CHILDHOOD MOTOCROSS TRUNCAL INJURIES: HIGH VELOCITY, FOCAL FORCE TO THE CHEST AND ABDOMEN: A Cohort Study For peer review only

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1 CHILDHOOD MOTOCROSS TRUNCAL INJURIES: HIGH VELOCITY, FOCAL FORCE TO THE CHEST AND ABDOMEN: A Cohort Study Journal: Manuscript ID: bmjopen-0-00 Article Type: Research Date Submitted by the Author: -Jul-0 Complete List of Authors: Kennedy, Raelene; Mayo Clinic, General Surgery Potter, D. Dean; Mayo Clinic, Pediatric Surgery Osborn, John; Mayo Clinic, Trauma, Critical Care and General Surgery Zietlow, Scott; Mayo Clinic, Trauma, Critical Care and General Surgery Zarroug, Abdalla; Mayo Clinic, Pediatric Surgery Moir, Christopher; Mayo Clinic, Pediatric Surgery Ishitani, Michael; Mayo Clinic, Pediatric Surgery McIntosh, Amy; Mayo Clinic, Orthopedics <b>primary Subject Heading</b>: Surgery Secondary Subject Heading: Emergency medicine, Paediatrics Keywords: Trauma management < ORTHOPAEDIC & TRAUMA SURGERY, Paediatric orthopaedic & trauma surgery < PAEDIATRIC SURGERY, Paediatric intensive & critical care < PAEDIATRICS, Paediatric surgery < SURGERY : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

2 Page of July, 0 Dr. Trish Groves Editor in Chief Dear Dr. Groves, Attached is our manuscript entitled Childhood motocross truncal injuries: High velocity, focal force to the chest and abdomen. We wish to submit this for consideration of publication within. This is an original research article. This work has not previously been published. It has been presented at the Minnesota Surgical Society in September 00 and also as a poster at the 0 Annual CAPS meeting in Ottawa, Canada. All authors have had a significant contribution to this paper and have approved the final manuscript. We have no financial disclosures. Please send any questions or correspondence via to Dr. D. Dean Potter at potter.donald@mayo.edu. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

3 Page of Childhood motocross truncal injuries: High velocity, focal force to the chest and abdomen. Raelene Kennedy, M.D., D. Dean Potter, M.D., John B. Osborn, M.Sc., Scott Zietlow, M.D., Abdalla E. Zarroug, M.D., Christopher R. Moir, M.D., Michael B. Ishitani, M.D., Amy McIntosh M.D. Division of Pediatric Surgery, Mayo Clinic Rochester, Rochester, MN Division of Trauma, Critical Care and General Surgery, Mayo Clinic Rochester, Rochester, MN Department of Orthopedic Surgery, Mayo Clinic Rochester, Rochester, MN Short Title (Running Head): Childhood motocross truncal injury Corresponding author: D. Dean Potter, M.D. Division of Pediatric Surgery Mayo Clinic Rochester 00 First Street SW Rochester, MN 0 Phone: -- Fax: potter.donald@mayo.edu - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

4 Page of CHILDHOOD MOTOCROSS TRUNCAL INJURIES: HIGH VELOCITY, FOCAL FORCE TO THE CHEST AND ABDOMEN. A COHORT STUDY. Abstract Objectives: To review the need for operative intervention and critical care services for motocross truncal injuries in children. Design: Cohort. Retrospective review of patients identified via the hospital trauma registry. Setting: Our Level Pediatric Trauma Center serves motocross tracks. These patients require frequent medical care for injuries. Participants: All patients < years of age with truncal injuries sustained during motocross activities, between 000 and 0, were identified through the trauma registry. Primary and Secondary outcome measures: Operative intervention, ICU admission, length of stay, morbidity and demographics were reviewed. Results: Motocross injured children. Thirty (.%) were thoracic or abdominal injuries. Operative intervention was required in (%) patients. Mean ISS was.. ICU admission was required in % and average hospital LOS was. days. The most common injuries include pulmonary contusion, pneumothorax, spleen and liver lacerations. % of subjects suffered truncal injury from motocross on more than one occasion. Conclusions: Pediatric motocross-related truncal injuries are significant. Surgical intervention is required in % of patients. The lower ISS incurred from motocross combined with high surgical and ICU admission rates suggests focal high impact injuries to the chest and abdomen. Despite significant injury, % of motocross patients suffer recurrent injuries. Parents and children need injury prevention education. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

5 Page of Introduction Motocross is a popular recreational activity in Minnesota. There are motocross tracks in the state, with in the local region of our Level Pediatric Trauma Center. Motocross race events occur most weekends throughout the summer, with 00- youth registrants per race. Health care professionals at our rural, tertiary care hospital have noticed severe injuries in children and teens participating in motocross events. Specifically noted were abdominal and thoracic injuries, many of which required surgery and/or intensive care unit admission. Given that no studies have been published in children to date exploring the relationship between truncal injuries from motocross, this study was designed retrospectively review our experience and quantify those observations. We hypothesize that pediatric truncal injuries sustained during motocross require frequent operative intervention and admission to the intensive care unit (ICU). - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

