Re: “The importance of preoperative laryngoscopy in patients undergoing thyroidectomy: voice, vocal cord function, and the preoperative detection of invasive thyroid malignancy”

Letters to the Editors Re: “The importance of preoperative laryngoscopy in patients undergoing thyroidectomy: voice, vocal cord function, and the preoperative detection of invasive thyroid malignancy” To the Editors: The paper titled “The importance of preoperative laryngoscopy in patients undergoing thyroidectomy: voice, vocal cord function, and the preoperative detection of invasive thyroid malignancy” by Randolph and Kamani1 in the March 2006 issue of Surgery provides an important message concerning the utility of preoperative recognition of vocal cord (VC) palsy by laryngoscopy in patients undergoing thyroid operations, and using this information as a predictor for presence of invasive thyroid cancer. There are, however, a few issues we would like to discuss. The importance of preoperative evaluation of VC function in patients with diagnosed or suspected thyroid malignancy cannot be overemphasized. Indirect laryngoscopy is indeed the most practical means of diagnosing VC palsy. Besides identifying VC palsy due to recurrent laryngeal nerve (RLN) or laryngeal invasion by a thyroid malignancy, such an examination helps document patients with VC palsy of idiopathic origin or due to a previous neck operation, thus safeguarding the surgeon from potential litigation on these accounts. Yet, routine laryngoscopy before all thyroid operations remains controversial.2 Mere recognition of VC palsy cannot be taken as an indicator of RLN involvement by an invasive cancer, as suggested by the authors. VC palsy can occur even in benign and noninvasive thyroid disease, as also reported in the present paper. A more detailed work-up looking for invasive cancer in the presence of VC palsy can be reserved only for patients with a diagnostic or suspicious cytology. In their series, the authors report resection of the RLN in 55% of patients with invasive cancers. This rather high rate of RLN resection seems to be a reflection of the authors’ policy of sacrificing all paralyzed RLNs in the presence of invasive cancer, as outlined in the algorithm provided in the paper. A more conservative approach of preserving the RLN whenever techni-

cally possible without leaving gross tumors in patients with paralyzed vocal cord is known not to increase the local recurrence3 and provides a chance of recovery of VC function in some of the patients with well-differentiated thyroid cancers of follicular cell origin. Neck imaging with computed tomography (CT) and magnetic resonance imaging (MRI) in patients with suspected invasive thyroid cancers is a common practice. These imaging studies are useful, and the newer generation CT and MR, in the hands of experienced radiologists, are expected to provide information about invasive disease with an overall accuracy rate of up to 90%.4 The low rate of identification of an invasive thyroid cancer by CT or MR in the present series (in 3/15 patients only) seems a little out of place. Identification of VC palsy with CT is tricky and needs specific protocols. It is possible that CT identified the VC palsy in only 3 of 12 patients in the present series because the CT was not performed with the specific objective of evaluating VC function. Vivek Aggarwal, MS Gaurav Agarwal, MS, DNB, PDC (Endocr Surg) Department of Endocrine Surgery Sanjay Gandhi Postgraduate Institute of Medical Sciences SGPGIMS, Raebareli Road Lucknow–226014, India E-mail: [email protected]

References 1. Randolph GW, Kamani D. The importance of preoperative laryngoscopy in patients undergoing thyroidectomy: voice, vocal cord function, and the preoperative detection of invasive thyroid malignancy. Surgery 2006;139:357-62. 2. Jarhult J, Lindestad PA, Nordenstrom J, Perbeck L. Routine examination of the vocal cords before and after thyroid and parathyroid surgery. Br J Surg 1991;78:1116-7. 3. Nishida T, Nakao K, Hamaji M, Kamiike W, Kurozumi K, Matsuda H. Preservation of recurrent laryngeal nerve invaded by differentiated thyroid cancer. Ann Surg 1997;226:85-91. 4. Wang JC, Takashima S, Takayama F, Kawakami S, Saito A, Matsushita T, et al. Tracheal invasion by thyroid carcinoma prediction using MR imaging. Am J Radiol 2001;177:929-36. doi:10.1016/j.surg.2006.05.016

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