SLIDE 1: Pelvic and Thoracic Injuries in Nearside Impact Crashes: Analysis of Contributory Factors Allan Tencer, Rob Kaufman, Charles Mock Seattle CIREN team And Carol Conroy San Diego CIREN team SLIDE 2: Goal of This Study To determine whether vehicle design factors relate to thoracic and pelvic injuries from near-side impacts SLIDE 3: Background * Side impacts comprise about 32% of all vehicle crashes with occupants experiencing AIS 3+ injuries. * Thorax and pelvis are the most likely regions to be injured in near-side impacts (Samaha,’03) * Thoracic and pelvic injuries are probably the result of a limited stroke punch intrusion of the door, (Lau,’91 Chung ‘99). * The predominant injurious contact in thoracic and pelvic injuries is the door (Samaha, ‘03). SLIDE 4: Background – Variables Affecting Injury Crash variables - masses of both vehicles (Terrel, 18th ESV, ’03) - angle of impact - speed of bullet vehicle - Stiffness of both vehicles - Height of contact region on door Occupant variables - stature of occupant (Samaha 18th ESV, ’03) - location of occupant - restraint use - age of occupant (Austin 18th ESV, ’03) SLIDE 5: Vehicle Design Variables (1) 2001 Toyota Sienna Weight = 2029 kg Door crush = 29.7 cm Driver TTI = 69 pelvic g = 94 No side airbag (2) 2002 Toyota Tundra Weight = 2229 kg Door crush = 29.8 cm Driver TTI = 22 pelvic g =27 No side airbag SLIDE 6: Background –Vehicle Variables? Vehicle weight Maximum door intrusion (Chung ’99) Location of maximum door intrusion Peak door acceleration Peak door velocity (Morris, ’01,Viano ‘89) Peak relative door to vehicle velocity Wheelbase (related to vehicle stiffness?) Armrest (panel) stiffness (Rouhana ‘89, Viano ‘91, Deng ‘96, Cavanaugh ‘96, Daniel ’95, Morris ‘01) Dummy H-point to door horizontal distance (Morris,’01) Deployed thoracic airbag (thoracic injuries) Stiff center console (pelvic injuries) SLIDE 7: Basic Question Which vehicle variables relate to dummy accelerations in side impact collisions? SLIDE 8: METHODS NCAP side impact data - Standard moving deformable barrier mass, height, angle, and velocity - “Occupant” standard DOT SID - Peak pelvic g and TTI determined as function of vehicle related variables - Reports on 165 vehicles available at www.dms.dot.gov docket 3835 SLIDE 9: Methods – Vehicle Door Measurements SLIDE 10: Methods – CIREN and NASS CIREN * Scene inspection * Vehicle damage, restraint use, PDOF, DV * Occupant interior contact locations * Medical records, x-rays, imaging studies of injuries NASS * NASS-CDS database * side impacts, amount of door intrusion * highest AIS (MAIS) score of three regions determined SLIDE 11: Results – CIREN Examples SLIDE 12: CIREN Side Impact Data and Case Reviews SLIDE 13: Lateral Impact Mechanism Reviews Intrusion = Injury skeletal diagrams, indicating locations of: - thorax - abdominal - lateral pelvis - bilateral pelvis - combination SLIDE 14: Case Review Pre-Standard - combination intrusion injury - crash scene diagram SLIDE 15: Case Review [exterior vehicle photos post crash] 90's compact sedan SLIDE 16: [interior photos post crash] Lateral door intrusion at chest and pelvis SLIDE 17: Lower Lateral Door Intrusion - Left acetabular fx - Lower lateral door intrusion SLIDE 18: Injuries AIS: 2 REGION: head INJURY: concussion AIS: 2 REGION: spine INJURY: c1 fracture (non-displaced) AIS: 4 REGION: chest INJURY: L ribs fractures 3-8 with hemothorax pulmonary contusion ruptured L diaphragm AIS: 3 REGION: pelvis INJURY: sacral fx AIS: 3 REGION: pelvis INJURY: L acetabular Fx ISS = 29 SLIDE 19: Side Impact Standard Improvements [photos] Use of side impact beams in doors SLIDE 20: Case Review Protection From Side Impact Beams - 1997 Compact 2HB - Minimal intrusion - No injury to front right restrained passenger SLIDE 21: Side Impacts From Larger Vehicles Impact Above Support Beams SLIDE 22: Upper Door Panel Intrusion [photo - 1998 Subaru Impreza vs. SUV] Most light trucks, vans, and SUVs will collapse the upper door panel, and even override the support beam SLIDE 23: Door Intrusion - Thoracic Injuries SLIDE 24: Case Review Scene - diagram of crash path - "look back" path of travel [photo] SLIDE 25: Case Review [photo - post-crash - Compact Sedan] - Front Seat Passenger - 74 yr. , Male - Lap/Shoulder belt - Struck by a large pickup - Lateral Direction of Force SLIDE 26: Upper Door Panel Intrusion Case Review [post-crash photos, interior/exterior, front