6 Page of Materials and Methods All patients years of age and younger with truncal (abdomen and/or thorax) injuries sustained during motocross activities presenting to our institution between 000 and 0 were identified through our trauma registry. The trauma registry collects standardized data from all level and trauma activations presenting to the emergency department, as well as all hospital admissions due to trauma. Our hospital is a large tertiary care facility and level trauma center in rural Southeastern Minnesota. Cases were included for analysis if the injury was located in the thorax and/or abdomen and had visceral involvement. Isolated orthopedic fractures (ribs, clavicles, and vertebrae) and minor soft tissue injuries were excluded. Review of the medical record was performed for all cases. Demographic data collected included age and gender. Primary outcomes examined included anatomic injury location, operative procedure, hospital length of stay, intensive care unit (ICU) admission, injury severity score and mortality. Charts were also reviewed for subsequent or previous documentation of truncal injury from motocross. Research protocol was reviewed and approved by the Institutional Review Board at Mayo Clinic, Minnesota. All authors have contributed equally to this work. We have no conflicting interests to disclose. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

7 Page of Results The trauma registry identified pediatric motocross trauma patients over an year period, with 0 (.%) of these injuries to the chest and/or abdomen. Children ranged in age from to years of age. All patients were male (00%). There were no mortalities. Intensive care unit (ICU) admission was required in % of patients. Average ICU length of stay was. days (range to days). Overall mean hospital length of stay was. days (range to days). Average injury severity score (ISS) was. (range to ). Injuries included lung contusions, pneumothoraces, penetrating abdominal wall wounds, small bowel injuries, retroperitoneal hematomas, and spleen, kidney and liver lacerations (Table ). Boney injury was seen only in association with injury to the thorax and included fractures of the sternum, ribs, clavicles and vertebrae. These fractures were associated with underlying pulmonary contusions and pneumothoraces. The most common injuries (in descending order) were pneumothoraces, lung contusions and splenic lacerations. Nine of patients with thoracic injury had multiple injuries within the chest. Injury to the abdomen affected only a single abdominal site in all cases. Two patients had injury to both the chest and abdomen. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

8 Page of Table : Description of Injuries Injury Description Number of Patients (n) Percent Thorax patients % Pneumothorax 0 % Lung Contusion % Rib Fracture % Vertebral Fracture 0% Clavicle Fracture % Sternum Fracture % Abdomen patients % Spleen Laceration % Liver Laceration % Penetrating Wound to Abdominal Wall % Retroperitoneal Hematoma % Kidney Laceration % Small Bowel Injury % Multiple Injuries patients % Multiple Thoracic Injuries 0% Multiple Abdominal Injuries 0 0% Thoracic and Abdominal Injuries % Surgical intervention was required in % (n=) of patients. Operative procedures performed included exploratory laparotomy, splenectomy, tube thoracostomy and ureteral stent insertion and are summarized in Table. Table : Operative Procedures Operative Procedure Number of Patients (n) Percent Exploratory laparotomy 0% Splenectomy % Tube Thoracostomy % Ureteral Stent % Total Operative Patients % Upon chart review, it was noted that several individuals injured during motocross had repeat hospital visits for previous or subsequent motocross injuries sustained outside our study interval. Specifically,.% had recurrent truncal injuries from motocross recorded at our institution. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

9 Page of These injuries tended to be severe despite prior experience. Recidivism event details are available in Table. Table : Patient Recidivism Details Patient First Injury Second Injury Bilateral retroperitoneal hematomas Rib fractures and pneumothorax Rib, clavicle and scapula fracture with Pulmonary contusion pulmonary contusions Splenic injury requiring splenectomy Sternal fracture and pulmonary contusions Chest contusion Splenic injury requiring splenectomy - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

10 Page of Discussion Motocross is a competitive sport. In motocross events, children drive motorized vehicles, with or more horsepower, at upwards of highway speed, navigating sharp curves and flying over jumps. Not surprisingly, motocross can produce significant injury in children. Little published research is available pertaining to injuries from motocross, with even less for the pediatric population. However, no studies have been published to date specifically addressing truncal injuries in children due to motocross (i.e. injuries encountered by the Pediatric General Surgeon). A recent study from our institution explored pediatric motocross injuries and their economic implications (). The overall surgery rate was 0%, with % of surgeries being orthopedic in nature (). This study was consistent with others that have found the majority of injuries from motocross are typically orthopedic in nature, with the lower limb being the most frequent (-). This study found that % of general motocross injuries required admission to the hospital, with % going to the ICU (). Most of these ICU admissions are likely truncal injuries, as our study identified a % ICU admission rate for children with truncal injuries. Other studies indicate injuries to the chest range % to % and abdomen % to % in adult motocross injuries (, ). Pediatric data available in the literature pertain to recreational dirtbike use, with a paucity of information on competitive motocross for kids and teens. Description of truncal injury and treatment/surgery required has also not been detailed in previous publications. Our results suggest that pediatric motocross injuries involve the trunk in % of cases. The most common injuries were pulmonary contusions, pneumothoraces and spleen lacerations. The - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

