Combined intercostal and diaphragm pacing to provide artificial ventilation in patients with tetraplegia

Objective: To evaluate the usefulness of combined intercostal and diaphragm pacing to maintain independence from mechanical ventilation. Design: A prospective trial. Participants: Four ventilator-dependent subjects with spinal cord injury with only unilateral phrenic nerve function. Intervention: During an initial surgical procedure, a multipolar epidural disk electrode was positioned on the ventral surface of the upper-thoracic spinal cord via a hemilaminectomy to activate the inspiratory intercostal muscles. A phrenic nerve electrode was implanted unilaterally via the thoracic approach. Main Outcome Measures: Inspired volume production and duration that subjects could be comfortably maintained when off mechanical ventilatory support. Results: Initial maximum inspired volumes from combined intercostal and diaphragm stimulation ranged between .23 and .93L and significantly increased over the course of reconditioning period to between 0.55 and 1.31L; subjects could be maintained off mechanical ventilation between 16 and 24 hours a day. Conclusions: Combined intercostal and unilateral diaphragm pacing may be a useful therapeutic modality capable of maintaining long-term ventilatory support in patients with only unilateral phrenic nerve function.