Monthly Archives: August 2020
Misinformation seems to be everywhere and perhaps nowhere more intense than in so-called alternative medicine (SCAM). Correcting it is one of the main reasons/ambitions of this blog. But are such activities effective?
A meta-analysis estimated the efficacy of correcting health-related misinformation on social media. To better understand the causal relationship between exposure to corrective messages on social media and subsequent effects on health-related outcomes, the researchers restricted the meta-analysis to experimental studies that attempted to debunk health misinformation.
The findings indicate that correction can often mitigate the influence of misinformation but the size of the effect is usually small to moderate. The pooled effect was comparable with previous meta-analyses that focused on the correction of misinformation in contexts such as crime, politics, and science. The results provide no evidence of a so-called “boomerang” or backfire effect, whereby attempts to correct misinformation can unintentionally increase people’s acceptance of the falsehood.
The authors concluded that, although there is still much to be learned, the current study’s results are cause for optimism. The vast majority of corrective interventions are at least somewhat successful in diminishing the impact of misinformation, and our findings regarding moderating factors should inform future research into designing effective countermeasures. The continued efforts of the broader research community will only further refine our understanding of best practices to address the threat presented by health misinformation on social media.
What better motivator to carry on?
Steiner with his wife (right) and Ita Wegman, his lover (left).
Anthroposophic medicine was founded by Steiner and Ita Wegman in the early 20th century. Currently, it is being promoted as an extension of conventional medicine. Proponents claim that “its unique understanding of the interplay among physiological, soul and spiritual processes in healing and illness serves to bridge allopathy with naturopathy, homeopathy, functional/nutritional medicine and other healing systems.” Its value has repeatedly been questioned, and clinical research in this area is often less than rigorous.
Anthroposophic education was developed in the Waldorf school that was founded by Steiner in 1919 to serve the children of employees of the Waldorf-Astoria cigarette factory in Stuttgart, Germany. Pupils of Waldorf or Steiner schools, as they are also frequently called, are encouraged to develop independent thinking and creativity, social responsibility, respect, and compassion.
Waldorf schools implicitly infuse spiritual and mystic concepts into their curriculum. Like some other alternative healthcare practitioners – for instance, doctors promoting integrative medicine, chiropractors, homeopaths and naturopaths – some doctors of anthroposophic medicine take a stance against childhood immunizations. In a 2011 paper, I summarised the evidence which showed that in the UK, the Netherlands, Austria and Germany, Waldorf schools have been at the centre of measles outbreaks due to their stance regarding immunisations.
More recently, a study evaluated trends in rates of personal belief exemptions (PBEs) to immunization requirements for private kindergartens in California that practice alternative educational methods. The investigators used California Department of Public Health data on kindergarten PBE rates from 2000 to 2014 to compare annual average increases in PBE rates between schools.
Alternative schools had an average PBE rate of 8.7%, compared with 2.1% among public schools. Waldorf schools had the highest average PBE rate of 45.1%, which was 19 times higher than in public schools (incidence rate ratio = 19.1; 95% confidence interval = 16.4, 22.2). Montessori and holistic schools had the highest average annual increases in PBE rates, slightly higher than Waldorf schools (Montessori: 8.8%; holistic: 7.1%; Waldorf: 3.6%).
The authors concluded that Waldorf schools had exceptionally high average PBE rates, and Montessori and holistic schools had higher annual increases in PBE rates. Children in these schools may be at higher risk for spreading vaccine-preventable diseases if trends are not reversed.
As the world is hoping for the arrival of an effective vaccine against the corona virus, these figures should concern us.
I was notified via Twitter (thank you John) that the UK ‘United Lincolnshire Hospitals NHS Trust’ is looking to employ a spiritual healer or reiki therapist. For those who find this perhaps too hard to believe, I have copied a few excerpts from the advertisement:
- United Lincolnshire Hospitals NHS Trust
- Spiritual Healer / Reiki Therapist
- Lincoln County Hospital, Lincoln
- £21,892 – £24,157 per annum pro rata
An exciting opportunity has arisen for an Spiritual Healer / Reiki Therapist to join our friendly and energetic team on Waddington Unit. We are looking for a committed, enthusiastic and a self-motivated therapist to join our well established team.