11 Page 0 of majority of these injuries were managed successfully with non-operative care however % required operative intervention. Other studies have examined recreational motorbike or dirtbike injuries in children however it may not be accurate to compare recreational motorbike riding to competitive motocross. Motocross entails high speeds, with jumps and obstacles, and many racers nearby. Motocross therefore has theoretical potential for more significant and frequent injury. Robertson and Garrett examined pediatric motorbike injuries in Australia (). They determined an average ISS score of for all injuries from motorbike crashes. This is lower than our ISS of. for all motocross injuries (data not shown) and. for truncal trauma. Pomerantz et al. reviewed pediatric motorbike injuries in Ohio (). They found an average ISS of. and hospital length of stay. days, which is more consistent with our data. Our data indicate that truncal trauma is common in pediatric motocross injuries (.%). Truncal trauma appears more common in motocross riders than in children riding recreational motorbikes. Pomerantz et al. found truncal trauma in % of kids injured on motorbikes (), while Yanchar et al. found 0% truncal injuries in pediatric dirtbike injuries (). However, our pediatric data are similar to adult motocross studies. In a year review of motocross injuries, Gobbi et al. found truncal trauma in % of adult cases (). Gorski et al. found higher rates, with % chest and % abdominal injuries amongst adult motocross riders (). Physicians should have a high suspicion for truncal trauma in patients presenting after a motocross crash. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

12 Page of At our institution, over an year period, motocross injured children severely enough to warrant level to trauma activation and/or hospital admission. Furthermore, our data suggest that motocross can produce significant truncal trauma in children. In fact, % of injuries to the thorax or abdomen required operative intervention. More alarming is that % have suffered significant truncal trauma from motocross on more than one occasion. This data represents injuries presenting to our single hospital. The rate of recidivism may in fact be higher if treatment has also been sought elsewhere. It is interesting to note that motocross had the higher rate of truncal surgery (%) than general pediatric trauma would expect. Furthermore, % of patients required admission to the intensive care unit. However, average injury severity score remained low (.). The lower ISS and higher surgery and ICU admission rate incurred from motocross suggests focal high impact injuries to the chest and abdomen. When examining a child with chest or abdominal injury following motocross crash, physicians should be watchful for severe focal truncal injury in light of an otherwise low ISS. One in four of these children may require surgery. Protective equipment, such as chest guards and kidney belts, may play a role in preventing truncal trauma. Unfortunately, data pertaining to protective equipment worn at the time of injury was not available from our trauma registry. We are therefore unable to assess that hypothesis. Parents and children should be counseled about proper safety precautions and potential for severe internal injury during motocross activities. Further prospective studies evaluating safety practices during motocross events are underway : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

13 Page of References. Larson AN, Stans AA, Shaughnessy WJ, et al: Motocross morbidity: Economic cost and injury distribution in children. J Pediatr Orthop 00;():-.. Gorski TF, Gorski YC, McLeod, et al: Patterns of injury and outcomes associated with motocross accidents. Am Surgeon 00;(0):-.. Colburn NT and Meyer RD: Sports injury or trauma? Injuries of the competition off-road motorcyclist. Injury, Int J Care Injured 00;: 0-.. Yanchar NL, Kennedy R, Russell C: ATVs: motorized toys or vehicles for children? Inj Prev 00;:0-.. Pomerantz WJ, Gittelman MA, Smith GA: No license required: severe pediatric motorbikerelated injuries in Ohio. Pediatrics 00;():0-0.. Robertson J and Garrett P: Paediatric motorbike injuries: Do children riding motorbikes get the same injuries as those riding bicycles? ANZ J Surg 00;:-.. Gobbi A, Tuy B, Panuncialman I: The incidence of motocross injuries: a -year investigation. Knee Surg Sports Traumatol Arthrosec 00;: : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

14 CHILDHOOD MOTOCROSS TRUNCAL INJURIES: HIGH VELOCITY, FOCAL FORCE TO THE CHEST AND ABDOMEN Journal: Manuscript ID: bmjopen-0-00.r Article Type: Research Date Submitted by the Author: 0-Sep-0 Complete List of Authors: Kennedy, Raelene; Mayo Clinic, General Surgery Potter, D. Dean; Mayo Clinic, Pediatric Surgery Osborn, John; Mayo Clinic, Trauma, Critical Care and General Surgery Zietlow, Scott; Mayo Clinic, Trauma, Critical Care and General Surgery Zarroug, Abdalla; Mayo Clinic, Pediatric Surgery Moir, Christopher; Mayo Clinic, Pediatric Surgery Ishitani, Michael; Mayo Clinic, Pediatric Surgery McIntosh, Amy; Mayo Clinic, Orthopedics <b>primary Subject Heading</b>: Surgery Secondary Subject Heading: Emergency medicine, Paediatrics Keywords: Trauma management < ORTHOPAEDIC & TRAUMA SURGERY, Paediatric orthopaedic & trauma surgery < PAEDIATRIC SURGERY, Paediatric intensive & critical care < PAEDIATRICS, Paediatric surgery < SURGERY : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

