Chiropractors and osteopaths have long tried to convince us that spinal manipulation and mobilisation are the best we can do when suffering from neck pain. But is this claim based on good evidence?
This recent update of a Cochrane review was aimed at assessing the effects of manipulation or mobilisation alone compared with those of an inactive control or another active treatment on pain, function, disability, patient satisfaction, quality of life and global perceived effect in adults experiencing neck pain with or without radicular symptoms and cervicogenic headache (CGH) at immediate- to long-term follow-up, and when appropriate, to assess the influence of treatment characteristics (i.e. technique, dosage), methodological quality, symptom duration and subtypes of neck disorder on treatment outcomes.
Review authors searched the following computerised databases to November 2014 to identify additional studies: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). They also searched ClinicalTrials.gov, checked references, searched citations and contacted study authors to find relevant studies.
Randomised controlled trials (RCTs) undertaken to assess whether manipulation or mobilisation improves clinical outcomes for adults with acute/subacute/chronic neck pain were included in this assessment.
Two review authors independently selected studies, abstracted data, assessed risk of bias and applied Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methods (very low, low, moderate, high quality). The authors calculated pooled risk ratios (RRs) and standardised mean differences (SMDs).
Fifty-one trials with a total of 2920 participants could be included. The findings are diverse. Cervical manipulation versus inactive control: For subacute and chronic neck pain, a single manipulation (three trials, no meta-analysis, 154 participants, ranged from very low to low quality) relieved pain at immediate- but not short-term follow-up. Cervical manipulation versus another active treatment: For acute and chronic neck pain, multiple sessions of cervical manipulation (two trials, 446 participants, ranged from moderate to high quality) produced similar changes in pain, function, quality of life (QoL), global perceived effect (GPE) and patient satisfaction when compared with multiple sessions of cervical mobilisation at immediate-, short- and intermediate-term follow-up. For acute and subacute neck pain, multiple sessions of cervical manipulation were more effective than certain medications in improving pain and function at immediate- (one trial, 182 participants, moderate quality) and long-term follow-up (one trial, 181 participants, moderate quality). These findings are consistent for function at intermediate-term follow-up (one trial, 182 participants, moderate quality). For chronic CGH, multiple sessions of cervical manipulation (two trials, 125 participants, low quality) may be more effective than massage in improving pain and function at short/intermediate-term follow-up. Multiple sessions of cervical manipulation (one trial, 65 participants, very low quality) may be favoured over transcutaneous electrical nerve stimulation (TENS) for pain reduction at short-term follow-up. For acute neck pain, multiple sessions of cervical manipulation (one trial, 20 participants, very low quality) may be more effective than thoracic manipulation in improving pain and function at short/intermediate-term follow-up. Thoracic manipulation versus inactive control: Three trials (150 participants) using a single session were assessed at immediate-, short- and intermediate-term follow-up. At short-term follow-up, manipulation improved pain in participants with acute and subacute neck pain (five trials, 346 participants, moderate quality, pooled SMD -1.26, 95% confidence interval (CI) -1.86 to -0.66) and improved function (four trials, 258 participants, moderate quality, pooled SMD -1.40, 95% CI -2.24 to -0.55) in participants with acute and chronic neck pain. A funnel plot of these data suggests publication bias. These findings were consistent at intermediate follow-up for pain/function/quality of life (one trial, 111 participants, low quality). Thoracic manipulation versus another active treatment: No studies provided sufficient data for statistical analyses. A single session of thoracic manipulation (one trial, 100 participants, moderate quality) was comparable with thoracic mobilisation for pain relief at immediate-term follow-up for chronic neck pain. Mobilisation versus inactive control: Mobilisation as a stand-alone intervention (two trials, 57 participants, ranged from very low to low quality) may not reduce pain more than an inactive control. Mobilisation versus another active treatment: For acute and subacute neck pain, anterior-posterior mobilisation (one trial, 95 participants, very low quality) may favour pain reduction over rotatory or transverse mobilisations at immediate-term follow-up. For chronic CGH with temporomandibular joint (TMJ) dysfunction, multiple sessions of TMJ manual therapy (one trial, 38 participants, very low quality) may be more effective than cervical mobilisation in improving pain/function at immediate- and intermediate-term follow-up. For subacute and chronic neck pain, cervical mobilisation alone (four trials, 165 participants, ranged from low to very low quality) may not be different from ultrasound, TENS, acupuncture and massage in improving pain, function, QoL and participant satisfaction at immediate- and intermediate-term follow-up. Additionally, combining laser with manipulation may be superior to using manipulation or laser alone (one trial, 56 participants, very low quality).