Waddington Unit is a 26 bedded acute Haematology and Oncology ward that care for male and female patients. The ward has a high acuity, fast paced clinical admissions setting that cares for acutely unwell patients as a result of haematological and oncological conditions such as spinal cord compression and neutropenic sepsis as well as facilitating the delivery of chemotherapy.
We are passionate about improving patient experience and enhancing patients stay in hospital.
We are pleased to be working with The Sam Buxton Sunflower Healing Trust to offer this exciting opportunity on Waddington Unit.
If you are qualified and experienced as a Spiritual Healer /Reiki Therapist with 1 year or more of experience. To have completed the Healing In Hospital course, delivered by Angie Buxton-King and would like this opportunity to join this forward thinking team then please contact the co-ordinator for more information and an informal visit…
… ULHT is one of the largest hospital trusts in the country providing a comprehensive range of hospital based medical, surgical, paediatric, obstetric and gynaecological services to over 800,000 people across the county of Lincolnshire. The Trust’s core values are:
– Patient Centred
– Respect and
END OF QUOTE
The Sam Buxton Sunflower Healing Trust supports cancer patients and their families by providing funds to employ Complementary Therapists (Healers) in the NHS and Hospices. And Angie Buxton-King is a Reiki Master/ Teacher, Spiritual Healer, Author and Public Speaker. She also tells us this about her:
I am a fully qualified tutor of adults in the life learning sector and a Director/Trustee of our charity The Sam Buxton Sunflower Healing Trust ( SBSHT).
Since 2004 following the publication of my first book The NHS Healer; I have been invited to speak at many medical and holistic conferences. I am a past chair of The Doctor Healer Network and a former council member of The College of Medicine representing complementary therapies. Along with my husband Graham we created Energy Healing Training and Reiki Training that complies with National Occupational Standards. We have also created our unique ‘Healing in Hospitals & Hospices Training’ and ‘Delivering Complementary Therapy in a Statutory Setting Training’ to give healers and complementary therapists the necessary skills to work safely and competently in a more formal setting. I was employed by University College London Hospital (UCLH) as a Spiritual Healer to deliver healing to cancer patients as part of an integrated, holistic package of care for 12 years.
David Colquhoun published an excellent comment at the time about the UCLH work. All I want to add here is a list of suggestions to the ‘United Lincolnshire Hospitals NHS Trust’ regarding posts they might consider advertising in the future:
- ACUPUNCTURIST to run the department of anaesthesiology.
- FLYING CARPET MANAGER to relieve the over-worked Lincolnshire ambulance service.
- EXORCIST to deal with whistle blowers of all types.
- ALCHEMIST to turn lead into gold whenever the Trust runs into financial difficulties.
- HOMEOPATH to run the hospital pharmacy.
- QUANTUM PHYSICIST to maintain the ventilators of the IC unit.
- VIRTUAL SURGEON to head the department of surgery.
- VAMPIRE to organise the blood donation activities.
- DISCIPLE OF ANDREW WAKEFIELD to coordinate the Trust’s vaccination service.
- PRO-LIFE ACTIVIST to head the abortion service.
- SCIENTOLOGIST to run the spiritual well-being initiative.
- PSEUDOSCIENTIST to head the clinical trials unit.
- CAOS THEORIST to oversee the accounts.
- ELEPHANT to work in the porcelain shop.
In the interest of improving public health in Lincolnshire, I invite my readers to suggest further posts which might contribute profitably to the success of the ‘United Lincolnshire Hospitals NHS Trust’.
Tasuki is a sort of sash for holding up the sleeves on a kimono. It also retracts the shoulders and keeps the head straight up. By correcting the wearer’s posture, it might even prevent or treat neck pain. The greater the forward head posture, for example, the more frequent are neck problems. However, there is little clinical evidence to support or refute this hypothesis.
This study was conducted to determine whether Tasuki-style posture supporter improves neck pain compared to waiting-list. It was designed as an individually-randomized, open-label, waiting-list-controlled study. Adults with non-specific chronic neck pain who reported 10 points or more on modified Neck Disability Index (mNDI: range, 0-50; higher points indicate worse condition) were enrolled. Participants were randomly assigned 1:1 to the intervention group or to a waiting-list control group. The primary outcome was the change in mNDI at 1 week.