15 Page of September, 0 Dr. Trish Grovs Editor in Chief Dear Dr. Groves, Attached is our revised manuscript entitled Childhood motocross truncal injuries: High velocity, focal force to the chest and abdomen. We appreciate the editors comments and recommendations and have made the appropriate revisions. Please send any questions or correspondence via to Dr. D. Dean Potter at potter.donald@mayo.edu. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

16 Page of Childhood motocross truncal injuries: High velocity, focal force to the chest and abdomen. Raelene Kennedy, M.D., D. Dean Potter, M.D., John B. Osborn, M.Sc., Scott Zietlow, M.D., Abdalla E. Zarroug, M.D., Christopher R. Moir, M.D., Michael B. Ishitani, M.D., Amy McIntosh M.D. Division of Pediatric Surgery, Mayo Clinic Rochester, Rochester, MN Division of Trauma, Critical Care and General Surgery, Mayo Clinic Rochester, Rochester, MN Department of Orthopedic Surgery, Mayo Clinic Rochester, Rochester, MN Short Title (Running Head): Childhood motocross truncal injury Corresponding author: D. Dean Potter, M.D. Division of Pediatric Surgery Mayo Clinic Rochester 00 First Street SW Rochester, MN 0 Phone: -- Fax: potter.donald@mayo.edu - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

17 Page of CHILDHOOD MOTOCROSS TRUNCAL INJURIES: HIGH VELOCITY, FOCAL FORCE TO THE CHEST AND ABDOMEN. Abstract Objectives: To review the need for operative intervention and critical care services for motocross truncal injuries in children. Design: Cohort. Retrospective review of patients identified via the hospital trauma registry. Setting: Our Level Pediatric Trauma Center serves motocross tracks. These patients require frequent medical care for injuries. Participants: All patients < years of age with truncal injuries sustained during motocross activities, between 000 and 0, were identified through the trauma registry. Primary and Secondary outcome measures: Operative intervention, ICU admission, length of stay, morbidity and demographics were reviewed. Results: Motocross injured children. Thirty (.%) were thoracic or abdominal injuries. Operative intervention was required in (%) patients. Mean ISS was.. ICU admission was required in % and average hospital LOS was. days. The most common injuries include pulmonary contusion, pneumothorax, spleen and liver lacerations. % of subjects suffered truncal injury from motocross on more than one occasion. Conclusions: Pediatric motocross-related truncal injuries are significant. Surgical intervention is required in % of patients. The lower ISS incurred from motocross combined with high surgical and ICU admission rates suggests focal high impact injuries to the chest and abdomen. Despite significant injury, % of motocross patients suffer recurrent injuries. Parents and children need injury prevention education. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

18 Page of Introduction Motocross is a popular recreational activity in Minnesota. There are motocross tracks in the state, with in the local region of our Level Pediatric Trauma Center. Motocross race events occur most weekends throughout the summer, with 00- youth registrants per race. Health care professionals at our rural, tertiary care hospital have noticed severe injuries in children and teens participating in motocross events. Specifically noted were abdominal and thoracic injuries, many of which required surgery and/or intensive care unit admission. Given that no studies have been published in children to date exploring the relationship between truncal injuries from motocross, this study was designed retrospectively review our experience and quantify those observations. We hypothesize that pediatric truncal injuries sustained during motocross require frequent operative intervention and admission to the intensive care unit (ICU). - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

19 Page of Materials and Methods All patients years of age and younger with truncal (abdomen and/or thorax) injuries sustained during motocross activities presenting to our institution between 000 and 0 were identified through our trauma registry. The trauma registry collects standardized data from all level and trauma activations presenting to the emergency department, as well as all hospital admissions due to trauma. Our hospital is a large tertiary care facility and level trauma center in rural Southeastern Minnesota. Cases were included for analysis if the injury was located in the thorax and/or abdomen and had visceral involvement. Isolated orthopedic fractures (ribs, clavicles, and vertebrae) and minor soft tissue injuries were excluded. Review of the medical record was performed for all cases by the first author of this paper. Demographic data collected included age and gender. Primary outcomes examined included anatomic injury location, operative procedure, hospital length of stay, intensive care unit (ICU) admission, injury severity score and mortality. Charts were also reviewed for subsequent or previous documentation of truncal injury from motocross. Research protocol was reviewed and approved by the Institutional Review Board at Mayo Clinic, Minnesota. All authors have contributed equally to this work. We have no conflicting interests to disclose. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

