0935 Vocal cord paralysis after ductal ligation in ELBW infants
Patent ductus arteriosus (PDA) occurs in up to 80% of extremely low birthweight (ELBW) neonates with a significant number going on to surgical ligation after failed medical therapy. Ligation has been regarded as a relatively minor and innocuous procedure, often performed in the neonatal intensive care unit. Recently, however, it has been shown that left vocal cord paralysis (LVCP) may be a consequence of surgery and trauma to the left recurrent laryngeal nerve in up to two-thirds of ELBW infants undergoing PDA ligation; a much higher incidence than the 1.7 – 11.5% rate cited for all age/weight groups, and apparently more likely to persist in the ELBW. The reports of LVCP have come from single-centre studies; another from Duke University has recently not only confirmed the high rate of LVCP in an ELBW group, but has also shown significant morbidity in symptomatic infants on follow up. Sixty ELBW infants born between 2004 and 2006 underwent ligation for failed medical treatment (or where medical treatment was contraindicated) and 55 who survived to discharge were eligible for direct laryngoscopy for failure to wean off the ventilator, stridor, hoarse or absent cry, or cardiorespiratory distress with feeds. Means for birthweight, gestational age and age at ligation were 725g, 25 wks and 20 days respectively. Symptoms warranting laryngoscopy occurred in 25 of the 55, and 22 were found to have LVCP (i.e. overall incidence of 40%, with 80% of symptomatic infants having confirmed paralysis). There was a non-significant trend towards lower weight, earlier ligation and more severe IVH in the LVCP group. When compared to non-LVCP infants these required longer assisted ventilation (44 vs 29 days), were more likely to require gastrostomy for abnormal swallow or aspiration (63% vs 6%), develop BPD (82% vs 39%), undergo Nissen fundoplication (41% vs 3%) or subsequently develop reactive airway disease (86% vs 33%). Underlying problems related to the LVCP and the consequent morbidity include inability to maintain a functional residual capacity due to glottic incompetence, repeated micro-aspiration, possible airway remodelling, and abnormal swallow. These findings should alert one to the possibility of LVCP in ELBW infants whose clinical course has required surgical intervention for PDA, and perhaps also encourage one to persevere with medical management in this group before resorting to ligation.

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