Management of Pediatric Severe Traumatic Brain Injury

Acknowledgment

Medical illustrations were drafted and refined by Dr. Shih Liu, USF Department of Neurosurgery.

Introduction

Worldwide, more than 50 million suffer traumatic brain injury (TBI) each year, and it is estimated that about half the world’s population will have one or more TBIs over their lifetime. Today, TBI still remains a leading cause of injury-related morbidity and mortality among the pediatric population. The impact on the individual child as well as the injured child’s family provides a potent stimulus for improving management techniques within the neurosurgical community. While the exact financial cost of pediatric TBI to the family, society, and the medical system is not known, it has been estimated to be in excess of $50 billion annually in direct costs with additional indirect costs to the families of these children including lost wages and other nonmedical expenditures in the United States alone. It is known, however, that chronically disabled children require approximately four times the medical expenditures compared to their nondisabled cohorts throughout their lifetimes. This burden, along with the relative lack of defined standards of clinical care for pediatric TBI, drives the search for improved methods for prevention and intervention in this patient group.

Approximately 600,000 children in the United States visit the emergency department each year due to a TBI. This results in nearly 60,000 hospitalizations and over 7400 deaths annually. Children less than 4 years old tend to visit the emergency department (ED) most frequently while adolescents are more commonly hospitalized and have the highest death rate of 24.3 per 100,000 secondary to TBI. ^, In those areas where it has been instituted, regionalization of pediatric trauma centers has taken a large step in reducing the morbidity and mortality of TBI among this population. It has been demonstrated that injured children with moderate or severe TBI are more likely to undergo acute neurosurgical intervention and have improved outcomes when treated at a pediatric trauma center as opposed to adult trauma centers. With the likely future shortages of pediatric sub-specialists available at all Level 1 or 2 trauma centers to provide care, future steps to maintain and ultimately improve these outcomes may require regionalization to ensure volume and expertise.

This chapter will briefly review the past and present state of neurosurgical management of pediatric TBI. Core topics will include diagnostic and management technologies, surgical and critical care guidelines and strategies, as well as adjuncts for optimization of care. The balance of the chapter will focus on the newest innovations in diagnosis, management, and surgical intervention as a means to stimulate forethought and creativity among the neurosurgical community toward optimizing outcomes among children who have incurred TBI.

Emergency Evaluation and Triage

With such a high annual volume of children visiting EDs suffering from TBI, it is critical that the emergency provider be comfortable with the triage and workup of these often critically injured patients. Numerous studies have been undertaken to help define guidelines for workup of children with suspected TBI, including the Children’s Head Injury Algorithm for the Prediction of Important Clinical Events, through the Pediatric Emergency Care Applied Research Network (PECARN), the National Emergency X-Radiography Utilization Study (NEXUS), and the Canadian Assessment of Tomography for Childhood Head Injury. However, despite the worldwide efforts to develop guidelines and algorithms when presenting to an ED, each institution’s management remains highly variable without any one standard.

Diagnostic imaging protocols and technology in the setting of acute pediatric TBI has received much attention in recent years. A general trend toward minimizing some imaging modalities, in particular the use of computed tomography (CT), has been due to concerns of potential delayed radiation injury and impact on long-term neoplastic conversion. In turn, the use of other modalities, as well as improvements in technology, has led to diagnostic changes. Refinement of CT protocols have lessened the radiation exposure of these children yet still provide the requisite early, accurate, clinically significant information for medical decision-making.

Practice patterns have been tracked in several retrospective studies. Rhine et al. examined factors that influenced a clinician’s decision to obtain neuroimaging, observe, or discharge a child after assessment of children aged 0 to 4 years who were felt to be at risk for clinically significant TBI. In their group of 104 children, 30 underwent neuroimaging, 59 were observed, and 15 were discharged following initial exam. Those children who per caregiver reports were not acting normally were more likely to be initially observed. Those with non-frontal scalp hematomas were more likely to obtain immediate neuroimaging. Altered mental status, unclear skull fracture on exam, and age less than 3 months also were associated with higher likelihood of providers obtaining neuroimaging.