20 Page of Results The trauma registry identified pediatric motocross trauma patients over an year period, with 0 (.%) of these injuries to the chest and/or abdomen. Children ranged in age from to years of age. All patients were male (00%). There were no mortalities. Intensive care unit (ICU) admission was required in % of patients. Average ICU length of stay was. days (range to days). Overall mean hospital length of stay was. days (range to days). Average injury severity score (ISS) was. (range to ). Injuries included lung contusions, pneumothoraces, penetrating abdominal wall wounds, small bowel injuries, retroperitoneal hematomas, and spleen, kidney and liver lacerations (Table ). Boney injury was seen only in association with injury to the thorax and included fractures of the sternum, ribs, clavicles and vertebrae. These fractures were associated with underlying pulmonary contusions and pneumothoraces. The most common injuries (in descending order) were pneumothoraces, lung contusions and splenic lacerations. Nine of patients with thoracic injury had multiple injuries within the chest. Injury to the abdomen affected only a single abdominal site in all cases. Two patients had injury to both the chest and abdomen. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

21 Page of Table : Description of Injuries Injury Description Number of Patients (n) Percent Thorax patients % Pneumothorax 0 % Lung Contusion % Rib Fracture % Vertebral Fracture 0% Clavicle Fracture % Sternum Fracture % Abdomen patients % Spleen Laceration % Liver Laceration % Penetrating Wound to Abdominal Wall % Retroperitoneal Hematoma % Kidney Laceration % Small Bowel Injury % Multiple Injuries patients % Multiple Thoracic Injuries 0% Multiple Abdominal Injuries 0 0% Thoracic and Abdominal Injuries % Surgical intervention was required in % (n=) of patients. Operative procedures performed included exploratory laparotomy, splenectomy, tube thoracostomy and ureteral stent insertion and are summarized in Table. Table : Operative Procedures Operative Procedure Number of Patients (n) Percent Exploratory laparotomy 0% Splenectomy % Tube Thoracostomy % Ureteral Stent % Total Operative Patients % Upon chart review, it was noted that several individuals injured during motocross had repeat hospital visits for previous or subsequent motocross injuries sustained outside our study interval. Specifically,.% had recurrent truncal injuries from motocross recorded at our institution. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

22 Page of These injuries tended to be severe despite prior experience. Recidivism event details are available in Table. Table : Patient Recidivism Details Patient First Injury Second Injury Bilateral retroperitoneal hematomas Rib fractures and pneumothorax Rib, clavicle and scapula fracture with Pulmonary contusion pulmonary contusions Splenic injury requiring splenectomy Sternal fracture and pulmonary contusions Chest contusion Splenic injury requiring splenectomy - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

23 Page of Discussion Motocross is a competitive sport. In motocross events, children drive motorized vehicles, with or more horsepower, at upwards of highway speed, navigating sharp curves and flying over jumps. Not surprisingly, motocross can produce significant injury in children. Little published research is available pertaining to injuries from motocross, with even less for the pediatric population. However, no studies have been published to date specifically addressing truncal injuries in children due to motocross (i.e. injuries encountered by the Pediatric General Surgeon). A recent study from our institution explored pediatric motocross injuries and their economic implications (). The overall surgery rate was 0%, with % of surgeries being orthopedic in nature (). This study was consistent with others that have found the majority of injuries from motocross are typically orthopedic in nature, with the lower limb being the most frequent (-). This study found that % of general motocross injuries required admission to the hospital, with % going to the ICU (). Most of these ICU admissions are likely truncal injuries, as our study identified a % ICU admission rate for children with truncal injuries. Other studies indicate injuries to the chest range % to % and abdomen % to % in adult motocross injuries (, ). Pediatric data available in the literature pertain to recreational dirtbike use, with a paucity of information on competitive motocross for kids and teens. Description of truncal injury and treatment/surgery required has also not been detailed in previous publications. Our results suggest that pediatric motocross injuries involve the trunk in % of cases. The most common injuries were pulmonary contusions, pneumothoraces and spleen lacerations. The - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

24 Page 0 of majority of these injuries were managed successfully with non-operative care however % required operative intervention. Other studies have examined recreational motorbike or dirtbike injuries in children however it may not be accurate to compare recreational motorbike riding to competitive motocross. Motocross entails high speeds, with jumps and obstacles, and many racers nearby. Motocross therefore has theoretical potential for more significant and frequent injury. Robertson and Garrett examined pediatric motorbike injuries in Australia (). They determined an average ISS score of for all injuries from motorbike crashes. This is lower than our ISS of. for all motocross injuries (data not shown) and. for truncal trauma. Pomerantz et al. reviewed pediatric motorbike injuries in Ohio (). They found an average ISS of. and hospital length of stay. days, which is more consistent with our data. Our data indicate that truncal trauma is common in pediatric motocross injuries (.%). Truncal trauma appears more common in motocross riders than in children riding recreational motorbikes. Pomerantz et al. found truncal trauma in % of kids injured on motorbikes (), while Yanchar et al. found 0% truncal injuries in pediatric dirtbike injuries (). However, our pediatric data are similar to adult motocross studies. In a year review of motocross injuries, Gobbi et al. found truncal trauma in % of adult cases (). Gorski et al. found higher rates, with % chest and % abdominal injuries amongst adult motocross riders (). Physicians should have a high suspicion for truncal trauma in patients presenting after a motocross crash. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

