Perspectives:   An Overview of Comparative Considerations of Cerebrovascular Accidents

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PETER L. ROME

ABSTRACT: This paper seeks to contrast reports concerning major adverse side effects, viz. cerebrovascular accidents (CVAs) attributed to cervical spine manipulation, within a broad perspective of medical procedures. It also seeks to correlate the incidence rates of other adverse events and medical procedures with the general incidence rate of CVAs. On analysis, an accurate position would indicate that cervical spinal manipulation is one of the more conservative, least invasive and safest of procedures in the provision of human health care services. The paper also alludes to the political connotations on the subject.

INDEX TERMS: MeSH: ARTERIES; CEREBROVASCULAR DISORDERS; CERVICAL VERTEBRAE; CHIROPRACTIC; MANIPULATION, ORTHOPEDIC; IATROGENIC DISEASE; ORTHOPEDICS; OSTEOPATHIC MEDICINE; PERSUASIVE COMMUNICATION; PHYSICAL THERAPY; SPINE; VERTEBROBASILAR ACCIDENTS.


Peter L. Rome, D.C.
Private practice of chiropractic Mount Waverley, Victoria
Received 26 March 1999, accepted 14 May 1999.
Chiropr J Aust 1999;   29 (3):   87—102
A FULL TEXT version of this paper is available in Word Format(182 KB)

INTRODUCTION

There can be a risk involved with virtually all medical procedures, from the taking of blood samples, ¹ use of vitamins ² and "natural" medications, ³ to vaccinations, ⁴ drugs ² and surgery. ⁵ At times, these risks seem to be either disregarded or categorised as an acceptable adverse side effect — the risk/benefit ratio. For instance, the Australian College of Ophthalmologists has issued a policy relating to laser surgery to correct myopia "... with low and acceptable rates of complications." ⁶ A further study on endarterectomies stated that, "On average, the immediate risk of surgery was worth trading off against the long-term risk of stroke without surgery (but only) when the stenosis was greater than about 80% diameter..." ⁷ Currently, there is a greater move towards "informed consent" so that such risk factors are understood by patients.

White defines apoplexy as brain damage where there is "... an acute neurological deficit resulting in death, or lasting more than 24 hours and classified by a physician as a stroke." ⁸

In his literature search, Terrett found that historically, the first adverse accident related to bone-setting was recorded in 1871 — almost a quarter century before chiropractic was founded in 1895. The first vascular accident following manipulation was reported in 1934 — almost 40 years after our profession was founded. ⁹

It has been estimated that the incidence of apoplexy in Australia is likely to rise by 70% in the next twenty years, due to the ageing of the population.¹⁰ The relative prevalence of such incidents is further exemplified by the indication that "everyone had some degree of stroke risk." ¹⁰ This statement is reflected later in this paper, citing Myler, who calculated that the rate of fatal cerebrovascular accidents (CVAs) in the general population is greater than that of manipulated patients.¹¹

Concern at the serious nature of CVAs should also be tempered by the knowledge that a significant proportion of those who experience an adverse reaction to spinal manipulative therapy (SMT) undergo complete or partial recovery,¹² similar to those who experience vertebral artery dissection (VAD) due to other causes. ^13-15

This paper also compares the mortality rates of nonsteroidal anti-inflammatories (NSAIDs) and other medical procedures with SMT. The relative incidence rates show SMT to be considerably more favourable than NSAIDs from a safety viewpoint. ¹⁶

To castigate or reject spinal manipulative therapy as inappropriate or comparatively dangerous is not only unwarranted, but conveniently overlooks the morbidity and mortality rates of other interventions. Such concern would seem out of proportion to that involved with everyday articular release of an intervertebral facet fixation — a vertebral manipulation.

Concern over, and considerations of, spinal manipulation does, however, also serve to emphasise the potential for positive integrated influences associated with important neurological and vascular elements within the dysfunction of dynamic vertebral segments — the vertebral subluxation complex.


METHOD

This paper was compiled from a number of sources as ongoing research over some years. These sources included reference lists, Index Medicus, manual searches and computer searches as well as news items. The network of citations obtained led to further searches. As this paper was being prepared for submission, relevant papers continued to appear in the literature. It was necessary ¹⁰ "draw the line," so these further references had to be omitted.

Information thus gleaned was collated and reviewed in an attempt to assess a comparative risk of CVAs attributed to SMT. A contrast of morbidity and mortality rates of other medical procedures and health conditions has been considered as a means of illustrating the risk factor of various therapeutic procedures and interventions.

To gain a more accurate perspective of the claimed adverse events attributed to chiropractic, a comparison has been made of the apparent high rate of adverse events of some medical procedures with the apparent low rate of adverse events involving spinal manipulation.

As a further perspective, the incidence rates of CVAs associated with everyday events are also noted.

Table 1

In Adobe Acrobat Format (201 KB)

INCIDENCE RATES OF CEREBROVASCULAR ACCIDENTS ASSOCIATED WITH SPINAL MANIPULATIVE THERAPY
YEAR	AUTHORS	INCIDENCE
1963	Cyriax 17	1: 1 0,000,000
1968	Livingstone 18	"Few" in "possibly 75,000,000" p.a.
1972	Maigne 19	1 :" "Several tens of millions"
1980	Jaskoviak 20	(over 15 yr) 0:5,000,000
1981	Hosek et al. 12	1:1,000,000
1983	Gutman 12, 21	1 :400,000
1985	Dvorak & Orelli 12, 21	2-3:1,000,000
1991	Patjin 16	1 :518,000
1992	Shekelle 22	1:100,000,000 (cauda equina/lumbar manipulations)
1993	Carey 23	1:3,846,153
1993	Haldeman 16	1-2: 1,000,000
1994	Haynes 24	1:100,000 (N.B.: This statistic applies to the ratio per patient, not per visit)
1995	Carlini 16	1 :500,000
1996	Lauretti 25	1 :2,000,000 (National Chiropractic Mutual Insurance Company per cervical manipulation)
1996	Lauretti 26	1:1,000,000 (1 neurological complication per 1 million patient visits)

* Manipulation-related mortality rate averaged for all professions is 1 in 2 years, 34 over 61 years, worldwide. ²¹

** Spinal Mobilization: In 1993, the physiotherapist Michaeli reported a "...similarity in the nature and prevalence of complications following cervical mobilisation and manipulation..." In some instances the reported incidence rate of adverse effects was higher for mobilisation than manipulation. ²⁷


LIMITATIONS OF THIS REVIEW

A review such as this is limited in the consideration of such factors as the patient's age and underlying health status, frequency of the procedure involved, necessity for a particular procedure, and available options to a particular procedure against the benefit/outcome.

