Anatomic Study Of Thyroid Blood Vessels Under Laparoscopy Via Breast Approach

[OBJECTIVE]A careful anatomic study of thyroid blood vessels was performed, either by observing specimens of cadavers or by observation during laparoscopic thyroidectomy(LT) approached by breast method.This study aims to provide statistic and anatomic evidence for exposure and managements of thyroid blood vessels during the procedures,so as to decrease the chance of intraoperative hemorrhage or damage of neighboring structures.[METHOD](1) 20 preserved adult cadavers were used in the study to observe the thyroid blood vessels of their morphology,pathway,and relationship with neighboring structures.Branches and pathway of the vessels were measured and documented,followed by statistic analysis.(2) Thyroid vessels were identified and observed during 75 cases of LT while the procedures were recorded.External diameters(ED) of the arteries were measured and documented under laparoscopy.[RESULTS]1.Results obtained by dissection of cadavers- Origins,pathways and entrances of superior/middle/inferior thyroid veins as well as superior/inferior thyroid arteries were observed in the 20 cadavers.Content within the carotid sheath was also identified.- ED of inferior thyroid artery(ITA) at its origin=2.13±0.12 mm.- Relationship between ITA and recurrent laryngeal nerve(RLN) was observed: (LEFT) 17 cases of RLNs being posterior to ITAs,3 cases of RLNs being anterior to ITAs;(RIGHT) 13 cases of RLNs being anterior to ITAs,3 cases of RLNs being posterior to ITAs,3 cases of intersections of RLN and ITA. Differences between the results of left side and right side are of statistic significance(P＜0.05).- ED of superior thyroid artery(STA) at its origin=2.00±0.13 mm;Distances between origin of STA and the upper pole of thyroid=29.45±1.79 mm;ED at bifurcation point=1.91±0.12 mm;ED of the anterior branch=1.59±0.13 mm;ED of the posterior branch=1.61±0.13 mm.- 85%of the extralaryngeal branch of RLN located lateral to ITA while 15%of the extralaryngeal branch of RLN located posterior to ITA.2.Results obtained by direct observation under laparoscopy during thyroidectomy- No prosternal vessels were observed being＞1mm in ED.- In the anterior triangle of the neck,retrosternal entrances of the anterior jugular veins of two sides could be identified in each case,ED=3±0.13 mm.- Specific morphology of thyroid vessels and carotid sheath under the vision of laparoscopy could be observed in every case.- Occurrence rate of thyroid ima artery is 9.3%,ED=0.7±0.14 mm.- ED of branch of inferior thyroid vein:1.08±0.15 mm of thyroid mass, 1.24±0.17 mm of hyperthyroidism withⅠ°thyroid enlargement,1.56±0.24 mm of hyperthyroidism withⅡ°thyroid enlargement,2.34±0.15 mm of hyperthyroidism withⅢ°thyroid enlargement,Largest ED=2.0 mm. Differences of EDs among the four mentioned above are of statistic significance(P=0,000＜0.05).- ED of branch of ITA:1.41±0.17 mm of thyroid mass,1.71±0.2 mm of hyperthyroidism withⅠ°thyroid enlargement,2.10±0.11 mm of hyperthyroidism withⅡ°thyroid enlargement,1.92±0.12 mm of hyperthyroidism withⅢ°thyroid enlargement,Largest ED=2.6 mm. Differences of EDs among the four mentioned above are of statistic significance(P=0,000＜0.05).- ED of branch of middle thyroid vein:1.85±0.15 mm of thyroid mass, 2.14±0.11 mm of hyperthyroidism withⅠ°thyroid enlargement,2.34±0.1 mm of hyperthyroidism withⅡ°thyroid enlargement,3.01±0.11 mm of hyperthyroidism withⅢ°thyroid enlargement,Largest ED=3.4 mm. Differences of EDs among the four mentioned above are of statistic significance(P=0,000＜0.05).- ED of branch of superior thyroid artery:2.28±0.17mm of thyroid mass, 2.91±0.20 mm of hyperthyroidism withⅠ°thyroid enlargement,3.18±0.15 mm of hyperthyroidism withⅡ°thyroid enlargement,3.47±0.14 mm of hyperthyroidism withⅢ°thyroid enlargement,Largest ED=3.7 mm. Differences of EDs among the four mentioned above are of statistic significance(P=0,000＜0.05).[CONCLUSIONS]1.Morphology of thyroid vessels was observed being different from that of conventional open surgery.2.In cases of thyroid tumor,Ⅰ°thyroid enlargement,Ⅱ°thyroid enlargement, andⅢ°thyroid enlargement,EDs of vessels are different and the result is of statistic significance,while ED of vessels ofⅢ°thyroid enlargement was the largest and that of thyroid tumor being the smallest.This could be related to the amount of blood flow in the thyroid gland.3.Method of thyroid vessels exposure and identification under laparoscopy via breast approach is being different from that of conventional open surgery. Harmonic scalpel achieves adequate and effective hemostatsis.