Penetrating Neck Trauma Calgary Emergency Medicine PowerPoint Presentation

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Penetrating Neck Trauma C McCrossin, R1

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Objectives Anatomy Clinical Features Diagnosis Management Disposition

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Not Covered: C-Spine injuries Blunt neck trauma

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Definition Penetrating neck trauma is any injury that penetrates through the platysma

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Zones of the Neck

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Neck Zones-The Basics Zone II is the most exposed and accessible to direct surgical visualization and easier vascular control Zones I and III have structures that lie deeper making diagnosis and management of vascular injury more difficult. Important to note which zone contains the injury and if the platysma is penetrated (without deep probing)

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Neck Zone I Proximal carotid artery Vertebral artery Subclavian artery Major vessels of the upper mediastinum Apices of the lungs Esophagus Trachea Thyroid Thoracic duct Spinal cord

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Neck Zone II Carotid artery Vertebral artery Larynx Trachea Jugular vein Recurrent laryngeal nerve Spinal cord

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Neck Zone III Distal carotid artery Vertebral artery Distal jugular vein Salivary and parotid glands Cranial nerves IX-XII Spinal cord

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Pretracheal layer of the deep cervical fascia inserts on the anterior pericardium putting patients with penetrating aerodigestive injuries at risk for mediastinitis

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Diagnosis

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Clinical Features Rarely do you have an isolated injury to the neck (polytrauma more common) Anatomical injuries to look for: Vascular Laryngotracheal Esophageal Neurological

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“Soft” Signs Hemoptysis/hematemesis Oropharyngeal blood Dyspea Dysphonia/dysphagia Subcutaneous air Chest tube air leak Non-expanding hematoma Focal neurologic deficits

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Vascular Injuries (Common Exam Question) “Hard” Signs of Vascular injury: Shock Airway obstruction Inspection Pulsatile bleeding Expanding hematoma Palpation Thrill Absent radial pulse Auscultation Bruit Ischemia Cerebral (stroke symptoms) Upper limb (pulse deficit)

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Vascular Injuries Morbidity and Mortality: Exsanguination Hematoma and airway compromise Direct vascular injury and subsequent occlusion Bullet embolization Air embolism Late complications: Traumatic aneurysm AV fistula formation (may present a few weeks after trauma)

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Laryngotracheal injuries Signs of Tracheal Injury Subcutaneous emphysema (most common) Respiratory distress Hemoptysis Hoarseness Air bubbling from wound (hard sign) Deformities of landmarks Deformity of neck landmarks Mediastinal air Stridor

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Esophageal Injuries Clinical Features Dysphagia Oral bleeding/blood in NG Subcutaneous emphysema Resistance to ROM of neck May be asymptomatic

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Esophageal Injuries Least common injury to occur Most common injury to miss Mortality secondary to mediastinitis

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Neurological Injuries Spinal cord Cranial Nerve Peripheral Nerve CNS Be wary of associated arterial injuries with neurological deficits because most nerves are located close to large arteries

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Cranial Nerves 1.Glossopharyngeal 2.Hypoglossal 3.Vagus 4.Sympathetic Trunk 5.Phrenic Nerve

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Diagnosis Physical Exam Vitals Evaluate patients for “hard” and “soft” signs of injury Radiology Mandatory CXR and Neck views CT Angio Angio U/S Esophagography Scopes Esophagoscopy (rigid/flexible) Laryngoscopy Bronchoscopy

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Physical Exam Will miss 1/4 vascular injuries with physical exam alone (all neck zones) Better at ruling out airway injuries Most commonly miss esophageal injuries

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X-Ray CXR to rule out pneumothorax, chylothorax, hemothorax Lateral neck films Can demonstrate retropharyngeal air, tracheal deviation Cervical spinal injuries

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Angiography Gold standard for evaluating possible vascular injuries Invasive Potentially therapeutic

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MR-Angiography Used for assessment of vascular injuries Not good for bony structures Limited use in trauma patient b/c of need for proper monitoring and MR-incompatible equipment

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Helical CT Angiography Highly sensitive and specific for vascular injuries (NPV 98%, PPV 100%) Trauma Reports Nov/Dec 2006 Cannot treat the vascular injury and patients may still require angiography Difficult to assess the subclavians Widely used in neck trauma

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Helical CT CT alone is a highly sensitive diagnostic tool Negative CT does not rule out aerodigestive injuries

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Helical CT Inaba et al 2006 evaluated the use of CT in penetrating neck trauma in all zones 91 patients (34 GSW, 57 Stab) Compared CT against a gold standard of surgery/followup/all other imaging CT was 100% sensitive, 94% specific No injuries were missed with 85% follow-up

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Endoscopy Flexible endoscopy is primary means to investigate laryngotracheal trauma (average FN rate of 20%) More difficult to evaluate esophagus and pharynx than the laryngotracheal system May require contrast swallow imaging to detect esophageal injuries in the cervical region (sensitivity reportedly as low as 60%) Rigid endoscopy is more sensitive but technically more difficult and not always available

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Color Flow Doppler Non invasive Highly operator dependent May not be available at night or on weekend Lots of artifacts (ie Bone) Difficult to examine smaller vessels Only real use is as an alternative in stable patients with zone II injuries

