Head and Spine Diagnosis and Decision-Making

Anatomy and Biomechanics

Head injuries have multiple mechanisms, which include the injuries from an impact of the brain against the inside of the skull ( Fig. 123.1 ). A coup injury occurs when the brain strikes the inner skull on the same side of impact of an object and typically occurs when a moving object comes into contact with a patient's stationary head. A countrecoup injury occurs when the brain strikes the inner side of a skull on the opposing side of impact of an object, which generally occurs when a mobile patient's head strikes a stationary object. The brain is suspended in cerebrospinal fluid (CSF), a fluid denser than the brain itself. In the cases of countrecoup injuries, the denser CSF moves towards the site of impact, likely displacing the brain in the opposite direction. The mechanisms behind coup and countrecoup injures are only relevant when there is no skull fracture present, because any such displacement to the skull would cause the bone to directly damage brain tissue upon an impact.

Damage to the brain from a head injury may result from three types of applied forces: compressive, tensile, and shearing. Compression force involves squeezing of brain tissue, and tensile force is the opposite of compression and involves stretching of brain tissue. When rotational forces are applied to the brain, shearing stress results from areas where rotational motion of the brain is hindered, such as at rough, irregular contacts between the brain and skull. In severe traumatic brain injuries, brain tissue experiences compression, tension, and shearing. Compressive and tensile forces are handled relatively well by the head because CSF is able to absorb and convert focal shock into a more widely distributed stress throughout the head. However, shearing stresses are less tolerated by the brain, with the most vulnerable parts being the brainstem and corpus callosum due to their highly anisotropically oriented axons.

Pathophysiology

Head injuries are found in a wide variety of sports. Concussion is the most commonly sustained head injury in athletes. However, it is poorly defined, and treatment modalities vary greatly and are dependent on a multitude of factors. Intracranial hemorrhage is the leading cause of death from head injury in athletes; four types exist—epidural, subdural, intracerebral, and subarachnoid. Intracranial hemorrhage is a focal brain injury that results from a ruptured blood vessel within the skull and leads to dangerous increases in intracranial pressure. Other severe, although less common, injuries include skull fractures, mild and severe traumatic brain injuries, CSF leaks, craniofacial injuries, and cranial nerve injuries.

As mentioned previously, concussions are the most common head injuries occurring in athletes. They have previously been defined as low-velocity injuries resulting in “brain shaking,” and clinical symptoms that may not necessarily be related to the initial pathologic injury ensue. The most recent (2012) Conference on Concussion in Sport differentiated concussion from a minor traumatic brain injury (mTBI) and considers the concussion to instead be its own subset of TBI. Concussions can be the result of low-velocity impact to the head, face, neck, or anywhere else in the body that can transmit “impulsive” force to the head. For adults, this is most commonly seen is vehicular collisions and falls, but for children, the most common causes are bicycle and sporting accidents. Concussions from vehicular collisions are likely to be much more severe and may include loss of consciousness (LOC) as compared with those concussions resulting from sporting accidents. Although concussions commonly occur in athletes, they are considered to be grossly underreported. There are a variety of reasons for which this can occur: a player might believe that reporting a concussion might curtail his player career; a team or organization might not want to report injuries so as not to harm its public relations. Nevertheless, it is important that players, teams, and families fully understand the ramifications of concussions, and it has been demonstrated that an increased knowledge of concussion symptoms is associated with an increase in concussion reporting.

At the time of injury, impairment of neurologic function can occur, although this is not necessary for diagnosis and impairment can appear hours after initial insult. Symptoms of a concussion typically resolve spontaneously. However, the course of recovery is variable, with some concussion patients experiencing symptoms weeks to months after acute injury. Concussions may or may not result in an LOC. In addition, if LOC does occur, it bears no effect on severity of concussion or recovery time. In some cases, concussions can result in the inability to remember new events (antegrade amnesia) or events immediately preceding the concussion (retrograde amnesia). Retrograde amnesia usually resolves spontaneously, although antegrade amnesia from concussions can be permanent. Because the acute clinical symptoms of a concussion reflect functional dysregulation instead of structural injury, concussion cannot be diagnosed with computed tomography (CT) or magnetic resonance imaging (MRI). However, imaging is used to rule out more serious injury, mainly hemorrhage.

