Adam J. Bartsch

Heading in soccer: dangerous play?

Soccer is the worlds most popular sport and unique in that players use their unprotected heads to intentionally deflect, stop, or redirect the ball for both offensive and defensive strategies. Headed balls travel at high velocity pre- and postimpact. Players, coaches, parents, and physicians are justifiably concerned with soccer heading injury risk. Furthermore, risk of long-term neurocognitive and motor deficits caused by repetitively heading a soccer ball remains unknown. We review the theoretical concerns, the results of biomechanical laboratory experiments, and the available clinical data regarding the effects of chronic, subconcussive head injury during heading in soccer.

Subconcussive Impact in Sports: A New Era of Awareness

ional athletes vanced degenaradigm shift tion experts. only an all-orso result from al detrimental nto the media veteran footer of the ball were heavier, after a 5-year tensive degenCTE were disted as cause of y” was docuA concussive episode refers to inertially induced duced traumatic alteration of function of the cere associated imaging abnormalities. Appreciation f of gravity linear acceleration, angular velocity, and eration during dynamic motion of the head a emerged recently in the neurosurgical community literature details potential detrimental effects of r cussive episodes in contact sports such as boxin American football (4, 8, 13-15, 25, 32, 35-37), rug 42), hockey (9, 49, 50), and soccer (18, 23, 24, repeat concussive episode before resolution of init symptoms has been associated with fatal cerebral hypothesized “second impact syndrome” (5, 6, 27 prevention efforts in sports have focused on minim lete’s concussive episode risk, and although the e tive subconcussive trauma in contact sports ha creased attention recently, it has yet to be fully add The term dementia pugilistica (22) describes a syndro sive neurodegeneration, first described in retired box repetitive subconcussive head impacts, that shares logic features with Alzheimer disease (1, 2, 11, 31, 3 term replacing dementia pugilistica, chronic traumati pact-inwithout ad center lar accelrain has luminous itive con, 17, 26), 9, 20, 29, 46-48). A ncussion a via the ain injury g an athof repetieived ined. f progresxposed to icopatho. The new phalopathy which is recognized to result from a variety of minor CTE is associated with personality changes, memor parkinsonism, and speech and gait abnormalities. P marks include gross cerebral andmedial temporal lo extensive tau-immunoreactive neurofibrillary tangle 30, 45). Spurred by highly publicized cases of profess who died at a young age and were found to have ad erative brain changes at autopsy, there has been a p among sports medicine and head injury preven An increasing realization is that brain injury is not nothing phenomenon (eg, concussion) but may al accumulated subconcussive impacts. The potenti effect of repetitive heading in soccer was thrust i limelight in 2002 following the death of English baller Jeffrey Astle. Astle had been a prolific head during an era in which the leather balls employed especially in wet conditions. Astle died at age 59 history of rapidly deterioratingmental capacity. Ex erative brain disease and taupathy consistent with covered at autopsy;minor repetitive traumawas sta death, and a verdict of “death by industrial injur ic entity, mented (28). This ruling of cause of death was especially striking

Boxing and mixed martial arts: preliminary traumatic neuromechanical injury risk analyses from laboratory impact dosage data

OBJECT In spite of ample literature pointing to rotational and combined impact dosage being key contributors to head and neck injury, boxing and mixed martial arts (MMA) padding is still designed to primarily reduce cranium linear acceleration. The objects of this study were to quantify preliminary linear and rotational head impact dosage for selected boxing and MMA padding in response to hook punches; compute theoretical skull, brain, and neck injury risk metrics; and statistically compare the protective effect of various glove and head padding conditions. METHODS An instrumented Hybrid III 50th percentile anthropomorphic test device (ATD) was struck in 54 pendulum impacts replicating hook punches at low (27-29 J) and high (54-58 J) energy. Five padding combinations were examined: unpadded (control), MMA glove-unpadded head, boxing glove-unpadded head, unpadded pendulum-boxing headgear, and boxing glove-boxing headgear. A total of 17 injury risk parameters were measured or calculated. RESULTS All padding conditions reduced linear impact dosage. Other parameters significantly decreased, significantly increased, or were unaffected depending on padding condition. Of real-world conditions (MMA glove-bare head, boxing glove-bare head, and boxing glove-headgear), the boxing glove-headgear condition showed the most meaningful reduction in most of the parameters. In equivalent impacts, the MMA glove-bare head condition induced higher rotational dosage than the boxing glove-bare head condition. Finite element analysis indicated a risk of brain strain injury in spite of significant reduction of linear impact dosage. CONCLUSIONS In the replicated hook punch impacts, all padding conditions reduced linear but not rotational impact dosage. Head and neck dosage theoretically accumulates fastest in MMA and boxing bouts without use of protective headgear. The boxing glove-headgear condition provided the best overall reduction in impact dosage. More work is needed to develop improved protective padding to minimize linear and rotational impact dosage and develop next-generation standards for head and neck injury risk.

