Cervical Artery Dysfunction

Question 1

Dittrich

Answer 1

(2007): Case-control study of 47 cases with VA or carotid dissection/stroke, compared to 47 controls with other types of strokes. Found no association between any mechanical event, including HVLAT, and cervical artery dissection.

Question 2

Thomas

Answer 2

(2011) : Medical records of 47 VBA/ICA dissection compared with 43 controls (stroke from other causes than dissection). 64% of subjects had h/o minor mechanical traums to neck within preceding 3 weeks, of which 23% had report of recent manual therapy to their neck. In contrast only 7% of controls had history of recent mechanical trauma to head/neck.
1. Minor mechanical trauma associated with CAD (23.53 odds ratio)
2. Controls had more cardiovascular risk factors (average of 3.23 more risk factors)
3. Most common symptom in VBA/ICA group was headache
4. General cardiovascular risk factors do not appear to be strongly represented in CAD

Question 3

Horner’s Syndrome?

Answer 3

Result of interruption to sympathetic nerve fibers supplying eye. The superior cervical ganglion lies in posterior wall of carotid artery.

1. Head, neck, or face pain
2. Drooping eyelid
3. Sunken eye
4. Small constricted pupil
5. Facial dryness

Question 4

Blood flow studies?

Answer 4

1. Magnetic resonance angiography is gold standard
   - all but one study demonstrated flow reduction in contralateral VA
2. Doppler (2nd best way to measure blood flow)
   - Reduced blood flow contralateral VA > ipsilateral during rotation
   - Compensatory flow demonstrated between ICA and VA, if flow decreased in one vessel will increase in other
   - Extension reduces ICA flow most but VA not affected with extension

Question 5

Recommended screen for CAD in those with neck pain and headache symptoms?

Answer 5

1. Cranial nerve and eye exam
2. BP testing
3. Signs of ICA and VA dissection (ischemic and non-ischemic)
4. PMH related to atherosclerosis
5. Doppler
6. Functional CAD positional tests (rotation for VA, extension for ICA)

Question 6

Systematic review of adverse events with cervical manip/mob?

Answer 6

Carlesso (2010). 14 RCTs and 3 observational studies. No major adverse events were reported in any of the studies (Thiel 2007 even had 50,276 cervical HVLAT’s with no adverse events). Minor adverse events (HA and increased neck pain) had average occurrence of 16.3% across all studies. No strong evidence links occurrence of adverse events to cervical treatment but may be due to small number of studies, moderate study qualities, and notable ascertainment bias.

Question 7

Summary of vascular accidents after manipulation?

Answer 7

Terrett (2001) summarized a total 265 vascular accidents, of which 142 were linked to chiros. Number of deaths following cervical HVLAT for each profression were: osteopaths =3, MD’s = 9, naturopath = 1, chiro = 17, PT’s = 0.

Question 8

Mitchell

Answer 8

(2005): VBI test is still without demonstrated validity, sensitivity, or specificity. Still no convincing evidence of method of identifying “at risk” patients.

Question 9

Asking professions about HVLAT complications/stroke?

Answer 9

1. Dvorak and Orelli (1985) - Retrospective study of 367 members of Swiss Society of Manual Medicine and asked them to recall number of manips. and complications they’d had. Estimated rate of “slight neurological complications” to be 1 in 40,000 and rate of “important complication” to be 1 in 400,000
2. Lee (1995) - Retrospective survery of California neurologists were asked to recall over previous 2 years how man “neurologic complications following chiropractic adjustment” they had encountered. 21% of neurologists reported at least one case of stroke.
3. Klougart (1996) - 10 year retrospective survery of Danish chiros to determine incidence of CVA’s. Estimated incidence of 1 case per 362 chiropractor years or 1 case per 1.3 million cervical treatment sessions.

Question 10

Vertebral artery stress in cadavers?

Answer 10

Symons (2002). Cervical spines of 5 cadavers exposed to movements similar to those that occur during cervical ROM testing and HVLAT. Cervical ROM testing caused strain 1.2% to 12.5% greater than rest. During HVLAT the average strain was 6.2% greater than at rest. Mechanical failure didn’t occur until average strains of 139% - 162% greater than rest. Strain to VA during cervical HVLAT unlikely to tear/disrupt normal VA.

