The impact of the cervical spine on concussion symptoms

Mild traumatic brain injury (MCTBI), or concussion as it is commonly known, is a major concern for health professionals working in the sporting world, and a subject that is increasingly present in the media. Several professional field hockey players such as Sydney Crosby and Éric Lindros have made headlines with concussions, and fuelled discussions with their extended withdrawal from the game over a period of several months.

The National Hockey League (NHL) is the first professional league to adopt an official policy on concussion prevention, assessment and treatment (1). During the 2011-2012 season, the NHL reported that 90 players had to miss regular-season games due to a concussion diagnosis, the majority of whom were forwards (1). Since field hockey players have a reputation for being hard on their bodies despite the pain, the true measure of concussion incidence is hard to come by. A study by Benson et al. (2011) concludes that prolonged headaches, fatigue, memory loss and abnormal neurological examinations are signs that can predict longer recovery in elite field hockey players (2). Post-concussion syndrome is diagnosed when the condition persists, i.e. when symptoms last from a few weeks to several months (3).

So what could be the causes of such chronicity?
A review of the Quebec literature published in 2016 further explains the involvement of the cervical spine in concussions (4). In field hockey, the most common concussion-inducing mechanism is contact between field hockey players, i.e. body checking (1). In this type of impact, the head usually makes a rapid acceleration and deceleration movement, called the “whiplash”, a cervical stress similar to car accidents. As a result, neck injuries and concussions are often associated, since they occur in the same process (5, 6). For the clinician, it’s difficult to clearly differentiate the origin of the symptoms, as those of concussion and neck injury are similar on many levels. A number of studies have indicated that a proportion of post-traumatic headaches and other post-concussion symptoms have musculoskeletal origins, such as in the cervical spine. The involvement of muscles, ligaments, nerves, temporomandibular joints, discs, zygapophyseal joints and the atlanto-occipital complex creates a major challenge for the clinician wishing to intervene in a patient with neck pain (7). Especially since whiplash can cause cervicogenic disorders, concussion or both, making the situation even more complex.

It is therefore very important not to neglect the impact on the cervical spine when rehabilitating after a concussion. A thorough examination of this area by a medical professional could lead to better recovery and a better understanding of the player’s progress. Other avenues, such as the involvement of the vestibular system, the oculomotor system and the proprioceptive system, should be considered and verified in the event that the field hockey player does not perform as expected.

Written by Ève Poisson, Physiotherapist and Michael Morin, Physiotherapist Rouge et Or Football

References:
1. Bonefield CM, Wecht DA, Lunsford LD (2014) Concussion in ice hockey. Progress in Neurological Surgery, 28, 161-170
2. Benson BW and al. (2011) What are the most effective risk-reduction strategies in sport concussion? British Journal of Sports Medicine, 47(5) : 321-326.
3. McCrory et al. (2013) Consensus statement on Concussion in sport – The 4th International Conference on Concussion in Sport held in Zurich, November 2012. Physical Therapy in Sport: Official Journal of the Association of Chartered Physiotherapists in Sport Medicine, 14(2) : e1-e13.
4. Morin M, Langevin P and Fait P (2016) Cervical Spine Involvement in Mild Traumatic Brain Injury – A Review. Journal of Sports Medicine, 2016, 20p.
5. Hynes LM and Dickey JP (2006) Is there a Relationship between wiplash-associated disorders and concussion in field hockey? A preliminary study. Brain Injury, 20(2) : 179-188.
6. Schneider et al (2013) The effects of rest and treatment following sport-related concussion: a systematic review of the literature. British Journal of Sports Medicine, 47(5) : 304-307.
7. Watanabe et al. (2012) Systematic review of interventions for post-traumatic headache. PM & R: The Journal of Injury, Function and Rehabilitation, 4(2): 129-140.