Penetrating Trauma to the Neck: Utilizing Your Vascular Toolkit

INTRODUCTION

Penetrating injuries to the neck can result in devastating injury patterns secondary to the presence of vascular, aerodigestive, and nervous structures in close proximity.¹ Vascular structures are most commonly injured, and can have significant morbidity and a high mortality rate depending on the mechanism. Vascular injuries are suspected base on mechanism of injury, physical exam, violation of the platysma, and in some cases computed tomography (CT) imaging. The historical management of these injuries is based off the original description of zones of the neck by Monson at Cook County Hospital in 1969 and resulted in operative exploration of all Zone II injuries.² However, contemporary management has shifted to a “no-zone” approach, basing decisions on operative exploration or imaging on the presence of hard or soft signs of vascular trauma on physical exam.³ Soft signs of vascular trauma include non-expanding hematoma, neurodeficits, and history of blood loss on the scene. The hemodynamically stable patient with soft signs can be taken for CT angiography to evaluate for injuries. Patients with no signs of injury on CT, and a non-concerning trajectory, can be discharged from the emergency room.⁴ Hard signs of vascular trauma include pulsatile bleeding, expanding hematoma, and thrill on auscultation. Patients with hard signs should be taken directly to the operating room (OR) for exploration.⁵

Given the severity of these injuries, trauma surgeons must be familiar with neck anatomy, emergent management of vascular injuries, and the possibility of a concomitant tracheoesophageal injury. The operative management of any penetrating neck injury requires the surgeon to progress through multiple critical steps: 1) establishing an airway, 2) neck exploration, 3) choice of repair or damage control procedure. Once an injury is identified management follows universal vascular trauma principles: exposure, proximal and distal control, and lastly repair. This video techniques article will focus on the major vascular structures in the neck, relevant anatomy, describe approaches for repair, and offer damage control options. The approaches are demonstrated through supplemental digital online content. All videos are of procedures performed during teaching session on perfused fresh cadavers, in accordance with the policies of the West Virginia University Fresh Tissue Training Program.

PREOPERATIVE CONSIDERATIONS

Documentation of the patient’s neurologic exam prior to surgery is important. Signs of stroke or nerve palsy should be recorded prior to incision. Early communication with anesthesia will be important for the management of operative neck trauma. Establishing an airway is a critical first step, fiberoptic adjuncts and equipment for a surgical airway should be readily available during intubation. The OR should have vascular instruments, shunts, and arterial patches available (Figure 1). The patient is positioned with the neck rotated away from the side of injury. If a cervical collar is in place this should be removed. ^{6, 7} With isolated neck trauma, the arms are tucked to improve access to the operative field. The patient should be prepped to include the neck, chest, and groins. This allows for access to all pertinent anatomy and saphenous vein harvest if necessary. The patient should be draped with the ipsilateral ear and angle of the mandible exposed to serve as landmarks.

Figure 1:

Operating room checklist for carotid trauma.

TECHNIQUE

Initial Surgical Exploration and Anatomical Consideration

A complete neck exploration for trauma requires visualization of the carotid sheath and its contents, the esophagus, and the trachea. An incision along the anterior border of the sternocleidomastoid (SCM) is extremely versatile and can be extended depending on the concomitant injuries (Figure 2). For proximal injuries requiring great vessel access, the SCM incision can be extended to include a sternotomy. Division of the omohyoid muscle provides increased exposure to the proximal vessels and is a key step for exposing these injuries. For distal or skull base injuries, the incision can extended to the angle of the mandible and mastoid process.

Figure 2:

Multiple incisions allow exploration of the neck, the sternocleidomastoid (SCM) incision is the most versatile and is placed just anterior to the muscle. This can be extended with either a collar incision, a supraclavicular incision, or with a sternotomy.