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Summary Of Investigations

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Management: The Debate Long historical debate over mandatory exploration and selective management Prior to WWII expectantly watching stable patients resulted in a mortality rate of up to 35% Mandatory exploration reduced mortality rates to 6% Mandatory exploration results in a 50-60% negative exploration rate However there is little morbidity or mortality with a negative surgical neck exploration Need to strike a balance that minimizes both mortality rates and the rate of negative surgical explorations

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Management Airway RSI is considered safe Breathing Beware of pneumo Hemothorax/chylothorax also possible Circulation Don’t clamp Direct pressure to control bleeding Exposure Look for other injuries Do not probe neck injury Disability C-spine precautions if indicated

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Quick word on airway RSI is safe Neck is a tight compartmentalized space which may appear ok externally but significant airway compromise can be secondary to edema or hematoma

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Management Approach (Common Exam Question)

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Zone I Managed selectively because of difficulty obtaining intra-operative exposure Investigations Arteriogram to exclude great vessel injury Bronchoscopy to identify laryngotracheal injuries Combination of esophagography and esophagoscopy to evaluate for potential esophageal injuries

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Zone I (cont.) Is routine arteriography mandatory for penetrating injuries of zone 1? 138 pts, 10 year retrospective study Results demonstrated CXR and PE have a NPP of 100% at ruling out arterial injury Conclude that routine arteriography may not be necessary Eddy et al 2000

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Zone II Controversial Region in stable patients Trend is towards selective management vs mandatory surgery Easiest zone to both diagnose injury and best for gaining adequate intraoperative exposure

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How Good is P/E at Detecting Zone II Vascular Injury? Prospective use of physical exam (P/E) in 145 patients with zone II injuries F/U included repeated P/E over 23 hours plus 2 week post injury F/U Use of “hard signs” to decide on surgery: Active bleeding, expanding hematoma, thrill over the wound, pulse deficit, central neuro deficit

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Role of Physical Exam alone in Zone II Vascular Injuries

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Zone II Vascular Injuries (cont.) Authors concluded that physical exam alone can be used to exclude significant vascular injuries in zone II with a FN rate comparable to angiography.

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Role of CT in Zone II Injuries Prospective; 42 patients with Zone II injuries All pts had CT, esophagography, then OR 2 esophageal injuries (out of 4) missed by P/E, CT and esophagography All patients with tracheal and carotid injuries were identified by CT alone Conclusions: CT has little impact on diagnosis and management Gonzalez et al 2003

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Zone II (cont.) The debate over mandatory OR vs selective management of zone II injuries is ongoing however most centers have adopted a selective approach Physical exam alone may be sufficient to exclude significant vascular injury CT may be beneficial at identifying bullet trajectory

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Zone III Vascular Injuries Require studies of the cerebral circulation, upper airway, and esophagus All symptomatic patients with zone III injuries require diagnostic evaluation of both esophagus and arteries

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Zone III Absence of hard signs reliably excludes surgically significant vascular injuries in zone III suggesting angiography is not necessary Hard signs in a stable patient should mandate angiography because these vascular injuries may be amenable to endovascular therapy Ferguson et al 2005

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Laryngotracheal Injuries 10% of penetrating neck injuries include a laryngotracheal injury Rarely are these injuries occult Mandatory laryngoscopy with any of the previous mentioned signs Bronchoscopy for symptomatic injuries in zones II and III

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Esophageal Injury Found in ~ 7% of penetrating neck trauma Combination of physical exam, endoscopy, and esophagography can reliably diagnose all significant injuries Demetriades et al 2001 Most of these injuries require EARLY operation to decrease morbidity and mortality secondary to mediastinitis

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Neurological Injuries 10% of asymptomatic patients with gunshot wounds to the trunk had associated spinal injury Actual prevalence of spinal cord and neurological injury is controversial but bad outcome if overlooked Approach varies depending on signs/symptoms and mechanism of injury

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Does Mech of Injury matter? Harry Whittington Why is his pic in my presentation?

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Shot in the neck by this evil man:

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Great example of penetrating neck trauma reaching all three anatomical zones!

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Ballistics Tissue penetration and trajectory dependent upon many different factors (muzzle velocity, bullet design, etc) therefore difficult to predict internal injury and imaging warranted (angio, CT angio) Gun-shot wounds to the neck are not absolute indications for exploration Demetriades et al 1996 CT is very useful at tracking path of bullet

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What should we be doing in Calgary? Zone I & III injuries: If stable and regardless if symptomatic or asymptomatic then triple scope (esophagoscopy/laryngoscopy/bronchoscopy + CT angio) Zone II injuries: If stable and asymptomatic then observe for 24 hours (no investigations), if any soft signs then triple scope plus CT angio or OR

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Practical Tips CXR to r/o Pneumo IV’s and Central lines on opposite side of injury Trendelenberg to decrease air embolism Ancef to decrease risk of infection (esp mediastinitis) Consult early

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The “Do Nots” Never clamp vessels (direct pressure) Don’t poke/probe (may release hematoma) Don’t remove impaled objects Don’t place an NG

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SUMMARY Does the injury penetrate the platysma? Management based on stable/unstable, zones, and presence of “hard” and “soft” signs RSI is considered safe Evidence suggests that physical exam is a powerful tool which can rule in and rule out significant vascular injury Imaging required in high velocity penetrating trauma

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Summary (Cont.) Angio is gold standard for vascular injuries, CT angio also highly sens/spec Esophageal injuries most commonly missed =>risk of mediastinitis (deep fascia anatomy)

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The End