Neurosurg Focus 33 (6):E6, 2012 Structural brain injury in sports-related concussion SCOTT L. ZUCKERMAN, M.D.,1 ANDREW KUHN,2 MICHAEL C. DEWAN, M.D.,1 PETER J. MORONE, M.D.,1 JONATHAN A. FORBES, M.D.,1 GARY S. SOLOMON, PH.D.,1 AND AllEN K. SIlls, M.D.1 1Department of Neurological Surgery, Vanderbilt Sports Concussion Center, Vanderbilt University School of Medicine, Nashville, Tennessee; and 2College of Arts and Sciences, Boston University, Boston, Massachusetts Object. Sports-related concussions (SRCs) represent a significant and growing public health concern. The vast majority of SRCs produce mild symptoms that resolve within 1–2 weeks and are not associated with imaging-docu- mented changes. On occasion, however, structural brain injury occurs, and neurosurgical management and intervention is appropriate. Methods. A literature review was performed to address the epidemiology of SRC with a targeted focus on structural brain injury in the last half decade. MEDLINE and PubMed databases were searched to identify all studies pertaining to structural head injury in sports-related head injuries. Results. The literature review yielded a variety of case reports, several small series, and no prospective cohort studies. Conclusions. The authors conclude that reliable incidence and prevalence data related to structural brain injuries in SRC cannot be offered at present. A prospective registry collecting incidence, management, and follow-up data after structural brain injuries in the setting of SRC would be of great benefit to the neurosurgical community. (http://thejns.org/doi/abs/10.3171/2012.10.FOCUS12279) KEY WORDS • concussion • sports • subarachnoid hemorrhage • epidural hemorrhage • subdural hemorrhage • malignant cerebral edema • second-impact syndrome ONCUSSION, also termed mild TBI, is broadly de- study identified girls’ soccer, girls’ basketball, and boys’ fined as a transient, trauma-induced physiological wrestling as the second, third, and fourth most implicated disruption of brain function.44,79 According to the sports, respectively, in concussion incidence.54 Female Cinternational body of experts making up the Concussion athletes seem to be at greater risk for concussion than in Sport Group, concussion results in the rapid onset of their sport-matched male counterparts.48,54 Similarly, short-lived impairment of neurological function that re- younger athletes appear to not only be more susceptible solves spontaneously with no abnormality seen on stan- to concussion, but also take longer to recover.38,105 dard structural neuroimaging studies.59 Sports-related While most concussions produce symptoms that re- concussions comprise nearly 9% of all injuries sustained solve spontaneously, more severe injuries, reflected by during athletics, and emergency department visits for positive imaging studies, are seen in a small subset of SRCs among children and adolescents have increased by athletes with SRC. The spectrum of sports-related con- 60% in the last decade.32,36 About one-third of SRCs are cussion with structural brain injury (SRCSBI) includes sustained by high school football players alone.36 While the following: 1) SAH; 2) EDH; 3) SDH; and 4) malig- collision and contact sports like football, ice hockey, nant cerebral edema, dubbed second-impact syndrome, soccer, and lacrosse garner much attention, concussion or SIS.10,14,15,57,58,64,101 All cases are medical emergencies. rates in other sports are significant. A recent nationwide Due to their infrequency, epidemiological and long- term data are lacking for the more severe SRCSBI cases. The objective of our article is to review the literature on Abbreviations used in this paper: AC = arachnoid cyst; ASDH sports-related structural head injuries and to offer per- = acute subdural hemorrhage; CSDH = chronic SDH; EDH = epidural hemorrhage; GCS = Glasgow Coma Scale; LOC = loss of spective on how to learn more about these rare injuries consciousness; MLS = midline shift; SAH = subarachnoid hemor- and improve treatment, outcomes, and prevention. We rhage; SCI = spinal cord injury; SIS = second-impact syndrome; also include comments about our own institutional expe- SRC = sports-related concussion; SRCSBI = SRC with structural rience with SRCSBI, which has not been previously pub- brain injury; TBI = traumatic brain injury; tSAH = traumatic SAH. lished. Neurosurg Focus / Volume 33 / December 2012 1 Unauthenticated | Downloaded 09/26/21 10:18 AM UTC S. L. Zuckerman et al. Methods hemorrhage in SRCSBI may be divided into categories based on the site or origin and pattern of bleeding. Isolat- MEDLINE and PubMed records were searched to ed tSAH is an uncommon sport-related head injury; the identify all studies pertaining to structural injuries in literature is limited to