What is peroneal nerve palsy?

Common peroneal nerve palsy is a condition usually characterized by loss of movement or sensation in the foot and leg. In some cases, the condition may lead to severe disability and often manifests as foot drop or paresthesia.

What is the peroneal nerve?

The peroneal nerve conducts movement and sensation to the lower leg, foot and toes. The peroneal nerve takes origin from the sciatic nerve in the posterior aspect of the upper leg and travels around the head of the fibula bone at the fibula neck, just below the knee. The nerve divides into a superficial and a deep branch. The deep branch supplies the anterior compartment of the lower leg and the muscles that flex the foot. The superficial branch becomes a sensory branch supplying the top of the foot.

Foot drop and the peroneal nerve. Peroneal nerve palsy is capable of affecting people of any age and can result in significant disability — among them dropfoot. With the condition, there is loss of ability to lift the foot and toes (dorsiflexion), as well as loss of the ability to evert the foot. Those with the condition usually find it difficult to walk and, when attempting to do so, drag the foot on the ground when bringing it forward. There is typically loss of muscle control, muscle tone, and, eventually, muscle mass because of lack of effective nerve stimulation to the muscles.

Symptoms of peroneal nerve palsy:

• Foot drop (unable to lift or hold foot horizontal)
• Toes drag while walking
• Weakness of the ankles or feet
• "Foot slap” (walking pattern)
• Walking abnormalities
• Decreased sensation , numbness or tingling at the top of the foot

Information for the medical community

The WalkAide should benefit patients with peroneal nerve palsy caused by stroke, multiple sclerosis (MS), and incomplete spinal cord injury. The WalkAide may not help patients with peroneal nerve palsy as a result of lower motor neuron or peripheral nerve trauma. For example, trauma due to surgery, severed nerve, low back/disc injury or some peripheral neuropathy.

Examination of the legs may show a loss of muscle control over the legs and feet. The foot or leg muscles may atrophy (lose mass). There is difficulty with dorsiflexion (lifting up the foot and toes) and with eversion (toe-out movements).

Tests of nerve activity include:

• EMG (a test of electrical activity in muscles)
• Nerve conduction tests
• MRI to look for compressive lesion along nerve

Other tests are guided by the suspected cause of the nerve dysfunction, as suggested by the person's history, symptoms, and pattern of symptom development. They may include various blood tests, x-rays, scans, or other tests and procedures.

Treatment of drop foot resulting from peroneal nerve dysfunction using the WalkAide is aimed at maximizing mobility and independence. The WalkAide produces dorsiflexion of the ankle during the swing phase of a gait. This small device attaches to the leg, just below the knee, near the head of the fibula. During a gait cycle, the WalkAide stimulates the common peroneal nerve, which innervates the tibialis anterior and other muscles that produce dorsiflexion of the ankle. Users of the WalkAide are people who have lost the ability to voluntarily lift their foot, often as a result of damage to the central nervous system such as stroke, incomplete spinal cord injury, traumatic brain injury, cerebral palsy and multiple sclerosis. This type of stimulation will not work with people who have damage to the lower motor neurons/peripheral nerves.

Information for Users

The WalkAide System is an external functional electrical stimulation system that is intended to address foot drop in people who have sustained damage to upper motor neurons or pathways from the brain to the spinal cord. During the swing phase of walking, the WalkAide electrically stimulates the appropriate muscles that cause ankle dorsiflexion. This results in a smoother, more natural, and safer stepping motion.

Learn more about how WalkAide can positively benefit people experiencing drop foot.