Diaphragm Pacing Stimulation System for Tetraplegia in Individuals Injured During Childhood or Adolescence

Abstract

Background: Children with cervical spinal cord injury and chronic respiratory insufficiency face the risks and stigma associated with mechanical ventilators. The Diaphragm Pacing Stimulation (DPS) System for electrical activation of the diaphragm is a minimally invasive alternative to mechanical ventilation.Methods: Review of patients in a prospective Food and Drug Administration trial of the DPS System in individuals who were injured at age 18 years or younger. The procedure involved laparoscopic mapping to locate the diaphragm motor points with electrode implantation. Two weeks after surgery, stimulus/output characteristics of each electrode were determined to obtain an adequate tidal volume for ventilation. A home-based weaning protocol from the ventilator was used.Results: Of 28 patients implanted with the DPS System, 10 had sustained cervical SCI as children or adolescents. Average age at injury was 13 years (range 1.5 to 17 y). Age at implantation ranged from 18 to 34 years. Length of time from injury to implantation averaged 9.7 years (0.8 to 19 y). All patients tolerated the implantation procedure. Four patients utilize DPS continuously (24/7), 4 patients pace daytime only, and 2 patients are still actively conditioning their diaphragms. Two patients required surgical correction of scoliosis prior to implantation. All patients prefer breathing with the DPS and would recommend it to others; 4 patients specifically identified that attending college or church without a ventilator eases their integration into society. Conclusions:The results show that the laparoscopic DPS system can be safely implanted in tetraplegics injured as children and used in a home-based environment to wean them off of mechanical ventilation.

Pediatric Spinal Cord Injury

“…Five of the individuals were candidates for DPS, the smallest weighing 15 kg. All patients achieved tidal volumes above basal needs and sufficient for ventilation [51]. Four of the children under age 10 developed anxiety with the conditioning onset, which may contribute to a longer period of conditioning.…”

“…Two individuals required surgical correction of scoliosis prior to implantation. All reported preference for DPS-triggered breathing over tracheal mechanical PPV, and four individuals identified DPS as facilitating integration into community activities [51].…”

Phrenic Nerve Pacing: Current Concepts

“…The voltage required to effect minimal (threshold) and maximal diaphragm motion during pacing was confirmed or adjusted about once a month (41). Alternatively uninterrupted simultaneous pacing of both hemidiaphragms, using a low-frequency stimulation (7)(8) with a respiratory rate of 5 to 9 per minute may be appropriate for adult patients (41). In general the transition from mechanical ventilation to chronic full-time pacing must be individualized for each patient (4).…”

“…More than 80% of injuries are traumatic in nature, and up to 1.5% of such injuries are sustained in children. Many of these patients cannot be eventually weaned off mechanical ventilation, and require chronic ventilator support in as much as 4% of the cases (4,6,7,8). In the United States more than 100,000 tracheostomies are performed for patients who are unable to be weaned from ventilator (8,9).…”

“…Mechanical ventilation in tracheostomy patients has several complications such as speech difficulties, reduced mobility, difficulty with transfers, social limitations, loss of sense of smell, equipment malfunction, increased respiratory infections, and increased cost of care approaching $200,000 a year (7,8,10,11).…”