How to perform a lateral neck approach for penetrating neck trauma

Exposing the Sternocleidomastoid Anterior Edge

The aim is to expose the anterior surface of the sternocleidomastoid muscle and identify its medial border.

1. Controlled dissection with scissors is performed on the surface of the sternocleidomastoid muscle. The spinal accessory nerve penetrates the muscle in its upper third, so all dissection should happen on the surface of the muscle and not through it.

2. Once the anterior edge is clearly defined, retractors can be positioned to hold the superficial tissues aside, providing clear visualization of the muscle margin throughout the length of the incision.

Mobilizing and Retracting the Sternocleidomastoid

The aim is to retract the sternocleidomastoid laterally, providing exposure of the carotid sheath underneath.

1. Sharp dissection is used to free the sternocleidomastoid muscle along its medial edge.

2. The muscle edge is mobilized along the length of the incision. Superiorly, the spinal accessory nerve needs to be protected.

3. Perforating vessels entering the muscle should be coagulated or ligated before division.

4. Retractors are placed deeper until the sternocleidomastoid muscle can be fully retracted laterally. In a living patient, the carotid pulsation would guide the direction toward the carotid sheath.

Exposing the Carotid Sheath Proximally

The goal is to identify and expose the carotid sheath, which contains the major vascular structures of the neck.

1. The omohyoid muscle is identified in the caudal portion of the wound, running obliquely across the field.

2. The omohyoid muscle can be divided if proximal access to the carotid sheath is desired. This exposes the proximal internal jugular vein within the carotid sheath.

Opening the Carotid Sheath

The internal jugular vein (IJV) is exposed throughout the incision.

1. The carotid sheath is opened carefully, avoiding injury to the internal jugular vein.

2. The opening is continued cranially.

3. The carotid sheath is opened sufficiently when the internal jugular vein is visible throughout the incision.

Exposing the Internal Jugular Vein

The goal is to expose the internal jugular vein to be able to retract it aside to gain access to the common carotid artery.

1. The approach to the common carotid artery can be achieved either anterior or posterior to the IJV. In this case, both methods are shown and the vein is fully mobilized and looped for optimal exposure.

2. When dissecting around the neck veins, tissue traction should be gentle and sharp dissection is preferred over blunt spreading. Neck veins are fragile and tear easily. The repair is difficult after blunt stretch injury. Additionally, the vagus nerve runs within the same carotid sheath and must be carefully preserved during dissection.

3. The vein is now exposed and mobilized sufficiently to accommodate vessel loop placement and retraction.

Retracting the Internal Jugular Vein

The internal jugular vein can be retracted either anteriorly or posteriorly, providing access to the common carotid medial to it, without injuring the vagus nerve.

1. The method of retraction is a matter of preference; here, a vessel loop is used. The vessel must be adequately freed from surrounding tissues to allow safe passage of instruments without injuring the fragile vessel wall or adjacent carotid sheath structures.

2. When the vein is retracted anteriorly, the common carotid artery becomes clearly visible and the retrojugular route has been accomplished.

3. The vagus nerve is identified posteriorly inside the carotid sheath.

Exposing and Controlling the Common Carotid Artery

For carotid artery injuries, achieving proximal control is essential before addressing the injury site. The approach should be aimed proximal to hematoma, to the uninjured part. If possible, distal control should also be obtained, as backflow can be extensive.

1. The approach should be made sharply to the arterial surface to visualize the vasa vasorum, and after that, the sheath is opened more extensively.

2. The fundamental principle when dissecting the carotid artery is to manipulate it as little as possible and never grasp it directly with instruments. Gentle technique is essential to avoid intimal damage, dissection, or dislodging atherosclerotic plaque.

3. The common carotid artery has no branches before the bifurcation level, making exposure of this segment relatively straightforward, though careful technique with the instruments remains essential.

4. The vagus nerve is in close proximity and is kept protected at all times when working in the carotid sheath.

5. The artery is carefully encircled proximal to the injury area, and a vessel loop is passed around it.

6. A single loop provides gentle vessel control for mobilization and can be easily moved proximally as exposure is extended superiorly.

7. Here, a double loop is done, offering more secure control and allowing temporary occlusion without clamps when working on the injured area.
   If occlusion is performed, the patient should be heparinized to minimize the risk of embolic events affecting the central nervous system.

Exposing the Carotid Bifurcation

The goal is to expose the common carotid cranially to reach the level of the bifurcation. The typical level is at the superior border of the thyroid cartilage or C3–C4 vertebral level.

1. A good landmark for locating the bifurcation intraoperatively is to identify the facial vein branching from the internal jugular vein, which is typically located at the same level.

2. The internal jugular vein is exposed cranially until the facial vein is identified anteriorly.

3. As the vein is retracted aside, the caliber of the common carotid begins to widen, marking that the bifurcation level has been reached.

Identifying the External and Internal Carotid Arteries

The aim is to distinguish between the internal and external carotid arteries. This is critical for trauma management, as the internal carotid requires repair while the external carotid can be ligated if necessary.

1. The external carotid artery can be identified by the presence of branches, while the internal carotid normally has no extracranial branches in the neck.

2. The first branch is visible, the superior thyroid artery, confirming that the more medial vessel is the external carotid artery.