small series and case reports (Table the setting of SRC in the last half-decade. The proceed- 2).33,77 This form of SAH is a consequence of momentary ing terms were used as Medical Subject Heading terms oscillation of the brain as a result of rotational accelera- and text words: sport-related head injury, concussion, tion of the head and subsequent shearing of small cortical catastrophic head injury, diffuse axonal injury, epidural vessels.28 Often diagnosed on CT scans as a hyperdense hemorrhage, subarachnoid hemorrhage, subdural hem- focus along the convexity, this type of brain injury has orrhage, malignant cerebral edema, and second impact been described as an isolated finding in mild TBI or as a syndrome. The reference lists of these articles were ex- component of additional injuries that includes traumatic amined to identify additional relevant research. Of note, axonal injury, SDH, or other structural injuries.29,80 we defined “sport-related” as any endeavor in which an Other forms of SAH in athletes may be due to trau- individual was performing an athletic activity alone or in ma-induced large-vessel damage or aneurysm rupture competition against an opposing person or team. Tradi- precipitated by a traumatic event. Blows to the neck or tional team sports were included, such as basketball, foot- base of the skull caused by a puck (hockey),80 collision ball, and soccer, in addition to individual sports such as with a tackler (rugby),61 and an opponent’s foot (martial snowboarding or equestrian events. arts, kickboxing)21,53 have all been described as causing vertebral artery injury and subsequent hemorrhage. Sub- Results arachnoid hemorrhage caused by aneurysm rupture in the setting of athletic play has also been described in soc- We found a total of 40 articles containing reports of cer,11 hockey,81 and weightlifting,39 sometimes blurring SRCSBI. The study types included 28 case reports, 10 the distinction between tSAH and traditional aneurysmal case series, 1 observational cohort design, and 1 case- SAH. In these scenarios, an underlying vascular lesion control study. We provide a summary of all sports impli- is subjected to extreme external or hemodynamic forces, cated in reported cases of SRCSBI (Table 1). We present precipitating catastrophic hemorrhage. these data based on the type of structural damage seen. As in non–sport-related trauma, the finding of a cul- When overlap between intracranial injuries existed in a prit aneurysm portends a worse prognosis, whereas tSAH single publication, the paper was categorized based on the from cortical vessel rupture alone often involves a benign most relevant lesion discussed. recovery. In patients with mild TBI, Deepika and asso- ciates26 demonstrated no difference in outcome between Subarachnoid Hemorrhage patients with isolated SAH and those with a normal CT Subarachnoid hemorrhage is defined as bleeding into scan. In patients with severe TBI, however, there is de- the subarachnoid space, between the arachnoid mem- bate about the risk of tSAH-related cerebral vasospasm and whether antivasospastic therapy should be employed. brane and pia mater surrounding the brain. Subarachnoid In a retrospective review of 117 patients with tSAH, Lin et al.47 found extensive tSAH to be an independent risk TABLE 1: Sports implicated in cases of sport-related structural factor for vasospasm, as were age and initial GCS score. brain injuries Conversely, a study by Shahlaie and coauthors88 found only parenchymal contusions and fever—not the presence Sport of SAH—to be associated with posttraumatic vasospasm. basketball In our clinical practice, SAH is rarely seen after boxing sport-induced mild TBI. In patients with convexity tSAH associated with mild TBI—sports related or otherwise— cycling and reassuring examination findings, antiplatelet or anti- equestrian coagulation medication is withheld for 1 week, at which football point a repeat CT scan is obtained to confirm the evolu- golf tion and nonexpansion of subarachnoid blood. Further- ice hockey more, episodes of tSAH may occur undetected after SRC jump training even in cases of transient concussive symptoms. A high index of suspicion is essential in these situations. kickboxing Overall, the literature on sport-related SAH is limit- martial arts ed to case report and case series data only. Several reports race walking have cited aneurysm rupture incited by sport-related trau- rugby ma, whereas others have noted tSAH with no associated 11,83,40 skateboarding aneurysmal involvement. The general neurosurgery snow skiing literature is helpful in extrapolating trends and outcomes, but sport-specific data are lacking. snowboarding soccer Epidural Hemorrhage weightlifting An EDH occurs when there is bleeding between the 2 Neurosurg