Confused? So am I!
In my view, these analyses show that the quality of most studies is wanting and the evidence is weak – much weaker than chiropractors and osteopaths try to make us believe. It seems to me that no truly effective treatments for neck pain have been discovered and that therefore manipulation/mobilisation techniques are as good or as bad as most other options.
In such a situation, it might be prudent to first investigate the causes of neck pain in greater detail and subsequently determine the optimal therapies for each of them. Neck pain is a SYMPTOM, not a disease! And it is always best to treat the cause of a symptom rather than pretending we know the cause as chiropractors and osteopaths often do.
The authors of the Cochrane review seem to agree with this view at least to some extent. They conclude that although support can be found for use of thoracic manipulation versus control for neck pain, function and QoL, results for cervical manipulation and mobilisation versus control are few and diverse. Publication bias cannot be ruled out. Research designed to protect against various biases is needed. Findings suggest that manipulation and mobilisation present similar results for every outcome at immediate/short/intermediate-term follow-up. Multiple cervical manipulation sessions may provide better pain relief and functional improvement than certain medications at immediate/intermediate/long-term follow-up. Since the risk of rare but serious adverse events for manipulation exists, further high-quality research focusing on mobilisation and comparing mobilisation or manipulation versus other treatment options is needed to guide clinicians in their optimal treatment choices.
The call for further research is, of course, of no help for patients who are suffering from neck pain today. What would I recommend to them?
My advice is to be cautious:
- Consult your doctor and try to get a detailed diagnosis.
- See a physiotherapist and ask to be shown exercises aimed at reducing the pain and preventing future episodes.
- Do these exercises regularly, even when you have no pain.
- Make sure you do whatever else might be needed in terms of life-style changes (ergonomic work place, correct sleeping arrangements, etc.).
- If you are keen on seeing an alternative practitioner for manual therapy, consult a osteopath rather than a chiropractor; the former tend to employ techniques which are less risky than the latter.
- Avoid both chiropractors and long-term medication for neck pain.
The aim of this study was to evaluate clinical effectiveness of Alexander Technique lessons or acupuncture versus usual care for persons with chronic, nonspecific neck pain.
Patients with neck pain lasting at least 3 months, a score of at least 28% on the Northwick Park Questionnaire (NPQ) for neck pain and associated disability, and no serious underlying pathology were randomised to receive 12 acupuncture sessions or 20 one-to-one Alexander lessons (both 600 minutes total) plus usual care versus usual care alone. The NPQ score at 0, 3, 6, and 12 months (primary end point) and Chronic Pain Self-Efficacy Scale score, quality of life, and adverse events (secondary outcomes) served as outcome measures. 517 patients were recruited. Their median duration of neck pain was 6 years. Mean attendance was 10 acupuncture sessions and 14 Alexander lessons. Between-group reductions in NPQ score at 12 months versus usual care were 3.92 percentage points for acupuncture (95% CI, 0.97 to 6.87 percentage points) (P = 0.009) and 3.79 percentage points for Alexander lessons (CI, 0.91 to 6.66 percentage points) (P = 0.010). The 12-month reductions in NPQ score from baseline were 32% for acupuncture and 31% for Alexander lessons. Participant self-efficacy improved for both interventions versus usual care at 6 months (P < 0.001) and was significantly associated (P < 0.001) with 12-month NPQ score reductions (acupuncture, 3.34 percentage points [CI, 2.31 to 4.38 percentage points]; Alexander lessons, 3.33 percentage points [CI, 2.22 to 4.44 percentage points]). No reported serious adverse events were considered probably or definitely related to either intervention.
The authors drew the following conclusions: acupuncture sessions and Alexander Technique lessons both led to significant reductions in neck pain and associated disability compared with usual care at 12 months. Enhanced self-efficacy may partially explain why longer-term benefits were sustained.
Where to begin? There is much to be criticised about this study!
For starters, the conclusions are factually wrong. They should read “acupuncture sessions plus usual care and Alexander Technique lessons plus usual care both led to significant reductions in neck pain and associated disability compared with usual care at 12 months. Enhanced self-efficacy may partially explain why longer-term benefits were sustained.