25 Page of At our institution, over an year period, motocross injured children severely enough to warrant level to trauma activation and/or hospital admission. Furthermore, our data suggest that motocross can produce significant truncal trauma in children. In fact, % of injuries to the thorax or abdomen required operative intervention. More alarming is that % have suffered significant truncal trauma from motocross on more than one occasion. This data represents injuries presenting to our single hospital. The rate of recidivism may in fact be higher if treatment has also been sought elsewhere. It is interesting to note that motocross had the higher rate of truncal surgery (%) than general pediatric trauma would expect. Furthermore, % of patients required admission to the intensive care unit. However, average injury severity score remained low (.). The lower ISS and higher surgery and ICU admission rate incurred from motocross suggests focal high impact injuries to the chest and abdomen. When examining a child with chest or abdominal injury following motocross crash, physicians should be watchful for severe focal truncal injury in light of an otherwise low ISS. One in four of these children may require surgery. This study is limited by its retrospective design and small sample size. Our findings represent the pediatric motocross patients in southeast Minnesota, USA and may not apply to other populations. Likely not all injured motocross riders were captured by our hospital records. Less severely injured participants may have reported to smaller community hospitals for treatment. However, all level and traumas (those included in this study), should have been referred to our hospital as we are the only level trauma center in the region of motocross tracts. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

26 Page of Protective equipment, such as chest guards and kidney belts, may play a role in preventing truncal trauma. Unfortunately, data pertaining to protective equipment worn at the time of injury was not available from our trauma registry. We are therefore unable to assess that hypothesis. Parents and children should be counseled about proper safety precautions and potential for severe internal injury during motocross activities. Further prospective studies evaluating safety practices during motocross events are underway : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

27 Page of References. Larson AN, Stans AA, Shaughnessy WJ, et al: Motocross morbidity: Economic cost and injury distribution in children. J Pediatr Orthop 00;():-.. Gorski TF, Gorski YC, McLeod, et al: Patterns of injury and outcomes associated with motocross accidents. Am Surgeon 00;(0):-.. Colburn NT and Meyer RD: Sports injury or trauma? Injuries of the competition off-road motorcyclist. Injury, Int J Care Injured 00;: 0-.. Yanchar NL, Kennedy R, Russell C: ATVs: motorized toys or vehicles for children? Inj Prev 00;:0-.. Pomerantz WJ, Gittelman MA, Smith GA: No license required: severe pediatric motorbikerelated injuries in Ohio. Pediatrics 00;():0-0.. Robertson J and Garrett P: Paediatric motorbike injuries: Do children riding motorbikes get the same injuries as those riding bicycles? ANZ J Surg 00;:-.. Gobbi A, Tuy B, Panuncialman I: The incidence of motocross injuries: a -year investigation. Knee Surg Sports Traumatol Arthrosec 00;: : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

28 Page of September, 0 Dr. Trish Grovs Editor in Chief Dear Dr. Groves, Attached is our revised manuscript entitled Childhood motocross truncal injuries: High velocity, focal force to the chest and abdomen. We appreciate the editors comments and recommendations and have made the appropriate revisions. Please send any questions or correspondence via to Dr. D. Dean Potter at potter.donald@mayo.edu. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

29 Page of Childhood motocross truncal injuries: High velocity, focal force to the chest and abdomen. Raelene Kennedy, M.D., D. Dean Potter, M.D., John B. Osborn, M.Sc., Scott Zietlow, M.D., Abdalla E. Zarroug, M.D., Christopher R. Moir, M.D., Michael B. Ishitani, M.D., Amy McIntosh M.D. Division of Pediatric Surgery, Mayo Clinic Rochester, Rochester, MN Division of Trauma, Critical Care and General Surgery, Mayo Clinic Rochester, Rochester, MN Department of Orthopedic Surgery, Mayo Clinic Rochester, Rochester, MN Short Title (Running Head): Childhood motocross truncal injury Corresponding author: D. Dean Potter, M.D. Division of Pediatric Surgery Mayo Clinic Rochester 00 First Street SW Rochester, MN 0 Phone: -- Fax: potter.donald@mayo.edu - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

