APPENDIX C: CERVICAL VASCULAR INJURY

CAROTID ARTERY

- Recommendations: Repair.
- Utility of temporary shunt: High (low probability of shunt thrombosis and restores flow to the brain quickly)
- Method/Conduit: Vein patch or vein interposition graft.

Pearls

- Zone I cervical injuries are best approached with median sternotomy for ample proximal exposure.
- Early control of common carotid with umbilical tape/Rummel or DeBakey clamp.
- 3 Fr Fogarty with 3-way stopcock is useful to occlude internal carotid back bleeding.
- Shunt and augment mean arterial pressure during carotid repair to perfuse brain.
- Equipment: Weitlaner or Cerebellar self-retaining retractors, Argyle or Sundt shunts, and vascular clamps such as angled DeBakey clamp, profunda clamp, Kitzmiller clamp. Javid clamp.

#### Carotid Interposition with Shunt

Step 1: Place shunt into internal carotid (or distal carotid) and secure with Javid clamp or Rummel; allow back bleeding.

Step 2: Place the shunt through the lumen of the vein graft.

Step 3: Insert shunt into proximal carotid and secure with Javid clamp or Rummel.

Step 4: Restore of forward flow through the shunt then perform the distal vein graft anastomosis using 6-0.

Step 5: Start the proximal anastomosis to the common carotid with 6-0 Prolene.

Step 6: When the anastomosis is nearly completed, the shunt is removed through the remaining anastomotic opening.

Step 7: Remove the proximal aspect of shunt from the common carotid and observing back bleeding from the shunt in the internal carotid.

*Care should be taken to ensure the vein graft is reversed to negate the function of the venous valves. Vein valves may inhibit back bleeding through the vein graft.

Most carotid injuries result from penetrating wounds and result in hematoma. Indications for operation are bleeding or injury with interrupted flow (i.e. occlusion). When feasible, contrast CT should be performed for neck wounds. CT aids in the triage for urgent operation, improves operative planning and images the brain as a baseline. Although a selective approach to exploration of Zone II neck wounds is acceptable, if a carotid injury is identified, the neck should be explored, and an attempt made to repair. The exceptions are blunt injury resulting in carotid occlusion greater than 12 hours or a Zone III injury not accessible by standard techniques.

Exposure of the carotid artery is through a generous incision coursing anterior to the sternocleidomastoid and facilitated by a roll under the shoulders, extension of the neck and turning of the head away from the injury. The platysma is divided, and the sternocleidomastoid muscle reflected posterolaterally. The internal jugular vein is carefully dissected and mobilized laterally, exposing the carotid artery. The carotid is exposed proximal to the hematoma and controlled with an umbilical tape into a Rummel device (i.e. red rubber catheter). In the absence of uncontrolled bleeding, there is no need to tighten the Rummel; but having it in place gives one this option and allows for securing the proximal end of a temporary shunt.

The dissection proceeds distal into the zone of injury. If bleeding is encountered the Rummel may be cinched or a clamp (angled DeBakey) slid proximal to the umbilical tape using it to pull the carotid up into the clamp, thereby avoiding injury to the vagus nerve. Back bleeding from the internal carotid artery is a favorable sign and can be controlled with a small clamp or a (3 Fr) Fogarty inserted into the internal and inflated using a 1cc syringe and 3-way stop-cock to maintain inflation. The external carotid artery is controlled with vessel loops or ligated. If the internal and common carotid arteries are controlled above and below the injury, a temporary shunt can be placed to maintain perfusion while the injury is identified, and options considered. First, the shunt should be placed into the internal carotid artery and secured with a vessel loop or small Javid shunt clamp allowing back bleeding through the shunt. To secure the proximal shunt, an angled DeBakey is placed proximal to the umbilical tape and Rummel device. Then in sequence, the shunt is placed in the common carotid through the Rummel which is partially tightened around the shunt. As it is advanced deeper (more proximal) into the common carotid, the DeBakey clamp is slowly opened allowing the shunt to pass while the Rummel is tightened down fully securing the shunt in place. Alternatively, the common carotid artery can be controlled with fingers as the shunt is inserted proximal and the Rummel synched down. If available, Javid shunt clamps can be used to occlude the artery around the shunt instead of the Rummel device. A similar technique can be utilized with vessel loops to secure the shunt.

