Chiropractic care – The “Adjustment”

 In 2012, I graduated from the University of Windsor and began my studies at the Canadian Memorial Chiropractic College. As I now prepare to walk across the stage this summer, my family and friends still ask me “how is physio school going?” “Can you massage my feet for me?” “It took you eight years to become a chiro?!” At first, it broke my heart to hear that so many people (especially my friends and family) we ignorant to chiropractic. On top of that, it has been astonishing to hear such questions as “are chiropractic adjustments dangerous?” or, “is it true that chiropractic adjustments of the neck can cause stroke?” Before I go any further, lets clear this up.

The risk of suffering a stroke after a neck adjustment is reported to be less than 1 in 3 million. To put this into perspective, the odds of being struck by lightning in Canada are 1 in about 960,000. You’re greater than three times more likely to be struck by lightening than suffer a stroke after a visit to your chiropractor! The theory is that an adjustment of the neck may cause a dissection of the vertebral artery. Dissection (or tearing) of this artery may compromise blood flow to the brain, causing stroke. Research has show that more stress is placed on the vertebral artery when you check you’re blind spot while driving. Would you refrain from checking you’re blind spot while driving in fear of suffering a stroke? I guess that’s up to you.

Right Vertebral Artery

The stroke statistic is only based on a temporal relationship; patients who suffered a stroke reported receiving spinal manipulation as far as 2 weeks before the stroke was detected. This is a typical case of being at the wrong place at the wrong time. To date, there have been no studies showing that spinal manipulations (ie. adjustments) CAUSE a stroke. Statistics show that you are more likely to suffer a stroke after visiting your medical doctor! Once again, this is a temporal relationship.  During the initial stages of a stroke, symptoms may mimic musculoskeletal problems, such as neck pain, headaches, dizziness, blurry vision and so on. When these patients visit their health care professionals, or in this case their chiropractors, a stroke may already be in progress, but they are not aware of it.  If a proper and through examination of the patient is not completed, a stroke may go undetected until the condition has progressed significantly, after a visit with their health practitioner. Similar statistics are seen with low back adjustments and disc herniation.

Let’s get back on track now. What is Chiropractic? As described by the Ontario Chiropractic Association (OCA):

“Chiropractic is one of the largest primary health care professions in Ontario. It is a non-invasive, hands-on health care discipline that focuses on the musculoskeletal system. Chiropractors practice with a manual approach, providing diagnosis, treatment and preventive care for disorders related to the spine, pelvis, nervous system and joints. Chiropractors use a combination of treatments, all of which are predicated on the specific needs of the patients. After taking a complete history and diagnosing a patient, a chiropractor can help develop and carry out a comprehensive treatment/management plan, recommend therapeutic exercise and other non-invasive therapies, and provide nutritional, dietary and lifestyle counselling.”

Chiropractors manage physical conditions involving the nervous system and musculoskeletal system. A common question I hear is “what is the difference between a chiropractor and a physiotherapist?” There are many similarities in the scopes of practice of these two health professions. The main thing that I believe sets us apart from other manual therapists is our expertise in administering spinal manipulative therapy (SMT), aka “the adjustment”. SMT can be described as taking a joint to its passive end-range, then applying a high-velocity low-amplitude thrust to take that joint to its paraphysiological space. This space is found just past the passive end-range of a joint, without causing tissue damage. When this space is reached with SMT, an audible “pop” or “crack” can be heard, which is termed a “cavitation”. There is some controversy with the cause of the cavitation.  Previous theories suggested the cavitation to be the popping of gaseous bubbles. Most recent research has used MRI for real-time visualization of joint cavitation in knuckles. This study has shown joint cavitation to be due to tribonucleation: the rapid separation of surfaces (in this instance the articulating surfaces of two bones) with subsequent cavity (space) formation (Kawchuk, et al. 2015). If you are interested in seeing what cracking you’re knuckles looks like with MRI, check out the YouTube link below:

SMT can be applied to any synovial joint in the body. A synovial joint is when two bones meet and are connected by a fibrous joint capsule. Within this capsule, the joint cavity is filled with synovial fluid, which acts to reduce friction between the articulating bone surfaces. For numerous reasons, a joint can become restricted. Inadequate movement and reduced joint space can lead to degeneration of the cartilage and pain of the joint. This is commonly referred to as “arthritis” (joint inflammation) or “arthralgia” (joint pain). SMT can be used in both acute and chronic joint issues to improve joint function and joint health. Aside from its local effects on the joint, SMT has also been shown to act as an analgesic, improve neurological function, improve muscle function and influence hormonal levels. When a joint is moved within its passive-end range, it is referred to as a joint “mobilization”.

As chiropractors, SMT is our bread and butter. It is what sets us apart from other manual therapy disciplines. Students at CMCC participate in over 4,200 hours of academic and clinical education, which is comparable to, if not more than, most medical doctor programs. In the first three years, 336 hours are devoted to the hand-on practice of assessments and treatments, including the SMT. The 4th year involves a 12-month internship of providing chiropractic care under the license and supervision of an experience chiropractor. This internship includes 1000 hours of working in a clinic with a minimum of 250 SMT’s provided during a minimum of 380 patient treatments. No other health profession receives this much training and practice in the application of SMT.

Although joint manipulation can be applied to many joints in the body, there are 3 particular cases that I wanted to highlight: low back pain, neck pain and headaches.

