PILOT STUDY OF COMBINED TRANSVERTEBRAL MAGNETIC AND TRANSCUTANEOUS STIMULATION FOR THE REHABILITATION OF COMBAT ACUTE SPINAL CORD INJURIES

Abstract

Aim of the study: To improve the effectiveness of neurorehabilitation in patients with severe combat spinal cord injury by combining spinal cord repetitive transvertebral magnetic stimulation (rTvMS) and non-invasive transcutaneous electrical stimulation (TcES) of peripheral nerves.

Clinical rationale for study: For the best recovery from severe combat spinal cord injury, neurorehabilitation must start in the acute phase. Only technologies targeting sensorimotor conduction and functional improvement can confirm the potential of the time factor. Non-invasive neuromodulation has been shown to work for combat spinal cord injury of varying severity.

Material and methods: We have analysed 154 cases of severe combat spinal cord injury, followed continuously for at least 12 months from the start of neurorehabilitation. A unified «end-to-end» protocol combined rTvMS of the spinal cord with simultaneous TcES of peripheral nerves in different modes was developed for non-invasive spinal cord neuromodulation.

Results: The combination of these parameters produced the most positive results in post-traumatic sensory-motor disorders: (i). rTvMS, level ThX-LI: 2000 pulses per set, 100 pulse packages, 5-10 Hz, intensity "+ 30--40%" of the threshold of the evoked motor potential; TcES n. tibialis or n. peroneus: 5-10 Hz, pulse intensity corresponded to the threshold of the motor response, functional electrical stimulation (FES) mode. (ii). rTvMS, level C_II-Th_II: 2000 pulses per set, 50 pulse packages, 5-7 Hz, intensity + 20-30% of the threshold of the evoked motor potential; TcES n. medianus or n. ulnaris; n. tibialis or n. peroneus: 5-10 Hz, pulse intensity corresponded to the threshold of the motor response, FES mode. Approximately 28% of patients in group A (FRANKEL/ASIA) moved to a higher level of function after 3 courses of neurorehabilitation intervention (90 working days).

Conclusions and clinical implications: Electro-magnetic stimulation of the spinal cord excitatory cell conduction system according to the principle of "end-to-end: as in Hebb's theory," combined with physical movement, led to an increase in spinal cord conduction in the acute phase of combat spinal cord injury. This was manifested by neurological and functional improvement.

Keywords: combating spinal cord injury; early neurorehabilitation; non-invasive electrical stimulation of peripheral nerves; transvertebral magnetic stimulation for spinal cord injury.

Fig. 1

In this study, patients with sensorimotor deficit level B (incomplete) predominated at baseline. The total number of cases with incomplete CSCI was 72%.

Fig. 2

Low-intensity and high-volume neurorehabilitation activities dominated. An analysis shows that patients in these groups had psychological or neurological complaints that prevented them from attending 7–9 h of rehabilitation sessions in the first 3 months. Some complained of not being able to withstand the load, some of the intensity of the classes, some of frequent wound dressings, some of contact ulcers and long-term back pain and some of external fixation devices for gunshot fractures.

Fig. 3

The development of this protocol is based on Hebb’s postulate of associative learning at the cellular level between 2 neurons, leading to a constant modification of the activity pattern of a spatially distributed ensemble of nerve cells. The learning process means that new connections are formed, and existing connections are strengthened (the strength of the connection increases) between 2 mutually active neurons involved in constant or periodic activation of each other over time (12, 13). TVMS: transvertebral magnetic stimulation; ES: electrical stimulation. The idea behind this protocol is as follows. They are assuming that during a spinal cord injury, there are conditions where the preserved connections between neurons have a weak strength, or there are opportunities for 2 neurons to form new connections when activating each other, increasing their strength over time on a microscale, which has no clinical manifestation on a macroscale. A cellular network with multidirectional impulse movement can be hypothetically and simplistically considered a conductor with 2 ends, where excitatory elements are at the ends, and in the middle, there is a functional «weak» synapse or a damaged «synapse» or a «traumatic obstacle» that disrupts the impulse. Thus, there are substantial grounds for the fact that systematic, prolonged almost synchronous (with a certain delay) electromagnetic stimulation of a conductor from both ends (above and below the level of the obstacle or weak synapse) can create conditions for strengthening the “weak synapse” or adaptive bypass of the functional obstacle through a new connection between the 2 ends of the conductor, that is neurons, which will already have a positive effect on the macro scale. The “end-to-end” protocol was developed for such synchronous (simultaneous) stimulation, using transvertebral magnetic stimulation of the spinal cord and electrical stimulation with direct current of the peripheral nerves and indirectly of the spinal cord. In the figure, the image of the coil means that the magnetic effect is applied above the location of the “functional obstacle or ‘weak’ synapse” and the simultaneous effect with a specific short time delay of direct electric current on the nerve area below the level of the functional obstacle in the NMES mode and with motor muscle reinforcement in the FES mode.

Fig. 4

Depending on the topographic level of spinal cord damage according to the defined FRANKEL/ASIA zone of partially preserved function, select the appropriate projection locations for transvertebral spinal cord stimulation and simultaneous stimulation of the corresponding functional peripheral nerves on the same side of the stimulation and set the appropriate time delay in seconds to determine the sequence of stimuli (1 stimulus should be preceding). The functional obstacle should be hypothetically located between the home ends of an imaginary conductor to which stimuli are applied. Choose different combinations: TMVS+ES (NMES or FES).