Sacral nerve stimulation for incontinence

In this episode of PodMD, specialist colorectal surgeon Dr Suat Chin Ng will be discussing the topic of sacral nerve stimulation (SNS) for incontinence, including what SNS is, how the procedure is carried out, what are the potential complications, when a GP should refer and more.


  • Transcript
    Please note this is a machine generated transcription and may contain some errors.
    *As always, all in this PODMD podcast is intended for health professionals and the comments are of a general nature. Information given is not intended as specific medical advice pertaining to any given patient. If you have a clinical issue with one of your patients please seek appropriate advice from a colleague with expertise in the area.

    Today I’d like to welcome to the PodMD studio Dr Suat Chin Ng

    Dr. Suat Chin Ng is a specialist colorectal surgeon treating patients in the Eastern suburbs of Melbourne.

    Dr Suat Chin Ng is one of the few female colorectal surgeons in Melbourne who is a member of the Colorectal Surgical Society of Australia and New Zealand (CSSANZ) and member of the Section of Colorectal Surgery of the Royal Australasian College of Surgeons (RACS). She attained her General Surgical Fellowship of the RACS in 2018 and completed a Masters degree in Colorectal Surgery.

    Today, we’ll be discussing the topic of sacral nerve stimulation for incontinence

    *We do hope you enjoy this podcast but please remember that the advice here is of a general nature and is not intended as specific advice about a given patient. The views and opinions expressed in this podcast are those of the doctor, not PodMD.
    If you do have a patient on whom you require specific advice, then please seek advice from a colleague with appropriate expertise in that area.

    Suat Chin, thanks for talking with us on PodMD today.

    Suat Chin: Thank you for having me.

    Question 1
    The topic of today’s discussion is sacral nerve stimulation for incontinence
    Suat Chin, Can you describe for our listeners what sacral nerve stimulation is?

    Suat Chin: Sacral nerve stimulation is an established treatment for faecal incontinence. The prevalence of faecal incontinence has been estimated to be approximately 11% in the Australian population. In women over 45, specifically, the incidence is up to approximately 20% and in nursing home populations the incidence could be as high as 50%. So majority of the faecal incontinence can usually be managed successfully with conservative measures in the community by the GP. But if these measures fail, sacral nerve stimulation, SNS for short can be considered a first line surgical option for faecal incontinence patients with or without sphincter defects. It acts on the anorectal complex at the pelvic afferent level and it also decreases resting in squeeze pressuresand improved rectal sensitivity.

    Question 2
    Why is the incidence of faecal incontinence higher in women?/strong>

    Suat Chin: It’s higher in women because women have babies. And when we are younger before menopause, the oestrogen levels often hides the symptoms of faecal incontinence, the incidence increases as women get older, postmenopausal because of the oestrogen levels, the sphincter function becomes weaker and and that’s where people would start noticing symptoms, or faecal incontinence.

    Question 3
    When is SNS indicated and how is it done/implanted?

    Suat Chin: Sentences indicated mainly in three types of scenario, most commonly when patients with faecal incontinence have failed the conservative measures. And in recent times, the indication of SNS has been expanded to include patients with low anterior resection syndrome, LARS for short. And lastly, for patients with sphincter defects specifically, there has been a paradigm shift to using SNS instead of annual sprinter repair nowadays.

    Typically, S&S is done over two stage approach where patient is able to determine the efficacy and the suitability of the device prior to permanent implantation. A permanent or temporary wires inserted into the S3 foreman. Satisfactory placement is determined by visualisation of anal fallowing and selection of victor on the same side. The wires are then connected to an external device and the settings are adjusted accordingly to reach optimal continence control. Patient is asked to keep a diary of bowel actions and if the incontinence is noted to reduce by approximately 50%, the permanent electrodes are then inserted a week or so later when implanted pulse generator is secured in the subcutaneous pocket in the buttock.

    Question 4
    Are there any Other surgical options of management for FI?

    Suat Chin: Yes, they are. If sphincter defect is present then annual sphincter repair can be considered. But important to note, the effectiveness of the repair in terms of continents can deteriorate over time. PDQ injections can also be considered in these scenarios. Other less established alternatives include vaginal bowel control system, where the vaginal insert is inflated by the patient to physically compress the rectum. And lastly, annual silicone plugs.

    Question 5
    What are the complications of SNS?

