Although chiropractic, and manipulation, have an excellent safety record, no medical procedure is completely free of potential adverse effects.

Common (1,2):

• Reactions most commonly reported are local soreness/discomfort (53%), headaches (12%), tiredness (11%), radiating discomfort (10%), dizziness, the vast majority of which resolve within 48 hours.

Rare (3,4):

• Fractures or joint injuries in isolated cases with underlying physical defects, deformities or pathologies
• Burns due to some physiotherapy procedures (heat, therapeutic ultrasound, laser, etc).
• Disc herniation.
• Cauda equina Syndrome (2) (1 case per 100 million adjustments).
• Vertebrobasilar artery (VBA) stroke (1 case per 400,000 to 1 million cervical spine manipulations).

Many patients feel immediate relief following chiropractic treatment, however the local soreness/discomfort felt after manipulation feels similar to post-exercise soreness and generally resolves within 24-48 hours.

A 2008 study in Spine has found that patients presenting with neck pain, stiffness of the neck and/or headache (all potential symptoms of a stroke in progress) had a stroke whether they saw their primary care physician or a chiropractor. The neck pain and headache symptoms are due to artery dissection. When the dissection occurs, it is only a matter or time until the patient will suffer a stroke and therefore it can happen whether they visit a chiropractor's office or their primary care physician (3).

References:

• 1. Thiel HW, Bolton JE, Docherty S, Portlock JC. Safety of chiropractic manipulation of the cervical spine: a prospective national survey. Spine. Oct 1 2007;32(21):2375-2378; discussion 2379.
• 2. Rubinstein SM, Leboeuf-Yde C, Knol DL, de Koekkoek TE, Pfeifle CE, van Tulder MW. The benefits outweigh the risks for patients undergoing chiropractic care for neck pain: a prospective, multicenter, cohort study. J Manipulative Physiol Ther. Jul-Aug 2007;30(6):408-418.
• 3. Cassidy JD, Boyle E, Cote P, et al. Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study. Spine. Feb 15 2008;33(4 Suppl):S176-183.
• 4. Boyle E, Cote P, Grier AR, Cassidy JD. Examining vertebrobasilar artery stroke in two Canadian provinces. Spine. Feb 15 2008;33(4 Suppl):S170-175.

While there are a list of orthopedic tests (Barre-Leiou Sign, Maigne's/George's and Hautant's Tests - all tests with varying degrees of full rotation, extension and lateral gaze observing for nystagmus, nausea, vertigo, syncopy, or visual disturbances) available to potentially aid in diagnosis of a stroke, evidence shows that there are no spinal orthopedic tests that can accurately (sensitively and specifically) determine if a patient is at risk for dissection (5).

Prior to the Cassidy article in Spine 2008, the performance of these tests was to aid the Chiropractor in identifying patients who may potentially suffer a VBA stroke from cervical spine manipulation. Since that time, and the lack of a causal relationship between manipulation and stroke, Chiropractors should now focus on the clinical signs and symptoms that accompany the acute onset of a stroke instead of utilizing orthopedic tests in attempt to identify potential stroke victims.

Acute Signs and Symptoms observed for include:

• Sudden numbness or weakness of the face, arms or legs
• Sudden confusion or trouble speaking or understanding others
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, or loss of balance or coordination
• Sudden severe headache with no known cause

The best indicator for the Chiropractor is the presence of the patient's "first or worse" headache, meaning a headache that is "new" to the patient and the worst headache they have experienced.

References:

• 5. Simpson R, Gemmell H. Accuracy of spinal orthopaedic tests: a systematic review. Chiro & Osteo 2006, 14:26 doi:10.1186/1746-1340-14-26