On this blog, we have repeatedly discussed the ‘A+B versus B’ study design and the fact that it cannot provide information about cause and effect because it fails to control for placebo effects and the extra attention, time and empathy (for instance here and here). I suspect that this is the reason why it is so very popular in alternative medicine. It can make ineffective therapies appear to be effective.
Another point is a more clinical concern. Neck pain is not a disease, it is a symptom. In medicine we should, whenever possible, try to treat the cause of the underlying condition and not the symptom. Acupuncture is at best a symptomatic treatment. Usual care is often not very effective because we normally fail to see the cause of neck pain. In my view, alternative treatments should either be tested against placebo or sham interventions or against optimal care.
What is optimal care for nonspecific neck pain? As its causes are often unclear and usually multifactorial, the optimal treatment needs to be multifactorial (one could also call it holistic) as well. The causes often range from poor ergometric conditions at work to muscular tension, stress, psychological problems etc. Thus optimal care would be a team work tailor-made for each patient possibly including physiotherapists, pain specialists, clinical psychologists, orthopaedic surgeons etc.
My points here are:
- neither acupuncture nor Alexander technique take account of this complexity,
- they claim to be holistic but, in fact, this turns out to be merely a good sales-slogan,
- usual care is usually no good,
- if pragmatic trials using the ‘A+B versus B’ design make any sense at all, they should employ not usual care but optimal care for the control group.
In the end, we are left with a study that looks fairly rigorous at first sight, but that really tells us next to nothing (except that dedicating 600 minutes to patients in pain is not without effect). I am truly surprised that a top journal like the Annals of Internal Medicine decided to publish it.
Alternative medicine encompasses many bizarre treatments, but one of the weirdest must be craniosacral therapy (CST). The assumptions underlying CTS are:
- light manual touch of the head moves the joints of the cranium;
- this movement stimulates the flow of the cerebrospinal fluid;
- the enhanced flow has profound and positive effects on human health.
None of these assumptions are supported by evidence. In fact, they are as implausible as assumptions in alternative medicine get.
CST was developed by the osteopath John Upledger, D.O. in the 1970s, as an offshoot osteopathy in the cranial field, or cranial osteopathy, which was developed in the 1930s by William Garner Sutherland. Apart from this confusing terminology, we are also confronted with a confusing array of therapeutic claims; CST seems to be recommended for most conditions.
And the evidence? As good as none!
This is why any new trial is worth a mention. A recent study tested CST in comparison to sham treatment in chronic non-specific neck pain patients. 54 blinded patients were randomized to either 8 weekly units of CST or light touch sham treatment. Outcomes were assessed before and after treatment (week 8) and a further 3 months later (week 20). The primary outcome was pain intensity on a visual analogue scale; secondary outcomes included pain on movement, pressure pain sensitivity, functional disability, health-related quality of life, well-being, anxiety, depression, stress perception, pain acceptance, body awareness, patients’ global impression of improvement and safety.
In comparison to sham, CST patients reported significant and clinically relevant effects on pain intensity at week 8 as well as at week 20. Minimal clinically important differences in pain intensity at week 20 were reported by 78% of the CST patients, while 48% even had substantial clinical benefit. Significant differences at week 8 and 20 were also found for pain on movement, functional disability, physical quality of life and patients’ global improvement. Pressure pain sensitivity and body awareness were significantly improved only at week 8; anxiety only at week 20. No serious adverse events were reported.
The authors from the Department of Internal and Integrative Medicine, University of Duisburg-Essen and the Institute of Integrative Medicine, University of Witten/Herdecke, Germany, concluded that CST was both specifically effective and safe in reducing neck pain intensity and may improve functional disability and quality of life up to 3 months post intervention.
Oddly, this is not even close to the conclusion I am going to draw: inadequate control for placebo and other non-specific effects generated a false-positive result.
Who is correct?
I suggest we wait for an independent replication to decide.
Some people seem to believe that the field of alternative medicine resembles a quaint little cottage industry where money hardly matters. A new analysis shows how far from the truth this impression is.
