Cervical Spinal Anatomy and Stroke
The anatomy of the neck means that the carotid artery and vertebral arteries are packed in along with other structures and liable to be damaged in cases of acute neck trauma. People may also have weak arterial walls and/or clogged arteries that can be the cause of neck pain and which are liable to rupture or tear and lead to arterial bleeds, blood clots, and strokes. In cases of weak arterial walls, or abnormalities in the neck anatomy, chiropractic manipulation in the cervical spine could lead to acute arterial dissection and stroke with some reports in the literature of such events.
Neck Pain and Arterial Dissection – Which Comes First?
The problem with such reports of cervical spine adjustment causing arterial dissection and stroke is that patients may have sought out their chiropractor to treat neck pain without realizing that the neck pain is actually caused by arterial dissection. Neck pain is a key symptom of arterial dissection but the many common causes of neck pain mean that it is rarely thought of as an initial diagnosis. Determining whether arterial dissection is caused by chiropractic manipulation or whether the dissection was the initial cause of neck pain prompting the chiro visit is almost impossible after the fact, but it may be that chiropractic treatment of the cervical spine exacerbates the arterial damage and increases the risk for stroke.
Evidence Connecting Chiropractic with Stroke
In other cases it may be that a regular visit to the chiropractor for an unrelated issue actually leads to acute neck pain and a stroke shortly after, or even in the days following. In such cases it is likely that the cervical spine manipulation is the culprit and that chiropractic adjustment did lead to arterial dissection and stroke. The only way to prove such a relationship is through large trials assessing a high volume of patient information, which are unlikely to take place due to funding constraints and the difficulties of conducting such research.
Permanent Disability After Chiropractic
Alberquerque, et al (2011), reported on thirteen patients undergoing chiropractic manipulation and then developing symptoms including neurological deficits, head and neck pain, or both within hours or days of their chiropractic treatment. These patients had arterial dissections along the vertebral artery, and internal carotid artery, including the cervical ICA and the petrocavernous ICA, as well as the basilar artery. Treatment for the arterial dissections involved stenting and thrombolysis with three patients needing emergency cerebellar decompression to avoid impending herniation. Not all patients required neck surgery, however, with medications given to prevent clotting and stroke in six of the thirteen.
Follow-up of these patients revealed permanent neurological deficits in three and one death from a cerebellar stroke. The other nine patients had a complete recovery but the cases demonstrate how cervical spinal manipulation may have serious consequences requiring neck surgery, cranial surgery, and leading to permanent disability or death.
EDS, Arterial Dissection, and Neck Pain
Rather worryingly, some emerging risk factors for cervical artery dissection include respiratory tract infections (which can cause acute neck trauma through coughing), as well as migraine, and Ehlers Danlos-Syndrome IV (Micheli, et al, 2010). These conditions may also cause neck pain or be attributed to a problem in the cervical spine, causing patients to seek chiropractic help and, ironically, creating the potential for increased risk of arterial dissection upon chiropractic manipulation. Cervical artery dissection (CAD) is the most common cause of ischemic stroke in young adults and the rising popularity of chiropractic treatment could mean that many more patients with suspected fibromyalgia, EDS, migraine syndromes, and chronic neck pain are at risk of permanent disability after chiropractic treatment.
Risks of Chiropractic
Other reviews of neck adjustments and adverse events have noted that arterial dissection is not the only potential risk of chiropractic treatment. Myelopathy, vertebral disc extrusion, and epidural haematoma are also found in association with chiropractic adjustment in the literature, with one review putting the frequency of adverse events as between 33% and 60.9% and the incidence of strokes at 5/100,000 manipulations and deaths at 2.69 per 10 million manipulations. These figures are courtesy of Gouveia, et al (2009) who looked at 376 research papers on chiropractic treatment. Unfortunately, they had to discard almost all of these and were left with just 46 studies with sufficient detail about adverse events associated with chiropractic treatment.
Reducing Neck Pain Risks
Patients with a personal history, or family history, of arterial problems and cervical dissections, as well as an increased risk of stroke are probably well advised to avoid chiropractic neck adjustments as well as any other potential causes of acute neck trauma. This includes things such as rollercoasters, skydiving, acrobatics, and bungee-jumping, as well as ensuring that they have a good driving set-up to minimize the impact of whiplash should they get in an accident. Whilst the risks of arterial dissection and stroke are likely to be increased by chiropractic manipulation this does not mean that all such treatment should be ceased. Chiropractic treatment for neck pain and a variety of other conditions helps many patients have improved quality of life. Certainly, more research needs doing to uncover the connection between chiropractic, arterial dissection, and stroke, and patients with those risk factors mentioned may wish to use alternative neck pain treatments in the meantime.
Ernst E. Deaths after chiropractic: a review of published cases. Int J Clin Pract. 2010;64:1162-1165.
Chen WL, Chern CH, Wu YL, Lee CH., Vertebral artery dissection and cerebellar infarction following chiropractic manipulation. Emerg Med J. 2006 Jan;23(1):e1.
Micheli S, Paciaroni M, Corea F, Agnelli G, Zampolini M, Caso V., Cervical artery dissection: emerging risk factors. Open Neurol J. 2010 Jun 15;4:50-5.
Gouveia LO, Castanho P, Ferreira JJ., Safety of chiropractic interventions: a systematic review. Spine (Phila Pa 1976). 2009 May 15;34(11):E405-13.
Albuquerque FC, Hu YC, Dashti SR, Abla AA, Clark JC, Alkire B, Theodore N, McDougall CG., Craniocervical arterial dissections as sequelae of chiropractic manipulation: patterns of injury and management. J Neurosurg. 2011 Dec;115(6):1197-205. Epub 2011 Sep 16.