LETTER TO THE EDITOR: WILDER J, DEMETRIOUS J, CONWAY P ET AL. INFORMED CONSENT IN CHIROPRACTIC: COMMENTARY OFNBROWN AND LEHMAN’S “INFORMED CONSENT REGARDING RISK OF STROKE FROM CERVICAL SPINE MANIPULATION.” J CONTEMPORARY CHIROPRACTIC 2025;8(1)

To the Editor

We read with interest the August 2025 commentary in the Journal of Contemporary Chiropractic by Wilder et al. entitled, Informed Consent in Chiropractic: Commentary on Brown & Lehman’s “Informed Consent Regarding Risk of Stroke from Cervical Spine Manipulation.”¹ The authors were responding to our 2025 narrative review in the Journal of the International Academy of Neuromusculoskeletal Medicine.²

Wilder et al. argue that informed consent to the risk of stroke from cervical spine manipulation (CSM) is not indicated because there is no evidence that CSM can dislodge a thrombus from an existing cervical artery dissection (CAD) and cause immediate thromboembolic stroke.

Wilder et al. argue that because there is no evidence that CSM can cause CAD,³ there is also no evidence that CAD can cause stroke. We agree there is no convincing evidence that CSM can cause CAD in normal cervical arteries.³ However, CAD and stroke are separate medical conditions. CAD is a tear in the inner lining of a cervical artery.^4–6 Ischemic stroke is a loss of blood supply to the brain.⁷ While CAD can cause stroke, CAD is not a stroke. Only 2% of all strokes are estimated to be caused by CAD.⁵ The majority of CADs will not progress to stroke with medical treatment,⁸ and CADs may heal and become asymptomatic without any treatment.^8,9

There is support in the literature that sudden neck movement from CSM can dislodge a loosely adherent thrombus from an existing CAD and cause immediate thromboembolic stroke.¹⁰ This support comes from 18 studies consisting of 1 case report,¹¹ 6 case serie,^12–17 6 review studies,^18–23 1 biomechanical study,²⁴ 3 epidemiological studie^25–27 and 1 systematic review.²⁸ These studies come from researchers in chiropractic, medicine, physical therapy, osteopathy, and biomechanics. Epidemiological studies conclude the risk of stroke following CSM is low but not zero.^25,26,29,30

Due to the life-threatening nature of stroke, randomized controlled trials (RCTs) to establish causation are unethical.³¹ In the absence of RCTs, probabilistic reasoning and inference using the best available evidence to assess risk must be relied on.³²

Chiropractors should adhere to the standard of care by employing evidence-based risk assessment strategies to exclude CAD prior to performing CSM.^4,33–35 Implementing thorough clinical evaluations, including patient history, physical examination, and, when indicated, advanced imaging (CTA, MRA), can mitigate the risk of stroke and enhance patient safety. By acknowledging this risk and prioritizing informed consent, the chiropractic profession can uphold its commitment to patient-centered, evidence-based care.^2,36,37

Steven Brown, DC, DIAMA
James Lehman, DC, MBA, DIANM

In Response

We appreciate the opportunity to respond to Brown and Lehman (JCC, October 2025), who once again advance the hypothesis that cervical spine manipulation (CSM) can dislodge a thrombus from a pre-existing cervical arterial dissection (CAD) and precipitate ischemic stroke. This hypothesis remains unsubstantiated by empirical, biomechanical, and epidemiologic evidence.

Brown and Lehman’s reliance on low-level evidence consisting of anecdotal, case-based, or temporal associations, to the exclusion of existing higher-quality evidence, suggests selective author bias. Their interpretation of the current research literature results in erroneous opinions and determinations.

Multiple authors have pointed out that the apparent temporal association of CSM with CAD in case studies is due to protopathic bias. Protopathic bias is “when an exposure is delivered in the early prodrome of a disease before it is diagnosed” as defined by Cassidy et al. This sequence can lead to a mistaken inference of causation rather than coincidence.^38–45

No epidemiologic, pathological, or biomechanical studies have demonstrated that cervical CSM can cause CAD or dislodge a mural thrombus within a dissected artery.

Several highly powered epidemiologic studies, encompassing over 500 million person-years of data, consistently indicate that patients who experience vertebral or carotid dissection are equally likely to have visited a chiropractor or a primary care physician due to symptomatic expression, typically head or neck pain. These findings strongly indicate that CSM does not increase the risk of CAD or stroke.^{37,38,43,45–48}

Numerous biomechanical studies have shown that measured forces during skilled high-velocity, low-amplitude adjustments are lower than those of daily head movements and have not been shown to alter arterial integrity or blood flow.^{39–41,49–60} Accordingly, the thromboembolic (TE)-dislodgment theory remains physiologically implausible.

Collectively, these highly-powered studies indicate that CSM has a null effect as a cause of CAD or TE events and affirm the safety of CSM when performed by skilled practitioners. While we strongly encourage clinicians to remain vigilant for neurovascular compromise, spontaneous CAD, or other unusual vascular symptoms, unsubstantiated theories should not inform clinical practice or patient consent.

Advancing a CSM -thromboembolic (TE)-dislodgment theory without sufficient rigor lacks scientific credibility and may undermine evidence-based discourse. Until more compelling evidence of thrombus dislodgement after CSM is collected, we urge against promoting this hypothesis. Clinical decision-making and informed consent should be guided by objective evidence, which overwhelmingly demonstrates no causal relationship between CSM, CAD, TE, and stroke.
Respectfully submitted,

Jeffrey Wilder, DC, DABCO, James Demetrious, DC, DABCO, Phil Conway, DC, BPE, FCCPOR(C), David Graber, DC, DACBSP, Peter Tuchin, DC, PhD