Perfusion and Oxygenation in Polytrauma

Approximately 80% of patients with traumatic SCI (tSCI) have multiple injuries, some of which are overlooked in the presence of obvious SCI. Thus, polytrauma patients should undergo thorough evaluation with a keen awareness of associated injuries and respective timing of decompensation. Maintaining adequate oxygenation through a patent airway is a priority in polytrauma. Namely, high-flow oxygen should be administered with a mask to patients with cervical spine injury; in conscious patients with quadriplegia secondary to upper cervical spine injury and diaphragmatic breathing, early intubation and ventilation should be pursued to counteract poor respiratory effort and CO ₂ retention. Fiber-optic intubation with cervical spine control is the preferred method, as there is no evidence that orotracheal intubation with cervical traction will exacerbate SCI.

Once adequate oxygenation is maintained through airway management, circulation should be assessed. Traumatic SCI is often confounded by systemic hypotension and reduced spinal cord perfusion, which may worsen secondary neurologic injury. The current literature indicates that given the high percentage of multiple injuries concurrent with SCI, evaluation of all sources of occult internal hemorrhage is recommended. Commonly, concurrent injuries include damage to the chest wall contents associated with thoracic spine injury, retroperitoneal hemorrhage, pelvic fractures, and open long-bone fractures. Hypotensive shock (systolic blood pressure [SBP] < 90 mm Hg) should not be attributed to SCI or a neurogenic origin until the other sources of internal hemorrhage are ruled out. Once occult sources of hemorrhage have been fully excluded, fluid resuscitation is recommended for initial treatment of neurogenic shock and therapeutic targets include perfusion with SBP of 90 to 100 mm Hg, heart rate of 60 to 100 beats/min, urine output above 30 mL/h, and normothermia.

The management of a polytrauma patient with a pelvic fracture is a major diagnostic and therapeutic challenge. The pelvic space can hold up to 4 L of blood and in the setting of trauma can lead to pressure buildup and further hemorrhage with increased risk of mortality to upward of 50%. Implementation of resuscitation measures can reduce direct mortality risk related to pelvic trauma to 7%. In a hemodynamically unstable polytrauma patient with a pelvic fracture, the current literature points toward angiographic embolization as the mainstay of treatment. Karadimas and associates conducted a meta-analysis including 26 studies and found an overall embolization rate of 8.4% in pelvic fracture polytrauma. If this measure proves ineffective, evidence supports temporary pelvic packing via a laparotomy to quell bleeding, open reduction with internal fixation (ORIF), closed reduction with external fixation (CREF), or pneumatic antishock garments. It is important to note that angiography and embolization of pelvic fractures in polytrauma patients are not always optimal due to venous bleeding. Of the forms of mechanical stabilization, ORIF is most stable and can be used in conjunction with CREF as the leading choice for hemorrhage control.

In addition to mitigation of ongoing blood loss and sufficient volume or blood product resuscitation, aggressive blood pressure control should be a priority. The American Association of Neurological Surgeons (AANS) and Congress of Neurological Surgeons (CNS) state that blood pressure management guidelines in spinal cord injury should meet hemodynamic goals of a mean arterial pressure (MAP) of > 85 mm Hg while avoiding SBP less than 90 mm Hg for the first 5 to 7 days. These guidelines are derived from the concept that increased blood pressure leads to decreased damage to axonal function in sensorimotor pathways and requires the addition of vasopressor support. Several studies implementing aggressive hemodynamic goal-directed management suggest improved outcomes.

In summary, achieving hemodynamic stabilization in a polytrauma patient requires thorough evaluation of multisystem or occult injuries, with priority given to maintaining a patent airway, ensuring adequate ventilation and oxygenation, mitigating ongoing blood loss, ensuring adequate fluid and blood product resuscitation, and preserving spinal cord perfusion through targeted blood pressure goals.

Transport Considerations

Immobilization in the treatment of spine trauma includes early identification of injury and prevention of secondary injuries in the peri- and intraoperative settings. For suspected SCI, it is suggested that all trauma patients should be immobilized at the scene and during transport using a combination of a rigid cervical collar along with supportive blocks on a backboard with straps in the prehospital setting. In the event of extended transport time or delays in transferring to the destination facility, hardboards should be used with caution or substituted with padded boards to reduce the pressure on the occiput and sacrum. Although there is biomechanical evidence suggesting that the use of a cervical collar and board provide statistically significantly more immobilization that a collar by itself, there is no evidence to support the type of collar for best results. The long-standing practice of utilizing sandbags and tape alone is not recommended for cervical spine immobilization. Utilization of certain straps may further reduce lateral thoracolumbar spinal movement, but the clinical relevance of this reduction remains unknown. In addition, there is evidence to suggest the extended use of rigid boards can increase pressure and lead to tissue necrosis. Numerous studies demonstrate elevated tissue pressures even after short periods of rigid immobilization. With a paucity of data to define safe durations with hard board immobilizations and the impact of clinical outcomes based on the duration of hard board use, clinical guidelines for the method and duration of mobilization remain inconclusive.