Repair of carotid artery injuries most commonly requires placement of an interposition saphenous vein graft, although primary repair or vein patch angioplasty can be performed for less severe injuries. To perform the interposition graft over the shunt, the proximal end is removed using the DeBakey clamp to again occlude the common carotid proximal to the Rummel. The vein graft is next placed over the shunt (i.e. shunt in the vein graft lumen). The proximal shunt is reinserted into the common carotid and secured with the Rummel using previously described sequence. After flow is restored in the shunt, the distal vein graft anastomosis is performed using 6-0 Prolene to the edge of the normal internal carotid. Next the proximal anastomosis to the common is started also with 6-0 Prolene. When the anastomosis is nearly completed, the shunt is removed through the remaining anastomotic opening, first removing the proximal from the common carotid and observing back bleeding from the shunt in the internal carotid. Finally, the shunt is removed from the internal and the vein graft flushed generously with heparinized saline and the anastomosis completed. Alternatively, the reconstruction can be performed without a shunt, however, this exposes the ipsilateral hemisphere to prolonged ischemia. Regardless of whether a shunt is used, the mean arterial pressure should be kept above 90mmHg during the repair to optimize cerebral perfusion. In more experienced surgical hands, measuring of an internal carotid stump pressure with SBP >50mmHg indicates intact Circle of Willis and collateralized hemispheric flow, allow easier repair of the carotid injury with interposition.

Alternatively, the reconstruction can be performed without a shunt, however, this exposes the ipsilateral hemisphere to prolonged ischemia. Regardless of whether a shunt is used, the mean arterial pressure should be kept above 90mmHg during the repair to optimize cerebral perfusion.

If no other life-threatening injuries are present, a small amount (50u/kg) of systemic heparin is recommended along with generous flushing of the repair with heparinized saline to prevent platelet aggregation and clot formation. Ligation of the internal carotid artery is an acceptable damage control maneuver to stop hemorrhage but has an acute stroke rate of 30-50% according to historic data, with more recent data showing a stroke rate of 100% after ligation due to penetrating trauma.1

VERTEBRAL ARTERY

- Recommendations: Ligate
- Utility of temporary shunt: None
- Method/Conduit: N/A

Pearls

- Bleeding vertebral artery injuries are ligated with no role for reconstruction in theater.
- Vertebral artery occlusions are managed with anticoagulation if it is not contraindicated.
- Endovascular embolization is an option if injury is not accessible by standard exposure.

Repair of vertebral artery injuries in wartime is extremely rare and most commonly bleeding from this vessel is ligated as a matter of necessity during neck exploration. Alternatively, vertebral artery injury (occlusion or extravasation) can be discovered on a contrast CT scan. There should be a high index of suspicion for this injury with cervical spine fractures. In instances of acute vertebral artery occlusion, anticoagulation is recommended to reduce the risk of posterior circulation stroke although the clinical evidence to support this is limited. If associated injuries preclude use of systemic heparin, then antiplatelet therapy should be initiated.

JUGULAR VEIN

- Recommendations: Selective repair
- Utility of temporary shunt: None
- Method/Conduit: Lateral venorrhaphy, vein patch or saphenous vein

Pearls

- Significant jugular vein injuries can be ligated without adverse effects.
- Repair of jugular injuries should be considered in the setting of TBI with elevated ICP.
- Repair instead of ligation of jugular vein injuries may be indicated in instances of associated closed head injury to reduce intracranial pressures, although little data exists to support this practice. Minor jugular vein injuries can be repaired by lateral suture repair (venorrhaphy) while patch angioplasty or interposition vein graft are options for more extensive injuries. Operative exposure of the jugular vein is the same as that described for the carotid artery.

REFERENCE

Sullivan PS, Dente CJ, Patel S, et al. Outcome of ligation of the inferior vena cava in the modern era. Am J Surg 2009;199:500-6.