Preoperative Localization of Neck Recurrences from Thyroid Cancer: Charcoal Tattooing Under Ultrasound Guidance

Background: Reoperation for thyroid cancer recurrence is a surgical challenge in previously dissected necks, and there is a need for a reliable procedure for surgeon guidance. In this study, the usefulness of preoperative charcoal tattooing for surgical guidance was evaluated. Methods: From July 2007 to May 2010, 53 patients (40 females; M-age=44 years, range 19-76 years) were prospectively included for preoperative localization of neck recurrences from differentiated (n=46) or medullary thyroid cancer (n=7). Preoperative cytological assessment was performed for at least one lesion in each patient. Ultrasound (US) imaging was performed with high-frequency probes (8-14 Mhz). Micronized peat charcoal (0.5-3 mL) was injected under US guidance using a 25 gauge needle, 0-15 days preoperatively. Results: A total of 106 lesions were selected for charcoal tattooing. Of these, 101 had been tattooed, and 102 were removed (85 metastases, 17 benign on pathology). The tolerance of charcoal injection was good in all but three patients. A mean volume of 1 mL of charcoal was injected with a mean of two targets per patient. Charcoal labeling facilitated intraoperative detection in 56 "difficult" lesions (i.e., small size, dense fibrosis, anatomical pitfalls), and charcoal trace facilitated intraoperative guidance in 17 lesions. Feasibility and usefulness rates were 83% and 70.7% respectively. Conclusion: These findings suggest that charcoal tattooing under US guidance is an easy to implement, safe, and useful procedure for surgeon guidance in neck reoperation for thyroid cancer.