Spinal Cord Injury Versus Vertebral Injury in Polytrauma

Polytrauma can lead to various types of neurologic damage, including spinal cord injuries (SCIs) and vertebral injuries. Nearly 12,000 new cases of nonfatal spinal cord injury are reported annually in the United States, and most of these SCIs have a concomitant injury to the vertebral column. Hence, the extent of injury after polytrauma is often not explicit, and differences between SCI and vertebral injury are debatable. Nevertheless, it is possible to shed some light on the considerations for cord versus vertebral injury with the understanding that the priority in the management of a polytrauma patient is to minimize secondary mechanical or physiologic insults to the spinal cord and vertebral column.

Although spinal cord injury occurs in only up to 5% of polytrauma cases, nearly 14% of these cases can become unstable and require rapid intervention. Minimizing cervical spine instability is a major consideration in polytrauma. Although there is limited evidence to support the use of spinal immobilization and airway management in all trauma victims, the importance of minimizing spinal and vertebral injury in a trauma victim cannot be overlooked. Current evidence indicates that immobilization of polytrauma patients should include a cervical collar, lateral supports and straps, as well as a spinal hardboard that should be padded to reduce pressure on the occiput and sacrum. In patients with known or suspected SCIs, the current Advanced Trauma Life Support (ATLS) guidelines indicate that manual in-line stabilization (MILS) with direct or indirect laryngoscopy should be the standard airway intervention technique in polytrauma patients with concomitant SCI and vertebral injury.

Regardless of whether SCI or vertebral injury is suspected in a patient who has suffered from polytrauma, thorough evaluation of the spine is warranted, especially in the unconscious or intoxicated patient. Specifically, evidence indicates aggressive evaluation in male patients < 45 years of age, Glasgow Coma Scale (GCS) < 15, and concomitant chest injury from falls > 3 m in height or motor vehicle accidents at speed > 70 kph.

The recommended imaging modality for suspected vertebral injury is computed tomography (CT), and for cord or vascular injury it is magnetic resonance imaging (MRI). CT has a higher specificity and sensitivity for cervical spine injury evaluation compared to plain films; specifically, CT is able to detect 97% to 100% of cervical spine fractures, whereas a single lateral view has a sensitivity of only 63%. Furthermore, CT is indicated as first-line imaging due to improved sensitivity and specificity in visualizing middle and posterior fractures. A detailed review of CT can provide explicit information about the integrity of both the spinal cord and the vertebral column. Stability should be maximized next to limit further neurologic damage or deformity. In the setting of polytrauma, the conscious patient with well-localized severe neck pain may have an unstable ligamentous injury without visible neurologic or radiographic abnormalities. This type of injury is most common in the cervical spine, and radiologic flexion/extension views of the cervical spine may best demonstrate occult instability. This is in contrast to suspected SCI in which MRI is the ideal imaging modality to assess for vascular injury, spinal cord hemorrhage, edema, and contusion. It is important to note that MRI scanning for a polytrauma patient is only suitable if the patient is hemodynamically stable—a challenge in the context of multisystem injury.

Overall, the considerations for differentiating and managing SCI versus vertebral injury secondary to polytrauma are not clearly explicit. Current guidelines indicate that necessary precautions should be made to secure airway management and minimize further damage regardless of whether SCI or vertebral injury has occurred. A conscious effort should always be made to ensure that airway, breathing, and circulation are assessed due to the risk of acute deterioration. Urgent intubation is crucial to airway management and assessment in the setting of polytrauma. Stabilization is often contingent on degree of cooperation from the patient, and the patient’s head/neck movement can often indicate the extent of injury during attempted intubation.

Indications for Surgery in Polytrauma

A clinically relevant classification system accounts for the natural history of injury, stratifies based on injury severity, and suggests a prognosis to guide clinical decision making. The Thoracolumbar Injury Classification (TLIC) and Severity Score of 2005 and the Subaxial Cervical Spine Injury Classification (SLIC) and Severity Score of 2007 have become validated as the most widely used scoring systems for thoracolumbar and cervical trauma, respectively. Both scoring systems incorporate the same three categories of injury characteristics with minor variations between the thoracolumbar and cervical spine, and they have since been externally confirmed for reliability and validity.

The three categories are as follows:

• 1.
  

  The injury morphology determined by pattern of disruption on imaging (component score 0 to 4)

  
  
• 2.
  

  The integrity of the posterior ligamentous complex (PLC) and discoligamentous complex (DLC) for thoracolumbar (TLIC) and cervical injury (SLIC), respectively (component score 0 to 3)

  
  
• 3.
  

  The neurologic status of the patient (component score 0 to 3)