Design: This paper describes a treatment paradigm to facilitate functional gait in a quadriplegic, ASIA C spinal cord injured (SCI), wheelchair-dependent subject who presented with some large ®ber sensation, sub-functional motor strength in all lower limb muscles, and moderate spasticity. The study utilizes partial weight bearing therapy (PWBT) followed by epidural spinal cord stimulation (ESCS) with the assumption that both treatments would be necessary to elicit a well organized, near eortless functional gait with a walker. Function is de®ned in terms of accomplishing task-speci®c activities in the home and community. Objectives: To demonstrate the feasibility and bene®ts of combined PWBT and ESCS therapies aimed at promoting functional gait in a wheelchair-dependent ASIA C SCI subject. Setting: The Clinical Neurobiology and Bioengineering Research Laboratories at Good Samaritan Regional Medical Center, Phoenix, Arizona, USA, and the Department of Bioengineering, Arizona State University, Tempe, Arizona, USA. Methods: The study began with the application of PWBT. The subject walked on the treadmill until a plateau in gait rhythm generation was reached. Subsequently, ESCS, applied to the lumbar enlargement, was utilized to facilitate PWBT and, later, over-ground walking for a standard distance of 15 m. Gait performance was analyzed by measuring average speed, stepping symmetry, sense of eort, physical work capacity, and whole body metabolic activity. Results: PWBT led to improved stereotypic stepping patterns associated with markedly reduced spasticity, but was insucient for over-ground walking in terms of safety, energy cost, and fatigue. ESCS with PWBT generated immediate improvement in the subject's gait rhythm when appropriate stimulation parameters were used. When compared to the non-stimulated condition, over-ground walking with ESCS across a 15 m distance was featured by a reduction in time and energy cost of walking, sense of eort, and a feeling of`lightness' in the legs. After a few months of training, performance in speed, endurance, and metabolic responses gradually converged with/without ESCS at this short distance, suggesting a learned response to these conditions. However, at longer distances (eg, 50 ± 250 m), performance with ESCS was considerably superior. The subject was able to perform multiple functional tasks within the home and community with ESCS. Conclusion: We propose that ESCS augments the use-dependent plasticity created by PWBT and may be a valuable adjunct to post-SCI treadmill training in ASIA C subjects. We also conclude that ESCS elicits greater activation of an oxidative motor unit pool, thereby reducing the subject's sense of eort and energetic cost of walking.

We investigated a novel treatment paradigm for developing functional ambulation in wheelchair-dependent individuals with chronic, incomplete spinal-cord injury. By coordinating epidural stimulation of the dorsal structures of the spinal cord with partial weight bearing treadmill therapy, we observed improvement in treadmill and over-ground ambulation in an individual with chronic incomplete tetraplegia. The application of partial weight-bearing therapy alone was not sufficient to achieve functional ambulation over ground, though treadmill ambulation improved significantly. Combining epidural spinal-cord stimulation (ESCS, T10-T12 vertebral levels) with partial weight-bearing therapy resulted in further improvement during treadmill ambulation. Moreover, the combination of therapies facilitated the transfer of the learned gait into over ground ambulation. Performance improvements were elicited by applying continuous, charge-balanced, monophasic pulse trains at a frequency of 40-60 Hz, a pulse duration of 800 micros, and an amplitude determined by the midpoint (50%) between the sensory and motor threshold values. The participant initially reported a reduction in sense of effort for over ground walking from 8/10 to 3/10 (Borg scale), and was able to double his walking speed. After several weeks of over ground training, he reached maximum walking speeds of 0.35 m/s, and was able to ambulate over 325 m. We propose that ESCS facilitated locomotor recovery in this patient by augmenting the use-dependent plasticity created by partial weight bearing therapy. Confirmation of these promising results in a controlled study of groups of spinal-cord-injured subjects is warranted.

Pharmacologic management of spasticity of spinal origin is determined in part by several factors: 1) evidence of a spasticity-related dysfunctional profile, 2) acknowledgement of the clinical effectiveness and side effects of commonly utilized pharmacologic agents, 3) pathophysiologic mechanisms and spinal plasticity (neuronal excitability, anatomical and biochemical reorganization), 4) pharmacokinetics and subject compliance, and 5) unique methods of drug administration. Presently, preferred agents include systemically administered substances, which presumably act at the level of segmental and intersegmental interneuronal circuitry-e.g. baclofen or clonidine, and at the level of muscle contractile tissue-e.g. dantrolene sodium. This paper also describes the action of intrathecally administered morphine on spinal spasticity in subjects resistant to the action of oral agents.