A preliminary study of simple voice assessment in a routine clinical setting to predict vocal cord paralysis after thyroid or parathyroid surgery

OBJECTIVE: To determine if a simple assessment of vocal cord function performed in a routine clinical setting can predict vocal cord paralysis on laryngoscopy in patients following thyroid or parathyroid surgery. METHOD: Prospective observational cohort study of patients undergoing thyroid or parathyroid surgery. Vocal cord function was assessed in terms of an abnormality of voice or cough reported by the patient or detected by the examiner. Laryngoscopy was performed by indirect mirror examination or fibreoptic nasopharyngolaryngoscopy. Examiners included otolaryngology consultants, registrars, senior house officers and a general practitioner with a special interest in otolaryngology. The patient was often examined by a different clinician before and after surgery. RESULTS: Eighty-six patients participated in the study between August 2003 and July 2004. Eleven had a change in their voice postoperatively and one patient had difficulty coughing. Six of these patients had a vocal cord paralysis. A further five apparently asymptomatic patients had a vocal cord paralysis. The positive predictive value of voice assessment for vocal cord paralysis was 55%. CONCLUSION: In a routine clinical setting where the assessment of vocal cord function is often reported by different clinicians of varying experience at each patient attendance, the assessment of a patient's voice following thyroid or parathyroid surgery is not adequately predictive of vocal cord paralysis on indirect laryngoscopy or fibreoptic nasopharyngolaryngoscopy. Further study is required to determine reasons for this.