Head and Neck Trauma Chapter 10 HEAD AND NECK TRAUMA † ‡ RYAN KENEALLY, MD*; MICHAEL SHIGEMASA, MD ; AND ARTHUR R. MIELKE, MD, MPH INTRODUCTION CERVICAL SPINE INJURIES Epidemiology and Injury Patterns Airway Management Radiologic Assessment Steroids HEAD TRAUMA Assessment and Monitoring Management SUMMARY *Lieutenant Colonel, Medical Corps, US Army; Assistant Professor, Department of Anesthesiology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814 †Captain, Medical Corps, US Army; Anesthesiologist, Department of Anesthesia, Walter Reed National Military Medical Center, 8901 Wisconsin Av- enue, Building 9, Bethesda, Maryland 20889 ‡Captain, Medical Corps, US Army; Physician, Department of Anesthesia, Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Building 9, Bethesda, Maryland 20889 121 Combat Anesthesia: The First 24 Hours INTRODUCTION Injury to the head and neck has always been a War II. Close attention to the principles of resuscitation major cause of morbidity in military casualties. The combined with advances in surgical and intensive care principles for dealing with these injuries were defined have markedly improved the outcome from neurologi- in the work of Major Harvey Cushing during World cal combat injury. CERVICAL SPINE INJURIES Epidemiology and Injury Patterns for a cervical spine fracture is the lower cervical region (39% at C6 or C7).9 The vertebral body is the most Cervical spine injuries (CSIs), which include bony common location of a fracture. Injury to the spinal and ligamentous injuries to the spine and spinal cord can result from fractures or ligamentous disrup- cord injuries with or without a detected fracture, are tion. Axial-load injuries are seen in diving accidents a common complication of acute traumatic events. among the civilian population, but may also occur in CSI sometimes occurs with other major injuries, but the combat environment; a C1 fracture (Jefferson burst other major injuries nearly always accompany CSI. fracture) can result from an axial load and may cause The estimates of cervical spine trauma or spinal cord neurologic damage directly or as a result of damage injury in civilian trauma patients has ranged from less to the vertebral arterial system. Flexion injuries can than 0.41%1 to 4.3%2 to 6%,3 and the incidence of CSI lead to anterior cord syndrome, which may result in varies with mechanism of injury. Rhee et al found a quadriplegia and the loss of pain and temperature three-fold higher risk of a CSI after gunshot wounds sensation. Extension injuries can also occur from rapid compared to blunt trauma, and a 3.5-fold lower risk of deceleration injuries. Neurologic assessment should a CSI among stab-wound victims compared to blunt- focus on motor and sensory function to determine a trauma victims.1 deficit and the level of injury. Victims of direct injuries to the neck carry a higher risk for a CSI. One study found a 12.1% rate of CSI Airway Management after a cervical gunshot wound, and a 1.5% rate of CSI after a cervical stab wound.4 An earlier study found a For patients with known or possible CSI, provide similar rate for CSI among patients with penetrating a patent and secure airway and avoid the secondary neck trauma.5 Data from combat-wounded service insult that can result from hypoxia or hypoperfusion; members in Iraq and Afghanistan suggests CSI is minimize or prevent further neurological insult that common with penetrating neck injuries sustained in can result from mechanical forces. Airway support combat. Just over 22% of 90 patients with penetrating may be needed before CSI can be assessed or ruled neck injuries seen at a British combat hospital were out. If a patient must be intubated prior to a full cervi- found to have CSI.6 A US study found a 30% rate of cal spine evaluation, providers should proceed using CSI after patients sustained penetrating neck wounds. manual inline stabilization (MILS) and rapid-sequence This evidence suggests combat-related penetrating induction if successful intubation is anticipated. If intu- neck trauma may be complex and yield a significant bation attempts will be predictably unsuccessful based incidence of CSI. on standard airway evaluation criteria, other options Certain injury patterns, such as facial injuries, are should be employed. MILS is preferable to traction associated with CSI. Among all facial injuries, there for minimizing cervical motion during intubation10; it was a 6.7% incidence of CSI in a retrospective study,7 is also an effective technique for minimizing cervical and the incidence appears to increase with greater spine motion while attempting intubation compared facial injury severity.8 Among patients with head inju- to the use of a soft or rigid collar.11 The best method to ries, there was a 7% rate of CSI.7 Patients with known immobilize an adult’s cervical spine is with the use of CSI are also at high risk for concomitant injuries. CSI a rigid cervical collar, sand bags, and restraining tape patients had a 13.5% incidence of facial injuries