In total, 50 participants were enrolled. Of these participants, 26 (52%) were randomly assigned to the intervention group and 24 to the waiting-list. Attrition rate was low in both groups (1/50). The mean mNDI change score at 1 week was more favourable for Tasuki than waiting-list (between-group difference, -3.5 points (95% confidence interval (CI), -5.3 to -1.8); P = .0002). More participants (58%) had moderate benefit (at least 30% improvement) with Tasuki than with waiting-list (13%) (relative risk 4.6 (95% CI 1.5 to 14); risk difference 0.45 (0.22 to 0.68)).
The author concluded that this trial suggests that wearing Tasuki might moderately improve neck pain. With its low-cost, low-risk, and easy-to-use nature, Tasuki could be an option for those who suffer from neck pain.
In the previous two posts, we discussed how lamentably weak the evidence for acupuncture and spinal manipulation is regarding the management of pain such as ‘mechanical’ neck pain. Here we have a well-reported study with a poor design (no control for non-specific effects) which seems to suggest that simply wearing a Tasuki is just as effective as acupuncture or spinal manipulation.
What is the lesson from this collective evidence?
Is it that we should forget about acupuncture and spinal manipulation for chronic neck pain?
Or is it that poor trial designs generate unreliable evidence?
Or is it that any treatment, however daft, will generate positive outcomes, if the researchers are sufficiently convinced of its benefit?
Yes, I think so.
If you had chronic neck pain, would you rather have your neck manipulated, needles stuck into your body, or get a Tasuki? (Spoiler: Tasuki is risk-free, the other two treatments are not!)
As mentioned already yesterday, NICE published a draft report on pain treatments. The draft is now open to public consultation until 14 September 2020, and some of my readers might want to comment. It suggests that people with chronic primary pain (CPP) should not get pain-medication of any type, but be offered supervised group exercise programmes, some types of psychological therapy, or acupuncture.
No recommendation is made for manual therapy, but a lengthy document evaluates with the subject in some detail. Here are what I consider to be the key passages from its clinical evidence section:
Mixed modality manual therapy versus usual care/acupuncture/dry needling
Low quality evidence from 2 studies with a total of 52 participants showed no clinically important difference between mixed modality manual therapy and usual care at time points up to 3 months. Low quality evidence from 1 study with a total of 33 participants showed a clinically important benefit of mixed modality manual therapy over usual care at time points after 3 months. Low quality evidence from 1 study with a total of 26 participants showed no clinically important difference between mixed modality manual therapy and acupuncture/dry needling at time points up to 3 months.
Soft tissue technique versus usual care/acupuncture/dry needling
Low quality evidence from 3 studies with a total of 286 participants showed a clinically important benefit of soft tissue technique over usual care at time points up to 3 months. Very low quality evidence from 2 studies with a total of 115 participants showed a clinically important benefit of acupuncture/dry needling over soft tissue technique at time points up to 3 months.
Manipulation/mobilisation versus usual care/acupuncture/dry needling
Low quality evidence from 1 study with a total of 30 participants showed a clinically important benefit of manipulation/mobilisation over usual care at time points up to 3 months. Very low quality evidence from 1 study with a total of 24 participants showed no clinically important difference between manipulation/mobilisation and acupuncture/dry needling at time points up to 3 months.
Manual therapy interventions compared with each other
Moderate quality evidence from 1 study with a total of 63 participants showed a clinically important benefit of mixed modality manual therapy over soft tissue technique at time points up to 3 months. Low quality evidence from 1 study with a total of 63 participants showed a clinically important benefit of mixed modality manual therapy over soft tissue technique at time points after 3 months. Low quality evidence from 1 study with a total of 30 participants showed a clinically important benefit of mixed modality manual therapy over manipulation/mobilisation at time points up to 3 months. Very low quality evidence from 3 studies with a total of 125 participants showed a clinically important benefit of manipulation/mobilisation over soft tissue technique at time points up to 3 months. Low quality evidence from 1 study with a total of 68 participants showed no clinically important difference between manipulation/mobilisation and soft tissue technique at time points after 3 months.
In my view, this is a sound assessment of effectiveness. Nonetheless, I should to mention a few critical points.
Manual therapy is a very heterogeneous group of interventions. Massage and spinal manipulation, for instance, are very different in almost every respect. It would therefore be more constructive to name the techniques more precisely. Evaluating them together makes little sense to me and is hardly different from an assessment of all pharmacological treatments.
