2017-18 HSC Section 3 Green Book

m a d s e n e t a l c t a f o r a e r o d i g e t s i v e t r a c t i n j u r y f o l l o w i n g p e n e t r a t i n g n e c k i n j u r y

Table 6 e Significance of surgical emphysema on CTA in identifying any ADTI when pneumothorax has been excluded. CT findings Patients with confirmed ADTI and no pneumothorax Patients without confirmed ADTI and no pneumothorax

CTA suggestive of injury total

30 (two with missile tract identified as through the pharynx and deep surgical emphysema)

70

Deep cervical emphysema

30

69

Mediastinal emphysema

14

31

CTA not suggestive of injury

2 (one of these with a healing blowing tracheal wound only had CTA done 10 d postsurgery. The other had an oral cavity injury and did not require surgery)

179 (28 of these CTA could not be reviewed for emphysema)

Total

32

249

Sensitivity

94.1% (32/[32 þ 2])

Specificity

71.9% (179/[179 þ 70])

Positive predictive value (PPV)

30% (30/[30 þ 70])

Negative predictive value (NPV)

98.9% (179/[179 þ 2])

ADTI ¼ aerodigestive tract injury; CTA ¼ computed tomography angiography.

if only clinically significant injuries were considered. These data are presented in Table 6 .

facial fractures and 30.8% spinal fractures diagnosed on CTA compared with only 2.1% and 4.2% of patients with PNI sec- ondary to an SW. CTA demonstrated hemo and/or pneumo- thoraces in 25% with PNI secondary to GSW and in 35.5% secondary to SW.

Other injuries identifiable by CTA in our study

Besides its value for the identification of vascular injuries and in the exclusion of ADTI, a number of bony injuries, soft-tissue injuries to the neck and chest injuries were diagnosed by CTA in our study as depicted in Table 7 . This additional value of CTA was particularly appreciated in patients were the mech- anism of injury was a GSW, as 28.8% of these patients had

Discussion

Although the selective approach to PNI using clinical assess- ment to determine the need for imaging is well documented, the actual algorithms around the choice of imaging remain controversial. 1 e 9 This is because there are a number of different organs, which may be injured, and traditionally different modalities were required to delineate each specific organ. Vascular injury is the most common injury associated with PNI; however, injuries to adjacent structures are also a problem. The associated injuries, which raise most clinical concern, are the injuries to the aerodigestive tract as these are associated with significant morbidity and mandate therapy, which frequently may be operative in nature. 24 e 26 The ongoing evolution of imaging and therapeutic modalities means that investigative algorithms will always be in a state of flux. Over the last decade CTA for PNI has emerged as a noninvasive alternative to CDA and a nonoperator-dependent alternative to color flow Doppler for the assessment of the vascular tree in the neck. Prospective and retrospective studies have consistently demonstrated that CTA has a high sensitivity and specificity for detecting arterial injuries. 10 e 14,16 e 19 What makes CTA so attractive is its ease as a procedure and its ability to detect injuries to adjacent nonvascular structures such as the spine, facial bones, soft tissue, and the aerodigestive tract. 10,11,14,17,18 If it can be shown that CTA reliably demonstrates all potential injuries in the neck, it will suggest that it can be used as a single defini- tive investigation and this may simplify clinical algorithms.

Table 7 e Other injuries identifiable by CTA in our study. Injury PNI second to

PNI second to SW (% of total SW)

GSW (% of total GSW)

n

52

331

Bony structures

Facial fractures

15 (28.8)

7 (2.1)

Spinal fractures

16 (30.8)

14 (4.2)

With associated cord injury (of the above)

6 (37.5)

5 (35.6)

Clavicle fracture

6 (11.5)

0 (0)

Rib fracture

4 (7.7)

5 (1.5)

Scapula fracture

2 (3.8)

2 (0.6)

Sternal fracture

0 (0)

1 (0.3)

Hyoid bone fracture

0 (0)

1 (0.3)

Soft tissue of the neck Thyroid injury Chest Hemopneumothoraces

1 (1.9)

3 (0.9)

13 (25.0)

116 (35.5)

CTA ¼ computed tomography angiography; GSW ¼ gunshot wound; SW ¼ stab wound.

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