Walking
Odstock Medical has a range of treatments to help walking for people with neurological problems such as stroke, MS and Spinal Cord Injury. Our flexible and holistic approach allows us to treat the broadest range of problems and provide appropriate solutions as neurological conditions change. Our experienced staff and comprehensive clinical training courses enable us to provide bespoke FES solutions for each individual.
For further information please click here.
Dropped foot – external electrodes
The most common application of FES is for correction of dropped foot. Dropped foot is the inability to lift the foot as it is brought forward and often causes an unstable ankle when weight is brought back on to the foot. Dropped foot increases the risk of falls, reduces the efficiency of walking, the distance that can be achieved and can significantly affect day-to-day mobility.
FES can be used to lift the foot in walking. Self-adhesive skin electrodes are placed over a nerve called the common peroneal nerve. Small electrical impulses applied to the electrodes elicit nerve impulses that pass down the nerve to the muscle causing it to contract. Stimulation timing is controlled by a pressure sensitive foot switch placed under the heel. Stimulation starts after the heel is lifted from the ground and continues till just after weight returns to the heel, lowering the foot to the ground in a controlled manner. Walking is made safer, faster and more efficient.
STIMuSTEP
Implanted Dropped Foot Stimulator UK
OML are the distributor for Finetech Medical Ltd
The STIMuSTEP is an implanted neuromuscular stimulator intended for the correction of dropped foot following an upper motor neuron lesion. While providing the same function as the ODFS, the device removes the need to accurately place electrodes each day, reduces the sensation of the stimulation and improves the convenience for the user. The rise and fall of the stimulation can be adjusted to prevent a sudden contraction that might induce a stretch reflex of the calf muscles. There are also facilities to add an extension to the stimulation envelope after heel strike, mimicking the natural activity of the anterior tibialis muscle, which contracts eccentrically to lower the foot to the ground and stabilises the ankle at initial contact.
The device stimulates the two branches of the common peroneal nerve using electrodes inserted into the epineurium of each nerve. The deep branch supplies the tibialis anterior (TA), extensor hallucis longus (EHL) and peroneus tertius (PT) muscles. These muscles produce dorsiflexion with weak inversion. The superficial branch supplies the peroneus longus/brevis (PL, PB). These muscles produce eversion and weak plantarflexion. By carefully controlling the stimulation to each nerve, a movement of dorsiflexion with eversion can be achieved.
The device is powered and controlled using close coupled telemetry from a transmitter box worn directly over the implant. Stimulation begins at heel rise and continues until heel strike, controlled using a heel switch. The STIMuSTEP is implanted under general anaesthetic in day surgery procedure taking approximately 1 hour.
For more information please click here.
The effect of FES for dropped foot
Whether the ODFS Pace or STIMuSTEP is used the main effects are increased dorsiflexion (foot-lift) and eversion (foot turning out) in the swing phase of gait produces. This leads to:
- Improved ground clearance
- Reduced tripping and falls
- Reduced compensatory activity
- Reduced effort of walking
- Reduced spasticity
- Increased walking speed
- Heel strike with eversion
- improved loading response
- greater stability in stance
- Greater range of mobility
- Greater safety, confidence and independence while walking
- Greater social interaction and improved quality of life
More complex walking problems
O2CHS - Odstock Two Channel Stimulator
The O2CHS is a 2 channel foot switch controlled neuromuscular stimulator designed to assist dropped foot and other gait problems following an upper motor neurone lesion. It has the same facilities as the ODFS Pace with additional features to control the interaction of the two channels. This gives the device great flexibility allowing its application for many different situations. The following table gives some of the commonly used combinations of muscles that are stimulated. In many cases a second muscle group is added to compliment dropped foot correction. If three or more muscle groups are required, the O2CHS can be synchronised with a second O2CHS or an ODFS Pace.
Stimulated muscles /groups | Conditions | Problem addressed |
Bilateral dorsiflexion | MS, FSP and CP | Bilateral dropped foot |
Dorsiflexion with hamstrings | Stroke and MS | Dropped foot with reduced knee flexion |
Dorsiflexion with gluteal muscles | Stroke and MS | Dropped foot with hip flexion / adduction in stance |
Dorsiflexion with quadriceps | Incomplete SCI | Dropped foot with quadriceps weakness |
Dorsiflexion with calf muscles | Stroke, MS, CP etc | Dropped foot and lack of push off in terminal stance |
Dorsiflexion with triceps / deltoid muscles | Stroke. | Dropped foot with strong associated reaction in the upper limb |
Bilateral erector spinae / gluteal muscles | SCI, FSP | Trendelenburg gait |
Bilateral quadriceps | SCI, FSP | Quadriceps weakness |
The timing of muscle activation can be adjusted so that a contraction can occur as weight is transferred on or off a footswitch or set to occur at other times in the gait cycle by adding a delay following a footswitch transition. The device is used as an orthotic aid, replacing conventional splinting and also as a training device assisting gait re-education.