Hybrid III anthropomorphic test device (ATD) response to head impacts and potential implications for athletic headgear testing

The Hybrid III 50th percentile male anthropomorphic test device (ATD) is the most widely used human impact testing surrogate and has historically been used in automotive or military testing. More recently, this ATD is finding use in applications evaluating athletic helmet protectivity, quantifying head impact dosage and estimating injury risk. But ATD head-neck response has not been quantified in omnidirectional athletic-type head impacts absent axial preload. It is probable that headgear injury reduction that can be quantified in a laboratory, including in American football, boxing, hockey, lacrosse and soccer, is related to a number of interrelated kinetic and kinematic factors, such as head center of gravity linear acceleration, head angular acceleration, head angular velocity, occipito-cervical mechanics and neck stiffness. Therefore, we characterized ATD head-neck dynamic response to direct head impacts in a series of front, oblique front and lateral head impacts. Key findings were: (1) impacts producing highest ATD resultant center of gravity linear acceleration resulted in the lowest resultant occipito-cervical spine bending moment/force. (2) Resultant ATD head angular velocity and angular acceleration did not appear coupled to impact direction at lower impact energy levels; these parameters were coupled at higher energy levels. (3) The ATD had progressively increasing occipito-cervical stiffness in extension, torsion and lateral bending, respectively. Because the ATD neck influenced head and neck impact dosage parameters, testing agencies, manufacturers and researchers should consider using the Hybrid III head form attached to a neck as a means to quantify head and neck injury risks as opposed to systems that do not utilize a neck. This heightened understanding of Hybrid III ATD head-neck response, and consideration of order of stiffest axes in the lateral, oblique and extension directions, respectively, should aid in the development of head and neck injury impact testing standards.

Analysis of baseball-to-helmet impacts in major league baseball

Background: In Major League Baseball (MLB), helmet hit-by-pitch (H-HBP) incidents are a leading cause of concussion. However, not all H-HBPs result in diagnosed concussion. Purpose: This study was designed to (1) quantify batter concussion risk as a function of H-HBP pitch velocity, time duration batter spent on the ground post–H-HBP, first responder assessment time duration, and number of days missed post–H-HBP and (2) estimate H-HBP impact locations on the helmet with respect to current National Operating Committee on Standards for Athletic Equipment (NOCSAE) helmet test standards and correlate impact locations with concussion diagnosis. Study Design: Case-control study; Level of evidence, 3. Methods: A retrospective case-control study of 18 MLB players with H-HBP incidents in the 2009 and 2010 seasons was undertaken. A database was compiled via quantitative and qualitative analysis using video coverage obtained from MLB. Quantitative factors included batter concussion diagnosis, pitch velocity, number of days missed post–H-HBP, time duration batter spent on the ground post–H-HBP, and first responder assessment time duration. The H-HBP impact location was among several qualitative factors developed via video analysis of each H-HBP from 4 raters. Results: In our study, 9 players (50%) were diagnosed with concussion. Concussion diagnoses were more frequent for posterior versus anterior impacts. The majority of H-HBP impact locations were different from those in the current NOCSAE standard tests. First responders took an average of approximately 65 seconds (time to reach batter plus assessment time) to decide on batter removal/return to play. The 25% logistic regression concussion risk threshold for pitch velocity and days missed was 86.2 mph and 1.3 days, respectively. The number of days missed after H-HBP showed a significant correlation (P = .02) among concussed and nonconcussed batters. Conclusion: In professional baseball H-HBP incidents, first responders should (1) be aware of pitch velocity in excess of 86 mph and (2) be provided ample time when assessing batters’ removal/return to play. Clinical Relevance: First responders should not rely solely on visual indicators such as batter reaction, holding head, or amount of time spent on the ground after H-HBP when assessing batters for concussion. Batting helmets in the MLB should maximize protection and mitigate impact dosage for H-HBP impact locations and velocity in addition to NOCSAE standard test locations and velocities.

