Penetrating extracranial vertebral artery injuries

Background

Penetrating vertebral artery injuries (VAIs) are rare, difficult to diagnose, and pose a challenge to surgeons, given their complex anatomy and difficult surgical exposure. Due to the rarity of these injuries, few surgeons and trauma centers have developed a significant experience with their management.

Matas in 1893 reported 53 patients collected from the literature, which he divided into: endocranial aneurysms, 11; extracranial cerebral aneurysms, 20; and wounds or lesions of the vertebral artery, 22 patients. In his review, Matas credits Samson, who in 1824 described the first case of a gunshot wound to the vertebral artery in a patient that succumbed, and Maisonneuve, who in 1853 described the first successful ligation of a vertebral artery in the neck—also secondary to a gunshot wound in a patient that survived. The wartime incidence of these injuries is very low, with Makins reporting only three VAIs during World War I. No VAIs were reported during World War II or the Korean War. Greer in 2013 reported 11 VAIs from the recent Iraq and Afghanistan conflicts. Rich in 1975 reported 558 patients with 296 false aneurysms and 262 arteriovenous fistulas (AVFs) from the vascular injuries identified in the Vietnam Vascular Registry. Of these, two pseudoaneurysms and six AVFs of the vertebral artery (1.4% total) occurred as late sequelae.

In this chapter we review the incidence, clinical presentation, radiologic identification, angiographic and operative management, incidence of vertebral artery aneurysms/pseudoaneurysms, AVFs, and outcomes for these rare and complex vascular injuries, as well as provide an extensive review of anatomic exposures and surgical techniques required for their management to familiarize surgeons with limited experience with the management of these injuries.

Incidence

The incidence of penetrating VAIs remains difficult to calculate, given the rarity of these injuries and the paucity of data available in the literature. To determine the incidence of these injuries in the military arenas of warfare, we reviewed series beginning with World War I up to the current conflicts in Iraq and Afghanistan—Operation Iraqi Freedom and Operation Enduring Freedom—totaling 5,342 reported acute arterial injuries. Makins in 1919 reported three patients from World War I and Greer in 2013 reported 11 patients from the Iraq and Afghanistan conflicts, for a total of 14 acute VAIs, with an approximated calculated incidence of 0.3%, confirming that these injuries as very rare entities during wartime ( Table 1 ). Interestingly enough, Rich in 1975 reported 558 patients: 296 (53%) diagnosed with false aneurysms and 262 (47%) with AVFs, from the total number of vascular injuries recorded in the Vietnam Vascular Registry. From these two groups he identified two (0.3%) false aneurysms and six AVFs (1.07%) due to VAIs. However, these were late sequelae of unidentified VAIs.

To calculate the incidence of these injuries in the civilian population, we also reviewed large series reporting numbers of VAIs from penetrating neck injuries (PNI), as well as all available VAI-specific series and case reports. A total of 3226 PNI patients were identified, of which there were 946 vascular injuries (29%) of named cervical vessels. There were a total of 100 VAIs reported in these collected series for a calculated incidence of 3.1% ( Table 2 ). Recently, significant emphasis devoted to identification and treatment of blunt VAIs has diagnosed blunt injuries with a greater frequency than previously reported. Many of these injuries have been identified via CT angiography (CTA) and/or formal arteriography and are for the most part, primarily managed nonoperatively with anticoagulation and/or interventional radiology techniques. Herein, however, we chose to concentrate our efforts on penetrating extracranial VAIs as blunt VAIs are covered in other chapters in this text book.

Mechanism of injury

To determine mechanism of injury (MOI) and other relevant data, we reviewed the 100 patients with VAIs collected from the PNI series, with only 29 (29%) reporting their MOI, the majority of which (26) were gunshot wounds (see Table 3 ). Since most of the PNI series did not provide adequate data to meet our inclusion criteria, further analysis of these series was deemed noncontributory. A review of the VAI-specific series identified 324 patients, of which 303 (93.5%) reported MOI, the majority of which were gunshot wounds (see Table 4 ). A review of 37 individual case report series collected 38 patients (one case report described 2 patients), all of which had data reporting their MOI (see Table 4 ).

In order to determine the most common anatomic site (laterality) of VAI vis-à-vis right versus left, we reviewed the 13 vertebral artery-specific series along with 38 patients in the case report group (see Tables 4 and 5 ), collecting a total of 362 VAIs. Eight case series and one case report failed to specify anatomic site of injury. Information was available for 177 patients (49%), which was separated into 84 (47.5%) right and 92 (52%) left VAIs with a very slight predominance of left sided injuries. One (0.5%) injury was bilateral. The anatomic site of injury for 185 patients (51%) was not specified (see Table 4 ).