Foot Drop

What is a Foot drop?

Foot drop (also known as drop foot) refers to an abnormal gait activity in which the dropping of your foot and toes will occur. This condition happens due to the muscular weakness of ankle and toes dorsiflexion or paralysis in the anterior portion of the lower leg. The muscles of the foot and ankle include the anterior tibialis, the extensor hallucis longus, and the extensor digitorum longus ¹.

Specialists typically do not consider foot drop a disease, but a symptom of a more serious problem such as a hidden neurological, muscular, or anatomical problem. Patients with foot drop may not able to lift their foot from the ankle. While walking, this results in dragging the front of the foot on the ground. The duration of foot drop may be temporary or permanent, depending on the severity of the condition.

The causes of foot drop include peripheral nerve injury, neuropathy, muscular dystrophy, certain brain or spinal cord disorders such as amyotrophic lateral sclerosis (ALS), multiple sclerosis, stroke, cerebral palsy, etc. One behavioral cause of foot drop includes the habitual crossing of the legs. Patients with this case will resolve their condition by the discontinuance of their habit. Usually, these cause result in foot drop in one foot, but sometimes this condition may occur in both feet.

The risk factors of this condition comprise the habitual crossing of the legs along with the prolonged kneeling and wearing a leg cast. The habitual crossing of the legs may compress the peroneal nerve on their uppermost leg and the leg cast encloses the ankle just below the knee to put pressure on the peroneal nerve and results in foot drop.

How do neurosurgeons diagnosis Foot Drop?

A significant national online survey reveals that about 17% of US respondents become familiar with foot drop, which can arise from many conditions. About 8.1% of people develop foot drop because of lumbar degenerative disease that affects the respected nerve ².

The initial diagnosis of foot drop includes a routine physical examination performed by a medical professional such as a physiatrist, neurologist, or orthopedic surgeon. This documentation includes the deformity of the patient and neurologic examination to test muscle sensation and strength. The mobility of the leg measures on a scale of 0 to 5. The lowest point, 0, will cause complete paralysis, and the highest point, 5, will show complete mobility.

Doctors may further confirm by many other tests to determine the underlying cause for the diagnosis. Such tests may include imaging tests like X-ray, Ultrasound, CT scan, Magnetic resonance imaging (MRI), Magnetic resonance neurography (MRN), and nerve test like Electromyography (EMG) to assess the damaged nerves and their surrounding areas ³.

How do neurosurgeons treat Foot Drop?

The treatment of foot drop depends according to the cause. Successful treatment of the cause will improve the condition. The treatment protocol may include ^4,5:

1. Wearing braces or splints: A brace or splint will help to stabilize your foot in a normal position and improve your walking.
2. Physical therapy: Regular exercises will help to strengthen your leg muscles and support your knee and ankle to maintain the range of motion. Stretching exercises particularly prevent the stiffness in the heel.
3. Nerve stimulation: Functional electrical stimulation (FES) uses electrical currents to activate nerves extremities that lift the foot improves foot drop.
4. Surgery: For long-term foot drop cases, surgery may necessary. The procedure involves transferring of a working tendon from the stronger leg muscles to the affected muscle that will help to pull your ankle upward. Another surgical option includes fusing of the foot or ankle bones to stabilize the ankle.

If the foot drop is the direct result of a nerve root impingement in the lumbar spine, the neurosurgeon may recommend decompressive laminectomy. The prognosis of foot drop may vary according to the cause of the foot drop. In the case of peripheral compressive neuropathy, it takes up to 3 months for a full recovery. A partial peroneal nerve palsy also results in a good prognosis.

References

1. Gil-Castillo J, Alnajjar F, Koutsou A, Torricelli D, Moreno JC. Advances in neuroprosthetic management of foot drop: A review. Journal of NeuroEngineering and Rehabilitation. 2020;17(1):1–19. doi:10.1186/s12984-020-00668-4
2. Carolus AE, Becker M, Cuny J, Smektala R, Schmieder K, Brenke C. The interdisciplinary management of foot drop. Deutsches Arzteblatt International. 2019;116(20):347–354. doi:10.3238/arztebl.2019.0347
3. Liu K, Zhu W, Shi J, Jia L, Shi G, Wang Y, Liu N. Foot drop caused by lumbar degenerative disease: Clinical features, prognostic factors of surgical outcome and clinical stage. PLoS ONE. 2013;8(11):1–6. doi:10.1371/journal.pone.0080375
4. Nath RK, Lyons AB, Paizi M. Successful management of foot drop by nerve transfers to the deep peroneal nerve. Journal of Reconstructive Microsurgery. 2008;24(6):419–427. doi:10.1055/s-0028-1082894
5. Aldemir C, Duygun F. New and unusual causes of foot drop. Medicine Science | International Medical Journal. 2017;(January):1. doi:10.5455/medscience.2017.06.8602