Magnetic stimulation of rectal nerves could help treat fecal incontinence

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An ongoing study by the Medical College of Georgia on the role of magnetic stimulation of the rectal nerves to achieve better bowel control in patients with fecal incontinence is showing early promise. The technique is called translumbosacral neuromodulation therapy, or TNT.

 

What is TNT?

 

TNT is a method that uses magnetic stimulation to strengthen and heal the nerve plexus that enables bowel control. Transcranial magnetic stimulation is already being used to treat depression via its action on the nerves. The current trial tests the effect of magnetism on the nerves of the rectum and anus.

 

The magnet produces energy that is converted to electrical energy, stimulating the damaged or weak nerves. These then conduct the impulse to the muscles supplied by them, in this case, the anal musculature, causing them to contract firmly and keep the stool from leaking. This ability is called neuroplasticity: the ability of nerves to heal, reform connections with other nerves, grow back and connect more firmly with the innervated muscle.

 

The study will help to find out if magnetic treatment will help restore connections between damaged nerves from the spinal cord and brain to the gut musculature. If so, this could help to resolve fecal incontinence or lack of bowel control.

 

Fecal incontinence

 

Fecal incontinence is a condition in which stool leaks from the bowel without much warning. This embarrassing condition can cause extreme distress, anxiety, depression, social withdrawal, and poor quality of life. In addition, it may lead to a higher death rate in older people. About half of older people in nursing homes suffer from this condition, according to researcher Satish S. C. Rao, a specialist on the nervous system of the gut.

 

Fecal incontinence is common in America, affecting about 40 million people. It is a problem for 1 in 3 people who approach a primary care provider. Women and elderly people over 65 years are at higher risk because of childbirth-associated trauma, in one, and loss of muscular strength, in the other. Other risk factors include a sedentary life, chronic medical problems like irritable bowel syndrome or diabetes, smoking, and post-cholecystectomy (gall bladder removal). Half the patients will also have urinary incontinence as well.

 

Medical equipment for magnetic stimulation and physiotherapy. Image Credit: nikolay_artjuhoff / Shutterstock

 

How is fecal incontinence treated at present?

 

Therapy for fecal incontinence is lacking, especially when it comes to effective and noninvasive treatments. Many doctors advise diet modification, which is not an effective remedy. Medications and pelvic muscle strengthening are other common suggestions that do not really work well to relieve this debilitating condition.

 

Many current therapies try to increase muscle strength or to surgically repair the torn muscles. Invasive sacral nerve stimulation requires to be done in the operating theatre under anesthesia. Some techniques use implants, which will later need to be removed.

 

On the other hand, Rao thinks most of the problem lies with the nerve damage, which leads in turn to fecal incontinence. One such example is a childbirth-associated injury to the pelvic floor and the anal muscles. These injuries are promptly sutured, in most cases. However, says Rao, the nerve injuries aren’t resolved.

 

The pilot study

 

One reason for the poor success of many methods is the absence of a method that can provide an evaluation of nerve function with ease, accuracy, and impartiality. Current methods can be invasive or painful, such as inserting needle electrodes into the anal muscle.

 

The first step was to bring out a noninvasive method of testing and stimulation that could yield the maximum information without unduly bothering the patient. It centers on a rectal probe with an external coil on the back to generate magnetic fields. This can stimulate the targeted nerves and record the response. Rao calls his novel system translumbosacral anorectal magnetic stimulation test or TAMS.

 

A pilot study was conducted, including patients with fecal incontinence treated with this device. They found that 70% to 80% of patients had stool leakage due to neuropathy of rectal or anal nerves. About 90% of patients showed improvement in muscle function with the low frequency at 1 hertz. Even without doing anal muscle strengthening exercises, they felt the muscle function was better and had a greater sensation that they were about to pass stool.

 

These are very significant steps forward in that they restore some degree of muscle and sensory control to the patients, allowing them to live more normally than always taking care to be in the vicinity of a bathroom.

 

Side effects were minor; the only reported one being transient tingling in the treated area, which could be because of nerve reactivation.

 

The current study

 

Since the presence of nerve injury was a proven issue, Rao et al. moved on to a more extensive study, which is currently underway. The current study will attempt to identify the best dosage of stimulation, evaluate the treatment for safety and effectiveness, as well as to find out the mechanism of action.

 

They are now using magnets to stimulate specific nerves in the back to try and treat the weak nerves. They are also examining how various frequencies would work. From earlier research, they knew higher frequencies would work better on the brain.

 

The study involves 132 patients in two groups, with 44 participants in the control group that received sham magnetic stimulation, and 88 patients in the treatment group. All patients will have had fecal incontinence severe enough to be symptomatic for 6 months, with at least one episode per week. Those with known nerve problems such as head injury, spinal cord damage, or inflamed piles, are not eligible.

 

All patients will be evaluated for gut and brain function, have TAMS testing, and pressure measurements in the anus and rectum (manometry) for a baseline record. These will be repeated after the course of treatment. Nerve function and stool control will also be assessed via a daily electronic stool diary to record normal and incontinent stool passage.

 

The TNT sessions are given once a week for six weeks to the 88 patients in the treatment group. The dose is either 2,400 or 3,600 magnetic stimulations, given at one stimulation per second. The sham therapy, which looks and sounds like the original, is given to the control group.

 

The hypothesis is that magnetic stimulation restores the original connection between the nerves and the muscles. The investigators think they have evidence that this connection is re-established by magnetic stimulation, especially at the dosage of 3600 cycles,. Urinary incontinence due to weakness of the pelvic floor muscles may also benefit from this, says Rao. These muscles are at the base of the abdomen, and their action is central to both containing and releasing feces and urine. Other potential beneficiaries of TNT include those with fecal and/or urinary incontinence secondary to spinal cord injury or neurological disorders like Parkinson’s disease.

 

The researchers will look for improvement by 50% or more in the number of stool leakages. Other secondary outcomes will include firmer stool consistency, smaller amounts of leakage, re-appearance of rectal sensation, and a better quality of life. In addition, they will analyze the function of the nerves, as well as the gut-brain interactions.

 

They are also investigating whether reinforcement therapy will help, in order to see how long the effects will last. The treated patients will be assessed again after 12, 24, and 48 weeks. This will help to rule out the placebo effect and evaluate the actual contribution of the magnetic therapy itself to the improvement in fecal incontinence.

 

The researchers hope that the subgroup, which shows the most significant benefit from TNT will be the treated group, and especially those who receive a higher dose, as well as a treatment after the trial is over. If this is proved, they will move on to a large-scale multicentre clinical trial. Simultaneously, Rao will carry out a direct comparison of three approved treatments already in use for this condition, with respect to their costs, benefits, and side effects.

 

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