Consideration has been given to the following:

• Some of the references are not recent, however it has been noticed that morbidity and mortality rates in many medical procedures have altered little in 20-30 years.





• While it is difficult to draw direct comparisons on a topic such as this, the inference from published medical papers is that SMT has a high incidence rate — presumably compared to medical care and procedures. In researching this topic it appeared that there were more papers published on the side effects of medical procedures than on the prevention of such side effects.





• While it may be argued that medicine is involved with more serious conditions, this paper is an attempt to portray certain perspectives only. It is relevant to compare one procedure with another to be able to rate its risk in perspective — to know where it stands in the overall picture.





• Consideration was also given to various forms of CVA and the sites of CVA lesions. Rather than differentiate these, it was decided to conduct a general overview at this stage.

It could be argued that in relation to SMT, incidence figures relate only to published reports, however the same can also be said for the incidence rates involving all professions, as not all adverse side effects are necessarily recorded in the literature.


REVIEW

The incidence rate of serious neurological compromise associated with manipulation is remarkably low in itself. Estimates range from as low as 1:10 million ¹⁷ (See Table_1). The incidence rate gains an even lower perspective when comparisons are made with other medical procedures, and when considered in light of incidents associated with some everyday circumstances (See other tables). In relation to SMT, it is rare that a serious side effect occurs. ^{16, 28, 29} A significant proportion of these appear to be of minor severity and transient in nature. ^{28, 30}

Michaeli also states that "The vast majority of these 'accidents' (CVAs) are of a transient nature and therefore may not have been worthy of mention in the literature." ³¹

Assendelft et al. found that of the 165 patients with associated side effects of spinal manipulation, 44 (26.7%) made a complete recovery following the initial onset and that "serious complications (are) generally considered to be low." This study included both cervical and lumbar complications. Some 49% of the lumbar complications occurred during manipulation under anaesthesia (MUA). MUA is not a customary chiropractic procedure. ²⁸

On the positive side, clinical observations of the beneficial influence of spinal manipulation on neurological function have already been noted. Carrick reported that certain procedures, including manipulative techniques, can provide remarkably promising responses in assisting some patients in degrees of recovery from central nervous system (CNS) lesions, including some forms of stroke, coma, and movement disorders such as Parkinson's disease and Friedrich's ataxia. ³³

Perspectives on CVAs

SMT Patients vs. General Population

Rather than being contraindicated in CNS conditions, Carrick's work would suggest that the association of cervical spine adjustments upon the brain and spinal cord would, in fact appear to be a non-invasive, non-drug, potent health procedure by which to positively influence neural physiology. ³³

Myler calculated that, given the statistical facts, it is less likely for a chiropractic patient to experience a fatal vertebral artery injury than it is for a person within the general population to experience a fatal stroke. He compared the rate of CVAs in the general population with that of chiropractic patients in the U.S. ¹¹ "Stroke is the third leading cause of death in the United States." ³⁴

Although there are no recorded deaths from chiropractic SMT in Australia, Myler has calculated the rate of fatal vertebral artery injury after cervical manipulation in the U.S. at 0.00025% (1 :400,000), while the rate of deaths from CVA in the general population was 0.00057% (1 : 176,900) — more than double the rate of manipulated patients. ¹¹ While there may well be other factors, such as age, type of apoplexy and healthier patients attending chiropractors, his findings are still an indication of the extremely low rate of CVA incidents in chiropractic practices.

Myler's stated rate of 1:400,000 fatal SMT-related CVAs would seem conservative. In Australia, if 3,000 chiropractors administered just 100 cervical spinal adjustments each week for 50 weeks, the procedure would have been carried out 15,000,000 times a year, making a total of 75,000,000 cervical manipulative procedures in five years, with no recorded deaths due to chiropractic manipulation. These figures are more in line with Carey's Canadian study in 1993, which found no fatalities in 50 million chiropractic manipulations. ²³   (See also Table_1).


SMT Patients vs. Patients Prescribed NSAIDs

In their paper comparing CVA risk between SMT and nonsteroidal anti-inflammatory drugs (NSAlDs), Dabbs and Lauretti found that NSAlDs have a risk factor four hundred times greater than spinal manipulative therapy. They found that the rate of death from gastrointestinal bleeding caused by NSAIDS (including bleeding from abdominal ulcers) was 0.04% — 160 times greater than neck manipulation at 0.00025% (i.e., 1:2,500 vs. 1:400,000). By comparison, the risk of a non-fatal arterial injury from manipulation was calculated as 0.001 % (1:100,000), and from NSAIDS, 0.4% (1 :250) — also a difference of 400 times. ¹⁶

In Australia in 1992, it was stated that there were some 200 deaths alone from the use of NSAIDs. ³⁵ Six years later, a more recent estimate stated, "there would be hundreds of deaths a year from side-effects of the drugs (NSAIDs )." ³⁶



General Incidence of Apoplexy and TIAs

Each year some 37,000 Australians suffer a stroke — that is more than 100 every day (1:514 = 0.195%). Of these patients, 12,000 die (1:1,583 = .063%), while another 12,000 are permanently disabled. ³⁷ Another study revealed a mortality rate of 70 per 100,000 population (1:1,429 or 13,300 p.a.). ³⁸ Some 20% of stroke patients (7,400) have diabetes, which can be a predisposing factor. ³⁶

Each day, some 25 Australians experience a transient ischaemic attack (TIA). ³⁹ Based on a population of 19 million, this is a daily rate of one in 760,000 people (.00013%), and an annual rate of 9,125 patients or 1:2,082 (0.05%) (See Table_2).

