Efficacy and Safety of Transcutaneous Posterior Tibial Nerve Stimulation on Fecal Continence in Patients Undergoing Surgery for Rectal Neoplasia

实验性的：Intervention group

Posterior tibial nerve stimulation with Beurer EM-49 digital neuroestimulator at complete doses

设备：Posterior tibial nerve stimulation intervention group

In the intervention group, Beurer EM-49 digital neurostimulator will be used, with CE marking, and a dose of 20 Hertz (Hz) - 200 microseconds (μs) will be applied.

As the control group and the intervention group, the pelvic floor rehabilitator will program the neurostimulator for each case and then they will be trained on how to perform the neurostimulation.

The first session will be carried out with the rehabilitator to learn how it works and resolve doubts about its use, and later the sessions will be carried out at home.

In both groups, a program for carrying out sessions will be indicated according to the following scheme:

• From the 1st month to the 3rd month post-surgery: stimulation 3 times a week
• From the 4th month to the 6th month post-surgery: stimulation 2 times a week
• From the 7th to the 12th month post-surgery: 1 time a week

假比较器：Control group

Posterior tibial nerve stimulation with Beurer EM-49 digital neuroestimulator at subtherapeutic doses

设备：Control group

In the intervention group, Beurer EM-49 digital neurostimulator will be used, with CE marking; and a dose of 80 Hertz (Hz) - 150 microseconds (μs) will be applied.

As the control group and the intervention group, the pelvic floor rehabilitator will program the neurostimulator for each case and then they will be trained on how to perform the neurostimulation.

In order to apply the therapy, the patient must sit down for the placement of the electrodes.

It will be performed on 2 feet at the same time. The first session will be carried out with the rehabilitator to learn how it works and resolve doubts about its use, and later the sessions will be carried out at home.

In both groups, a program for carrying out sessions will be indicated according to the following scheme:

• From the 1st month to the 3rd month post-surgery: stimulation 3 times a week
• From the 4th month to the 6th month post-surgery: stimulation 2 times a week
• From the 7th to the 12th month post-surgery: 1 time a week

Faecal incontinence (FI) - LARS 1st month

Assessed by LARS questionnaire Low anterior resection syndrome (LARS): LARS scale consists of 5 questions: gas incontinence (0,4,7 points), liquid incontinence (0,3,3 points), stool frequency (4,2,0,5 points), defecation fractionation (0,9,11 points) and defecatory urgency (0, 11,16 points). The score range is between 0 and 42 points. Patients are categorized into three groups: no LARS (0 to 20 points), mild LARS (21 to 29 points) and severe LARS (30 to 42 points).

Faecal incontinence (FI) - LARS 6th month

Assessed by LARS questionnaire Low anterior resection syndrome (LARS): LARS scale consists of 5 questions: gas incontinence (0,4,7 points), liquid incontinence (0,3,3 points), stool frequency (4,2,0,5 points), defecation fractionation (0,9,11 points) and defecatory urgency (0, 11,16 points). The score range is between 0 and 42 points. Patients are categorized into three groups: no LARS (0 to 20 points), mild LARS (21 to 29 points) and severe LARS (30 to 42 points).

Faecal incontinence (FI) - LARS 12th month

Assessed by LARS questionnaire Low anterior resection syndrome (LARS): LARS scale consists of 5 questions: gas incontinence (0,4,7 points), liquid incontinence (0,3,3 points), stool frequency (4,2,0,5 points), defecation fractionation (0,9,11 points) and defecatory urgency (0, 11,16 points). The score range is between 0 and 42 points. Patients are categorized into three groups: no LARS (0 to 20 points), mild LARS (21 to 29 points) and severe LARS (30 to 42 points).

Feacal incontinence (FI) - Wexner 1st month

Assessed by Wexner questionnaire. Wexner scale consists of 5 questions (range 0-4): incontinence of solid stools, incontinence of liquid stools, incontinence of gases, use of pads or diapers and alteration of social life. Depending on the frequency, a score of 0 to 4 is assigned. The score can range from 0 to 20 points, considering no incontinence as 0 to 2 points, mild incontinence as a result of 3 to 6 points, moderate incontinence as 7 to 11 points and severe incontinence as a result greater than or equal to 12 points.

Faecal incontinence (FI) - Wexner 6th month

Assessed by Wexner questionnaire. Wexner scale consists of 5 questions (range 0-4): incontinence of solid stools, incontinence of liquid stools, incontinence of gases, use of pads or diapers and alteration of social life. Depending on the frequency, a score of 0 to 4 is assigned. The score can range from 0 to 20 points, considering no incontinence as 0 to 2 points, mild incontinence as a result of 3 to 6 points, moderate incontinence as 7 to 11 points and severe incontinence as a result greater than or equal to 12 points.

Faecal incontinece (FI) - Wexner 12th month

Assessed by Wexner questionnaire. Wexner scale consists of 5 questions (range 0-4): incontinence of solid stools, incontinence of liquid stools, incontinence of gases, use of pads or diapers and alteration of social life. Depending on the frequency, a score of 0 to 4 is assigned. The score can range from 0 to 20 points, considering no incontinence as 0 to 2 points, mild incontinence as a result of 3 to 6 points, moderate incontinence as 7 to 11 points and severe incontinence as a result greater than or equal to 12 points.

Sexual impairment 1st month

Assessed by QLQ-CR38 questionnaire (question 17-18 for both sexes, 20-21 for men and 22-23 for women).