30 Page of CHILDHOOD MOTOCROSS TRUNCAL INJURIES: HIGH VELOCITY, FOCAL FORCE TO THE CHEST AND ABDOMEN. Abstract Objectives: To review the need for operative intervention and critical care services for motocross truncal injuries in children. Design: Cohort. Retrospective review of patients identified via the hospital trauma registry. Setting: Our Level Pediatric Trauma Center serves motocross tracks. These patients require frequent medical care for injuries. Participants: All patients < years of age with truncal injuries sustained during motocross activities, between 000 and 0, were identified through the trauma registry. Primary and Secondary outcome measures: Operative intervention, ICU admission, length of stay, morbidity and demographics were reviewed. Results: Motocross injured children. Thirty (.%) were thoracic or abdominal injuries. Operative intervention was required in (%) patients. Mean ISS was.. ICU admission was required in % and average hospital LOS was. days. The most common injuries include pulmonary contusion, pneumothorax, spleen and liver lacerations. % of subjects suffered truncal injury from motocross on more than one occasion. Conclusions: Pediatric motocross-related truncal injuries are significant. Surgical intervention is required in % of patients. The lower ISS incurred from motocross combined with high surgical and ICU admission rates suggests focal high impact injuries to the chest and abdomen. Despite significant injury, % of motocross patients suffer recurrent injuries. Parents and children need injury prevention education. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

31 Page of Introduction Motocross is a popular recreational activity in Minnesota. There are motocross tracks in the state, with in the local region of our Level Pediatric Trauma Center. Motocross race events occur most weekends throughout the summer, with 00- youth registrants per race. Health care professionals at our rural, tertiary care hospital have noticed severe injuries in children and teens participating in motocross events. Specifically noted were abdominal and thoracic injuries, many of which required surgery and/or intensive care unit admission. Given that no studies have been published in children to date exploring the relationship between truncal injuries from motocross, this study was designed retrospectively review our experience and quantify those observations. We hypothesize that pediatric truncal injuries sustained during motocross require frequent operative intervention and admission to the intensive care unit (ICU). - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

32 Page of Materials and Methods All patients years of age and younger with truncal (abdomen and/or thorax) injuries sustained during motocross activities presenting to our institution between 000 and 0 were identified through our trauma registry. The trauma registry collects standardized data from all level and trauma activations presenting to the emergency department, as well as all hospital admissions due to trauma. Our hospital is a large tertiary care facility and level trauma center in rural Southeastern Minnesota. Cases were included for analysis if the injury was located in the thorax and/or abdomen and had visceral involvement. Isolated orthopedic fractures (ribs, clavicles, and vertebrae) and minor soft tissue injuries were excluded. Review of the medical record was performed for all cases by the first author of this paper. Demographic data collected included age and gender. Primary outcomes examined included anatomic injury location, operative procedure, hospital length of stay, intensive care unit (ICU) admission, injury severity score and mortality. Charts were also reviewed for subsequent or previous documentation of truncal injury from motocross. Research protocol was reviewed and approved by the Institutional Review Board at Mayo Clinic, Minnesota. All authors have contributed equally to this work. We have no conflicting interests to disclose. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

33 Page of Results The trauma registry identified pediatric motocross trauma patients over an year period, with 0 (.%) of these injuries to the chest and/or abdomen. Children ranged in age from to years of age. All patients were male (00%). There were no mortalities. Intensive care unit (ICU) admission was required in % of patients. Average ICU length of stay was. days (range to days). Overall mean hospital length of stay was. days (range to days). Average injury severity score (ISS) was. (range to ). Injuries included lung contusions, pneumothoraces, penetrating abdominal wall wounds, small bowel injuries, retroperitoneal hematomas, and spleen, kidney and liver lacerations (Table ). Boney injury was seen only in association with injury to the thorax and included fractures of the sternum, ribs, clavicles and vertebrae. These fractures were associated with underlying pulmonary contusions and pneumothoraces. The most common injuries (in descending order) were pneumothoraces, lung contusions and splenic lacerations. Nine of patients with thoracic injury had multiple injuries within the chest. Injury to the abdomen affected only a single abdominal site in all cases. Two patients had injury to both the chest and abdomen. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

34 Page 0 of Table : Description of Injuries Injury Description Number of Patients (n) Percent Thorax patients % Pneumothorax 0 % Lung Contusion % Rib Fracture % Vertebral Fracture 0% Clavicle Fracture % Sternum Fracture % Abdomen patients % Spleen Laceration % Liver Laceration % Penetrating Wound to Abdominal Wall % Retroperitoneal Hematoma % Kidney Laceration % Small Bowel Injury % Multiple Injuries patients % Multiple Thoracic Injuries 0% Multiple Abdominal Injuries 0 0% Thoracic and Abdominal Injuries % Surgical intervention was required in % (n=) of patients. Operative procedures performed included exploratory laparotomy, splenectomy, tube thoracostomy and ureteral stent insertion and are summarized in Table. Table : Operative Procedures Operative Procedure Number of Patients (n) Percent Exploratory laparotomy 0% Splenectomy % Tube Thoracostomy % Ureteral Stent % Total Operative Patients % Upon chart review, it was noted that several individuals injured during motocross had repeat hospital visits for previous or subsequent motocross injuries sustained outside our study interval. Specifically,.% had recurrent truncal injuries from motocross recorded at our institution. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

