Technical Description
Appropriate patients are selected on the basis of having cytologically proven recurrent DTC that cannot be managed with ablative radioiodine and have small volume non-palpable recurrent disease in the neck at the site of previous surgery (either thyroid bed or neck dissection). The patient is subject to general anaesthesia, and prior to the skin incision the lesions are re-identified and confirmed using US. Between 0.5 - 2.0 ml of sterile activated charcoal suspension (Charcotrace®) is injected by an experienced Head and Neck radiologist under ultrasound guidance either into the lesion or the tissues immediately superficial to the target lesion. In addition, the lesion’s relationship to anatomical landmarks and depth from the skin are imaged and reported to the operating surgeon.
Where possible the previous thyroidectomy/neck dissection incision is re-utilised and dissection is performed carefully towards the lesion which is now easily identified visually due to the obvious charcoal staining of the tissues immediately anterior to it, and the surgeon’s knowledge of the site of the lesion relative to other anatomy. Once the lesion is excised, a repeat US can be performed intra-operatively to confirm excision before closure in equivocal cases. Recurrent laryngeal nerve monitoring is used if the lesion is in proximity to the nerve.
Fig.1 The recurrent lesion is easily identified due to the black hue of the charcoal dye anterior to its surface. Intra-operatively the lesion was impalpable but was confirmed by the presence of Charcotrace and pre/post resection ultrasound images, see figure 2.
Fig.2 Pre-operative (left hand image) ultrasound scan (USS) demonstrates an irregular hypoechoic lesion medial to the carotid artery and lateral to the tracheal wall (yellow arrow) consistent with recurrent papillary thyroid cancer. The post-operative (left hand image) USS demonstrates the lesion has completely resected. CA: Carotid Artery, IJV: Internal Jugular Vein, TL: Tracheal Lumen