Diaphragm stimulation after human spinal cord injury: Effects on respiratory function and diaphragm muscle activation.

Abstract

Respiratory dysfunction is a leading cause of morbidity and mortality after cervical spinal cord injury (C-SCI). Respiratory impairment is exacerbated by mechanical ventilation, which is associated with higher infection rates and diaphragm atrophy. Intramuscular stimulation of the diaphragm, that is, diaphragm pacing (DP), is a potential strategy to facilitate ventilator weaning, enhance respiratory function, and reduce complications. However, its impact on respiratory recovery and neuromuscular activation remains understudied. This prospective observational case series evaluated changes in respiratory function and diaphragm activation over two months in 11 patients with acute traumatic C-SCI who underwent DP. Outcomes included tidal volume, respiratory rate, minute ventilation, maximal inspiratory/expiratory pressure generation (MIP/MEP), forced vital capacity (FVC), and diaphragm electromyography (EMG) recorded from the implanted electrodes. Participants demonstrated severe respiratory impairment at baseline, with tidal volumes averaging 2.8±1.3 mL/kg and FVC at 19±14% of predicted. Despite this, 89% weaned from mechanical ventilation within 41±19.8 days post-injury. Significant weekly improvements were evident in tidal volume (+0.26 mL/kg), respiratory rate (-0.66 breaths/min), and minute ventilation (+0.35 L/min). MIP and MEP increased by 3% predicted function per week, and FVC increased by 2% of predicted function per week. Diaphragm EMG amplitudes during quiet breathing decreased over time, particularly in patients with high baseline activation (>80% of maximum) possibly reflecting improved neuromuscular efficiency. These findings suggest that DP may support early respiratory recovery after C-SCI improving respiratory function and diaphragm activation. Future research is needed to elucidate the underlying mechanisms and optimize clinical use of DP for respiratory recovery after C-SCI. (J Trauma Acute Care Surg 2026;00:000-000. Copyright © 2026 Wolters Kluwer Health, Inc. All rights reserved.). Therapeutic Study; Level IV.