Spinal manipulation is a popular form of treatment used by chiropractors, osteopaths, doctors, physiotherapists and other healthcare professionals to treat a range of (mostly) musculoskeletal problems. The American Chiropractic Association1 defines spinal manipulation as a passive manual manoeuvre "during which the three-joint complex is carried beyond the normal physiological range of movement without exceeding the boundaries of anatomical integrity". The essential characteristic is a low- or high-velocity thrust — brief, sudden, and carefully administered at the end of the normal passive range of movement — in an attempt to increase the joint's range of movement. This distinguishes manipulation from other forms of manual therapy.
The one-year prevalence figures of spinal manipulation in representative samples of general populations are high: 15% (1996, Australia), 10% (1988, Austria), 33% (1996, UK), 7% (1997, USA), and 16% (1998, USA).2 Several articles3,4 published before the mid-1990s described the potential risks of spinal manipulation, and showed that, in particular, manipulation of the cervical spine is associated with serious risks. This systematic review of case reports published between 1995 and 2001 evaluates the reported evidence of serious adverse events after cervical spine manipulation.
Computerised literature searches were performed using MEDLINE (via Pubmed); EMBASE; the Cochrane Library; AMED (Allied and Complementary Medicine Database); and CISCOM (Centralised Information Service for Complementary Medicine) (January 1995 – September 2001). The search terms used were "adverse effects", "adverse events", "chiropractic", "complications", "manual therapy", "osteopathy", "risk", "safety", "spinal manipulation", "strokes", "vascular accidents". In addition, I searched my own files and consulted nine other experts. The bibliographies of all located articles were also searched.
All case reports containing original data relating to serious adverse events associated with cervical spine manipulation were included. No language restrictions were applied.
The 31 case reports (42 individual cases)5-35 that met the inclusion criteria are summarised in the Box. Most reports were from the United States, but the spread across countries is wide. The reports were published fairly evenly over the time period, with a greater number in 1996 and 2001. The patients were equally distributed between the sexes (21 male, 20 female, one unknown) and middle-aged (range, 3 months to 87 years). Most were treated by chiropractors (n = 30). The exact nature of the cervical spine manipulation was frequently not described in detail; when it was, rotation and tilting of the head were often involved. Arterial dissection, usually of the vertebral arteries, causing stroke was the most common serious adverse event (at least 18 cases). In most instances, the acute onset of symptoms after the manipulation made a causal relationship likely. Symptoms often developed quickly — after or during therapy — and varied widely according to the exact nature of the injury. The eventual outcome was often not reported, but included serious sequelae, such as permanent visual field loss, permanent neurological deficit and death (serious sequelae in at least 17 cases) (see Box).
Cervical spine manipulation continues to be associated with vascular, neurological and other serious complications. In particular, high velocity thrusts of the cervical spine, especially with rotational movement, seem to result in complications.3,4 The force and extent of these movements can cause arterial dissection, particularly of the vertebral arteries, in predisposed individuals. In isolated cases, forceful massage alone can lead to serious problems.35 No particular risk factors for such events, or adequate, practical means of prevention, have yet been convincingly demonstrated. Some authors simply recommend not referring patients to practitioners practising rotary cervical manipulation.3,4
The obvious and important limitations of the data must be acknowledged. On the one hand, case reports and case series are by definition anecdotal (Level IV evidence, according to the National Health and Medical Research Council system for assessing level of evidence),36 and thus are rarely conclusive. In many instances, not all details of the case were reported (eg, the exact nature of the interventions and a causal relationship between the intervention and the clinical event was not always established.