Hart stated that in the U.S., "between 0.5 and 2.5 cases per year (of vertebral artery dissection [VAD]) are reported from large referral-based hospitals." ⁴⁰ In pointing out that dissection may occur at any point in the course of the vertebral artery, he notes three categories: spontaneous, traumatic and "minor, non-penetrating trauma/neck torsion positioned somewhere in between." This infers that any SMT-related VAD could only be a portion of the 0.5-2.5 cases reported by these hospitals annually. Hart also noted that the course of the condition of most patients stabilises within one to two weeks.


Insidious and Spontaneous Apoplexy

In cases of CVA, pre-existing risk factors such as inherent arterial weakness, are not always identifiable, hence the designation, "spontaneous CVA." ^{9, 13, 40-46} The cost and risk of conclusive screening for such conditions would seem prohibitive if not impracticable, and conducting such investigations may involve further risk. The insidious nature of these unrecognisable conditions poses a significant underlying risk if they are present, however incidents seem to be extremely rare ^{16, 18, 29}   (See Table_1).

Table 2

In Adobe Acrobat Format (113 KB)

INCIDENCE OF CEREBROVASCULAR ACCIDENTS
	MORBIDITY		MORTALITY
	RATIO	%	RATIO	%
General population 11*			1:176,900	0.00057
General population 36*	1:514	0.195	1:1,583	0.063
General population 37*			1:1 ,426	0.07
NSAIDs 16	1:250	0.4	1:2,500	0.04
TIAs (daily) 38			1:760,000	0.00013
TIAs (annually) 38			1 :2,082	0.05
Chiropractic/SMT 11, 16	1:100,000	0.001	1:400,000	.00025
Chiropractic/SMT 23	1:3,840,153	0.000035	Nil:50,000,000	———
Estimated in this paper			Nil:75,000,000

* The 1000+ fold discrepancy in these figures cannot be explained.


The more insidious predisposing factors in CVAs include such conditions as asymptomatic congenital arterial weakness, ⁴⁷ obscure weakness due to previous trauma, ^{41, 42, 47} unforeseen congenital arterial anomalies, ^{14, 48-51} and anomalous cervical muscle structure. ^51-54

Due to the prevalence of previous trauma in daily life, especially motor vehicle accidents, one could expect resultant arterial weaknesses to be a common predisposing aetiological factor in spontaneous apoplexy or in incidents of apparent iatrogenesis.

At other times, identifiable conditions include recognisable signs, symptoms, anatomical anomalies, pathological and pathophysiological states. ^{49, 55, 56} These are important considerations in a therapeutic field of neurorgic influence.

The more obvious indications of risk factors can include smoking, oral contraceptives, migraines, hypertension, arteriosclerosis, diabetes mellitus, fibromuscular dysplasia, ^{11, 12, 37} as well as colitis, ^57-59 to name a few. Terrett and Sturzenegger both state that sudden and severe onset of headache and neck pain can be more immediate key symptomatic indicators. ^{55, 60}

Commenting on an unusual fatality where a player was struck by a cricket ball, an Australian coroner was reported in a 1987 newspaper article as stating that, "... it was possible that a congenital weak spot in an artery at the base of the brain had ruptured when (the patient) jerked his head. Dr Drake said everyone had such weak spots, but they might never rupture." ⁴⁷ Such an observation would suggest that some VBAs may be coincidental.

It is further reported that other seemingly innocent activities have produced similar CVAs in rather innocuous circumstances (See Table_3). These particularly include neck extension during various normal everyday procedures. ^{72 95} An interesting example of this has been reported by Goldrey as a form of "Sightseers CVA". ⁷⁵ This seems somewhat similar to the anecdotal "Golden Gate Bridge Sightseers Stroke." Such examples highlight Fogelhom and Carli's point that at times, frequent rotation and extension of the head is suspected of aggravating a weakened vertebral artery in vulnerable patients, with the onset of CVA being virtually impossible to predict. ⁶¹


Professions Associated with SMT

In 1992, Shekelle estimated that in the U.S., 94% of spinal manipulation was carried out by chiropractors, 4% by osteopaths and 2% by medical practitioners. ²² Recently De Fabio claimed that physiotherapists also conduct 2% of SMT in the U.S. ¹⁰¹

Calculations based on Terrett's 1995 study covering 58 years, however, showed that only 64.1 % of 78 manipulation-related "catastrophes "were attributed to chiropractors, while 8.97% were attributed to medical practitioners, who conduct only 2% of the manipulative procedures, and 10.26% to osteopaths, who conduct only 4% of manipulative procedures in the U.S. The balance of some 17% comprised a miscellaneous grouping. Terrett questions the reliability and accuracy of ascribing and impugning chiropractors by incorrectly attributed involvement in "all" adverse effects through the medical literature. ⁵⁴

Winterstein also noted that the proportion of chiropractor-related incidents is far less than 94% of spinal manipulation carried out by this one profession. ¹⁰²

Further extrapolation of these available figures would suggest that while conducting only 1/47 of manipulative procedures, medicine has 20.89 times, and osteopathy (2/47) has 3.92 times greater mortality rates in spinal manipulation than chiropractic.