The American College of Radiology Appropriateness Criteria (AC) for pediatric head trauma are guidelines that were developed to assist physicians in making appropriate imaging and treatment choices in children with neurotrauma. Overall, the recommendations are based on the child’s Glasgow Coma Scale (GCS) score and age, as well as presence of high-risk factors including altered mental status or clinical evidence of a basilar skull fracture. These guidelines can help the emergency provider best determine the appropriate imaging modality for the child. Rao et al. assessed the appropriateness of neuroimaging in pediatric neurotrauma patients via these recommendations. They found that with these guidelines, 90.3% of patients were appropriately imaged with either CT or MRI. Understandably, younger patients were more likely to be inappropriately imaged than older patients. These studies though did not address the utility of several different imaging modalities for the pediatric TBI patient. Level of evidence for current emergency evaluation and imaging guidelines can be found in Table 76.1 .

Table 76.1

Level of Evidence for Emergency Evaluation and Imaging in Pediatric Traumatic Brain Injury

Level of Evidence	Topic	Recommendation	Supporting Publications
II II III	Cranial imaging	High-risk factors identify children at risk for neurologic intervention and brain injury as determined by CT head Low-risk factors identify children at low risk of clinically important TBIs for whom CT head may be unnecessary For cranial trauma in children, fractures of the petrous temporal bone or through carotid canal, focal neurologic deficit, and GCS <8 are independent risk factors for blunt cerebrovascular injury	Osmond et al., 2010 Kupperman et al., 2009 Ravindra et al., 2015
II	Cervical spine imaging	If NEXUS criteria negative, further c-spine imaging likely unnecessary	Hoffman et al., 2000

CT , Computed tomography; GCS , Glasgow coma scale; TBI , traumatic brain injury.

Plain Radiographs

Plain skull films are rarely used today in pediatric trauma centers. Presently, the skull radiograph is used primarily as a map for identification of foreign bodies or to document child abuse as part of a skeletal survey.

Computed Tomography

For TBI, the non-contrast axial head CT is the imaging modality of choice in pediatric neurotrauma. The scan can be performed very rapidly and provide immediate information regarding cranial injury, intra- and extra-axial blood, fractures, ventriculomegaly associated with TBI, and to a less-specific degree, ischemia. The progression of intra- and extra-axial hemorrhagic lesions has been well documented and a repeat CT scan may be obtained within 12 hours if significant blood is present or there is a change in neurologic status. In adults, Oertel and colleagues evaluated 142 cases and described hemorrhagic progression by hematoma type as follows: 51% in parenchymal contusions, 22% in epidural hematomas, and 11% of subdural hematomas on 24-hour, follow-up CT scanning. Unique to the pediatric population is the usual absence of anticoagulant use for comorbid conditions; this likely decreases the development of a delayed insult on CT from 85% to 31%. These results can be applied to the pediatric TBI patient as a general guide in assessing the need for repeat CT evaluation but potentially used judiciously when indicated to determine need for surgical intervention or escalation of therapy.

Concern has been raised about the effect that ionizing radiation has on the immature central nervous system. The estimated rate of lethal malignancies from CT is 1 per 1000 to 1 per 5000 scans with increased risk with younger age. ^, With improved technology, effective imaging with high-quality diagnostic scans can be obtained at lower radiation levels. Ultimately, it is about having images sufficient to make a medical or surgical decision and these can be achieved with modifications in the imaging algorithms to lessen radiation doses significantly. Prediction models for the use of CT in mild TBI (GCS 14 to 15) for the pediatric population have suggested that it is likely best to avoid the unnecessary scan. Many times the decision for re-imaging is subjective and based on center and/or individual physician’s practice, bias, and scope rather than actual indication. It is worthwhile to note the utility of CT scan in select cases. In one study of 14,969 pediatric patients who underwent CT scanning of the head for suspected TBI and met study parameters, 376 (0.9%) had clinically important TBI (defined as requiring acute intervention including neurosurgery), and only 60 (0.1%) underwent neurosurgery. The negative predictive value is 100% if the following criteria were met: (1) normal mental status, (2) no scalp hematoma except frontal, (3) no loss of consciousness or loss of consciousness for less than 5 seconds, (4) non-severe injury mechanism, (5) no palpable skull fracture, and (6) acting normally per parents. The negative predictive value is equivalent in children over 2 years of age with normal mental status, no loss of consciousness, no vomiting, no severe headache, no evidence of basilar skull fracture, and non-severe injury mechanism. It can be concluded from these data that if all of the criteria above are met, CT scanning in the low-risk TBI pediatric population may be avoided. Even in the higher-risk categories, the authors’ preference is not to repeat imaging unless there is consideration for a change in management strategy, that is, decision-making for surgical intervention. The 2019 updated Brain Trauma Foundation guidelines highlight the known standards of care based on the literature for treatment of pediatric severe TBI. The level III evidence recommendation is that excluding the possibility of elevated intracranial pressure (ICP) on the basis of a normal initial CT head is not suggested in comatose pediatric patients. As well, routinely obtaining a repeat CT scan greater than 24 hours after admission and the initial follow-up is not suggested for decisions about neurosurgical intervention unless there is evidence of neurologic deterioration or increasing ICP.