    Suat Chin: Well, like any surgery, there are always going to be potential risks. Pain and paresthesia may be reported over the wound or scar area. There is also a small risk of infection and bleeding. But I think what’s most important is the reoperation rate. It’s been reported to be approximately 20% in the literature over long periods of follow up. And the common causes for reoperation include a loss of benefit in approximately 5% of cases. Where the removal of devices ultimately indicated and more commonly in the past, is due to the need of battery replacement.

    Question 6
    Have there been any developments in treatment in the last years or are there any in trials or development now?

    Suat Chin: As we have mentioned before, SMS is sent established modality for faecal incontinence, although it’s a procedure that is less known amongst doctors in the community due to a lack of access to this procedure, especially in the public system. Not all hospitals provide this service. In the last two decades, the potential list of applications for SNS therapy had continued to expand. A recent meta- analysis by Ram ET al. has shown that SMS is beneficial in patients who suffer from LARS. Although most studies in the meta analysis were retrospective in nature, there were also several quality of life studies, showing very good results.

    Well, I guess this is not really surprising as in the past permanent colostomy has been the last result for patients with severe incontinence secondary to LARS . But now SNS can be a welcome alternative. Furthermore, advances in technology will continue to address the current issues and complications that arise with SNS. Wireless battery recharging capabilities for one can reduce the need for the device removal and battery depletion. The newer rechargeable batteries are also smaller, allowing for greater patient comfort, and these new devices are now also MRI compatible and have an expected battery life of approximately 15 years. Instead of the traditional five years only.

    Question 7
    When should a GP refer?

    Suat Chin: Well, I feel. That patients with severe symptoms in general are more appropriate for consideration of more aggressive management, so patients with debilitating faecal incontinence or symptoms of Lars, failing conservative management should definitely be referred.

    Question 8
    How is Faecal incontinence assessed?

    Suat Chin: There’s a lot of validated tools out there that can be used to assess faecal incontinence, faecal incontinence severity index for one, the Saint marks incontinence score, and lastly the Cleveland Clinic Faecal Incontinence score. These tools can be easily accessible online and they can be used in conjunction with the faecal incontinence quality of life scale. LARS, on the other hand, can be assessed using the LARS scoring system, which again is an easy tool to use that you can get from online for assessment of bowel dysfunction, following lower anterior resection for rectal cancer.

    Question 9
    What other investigations are usually needed before SNS implantation?

    Suat Chin: Specialist testing including anorectal, manometry, pudendal nerve latency tests and endoanal ultrasound to assessing the integrity are important tests to facilitate and provide a complete picture of the patient’s condition. And also importantly, before SNS implantation is considered, it is also vital to exclude malignant or premalignant causes for diarrhoea with the colonoscopy.

    Question 10
    What role does the GP play in the treatment of the condition?

    Suat Chin: I feel that the first part of assessment could be performed by the GP by completing history taking and examination and referral to a specialist for consideration of colonoscopy to exclude malignant causes for symptoms of incontinence or diarrhoea. And once the malignant course is excluded, the GP can then trial patients on conservative measures. These measures are such as medication, where you can use stool bulking medication, for example, Metamucil and anti-diarrhoea medications, for example, loperamide may be used and titrated according to the individual patient. Biofeedback technique may also be used for this referral to the pelvic floor physiotherapist would be useful for patients to trial at least three months of biofeedback.

    Concluding Question
    Thank you for your time here today in the PodMD studio. To sum up for us, could you please identify the three key take home messages from today’s podcast on SNS?

    Suat Chin: Firstly, when dealing with patients with faecal incontinence or unexplained diarrhoea, I think it’s important to risk assess the patients and refer them for colonoscopy to exclude malignant causes of faecal incontinence.

    Secondly, the GP control conservative management with medications such as stool bulking agents and anti-diarrhoea medications. The GP can also refer the patients to pelvic floor physiotherapists, for biofeedback therapy and trial this for three months.

    Lastly, for patients with debilitating faecal incontinence, a referral to a specialist colorectal surgeon for consideration of SNS can be made.

    Thanks for your time and the insights you’ve provided.

    Suat Chin: Thank you so much for everyone’s time

*As always, all in this PODMD podcast is intended for health professionals and the comments are of a general nature. Information given is not intended as specific medical advice pertaining to any given patient. If you have a clinical issue with one of your patients please seek appropriate advice from a colleague with expertise in the area.