History

Detailed history is imperative in patients sustaining head injury. Physicians should first determine whether further emergent neuroimaging is needed to rule out more severe brain injuries. Moreover, it is important to asses a patient's mental status and any changes since the initial injury. In many cases, it may be necessary to obtain a medical history from parents, friends, teammates, and coaches. In patients with concussions specifically, initial presentation may include a variety of symptoms and with differing severity. Physical symptoms can include headache, nausea, vomiting, issues with balance, photophobia, numbness and tingling, dizziness, and tinnitus. Cognitive symptoms may include depression, fatigue, irritability, sadness, nervousness, memory problems, and difficulty concentrating. Furthermore, it is important to note if patients have sustained previous head injury or concussions because a prior concussion is a significant risk factor for subsequent concussions. And although greater than 90% of sports-related concussions among children are not associated with an LOC, it is important to inquire about LOC to rule out other injuries. Symptoms after the first 4 weeks after injury are considered those the initial concussion, and those after 4 weeks are considered postconcussion syndrome (PCS), which can last anywhere from weeks to several months. It is therefore important to obtain pertinent history from both the initial injury and at follow-up to determine is any new or different symptoms are present and if they are part of normal recovery. A large majority (80% to 90%) of concussions resolve in 7 to 10 days; however, full recovery can vary, particularly in children and adolescents.

Physical Exam

An onsite licensed health care provider should initially ensure that the athlete is medically stable and has an open airway, adequate breathing, and circulation (ABCs). The health care provider must then determine the appropriate method of removing the player from the field and address any first aid issues such as active bleeding. After this, one should observe the injured player for immediate clinical symptoms and physical signs such as LOC, headache, dizziness, drowsiness, confusion, and seizure. Physicians, if possible, should also assess gait, balance, cranial nerve function, and coordination as part of a comprehensive neurologic examination. If the athlete displays an altered mental status or LOC, he or she should be immediately transferred to a hospital with neurosurgical services.

To assess a potentially concussive injury, one can use a sideline assessment tool such as the third edition of the Sport Concussion Assessment Tool (SCAT3). The SCAT3 is a standardized checklist for evaluating injured athletes for concussion, incorporating the Glasgow Coma Scale, Maddocks Score, scaled score of physical symptoms, cognitive assessment, neck examination, balance examination, and coordination examination. After initial assessment, the player should be monitored for increasing severity of initial symptoms or emergence of new symptoms. Those diagnosed with concussion should not be allowed to return to play (RTP) on the day of injury.

Imaging

As mentioned previously, concussions do not result in structural damage to the brain and therefore cannot be distinguished with CT or MRI. However, if there is a suspected intracranial hemorrhage from athletic injury, CT should be used. It is important for on-field medical staff and personnel to understand the general characteristics of the four basic types of hematomas: epidural, subdural, subarachnoid, and intracerebral.

Epidural hematomas are typically, but not always, characterized by a brief LOC. Individuals might present with a lucid interval where there is marked improvement before rapid decline in mental status. The athlete may regain consciousness before the subsequent deterioration and headache. This occurs due to blood from meningeal arteries building up between the dura mater and the skull. As a result a convex collection of blood is noted on imaging. Bleeding usually occurs on the same side of injury, and players who sustain epidural hematomas should be removed from the field and escorted to a hospital with neurosurgical services. There, the hematoma must be evacuated and a full recovery is expected if treated promptly.

A subdural hematoma is the most common fatal athletic head injury. Injured players experience LOC and do not usually regain consciousness. They should be sent immediately for neurosurgical evaluation. Blood escapes from torn bridging veins in the subdural space and builds between the dura mater and arachnoid mater, ultimately resulting in a concave collection of blood expanding past suture lines. Although a smaller subdural hematoma is self-limiting and requires only small catheter drill for evacuation, a craniotomy is needed to access a larger subdural hematoma. The risk of complications is dependent on the size and rate of change of the subdural hematoma, but the prognosis is poor because of direct damage to the brain.