In his 1998 study, Terrett found that in over 61 years, the practitioners reported as being associated with major manipulative side effects in 219 examined cases were actually practitioners from quite diverse backgrounds, education and training, not just from a chiropractic background, as mostly reported. The list also includes physiotherapists, osteopaths, naturopaths, a barber, masseurs, and medical practitioners (See Table_4). These major side effects comprised a total of 34 deaths worldwide over the 61 years (1: 1.8 yr). In addition, of the 185 other, more serious side effects, 44 (23.8%) either subsided or almost completely resolved with minor neurological deficits. ⁵⁴

As a comparison to the 34 deaths associated with manipulation over 61 years worldwide, Burgess reported in 1998 that there were nine reported deaths in thirteen months due to pertussis in Australia in 1997. ⁴ The pertussis deaths did not receive anything like the publicity the manipulative incidents seem to. At the monthly rate (1.44 per million), there would be 1,054.08 pertussis deaths over the same 61 year time span-a rate 3,100% higher.

By comparison, there have been three SMT-associated fatalities ever recorded in Australia — all involving medical practitioners. ¹¹²

Cyriax, the doyen of medical spinal manipulation, stated that in relation to major side effects associated with manipulation of the cervical spine, "the risk works out at about one in ten million manipulations, and provides no argument against an attempt at manipulative reduction in suitable cases." He then goes on to discuss "The danger of not manipulating." ¹⁷

Livingstone, in commenting on the "25,000 manipulators" in the U.S. in 1968, stated that there were surprisingly "few reported injuries to show for possibly 75,000,000 yearly manipulations." (This appears to be based on 3,000 per practitioner per year — 60 per week.) Livingstone does not specify whether his calculations are based on a unilateral (single), or bilateral ( double) manipulation per visit. ¹⁸

In 1993, a Canadian study by Carey estimated that of 50,000,000 neck manipulations over a five-year period, there were 13 serious YBA incidents and no deaths. ²³ This is a VBA rate of 1:3,846,153. A U.S. insurance company has estimated the serious YBA rate at 1:2,000,000. ²⁵

Table 3

In Adobe Acrobat Format (356 KB)

REPORTED ACTIVITIES INVOLVING THE CERVICAL SPINE SUSPECTED OF BEING INVOLVED WITH DISRUPTION OF CEREBRAL CIRCULATION*
Age not a factor 9	Post-operative complications of thyroidectomy 82
A bleeding nose 12, 61	Postural head changes 83, 84
Angiography 43 62	Radiographic procedure (VA angiography) 43
Archery (bow hunter) 12	Rap dancing 67-69, 85, 86
Athletics 63	Reversing a vehicle (see 'backing up')
Axial traction 64	Roller coaster 87, 88
Backing up a car 44, 62	Self manipulation 'clicked on turning' 89
Beauty parlour 65	Self manipulation (rapid) 90, 91
Birth trauma 66 (see also 'childbirth')	Sitting in a barber's chair 77
Break dancing (see also rap dancing) 67-69	Sit-up exercises 24
Calisthenics 70	Sliding head-first down a water slide 24
Childbirth 'doubtful relationship' 55	Sleeping positions 50
Contraceptive pill 13, 43	Spontaneous rupture of aneurisms 43
Coughing 71	Spontaneous turning of head 40 44
Dental procedure 44	Spontaneous vertebral artery dissection 9, 40-46
Diving into shallow water 72 (see 'falls')	Star gazing 16
During surgery 12	Stooping to pick up a bucket 24
During x-ray examination 61	Surgery, neck positioning during anaesthesia 79
Emergency resuscitation 12	Swimming 92
Falls (minor) 43	Tai chi 78
Falls causing hyperextension 43	Telephone call (cordless) 89
Fitness exercise 71	Traction of cervical spine 48, 63, 77
Football 72-74	Traction and short wave diathermy 89
'Golden Gate Bridge' syndrome (sightseeing) 75	Trampoline 40
Gymnastics 70	Trauma 94
Hair dressing 76	Turning one's head 83
Hanging out washing 77	Turning one's head while driving 44 95
Head banging 43	Under anaesthesia 12
Motor vehicle accidents 44	Voluntary movement 96
Neck callisthenics (Tai chi) 78	Watching aircraft 77
Ophthalmological perimetric visual examination 79	Whiplash 72, 96
Overhead work 80	Yawning & vigorous stretching (spinal artery) 97
Painting ceiling 80, 81	Yoga ('Bridge' or 'Back push-up') 70 98
	Yoga (rotating head) 98

* Adapted from Terrett ^{9, 12, 54, 55}

[Of tangential interest, Berger and Sheremata ⁹⁹ observed persistent neurological deficits in suspected multiple sclerosis patients; the signs were precipitated by a hot bath, They found that other aggravating factors indicating this predisposition to acute exacerbation of signs included a lovers' quarrel and golf. The reliability of the 'Hot Bath Test' was challenged by Davis. ¹⁰⁰]

Table 4

REPORTED MANIPULATIVE SIDE EFFECTS ASSOCIATED WITH A VARIETY OF OTHER PRACTITIONERS FROM DIVERSE BACKGROUNDS *

Physiotherapists 24 30, 31, 81, 103, 104 Osteopaths 77, 105-107 Masseurs 54 Naturopaths 54 Medical practitioners 24 54 Kinesiotherapist 108 A barber 54 A kung-fu practitioner 54 A patient's own wife 109 Self manipulation 90 110 Unqualified practitioners designated to be 'chiropractors' without formal chiropractic education 11

* Adapted from Terrett 54, ⁵⁵



Adverse Effects from Medical Procedures

There are morbidity and mortality incidents with most prescription and non-prescription drugs, as well as with major and minor surgical procedures. Generally, these adverse events are far higher than manipulative procedures. The mortality and morbidity rates of certain medical procedures can be viewed to gain a perspective on the risks involved ^113-116   (See Tables   5,   6,   7).

It would be grossly irresponsible and misleading if patients were led to believe that adverse effects from medical procedures did not exist, or were disproportionately low. It is surprising how patients seem to accept the incidence of risks and complications from medical procedures as "normal," yet still be alarmed at the limited possibility and significantly lower adverse incident rates ("negligible" ²⁴) involving manipulative procedures in chiropractic or other professions using manipulation. Unwarranted sensationalism of cases involving chiropractors threatens to create an impression out of proportion to the actual facts. One wonders what would happen if all medical procedures were subject to the same levels of safety, efficacy, journalistic scrutiny and particularly inaccurate publicity.