passenger side] Compact sedan struck by large pickup truck SLIDE 27: Upper Door Panel Intrusion Case Review diagram r-B pillar, R side interior, R window frame as points of contact w/passenger photo indicating locations of points of contact SLIDE 28: Injuries AIS: 2 REGION: head INJURY: scalp lacertaion AIS: 3 REGION: head INJURY: R subarachnoid bleed/contusion- parietal/occipital AIS: 4 REGION: chest INJURY: rib fxs: L 1-3, R 3-9 w/R pneumothorax AIS: 2 REGION: abdomen INJURY: R perinephric hematoma small AIS: 2 REGION: abdomen INJURY: pancreatic head lac ISS = 29 SLIDE 29: Hospital Course 77 year old restrained male. Confused at scene; intubated. Day 1: Exploratory laparotomy: Small hemoperitoneum, Small R perinephric hematoma Day 2-25: Prolonged respiratory failure: Pneumonia Tracheostomy on day 12 Trach pulled on day 25 Day 26: Transfer to Geriatrics Day 32: Transfer to Rehab SLIDE 30: CIREN Thoracic injury summary - copy SLIDE 31: Side Impact - Abdominal Injuries (Associated With the Armrest) SLIDE 32: Abdominal Injury Case Review 90's sedan Delta V = 15 mph Front Right Pass. Lap/Shoulder belt 71 yr. , Female SLIDE 33: Abdominal Injury Case Review Injuries associated with armrest: R kidney laceration Liver laceration Other: Splenic laceration Flail chest ruptured aorta SLIDE 34: Abdominal Armrest Injury Case Review 1998 Jeep Grand Cherokee SLIDE 35: Scene Diagram SLIDE 36: Vehicle Damage Door Extrication - low profile Delta V = 15 mph PDOF = -80 SLIDE 37: Demographic - Interior Contacts Driver Near side SS214 Unrestrained 30 yr., Female 5’8”, 140 lbs. SLIDE 38: Intrusions Left B pillar - 22cm - Lat Driver Door - 16cm - Lat Roof rail - 12cm - Lat SLIDE 39: Occupant Contacts - Upper Door Panel Scuff - Protruding Armrest scuffed - B pillar / Door panel cracked SLIDE 40: Treatment - Hospital Course 28 year old Female: Unrestrained in side impact. Alert at scene. Tachypneic (RR 40); tachycardic (125); SBP 100. Intubated in field. Initial Evaluation: Intubated, BP 145/108 L eye brow laceration Hospital Course: Abdominal CT: small liver and spleen lacs Extubated on day of admission Nonoperative management of pelvic fx Day 6: Discharged home (WB as tolerated) SLIDE 41: Injuries Face AIS L eye brow laceration 1 Chest L rib fxs (2-12) w/hemothorax 4 Abdomen L liver laceration 2 Splenic laceration 2 Lower Extremity L iliac crest fx (comminuted) 3 MAIS = 4 ISS = 29 SLIDE 42: Injury Contacts Observation Summary L Ribs 2-12 w/ hemothorax L sup/inf splenic lacerations L liver laceration L iliac wing fracture L pubic ring fracture SLIDE 43: [copy] CIREN abdominal injury summary: SLIDE 44: Side Impacts and Pelvic Injuries SLIDE 45: Pelvic Fracture Case Review SLIDE 46: Door Panel Intrusion SLIDE 47: Pelvic Fractures SLIDE 48: Lower Lateral Door Intrusion Associated With Pelvic Fractures [post-crash vehicle photos] injury: Comminuted pubic rami fracture SLIDE 49: [interior & exterior post-crash photos] Left side impact with Light Truck Unrestrained Driver SLIDE 50: [diagram of crash scene] Case Vehicle - 2001 Toyota Tacoma Struck by a 1994 Toyota Pickup [post crash exterior photo of case vehicle] Case occupant - 21 year old, female Front right passenger - Lap/shoulder belt Bilateral Pelvic injuries SLIDE 51: Vehicle Inspection [post crash photos] Smash Missing-DV = 30kph/18.6mph BES = 39kph/24.4mph Lateral PDOF SLIDE 52: [post-crash interior photos] Door panel intrusion = 45 cm/17.7inches Contact evidence on door/center console SLIDE 53: [post-crash photo] Case Vehicle - 2001 Toyota Tacoma SLIDE 54: Pelvis Comminuted fracture of the superior ramus of the right obturator ring which extends into the pubic symphysis. The fracture also extends into the inferior ramus. Comminuted fracture within the superior ramus of the left obturator ring extending into the pubic symphysis SLIDE 55: CIREN Pelvic Injury Summary (copy) SLIDE 56: San Diego CIREN Project Principal Investigators: David B. Hoyt, MD, FACS Brent Eastman, MD, FACS Presenter: Carol Conroy, MPH, PhD SLIDE 57: Research Question Are vehicles with raised center consoles associated with pelvic injury in nearside crashes? SLIDE 58: Selection Criteria NASS CDS and CIREN databases used Identify vehicles with raised center consoles - Assumed no change over +/- 2 model years - Assumed console standard equipment - Only 1998-2004 model years included SLIDE 59: Selection Criteria Only nearside impact