Question 11

Cassidy

Answer 11

(2008): 818 VBA strokes hospitalized. In those less than 45 cases were 3 times more likely to see chiro or PCP before their stroke than controls. For 1 month preceding stroke, found an association between chiropractic care and VBA stroke, but this was stronger for PCP. For those over 45 the increased association was seen for PCP but not chiro, especially when PCP billed for neck and HA complaints. No evidence of excess risk of VBA stroke with chiropractic compared to PCP. Cervical HVLAT not ruled out as cause of VBA stroke but unlikely. These dissections are likely already in progress and simple AROM exam could cause stroke. 34% did have HTN and 34% did have heart disease.

Question 12

Murphy

Answer 12

(2010) : Two possible explanations from (Symons, Rothwell, Smith, Dittrich, Cassidy).
1. There was no way to predict, or screen for individual at risk of “post-manipulative stroke”
2. Patients with early symptoms of VADS sought care from chiro and then went on to experience a stroke, independent of cervical HVLAT.

Current evidence indicates VA dissection is not a complication of cervical manipulation; therefore, focus should shift from trying to find patient who is at risk to who is having a dissection in progress.

Question 13

Kerry and Taylor (2008)?

Answer 13

1. CAD more appropriate term than VBI
2. Thiel and Rix (2004) say that we should stop using the VBI test. There is no evidence to support construct validity of pre-manipulative vascular screening in terms of its ability to identify patients more likely to have spontaneous dissection events.
3. Upper cervical spine believed to carry greater risk because of course of VA between C2 and occiput but ICA plaques are most prevalent around bifurcation of internal/external vessels and this is usually around mid/lower cervical spine so this area can’t be considered completely safe or any less risky
4. Chiros carry our a far greater number of manipulatios than PT’s
5. Blood flow studies have demonstrated significant flow changes during passive gentle passive positioning and not fast manipulative procedures. Although quicker movement is more likely to dissect a thrombus, it is also feasible that gentler, repeated movements offer a potential dissection-inducing force.
6. Non-thrust manual therapy and other forms of hands-off PT not subject to same degree of study so judgement of their risk can’t be made.

Question 14

Smith

Answer 14

(2003): Case-control study of 51 patients with CAD and ischemic stroke or TIA (25 VA, 26 carotid). Compared them to 100 control patients suffering from other strokes, not dissections. Found no significant association between neck manipulation and ischemic stroke or TIA. However, a subgroup analysis showed the 25 VBA cases were 6x more likely to have consulted a chiropractor within 30 days of their stroke than controls.

Question 15

Kerry and Taylor (2006)?

Answer 15

Recommend 6 item screening. Headache and neck pain may be early presentation of vascular pathology, especially acute pain unlike any other. Be suspicious of vascular pathology in cases of trauma.

Question 16

Rothwell

Answer 16

(2001): Looked at Ontario health data to compare 582 cases of VBA stroke to 2328 controls with no history of stroke. For those less than 45 years, cases were 5x more likely to visit chiro within 1 week of VBA stroke.

Question 17

Systematic review of case reports: chiro/death?

Answer 17

Ernst (2010). Systematic review of case reports through 2009. 26 fatalities following chiropractic neck HVLAT were published in medical literature (many more might remain unpublished) and were reported between 1934 and 2002.

1. Ages ranged 25 y.o. male to 60 y.o. female.
2. Time between HVLAT and death was 1 hour to 58 days.
3. Of the 40 serious events mentioned, 28 could be traced back to chiros.

Question 18

Thomas (2011): VBA most common S&S’s?

Answer 18

1. HA
2. Neck pain
3. Dizziness
4. Unsteadiness

Question 19

Kerry and Taylor (2010)?

Answer 19

1. VA or ICA dissection can manifest as signs/symptoms which are non-ischemic (somatic pain), these can precede cerebral ischemia or retinal ischemia from less than a week to 30 days. Headache or neck pain may be only symptoms
2. CN palsies and Horner’s Syndrome are phenomenon indicative of ICA pathology, especially if onset is acute. Hypoglossal (12th- motor for tongue) most commonly affected, followed by glossopharyngeal, vagus, or accessory. However, all except olfactory can be affected. CN and eye exam may help identify early stages of ICA dissection. Horner’s Syndrome present in 82% of patients with ICA dissection.
3. ICA supplies the retina (via opthalmic artery) and emboli from ICA can cause retinal ischemic dysfunction (episodic loss of vision, blackout, blurring of vision)

Question 20

Thomas (2011): ICA most common S&S’s?

Answer 20

1. HA
2. Ptosis (drooping/fallen eyelid)
3. Facial palsy
4. Upper and lower limb weakness

Question 21

Kerry and Taylor (2005)?

Answer 21

VA is designed to be moved and stretched. Little evidence that negative VA test predicts anything. It is without known sensitivity or specificity.