Anatomy Study Of Anterior Surgical Approach For Cervicothoracic Junction

Part I Anatomy study of anterior surgical approach to cervicothoracic spine through partial 1st rib resectionObjectives:To study the method and range of exposion for a novel anterior surgical approach to cervicothoracic spine through partial 1st rib resection. Then to clarify the anatomic characteristics of associated important structures Meanwhile, to make assessment of the feasibility of this novel surgical approach.Materials and Methods:10 adult fresh-frozen cadavers(58-83 years, mean 74.1 year) were used for this study. An anterior approach to cervicothoracic spine through partial 1st rib resection was conducted on both sides respectively. The 1st Rib resection began from the outer edge of the sternum to the medial margin of subclavical vein, then inferior retraction of the parietal pleura and lung was performed to expose anterior aspect of upper thoracic spine. Identifying the range of exposure by combination of observation and X rays. We used a vernier caliper on cadavers to measure the following data:the distance from the outer boundary of sternum to subclavian vein on both sides; the distances from bilateral thoracic sympathetic trunk to the rib heads at levels of T1-T4. Compare the influence on the surgery from anatomical structures, like important arteries and veins, thoracic duct, sympathetic trunk, vagus nerve and so on. To observe the important structures and study the relationship between these anatomy structures and cervicothoracic spine. Then make assessment of the structures easy to damage in different vertebral segment and the complications conducting the approach.Results:By using the novel approach through partial 1st rib resection, satisfied exposure of anterior cervicothoracic spine can be made on different levels bilateral, mainly T1-4, and there is no injury to important nerve and vessels, such as azygos vein, sympathetic trunk, the superior vena cava, aortic arch and so on. T5 could be exposed on the right side in 5 of the cadaveric specimens. The distances from the outer boundary of sternum to subclavian vein were:left:7.56 ±0.453 (6.88～8.13) cm, right:7.55 ±0.460 (6.82～8.15) cm, P>0.05.The distance from bilateral thoracic sympathetic trunk to the rib heads vary from 4.9 to 6.3 mm, without significant difference on levels.Thre are very important vessels、nerves and thoracic duct around anterior cervicothiracic spine, including aortic arch, azygos vein, sympathetic trunk, the superior vena cava, vagus nerve, trachea, esophagus and so on. In process of exposion on the left, aortic arch, thoracic duct, sympathetic trunk have close relationship with cervicothoracic spine and they will be likely injuried. Whrea on the right, superior vena cava, azygos vein, recurrent laryngeal nerve should be pay attention to.Conclusion:The anatomy study show the approach tocervicothoracic spine through partial 1st rib resection allows a good access to the anterior aspect of cervicothoracic vertebrae bilaterally. The novel approach is feasible in consideration of exposion. In addition, there are many important structures around cervicothoracic spine, thre may be a lot of complications if the approaches are applied in clinic. So further studies are needed before clinical application.Part II Antomy study of anterior surgical approach via subtotal excision of sternal manubriumObjectives:To study the method and range of exposion for an anterior surgical approaches to cervicothoracic spine via subtotal excision of sternal manubrium. Then to clarify the anatomic characteristics of associated important structures of these the approach. Meanwhile, to make assessment of the feasibility of it.Materials and Methods:Prepare 7 adult fresh-frozen cadavers and make subtotal excision of sternal manubrium with sternoclavicular joint preserved. The osseous window is made from jugular notch upwardly to sternal angle downwardly, and between the boundary of sternal manubrium laterally. Then make blunt dissection of superior mediastinium to find the great vessels. Exposing the vertebrae of cervicothoracic through three different space:the space between branchiocephalic trunk and right branchiocephalic vein, the space between branchiocephalic trunk and trachea along with esophagus, the space between trachea along with esophagus and left common carotid artery. After complete the exposion, make clear the range of exposion of different space from proximal to caudal by means of bone landmarks or fluoroscopy. And then study the characteristics of approach-related important anatomical structuresResults:After subtotal excision of sternal manubrium to expose anterior of cervicothoracic spine, we found that the anterior of cervicothoracic vertebrae can be exposed through three spaces:the space between branchiocephalic trunk and right branchiocephalic vein, the space between branchiocephalic trunk and trachea along with esophagus, the space between trachea along with esophagus and left common carotid artery. The good realization is achieved by pulling the important structures including branchiocephalic trunk, branchiocephalic vein, left common carotid artery, esophagus and trache. The range of exposion of these three spaces varies each other, of which the the exposion extent of the space between right branchiocephalic vein and branchiocephalic trunk is the largest relatively. Also the exposion extent varies individually.Conclusion:The anatomy study show the approach tocervicothoracic spine through subtotal excision of sternal mamubrium allows a good access to the anterior aspect of cervicothoracic spine. The approach is feasible in consideration of exposion. However, the approaches through different space are limited in room for conduction. So further studies are needed before clinical application. In addition, there are many important structures around cervicothoracic spine, thre may be a lot of complications if the approaches are applied in clinic.