Each question can be answered from 1 to 4 points. And then is it calculated in the sexual impairment analysis (symptoms area)

Sexual impairment - 6th month

Assessed by QLQ-CR38 questionnaire (question 17-18 for both sexes, 20-21 for men and 22-23 for women). Each question can be answered from 1 to 4 points. And then is it calculated in the sexual impairment analysis (symptoms area)

Sexual impairment - 12th month

Assessed by QLQ-CR38 questionnaire (question 17-18 for both sexes, 20-21 for men and 22-23 for women). Each question can be answered from 1 to 4 points. And then is it calculated in the sexual impairment analysis (symptoms area)

Quality of life (QoL) - FIQLS 1st month

Assessed by:

-Fecal Incontinence Quality of Life Scale(FIQLS):composed of 29 items that evaluate 4 health dimensions:lifestyle(10 items),behavior(9 items),depression/self-esteem(7 items) and shame(3 items).Each item has a range from 1 to 5,with 1 being the minimum value for the quality of life state.

Quality of life (QoL) - FIQLS 6th month

Assessed by:

-Fecal Incontinence Quality of Life Scale(FIQLS):composed of 29 items that evaluate 4 health dimensions:lifestyle(10 items),behavior(9 items),depression/self-esteem(7 items) and shame(3 items).Each item has a range from 1 to 5,with 1 being the minimum value for the quality of life state

Quality of life (QoL) - FIQLS 12th month

Assessed by:

-Fecal Incontinence Quality of Life Scale(FIQLS):composed of 29 items that evaluate 4 health dimensions:lifestyle(10 items),behavior(9 items),depression/self-esteem(7 items) and shame(3 items).Each item has a range from 1 to 5,with 1 being the minimum value for the quality of life state

Quality of life (QoL) - QLQ-CR 38 1st month

Assessed by:

-Colorectal Cancer Quality of Life Questionnaire(QLQ-CR38):organized into 2 areas: 1.Functioning area,which includes the body image and sexual functioning scales and the items on enjoying sex and worrying about the future.2.Symptom area with scales for problems with urination,gastrointestinal symptoms,chemotherapy side effects,problems with defecation,problems with the stoma,sexual problems in men and women,and the weight loss item. All scores ranged 1 to 4, and then are lineal transformation is done (0 to 100). In the functioning area,a higher score indicates a better quality of life,while in the symptom area, a higher score indicates a worse quality

Quality of life (QoL) - QLQ-CR38 6th month

Assessed by:

-Colorectal Cancer Quality of Life Questionnaire(QLQ-CR38):organized into 2 areas: 1.Functioning area,which includes the body image and sexual functioning scales and the items on enjoying sex and worrying about the future.2.Symptom area with scales for problems with urination,gastrointestinal symptoms,chemotherapy side effects,problems with defecation,problems with the stoma,sexual problems in men and women,and the weight loss item. All scores ranged 1 to 4, and then are lineal transformation is done (0 to 100). In the functioning area,a higher score indicates a better quality of life,while in the symptom area, a higher score indicates a worse quality

Quality of life (QoL) - QLQ-CR38 12th month

Assessed by:

-Colorectal Cancer Quality of Life Questionnaire(QLQ-CR38):organized into 2 areas: 1.Functioning area,which includes the body image and sexual functioning scales and the items on enjoying sex and worrying about the future.2.Symptom area with scales for problems with urination,gastrointestinal symptoms,chemotherapy side effects,problems with defecation,problems with the stoma,sexual problems in men and women,and the weight loss item. All scores ranged 1 to 4, and then are lineal transformation is done (0 to 100). In the functioning area,a higher score indicates a better quality of life,while in the symptom area, a higher score indicates a worse quality

Patient global impression of improvement (PGI-I)

Assessed by PGI-I questionnaire.

The Patient Global Improvement Visual Analogue Scale (PGI-I) will be used to allow patients to comparatively assess their degree of global improvement after undergoing posterior tibial nerve stimulation therapy. The scale in question has only one question that asks the patient to classify the degree of symptom relief obtained with the treatment according to the 7-point Likert scale. The higher the score, the better the perception of quality of life.

Patient's characteristics

Age at diagnosis (years), sex (man/woman), height (m), weight (kg), BMI (kg/m2), prior anorectal disease (yes and not, if yes should specify)

Concomitant medication for stool

methylcellulose, loperamide, ... (yes or no, if yes should specify)

Tumor characteristics

Date of diagnosis (exact day), clinical TNM stage (TNM), tumour height from the anal verge by colonoscopy (cm) and proctoscopy (cm) magnetic resonance imaging findings (TNM, cm to anal verge), neadjuvant treatment (yes or no, which type), CEA values (ng/mL), neutrophil and lymphocyte values pre and post-chemotherapy (absolut value x10e9)

Surgical details

Date of surgery, surgical approach (laparoscopic (LAP), robotic (ROB), LAP + transanal (TaTME), ROB + TaTME), transanal extraction of the specimen (yes or no), intraoperative complications (specify), type of anastomosis (mechanic, manual), height of anastomosis (cm), protective ileostomy (yes or no)

Follow-up

Days of hospital stay (days), days until intake (days), postoperative complications (yes or no, if yes specify and complete Clavien-Dindo clasification), treatment of postoperative complication (need of new surgery, yes or no, if yes specify surgical procedure), readmission (yes or no, specify why)

Esphinteric funcionality

Rectal examination with basal tone and transperineal ultrasound (normal, insufficient expulsive maneuver, sphincter defect, anism, rectal hypersensitivity, rectal hyposensitivity, not performed), Oxford classification of esphinteric muscular strenght (0 to 5, being 5 good function).

Compliance diary

Registration of the sessions done and observations