Device to Prevent Cervical Spinal Cord Injury in Football PlayersGroup members: Laura Sanchez, Joseph Iskandar, Hanzhi ZhaoGroup Mentor: Dr. Jack Engsberg

Presenting: Laura Sanchez

Project Scope Background

Cervical spinal cord injury (CSCI) is caused by trauma that fractures or displaces vertebrae, damaging the spinal cord and the nerve roots.

The cervical region of the spine is the weakest, and more than half of all cases of spinal cord injury (SCI) in the U.S. and Canada involve injuries to this region. 

Project Scope Background

Approximately 13,000 people sustain SCI in North America each year, and 10% of these occur in activities that require the use of a helmet, ie. football, hockey, etc.5

The American Association of Neurological Surgeons estimated that 10% to 15% of all football players sustain some sort of SCI at some point in their career.1,7

The most frequent CSCI in football is neurapraxia of the nerve roots or brachial plexus (C5-C8). ½ of the members of a football team

report at least one such episode during a season.1

Occurs most often in linemen, defensive ends, and linebackers.1

Occurs when the shoulder is depressed and there is lateral head flexion.1

Project Scope Background

Example of cervical spinal cord injury1

SCI oftentimes results in transient or permanent quadriplegia (acute paralysis of all four extremities).2

Normal spinal cord posture consists of an arc of vertebral bodies that allow axial forces to dissipated evenly across each level.2

At 30o hyperflexion the cervical region becomes a straight column.2 Axial forces cannot be dissipated evenly,

leading to fracture and/or displacement of vertebrae resulting in cervical spinal cord damage.

Project Scope Background

Summary of Problems

Head-first impacts and impacts causing rotation of the neck are dangerous because the vertebral column is subjected to forces capable of causing displacement and fracture.

Football helmets aid in protecting against brain injury but not CSCI.

There is no gear available that protects or prevents against CSCI and many of the cases have no immediate cure.

Need

This device is targeted toward a general population of football players at the highschool, collegiate, and professional levels.

Approximately 1.2 million players participate at the highschool football level and 200,000 at the collegiate and professional levels.1

The NCAA has 119 D-1A football teams and approximately 617 teams in all divisions (~62,000 players).3

The NFL has 32 teams with 53 men roster (~1700 players).4

Purpose of the Design

Create a device capable of protecting football players from sustaining cervical spinal cord injuries.

PRO-NECK-TORTM

Nelson, T.S, Cripton P.A. “White Paper: A helmet for prevention and mitigation of spinal column and spinal cord injuries in Head First Impact.” (2008). Web.

Based upon the idea of axial loads to the head and neck during head-on collision impacts in sports such as football and hockey.5

Uses a double shell design with mechanical guides connecting the two shells which guide the head by using pistons reducing the impulse over a longer period of time so there’s less instantaneous force on the neck.5

Pro-Neck-TorTM

Pro-Neck-TorTM

Key feature is that the rotating technology is induced only upon impact.5

Creates a bending response that allows kinetic energy and collision force to be dissipated throughout the tissues of the neck and torso.

SCIBID

Engsberg J.D, Strandeven J.W, Shurtleff T.L, Tricamo J.M, Landau W.M. “Spinal cord and brain injury protection: testing concept for a protective device.” Nature (2009). 47, 634-639.

SCIBID

Direct relief of head impact by head shield on thoracic jacket.6

Plastic foam lining that supplies extra protection from traditional helmet.6

Limits skull and cervical spine movement.6

Restricts axial compression of cervical spine.6

HANS

HANS device. Hans Performance products. http://hansdevice.com/site/index.html

HANS

Also known as the head and neck support device utilized in car racing for safety.

Attached to the helmet via anchors on both sides instead of being attached to the body or any part of the car.8

Main injuries HANS protects against are the whiplash injury and skull fractures.8

Reduces collision energy that causes the hyperflexion of the head by about 80%.8

LEATT Brace

Leatt brace. 2004-2010 Leatt Corporation. http://www.leatt-brace.com/

LEATT Brace

Designed to be worn by motorcycle, motocross, and karting drivers.

Protects against: hyperflexion, hyperextension, lateral hyperflexion, axial loading or bending of the neck, and posterior hypertranslation.9

Re-directs the impact force and energy from the helmet, head and neck onto the shoulders, chest and back.9

Specific Design Requirements

The main principle of the device is: FIXATION

Allowance of complete freedom of motion of the head during normal play.

