The Odstock Dropped Foot Stimulator (ODFS®) has been the subject of 3 randomised controlled trials and several case series studies examining its use in clinical service. Many of the research reports and abstracts are available in the knowledge base. For a detailed summary please click here.
Randomised Controlled Trials (RCTs)
The first RCT was with a group of 32 people who had had a stroke for more than 1 year. Of the 32, 16 people received the device. Both groups had 10 sessions of physiotherapy. The trial lasted 3 months. The main outcomes showed that participants:
- walked 16% faster with ODFS
- walked with a reduction of effort, as measured by the physiological cost index, by 29%
- showed a reduction in quadriceps spasticity
- showed a reduction in anxiety and depression
- indicated a significant positive cost/benefit from the treatment as measured by QALY analysis (Quality Adjusted Life Years)
The trial results together with case series data from subjects who had MS were presented to the South and West Regional Health Authority Development and Evaluation Committee. This process led to the ODFS® being recommended for use in the UK's National Health Service for patients with upper motor neurone lesions.
The second RCT took place with people who had had a stroke less than one year previously and this time looked at the effect of using botulinum toxin to reduce calf spasticity in combination with the ODFS®. 21 participants took part, with both groups receiving physiotherapy intervention. After three months it was shown that the treatment group increased their walking speed faster than the control group.
The third RCT was with people who had MS. 56 participants either received the ODFS® or received Physiotherapy. Again it was shown that the participants walked faster when the ODFS® was used and also that they could walk further in 3 minutes. It was also shown that the ODFS® lead to an improvement in activities in daily living that was not seen in the control group. Finally, the ODFS® group experienced 72% fewer falls than the control group in the 18 weeks of the trial period.
Clinical Service Audit
An audit of clinical service over the first 18 weeks of use confirmed the results of the original RCT and also showed a significant training effect i.e. an improvement in walking ability when not using the stimulator, in a group of 111 stroke subjects.
Overall, users walked 27% faster when they used the device with a training effect of 14%. In a subgroup of 27 ODFS® users walking speed both with and without the device was observed to improve over the first 18 weeks and thereafter remain unchanged. As the ODFS® users were an average of 5.4 (sd +/- 10.7) years post stroke, this supports the hypothesis that the training effect observed was due to the use of the stimulator rather than natural recovery following the stroke. In a group of 78 MS subjects, users walked 20% faster when using the device. In a subgroup of 20 MS users, this improved walking speed with the device was shown to also peak at 18 weeks with no significant change from initial values after that time, indicating the ODFS® is an effective orthotic device.
In a further case series of 21 people who had had a stroke and 20 who had MS, a significant improvement in quality of life was seen after 18 weeks, measures using the Psychosocial Impact of Assistive Devices Scale (PIADS). Questionnaire surveys have shown the main reason people chose to use the ODFS® is that:
|- Increased confidence while walking||78.5%|
|- Reduced effort of walking||77.6%|
|- Increased walking distance||70.1%|
|- Reduced risk of tripping while walking||69.2%|
|- Increased walking speed||61.7%|
|- Increased independence||51.4%|
In 2009 The Interventional Procedure Guidelines IPG278 were published by the National Institute for health and Clinical Excellence (NICE) recommending its use in the NHS. The guidelines states:
1.1 Current evidence on the safety and efficacy (in terms of improving gait) of functional electrical stimulation (FES) for drop foot of central neurological origin appears adequate to support the use of this procedure provided that normal arrangements are in place for clinical governance, consent and audit
The public information document that accompanies IPG278 summarises the guidelines as follows:
This procedure can be offered routinely as a treatment option for people with drop foot caused by damage to the brain or spinal cord, provided that doctors are sure that:
• the patient understands what is involved and agrees to the treatment and the results of the procedure are monitored.
NICE have also published a Medtech Innovation Briefing (MIB) on the ODFS Pace (XL) MIB56, which summarises the evidence and clinical implementation of the ODFS devices.
The NHS Purchasing and Supplies Agency have produced three reports on Functional Electrical Stimulation for Dropped Foot of Central Neurological Origin. The first report CEP10010 Buyers Guide describes the technique and reviews the clinical results. The Second report CEP10011 Market Review describes the devices available on the UK market. The Third report CEP10012 Economic Review describes a cost benefit model for the technique and demonstrates that the ODFS® is cost effective for the NHS.