Biomechanical analysis of the upper thoracic spine after decompressive procedures

BACKGROUND CONTEXT Decompressive procedures such as laminectomy, facetectomy, and costotransversectomy are routinely performed for various pathologies in the thoracic spine. The thoracic spine is unique, in part, because of the sternocostovertebral articulations that provide additional strength to the region relative to the cervical and lumbar spines. During decompressive surgeries, stability is compromised at a presently unknown point. PURPOSE To evaluate thoracic spinal stability after common surgical decompressive procedures in thoracic spines with intact sternocostovertebral articulations. STUDY DESIGN Biomechanical cadaveric study. METHODS Fresh-frozen human cadaveric spine specimens with intact rib cages, C7-L1 (n=9), were used. An industrial robot tested all spines in axial rotation (AR), lateral bending (LB), and flexion-extension (FE) by applying pure moments (±5 Nm). The specimens were first tested in their intact state and then tested after each of the following sequential surgical decompressive procedures at T4-T5 consisting of laminectomy; unilateral facetectomy; unilateral costotransversectomy, and subsequently instrumented fusion from T3-T7. RESULTS We found that in all three planes of motion, the sequential decompressive procedures caused no statistically significant change in motion between T3-T7 or T1-T12 when compared with intact. In comparing between intact and instrumented specimens, our study found that instrumentation reduced global range of motion (ROM) between T1-T12 by 16.3% (p=.001), 12% (p=.002), and 18.4% (p=.0004) for AR, FE, and LB, respectively. Age showed a negative correlation with motion in FE (r = -0.78, p=.01) and AR (r=-0.7, p=.04). CONCLUSIONS Thoracic spine stability was not significantly affected by sequential decompressive procedures in thoracic segments at the level of the true ribs in all three planes of motion in intact thoracic specimens. Age appeared to negatively correlate with ROM of the specimen. Our study suggests that thoracic spinal stability is maintained immediately after unilateral decompression at the level of the true ribs. These preliminary observations, however, do not depict the long-term sequelae of such procedures and warrant further investigation.

Cleveland Clinic intelligent mouthguard: a new technology to accurately measure head impact in athletes and soldiers

Nearly 2 million Traumatic Brain Injuries (TBI) occur in the U.S. each year, with societal costs approaching

REAL WORLD MINOR CRASHES IN THE UNITED STATES: A PILOT STUDY EXAMINING INJURY DIAGNOSES

60 billion. Including mild TBI and concussion, TBI’s are prevalent in soldiers returning from Iraq and Afghanistan as well as in domestic athletes. Long-term risks of single and cumulative head impact dosage may present in the form of post traumatic stress disorder (PTSD), depression, suicide, Chronic Traumatic Encephalopathy (CTE), dementia, Alzheimer’s and Parkinson’s diseases. Quantifying head impact dosage and understanding associated risk factors for the development of long-term sequelae is critical toward developing guidelines for TBI exposure and post-exposure management. The current knowledge gap between head impact exposure and clinical outcomes limits the understanding of underlying TBI mechanisms, including effective treatment protocols and prevention methods for soldiers and athletes. In order to begin addressing this knowledge gap, Cleveland Clinic is developing the “Intelligent Mouthguard” head impact dosimeter. Current testing indicates the Intelligent Mouthguard can quantify linear acceleration with 3% error and angular acceleration with 17% error during impacts ranging from 10g to 174g and 850rad/s2 to 10000rad/s2, respectively. Correlation was high (R2 > 0.99, R2 = 0.98, respectively). Near-term development will be geared towards quantifying head impact dosages in vitro, longitudinally in athletes and to test new sensors for possible improved accuracy and reduced bias. Long-term, the IMG may be useful to soldiers to be paired with neurocognitive clinical data quantifying resultant TBI functional deficits.

Development of a head impact monitoring “Intelligent Mouthguard”

INTRODUCTION There is no existing database to examine the types of injuries reported in minor motor vehicle rear impacts (MVRI) since currently used National Highway Traffic Safety Administration (NHTSA) databases like FARS, CIREN or NASS emphasize fatal, high severity and tow-away crashes. Additionally, there is no fully validated criterion in the United States that addresses spine injury threshold in MVRI. This lack of information is particularly alarming when considering there are approximately 272,000 “whiplash” injuries attributed to rear crashes in the U.S. every year. These injuries result in an annual medical burden in the U.S. economy of

Editorial: Leather football helmets

2.8-8.5 billion (the cost of rear fatal motor vehicle crashes is approximately