Current Concepts In Diagnosing And Treating Drop Foot

Start Page: 68

A Guide To Common Foot Drop Etiologies

• Hypothyroidism
• Lymphomas
(Hodgkin’s or non-Hodgkin’s)
• Guillain-Barré Syndrome
• HIV infection
• Cytomegalovirus infection
• Diabetes
• Megaloblastic anemia
• Intracranial tumors
• Brain lesions
• Tumors of the head and neck
• Trauma (direct injury)
• Antineoplastic drugs
• Spinal cord compression
• Direct peripheral
nerve invasion
• Autoimmunity
• Obesity or weight loss
• Idiopathic
• Local tumors such as ganglion or synovial cysts
• Nerve sheath tumors (schwannoma)
• Neurofibroma
• Bone tumors
• Postural (prolonged squatting, sitting or kneeling)
• Prolonged hospitalization
• Bed rest
• Internal surgery
(positioning on table)
• Ankle inversion/sprains
• Orthopedic (fibular fractures)
• Cast immobilization
• Tibial plateau repair/fracture
• Knee arthroplasty
• Hip surgery

Nicholas Romansky, DPM, Kelly Scollon-Grieve, MD, and James G. McGinness, CPO

   When it comes to using electrical stimulation versus an AFO, there are several advantages. First, with functional electrical stimulation, patients have the ability to produce an active contraction that will help to prevent muscle atrophy. Additionally, motor learning and neuroplastic changes in the central nervous system are enhanced by the repetitive active movement that occurs with gait facilitated by functional electrical stimulation.12

   A recent study conducted at the National Institutes of Health further supports the evidence base for using functional electrical stimulation to improve gait.13 The study looked at 19 children with the diagnosis of cerebral palsy ranging in age from 7 to 20. The investigators documented the children’s gait pattern initially after a four-week “training” period and after a three-month treatment period with the WalkAide functional electrical stimulation system.

   The outcomes showed that 95 percent of the kids chose the functional electrical stimulation as the preferred treatment over wearing a brace or not wearing anything.13 The participants wore the unit for an average of 5.7 hours per day and demonstrated improved kinematics including improved dorsiflexion during the swing phase of gait as well as at initial contact. In addition, the use of functional electrical stimulation allowed plantarflexion at toe off during gait, which an AFO typically blocks.

   While functional electrical stimulation is continuing to demonstrate a viable alternative to AFO use for many patients with drop foot, it is not for everyone. Patients with peripheral nerve pathologies such as poliomyelitis, lumbar spinal stenosis, Guillain-Barré syndrome or spinal disc injury are not candidates. In addition, functional electrical stimulation is contraindicated for individuals with pacemakers, defibrillators, fixed plantarflexion contractures or if they have a history of seizure disorder.

   Functional electrical stimulation does little to control knee or ankle stability so one must consider this when evaluating a patient for his or her appropriate needs. One can also consider incorporating the use of a supramalleolar orthosis, a University of California Biomechanics Lab device or custom foot orthoses with the use of functional electrical stimulation. Managing patients with the right combination of treatments typically results in greater success and more patient satisfaction.

   While there are notable contraindications for the use of functional electrical stimulation to improve gait, it can be a viable alternative for many individuals with drop foot. A recent patient who suffered an incomplete T5-T6 spinal cord injury is thrilled to be able to go without the use of a traditional style AFO. She wears her functional electrical stimulation unit 12 to 14 hours a day and is able to independently don and doff the unit. She is also able to wear almost any shoe she wants. When she travels to Florida in the winter, it does not present her with issues of bulk or heat.

   Additionally, we have seen improved gait characteristics such as increased dorsiflexion during swing and at initial contact with functional electrical stimulation.

Key Insights On Surgical Solutions For Drop Foot

The surgical goal is to achieve a stable, well-aligned foot and ankle to leg relationship. Removal of the source of compression is usually necessary if it is a focal compression of the fibular nerve, sciatic nerve, nerve root, or spinal cord or brain tumor.

   Surgical options in the lower extremity include ankle arthrodesis and tendon transfer. Arthrodesis may occur at the ankle joint, Lisfranc’s joint or with a triple/pantalar arthrodesis with or without Achilles tendon lengthening. For symptomatic relief of pain, consider analgesics, neuropathic pain medications and nerve blocks.1,14

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