In the 2007 US National Health Interview Survey, use of complementary health approaches, reasons for this use, and associated out of pocket (OOP) costs were captured in a nationally representative sample of 5,467 US adults. Ordinary least square regression models that controlled for co-morbid conditions were used to estimate aggregate and per person OOP costs associated with 14 painful health conditions.
The analyses suggest that individuals using complementary approaches spent a total of $14.9 billion OOP on these approaches to manage three painful conditions: arthritis, back pain and fibromyalgia. Around 7.5 billion of that total was spent on consulting practitioners such as chiropractors and acupuncturists. Total OOP expenditures seen in those using complementary approaches for their back pain ($8.7 billion) far outstripped that of any other condition, with the majority of these costs ($4.7 billion) resulting from visits to complementary providers. Annual condition-specific per-person OOP costs varied from a low of $568 for regular headaches, to a high of $895 for fibromyalgia. The total expenditure on complementary medicine was comparable to that on conventional care.
The authors concluded that adults in the United States spent $14.9 billion OOP on complementary health approaches (e.g., acupuncture, chiropractic, herbal medicines) to manage painful conditions including back pain ($8.7 billion). This back pain estimate is almost 1/3rd of total conventional healthcare expenditures for back pain ($30.4 billion) and 2/3rds higher than conventional OOP expenditures ($5.1 billion).
These are truly eye-watering sums. The obvious question is: IS THIS MONEY WELL-SPENT?
The short answer, I fear, is NO!
The alternative therapies in question are not based on compelling evidence in the management of these painful conditions. Some are clearly not better than placebo, and others are apparently supported by some research but its quality is hardly good enough to rely upon.
This level expenditure is both impressive and worrying. It highlights an enormous waste of resources, alerts us to an urgent need for truly rigorous research, and demonstrates how high the stakes really are.
Nonspecific neck pain is extremely common, often disabling, and very costly for us all. If we believe those who earn their money with them, effective treatments for the condition abound. One of these therapies is osteopathy. But does osteopathic manipulation/mobilisation really work?
The objective of a recent review (the link I originally put in here does not work, I will supply a new one as soon as the article becomes available on Medline) was to find out. Specifically, the authors wanted to assess the effectiveness of osteopathic manipulative treatment (OMT) in the management of chronic nonspecific neck pain regarding pain, functional status, and adverse events.
Electronic literature searches unrestricted by language were performed in March 2014. A manual search of reference lists and personal communication with experts identified additional studies. Only randomized clinical trials (RCTs) were included, and studies of specific neck pain or single treatment techniques were excluded. Primary outcomes were pain and functional status, and secondary outcome was adverse events.
Studies were independently reviewed using a standardized data extraction form. Mean difference (MD) or standard mean difference (SMD) with 95% confidence intervals (CIs) and overall effect size were calculated for primary outcomes. GRADE was used to assess quality of the evidence.
Of 299 identified articles, 18 were evaluated and 15 excluded. The three included RCTs had low risk of bias. The results show that moderate-quality evidence suggested OMT had a significant and clinically relevant effect on pain relief (MD: -13.04, 95% CI: -20.64 to -5.44) in chronic nonspecific neck pain, and moderate-quality evidence suggested a non-significant difference in favour of OMT for functional status (SMD: -0.38, 95% CI: -0.88 to -0.11). No serious adverse events were reported.
The authors concluded that, based on the three included studies, the review suggested clinically relevant effects of OMT for reducing pain in patients with chronic nonspecific neck pain. Given the small sample sizes, different comparison groups, and lack of long-term measurements in the few available studies, larger, high-quality randomized controlled trials with robust comparison groups are recommended.
Yet again I am taken aback by several things simultaneously:
- the extreme paucity of RCTs, particularly considering that neck pain is one of the main indication for osteopaths,
- the rather uncritical text by the authors,
- the nonsensical conclusions.
Let me offer my own conclusions which are, I hope, a little more realistic:
GIVEN THE PAUCITY OF THE RCTs AND THEIR SMALL SAMPLE SIZES, IT IS NOT POSSIBLE TO CLAIM THAT OMT FOR NONSPECIFIC NECK PAIN IS AN EVIDENCE-BASED APPROACH
On this blog, we have discussed the Alexander Technique before; it is an educational method promoted for all sorts of conditions, including neck pain. The very first website I found when googling it stated the following: “Back and neck pain can be caused by poor posture. Alexander Technique lessons help you to understand how to improve your posture throughout your daily activities. Many people, even those with herniated disc or pinched nerve, experience relief after one lesson, often permanent relief after five or ten lessons.”