Much more important is the fact that the document lacks an assessment of harms. All I did find was a comment saying ‘THERE WAS NO EVIDENCE OF HARM’. This statement is certainly misleading. Perhaps the clinical trials did not report adverse effects, but this is (as I have often pointed out) because these studies usually defy research ethics by failing to mention them. As we have discussed ad nauseam on this blog (for instance here, here and here), spinal manipulation has regularly been associated with severe harms many times.
As NICE do not suggest to recommend manual therapy for CPP, this is perhaps not so crucial in this particular instance. However, I do believe that, for completeness of the evidence as well as for the credibility of the research, an in-depth assessment of the risks is paramount when it comes to the assessment of any therapy.
As recently reported, the most thorough review of the subject showed that the evidence for acupuncture as a treatment for chronic pain is very weak. Yesterday, NICE published a draft report that seems to somewhat disagree with this conclusion (and today, this is being reported in most of the UK daily papers). The draft is now open to public consultation until 14 September 2020 and many of my readers might want to comment.
The draft report essentially suggests that people with chronic primary pain (CPP) should not get pain-medication of any type, but be offered supervised group exercise programmes, some types of psychological therapy, or acupuncture. While I understand that chronic pain should not be treated with long-term pain-medications – I did even learn this in medical school all those years ago – one might be puzzled by the mention of acupuncture.
But perhaps we need first ask, WHAT IS CPP? The NICE report informs us that CPP represents chronic pain as a condition in itself and which can’t be accounted for by another diagnosis, or where it is not the symptom of an underlying condition (this is known as chronic secondary pain). I find this definition most unsatisfactory. Pain is usually a symptom and not a disease. In many forms of what we now call CPP, an underlying disease does exist but might not yet be identifiable, I suspect.
The evidence on acupuncture considered for the draft NICE report included conditions like:
- neck pain,
- myofascial pain,
- radicular arm pain,
- shoulder pain,
- prostatitis pain,
- mechanical neck pain,
I find it debatable whether these pain syndromes can be categorised to be without an underlying diagnosis. Moreover, I find it problematic to lump them together as though they were one big entity.
The NICE draft document is huge and far too big to be assessed in a blog like mine. As it is merely a draft, I also see little point in evaluating it or parts of in detail. Therefore, my comments are far from detailed, very brief and merely focussed on pain (the draft NICE report considers several further outcome measures).
There is a separate document for acupuncture, from which I copy what I consider the key evidence:
Acupuncture versus sham acupuncture
Very low quality evidence from 13 studies with 1230 participants showed a clinically
important benefit of acupuncture compared to sham acupuncture at ≤3 months. Low quality
evidence from 2 studies with 159 participants showed a clinically important benefit of
acupuncture compared to sham acupuncture at ≤3 months.
Low quality evidence from 4 studies with 376 participants showed no clinically important
difference between acupuncture and sham acupuncture at >3 months. Moderate quality
evidence from 2 studies with 159 participants showed a clinically important benefit of
acupuncture compared to sham acupuncture at >3 months. Low quality evidence from 1
study with 61 participants showed no clinically important difference between acupuncture
and sham acupuncture at >3 months.
As acupuncture has all the features that make a perfect placebo (slightly invasive, mildly painful, exotic, involves touch, time and attention), I see little point in evaluating its efficacy through studies that make no attempt to control for placebo effects. This is why the sham-controlled studies are central to the question of acupuncture’s efficacy, no matter for what condition.
Reading the above evidence carefully, I fail to see how NICE can conclude that CPP patients should be offered acupuncture. I am sure that some readers will disagree and am looking forward to reading their comments.
Together with a co-worker, Prof Walach conducted a systematic review of mistletoe extracts (Rudolf Steiner’s anti-cancer drug) as a treatment for improving the quality of life (QoL) of cancer patients. They included all prospective controlled trials that compared mistletoe extracts with a control in cancer patients and reported QoL or related dimensions.
Walach included 26 publications with 30 data sets. The studies were heterogeneous. The pooled standardized mean difference (random effects model) for global QoL after treatment with mistletoe extracts vs. control was d = 0.61 (95% CI 0.41-0.81, p < 0,00001). The effect was stronger for younger patients, with longer treatment, in studies with lower risk of bias, in randomized and blinded studies. Sensitivity analyses supported the validity of the finding. 50% of the QoL subdomains (e.g. pain, nausea) showed a significant improvement after mistletoe treatment. Most studies had a high risk of bias or at least raise some concern.