A subarachnoid hemorrhage (SAH) consist of bleeding into the subarachnoid space, an area that houses CSF on the surface of the brain. A player who suffers an SAH from head trauma will likely present with rapid onset, severe headache (“worst headache ever”), pulsating towards the back of the head. Some patients will have neck stiffness, vomiting, seizures, and a decrease or LOC. Players should be taken to a hospital for a neurosurgical evaluation with CT scan. There they will receive treatment to reduce bleeding and prevent vasopasm. Surgery is likely not required if no vascular ruptures are present and the bleeding is contained superficially.

An intracerebral hemorrhage involves bleeding of the brain tissue itself. After the initial traumatic head injury, an athlete with cerebral bleeding will often present with severe headache and vomiting. This injury is commonly confused with SAH. Players should be referred to neurosurgical services. The mortality rate is between 35% and 52% and is even higher when the brainstem is affected; only 20% of survivors of survivors are expected to have a full recovery at 6 months.

Decision-Making Principles

As with all head injuries, players should be initially assessed for airway, breathing, and circulation and have their cervical spine stabilized. Athletes should be immediately removed from play if a concussion is suspected. The diagnosis of a concussion should be made using a multidisciplinary approach involving clinical symptoms, physical signs, cognitive impairment, neurobehavioral features, and sleep disturbance. It might be necessary to gather information from families, coaches, and teammates if a player is unable to provide enough details of the injury. Furthermore, clinical assessment tools such as Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and SCAT3 can be used but should not supplant a clinician's judgment in assessing an athlete for a concussion. Because concussions are the result of functional but not structural damage to the brain, neuroimaging contributes little to the diagnosis and should only be used to rule out intracranial bleeding. Thus clinicians should avoid ordering a brain CT or brain MRI unless there is concern for a skull fracture, progressive neurologic symptoms, or focal neurologic findings.

Treatment Options

The only proven treatments for concussions are cognitive and physical rest. Cognitive rest entails avoiding concentration-driven activities such as school work, video games, and even leisurely reading. Players diagnosed with concussions should not RTP on the same day of injury; however, there is no broad consensus on the appropriate guidelines for returning players. It is widely agreed that players should not RTP until they are asymptomatic, and during this recovery period, players should not take analgesic or sedative medications to mask postconcussion symptoms. The latest (2016) Zurich International Consensus Statement on Concussion in Sport and the American Medical Society for Sports Medicine both endorse a stepwise progression in physically demanding activity for players who previously suffered from concussion and are subsequently asymptomatic off medicine. The steps of the Zurich Statement progress in the following order: symptom-limited activity, light aerobic exercise, sport-specific exercise, noncontact training drills, full-contact practice, and finally RTP. Each of these steps must be separated by at least 24 hours of asymptomatic activity before the athlete may progress to the next step after a brief initial period of rest (24–48 hours). Finally, it is generally recommended that children suffering from concussions be treated more conservatively than adults. Athletes with concussions should be monitored for symptoms while in the rest and recovery period. Individuals who suffer concussions are at increased risk of suffering subsequent concussions.

Authors’ Preferred Technique

Players with suspected concussions should be immediately removed from play and assessed by a licensed health care professional for clinical symptoms and physical signs of the injury. If the player shows signs characteristic of intracranial bleeding, he or she should be quickly sent to a hospital with neurologic services and there undergo appropriate neuroimaging and surgery, if necessary. Individuals suffering only a concussion should be given time for physical and cognitive rest until symptoms resolve before returning to light aerobic physical activity. They can then graduate in a stepwise fashion to full-contact play if they remain asymptomatic while off medications.

Results

As mentioned previously, the overwhelming majority (80% to 90%) of concussions will resolve spontaneously in 7 to 10 days. Those with symptoms persisting past 10 days should be evaluated for coexisting pathologies through conventional neuroimaging and neuropsychological testing. Although there is no effective drug treatment for concussion itself, symptoms of concussions and PCS that persist can be treated with antidepressants and analgesics, as well as cognitive, vestibular, physical, and psychological therapy.

Complications