On the other hand, under-reporting is likely to significantly distort the evidence. A recent survey of neurologists found 35 cases of neurological complications occurring within 24 hours of cervical spine manipulation,34 none of which had been published. Robertson took an audience poll at a meeting of the Stroke Council of the American Heart Association, which disclosed 360 unreported cases of stroke after spinal manipulations.37 De Bray and colleagues estimated that 12% of all vertebrobasilar artery dissections follow cervical spine manipulations.38
In view of this, all existing estimates of risk must be seen as not sufficiently reliable for responsible decision-making, and information about these risks should be included when informed consent is obtained.39 This is supported by several investigators.23,40 Recent survey data41 suggest that Australian chiropractors rarely obtain verbal consent, and never written consent, from their patients. They also seldom discuss the potential risks of chiropractic adjustments, and may therefore not meet all the legal requirements for informed consent.41
How can the risk of adverse events associated with cervical spine manipulation be minimised in future? Clinical competence in those performing spinal manipulation seems an essential and obvious precondition. Contraindications must be strictly observed. Vautravers argued that even minor unwanted effects should be considered as an absolute contraindication for future spinal manipulations.40 About 50% of all chiropractic patients experience such minor adverse effects.42
In conclusion, serious complications of cervical spine manipulation appear to occur regularly. Their incidence is essentially unknown and should be established as a matter of urgency through adequately designed investigations.
Summary of case reports of adverse events after cervical spine manipulation
Ref no. |
Patient and indication (if provided) |
Type of therapist (if provided) and intervention |
Adverse event |
Diagnosed by§ |
Outcome |
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5 |
36-year-old man with low back pain |
Chiropractor — all spinal regions manipulated, including the cervical spine, with forceful rotation of flexed head |
Symptoms developed "within hours" of CSM. Long thoracic nerve palsy with motor axon degeneration causing paraesthesiae, pain and reduced mobility of right arm |
Nerve conduction studies, EMG, MRI |
No details provided |
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6 |
29-year-old woman with neck pain, vertigo |
Chiropractor — CSM with tilting and rotation of head |
Dissection of internal carotid artery causing stroke with somnolence. Acute dissection confirmed by autopsy |
CT |
Death |
||||||||||
7 |
32-year-old man |
CSM |
Dissection of right vertebral artery causing basilar artery infarction and stroke |
CT, MRI |
Mild residual neurological deficit |
||||||||||
8 |
65-year-old man with neck pain |
CSM |
Diaphragmatic palsy (patient remained symptom-free) — a chance finding on routine x-ray |
Chest X-ray, fluoroscopy |
Not applicable |
||||||||||
49-year-old woman with arthritic pain |
Chiropractor — CSM |
Diaphragmatic palsy causing chronic dyspnoea. Symptoms developed over several months of regular CSM — all other causes were excluded |
Chest X-ray, fluoroscopy, lung function tests |
No details provided |
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9 |
48-year-old woman with neck pain |
CSM |
Dissection of right intracranial artery causing Wallenberg's syndrome |
MRI |
Persistent neurological deficit |
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47-year-old man |
Chiropractor — CSM |
Intimal tear of right vertebral artery causing transitory neurological deficits |
Arteriogram |
Bypass surgery, complete recovery |
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10 |
59-year-old patient |
Chiropractor — CSM |
Emboli released from arteriosclerotic internal carotid artery causing partial loss of vision. Symptoms started during CSM |
Ophthalmoscopy |
Permanent visual field defects |
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11 |
87-year-old man |
Chiropractor — CSM |
Retinal artery occlusion. CSM probably released emboli from arteriosclerotic carotid artery |
MRI |
No details provided |
||||||||||
12 |
67-year-old man with neck pain |
Chiropractor — CSM |
Prolapse of discs C5/C6 and C6/C7 causing radiculopathy. Symptoms developed either during or shortly after CSM |
MRI, EMG |
Gradual improvement |
||||||||||
60-year-old man |
CSM |
Disc herniation at C4/C5. Symptoms developed either during or shortly after CSM |
CT |
Full recovery |
|||||||||||
56-year-old man with neck pain |
Chiropractor — CSM |
Protrusion of discs C4/C5, C5/C6 and C6/C7 causing cervical myelopathy. Symptoms developed either during or shortly after CSM |