The authors concluded that mistletoe extracts produce a significant, medium-sized effect on QoL in cancer. Risk of bias in the analyzed studies is likely due to the specific type of treatment, which is difficult to blind; yet this risk is unlikely to affect the outcome.
This is a surprising conclusion, not least because – as reported on this blog – only a year ago another German team of researchers conducted a similar review and came to a very different conclusion. Here is their abstract again:
Purpose: One important goal of any cancer therapy is to improve or maintain quality of life. In this context, mistletoe treatment is discussed to be highly controversial. The aim of this systematic review is to give an extensive overview about the current state of evidence concerning mistletoe therapy of oncologic patients regarding quality of life and side effects of cancer treatments.
Methods: In September and October 2017, Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL and “Science Citation Index Expanded” (Web of Science) were systematically searched.
Results: The search strategy identified 3647 articles and 28 publications with 2639 patients were finally included in this review. Mistletoe was used in bladder cancer, breast cancer, other gynecological cancers (cervical cancer, corpus uteri cancer, and ovarian cancer), colorectal cancer, other gastrointestinal cancer (gastric cancer and pancreatic cancer), glioma, head and neck cancer, lung cancer, melanoma and osteosarcoma. In nearly all studies, mistletoe was added to a conventional therapy. Regarding quality of life, 17 publications reported results. Studies with better methodological quality show less or no effects on quality of life.
Conclusions: With respect to quality of life or reduction of treatment-associated side effects, a thorough review of the literature does not provide any indication to prescribe mistletoe to patients with cancer.
How can this discrepancy be explained? Which of the reviews is drawing the correct conclusion? Here are some relevant details that could help finding an answer to these questions:
- Walach is a psychologist by training, while the senior author of the 2019 review, Jutta Huebner, is an oncologist.
- Huebner included only randomised clinical trials (RCTs), whereas Walach included any interventional and non-interventional prospective controlled study.
- Huebner included 17 RCTs that reported QoL data, while Walach included 26 publications with 30 data sets including 5 non-randomised studies.
- Several of the primary studies had been published multiple times at different stages of completion. Walach included these as independent data sets, while Huebner included each study only once.
- Huebner looked at QoL, whereas Walach also considered measurements of self-regulation as outcome measures.
- Both reviews point out that the methodological quality of the primary studies was often poor; Walach drew a positive conclusion regardless, while Huebner did not and pointed out that studies with better methodology show less or no effects on quality of life or side effects of cancer therapy.
- Walach’s review was funded by funded by the Förderverein komplementärmedizinische Forschung, Arlesheim, Switzerland, a lobby group for mistletoe therapy, while Huebner’s work was funded by the German Guideline “S3 Leitlinie Komplementärmedizin in der Behandlung von onkologischen PatientInnen (Registernummer 032-055OL)” funded by the German Cancer Aid (Fördernummer 11583) within the German Guideline Program in Oncology and by the working group Prevention and Integrative Oncology of the German Cancer Society.
I am sure there are other important differences, but the ones listed above suffice, I think, to decide which of the two papers is trustworthy and which is not.
Non-specific chronic neck pain is a common condition. There is hardly a so-called alternative medicine (SCAM) that is not advocated for it. Amongst the most common approaches are manual therapy and therapeutic exercise. But which is more effective?
This study was aimed at answering the question by comparing the effects of manual therapy and therapeutic exercise. The short-term and mid-term effects produced by the two therapies on subjects with non-specific chronic neck pain were studied. The sample was randomized into three groups:
- spinal manipulation (n=22),
- therapeutic exercise (n=23),
- sham treatment (n=20).
The therapists were physiotherapists. Patients were not allowed any other treatments that the ones they were allocated to. Pain quantified by visual analogue scale, the pressure pain threshold, and cervical disability quantified by the Neck Disability Index (NDI) were the outcome measures. They were registered on week 1, week 4, and week 12.
No statistically significant differences were obtained between the experimental groups. Spinal manipulation improved perceived pain quicker than therapeutic exercise. Therapeutic exercise reduced cervical disability quicker than spinal manipulation. Effect size showed medium and large effects for both experimental treatments.
