Risk factors for recurrent laryngeal nerve neuropraxia postthyroidectomy

Objective. Despite preservation of the recurrent laryngeal nerve (RLN), transient vocal cord paralysis (VCP) occurs after 1.2% to 10.9% of thyroidectomies. The objective of this study was to study risk factors for transient VCP after thyroidectomy.Study Design. Prospective cohort study.Setting. Academic teaching hospital.Subjects and Methods. Two hundred fifteen consecutive thyroid surgeries performed by a single surgeon. All patients underwent preoperative and postoperative laryngoscopy. Patients with preexisting VCP or without postoperative laryngoscopy were excluded. Clinical and operative data were recorded prospectively at the time of thyroid surgery. The association between possible risk factors and occurrence of postoperative transient VCP was studied.Results. Six patients were excluded (2 with preexisting VCP and 4 without postoperative laryngoscopy). There was 1 intentional sacrifice of an RLN and 1 unintentional RLN transection. Of the remaining 322 RLNs at risk, 15 (4.7%) had postoperative VCP. Operative findings of cancer invading the RLN requiring sharp dissection to separate the nerve (P =.006) and operative findings of RLN extensively draped along the thyroid or intimately associated with the thyroid parenchyma at Berry's ligament (P =.03) were significantly associated with VCP. Revision surgery (P =.06) trended toward significance. Malignancy, central compartment neck dissection, extralaryngeal RLN branching, hyperthyroidism, and retrosternal extension were not significant. Of cases with follow-up laryngoscopic documentation of vocal function, 85% (11/13) showed full resolution of VCP, with 1 further case showing partial recovery.Conclusion. Invasive cancer and variants in the anatomic course of the RLN are risk factors for transient VCP after thyroidectomy.