencies indicate faster neural conduction.

Time frame: At baseline

Defecation Index Measured by the Fecobionics Device

The defecation index will be derived from Fecobionics measurements obtained during simulated stool evacuation. The index summarizes expulsion performance and anorectal function based on prespecified Fecobionics-derived variables. The outcome will be reported as a continuous index value. There are no fixed minimum or maximum values. Higher values indicate more efficient expulsion and better defecatory performance, whereas lower values indicate reduced defecatory performance.

Time frame: Baseline