Recurrent laryngeal nerve injury and aspiration following patent ductus arteriosus ligation: A systematic review Emma Holmes BSc1, Carrie Liu MD2, James Brookes MD3, Warren Yunker MD PhD4 1Cumming School of Medicine, University of Calgary, Calgary, Alberta 2Department of Surgery, Divisions of Otolaryngology, Cumming School of Medicine, University of Calgary, Calgary, Alberta 3 Department of Surgery, Divisions of Otolaryngology and Pediatric Surgery, Cumming School of Medicine, Alberta Children’s Hospital, University of Calgary, Calgary, Alberta 4 Department of Surgery, Divisions of Otolaryngology and Pediatric Surgery, Cumming School of Medicine, Alberta Children’s Hospital, University of Calgary, Calgary, Alberta BACKGROUND METHODS DISCUSSION Incidence of patent ductus arteriosus (PDA) in Canadian neonates has been increasing from 38% to 43% in preterm infants from 1997-2007, and is a common cardiovascular problem in newborns[1] Surgical intervention is needed when medical treatment of PDAs fail[2] Risks of surgery include injury to the recurrent laryngeal nerve, and can result in vocal cord immobility (VCI)[3] Vocal cord immobility is associated with morbidities such as dysphagia, dysphonia, and respiratory symptoms[3] The most common cause of VCI is iatrogenic injury from associated cardiac surgery (43%)[4] A comprehensive search using PRISMA guidelines of Medline, Embase, and The Cochrane Library was conducted, and limited to English publications 54 articles identified and reviewed. Three investigated aspiration in patients with VCI post-PDA ligation surgery and met inclusion criteria Inclusion criteria was limited to studies which: Assessed PDA ligation surgery outcomes Pediatric patient population <18 years Performed and reported swallowing assessments Where data was available, odds ratios (95% confidence interval) was calculated, and plotted Of the 54 studies screened and eligible, 3 fit inclusion criteria for analysis The recorded incidence of VCI and aspiration in these studies is likely lower than the true incidence, because the majority of studies only assessed patients that were symptomatic Children with VCI, as a complication of PDA ligation, have higher odds of aspirating compared to counterparts without VCI It is important to identify neonates that are aspirating so that their feeding management can be altered Limitations Lack of available studies in the literature investigating aspiration in neonates with VCI post-PDA ligation, resulting in small sample size for review Level of evidence for included studies is low RESULTS OBJECTIVES Figure 1: Flow diagram of study selection To review the literature and identify instances of aspiration in pediatric patients who had undergone PDA ligation and had vocal cord immobility Calculate how strongly the presence of vocal cord immobility is associated with aspiration in these patients CONCLUSIONS Overall incidence of aspiration among children with and without VCI was 73.7% and 4.8% respectively (odds ratio 26.0, p=0.006)(Table 1) Weighted and pooled odds ratio for aspiration was 26.02 (95% CI, 2.51 to 270.05)(Table 1) Heterogeneity analysis for random effects were Tau2 =2.09 (Table 1) Children with VCI have significantly higher odds of aspirating (OR 26.02) compared to counterparts Gaps in the literature limited analysis 46 full text articles were assessed for eligibility (Figure 1) Three studies met inclusion criteria and were combined in a limited meta-analysis using Review Manager (version 5.3.5) (Figure 1) Studies included for review: n= 80 patients 38 patients had unilateral VCI, 42 acted as controls Levels of evidence varied from 3-4 Weighted, and pooled odds ratio for aspiration was 26.02 [2.51, 270.05] (Table 1) REFERENCES [1] Shah PS, Sankaran K, Aziz K, Allen AC, Seshia M, Ohlsson A, Lee SK. Outcomes of preterm infants <29 weeks gestation over 10-year period in Canada: a cause for concern?. Journal of Perinatology. 2012; 32: 132-138. [2] Resende MHF, More K, Nicholls D, Ting J, Jain A, McNamara PJ. The impact of a dedicated patent ductus arteriosus ligation team on neonatal health-care outcomes. Journal of Perinatology. 2016; 36: 463-468. [3] Nichols BG, Jabbour J, Hehir DA, Ghanayem NS, Beste D, Martin T, Woods R, Robey T. Recovery of vocal fold immobility following isolated patent ductus arteriosus ligation. International Journal of Pediatric Otorhinolaryngology. 2014; 78: 1316-1319. [4] Carpes LF, Kozak FK, Leblanc JG, Campbell AI, Human DG, Fandino M, Ludemann JP, Moxham P, Fiori H. Assessment of vocal fold mobility before and after cardiothoracic surgery in children. Archives of Otolaryngology Head & Neck Surgery. 2011; 137(6): 571-575. [5] Clement AW, El-Hakim H, Phillipos EZ, Cote JJ. Unilateral vocal cord paralysis following patent ductus arteriosus ligation in extremely low-birth-weight infants. Archives of Otolaryngology Head & Neck Surgery. 2008; 134(1): 28-33. [6] Benjamin JR, Smith PB, Cotton CM, Jaggers J, Goldstein RF, Malcolm WF. Long-term morbidities associated with vocal cord paralysis after surgical closure of a patent ductus arteriosus in extremely low birth weight infants. Journal of Perinatology. 2010; 30: 408-413. [7] Malcolm WF, Hornik C, Evans A, Smith PB, Cotton CM. Vocal fold paralysis following surgical ductal closure in extremely low birth weight infants: a case series of feeding and respiratory complications. Journal of Perinatology. 2008; 28: 782-785. [8] Truong MT, Messner AH, Kerschner JE, Scholes M, Wong-Dominguez J, Milczuk HA, Yoon PJ. Pediatric vocal fold paralysis after cardiac surgery: rate of recovery and sequelae. Otolaryngology – Head and Neck Surgery. 2007; 137: 780-784. Table 1: Aspiration events in post-PDA ligation patients with, and without VCI. Pooled odds ratio was 26.02 (95% CI, 2.51 to 270.05) (P=0.006)