Inspiratory Muscle Pacing in Spinal Cord Injury: Case Report and Clinical Commentary

Abstract

Background/Objective: A significant fraction of patients with cervical spinal cord injury suffer from respiratory muscle paralysis and dependence on chronic mechanical ventilation. In selected patients, diaphragm pacing (DP) through electrical stimulation of the phrenic nerves provides an alternative to mechanical ventilation with significant advantages in life quality.Methods: A case report of an individual who successfully underwent DP using intramuscular diaphragm electrodes. A brief review of the state of the art of DP including the clinical benefits of DP, patient selection and evaluation, description of equipment, methods of transition from mechanical ventilation to DP, potential complications and side effects, long-term outcome, and potential future developments in this field is included.Results: Several available DP systems are available, including conventional ones in which electrodes are positioned directly on the phrenic nerves through thoracotomy and less invasive systems in which electrodes are placed within the diaphragm through laparoscopy. For patients with only unilateral phrenic nerve function, a combined intercostal and unilateral diaphragm pacing system is under development. Conclusions:In patients with ventilator-dependent tetraplegia, there are alternative methods of ventilatory support, which offer substantial benefits compared to mechanical ventilation. Med. 2006;29:95-108 J Spinal Cord

Functional electrical stimulation after spinal cord injury: current use, therapeutic effects and future directions

“…71 Early implantation, even within weeks of acute SCI, of all system components is ultimately envisioned. 71 DiMarco et al 73 have recently described in detail shortcomings of currently used EPR systems and outlined needs for their further development. In most cases, viability of only one phrenic nerve is not sufficient to allow breathing exclusively by EPR only.…”

“…In recent years, it has been shown that accurate mapping of the phrenic nerve motor points permits successful laparoscopic implantation of intramuscular electrodes within the costal portion of each hemi-diaphragm. 51,73,71,72 Such procedure involves placement of four laparoscopic ports to the abdominal cavity for creation of a pneumoperitoeum, visualization of the diaphragm, diaphragmatic mapping by electrical stimulation and implantation of two electrodes at the motor points in each hemi-diaphragm. 73 The electrode wires are tunneled subcutaneously to the chest wall where they exit and connect to an external stimulator.…”

“…To allow for adequate healing, stimulation is usually not started until 2 weeks postoperatively by using supramaximum stimulus amplitude and the lowest frequency capable of generating diaphragmatic response. 73 Stimulation is initially done daily for 10-15 min every hour and gradually increased, but it may take 2-3 months before muscle reconditioning is considered complete. An early goal is to allow ventilator-free breathing by EPR during the waking hours only, followed by EPR during sleep as well.…”

Respiratory muscle pacing with chronically implanted intramuscular Permaloc electrodes: A feasibility study

“…Accessory muscles can also assist the diaphragm by lifting the upper thorax. Abdominal muscles are the primary muscles for cough and include the rectus and transversus abdominis and the internal and external obliques [1][2]. Patients with upper-cervical spinal cord injury (SCI) have paralysis of these respiratory muscles (although accessory respiratory muscles may still be active).…”

“…Between 200 and 400 new SCI patients each year in the United States have this paralysis and the associated respiratory failure. Atelectasis and infection are the number one cause of death for these individuals [1][2].…”