MRI |
Surgery, gait remained ataxic |
|||||||||||
62-year-old man with neck pain |
Chiropractor — CSM |
Stenoses of spinal canal at C3, C5/C6, C7 causing cervical myelopathy. Symptoms developed either during or shortly after CSM |
MRI |
Surgery, permanent neurological deficit |
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13 |
33-year-old woman with neck pain |
Chiropractor — CSM ("neck manipulation") |
Spinal epidural haematoma. Symptoms started 15 minutes after CSM |
CT, MRI |
Haematoma was surgically removed, full recovery |
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14 |
39-year-old woman |
Chiropractor — CSM |
Ischaemic lesion in medulla oblongata causing stroke. Symptoms developed 5 hours after CSM |
MRI, cerebral angiography |
No details provided |
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15 |
39-year-old woman with neck and shoulder pain |
Chiropractor — CSM |
Acute infarction of the ventromedial aspect of the inferior right occipital lobe causing stroke with left peripheral visual field loss. Symptoms started immediately after CSM |
MRI |
No details provided |
||||||||||
16 |
45-year-old woman with tension headache |
Chiropractor — CSM with high velocity rotational thrust |
Dissection of carotid artery causing complete ophthalmoplegia. Unusual case of previously asymptomatic posterior communicating artery aneurysm |
CT, MRI |
Surgical intervention, full recovery |
||||||||||
17 |
36-year-old man with neck and shoulder pain |
Chiropractor — CSM |
Vertebral artery dissection causing stroke. Symptoms started 30 min after CSM |
MRI, angiography |
Good clinical improvement and resolution of dissection |
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18 |
38-year-old woman with neck pain |
Chiropractor — CSM with sudden lateral flexion |
Cervical injury causing profuse vomiting, vertigo and Horner's syndrome. Symptoms started 30 min after CSM |
MRI, angiography |
No details provided |
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19 |
58-year-old woman with neck pain |
Chiropractor — CSM with high velocity thrust |
Contusion of upper spinal cord causing Brown–Séquard syndrome. Symptoms started immediately after therapy |
MRI |
Residual neurological deficit |
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20 |
Young woman |
Chiropractor — CSM |
Infarct in left inferior cortex causing right superior homonymous quadrantanopia |
MRI |
Persistent abnormalities |
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21 |
34-year-old woman with neck pain |
Chiropractor — CSM |
Dissection of both vertebral arteries causing cerebellar infarction and stroke. Symptoms developed hours after therapy |
MRI, duplex sonography |
Residual neurological deficit |
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22 |
50-year-old woman with neck pain |
Chiropractor — CSM including rotation and tilting of head |
Left intracranial vertebral artery and carotid artery dissection causing stroke. Symptoms started "a few minutes" after CSM |
MRI, doppler sonography |
"Gradual improvement" |
||||||||||
23 |
27-year old woman with shoulder stiffness |
Chiropractor — CSM |
Vertebral artery dissection causing stroke. Symptoms started after a 48-hour delay |
MRI, CT |
Minimal persistent neurological deficit |
||||||||||
37-year old man with headache |
Chiropractor — CSM |
Vertebral artery dissection causing multiple infarcts. Symptoms started immediately after CSM |
MRI, CT, angiography |
Persistent diplopia and ataxia |
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24 |
34-year old woman with neck pain |
Chiropractor — CSM |
Vertebral artery dissection causing occipital lobe infarction and hemianopsia. Symptoms started within minutes of CSM |
MRI |
Persistent visual field disturbances |
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25 |
31-year old woman |
Chiropractor — CSM ("rapid rotary manipulation") |
Left vertebral artery dissection causing cerebellar infarction |
MRI |
No details provided |
||||||||||
64-year-old man |
Chiropractor — CSM |
Dissection of left internal carotid artery causing parietal stroke |
MRI |
No details provided |
|||||||||||
51-year-old man |
CSM |
Right internal carotid artery dissection causing subcortical stroke |
MRI |
No details provided |
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26 |
57-year-old man |
Chiropractor — CSM |
Vertebral arteriovenous fistula at C1 level causing radiculopathy of right arm. Vertebral artery dissection due to CSM the most likely cause |
Angiography |
Surgical obliteration of fistula, rapid improvement |
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27 |
3-month-old baby girl |
Physiotherapist — forced active rotation and retraction of head |