Sounds too good to be true? Is there any good evidence?
The aim of this study, a randomized controlled trial with 3 parallel groups, was to test the efficacy of the Alexander Technique, local heat and guided imagery on pain and quality of life in patients with chronic non-specific neck pain. A total of 72 patients (65 females, 40.7±7.9 years) with chronic, non-specific neck pain were recruited. They received 5 sessions of the Alexander Technique, while the control groups were treated with local heat application or guided imagery. All interventions were conducted once a week for 45 minutes each.
The primary outcome measure at week 5 was neck pain intensity quantified on a 100-mm visual analogue scale; secondary outcomes included neck disability, quality of life, satisfaction and safety. The results show no group differences for pain intensity for the Alexander Technique compared to local heat. An exploratory analysis revealed the superiority of the Alexander Technique over guided imagery. Significant group differences in favor of the Alexander Technique were also found for physical quality of life. Adverse events were mild and mainly included slightly increased pain and muscle soreness.
The authors concluded that Alexander Technique was not superior to local heat application in treating chronic non-specific neck pain. It cannot be recommended as routine intervention at this time. Further trials are warranted for conclusive judgment.
I am impressed with these conclusions: this is how results should be interpreted. The primary outcome measure failed to yield a significant effect, and therefore such a negative conclusion is the only one that can be justified. Yet such clear words are an extreme rarity in the realm of alternative medicine. Most researchers in this area would, in my experience, have highlighted the little glimpses of the possibility of a positive effect and concluded that this therapeutic approach may be well worth a try.
In my view, this article is a fine example for demonstrating the difference between true scientists (who aim at testing the effectiveness of interventions) and pseudo-scientists (who aim at promoting their pet therapy). I applaud the authors of this paper!
Neck pain is a common problem which often causes significant disability. Chiropractic manipulation has become one of the most popular forms of alternative treatment for such symptoms. This seems surprising considering that neck manipulations are neither convincingly effective nor free of adverse effects.
The current Cochrane review on this subject could not be clearer: “Done alone, manipulation and/or mobilization were not beneficial; when compared to one another, neither was superior.” In the absence of compelling evidence for efficacy, any risk of neck manipulation would tilt the risk/benefit balance into the negative.
Adverse effects of neck manipulations range from mild symptoms, such as local neck tenderness or stiffness, to more severe injuries involving the spinal cord, peripheral nerve roots, and arteries within the neck. A recent paper reminds us that another serious complication has to be added to this already long list: phrenic nerve injury.
The phrenic nerve is responsible for controlling the contractions of the diaphragm, which allows the lungs to take in and release air and make us breathe properly. The phrenic nerve is formed from C3, C4, and C5 nerve fibres and descends along the anterior surface of the scalenus anterior muscle before entering the thorax to supply motor and sensory input to the diaphragm. Its anatomic location in the neck leaves it vulnerable to traumatic injury. Phrenic nerve injury can result in paralysis of the diaphragm and often leads to deteriorating function of the diaphragm, which can lead to partial or complete paralysis of the muscle and, as a result, serious breathing problems.
Patients who experience such problems may require emergency medical treatment or surgery. Sudden, severe damage to the phrenic nerve can make it impossible for the diaphragm to contract on its own. In order to make sure that the patient can breathe, a breathing tube needs to be inserted, a process called intubation. Artificial respiration would then be required.
American neurologists published a case report of a healthy man who consulted a chiropractor for his neck pain. Predictably, the chiropractor employed cervical manipulation to treat this condition. The result was bilateral diaphragmatic paralysis.
Similar cases have been reported previously, for instance, here and here and here and here. Damage to other nerves has also been documented to be a possible complication of spinal manipulation, for instance, here and here.
The authors of this new case report conclude that physicians must be aware of this complication and should be cautious when recommending spinal manipulation for the treatment of neck pain, especially in the presence of preexisting degenerative disease of the cervical spine.
I know what my chiropractic friends will respond to this post:
- I am alarmist,
- I cherry-pick articles that are negative for their profession,
- these cases are extreme rarities,
- conventional medicine is much more dangerous.
