Deep Brain Stimulation in Patients With Incomplete Spinal Cord Injury for Improvement of Gait

Spinal cord injuries are anatomically mostly incomplete, showing tissue bridges of the spinal cord at the injury site. Of the 60% functionally incomplete patients, about half face a life in the wheelchair. Besides conventional rehabilitation, no prominsing further treatment options exist. One of the most plastic systems involved in locomotion is the pontomedullary reticulospinal tract, which is the oldest locomotor command system existing in most vertebrates, including primates. Muscle activation patterns for limb movements are programmed in the spinal cord and have to be activated and coordinated through commands from the so called mesencephalic locomotor region (MLR). The MLR consists of nerve cells in the lower mesencephalic tegmentum sending uni- and bilateral signals through the medullary reticulospinal tracts. Classical physiological studies showed that electrical stimulation of the MLR induce locomotion. For the first time this approach was transferred and recently published in a model of induced incomplete spinal cord injury by the Schwab group. Rats severly impaired in motor hindlimb control with only 10-20% spared white matter, recovered with fully functional weight bearing locomotion under MLR deep brain stimulation (DBS). Even rats with only 2-10% spared white matter regained weight supporting stepping. DBS is a clinical standard treatment option in patients with movement disorders but does not relieve all symptoms. Therefore, small studies of MLR stimulations have been safely used in Parkinsonian patients showing freezing of gait and frequent falls with variable results. In a translational approach, we aim at performing a multidisciplinary phase one clinical trial with 5 patients and incomplete spinal cord injury. With the means of our established universitary setup for DBS treatments the operations will be performed unilaterally under local anaesthesia in the Division of Neurosurgery, USZ, with perioperative electrophysiological recordings, clinical as