Size and ease of assembly are also necessary factors to consider.

Specific Design Requirements

Product cannot weigh more than 0.5 to 1 kg since it will be an addition to the gear and it will be supported by the head and shoulders.

Accelerometers or force transducers may be needed to measure either impact force or acceleration threshold.

Low Cost.

Description Measurements

Weight of Average Human Head10,11

4.5–5 kg

Percent weight of head relative to body10,11

7.3%

Distance from the center of gravity of the skull to C6/C7

14 cm

Weight of typical adult football helmet12

~3kg

Weight of other gear12 11.33 kg

Rotation of head from mid-sagittal plane

~80o to 85o

Preliminary Analyses

Equipment measurements taken were the following: Helmet:

17 cm across the jaw. 31 cm from face mask to back of the

helmet. Shoulder Pad:

16 cm from the right shoulder to the left shoulder.

21 cm from the front to the back.

Preliminary Analyses

The average force experienced resulting from a concussion-causing collision is 90-100 g-force and for spinal cord injury it is 114 g-force.13

During a collision that results in a cervical spinal cord injury, the rotational acceleration of the head reaches 3318 rad/sec2.14

Preliminary Analyses

Preliminary Design Schedule

October 1, 2011- Completing a Pugh chart with all possible options to funnel our idea further.

October 5, 2011- Have an operational web page.

October 12, 2011- Have completed illustrations and specs of initial design.

October 20, 2011- Finalize progress report and preparation for presentation.

Current Team Organization

Laura Sanchez- Preliminary Oral Report Patent and related research to product design

Hanzhi Zhao- Progress Oral Report Mathematical calculations

Joseph Iskandar- Final Oral Report CAD illustrations

Overall, we divide the tasks evenly according to each person’s strengths.

QUESTIONS?

References1. Thomas, Bruce E., Geoffrey M. McCullen, and Hansen A. Yuan. "Cervical Spine Injuries in Football Players."

Journal of the American Academy of Orthopaedic Surgeons 7.5 (1999). Web.2. O'Connor, Francis G. Sports Medicine: Just the Facts. New York: McGraw-Hill, Medical Pub. Division, 2005. Google

Books.3. NCAA Football. NCAA, 2011. Web. http://www.ncaafootball.com/.4. NFL.com - Official Site of the National Football League. NFL Enterprises LLC, 2011. Web. http://www.nfl.com/. 5. Nelson T.S, Cripton P.A. “White Paper: A helmet for prevention and mitigation of spinal column and spinal cord

injuries in Head First Impact.” (2008). Web. 6. Engsberg J.D, Strandeven J.W, Shurtleff T.L, Tricamo J.M, Landau W.M. “Spinal cord and brain injury protection:

testing concept for a protective device.” Nature (2009). 47, 634-639. 7. American Association of Neurological Surgeons. Patient Information: Sports-Related Neck Injury. July 2010.

http://aans.org/en/patient%20information/conditions%20and%20treatments/sports-related%20neck%20injury.aspx

8. HANS device. Hans Performance products. http://hansdevice.com/site/index.html 9. Leatt brace. 2004-2010 Leatt Corporation. http://www.leatt-brace.com/ 10. Hay, James G. (1993). The Biomechanics of Sports Techniques. San Francisco, CA: Benjamin-Cummings Pub. Co.11. Clauser, C.E., McConville, J.T., Young, J.W., (1969). Weight, volume, and center of mass of segments of the

human body. Technical Report AMRL-TR, 69-70. http://www.smpp.northwestern.edu/savedLiterature/ClauserEtAl.1969.pdf.

12. Hoefs, Jeremy. (n.d.). What Do Football Pads Weigh? Livestrong.com. Retrieved September 20, 2011, from http://www.livestrong.com/article/366551-what-do-football-pads-weigh/.

13. Broglio, Steven P. (2011, July). In Vivo Biomechanical measurements of a Football Player’s C6 Spine Fracture [Letter to the editor]. New England Journal of Medicine, 365(3), 279-281.

14. King, A.I., Yang, K.H., Zhang, L., and Hardy, W. ‘Is Head Injury Caused by Linear or Angular Acceleration?’ “Bertil Aldman award” Lecture, Proc. IRCOBI Conf., 2003 1-12. Retrieved from http://www.sbn-neurocirurgia.com.br/site/download/artigos/King_IRCOBI_2003.pdf