Chapter 11 – Vertebral Artery Injuries




Abstract






  • The vertebral artery (VA) is the first cephalad branch of the subclavian artery. From a trauma surgery perspective, the VA is divided into three parts. Part I runs from its origin at the subclavian artery to C6, where it enters the transverse foramen. Part II courses in the bony vertebral canal, formed by the transverse foramen of C6 to C1. Part III runs outside the vertebral canal, from C1 to the base of the skull. The VA enters the skull through the foramen magnum, piercing the dura mater. It joins the contralateral VA to form the basilar artery, which is part of the circle of Willis.
  • The first part of the VA can be landmarked externally by the triangle formed by the sternal and clavicular heads of the sternocleidomastoid (SCM) muscle and the clavicle. It runs upward and backward between the anterior scalene and longus colli muscles, before entering the vertebral canal at the C6 level.
  • The carotid sheath is anterior and medial to the first part of the VA.
  • The external landmark of C6, where the VA enters into the vertebral canal and the second part of the VA begins, is the cricoid cartilage.
  • The VA is surrounded by a venous plexus.





Chapter 11 Vertebral Artery Injuries


Demetrios Demetriades , Morgan Schellenberg , and Nick A. Nash



Surgical Anatomy




  • The vertebral artery (VA) is the first cephalad branch of the subclavian artery. From a trauma surgery perspective, the VA is divided into three parts. Part I runs from its origin at the subclavian artery to C6, where it enters the transverse foramen. Part II courses in the bony vertebral canal, formed by the transverse foramen of C6 to C1. Part III runs outside the vertebral canal, from C1 to the base of the skull. The VA enters the skull through the foramen magnum, piercing the dura mater. It joins the contralateral VA to form the basilar artery, which is part of the circle of Willis.



  • The first part of the VA can be landmarked externally by the triangle formed by the sternal and clavicular heads of the sternocleidomastoid (SCM) muscle and the clavicle. It runs upward and backward between the anterior scalene and longus colli muscles, before entering the vertebral canal at the C6 level.



  • The carotid sheath is anterior and medial to the first part of the VA.



  • The external landmark of C6, where the VA enters into the vertebral canal and the second part of the VA begins, is the cricoid cartilage.



  • The VA is surrounded by a venous plexus.



General Principles




  • Most VA injuries can be effectively managed with angioembolization. Angiographic intervention is the preferred therapeutic modality for these injuries due to the difficult anatomy and complexity of the operative exposure. Operative management with direct surgical control of the bleeding is reserved for cases with severe active bleeding or if interventional radiology is not available.



  • Ligation or endovascular occlusion of the VA is tolerated well and rarely causes neurological deficits.



  • Gunshot wounds to the VA are often associated with spinal fractures and spinal cord injuries.



Special Surgical Instruments




  • Equipment for the operation should include a major vascular tray for trauma, periosteal elevator, and bone rongeurs.



Positioning




  • The patient should be positioned supine. If the cervical spine has been cleared, the head should be turned away from the injured side with the neck slightly extended. This can be aided by placing a folded towel between the patient’s shoulders.





Figure 11.1 Anatomy of the vertebral artery (VA). The VA is the first cephalad branch of the subclavian artery and is divided into three parts. The first part courses from its origin off the subclavian artery to C6, where it enters the transverse foramen. Part II runs in the bony vertebral canal between C6 and C1. The third part travels from C1 to the skull base.



Exposure of Part I of the VA



Incision




  • A supraclavicular transverse incision may be used on rare occasions for exposure of the proximal VA, outside the vertebral canal. This is a limited exposure and does not allow satisfactory exploration of the carotid sheath or the aerodigestive tract.



  • To accomplish this, begin by marking the sternal and clavicular heads of the SCM muscle. Perform a transverse skin incision, extending between the medial border of the sternal head and the lateral border of the clavicular head of the SCM muscle, approximately two fingerbreadths above the clavicle. Carry this incision through the platysma and identify the sternal and clavicular heads of the SCM muscle.








Figure 11.2 Supraclavicular skin incision for exposure of the first part of the right vertebral artery. A transverse skin incision is made about 2 cm above the clavicle, centered over the sternal and clavicular heads of the SCM muscle (a). Following the division of the platysma, the sternal and clavicular heads of the SCM muscle are exposed (b).



Exposure


Sep 4, 2020 | Posted by in EMERGENCY MEDICINE | Comments Off on Chapter 11 – Vertebral Artery Injuries
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