Surgery in the cervicothoracic junction with an anterior low suprasternal approach alone or combined with manubriotomy and sternotomy: an approach selection method based on the cervicothoracic angle
Authors: Teng Honglin , Hsiang John , Wu Chunlei , Wang Meihao , Wei Haifeng , Yang Xinghai , Xiao Jianru 
Published: September 2009

Object
The authors propose an easy MR imaging method to measure and categorize individual anatomical variations within the cervicothoracic junction (CTJ). Furthermore, they propose guidelines for selection of the appropriate approach based on this new categorization system.

Methods
In the midsagittal section of the cervicothoracic MR imaging studies obtained in 95 Chinese patients, a triangle was drawn among 3 points: the suprasternal notch (SSN), the midpoint of the anterior border of the C7/T1 intervertebral disc, and the corresponding anterior border in the CTJ at the level of the SSN. The angle above the SSN was specified as the cervicothoracic angle (CTA). The spatial position between the brachiocephalic vein (BCV), the aortic arch, and the CTA was also measured. Based on these measurements involving the CTA, 3 different patient-specific categorizations are proposed to assist surgeons with selection of the appropriate anterior approach to the CTJ. Three categories of operative approach based on whether the most caudal part of the lesion site was above, within, or below the area of the CTA were classified. The patients were divided into long- or short-necked groups based on whether their own CTA was greater than (long necked) or less than (short necked) the average CTA. Finally, a left BCV was called superiorly located when it coursed above the manubrium. The method was evaluated in 21 patients with spinal bone tumors in the CTJ to illustrate the measurement of both the CTA and the great vessels, and corresponding approach selections.

Results
In this series of 95 patients, the most common vertebra above the SSN was T-3, especially the upper one-third of T-3. The mean CTA was 47.64°. The left BCV was superior to the manubrium in 21.1% of the 95 cases, and 93.6% of the left BCVs were at the T-2 and T-3 levels. Type A and most Type B lesions could be addressed via a low suprasternal approach, or this approach combined with manubriotomy, if necessary. Type C lesions falling below the CTA will need alternative exposure techniques, including manubriotomy, sternotomy, lateral extracavitary, or thoracotomy. The spinal levels that could be exposed in the long-necked CTJ group were always 1 or 2 vertebral levels lower than those in the short-necked CTJ group during the anterior low suprasternal approach without the manubriotomy.

Conclusions
Imaging of the thoracic manubrium should be routinely included on MR imaging studies obtained in the CTJ. It is important for the surgeon to understand the pertinent anatomy of the individual patients and to determine the feasible surgical approaches after evaluating the CTA and vascular factors preoperatively. An anterior low suprasternal approach, or this approach combined with manubriotomy, is applicable in most of the cases in the CTJ. It should be cautioned that preoperatively unrecognized variations of the left BCV above the SSN might result in potential intraoperative trauma during an anterior approach.