After the initial incision is made, the dissection continues through the platysma until the anterior border of the SCM muscle is identified. The SCM is retracted laterally with the use of a self-retaining retractor to reveal the carotid sheath. The carotid sheath will need to be opened and explored. The facial vein is a useful landmark, originating from the internal jugular vein, it commonly overlies the carotid bifurcation, and can be ligated to improved exposure and prevent traction injury to the jugular vein. The common, internal and external carotid arteries are then dissected free from the internal jugular (IJ) vein (Figure 3). The external carotid artery (ECA) is readily identified by an early branch, the superior thyroid artery, contrary to the internal carotid artery (ICA), which does not contain branches within the neck. With the carotid bifurcation exposed, control of the common, internal and external carotid arteries should be quickly obtained with vessel loops or vascular clamps. (see Supplemental Digital Content 1, Video 1: Carotid Sheath Anatomy)

Figure 3:

Vessels loops encircle the common carotid artery (CCA), internal carotid artery (ICA), and external carotid artery (ECA). Note the superior thyroid artery coming from the external carotid artery (arrow). The facial vein has been ligated to improve exposure of the carotid bifurcation.

Knowledge of the nervous structures within the neck are critical to avoid iatrogenic injury. The ansa cervicalis often overlies the carotid vessels. This can be sacrificed for exposure, and used as a handle to assist in cephalad dissection along the ICA. The vagus nerve is found within the carotid sheath between the common carotid artery (CCA) and IJ vein. The hypoglossal nerve should be identified during dissection and is typically found crossing over the ICA, superior to the bifurcation and near the angle of the mandible. Excessive retraction against the hypoglossal nerve can lead to nerve palsy, sometimes confused for a post-operative stroke. Care must be taken when dissecting around the carotid bifurcation as this contains a collection of nerve endings known at the carotid body, which when irritated can lead to severe bradycardia. If bradycardia becomes problematic, injection of local anesthetic into the carotid body can blunt its response.

Once vascular control has been achieved any hematoma present with the neck should be explored. After identification of an injury attention can turn towards repair and complete exploration of the neck. For isolated vascular injuries systemic heparin should be utilized (100 units/kilogram). However, if the patient has a contraindication to systemic anticoagulation the repair can be completed with regional heparin injection into the affected vessel. For regional heparin, 5,000 units are diluted in 100mL saline and injected proximally and distally with blunt tipped syringes. Prior to suturing, a fogarty catheter is utilized proximally and distally.

Carotid Artery Injury

With vascular trauma wide exposure of the vessel is critical to identify the zone of injury. Debridement of any devitalized artery should be performed prior to any repair. Blast and projectile injuries often require larger areas of debridement and tend to cause destructive lesions. Lacerations secondary to stab wounds typically need only a small debridement.

Primary repair can be performed in the setting of a limited injury to the vessel, and more commonly with stab injuries. Small lacerations are primarily repaired with simple interrupted permanent monofilament suture. In the event of a complete transection, or injury with minor tissue loss, an end-to-end anastomosis can be performed. Any repair requiring clamping of the CCA or ICA is a candidate for carotid shunt use to maintain cerebral perfusion. The artery should be dissected and mobilized to provide a tension free repair. A running permanent monofilament suture is utilized for the anastomosis. (see Supplemental Digital Content 2, Video 2: End to End Anastomosis) More extensive injuries will require repair with either patch angioplasty or interposition graft, both of which we recommend performed with vein conduit in the setting of trauma due to the contamination and infection risk. However, if vein is unavailable, a PTFE graft can be sized to the CCA, usually 6 or 8mm is adequate.

Destructive injuries to the carotid system require special management. With any severe or flow limiting injury, a carotid shunt is utilized to temporarily restore cerebral blood flow. (see Supplemental Digital Content 3, Video 3: Carotid Shunt Placement) Argyle shunts are preferred for a damage control setting and should be secured proximally and distally with silk ties. When placing a shunt for damage control purposes, debridement of the vessel should be avoided during the initial operation to preserve vessel length for future definitive repair. For severe ECA injury the surgeon should consider ligation. While there is some historical record of ICA and CCA ligation, the risk of severe neurologic consequences is extremely high. However, ligation of the ICA or CCA should be considered in the case of a completed stroke secondary to injury. If prior imaging demonstrated cerebral ischemic changes, and no back bleeding is found on exploration, ligation of the damaged ICA can decrease the risk of future conversion to hemorrhagic stroke.