Issues concerning the efficacy of medical care have already been raised in such respected journals as the Lancet, British Medical Journal, the Journal of the American Medical Association and the Medical Journal of Australia. Such controversial issues do not appear to have received general media exposure or public discussion to any great degree. ^{125, 172-177}


What should be of serious concern, however, is the statement in one of the world's most respected journals in 1991, the British Medical Journal:

"... only about 15% of medical interventions are supported by solid scientific evidence..." and "only 1 % of the articles in medical journals are scientifically sound and partly because many treatments have never been assessed at all. ¹⁷⁴

Six years earlier, in 1985, medicine was already aware of the problem when Leeder wrote in the Medical Journal of Australia:

"Much medical practice has escaped critical appraisal...many treatment schedules, new and old, simple and complex, have been adopted and endorsed without firm evidence that they achieve more good than harm... (or) have never been satisfactorily evaluated... Some procedures … became entrenched in professional mythology long ago (and) have remained unchallenged despite their appalling cost in terms of human suffering." ¹⁷⁵

In 1998, Moore and colleagues noted two drugs which were shown to have serious and potentially lethal cardiac side effects. They had been on the market for twelve and fourteen years, respectively. They stated:

"Discovering new dangers of drugs after marketing is common. Over 51 % of approved drugs have serious adverse effects not detected prior to approval. Merely discovering adverse effects is not by itself sufficient to protect the public." ¹⁷⁶

The International Classification of Diseases code ¹⁷⁸ lists the following iatrogenic classifications which include numerous headings under "misadventure" and "complications":

E850-858 - Accidental poisoning and medication errors.

E870-879 - Misadventures during surgical and medical care.

E930-949 - Drugs causing adverse effects in therapeutic use.

E977.9 - Medicine poisoning by overdose- wrong substance given or taken in error.

E995.2 - Adverse effect, correct substance properly administered.

Adverse drug reactions rank as the fifth ("between fourth and sixth") leading cause of death in the U.S. — 106,000 deaths in 1994. ¹²⁵


In relation to medical complications, a 1982 study by Steel et al. found"... a 36% incidence of iatrogenic illnesses among 815 consecutively selected patients in a tertiary care university hospital." In 2% (16.3 of those admitted), " … these complications were believed to have contributed to death." ¹¹⁴ By 1998, Lazarou and colleagues found that there was virtually no change in the incidence rate of adverse drug reactions in the 32 years of their study. ¹²⁵

A two-year study by Rankin et al. (1990-1992) found that in Australia, "Between 170 and 850 (1-5%) strokes occur (annually as) a major iatrogenic complication of cardiopulmonary by-pass surgery." ¹⁷⁹ Other major surgical procedures also carry the risk of stroke (See Tables 8 ).

In 1993, Nachemson stated that in relation to spinal surgery, "... the clinical studies have largely lacked validity: controlled, prospective tr1als are disappointingly rare." ¹⁸²

These issues alone should_overshadow and create more concern than political medicine's preoccupation with otherprofessions which it may see as competitors.

While medicine seems interested in highlighting incidents involving spinal manipulation, it can be questioned as to whether patients are fully cognisant of the high rates of medical incidents. This is not intended as a criticism, but more to place the rate of incidents in context. One cannot ignore the assumption of "acceptable statistics" in the absence of public awareness.

Table 5

In Adobe Acrobat Format (348 KB)

MORTALITY RATES OF VARIOUS MEDICAL PROCEDURES AND DAILY EVENTS*
SURGERY	MORTALITY
Appendectomies	1:74 5
Cervical spine surgery	1:145 5
Cholecystectomy	1:51-200 5 116
Colon surgery	1:14-50 5
Coronary bypass surgery (up to 21 % of patients who experienced an adverse event resulted in a fatal outcome)	1:263 34
Herniated disc surgery	1:481 117
Iatrogenic cardiac arrests	1:1.7 118
Iatrogenic esophageal perforations	1:3.5 119
Lumbar discectomy	.9:1000 120
Lumbar fusion	1:50-1400 111
Lumbar laminectomies	1:204 5
Lumbar surgery	1:683 121
Lumbar 'procedures'	1:1,430 122
Percutaneous transluminal angioplasty Intracranial 16.7% mortality	1:6 123
Sciatic surgery	1:684 121
Small intestine surgery	1:4.76 5
DRUGS
Drug reactions	1:230 124 1:14.9 125
Hospital deaths	1:28 124 1:312.5 125 1:67 126 1:2.86 127 1:1103 128
Drug related problems (DRPs) (1/3 'not preventable')	1:29 129
Adverse drug reaction (17.2%)	1:5.8 129
Taking a drug for which there was no valid medical indication	1:5.8 129
Non-compliance (50%)	1:2 129
Medication error (out-patients) 1993	1:131 130
(in-patients) 1993	1:854 130
Anti-inflammatories	1 :63,333*
HOSPITAL ADMISSIONS
Iatrogenic paediatric admissions to intensive care	1:27 131
Iatrogenic adult intensive care admissions	1:41 132
Hospital iatrogenesis - 50,000-100,000 deaths due to pulmonary embolism in hospitalised patients annually in the US 133	1:50 114
RADIOLOGY
Nuclear bone scan	1:3,000 134
MEDICAL PROCEDURES
Venipuncture	1:25,000 1
Spinal manipulation	See Table_1
DISEASES/CONDITIONS
Ischaemic heart disease	162:100,000 1:617 38
Cerebrovascular disease	70:100,000 1:1,429 38
Cerebrovascular disease ('age adjusted') 135 (of population, not mortality rate of cases) 1988
Males	USA   1:1,739
	Australia   1:1.226
	Greece   1:751
Females	USA   1:1,984
	Australia   1:1,355
	Greece   1:725
Cerebrovascular disease (Australia) 135
Males	1954   1:689
	1993   1:1,471
Females	1954   1:593
	1993   1:1,653
	1996 37   1:1,429
Coronary heart disease ('age adjusted') 1983 135
Males	Japan   1:1,873
	Australia   1:366
	Scotland   1:254
Females	Japan   1:3,247
	Australia   1:707
	Scotland   1:511
CHRONIC DISEASES 1993 (Australia) 136 (per population, not morality rate of cases)
Coronary heart disease	1:624 136
Ischaemic heart disease 1996	1:617 135
Chronic obstructive airways disease 1996	1 :525(est) 135
Stroke	1:1,536 136
All cancers	1:555 136 1:704 135 1996
Cancer - upper respiratory	1:2,833 136 1:526 136 1996
Melanoma	1:21,277 136
Prostate cancer	1:2,841 136 1:7,143 (est.) 135 1996
Breast cancer	1:3,718 136 1:7,143 135 1996
Colorectal cancer     Incidence rate males 1996 Incidence rate females 1996	1:4,098 136 1:4,348 135 1996   1:17 137 1:27 137
Asthma	1 :23,256 136
Diabetes	1:7,143 136
HIV	1:1,770 136
RELATIVE RISKS DAILY CIRCUMSTANCES/SPORT/INDUSTRY
Motor vehicle accidents	1:9,091 111 1996
Lightning strike	1 :200,000 138 (Hit by) 1 :600,000 111 Deaths 1 :2,000,00o 139
Homicide	1 :52,632 136
Acting in theatre	Injury 1:2.2 140
National workplace fatalities (Australia) 141 (597 deaths per year per no. of employees)
Forestry and logging	1:1,075
Fishing and hunting	1:1,163
Mining	1:2,778
Transport & storage	1:4,348
Agriculture	1:5,000
Construction	1:10,000
Rugby Union (participants)	1:5,000 139
Spinal cord injuries	1:6,250 142
Rugby Union	1:18,868 143
Rugby League	1 :55,556 143
Neurological deficits	1:16,667 142
Fatalities	1:15,000 139
Boxing fatalities (per contest)	1:10,000 144