The authors concluded that there are no differences between groups in short and medium terms. Manual therapy achieves a faster reduction in pain perception than therapeutic exercise. Therapeutic exercise reduces disability faster than manual therapy. Clinical improvement could potentially be influenced by central processes.
The paper is poorly written (why do editors accept this?) but it laudably includes detailed descriptions of the three different interventions:
Group 1: Manual therapy
“Manual therapy” protocol was composed of three techniques based on scientific evidence for the treatment of neck pain. This protocol was applied in the three treatment sessions, one per week.
- 1.High thoracic manipulation on T4. Patients are positioned supine with their arms crossed in a “V” shape over the chest. The therapist makes contact with the fist at the level of the spinous process of T4 and blocks the patient’s elbows with his chest. Following this, he introduces flexion of the cervical spine until a slight tension is felt in the tissues at the point of contact. Downward and cranial manipulation is applied. If cavitation is not achieved on the first attempt, the therapist repositions the patient and performs a second manipulation. A maximum of two attempts will be allowed in each patient.
- 2.Cervical articular mobilization (2 Hz, 2 min × 3 series). The patient is placed on the stretcher in a prone position, placing both hands under his forehead. The therapist makes contact with his two thumbs on the spinous process of the patient’s C2 vertebra and performs grade III posteroanterior impulses at a speed of 2 Hz and for 2 min. There are 3 mobilization intervals with a minute of rest between each one of them .
- 3.Suboccipital muscle inhibition (3 min). With the patient lying supine, the therapist places both hands under the subject’s head, by contacting their fingers on the lower edge of the occipital bone, and exerts constant and painless pressure in the anterior and cranial direction for 3 min.
Group 2: Therapeutic exercise
“Therapeutic exercise” protocol: this protocol is based on a progression in load composed of different phases: at first, activation and recruitment of deep cervical flexors; secondly, isometric exercise deep and superficial flexors co-contraction, and finally, eccentric recruitment of flexors and extensors. This protocol, as far as we know, has not been studied, but activation of this musculature during similar tasks to those of our protocol has been observed. This protocol was taught to patients in the first session and was performed once a day during the 3 weeks of treatment, 21 sessions in total. It was reinforced by the physiotherapist in each of the three individual sessions.
Week 1: Exercises 1 and 2.
- 1.Cranio-cervical flexion (CCF) in a supine position with a towel in the posterior area of the neck (3 sets, 10 repetitions, 10 s of contraction each repetition with 10 s of rest).
- 2.CCF sitting (3 sets, 10 repetitions, 10 s of contraction each repetition with 10 s of rest)
Week 2: Exercises 1, 2, 3, and 4.
- 3.Co-contraction of deep and superficial neck flexors in supine decubitus (10 repetitions, 10 s of contraction with 10 s of rest).
- 4.Co-contraction of flexors, rotators, and lateral flexors. The patients performed cranio-cervical flexion, while the physiotherapist asked him/her to tilt, rotate, and look towards the same side while he/she opposes a resistance with his/her hand (10 repetitions, 10 s of contraction with 10 s of rest).
Week 3: Exercises 1, 2, 3, 4, 5, and 6.
- 5.Eccentric for extensors. With the patient seated, he/she should perform cervical extension. Then, he/she must realize a CCF and finish doing a cervical flexion (10 repetitions).
- 6.Eccentric for flexors. The patients, placed in a quadrupedal and neutral neck position, should perform neck flexion; then, they must have done a cranio-cervical flexion and, maintaining that posture, extend the neck and then finally lose the CCF (10 repetitions).
Group 3: Sham treatment
For the “control” protocol, the patients were placed in the supine position, while the physiotherapist placed his hands without therapeutic intention on the patient’s neck for 3 min. The physiotherapist simulated the technique of suboccipital inhibition. Later, with the laser pointer off, patients were contacted without exerting pressure for 10 s. Patients assigned to the control group received treatment 1 or 2 after completing the study.
This study has many strengths and several weaknesses (for instance the small sample sizes). Its results are not surprising. They confirm what I have been pointing out repeatedly, namely that, because exercise is cheaper and has less potential for harm, it is by far a better treatment for chronic neck pain than spinal manipulation.