Use of Diaphragm Pacing in the Management of Acute Cervical Spinal Cord Injury

Educational Objectives

The goal of this program is to improve management of acute cervical spinal cord injury. After hearing and assimilating this program, the clinician will be better able to:

1. Recognize respiratory dysfunction following acute cervical spinal cord injury.
2. Identify patients with acute cervical spinal cord injury who would benefit from diaphragmatic pacing.

Summary

Respiratory dysfunction in acute cervical spinal cord injury (SCI): phrenic nerve innervation (C3-C5) controls diaphragmatic function; cervical SCI results in reduced vital capacity from paralysis of inspiratory muscles, decreased chest wall and lung compliance, impaired cough effort, and increased secretions with elevated bronchial tone; secretion accumulation creates life-threatening complications, eg, complete bronchial obstruction requiring emergent bronchoscopy; chest radiograph showing acute lobar collapse demands immediate intervention to prevent desaturation, bradycardia, and asystole

Impact of mechanical ventilation on diaphragm function: positive pressure ventilation induces rapid diaphragmatic atrophy, with muscle fiber changes visible on biopsy in <24 hr; transdiaphragmatic pressure monitoring demonstrates progressive decline in contractile force; distortion of respiratory mechanics creates inefficient ventilation, which is particularly pronounced during bronchial obstruction and pneumonia; patients cannot generate sufficient respiratory effort to sustain ventilation without mechanical support

Clinical burden of ventilator-dependent cervical SCI: nearly all of complete injuries above C5 and majority of C5 to C7 complete injuries require tracheostomy; incomplete injuries have lower tracheostomy rates; ≈20% of patients with acute cervical SCI and tetraplegia are ventilator-dependent upon transfer to rehabilitation; complete C1-C4 injuries universally require tracheostomy

Economic and survival impact: first-year costs for high cervical injuries (C1-C4) are >$1 million based on 2017 data, and are likely substantially higher in 2025; lifetime costs approach $5 million for young patients; ventilator dependence profoundly impacts longevity, with mean survival of 19 yr for patients weaned from mechanical ventilation vs approximately one-half that duration for patients dependent on a ventilator in a study of individuals 31 to 45 yr of age at time of injury

Rationale for diaphragmatic pacing system (DPS): systematic review (2016-2018) established safety and efficacy for ventilator liberation in patients with chronic ventilator dependence; early implantation was suggested as potentially superior to delayed implantation; chronic implantation data from 92 patients showed ventilator liberation rate of 61%, with average time to implant of 48 mo; three-quarters of successful liberations occurred ≤1 yr post-implant, supporting earlier intervention strategy

Acute implantation: hypothesis—early DPS implantation may prevent recurrent ventilator-associated pneumonia, facilitate ventilator liberation, reduce intensive care unit (ICU) length of stay and mortality from septic complications, and expedite transfer to rehabilitation; alternative to prolonged ICU stays (6-8 wk) with associated complications including contractures and pressure ulcers; feasibility data—multicenter experience (8 centers, 29 patients, 22 implants) demonstrated that ≈25% of patients had non-stimulatable diaphragms and were not candidates; 75% had stimulatable diaphragms; 80% of patients who received implantation achieved ventilator liberation; average time to implant was 40 days post-injury; average time to wean post-implantation was 10 days (compared with 4 yr in chronic setting)

Single-center outcomes study: analysis of 649 patients with acute cervical SCI (January 2005-2017) included 40 DPS implants matched with 61 controls using propensity scoring; both groups had high injury severity scores, presence of shock, tachycardia, and severe chest injury; spinal cord characteristics showed that approximately one-third of patients had C1 to C4 injuries, and approximately two-thirds had C5 to C7 injuries, with >80% complete injuries in each group; mortality occurred in one patient in the DPS group vs 9 in the control group; ICU length of stay decreased but remained substantial (≈1 mo); no significant difference in ventilator-associated pneumonia rates were observed; improvement in respiratory mechanics—subsequent analysis examined spontaneous tidal volumes pre- and post-implantation; patients who received DPS showed 88-mL increase in spontaneous tidal volume post-implantation; control group (non-pacing) demonstrated 15-mL decrease in spontaneous tidal volume at day 14; days to ventilator liberation—was 10 days with DPS vs 29 days without DPS; findings supported mechanism of improved respiratory mechanics facilitating liberation; economic outcomes—multivariate logistic regression analysis with hospital charges normalized to 2019 data showed significant cost reduction; hospital charges in the control group were >$750,000; hospital charges in the DPS group (39 survivors) was ≈$600,000, ie, DPS implantation was associated with ≈$150,000 reduction in hospital charges; decreased ventilator length of stay (10 vs 29 days) drove cost reduction

