Condition category
Digestive System
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Prof Norman Williams


Contact details

Centre for Academic Surgery
The Royal London Hospital
Whitechapel Road
E1 1BB
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number

LREC number 06/Q0601/46, protocol dated 25/05/06 v1

Study information

Scientific title

Prospective randomised double-blind placebo-controlled crossover study of sacral nerve stimulation in patients with severe rectal evacuatory dysfunction and rectal hyposensitivity


Study hypothesis

Patients with constipation secondary to a rectal evacuatory disorder and rectal hyposensation will derive symptomatic improvement, with normalisation of rectal sensory thresholds to balloon distension, following sacral nerve stimulation.

Ethics approval

Redbridge and Waltham Forest Local Research Ethics Committee approved on 14th August 2006 (ref: 06/Q0601/46)

Study design

Single centre randomised placebo-controlled double-blind crossover pilot study

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details found in the interventions field below to request a patient information sheet




1. Anorectal physiology: this will take 30 minutes; patients selected for the study will be required to have full anorectal physiology investigations. This will consist of anal manometry, rectal sensory thresholds, pudendal nerve stimulation, endoanal ultrasound, defaecating proctogram and colonic transit study.
2. Implantation of the temporary sacral nerve stimulation wire - this will take up to 60 minutes and can be done under local or general anaesthetic depending on patient choice. Throughout the procedure an image intensifier will be used intermittently to take x-rays, for a total of 2 - 3 minutes.
3. Rectal sensory thresholds - this will take up to 5 minutes; subjects will have rectal sensory thresholds to balloon distension after two weeks, at the crossover period, and at the end of the trial at 4 weeks. This consists of a balloon on the end of a catheter which will be placed into the rectum through the anus. The balloon will be inflated with air and note will be made of the volume required before the subject has the first constant sensation (FCS), a sustained desire to defaecate (DDV) and the maximum volume they can tolerate (MTV).
4. Questionnaires related to quality of life (36-item short form health survey [SF36], Gaol), symptom scores (Wexner constipation scores) will be completed at the end of two weeks and then again at the end of 4 weeks

Intervention is sacral nerve stimulation, each patient has this for 4 weeks in total 2 with stimulation off (ie placebo and therefore the control), 2 weeks with the stimulation on. Neither investigator or patient knows which arm of the trial they are in. The blinding is removed at the end of the 4 weeks.

Contact Details for Patient Information Material:
Chetan Bhan
Specialist Registrar
Academic Surgical Unit
The Royal London Hospital
London E1 1BB

Intervention type



Not Applicable

Drug names

Primary outcome measures

1. Normalisation of rectal sensory thresholds to balloon distension (first constant sensation, defaecatory desire volume, maximum tolerable volume)
2. Improvement in Cleveland Clinic Constipation scores
3. Increase in percentage of complete bowel movements from the bowel diaries

Measured at baseline then after two weeks and then after 4 weeks.

Secondary outcome measures

Improvements in the following criteria during the stimulation period:
1. Quality of life using validated methods of assessing health related quality of life (SF36) and gastrointestinal related quality of life (GIQoL)
2. Data from bowel diaries

Measured at baseline then after two weeks and then after 4 weeks.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Patients aged 18 - 65 years, either sex
2. Incomplete and/or assisted evacuation
3. Idiopathic (no rectal surgery, no spinal and overt neurological history)
4. Failed maximal conventional therapy
5. Normal colonic transit and rectal diameter
6. No significant mechanical obstructive abnormality on proctography
7. Unable to evacuate greater than 60% contrast in 3 minutes
8. Rectal hyposensation (based 2/3 abnormal values of first constant sensation [FCS], defecatory desire [DDV] and maximum tolerable volume [MTV] to balloon distension)

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Inability to provide informed consent
2. Severe concomitant medical conditions precluding randomisation to operative treatment
3. Neurological diseases such as diabetic neuropathy, multiple sclerosis and parkinson's disease
4. Other medical conditions precluding stimulation: e.g. bleeding disorders, certain cardiac pacemakers
5. Congenital anorectal anomalies or absence of native rectum due to surgery
6. Present evidence of external full thickness rectal prolapse
7. Previous rectal surgery (rectopexy/resection) done less than 12 months ago (24 months for cancer)
8. Stoma in situ
9. Chronic bowel disease such as inflammatory bowel disease, chronic uncontrolled diarrhoea
10. Anatomical limitations that would prevent successful placement of electrodes
11. Pregnancy or intention to become pregnant
12. Previous experience of sacral nerve stimulation (SNS)

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Centre for Academic Surgery
E1 1BB
United Kingdom

Sponsor information


Queen Mary, University of London (UK)

Sponsor details

c/o Gerry Leonard
Queen Mary's Innovation Centre
Barts and the London School of Medicine and Dentistry
Joint Research and Development Office
Lower Ground Floor
5 Walden Street
E1 2EF
United Kingdom

Sponsor type




Funder type


Funder name

Barts and the London School of Medicine and Dentistry, Queen Mary University of London (UK) - Colorectal Development Unit, Academic Surgical Unit

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

2012 results in:

Publication citations

  1. Results

    Knowles CH, Thin N, Gill K, Bhan C, Grimmer K, Lunniss PJ, Williams NS, Scott SM, Prospective randomized double-blind study of temporary sacral nerve stimulation in patients with rectal evacuatory dysfunction and rectal hyposensitivity., Ann. Surg., 2012, 255, 4, 643-649, doi: 10.1097/SLA.0b013e318247d49f.

Additional files

Editorial Notes