* Estimation is based on 200 deaths each year in Australian population aione-all citizens including those not taking NSAIDs = 200:19,000,000. ³⁵A more recent estimate Is based on '10%' of the 4,500 NSAID-related upper gastrointestinal hospital admissions annually-between 200 and 400 deaths per annum. ¹⁴⁵ Blower estimates that NSAIDs could be responsible for 3,000 deaths in Great Britain. ¹⁴⁶

Table 6

In Adobe Acrobat Format (250 KB)

MORBIDITY RATES
ANAESTHESIA
General anaesthesia	1:1,103 174
Anaphylactoid anaesthetic reactions (restricted to life-threatening or operation-disrupting)	1:1,000to 1:10,000 148
SURGERY
Atherosclerotic procedure-related complications	1 :6 123
Idiopathic scoliosis surgery (adult)	1 :2.44 minor 149 1 :4.4 serious
Cardiac surgery	1:1.64 (51%) 150
Chemonucleolysis 121 Cauda equina New root deficits Paraplegia Allergic reaction to anaesthesia	1:2,911 1:257 1:21,831 1:49
Discectomy Cauda equina	1 :27 120 1 :200 120
Sciatic surgery 'Wrong level' Total complications	1:45 121 1:4
Lumbar disc re-operation Successful (28%)	1:3.6 151
Repeat surgery for failed lumbar disc surgery Percentage successful result of repeat: Discotomy Decompression Stabilisation Decompression & stabilisation Repair of pseudoarthrosis & decompression	1:5.6 152 75.0% 27.8% 33.0% 50.0% 14.3%
DRUGS
Drug reactions Daily use of aspirin 6% more likely to experience a stroke 111 25% of all reported drug reactions in the UK are associated with NSAIDs, yet they comprise 5% of prescriptions. 153	1.67 147
MEDICAL
Venipuncture	1 :25,000 1
Epidural (Depo-Medrol)	1:40 - 1 :200 148
HOSPITAL
Hospital iatrogenesis 18%-30% of all hospitalised patients have a drug reaction...resulting in doubling of hospital duration. 115	1:2.78 114
Iatrogenic paediatric admissions to intensive care Drug complications Surgical complication	1.22 131 1.68 1:77
Iatrogenic adult admissions to intensive care Drug complications Therapeutic error Drug reactions (30% of these have a second drug reaction)	1 :7.9 132 1:14 1:23 1:20-1:33 115
DISEASES/CONDITIONS — INCIDENCE 156
Measles Pneumonia Encephalitis Measles-encephalitis-mortality Brain damage	1.25 1:2,000 1 :20,000 1:5,000
Breast cancer by age 70 After 5 or more years on HRT	1 :14 157 1:10 157
VACCINATION
Diphtheria/Tetanus/Whole cell pertussis Anaphylactic reaction Severe reaction	1 :50,000 4 1:2,000 4
Measles---€ncephalitis (expected recovery)	1:1,000,000 4
SPINAL MANIPULATION
VBA (non-fatal) - 'as low as'	1: 1,000,000 64
SMT-related cauda equina syndrome	1:100,000,000 22

It is noted that while some of these intetentions do not necessarily compare directly with manipulative therapies, they reflect the risk factors which exist with all procedures.

