We thank Drs Machens and Dralle for their insightful comments regarding our recent publication on initial vs reoperative central neck lymph node dissection for papillary thyroid cancer. We would like to address their critiques in order.
First, we agree that initial operation consisting of total thyroidectomy and central neck lymph node dissection represents “greater tissue exposure” than reoperative central neck lymph node dissection, which is more frequently a unilateral, targeted operation. However, we believe that their use of a correction factor of 2.3 to adjust for the number of sides exposed to risk is based on flawed reasoning. Drs Machens and Dralle are assuming that initial neck dissection is an equivalent operation to reoperative neck dissection, for which complication rates for both types of operation are reported per side explored (not per patient, as we have reported in our article). This, however, is not the case. The greater tissue exposure of an initial operation is due not only to the increased frequency of bilateral central neck lymph node dissections but also to the fact that total thyroidectomy is performed at the same time. Reoperative central neck dissection rarely involves thyroidectomy, and we believe this is one of the main reasons for our observed similar rates of complications for initial and reoperative central neck dissections (in essence, the risks associated with total thyroidectomy in initial operation are balanced out by the risks associated with the scarred field in reoperation).