Diaphragm Interventions in Acute Flaccid Myelitis: A Single-Center Retrospective Case Series of Diaphragm Pacing Systems and Phrenic Nerve Transfers.

BACKGROUND

Acute flaccid myelitis (AFM) affects anterior horn cells of the spinal cord, leading to paralysis of proximal extremity and respiratory musculature. Patients can have chronic respiratory insufficiency and remain dependent on mechanical ventilation. We aim to report outcomes of diaphragm pacing systems (DPSs) and/or phrenic nerve transfers to augment diaphragm function in patients with AFM.

METHODS

This is a single-center, retrospective series of patients with AFM and chronic respiratory insufficiency who underwent operative intervention to augment diaphragm function. Patients underwent placement of DPS, phrenic nerve transfer, or both. We collected information on demographics, clinical characteristics, electrodiagnostic results, and operative findings. We assessed outcomes of diaphragm ultrasound excursion and respiratory mechanics.

RESULTS

Six patients underwent operative intervention between 2014 and 2023. Four (66%) were male. Median age of onset was 4.3 years (range 2.8-5.7). Median follow-up was 29.3 months (range 8.1-48). There were 5 DPS placements and 3 phrenic nerve transfer operations performed, including two patients who received both procedures. Patients who underwent DPS as the primary intervention did not show improvement attributable to pacing, as similar outcomes were observed in matched controls who did not receive interventions. One patient with complete denervation had diaphragm reanimation following phrenic nerve transfer, achieving voluntary and spontaneous respiration.

CONCLUSIONS

Patients with AFM and chronic respiratory insufficiency may benefit from operative intervention to improve respiratory function. DPS alone did not show consistent improvement in respiratory outcomes. Phrenic nerve transfer is feasible to reanimate the paralyzed diaphragm and restore spontaneous respiration or facilitate pacing.