Restoration of respiration in high cervical spinal cord injury via phrenic nerve reinnervation: illustrative case

Abstract

Background: Traumatic high cervical spinal cord injury (SCI) can result in a devastating loss of functional respiration, leaving patients permanently dependent on mechanical ventilation. Nerve transfer is a promising reinnervation strategy that has the potential to restore connectivity in paralyzed distal muscles. The spinal accessory nerve (SAN) remains functional in most cases after high cervical SCI and can serve as a donor to reinnervate the phrenic nerve (PN), thereby improving diaphragmatic function.

Observations: Information regarding thorough physical, electrodiagnostic, and pulmonary assessments to establish candidacy for nerve transfer, as well as the surgical procedure, was summarized with an illustrative case. The patient demonstrated improvement in pulmonary function testing but did not achieve independent respiration. A systematic literature review identified 3 studies with 9 additional patients who had undergone SAN-to-PN transfer. The nerve transfer meaningfully restored diaphragmatic function, improving pulmonary function tests and reducing ventilator dependency.

Lessons: Respiratory dependency significantly impacts the quality of life of patients with a high cervical SCI. The use of the lower SAN motor branch for PN transfer is safe and does not result in a meaningful downgrade in trapezius function. Outcomes following this procedure are promising but heterogeneous, indicating a need for significant innovation and improvement for future therapies. https://thejns.org/doi/10.3171/CASE24236.

Keywords: diaphragm reinnervation; nerve transfer; phrenic nerve; respiration; spinal accessory nerve; spinal cord injury.

FIG. 1.

A: Lateral view showing the distal SAN motor branch transferred to the PN. B: Anterior view of the right SAN-to-PN transfer. The contralateral gray nerve and muscle indicate a lack of innervation and atrophy. Created with BioRender.com.

FIG. 2.

A: Photograph of a planned supraclavicular incision to expose the anterior triangle of the neck and identify the SAN and PN. B: Following exposure, the SAN and PN are identified and isolated in vessel loops. C: Both the SAN and PN underwent extensive neurolysis until an adequate length was available for tension-free nerve transfer. D: Microscopic view of both the donor SAN and recipient PN, sharply transected and placed on a blue background for planned neurotization. E: Neurotization and nerve transfer were performed by coapting donor and recipient segments with 9-0 epineurial sutures (black arrow). F: Nerve transfer reinforced by fibrin glue (black arrow). Cr = cranial; Rt = right side.