Bleeding into adventitia of both vertebral arteries causing ischaemia of caudal brainstem with subarachnoid haemorrhage |
MRI |
Death |
||||||||||
28 |
34-year-old man with whiplash injury, non-radiating neck pain |
Chiropractor — CSM |
Dural tear causing persistent positional dizziness |
No details provided |
Full recovery |
||||||||||
29 |
43-year-old man with tinnitus |
Orthopaedic surgeon — CSM |
Intracapsular/intraosseous oedema of the facet joints C2/C3, with lesions of the nerve root at C3 causing severe neck pain |
CT |
No details provided |
||||||||||
30 |
30-year-old man (no indication) |
"Untrained person" (barber) — CSM ("jerked his neck to the extreme right") |
Extramedullary, intradural mass compressing spinal cord at C1/C2. Onset of symptoms immediately after CSM |
Plain x-ray, MRI |
Permanent neurological deficit |
||||||||||
31 |
44-year-old man with a strained shoulder muscle |
Chiropractor — CSM |
Dissection of right internal carotid artery causing Horner's syndrome. There was also a subtle dissection of the right vertebral artery |
MRI |
No details provided |
||||||||||
32 |
47-year-old man with stiffness of neck and shoulder |
Chiropractor — CSM including neck rotation |
Phrenic nerve injury causing diaphragmatic paralysis. Symptoms (severe dyspnoea) started after several hours delay |
X-rays, fluoro-scopy, lung function tests |
Residual deficit, breathing difficulties |
||||||||||
33 |
33-year-old woman with chronic headache |
Chiropractor — CSM |
Left vertebral artery dissection causing left pontine infarct and stroke. Symptoms developed during CSM |
CT, MRI |
Permanent severe neurological deficit |
||||||||||
34 |
Woman |
CSM |
Vertebral artery dissection causing occlusion and stroke with cerebral oedema. Symptoms developed within 4 hours of CSM. Eight further cases of stroke described |
CT, angiogram |
Surgical decompression, removal of part of cerebellum, permanent neurological deficit |
||||||||||
46-year-old man |
Chiropractor — CSM |
Subdural haematoma. Symptoms developed immediately after CSM |
No details provided |
Surgical intervention, full recovery |
|||||||||||
42-year-old woman |
CSM |
Prolapse of disc at level C5/C6. Report describes one further case of myelopathy |
MRI |
Major residual deficits |
|||||||||||
32-year-old woman |
Osteopath — CSM |
Radiculopathy at level C6/C7/C8. Symptoms began within 12 hours of CSM |
No details provided |
Minor residual deficit |
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35 |
80-year-old man with neck and shoulder stiffness |
Shiatsu practitioner — shiatsu massage of upper neck |
Retinal artery embolism causing partial loss of vision. Treatment mainly forceful neck massage (it is arguable whether this constitutes CSM) |
MRI, angiography |
Permanent ocular effects |
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§ Tests that established diagnosis. CT = computed tomography. EMG = electromyography. MRI = magnetic resonance imaging. CSM = cervical spine manipulation. |
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Received 9 August 2001, accepted 3 January 2002
- Edzard Ernst1
- Department of Complementary Medicine, School of Sport and Health Sciences, University of Exeter, Exeter, UK.
I have received training in spinal manipulation and have applied it clinically, but have no financial competing interests related to spinal manipulation.
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Abstract
Objective: To summarise recent evidence from case reports (published January 1995 – September 2001) of adverse events after cervical spine manipulation.
Data sources: Five computerised literature searches (MEDLINE – Pubmed; EMBASE, the Cochrane Library, AMED [Allied and Complementary Medicine Database], and CISCOM [Centralised Information Service for Complementary Medicine]) were performed. No language restrictions were applied.
Study selection: All case reports containing original data of adverse events after cervical spine manipulation were included.
Data extraction: All articles were evaluated and key data extracted according to pre-defined criteria: patient's age, sex and diagnosis; type of therapist; type of treatment; nature of adverse event; method of diagnosis; and clinical outcome.
Data synthesis: Thirty-one case reports (42 individual cases) were found. The patients were equally distributed between the sexes (21 male, 20 female, one unknown) and mostly middle-aged (range, 3 months to 87 years). Most were treated by chiropractors. Arterial dissection causing stroke was reported in at least 18 cases.
Conclusions: Serious adverse events after cervical spine manipulation continue to be reported. As the incidence of these events is unknown, large and rigorous prospective studies of cervical spine manipulation are needed to accurately define the risks.