Advice
The technology
The technology
Axonics sacral neuromodulation (SNM) system (Axonics Modulation Technologies, Inc.) stimulates a sacral nerve root (normally the S3 sacral nerve root) through an implantable pulse generator implanted subcutaneously in the upper buttock. Lead electrodes implanted through the corresponding sacral foramen transmit pulses from the stimulator to the sacral nerves. The stimulator is powered by a rechargeable battery which the company claim has an expected life span of 15 years or more.
A handheld remote control activates the stimulator, adjusts the stimulation amplitude, and checks the battery status. A wireless charger, placed on the skin over the implanted stimulator, is used to charge the stimulator. The company claims that the battery needs recharging every 1 to 2 weeks for 30 minutes to 1 hour. The implanted device is programmed by a clinician in an outpatient setting using a portable tablet.
Before permanent implantation, a temporary trial of SNM is recommended to assess response to therapy. Using the external stimulator, 2 different trial stimulation techniques can be done; a percutaneous nerve evaluation test using the non-tined single-contact temporary lead or a first stage tined lead test using the permanent tined lead. The company also offers kits containing all surgical tools needed for a percutaneous nerve evaluation test and a tined lead implant at extra cost.
Axonics SNM system can be used to treat symptoms of overactive bladder, faecal incontinence and urinary retention. NICE has published medical technologies guidance on the use of Axonics SNM system for treating refractory overactive bladder syndrome. This briefing is focused on the use of Axonics SNM system for treating faecal incontinence only.
Innovations
According to the company, the rechargeable battery that powers the stimulator has an expected lifespan of at least 15 years, which is longer than the comparable non-rechargeable device currently used as standard care. It is designed to reduce the number of invasive battery replacement procedures which would typically be needed around every 5 years with a non-rechargeable system. The stimulator is compatible with MRI and is smaller than existing non-rechargeable SNM devices, making it more suitable for people with a low body mass index.
Current care pathway
Adults with faecal incontinence will usually start treatment with a combination of conservative interventions (including dietary changes, addressing bowel habits, identifying coping strategies and medication) followed by specialist conservative management (such as pelvic floor muscle training, bowel retraining, specialist dietary assessment and management, biofeedback, electrical stimulation and rectal irrigation) if symptoms persist. If faecal incontinence continues after conservative management, specialist assessments may be done to identify possible causes and assess the person's suitability for surgery. Surgical treatments include repairing or tightening the sphincter (sphincteroplasty), or a colostomy (for severe uncontrolled faecal incontinence). Neosphincter surgery (graciloplasty or an artificial anal sphincter) may be considered, although these procedures are now very rarely done in the UK.
The following publications have been identified as relevant to this care pathway:
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NICE's guideline on faecal incontinence in adults recommends that SNM therapy should be considered in people with faecal incontinence in whom sphincter surgery is deemed inappropriate. The guideline states that people should be offered sacral nerve stimulation based on their response to percutaneous nerve evaluation during specialist assessment, which is predictive of therapy success.
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NICE's interventional procedures guidance on sacral nerve stimulation for faecal incontinence suggests that SNM therapy is an option that is typically offered as a surgical treatment for most patients in whom sphincter repair is inappropriate. The guidance also states that the procedure should only be done in specialist units by clinicians with a particular interest in the assessment and treatment of faecal incontinence.
Population, setting and intended user
Axonics SNM system would be used instead of non-rechargeable SNM systems in line with existing guidelines for faecal incontinence. Faecal incontinence is an inability to control bowel movements, resulting in involuntary soiling. It may result from degeneration of the anal sphincter, spinal injury or other neurologic disorders. Faecal incontinence may also happen for no known reason. The condition is associated with a high level of physical and social disability. If left untreated, the person may end up wearing pads to control the condition. It is estimated that up to 1 in 10 people will be affected by faecal incontinence during their lives.
Therapy with Axonics SNM system would be started by secondary care multidisciplinary teams including surgeons, specialist nurses and physiotherapists, and implanted by surgeons specialising in bowel dysfunction. As with other SNM devices, patient selection is guided by a positive response to a trial of tined lead testing or percutaneous nerve evaluation.
After implantation, people with the implant will use the remote control to adjust the level of stimulation depending on symptom control and comfort. They will also recharge the stimulator when battery level is low (as shown by the patient remote control).
Costs
Technology costs
Axonics SNM system, including necessary consumables and accessories, costs £10,635 (excluding VAT) regardless of the type of temporary stimulation used. The cost of replacing the system, which the company estimates is needed at most every 15 years, is £7,000.
A full breakdown of component costs (excluding VAT) are provided below. All Axonics SNM system components are sold with a 12‑month product warranty.
Components for the trial phase (basic evaluation) include:
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a trial lead and surgical tools (contains 1 percutaneous nerve evaluation [PNE] lead and all surgical tools needed for a PNE lead implant) at a cost of £300
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a single-use, disposable external stimulator (1 belt included) at a cost of £175.
Components for permanent implant include:
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a neurostimulator (expected battery life of more than 15 years) at a cost of £7,000
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a tined lead at a cost of £1,600
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a permanent lead implant kit (contains all surgical tools needed for a tined lead implant) at a cost of £500
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a patient remote control at a cost of £500
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a charging system (includes 1 belt and 9 adhesive carriers) at a cost of £560.
The costs associated with a permanent implant assume that the patient had a successful basic trial evaluation.
For an advanced trial evaluation, an additional £2,100 would be needed for the trial phase (trial lead and surgical tools [£300] are replaced with a tined lead with percutaneous extension [£1,900] and lead implant kit [£500]). However, the costs associated with permanent implant in these people would be £2,100 less because the tined lead and permanent lead implant kit would not be needed.
As well as the device costs, the average cost of implantation is £2,772 (average NHS reference costs 2018 to 2019 for HRG codes FF47Z [insertion of neurostimulator] and FF48Z [insertion of neurostimulator electrodes]).
Costs of standard care
A standard non-rechargeable SNM device, including necessary consumables and accessories, costs up to about £10,000 (excluding VAT) depending on the type of temporary stimulation used. The cost of replacing the system, which is typically needed around every 5 years because of battery depletion, is around £6,000. As well as the device costs for standard care, the average cost of implantation is £2,772 (NHS reference costs, 2018 to 2019).
Resource consequences
If adopted, Axonics SNM system would be used instead of a standard non-rechargeable SNM device, without needing changes to the current pathway in which SNM therapy is currently delivered in the UK.
The initial costs of implanting Axonics SNM system are similar to current non-rechargeable systems and, assuming the system needs replacement less often, it could reduce costs for medium- to long-term treatment (more than 5 years).
The company claims the clinician programmer accessory, which consists of a touchscreen colour tablet with built-in stimulation capabilities, provides a superior user experience for the surgeon because it is designed to decrease programming time and the need for manufacturer support.