Incidence of vocal fold paralysis in infants undergoing ligation of patent ductus arteriosus

Background. Left-sided, iatrogenic vocal fold paralysis (IVFP) secondary to recurrent laryngeal nerve injury is a potential complication of ligation of patent ductus arteriosus (PDA). This study investigates specific risk factors associated with IVFP. Methods. A retrospective chart review was performed for all infants 12 months of age or younger who underwent operative PDA closure at the University of Iowa from January 1, 1991, to January 1, 1994. Results. Six cases of IVFP were diagnosed in 68 infants who underwent PDA ligation using clips (52.9%), suture ligatures (41.2%), or both (5.9%). Compared with infants without postoperative IVFP, infants with IVFP were smaller at birth (0.9 versus 2.3 kg; p < 0.001) and more premature (gestational age, 26.3 versus 33.8 weeks; p < 0.001), and were smaller 11.1 versus 3.4 kg; p < 0.001) and younger (31.9 versus 88.4 days; p < 0.001) at operation. Weight gain from birth to operation was significant only in infants without postoperative IVFP (p < 0.05). Although the overall incidence of IVFP in all infants undergoing PDA closure was 8.8%, five of the six cases (83.3%) of IVFP occurred in extremely low birth weight infants, ie, those weighing 1 kg or less at birth. Among the cohort of extremely low birth weight babies undergoing operation, the incidence of IVFP was 22.7%. Iatrogenic vocal fold paralysis was associated only with the use of surgical clips; however, because clips were used in 90.9% of the premature infants requiring PDA ligation, it was not possible to establish whether suture ligature is a safer technique. Conclusions. This study demonstrates that the single major risk factor for IVFP after ligation of PDA is birth weight less than 1 kg.