Current guidelines: American Association for the Surgery of Trauma Quality Improvement Program (AAST-QUIP) best practices guidelines for ventilator management in acute cervical SCI recommend early tracheostomy and consideration of diaphragmatic pacing system; recommendations are based on improved tidal volume, facilitation of ventilator liberation, and potential cost reduction

Surgical technique for laparoscopic implantation: diagnostic laparoscopy approach is accessible to any surgeon facile with laparoscopic techniques; port placement is similar to that for laparoscopic Nissen fundoplication, with one sans trocar at umbilicus, one subxiphoid 12-mm trocar, and 2 subcostal 5-mm trocars; 4 electrodes are implanted (2 per hemidiaphragm: anterior and posterior positions); electrode wire diameter comparable to that of a retractable badge holder cord; specialized instrument with internal needle is used for electrode deployment via 12-mm trocar; technique involves beveling needle into diaphragm, tenting tissue, grasping electrode wire, and retracting the instrument; electrodes tunneled through subxiphoid port and brought out below the costal margin; stimulation produces vigorous hemidiaphragmatic contraction; external pulse generator (smartphone-sized, slightly thicker) connects to electrodes

Function and management of DPS: system conditions diaphragm to facilitate ventilator liberation; used only during spontaneous respiration (requires airway pressure release ventilation or pressure support modes); does not synchronize with ventilator; deactivated if patient requires return to full ventilator support; restores functional breathing and improves secretion clearance; identically programmed backup pulse generator is provided with the system for equipment failure scenarios; patient can spontaneously initiate breaths even with system off, allowing time for troubleshooting or device replacement

Patient selection criteria: initial approach was selective with phrenic nerve electromyography or fluoroscopic sniff testing to confirm nerve function; evolved to evaluating all patients with acute cervical SCI and respiratory failure, particularly complete injuries; current strategy focuses on resuscitation and stabilization, followed by cervical spine stabilization procedure; tracheostomy, percutaneous endoscopic gastrostomy, and pacing implantation are planned as coordinated procedures; timing is optimized to first week post-injury (reduced from initial 14-day average) to maximize benefit

Program implementation strategies: requires identified champion to drive adoption; collaboration with multidisciplinary teams is essential; value analysis required given expensive technology; economic case is based on demonstrated decreased length of stay and ventilator days offsetting device costs; extensive education is necessary for nursing, rehabilitation services, physical therapy, speech therapy, and occupational therapy staff; staff education addresses concerns about device disconnection or failure (eg, patients retain spontaneous breathing capability, bag-valve-mask ventilation is available, backup device is immediately accessible); case management coordination is required to identify appropriate placement facilities and educate rehabilitation centers on technology; billing infrastructure including International Classification of Diseases, 10th Revision codes, Current Procedural Terminology codes, and diagnosis-related group assignments is necessary; implementation requires patience, persistence, and sustained institutional commitment

Readings

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Kerwin was recorded at the 73rd Annual Detroit Trauma Symposium, held on November 6-7, 2025, in Detroit, MI, and presented by The Michael and Marian Ilitch Department of Surgery, Wayne State University School of Medicine, Detroit, MI. For information about upcoming CME activities from this presenter, please visit detroittrauma.org. Audio Digest thanks Dr. Kerwin and The Michael and Marian Ilitch Department of Surgery, Wayne State University School of Medicine, Detroit, MI for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

Lecture ID:

GS730801

Qualifies for:

ABS Continuous Certification, Trauma

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.