crashes Only drivers or front right seat passengers included Only pelvic and hip injuries included SLIDE 60: Methods Missing data excluded from analyses Injury assessed by Abbreviated Injury Scale (AIS) Total Delta V used to assess speed at impact BES used when Total Delta V was missing SLIDE 61: Profile : Occupants with moderate (AIS 2) and serious (AIS 3) pelvic injury in nearside crashes Mean Age and range Console (41 occupants): 40 years (15-89 yrs) No Console / 21 Occupants: 43 years (15-80 yrs) Gender Console (41 occupants): 33 (80% women) No Console (21 Occupants): 11 (52% women) Single pelvic injury Console (41 occupants): 16 (39%) No Console (21 Occupants): 8 (38%) Driver Console (41 occupants): 29 (71%) No Console (21 Occupants): 13 (62%) Seatbelt Use Console (41 occupants): 36 (88%) No Console (21 Occupants): 19 (90%) Total Delta V (kmph) Console (41 occupants): mean 36/median 33 No Console (21 Occupants): mean 35/median 31 SLIDE 62: Moderate (AIS 2) and serious (AIS 3) pelvic injury in nearside crashes by magnitude of intrusion [bar chart] SLIDE 63: Limitations * Results may not be representative * Small sample size * Possible misclassification bias of console status * NASS intrusion is measured at the maximum point of intrusion on the door panel May not be at the occupant’s seat location SLIDE 64: Conclusion This exploratory study found it may be important to continue researching the role of consoles and pelvic injury in nearside crashes. SLIDE 65: Results – CIREN Summary Thoracic injuries, AIS of 4.2, door panel main injury source, intrusion 34cm, DV of 25 mph. Injuries multiple rib fractures with hemothorax, or pneumothorax, with lung contusions and lacerations. Abdominal injuries, AIS of 3.3 armrest main injury source, intrusion 30cm, DV 23 mph. Injuries, 9 spleen lacerations or contusions, 3 liver lacerations or contusions, 3 kidney contusions, 2 diaphragm lacerations, and 2 retroperitoneal hemorrhage. Pelvic injuries, AIS of 3, door panel main injury source, intrusion 25cm, DV 22 mph. Injuries included pelvic fx with 11 involving the sacrum. SLIDE 66: Results - Vehicle Variables and Pelvic g [scatter chart] Vehicle weight, door intrusion, wheelbase correlate to pelvic g All variables explain about 58% of pelvic g variation SLIDE 67: CIREN Example and Console Data Pelvic Acceleration and Console Trapping SLIDE 68: Results - Peak Pelvic g v Center Console photos - dummies without center consoles, 69.4g sd = 19.7g, n = 41 with center consoles, 77.3g sd = 21.8g, n = 96 (p = 0.05) SLIDE 69: Results - Vehicle Variables and NCAP Thoracic Trauma Index (TTI) [scatter chart] Vehicle weight and max door velocity correlate to TTI All variables explain about 41% of TTI variation SLIDE 70: Results – NCAP TTI and Thoracic Airbags Photos: without thoracic airbag, 63.7g sd = 20.7g, n = 108 with thoracic airbag, 55.6gsd = 13.7g, n = 54 (p = 0.003) SLIDE 71: Results - Is Door Intrusion Related to Vehicle Weight or Wheelbase? [2 scatter charts] Door intrusion, weak correlation to wheelbase (r2 = 0.15) Door intrusion, none to vehicle weight (r2 = 0.003, NS) SLIDE 72: Results – Does Peak Pelvic g Correlate to Peak TTI? [scatter chart] SLIDE 73: Results – NASS MAIS v Door Intrusion [line chart] SLIDE 74: Discussion - Limitations NCAP tests, moving barrier simulates smaller vehicle NCAP doesn’t consider door beam over-ride from high SUV and truck bumpers More biofidelic dummies than DOT-SID available TTI may not correlate well with actual injuries Effects of occupant stature and age not considered NASS, plot of data only of those in group who were injured (ie AIS 1+) SLIDE 75: Summary of Findings For a given vehicle weight, door intrusion, wheelbase correlate to pelvic g, and door velocity to TTI Vehicle variables studied only account for 41% of TTI, 58% of pelvic g variation A center console increases peak pelvic g A thoracic airbag lowers peak TTI Real-world crash studies also show correlation of door intrusion and thoracic and pelvic injury Door intrusion is not directly related to vehicle weight but increases with greater wheelbase SLIDE 76: Future Work There is still considerable debate over appropriate chest injury criteria, Favg * Cmax, Cmax, stored energy (Cheung ’99) Using highly detailed CIREN crash data and data from equivalent NCAP tests, to model actual crashes and compare real life injuries to crash dummy measurements in the same crash