Course, predictors of diaphragm recovery after phrenic nerve injury during pediatric cardiac surgery

Background Hemidiaphragm paralysis from phrenic nerve injury is a known complication of congenital cardiac surgery. Return of diaphragm function has been reported; however, prior studies on this subject have been limited by small numbers, static assessment methods, or observation of plicated or non-plicated patients alone. To describe return of function, we reviewed fluoroscopy and ultrasonography in all diagnosed cases of diaphragmatic paralysis. Methods Surgical cases at our institution between 1991 and 2010 were identified for patients with postoperative hemidiaphragm paralysis diagnosed by chest X-ray, ultrasound, or fluoroscopy. Follow-up ultrasound and fluoroscopic studies were reviewed for return of diaphragm function. Results Seventy-two cases of postoperative hemidiaphragm paralysis were identified. Forty cases were plicated prior to discharge. Plicated patients were younger at time of diagnosis (median 46 days average 3.6 months; p = 0.025) and had a larger proportion of single ventricle diagnoses (48% vs 16%) compared with non-plicated patients. Twenty-six patients with paralysis were excluded in follow-up due to lack of studies documenting diaphragm function after the diagnostic study. Of the remaining 46 cases, median follow-up was 353 days (range: 6 days to 17 years). Plicated and non-plicated patients regained function at similar frequency (60% and 54.8%, respectively). Plication status, Risk Adjustment for Congenital Heart Surgery (RACHS) 1 score, age at diagnosis, and side of paralysis did not predict failure of recovery. Conclusions In the current era, return of diaphragm function after phrenic nerve injury sustained during congenital cardiac surgery is a known occurrence; however, predicting recovery continues to be difficult.