Table 7

In Adobe Acrobat Format (222 KB)

MORTALITY AND MORBIDITY RATES OF OTHER MEDICAL PROCEDURES*
	MORTALITY	MORBIDITY
Cervical manipulation
@ 1 :400,000 major		0.00025% 11
@ 1 :40,000 minor		0.0025% 49
Estimate only	0.000000096%**
General population (VBA-related deaths)	0.00057% 11
General surgery (30-day mortality #)	5.6% 113
Orthopaedic surgery#	1.8% 113
All surgery#	1.2% - 5.4% 113
After adjustment for risk factors #	0.49% -1.53% 113
Total hip replacement	1.1 % 158
Peripheral vascular surgery	4.6% 113
Otolaryngology surgery	2.9% 113
Iatrogenic hospital admissions	1.84%	36.0% 114
Vaccination at wrong body location		33% 159
Medication error (out-patients 1:131)		.76% 130
Misinterpretation of medical jargon in laboratory reports		80% 160
Epidural anaesthesia		1.6% 161
Hospital medication: Over-prescribed/ or never used		16-20% 162
NSAIDs		0.04% 16

Liposuction (US) — 100 deaths in the past 12 months ¹⁶³

Adverse effects associated with traction, ¹⁶⁴ ultrasound, ¹⁶⁷ acupuncture, ¹⁶⁸ intrathecal steroid injections, ¹⁶⁷ and vaccination ^{4 170-172} have all been reported.

--------------------------------------------------------------------------------------------------

* Adapted from Khuri et al.
** Based on an approximate calculation as follows:
1 00,000 man_worldwide—all professions
X 100 average cervical manipulations per week (e.g. 2 procedures/patient visit, 50 patient visits/wk)
= 10,000,000 cervical manipulations/wk
= 520,000,000 per year
@ .5 deaths per year (See Table_1)
= mortality rate of 1:1,040,000,000 = 0.000000096%

Table 8

In Adobe Acrobat Format (106 KB)

INCIDENCE OF STROKE ASSOCIATED WITH MEDICAL PROCEDURES
Australian population Deaths from stroke	1:1,639 180
Non-stroke comparisons 180
Cancer	1:565
Suicide 15-24 yr/age	1 :4,000
Heart disease	1:690
Motor vehicle accidents	1 :3,125
Cardiopulmonary by-pass surgery	1-5:100 179
Open-heart surgery	0.3% - 5.2% 181
Coronary by-pass surgery	6.1% 34
Percutaneous transluminal angioplasty 123
Intracranial
Stroke	33.3%
TIA	22.2%
Mortality	16.7%
Extracranial (supraorbital)
Stroke	1%
TIA	2%
Restenosis	5.9%

DISCUSSION

It is always a most unfortunate event for any patient to suffer any side effect from any procedure or accident, regardless of which profession is concerned. One cannot help but feel empathy, regret and sadness for any involved patient and their family. However, the degree of inherent risk associated with all health interventions is distinct from professional negligence, which is unacceptable.

Due to the lack of "bias" ^{28, 183} or partiality of discussions raised on the issue of CVAs as a result of manipulation, it may be reasonable to assume that by now most patients would be aware of the possible risks associated with manipulative procedures.

The chiropractic profession is at the forefront in recognising the possible complications associated with SMT; similar awareness should apply to all procedures. The established manipulative professions would seem to be qualified to recognise and minimise the risk to potentially vulnerable patients exhibiting signs and/or symptoms. Various studies on the topic have been published; these have been collated recently by Terrett, who has published extensively on the subject. ⁵⁵

The chiropractic profession actively seeks to keep practitioners aware of all aspects of risks. As well as informative seminars and journal papers, chiropractors' basic training prepares them for preventive iatrogenic considerations. This includes careful case history taking, learning pre-manipulative testing and appropriate manipulative skills in the serious area of possible iatrogenic complications.

The chiropractic profession was recognised in a 1979 New Zealand government study as being the profession best qualified to carry out spinal manipulative procedures. This independent study also found that "Spinal manual therapy in the hands of a registered chiropractor is safe." ¹⁸⁴

It is quite irresponsible for medicine to condemn spinal manipulation when the potential for incidents is, by its own standards, extremely rare. Even diagnostic investigations have a risk/benefit ratio. ^{39 114 134} The double standard is evident when in fact generally, drugs and surgical procedures have risks of side effects with a significantly higher fatality rate than spinal manipulation. It has been stated that "... all medications, even so-called natural, can cause adverse reactions." ¹⁸⁵

Because of medicine's self-serving publicity about SMT, discerning patients may see through what appears to be the charade of biased scaremongering. Nevertheless, the demand for qualified manipulative care continues to expand. A significant proportion of the population — almost 50% ¹⁸⁶ of patients — actively seek an appropriate alternative approach to their health problems. One must assume this option is exercised either as a preference, a search for results, or choosing not to accede to chemical or surgical intervention.

In 1998, Wilks expressed surprise at the limited exposure of a 1987 American federal court finding that the American Medical Association "... was dishonest, untrustworthy (and) not objectively reasonable" when it acted to neutralise the competition and influence of chiropractic on the health care scene. ¹⁸⁷The referenced literature and media similarly appear to have been noticeably reticent on this particular issue of a single profession's (medicine's) domination of the entire health field. Strangely the media, and society in general, do not appear to want to seriously question medical philosophy, paradigm, monopolisation, efficacy, costs or procedures. ¹⁸⁸

Medicine has adopted terms suggesting procedures have an "acceptable risk." These include "risk-adjusted mortality rates," "net clinical benefit" and "risk/benefit ratio," yet there seems a reluctance to concede the application of these terms to procedures outside the medical profession. ¹⁷²It seems that at times "such rates have been condoned" — at least in relation to dural puncture, ¹⁸⁹ or in immunisation programs where "the benefits of preventing the disease far outweigh the risks of vaccination." ¹⁷²


Lack of Government Standards or Guidelines

Regardless of the low rate of incidents in the manipulative sciences, the material reviewed warrants advocacy of further caution and awareness, with continued endeavours towards risk elimination. It is fundamental for the manipulative professions to maintain the maximum available level of recognised safety, training and education before employing their conservative manipulative procedures. ¹⁹⁰

As mentioned, although some SMT-related accidents may be unforeseen,^{28, 61, 191} for the vast majority there are procedures for both recognising and determining patients at risk. Essential education has been established for this purpose.

