Clinical Significance And Its Anatomy Observation On Anterior Approach Of The Upper Thoracic Vertebrae

【Objectives】1. To study the anatomic relationships between the upper thoracicvertebrae and correlated structures, including the recurrent laryngeal nerve,thoracic duct, blood vessels, so as to minimize the potential operative injuriesand the postoperative complication. To discuss the advantage anddisadvantage of different surgical approachs exposing the upper thoracicvertebrae and to elucidate the pertinent anatomical structures, explore theadvantages of this approach, we studied anatomy significance that we hope tofind some significant morphological characteristics helpful for surgery.2. The anatomy is studies of longus colli muscle and cervicalsympathetic trunk related to the anterior approach to the upper thoracicvertebrae.【Methods 】1.22 caderveric were used in this group, including 19 male and 2 female.An anterior surgical approach to the upper thoracic vertebrae has been madefrom two sides on 22 adult cadaveric specimens. A L-shaped skin incision isused, The manubrium sterni, as well as the upper third of the sternum, issplitted open. To measure the origin, course of the recurrent laryngeal nerve,thoracic duct, blood vessels, and relationships with the upper thoracicvertebrae on 22 adult cadaveric specimens.2. Recurrent laryngeal nerve were found between carotid sheath laterallyand trachea and esophagus medially. The visceral fasciae and its relation tothe recurrent laryngeal nerve were observed. The points where the recurrentlaryngeal enter the visceral fasciae were found and observed correspondingwith vertebral body level. The points where the laryngeal nerve cross themedial margin of common carotid artery were also observed correspondingwith vertebral body level.3. The distance between the medial sympathetic of the longus collimuscle and the prevertebral midline from C4toT4 was measured. Thedistance between the sympathetic trunk including the middle cervicalganglion and medial border of longus colli muscle, the distance between thesympathetic trunk and the prevertebral midline were recorded respectively .【Results】1. The recurrent point of the left recurrent laryngeal nerve locates at theupper one third of the T4 level with the right recurrent laryngeal nerve at theupper one third of the T2 level. The right recurrent laryngeal nerve reachesthe tracheoesophageal groove at the level of C6-7 disk in 55% and derivesfrom vagus nerve at the level of T1-T2. The left brachiocephalic vein is at T3in 55%. The aortic arch is at T3 and T4 in 80%. The anterior aspect of T3 canbe easily exposed through a modified anterior approach to the upper thoracicvertebrae in 55%.2. The thoracic duct was detected in all cadavers. The thoracic ductempties into the venous angle from T1 to T2.3. The main tributaries ofthoracic duct were determined and concentrated at upper thoracic segments(between third and fifth thoracic vertebrae) at the right side. We find thatanatomic variations of the thoracic duct are numerous and must beconsidered to avoid complications when doing surgery.3 The absence rate of the middle thyroid vein is 22.72%.4.Visceral fascia were intact in all of the 22 specimens .In 8 specimensthe laryngeal nerves entry to the visceral fasciae was at the level of C7-T1intervertebral disc, and 14 specimens at the upper half of T1 . In 8 specimensthe points where the laryngeal nerve cross the medial marnin of commoncarotid artery were at the level of upper half of T1 vertebral and 14specimens at the level of lower half of T1 vertebral. The left laryngeal nervehad no entry to the visceral fasciae at and above the level of T2.5. The distance between the medial border of the longus colli muscleand the prevertebral midline increased gradually from upper to lowercervical-thoracal levels which was(6.23 1.12) mm at C3,(7.11 0.16)mmat C4, (7.15 1.14)mm at C5, (7.12 1.19) mm at C6,( 8.10 0.15)mmatC7,( 8.76 2.13) mm at T1,(12.0 士 2.5) mm at T2. The distancebetween midline and sympathetic trunk was 20.10 2.10 mm in C3,22.10 4.10 mm in C4, 19.10 3.10 mm in C5, 15.10 4.10 mm in C6and 16.10 3.10 in C7. The distance from the medial border of thelongus colli muscle to sympathetic trunck was smaller at the C6 levels .6. Their relation is very close with between Mediastinum space andexposing the upper thoracic vertebrae.【Conclusion】This modified approach is adequate for the resection of upper thoracicvertebra. Although it is comparatively safer, care must be taken to avoidmajor vascular and nerve injury.