and a holding the patient’s head to a spine board.12 Unfortu- 40% incidence of head or brain injuries7; however, CSI nately, the use of maximal immobilization techniques should be considered in all trauma patients. Similarly, makes intubation more difficult. Full immobilization patients with known CSI should be considered high leads to a worsened grade of view of the vocal cords risk for coexisting head and facial injuries. with direct laryngoscopy. One study found a 64% The most common site of a cervical spine fracture incidence of a grade III or worse view, compared to a is C2 (24% of fractures), and the most common region 22% grade III or worse view with MILS.13 The use of a 122 Head and Neck Trauma rigid cervical collar also decreases mouth opening.14 but the insertion and inflation of an laryngeal mask The best-practice recommendation is to use MILS and airway was found to increase pressure in the cervical a rigid cervical collar with the front portion removed spinal canal in a cadaveric model.27 The significance of to allow for greater mouth opening. increased pressure in the spinal canal is unknown but No significant difference in cervical spine motion should be considered when weighing the benefits of a has been found when comparing the various blades laryngeal mask airway (ie, decreased neck motion and used for direct laryngoscopy in cadaveric models or an improved ability to ventilate or intubate a patient in live patients without cervical pathology.15,16 Several when conventional methods for either are inadequate) comparisons of video laryngoscopes to direct laryn- in a patient with a possible CSI. goscopy tools have shown some degree of superiority Tracheal intubation with a nasotracheal tube using of the video laryngoscopes. Use of the Bullard laryngo- a flexible fiberoptic bronchoscope reduces cervical scope (Circon ACMI, Stamford CT) decreases cervical spine motion relative to other forms of airway ma- spine motion and improves vocal-cord visualization nipulation,22 but inserting a tube through the nares is compared to direct laryngoscopy17,18 and, although concerning because it could pass out of the nasophar- the Bullard laryngoscope was associated with a longer ynx or potentially worsen a facial fracture in a patient time to successful intubation, the mean time was less with facial and head injuries. There is some evidence than 30 seconds.19 Similar results were found for the that this phenomenon is not clinically significant and Glidescope (Verathon Inc, Bothell, WA) when com- nasal intubation may be safe in patients with head and pared to direct laryngoscopy.20,21 facial trauma.28 Despite its safety, nasal intubation is Awake fiberoptic intubation for patients with a time consuming and can lead to epistaxis, which can possible or known CSI is common. In cadavers with make airway management far more challenging and induced cervical instability, tracheal intubation using a lead to an emergent direct laryngoscopy with resulting flexible fiberoptic bronchoscope caused the least cervi- cervical motion or an aspiration event. cal spinal canal distortion of all techniques used.22 The disadvantage of intubating a patient’s trachea using a Radiologic Assessment flexible fiberoptic bronchoscope prior to inducing an- esthesia is that it can be time- and resource-consuming If a patient is stable and there is not an obvious CSI, and it requires patient cooperation and operator ex- yet injury mechanism provides reason to suspect one, perience. There is no living human data supporting CSI should be evaluated. There are two major sets of the theory that an awake technique with a flexible criteria used to determine whether further radiologi- bronchoscope will lead to lower rates of secondary cal assessment is necessary or an injury can be ruled CSI, but it is standard practice when time and patient out without further studies. The National Emergency condition allow.23 X-Radiography Utilization Study (NEXUS) criteria In emergent intubations, awake intubation with a have been proposed as a way to determine the need for flexible fiberoptic bronchoscope may not be feasible. In radiologic studies to evaluate for a CSI. Patients who this situation, providers must determine if the patient meet NEXUS criteria for low risk of CSI should not can be successfully intubated, then MILS should be have further radiological studies.29 Low-risk criteria employed with an apneic technique for laryngoscopy are as follows: and intubation. When ventilation or intubation dif- ficulty is anticipated, awake fiberoptic bronchoscopy • No midline cervical tenderness or awake tracheostomy can be performed. In one • No focal neurological deficit study, tracheostomy in a cadaveric model of cervical • Normal alertness instability led to a small amount of canal distortion of • No intoxication unknown clinical significance.24 • No painful distracting injury (in which pain The impact of cricoid pressure on cervical spine from the injury distracts from pain associated motion has been evaluated.