Despite the importance of public interest in standards of care, the Australian state legislatures have created a distinct anomaly through standardisation and mutual recognition of registration acts for health professions. For instance, the Victorian government's Chiropractors Registration Act and the Osteopathic Registration Act have, through an implication by considered omission, sought no standards or requirements placed upon unregistered practitioners who attempt spinal manipulation. ¹⁹²That is, any person in Victoria may carry out neck manipulation so long as he does not present himself as a chiropractor, osteopath, physiotherapist or medical practitioner.

Australian state governments do not require minimal training standards for the manipulative procedures utilised by non-registered practitioners — only for registered manipulative professionals who specialise in the field. This also allows medical practitioners to attempt to manipulate the spine, even if they have no training whatsoever in the procedures. This would seem incongruous when "protection of the public" and "standards" were two of the primary criteria for establishing registration for the manipulative professions in the first place, as would seem to be the case with all health professions. ^193-195

Such a fundamental safeguard would seem even more important in health care where primary contact care practitioners are responsible for the diagnosis as well as the safe and effective management of patients' welfare and health problems. As has been indicated earlier, practitioners not formally trained or qualified in SMT have been associated with incidents of CVAs ^{54 111} (See Table_4).


The kind of legislative policy that currently exists would tend to support the questionable assertion that practitioners need not be qualified to render SMT, that there is relatively little concern for any danger from any SMT side-effects, or indeed, that there is any perceived danger at all.



SUMMARY

While there are some stated limitations to this type of review, a number of matters were discussed in attempting identify related issues:

• The rate of adverse effects, namely cerebrovascular accidents related to spinal manipulative therapy, was shown to be extraordinarily low in the overall health care scene.





• The rate of SMT-related CVAs associated with the chiropractic profession is lower than for osteopathy and medicine. Figures could not be determined for physiotherapy.





• In general terms, the rate of SMT-related CVA is also lower than the rate of strokes in the general population.





• Morbidity and mortality rate of SMT is far lower than that suffered by patients taking NSAIDs.





• There are both identifiable and unidentifiable anomalies, weaknesses, diseased states and conditions which can influence the incidence of apoplexy in society.





• There is a significant percentage of spontaneous apoplexy in the general population, and therefore, at times, such a high "natural" frequency could be confused as an SMT-related incident.





• The rate of preventable drug- and surgery-related iatrogenic illness in medicine is generally far higher than for SMT, demonstrating SMT to be a safe and conservative form of intervention by comparison.





• The rate of vertebrobasilar accidents associated with manipulation has been grossly exaggerated, inaccurate and sensationalised by some ill-informed sources.





• SMT in the hands of a practitioner properly qualified in this specialty is shown to be a particularly safe procedure.





• There appear to be medico-political overtones to the subject of SMT-related iatrogenesis.

CONCLUSIONS

This paper has attempted to identify perspectives of iatrogenesis and contrast levels of morbidity and mortality with a number of elements which may adversely affect health. In drawing such comparisons, it is worthwhile to understand where SMT is situated in relation to complications related to other forms of intervention.

It is incumbent upon practitioners of all professions to be aware of the risks involved in every type of procedure. Patients are also entitled to accurate information about the procedures that may be utilised in the course of their care. Not only do practitioners have a role in providing this information, but the scientific literature, as well as the printed and electronic popular media who report any adverse incidents must be responsible and accurate in this duty.

This review of the evidence has indicated that a potential risk of catastrophic side-effects from SMT is substantially less than for any of the medical procedures or interventions listed in the tables accompanying this paper.

It is submitted that as reflected in the demand for therapy, spinal manipulation has contributed significantly to the health and well-being of much of the world's population. Unsubstantiated published opinions and so-called scientific distortions of the facts are irresponsible. There are no "double-blind controlled scientific studies" which reject a reasonable degree of efficacy of spinal manipulation for appropriate mechanical back and neck conditions — indeed, quite the opposite. ^196-199

In conducting this study it has been shown that the distorted impression of risk associated with cervical spinal manipulation should be cast in the proper and minimal perspective which is its due. It would be hoped that any reservations which dissuade qualified practitioners from utilising cervical spinal manipulation in appropriate situations, or dissuades patients from accepting and subsequently benefiting from such techniques, would be mitigated, and the rationale for the therapy better understood.

If medicine is to assume a scientific role, it must also record accurately, fairly and without prejudice on such scientific matters concerning health and welfare. In this author's opinion, it is demonstrably wrong and scurrilous to portray SMT as a highly dangerous procedure — both in its own right, and in light of the facts concerning other procedures. It is both a judicious and propitious procedure which is safe by comparison and may perhaps explain medicine's increasing interest in adopting SMT as one of its own regimes.

As inferred by Assendelft et al., ²⁸ it is up to the properly informed patient and practitioner to compare the risk/benefit ratio in choosing to seek relief through a particular type of intervention. To this end, conservative procedures like spinal manipulation would appear to have a distinct advantage due to there inherently low risk.

Without wishing to diminish the importance and serious nature of cardiovascular incidents related to SMT, and with due recognition for continued caution for its potential, the miniscule risk which may be associated with SMT is extraordinarily low and should be encouraged and endorsed as a safe front-line health procedure.

It has been suggested here that there is a relatively high incidence of CVA in the general population, that there can be a number of predisposing conditions related to CVAs, that spontaneous CVAs are relatively common, and that there can be a number of common activities associated with CVAs.

The professions who utilise spinal manipulation must strive for continued minimisation of possible SMT-related side effects — indeed, their elimination — but the facts and statistics presented here suggest that given the nature of its considered neural influence, and with all the information in perspective, spinal manipulation in the hands of an appropriately qualified professional is both conservative and one of the safest therapeutic procedures.


ACKNOWLEDGEMENT

The author gratefully appreciates the assistance provided by Dr Damon Willmore for his input and assistance in the preparation of this paper.

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