3. The confirmed internal carotid artery shows here the characteristic thicker proximal enlargement of the carotid sinus area. This is an extremely delicate area requiring utmost care during dissection. Stimulation of the carotid sinus may provoke vagal responses like bradycardia and hypotension.

Isolating and Controlling Carotid Arteries

Both carotid arteries are exposed further cranially to allow vessel loop control. The hypoglossal nerve should be protected.

1. The external carotid artery is gently secured with careful vessel loop placement.

2. After the loop has been placed, the fan-like appearance of the external carotid artery can be appreciated, with its multiple branches visible here. The main trunk has now been secured with the loop.

3. Due to limited space for controlling the internal carotid artery while protecting the hypoglossal nerve, the facial vein is ligated at this point to improve exposure and demonstrate the antejugular approach to the carotid arteries.

4. The vein is clamped proximally and distally, divided, and both ends are ligated.
   A transfixing ligature is used to secure the stump at the internal jugular vein side.

5. With the facial vein now ligated, better exposure of the bifurcation level is in this case achieved through the antejugular route.

6. This also reveals the hypoglossal nerve running close to the bifurcation.

7. It requires identification and careful preservation; here, a vessel loop is placed around it for a gentle hold before encircling the internal carotid artery.

8. The hypoglossal nerve can sometimes be located using the ansa cervicalis as a landmark, since its superior root travels with the hypoglossal nerve. The ansa cervicalis is a nerve loop innervating most strap muscles and runs along the carotid sheath. While ansa cervicalis preservation is preferred, it may be sacrificed for exposure, but the hypoglossal nerve must always be preserved.

9. With the hypoglossal nerve protected, the internal carotid artery can now be carefully encircled.

10. Vascular control of both the external and internal carotid arteries has been achieved, with the hypoglossal nerve protected.

Distal Exposure of the Internal Carotid Artery

The aim is to expose the internal carotid artery as far cranially as possible to demonstrate the maximal extent achievable through this approach. This is particularly relevant for high neck injuries near the skull base, where surgical access becomes increasingly challenging. While endovascular techniques are typically preferred for such injuries, understanding the anatomical limits of open surgical exposure remains essential.

1. Additional exposure can be obtained using several methods. Part of the salivary gland tissue has been mobilized here to demonstrate the cranial anatomy.
   If the parotid/submandibular gland is injured during the original trauma, the principle is to avoid excessive manipulation and allow ENT specialists to manage the injury. A drain should be placed to prevent fluid accumulation.

2. The posterior belly of the digastric muscle runs from the mastoid notch to the hyoid bone and can be divided to gain better access. If the muscle is divided, it should be done at the avascular tendinous part and the ends marked with sutures for repair upon closure.

3. The glossopharyngeal nerve is seen here coursing deep to the digastric muscle. It represents a critical structure in this higher region and must be protected when approaching the skull base.

4. At this level, the mandible creates significant anatomical obstruction. While vascular structures might remain visible, operative access becomes extremely limited in a trauma setting. Some additional space can be generated by subluxating the mandible anteriorly.

5. Recap of the exposed vascular structures in the lateral neck:

6. Proximally, this approach provides exposure down to the manubrial edge. The common carotid artery origin, branching from the brachiocephalic trunk alongside the subclavian artery, can be visualized through the lateral neck approach, but access to gain control of these vessels is typically achieved through endovascular methods or through sternotomy/supraclavicular incision.

Access to the Medial Structures

The lateral approach can be used to access the medial structures, exposing the trachea and esophagus for evaluation and treatment of potential injuries.

1. The thyroid gland is identified by the vasculature on its surface. It often obstructs access to the medial structures with the lateral approach, and typically requires mobilizing or, in some cases, resection.

2. Above the thyroid, access to the pharynx and larynx can be obtained if needed.

3. Posterior to the larynx/pharynx, the cervical spine is also accessible.

4. Anterior to the thyroid are the strap muscles. Access beneath these muscles is usually possible by identifying the appropriate tissue plane and proceeding in an avascular layer.

5. If the thyroid requires mobilization, the inferior pole vessels can be divided if needed for more exposure. Importantly, when dissecting posterior to the thyroid, the recurrent laryngeal nerve must be identified and protected from injury.
   On the right side, the nerve runs more medially than on the left side.

6. The tracheal cartilage rings can be palpated and they become visible once the thyroid is mobilized superiorly.
   The recurrent laryngeal nerve runs in the groove alongside the trachea and must be carefully preserved. Damaging it leads to vocal cord paralysis on the affected side and can affect swallowing.

7. The superior part of the esophagus can be approached bluntly posterior to the trachea, medial to the common carotid. If the patient has a nasogastric tube, identification is easier. The esophagus can be encircled and repaired through a lateral neck incision, but especially with complex injuries, bilateral exposure and/or a collar incision may be required.

Hemostasis and Closure

1. For extensive dissections and complex injuries, closed suction drains are placed to reduce postoperative swelling and provide early warning of potential postoperative bleeding.

2. Divided digastric or omohyoid muscles should be reconstructed, while the carotid sheath and sternocleidomastoid muscle require no suturing.

3. The actual wound is closed in two layers, starting with the platysma, which is closed using running 2-0 or 3-0 absorbable sutures in a single layer.

4. The skin can be closed with either intracutaneous sutures or running monofilament sutures. Staples are avoided because they are difficult to remove quickly if emergency re-exploration is needed.