Retropharyngeal hematoma after stellate ganglion block: Analysis of 27 patients reported in the literature

Development and validation of a new technique for ultrasound-guided stellate ganglion block

BACKGROUND AND OBJECTIVES

Although the stellate ganglion is located anteriorly to the first rib, anesthetic block is routinely performed at the C6 level. Ultrasonography allegedly improves accuracy of needle placement and spread of injectate. The technique is relatively new, and the optimal approach has not been determined. Moreover, the location of the cervical sympathetic trunk relative to the prevertebral fascia is debatable.

METHODS

Three-dimensional sonography was performed on 10 healthy volunteers, and image reconstruction was completed. On the basis of analysis of pertinent anatomy, a lateral trajectory for needle placement was simulated. Accuracy was tested by injection of methylene blue in cadavers. A clinical validation study was then conducted. A block needle was inserted according to the predetermined lateral path, and 5 mL of a mixture of bupivacaine and iohexol was injected. Spread of the contrast agent was verified fluoroscopically.

RESULTS

Image reconstruction revealed that the cervical sympathetic trunk is located posterolaterally to the prevertebral fascia on the surface of the longus colli muscle. The mean anteroposterior width of the muscle at the C6 level was 11 mm. The lateral approach does not interfere with any visceral or nerve structures. Anatomic dissection in cadavers confirmed entirely subfascial spread of the dye and staining of the sympathetic trunk. The contrast agent spread was seen in all patients between the C4 and T1 levels in a typical prevertebral pattern.

CONCLUSIONS

This study revealed that, at the C6 level, the cervical sympathetic trunk lies entirely subfascially. Subfascial injection via the lateral approach ensures reliable spread of a solution to the stellate ganglion.

Airway obstruction due to a pre-vertebral haematoma following difficult central line insertion--implications for ultrasound guidance and review of the literature

We describe a case of airway obstruction secondary to a large pre-vertebral cervico-mediastinal haematoma following failed attempts at insertion of an internal jugular central venous line. The need for a high index of suspicion to diagnose this injury and early aggressive intervention to manage it are outlined. The role of ultrasound guidance in preventing such a complication is reviewed, as well as other possible mechanisms of haematoma development.

The safety zone of percutaneous cervical approach: a dynamic computed tomographic study

STUDY DESIGN

A prospective study using computed tomography (CT) scans.

OBJECTIVE

To identify the structures at risk and the safety zone of a percutaneous cervical approach.

SUMMARY OF BACKGROUND DATA

A percutaneous cervical approach may injure the important structures of the anterior neck. However, the dynamic locations of vital structures and the structures at risk by routine trajectory have not been analyzed.

METHODS

Thirty patients were enrolled for this study. We obtained the CT scans of the cervical spine at each level of the intervertebral disc from C3-C4 to C6-C7, after manually pushing the airway in the same position and manner of discography. The patients ingested contrast materials for imaging of their digestive tracts and were injected intravenous contrast materials for imaging of vascular structures, just before obtaining images. We estimated the distances from the operator's fingertip to the digestive tract on the left side and to the carotid artery on the right side, at each level. The safety zone was determined by the sum of 2 distance calculations. We identified the anatomic structure at risk by simulated needle insertion toward the center of the disc through the safety zone.

RESULTS

At C3-C4, the safety zone was measured 18.9 +/- 6.6 mm. The superior thyroidal artery (STA) was located in the safety zone of C3-C4 in 86.7%. At C4-C5, the safety zone was measured 23.5 +/- 6.5 mm. The STA and the right lobe of the thyroid gland (TG) were located in the safety zone in 26.7% and 30%, respectively. At C5-C6, the safety zone was measured 33.7 +/- 6 mm. The TG was located in the safety zone of C5-C6 in 76.7%. At C6-C7, the safety zone was 29.2 +/- 4.5 mm. The TG was located on the approach plane in 90%.

CONCLUSION

The safety zone was wider at the distal level (C5-C6, C6-C7) than at the proximal level (C3-C4, C4-C5). The safest needle entry point should be between the pushing point of the airway and the pulsating point of the carotid artery. In addition, the needle should be approached toward the center of the disc. A percutaneous cervical approach allows a low risk of pharyngoesophageal structure injury and is considered a safe diagnostic technique in dynamic imaging studies.