To this I reply: Imagine a conventional therapy about which the current Cochrane review says that it has no proven effect for the condition in question. Imagine further that this therapy causes mild to moderate adverse effects in about 50% of all patients in addition to very dramatic complications which are probably rare but, as no monitoring system exists, of unknown frequency. Imagine now that the professionals using this treatment more regularly than any other clinicians steadfastly deny that the risk/benefit balance is way out of kilter.
Would you call someone who repeatedly tries to warn the public of this situation ‘alarmist’?
Would you not consider the professionals who continue to practice the therapy in question to be irresponsible?
Iyengar Yoga, named after and developed by B. K. S. Iyengar, is a form of Hatha Yoga that has an emphasis on detail, precision and alignment in the performance of posture (asana) and breath control (pranayama). The development of strength, mobility and stability is gained through the asanas.
B.K.S. Iyengar has systematised over 200 classical yoga poses and 14 different types of Pranayama (with variations of many of them) ranging from the basic to advanced. This helps ensure that students progress gradually by moving from simple poses to more complex ones and develop their mind, body and spirit step by step.
Iyengar Yoga often makes use of props, such as belts, blocks, and blankets, as aids in performing asanas (postures). The props enable students to perform the asanas correctly, minimising the risk of injury or strain, and making the postures accessible to both young and old.
Sounds interesting? But does it work?
The objective of this recent systematic review was to conduct a systematic review of the existing research on Iyengar yoga for relieving back and neck pain. The authors conducted extensive literature searches and found 6 RCTs that met the inclusion criteria.
The difference between the groups on the post-intervention pain or functional disability intensity assessment was, in all 6 studies, favouring the yoga group, which projected a decrease in back and neck pain.
The authors concluded that Iyengar yoga is an effective means for both back and neck pain in comparison to control groups. This systematic review found strong evidence for short-term effectiveness, but little evidence for long-term effectiveness of yoga for chronic spine pain in the patient-centered outcomes.
So, if we can trust this evidence (I would not call the evidence ‘strong), we have yet another treatment that might be effective for acute back and neck pain. The trouble, I fear, is not that we have too few such treatments, the trouble seems to be that we have too many of them. They all seem similarly effective, and I cannot help but wonder whether, in fact, they are all similarly ineffective.
Regardless of the answer to this troubling question, I feel the need to re-state what I have written many times before: FOR A CONDITION WITH A MULTITUDE OF ALLEGEDLY EFFECTIVE THERAPIES, IT MIGHT BE BEST TO CHOSE THE ONE THAT IS SAFEST AND CHEAPEST.
The very first article on a subject related to alternative medicine with a 2015 date that I came across is a case-report. I am afraid it will not delight our chiropractic friends who tend to deny that their main therapy can cause serious problems.
In this paper, US doctors tell the story of a young woman who developed headache, vomiting, diplopia, dizziness, and ataxia following a neck manipulation by her chiropractor. A computed tomography scan of the head was ordered and it revealed an infarct in the inferior half of the left cerebellar hemisphere and compression of the fourth ventricle causing moderately severe, acute obstructive hydrocephalus. Magnetic resonance angiography showed severe narrowing and low flow in the intracranial segment of the left distal vertebral artery. The patient was treated with mannitol and a ventriculostomy. Following these interventions, she made an excellent functional recovery.
The authors of the case-report draw the following conclusions: This report illustrates the potential hazards associated with neck trauma, including chiropractic manipulation. The vertebral arteries are at risk for aneurysm formation and/or dissection, which can cause acute stroke.
I can already hear the counter-arguments: this is not evidence, it’s an anecdote; the evidence from the Cassidy study shows there is no such risk!
Indeed the Cassidy study concluded that vertebral artery accident (VBA) stroke is a very rare event in the population. The increased risks of VBA stroke associated with chiropractic and primary care physician visits is likely due to patients with headache and neck pain from VBA dissection seeking care before their stroke. We found no evidence of excess risk of VBA stroke associated chiropractic care compared to primary care. That, of course, was what chiropractors longed to hear (and it is the main basis for their denial of risk) – so much so that Cassidy et al published the same results a second time (most experts feel that this is a violation of publication ethics).
But repeating arguments does not make them more true. What we should not forget is that the Cassidy study was but one of several case-control studies investigating this subject. And the totality of all such studies does not deny an association between neck manipulation and stroke.