One consideration for a destructive injury to the ICA is the external to internal carotid artery transposition. This allows use of native vessel and precludes the need for vein harvest. After controlling the vessels, the ECA is divided as distally as possible to allow adequate length for transposition. The distal end is then suture ligated. With the ICA debrided, the ECA is transposed and an end-to-end anastomosis performed. (see Supplemental Digital Content 4, Video 4: Carotid Transposition)

Vertebral Artery Injury

Exposure of the proximal vertebral artery (VA) is obtained through a supraclavicular incision. (see Supplemental Digital Content 5, Video 5: Vertebral Artery Exposure) This is continued through the platysma, and division of the anterior scalene muscle is required. The surgeon should identify and preserve the phrenic nerve, superficial to the anterior scalene, prior to division of the anterior scalene muscle. The VA originates proximally from the subclavian artery and courses posteriorly. In the case of destructive injuries adequate vessel length for repair is difficult to obtain, and ligation is common. Unilateral injuries can generally be ligated without cerebrovascular injury. But, in 15% of cases the contralateral artery is diminutive, providing very little perfusion to the posterior system. Without preoperative imaging this can be difficult to determine, therefore every effort is made to preserve the injured artery. The distal VA is challenging to access surgically. With the advent of cerebral endovascular techniques, stenting or embolization may provide a quicker and less morbid option for the management of these injuries. While extremely helpful for the VA, endovascular techniques are contraindicated for carotid trauma due the real risk of unpredictable thrombosis.

Internal Jugular Vein Injury

Management of IJ vein injuries simplifies to primary repair or ligation. In the setting of small injuries primary repair is attempted with monofilament suture. With major tissue loss or ongoing massive hemorrhage, ligation of a unilateral IJ can be performed with minimal morbidity. In the event of bilateral IJ injury every effort must be made to repair one of the injured veins. Acute ligation of the bilateral IJ veins can lead to cerebral edema and elevated intracranial pressures.

SUMMARY

Injuries to the vasculature of the neck comes with a high risk of major morbidity and mortality. Familiarity with the anatomical considerations, exposure techniques, and options for repair are crucial to manage these injuries. After the initial exploration and hemorrhage control the surgeon should consider options for definitive repair or temporizing techniques. Damage control can be considered for both patient and surgeon factors. If a surgeon’s skillset in vascular anastomosis is limited, shunting provides an opportunity to temporize and obtain expert consultation, or transport the patient to a higher level of care.

Each vascular structure in the neck has unique properties for management and repair, but standard principles of vascular surgery apply to each structure. Exploration will require obtaining proximal and distal control to expose and an injury. Trauma to the CCA or ICA comes with the highest risk of morbidity and generally requires repair. Primary repair should be performed if possible, if not patch angioplasty or interposition graft are utilized. With major tissue loss, an external to internal carotid artery transposition may be required. Temporary shunting should be utilized during carotid repairs to preserve cerebral perfusion. Distal VA injuries are notoriously difficult to manage surgically, and are typically managed with endovascular techniques. Proximal VA injuries can be exposed and repair or ligated. Finally, primary repair of any internal jugular vein injury should be attempted but a unilateral vein can be ligated.

Supplementary Material

Supplemental Video File 1

SDC 1: This video demonstrates anatomic relationships between the contents of the carotid canal and critical nervous structures.

Supplemental Video File 2

SDC 2: An end-to-end anastomosis is demonstrated without spatulation. This technique can be used for trauma with minimal tissue loss and no size mismatch. Sutures placed at the 3 and 9 position are tied and then ran posteriorly and anteriorly to complete the anastomosis.

Supplemental Video File 3

SDC 3: An argyle shunt is utilized to restore cerebral perfusion after an internal carotid injury. For demonstration purposes the distal clamp has been omitted from the shunt.

Supplemental Video File 4

SDC4: An external to internal carotid artery transposition is performed after a destructive injury to the internal carotid artery could not be repaired without significant stenosis.

Supplemental Video File 5

SDC 5: Vertebral artery exposure through a supraclavicular exposure.