Low back pain (LBP) is very common. Up to 84% of adults have low back pain at some point in their lives, and greater than 25% report low back pain in the last 3 months. In the US, health care expenditure for low back pain in 1998 was estimated at $90 billion. Since then, costs of low back care have risen. Low back pain is one of the most common reasons for missed work or reduced productivity while at work, resulting in high indirect costs.  LBP can be classified as acute (lasting <6 weeks), subacute (lasting 6-12 weeks) and chronic (lasting >12 weeks). Some key studies on low back pain and spinal manipulation (AHRQ, 2016) are highlighted below.
·       Acute LBP
o   2 trials found SMT to be associated with better effects on function versus sham SMT. Effects on pain favoured manipulation, but this finding was not statistically significant.
o   1 trial found patients with acute or subacute LBP found SMT associated with moderate effects vs. usual care on pain and small effect on function at short-term follow-up.
o   4 trials found SMT plus either exercise or advice associated with greater improvement in function at 1 week versus exercise or advice alone (no difference at 1 month or 3 months).
·       Chronic LBP
o   1 high quality trial found SMT associated with greater improvement in the “main complaint” vs. an inert treatment.
o   A systematic review found SMT associated with better short-term relief vs. other active interventions at 1 month and 6 months. SMT was also associated with greater improvement in function versus other active interventions at 1 month.
o   A systematic review found spinal manipulation plus another active treatment associated with greater pain relief at 1 month, 3 months and 12 months versus other treatment alone. This combination therapy was also associated with better function at 1 month, 3 months and 12 months.
·       Radicular low back pain (example, sciatica)
o   1 good-quality trial found SMT plus home exercise and advice associated with greater improvement in leg and back pain in 12 weeks versus home exercise and advice alone.
·       No serious adverse events were reported and most adverse events were related to muscle soreness or transient increase in pain.

Neck Pain, as described by the Ontario chiropractic association (OCA), can be broken down into non-specific (not due to whiplash) and whiplash-associated.
·       Non-specific à The annual prevalence of non-specific neck pain (aka “mechanical neck pain”) is estimated to range between 30-50%. Persistent or recurrent neck pain is reported by 50-85% of patients 1-5 years after initial onset. Its course is usually episodic and complete recovery is uncommon for most patients. 27% of patients seeking chiropractic treatment report neck problems.
o   Acute
§  SMT is recommended for the treatment of acute neck pain for both short- and long-term benefit (days to recovery, pain) when used in combination with other treatment modalities (advice, exercise, and mobilization).
§  Mobilization is recommended for the treatment of acute neck pain for short-term (up to 12 weeks) and long-term benefit (days to recovery, pain) in combination with advice and exercise.
§  Home exercise with advice or training is recommended in the treatment of acute neck pain for both short and long-term benefits (neck pain)
o   Chronic
§  SMT is recommended in the treatment of chronic neck pain for short and long-term benefit (pain, disability)
§  SMT is recommended in the treatment of chronic neck pain as part of a multimodal approach for both short- and long-term benefit (pain, disability, neck range of motion).
§  Mobilization is recommended for the treatment of chronic neck pain for short-term (immediate) benefit (pain, neck range of motion)
§  Manual therapy is recommended in the treatment of chronic neck pain for the short and long-term benefit (pain, disability, neck range of motion, strength) in combination with advice, stretching and exercise.
·       Whiplash-associated disorders (WAD) à WAD of the neck is further divided into 4 categories (WAD 1 to 4). 90% of WAD cases are diagnosed as type 2 – a whiplash injury with neck symptoms (pain and stiffness), musculoskeletal signs and substantial interference with activities of daily living (ex. Point tenderness, decreased neck range of motion). Recommendations for SMT vary, depending on the time frame since injury.
o   Very low-frequency of SMT is recommended in the initial 7 days post-injury
o   High frequency of SMT is recommended from 1 to 12 weeks post-injury
o   Low to medium frequency of SMT is recommended greater than 12 weeks post-injury.

Headaches, based on patient history and physical examination, can be further classified into 3 types: migraine, tension-type and cervicogenic.
·       Migraine
o   SMT is recommended for the management of episodic or chronic migraine (with or without aura)
o   Multimodal multidisciplinary care (exercise, relaxation, stress and nutritional counseling, massage therapy) is recommended for the management of episodic or chronic migraine
·       Tension type
o   Low-load craniocervical mobilization is recommended for longer term (ex. 6 months) management of patients with episodic or chronic tension-type headaches
o   SMT cannot be recommended for episodic tension-type headaches, and a recommendation cannot be made for or against the use of SMT for chronic tension-type headaches.
·       Cervicogenic
o   SMT is recommended for the management of cervicogenic headache.
o   Joint mobilization is recommended for cervicogenic headache.
o   Deep neck flexor exercises are recommended for cervicogenic headache.

Low back pain, neck pain and headaches are the most common conditions treated by chiropractors. However, there is much more chiropractors can help with, including, but not limited to:
·       Strains and Sprains
·       Repetitive strain injuries
·       Work and sports injuries
·       Arthritis
·       Limited range of motion in joints
·       General health and well-being

For more information on what a chiropractor can do for you, you can visit the Ontario Chiropractic Association website, ask your Catalyst chiropractor or ask myself. Stay active and stay healthy!

Mitch Broser
Strength & Conditioning Specialist


1.     Cassidy JD, et al. risk of vertebrobasilar stroke and chiropractic care. Spine. 2008. 33:4S; S176-S183.

2.     Kawchuk GN, Fryer J, Jaremko JL, Zeng H, Rowe L, Thompson R (2015) Real-Time Visualization of Joint Cavitation. PLoS ONE 10(4): e0119470. doi:10.1371/journal.pone.0119470

3.     Effective health care program. Noninvasive treatments for low back pain. Comparative effectiveness review, number 169. Agency for healthcare research and quality, 2016.

4.     Clinical practice guideline for the chiropractic treatment of adults with neck pain. 2014. (available at:

5.     Practice guide for the management of whiplash-associated disorders in adults. 2010. (available at


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