Manipulation of the cervical spine: a systematic review of case reports of serious adverse events, 1995–2001

Edzard Ernst
Med J Aust 2002; 176 (8): 376-380. || doi: 10.5694/j.1326-5377.2002.tb04459.x
Published online: 15 April 2002


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 (MEDLINEPubmed; 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.

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.


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§



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


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




32-year-old man


Dissection of right vertebral artery causing basilar artery infarction and stroke


Mild residual neurological deficit


65-year-old man with neck pain


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


48-year-old woman with neck pain


Dissection of right intracranial artery causing Wallenberg's syndrome


Persistent neurological deficit

47-year-old man

Chiropractor — CSM

Intimal tear of right vertebral artery causing transitory neurological deficits


Bypass surgery, complete recovery


59-year-old patient

Chiropractor — CSM

Emboli released from arteriosclerotic internal carotid artery causing partial loss of vision. Symptoms started during CSM


Permanent visual field defects


87-year-old man

Chiropractor — CSM

Retinal artery occlusion. CSM probably released emboli from arteriosclerotic carotid artery


No details provided


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


Gradual improvement

60-year-old man


Disc herniation at C4/C5. Symptoms developed either during or shortly after CSM


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


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


Surgery, permanent neurological deficit


33-year-old woman with neck pain

Chiropractor — CSM ("neck manipulation")

Spinal epidural haematoma. Symptoms started 15 minutes after CSM


Haematoma was surgically removed, full recovery


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


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


No details provided


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


Surgical intervention, full recovery


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


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


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


Residual neurological deficit


Young woman

Chiropractor — CSM

Infarct in left inferior cortex causing right superior homonymous quadrantanopia


Persistent abnormalities


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


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"


27-year old woman with shoulder stiffness

Chiropractor — CSM

Vertebral artery dissection causing stroke. Symptoms started after a 48-hour delay


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


34-year old woman with neck pain

Chiropractor — CSM

Vertebral artery dissection causing occipital lobe infarction and hemianopsia. Symptoms started within minutes of CSM


Persistent visual field disturbances


31-year old woman

Chiropractor — CSM ("rapid rotary manipulation")

Left vertebral artery dissection causing cerebellar infarction


No details provided

64-year-old man

Chiropractor — CSM

Dissection of left internal carotid artery causing parietal stroke


No details provided

51-year-old man


Right internal carotid artery dissection causing subcortical stroke


No details provided


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


Surgical obliteration of fistula, rapid improvement


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




34-year-old man with whiplash injury, non-radiating neck pain

Chiropractor — CSM

Dural tear causing persistent positional dizziness

No details provided

Full recovery


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


No details provided


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


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


No details provided


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-year-old woman with chronic headache

Chiropractor — CSM

Left vertebral artery dissection causing left pontine infarct and stroke. Symptoms developed during CSM


Permanent severe neurological deficit




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


Prolapse of disc at level C5/C6. Report describes one further case of myelopathy


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


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

§ Tests that established diagnosis. CT = computed tomography. EMG = electromyography. MRI = magnetic resonance imaging. CSM = cervical spine manipulation.

Received 9 August 2001, accepted 3 January 2002

  • Edzard Ernst

  • Department of Complementary Medicine, School of Sport and Health Sciences, University of Exeter, Exeter, UK.


Competing interests:

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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