Factors influencing the length of the incision and the operating time for total thyroidectomy

The incision used for thyroid surgery has become shorter over time, from the classical 10 cm long Kocher incision to the shortest 15 mm access achieved with Minimally Invasive Video-Assisted Thyroidectomy. This rather large interval encompasses many different possible technical choices, even if we just consider open surgery.The aim of the study was to assess the correlation between incision length and operation duration with a set of biometric and clinical factors and establish a rationale for the decision on the length of incision in open surgery.

Ninety-seven consecutive patients scheduled for total thyroidectomy were prospectively evaluated. All operations were performed by the same team and the surgeon decided the length of the incision according to his personal judgement. Patients who had previously undergone neck surgery were excluded.

The length of the incision was strongly correlated with gender, thyroid volume, neck circumference and clinical diagnosis and weakly correlated with the body mass index. Operation duration was only weakly correlated with gender and neck circumference. Multiple linear regression revealed that the set of factors assessed explained almost 60 % of the variance in incision length but only 20 % of the variance in operation duration. When patients were classified according to the distribution of their thyroid volume, cases within one standard deviation of the mean did not show a significant difference in terms of operation duration with incisions of various lengths.

Although thyroid volume was a major factor in driving the decision with respect to the length of the incision, our study shows that it had only minor effect on the duration of the operation. Many more open thyroidectomies could therefore be safely performed with shorter incisions, especially in women. Duration of the operation is probably more closely linked to the inherent technical difficulty of each case.