Much more important is the fact that a re-analysis of the Cassidy data found that prior studies grossly misclassified cases of cervical dissection and mistakenly dismissed a causal association with manipulation. The authors of this new paper found a classification error of cases by Cassidy et al and they re-analysed the Cassidy data, which reported no association between spinal manipulation and cervical artery dissection (odds ratio [OR] 5 1.12, 95% CI .77-1.63). These re-calculated results reveal an odds ratio of 2.15 (95% CI.98-4.69). For patients less than 45 years of age, the OR was 6.91 (95% CI 2.59-13.74). The authors of the re-analysis conclude as follows: If our estimates of case misclassification are applicable outside the VA population, ORs for the association between SMT exposure and CAD are likely to be higher than those reported using the Rothwell/Cassidy strategy, particularly among younger populations. Future epidemiologic studies of this association should prioritize the accurate classification of cases and SMT exposure.
I think they are correct; but my conclusion of all this would be more pragmatic and much simpler: UNTIL WE HAVE CONVINCING EVIDENCE TO THE CONTRARY, WE HAVE TO ASSUME THAT CHIROPRACTIC NECK MANIPULATION CAN CAUSE A STROKE.
Some chiropractors claim that their main intervention, spinal manipulation, works for nonspecific neck pain by improving inter-vertebral range of motion (IV-RoM). But IV-RoM is difficult to measure, and whether it is related to clinical outcomes seems uncertain. Researchers from the Institute of Musculoskeletal Research & Clinical Implementation and the Anglo-European College of Chiropractic have just published a study that might throw some light on this issue. According to its authors, it was aimed at answering the following research questions:
- Does cervical spine flexion and extension IV-RoM increase after a course of spinal manipulation?
- Is there a relationships between any IV-RoM increases and clinical outcomes?
- How does palpation compare with objective measurement in the detection of hypo-mobile segments?
Thirty patients with nonspecific neck pain and 30 healthy controls matched for age and gender received quantitative fluoroscopy (QF) screenings to measure flexion and extension IV-RoM (C1-C6) at baseline and 4-week follow-up. Patients received up to 12 neck manipulations and completed NRS, NDI and Euroqol 5D-5L at baseline, plus PGIC and satisfaction questionnaires at follow-up. IV-RoM accuracy, repeatability and hypo-mobility cut-offs were determined. Minimal detectable changes (MDC) over 4 weeks were calculated from controls. Patients and control IV-RoMs were compared at baseline as well as changes in patients over 4 weeks. Correlations between outcomes and the number of manipulations received and the agreement (Kappa) between palpated and QF-detected of hypo-mobile segments were calculated.
QF had high accuracy (worst RMS error 0.5σ) and repeatability (highest SEM 1.1σ, lowest ICC 0.9σ) for IV-RoM measurement. Hypo-mobility cut offs ranged from 0.8σ to 3.5σ. No outcome was significantly correlated with increased IV-RoM above MDC and there was no significant difference between the number of hypo-mobile segments in patients and controls at baseline or significant increases in IV-RoMs in patients. However, there was a modest and significant correlation between the number of manipulations received and the number of levels and directions whose IV-RoM increased beyond MDC (Rho=0.39, p=0.043). There was also no agreement between palpation and QF in identifying hypo-mobile segments (Kappa 0.04-0.06).
The authors concluded that this study found no differences in cervical sagittal IV-RoM between patients with non-specific neck pain and matched controls. There was a modest dose-response relationship between the number of manipulations given and number of levels increasing IV-RoM – providing evidence that neck manipulation has a mechanical effect at segmental levels. However, patient-reported outcomes were not related to this.
This conclusion seems a little odd to me. In my view the study suggests a clearly negative answer to all the three research questions formulated above. An interesting paragraph from the authors’ discussion section provides further insight: The lack of a relationship between symptomatic improvement and increased IV-RoM is also of interest. Clearly other mechanisms that improved the comfort and functional capacity of the patients in this study were in play, including spontaneous recovery. Other important biological factors may have included chemical factors in joint and muscle and activation patterns in the latter. However, this study seemed to rule out central pain hypersensitivity as a factor, as this was not detected at baseline in any of the patients. Psychological and social factors and their influence on functional behavior may also have had a role and may have been influenced by the interventions received.
So, spinal manipulation does not seem to work by improving IV-RoM. Could this be because spinal manipulation does not work at all?