Vocal palsy increases the risk of lower respiratory tract infection in low-risk, low-morbidity patients undergoing thyroidectomy for benign disease: A big data analysis

Objectives: Thyroidectomy is the commonest operation that places normally functioning laryngeal nerves at risk of injury. Vocal palsy is a major risk factor for dysphonia, dysphagia, and less commonly, airway obstruction. We investigated the association between post-thyroidectomy vocal palsy and long-term risks of pneumonia and laryngeal failure.

Design: An N=near-all analysis of the English administrative dataset using a previously validated informatics algorithm to identify young and otherwise low-risk patients undergoing first-time elective thyroidectomy for benign disease. Information about age, sex, morbidities, social deprivation and post-operative and late complications were derived.

Main outcome measures: Between 2004 and 2012, 43 515 patients between the ages of 20 and 69 who had no history of cancer, neurological, or respiratory disease underwent elective total or hemithyroidectomy without concomitant or late neck dissection, parathyroidectomy or laryngotracheal surgery for benign thyroid disease for the first and only time. Information about age, sex, morbidities and in-hospital and late complications was recorded.

Results: Mean age at surgery was 46±12. There was a strong female preponderance (85%), and most patients (89%) had no recorded Charlson comorbidities Most patients (65%) underwent hemithyroidectomy. Late vocal palsy was recorded in 449 (1.03%) patients, and its occurrence was an independent risk factor for emergency hospital readmission (n=7113; Hazard Ratio 1.52; 95% confidence interval 1.21-1.91), hospitalisation for lower respiratory tract infection (n=944; HR 2.04; 95% CI 1.07-3.75), dysphagia (n=564; HR 3.47; 95% CI 1.57-7.65) and gastrostomy/tracheostomy placement (n=80; HR 20.8; 95% CI 2.5-171.2). Independent risk factors for late vocal palsy were age, burden of morbidities, total thyroidectomy, post operative bleeding, male sex, and annual surgeon volume <30.

Conclusions: There is a significant association between post-thyroidectomy vocal palsy and long-term risks of hospital readmission, dysphagia, hospitalisation for lower respiratory tract infection, and gastrostomy/tracheostomy tube placement. This adds weight to the need, from a thyroid surgical perspective, to undertake universal post-thyroidectomy laryngeal surveillance as a minimum standard of care, with a focus on post-operative dysphagia and aspiration, and from a medical/respiratory perspective, to initiate investigations to identify occult vocal palsy in patients who present with pneumonia, who have a history of thyroid surgery.