35 Page of These injuries tended to be severe despite prior experience. Recidivism event details are available in Table. Table : Patient Recidivism Details Patient First Injury Second Injury Bilateral retroperitoneal hematomas Rib fractures and pneumothorax Rib, clavicle and scapula fracture with Pulmonary contusion pulmonary contusions Splenic injury requiring splenectomy Sternal fracture and pulmonary contusions Chest contusion Splenic injury requiring splenectomy - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

36 Page of Discussion Motocross is a competitive sport. In motocross events, children drive motorized vehicles, with or more horsepower, at upwards of highway speed, navigating sharp curves and flying over jumps. Not surprisingly, motocross can produce significant injury in children. Little published research is available pertaining to injuries from motocross, with even less for the pediatric population. However, no studies have been published to date specifically addressing truncal injuries in children due to motocross (i.e. injuries encountered by the Pediatric General Surgeon). A recent study from our institution explored pediatric motocross injuries and their economic implications (). The overall surgery rate was 0%, with % of surgeries being orthopedic in nature (). This study was consistent with others that have found the majority of injuries from motocross are typically orthopedic in nature, with the lower limb being the most frequent (-). This study found that % of general motocross injuries required admission to the hospital, with % going to the ICU (). Most of these ICU admissions are likely truncal injuries, as our study identified a % ICU admission rate for children with truncal injuries. Other studies indicate injuries to the chest range % to % and abdomen % to % in adult motocross injuries (, ). Pediatric data available in the literature pertain to recreational dirtbike use, with a paucity of information on competitive motocross for kids and teens. Description of truncal injury and treatment/surgery required has also not been detailed in previous publications. Our results suggest that pediatric motocross injuries involve the trunk in % of cases. The most common injuries were pulmonary contusions, pneumothoraces and spleen lacerations. The - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

37 Page of majority of these injuries were managed successfully with non-operative care however % required operative intervention. Other studies have examined recreational motorbike or dirtbike injuries in children however it may not be accurate to compare recreational motorbike riding to competitive motocross. Motocross entails high speeds, with jumps and obstacles, and many racers nearby. Motocross therefore has theoretical potential for more significant and frequent injury. Robertson and Garrett examined pediatric motorbike injuries in Australia (). They determined an average ISS score of for all injuries from motorbike crashes. This is lower than our ISS of. for all motocross injuries (data not shown) and. for truncal trauma. Pomerantz et al. reviewed pediatric motorbike injuries in Ohio (). They found an average ISS of. and hospital length of stay. days, which is more consistent with our data. Our data indicate that truncal trauma is common in pediatric motocross injuries (.%). Truncal trauma appears more common in motocross riders than in children riding recreational motorbikes. Pomerantz et al. found truncal trauma in % of kids injured on motorbikes (), while Yanchar et al. found 0% truncal injuries in pediatric dirtbike injuries (). However, our pediatric data are similar to adult motocross studies. In a year review of motocross injuries, Gobbi et al. found truncal trauma in % of adult cases (). Gorski et al. found higher rates, with % chest and % abdominal injuries amongst adult motocross riders (). Physicians should have a high suspicion for truncal trauma in patients presenting after a motocross crash. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.

38 Page of At our institution, over an year period, motocross injured children severely enough to warrant level to trauma activation and/or hospital admission. Furthermore, our data suggest that motocross can produce significant truncal trauma in children. In fact, % of injuries to the thorax or abdomen required operative intervention. More alarming is that % have suffered significant truncal trauma from motocross on more than one occasion. This data represents injuries presenting to our single hospital. The rate of recidivism may in fact be higher if treatment has also been sought elsewhere. It is interesting to note that motocross had the higher rate of truncal surgery (%) than general pediatric trauma would expect. Furthermore, % of patients required admission to the intensive care unit. However, average injury severity score remained low (.). The lower ISS and higher surgery and ICU admission rate incurred from motocross suggests focal high impact injuries to the chest and abdomen. When examining a child with chest or abdominal injury following motocross crash, physicians should be watchful for severe focal truncal injury in light of an otherwise low ISS. One in four of these children may require surgery. This study is limited by its retrospective design and small sample size. Our findings represent the pediatric motocross patients in southeast Minnesota, USA and may not apply to other populations. Likely not all injured motocross riders were captured by our hospital records. Less severely injured participants may have reported to smaller community hospitals for treatment. However, all level and traumas (those included in this study), should have been referred to our hospital as we are the only level trauma center in the region of motocross tracts. - : first published as 0./bmjopen-0-00 on November 0. Downloaded from on 0 October 0 by guest. Protected by copyright.