S. Goare1, E. Forrest1, J. Serpell1,2, S. Grodski1,2, J. C. Lee1,2 1The Alfred Hospital,Monash University Endocrine Surgery Unit,Melbourne, VICTORIA, Australia 2Monash University,Department Of Surgery,Melbourne, VICTORIA, Australia
Introduction: Routine pre-operative vocal cord (VC) assessment with laryngoscopy in patients undergoing thyroid surgery allows clear documentation of baseline VC function, aides in surgical planning in patients with preoperative palsy, and facilitates the interpretation of intraoperative neuromonitoring (IONM) findings. This has been the practice in our institution for the last 20 years. In this study, we aimed to determine the rate of pre-operative vocal cord palsy (VCP) in our patient cohort; to evaluate the associated risk factors for preoperative VCP; and therefore, build a case for a selective approach to pre-operative laryngoscopic VC assessment.
Methods: : This retrospective review study recruited patients from the Monash University Endocrine Surgery Unit database from 2000 to 2016. Patients who had a VC assessment by fiberoptic laryngoscopy prior to undergoing thyroid surgery were included. Case files were reviewed for potential indicators of VCP, including hoarseness and other symptoms, previous neck surgery, largest nodule dimension, and history of head and neck irradiation.
Results: Of the 5 279 patients who had pre-operative laryngoscopy, 36 (0.68%) patients were found to have a VCP. Of these, 16 had a nodule > 3.5 cm, 15 had a hoarse voice, 12 had previous neck surgery, and 5 had a malignant cytology. More than one risk factor was present in 11 of these patients. Furthermore, the first 3 of these features would account for all 36 patients with pre-operative VCP. Pre-operative knowledge of malignancy was associated with palsy in 5 patients. However, all of these 5 patients also presented with either a hoarse voice or a nodule > 3 cm. Therefore, malignancy by itself was not an indicator of potential palsy. Approximately two-thirds of the 5 279 included patients had none of these 3 features and also did not have a VCP. Therefore, using these 3 pre-operative factors (hoarseness, previous surgery, nodule > 3.5 cm) as selection criteria, up to two-thirds of our patients could do without a pre-operative laryngoscopy and no palsy would have been missed. As this is a retrospective study, these data need to be interpreted with that in mind.
Conclusion: Using this large dataset, we have established that a VCP is extremely unlikely in the absence of previous neck surgery, hoarseness, or a large nodule. Therefore, in the era of intraoperative neuromonitoring, where the recurrent laryngeal nerve can be directly assessed, we support a selective approach to pre-operative laryngoscopy using the aforementioned criteria.
