What is the optimal depth for core-out toward the foramen cecum in a thyroglossal duct cyst operation?

The high recurrence rate of thyroglossal duct cyst operations is well documented. Sistrunk's operation is widely accepted as the best procedure to prevent recurrence. Nonetheless, the optimum depth of core-out is still not well documented. We previously reported a standard running pattern of the thyroglossal duct in an anatomical reconstruction study. In more detailed pathological studies, we have tried to determine the optimal depth for core-out toward foramen cecum and the optimal width of the hyoid bone to be resected. The following items were clarified. (1) Double the horizontal distance from midline to the most distant thyroglossal duct in front of the hyoid bone was 2.4 to 9.6 mm. (2) The length of the single duct above the hyoid bone which spreads into many ductuli as it approaches the foramen cecum was about 3 to 5 mm in 2- to 6-year old children. (3) The diameter of the thyroglossal duct at the level of the cranial top of the hyoid bone was 175 to 1,400 microns. Half of the examined cases were less than 500 microns, which may have rendered direct dissection impossible. Based on these studies, we propose: (1) that a minimum of 10 mm of the hyoid bone should be resected, and for the sake of safety, more than 15 mm is preferable; and (2) that the depth of the core-out should be less than 5 mm in young children to avoid the breakdown of the branched ductuli near the foramen cecum.