Anatomy Not Precisely Described
We welcome the article by Carolus et al. (1) on the management of foot drop, as it discusses a key interdisciplinary topic. However, it is of clinical importance to distinguish the central elements from the peripheral elements of the neuronal circuitry in a way that is anatomically correct. For the purpose of simplification, the motor system is described as consisting of an upper (central) and a lower (peripheral) neuron. The cell body of the upper neuron is located in the primary motor cortex and its axon extends in the pyramidal tract down to the anterior horn cells of the spinal cord, i.e. the lower neuron. Contrary to the description in the article, this lower neuron is not part of the pyramidal tract. Even though the cell body (perikaryon) of the motor anterior horn cell is, in fact, located in the spinal cord, i.e. in a strict sense within the central nervous system, isolated failure of this second neuron—regardless of the location—results in a typical peripheral (i.e. flaccid) paresis.
With regard to central foot drop, it should be mentioned that electronic foot drop orthoses have now been available for several years (2). The technique of functional electrical stimulation (FES) is used to stimulate the common fibular nerve (peroneal nerve) (3), which is intact in patients with central paresis. The FES technique uses sensors to detect the need for lifting the foot while walking. Unfortunately, the costs for such a system are frequently not reimbursed by health insurances and often a major effort has to be made—e.g. by video documentation of the beneficial effect during testing of the device—to persuade the patient’s insurance to cover the costs.
Finally, we would like to point out that rapid significant weight loss represents a relevant risk factor for the development of (frequently bilateral) common fibular nerve lesions with foot drop.
Prof. Dr. med. Andreas Winkelmann
Institut für Anatomie, Medizinische Hochschule Brandenburg, Brandenburg, Germany
Prof. Dr. med. Andreas Bitsch
Klinik für Neurologie, Ruppiner Kliniken GmbH, Hochschulklinikum der Medizinischen Hochschule Brandenburg, Brandenburg, Germany
|1.||Carolus AE, Becker M, Cuny J, Smektala R, Schmieder K, Brenke C: The interdisciplinary management of foot drop. Dtsch Arztebl Int 2019; 116: 347–54 VOLLTEXT|
|2.||Kluding PM, Dunning K, O’Dell MW, et al.: Foot drop stimulation versus ankle foot orthosis after stroke—30-week outcomes. Stroke 2013; 44: 1660–9 CrossRef MEDLINE|
|3.||Federal Committee on Anatomical Terminology: Terminologia Anatomica, Stuttgart: Thieme 1998.|