Stimulating the nerves to fix a leaky bladder or bowel
For years Mr Leong avoided going out for fear of embarrassing himself in public. But after undergoing a little known surgical procedure known as sacral neuromodulation (SNM), he said his life “has been transformed.”
“No more leaking!” said Mr Leong of his urinary incontinence, adding that he now enjoys his retirement in peace.
SNM involves stimulating the third and fourth sacral nerves to help regulate bladder and bowel activity. Although it is little known and isn’t offered widely in this region, SNM is a well-established procedure in the West, having been introduced some 20 years ago to treat urinary incontinence. SNM benefits specific types of urinary incontinence such as overactive bladder (OAB) or having sudden urges to urinate, and those patients whose faecal incontinence is due to anal sphincter muscle weakness or defect, pelvic nerve injury or weakness.
According to Dr Cherylin Fu, Senior Consultant, Department of Colorectal Surgery, Singapore General Hospital (SGH), when the right criteria for SNM is met, “patients can be very effectively treated with up to 76 per cent reduction in their OAB symptoms, and faecal incontinence symptoms reduced by at least half in 70-80 per cent of patients.”
In Singapore, 10-40 per cent of the population is estimated to suffer from some form of urinary incontinence and 4.7 per cent from faecal incontinence. Disorders like pelvic floor weakness or overactive bladder can cause urinary incontinence. Likewise, faecal incontinence may be related to weakness of the anal sphincter muscles, a defect with the nerves innervating these muscles, or pelvic organ prolapse. Faecal incontinence that is caused by an anal muscle or nerve problem can often be addressed successfully with SNM.
SGH began offering the SNM procedure to patients in 2010, although few patients chose to undergo this procedure until more recently. Since 2015, 13 patients have undergone the SNM procedure, including five for urinary incontinence that was due to overactive bladder and/or urinary retention, and eight for faecal incontinence.
Four of the five urinary incontinent patients were able to have the permanent implant, said Dr Tricia Kuo, Consultant, Department of Urology, SGH. They now have better bladder control – one patient stopped using pads altogether, and another is able to sleep for up to four straight hours where previously he could not. Of the patients with faecal incontinence, two underwent permanent implantation. One patient’s bowel frequency and faecal incontinence improved significantly, but the other patient experienced no long-term benefit.
The number of patients who have undergone SNM at SGH may be relatively small, but according to Associate Professor Emile Tan, Head, Department of Colorectal Surgery, and Director of the Gastrointestinal Function Unit, SGH: “The results for faecal incontinence are really quite remarkable. SNM has made significant difference in the quality of life for patients, restoring function and independence.”
Prof Tan, who returned to Singapore after specialising in SNM and pelvic floor diseases in London, treated 120 faecal incontinent patients there. Of the number, 95 underwent the permanent implant – an 80 per cent success rate for treating faecal incontinence, he said.
ANNEX – FAQ
What is sacral neuromodulation?
Sacral Neuromodulation (SNM) or sacral nerve stimulation involves electrical stimulation of the sacral nerves via an implantable neuro stimulator and lead. The electrical stimulation regulates the nerves that supply the bladder, bowels, urinary and anal sphincters, and pelvic floor muscles. The intensity and frequency of the pulses can be modified by both the physician and the patient through an external programmable device.
SNM has been effective in treating faecal incontinence, urinary retention and symptoms of overactive bladder, including urinary incontinence.
Which patients are most likely to benefit from SNM?
Patients likely to benefit from SNM are those whose urinary incontinence is due to an overactive bladder; and those whose faecal incontinence is due to anal sphincter muscle weakness or defect, pelvic nerve injury or weakness. These are usually related to pregnancy and childbirth.
SNM is suitable for certain conditions, and treatment needs to be tailored according to each patient’s profile and medical condition.
How long does the patient need to stay in hospital for an SNM procedure?
Before the stimulator is implanted, the patient needs to undergo an evaluation stage to find out if the treatment is suitable for him. He undergoes a day procedure where a lead wire is inserted into his lower back to stimulate the designated sacral nerves. This is done through a portable stimulator. He wears the wire for three-four weeks, and if found suitable, he undergoes the permanent phase to have the stimulator implanted. For this procedure, the patient is admitted for one-two days.
Are there any risks or side effects?
After implantation, patients may experience pain or bleeding at the site of the wound (13 per cent); electrode dislodgement (displacement or breakage) (5.3 per cent); and infection (3.9 per cent).
What is urinary incontinence?
Urinary incontinence (UI) is any involuntary leakage of urine.
Losing some urine while coughing, sneezing, laughing, exercising or lifting heavy things is called stress urinary incontinence. An increase in pressure on the bladder, together with weak pelvic floor and bladder door muscles (urethral sphincter), can lead to urine leak. Some risk factors include increasing age, post-menopausal women, multiple pregnancies, being overweight and having any medical condition that causes someone to cough/sneeze more often than usual (e.g. asthma, smoker’s cough, chronic lung disease).
Urgency incontinence is the leakage that usually follows a sudden need to pass urine (urgency sensation). This is not exactly the same as overactive bladder as people who suffer from overactive bladder may or may not have urine leakage. If someone with overactive bladder leaks urine, then this can also be called urgency incontinence. Risk factors include neurological disease (e.g. Parkinson’s disease, stroke, multiple sclerosis) and ageing.
Mixed incontinence is where both stress and urgency urinary incontinence exist together. Overflow incontinence is usually associated with bladder outlet obstruction (e.g. an enlarged prostate in men), or failure of the bladder muscle to contract or squeeze appropriately.
Total/continuous incontinence occurs when there is an abnormal connection (fistula) between the bladder and the vagina.
How is urinary incontinence treated?
This depends on the type of incontinence, severity, patient profile and personal preference. For instance, urgency urinary incontinence and overactive bladder can be treated via lifestyle changes such as pelvic floor exercises, consuming less caffeine and alcohol, and medications, minimally invasive options and surgery. Patients can also opt for other less conventional treatments such as botulinum toxin injection and electrical nerve stimulation e.g. sacral neuromodulation, and percutaneous tibial nerve stimulation.
What is faecal incontinence and how is it treated?
Faecal incontinence may be related to weakness of the anal sphincter muscles, a defect with the nerves innervating these muscles, or pelvic floor or organ prolapse.
Treatment depends on the cause and severity of the condition, and can range from the conservative such as lifestyle and dietary modifications, medications, to surgery, such as SNM and sphincter repair or augmentation.
How many patients at SGH have been seen for faecal and urinary incontience?
The SGH Pelvic Floor Disorders Service, a specialised multidisciplinary unit, sees an average of 260 to 300 patients a year. They include those with faecal and urinary incontinence, as well as other pelvic floor conditions such as pelvic organ prolapse.
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