Recently there has been an increased utilization of the so-called pan scan including head, cervical spine, chest, abdomen, and pelvis. Tillou and colleagues reported on the effectiveness of the pan CT scan in an adult cohort indicating that if any study was omitted, from 311 CT scans, 17 injuries (5.4%) requiring immediate attention would have been missed. We recommend that if a child meets criteria, it is reasonable to consider carefully each patient’s mechanism of injury, neurologic status, and age prior to undertaking a “pan scan” to limit the potential radiation exposure. While a large part of this decision-making is determined by the trauma surgery service, a collaborative consensus for imaging protocols should optimize those patients receiving CT. With the advent of “pediatric” protocols developed to lower the radiation load without compromising image quality, these studies, especially if limited to the head and cervical spine, can facilitate the care of the patient, reducing time in the radiology department and providing a wealth of information useful for clinical decision-making.

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) in the pediatric trauma population is problematic primarily due to time constraints. The time for examination is significantly longer than CT and frequently requires sedation in the young to ensure adequate image quality. If the patient is intubated in the field or on arrival to the ED, MRI becomes a more practical modality with extension of sedation, although the decision should be based on a specific question particularly as it relates to the cervical spine. In emergent and urgent settings, the potential benefits of subtler imaging seldom outweigh the screening achieved by CT alone for cranial trauma. This may differ in the cervical spine where bony abnormalities are less commonly found in children and soft tissue injury may be better imaged by MRI.

Following the emergent acute phase, it must be recognized that certain manufacturer implants such as ICP sensors, EEG leads, or cranial bolts have to be removed or disconnected to ensure safety from potential further injury or artifact such as inducible radio frequency heating, movement in the magnetic field leading to further parenchymal damage, or metallic artifact from skin staples. Thus, at this time, MRI in the acute setting has little efficacy and practical utility for TBI. However, in the subacute trauma period, MRI can be very useful in helping prognosticate patient outcome and in guiding further clinical decision-making.

Adjuvant Imaging

Ultrasound

As discussed, CT remains the standard for emergent diagnosis of both skull fractures and TBI. Prompt identification of fractures in the ED is critical, as they are often associated with nonaccidental trauma and place the child at increased risk for TBI. Several centers have recently utilized point-of-care ultrasound (POCUS) in the evaluation of pediatric skull fractures. In a multicenter prospective study, Parri et al. attempted to determine the accuracy of POCUS in identifying skull fractures in children less than age 2. Their work demonstrated that POCUS has a 90.9% sensitivity and an 85.2% specificity for identifying skull fractures. This suggests that this tool can be readily utilized by emergency providers with high index of suspicion for skull fracture as a screening tool prior to subjecting the young child to radiation from CT.

Computed Tomography Angiography

CT angiography (CTA) is frequently used in the adult TBI population to evaluate for any traumatic cerebrovascular injury but it has been used with hesitancy in the pediatric population given the increased levels and risk of radiation required for adequate diagnostic imaging. Ravindra et al. evaluated 234 children who did happen to undergo CTA screening for TBI and their final results demonstrated that in children with GCS less than 8, fracture of the petrous temporal bone or through the carotid canal, stroke, or focal neurologic deficit were independent risk factors for blunt cerebrovascular injury. Therefore, CTA may be warranted in children presenting with any of those risk factors.

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