Neck pain is a debilitating and all too common issue worldwide. According to a systematic review published by Cote et al, the annual prevalence of neck pain in Quebec City is 48%, 27% in Norway, and 34% in the UK. Subsequently, a limitation in activities of daily living was found in between 11-14% of individuals. An additionally alarming statistic is that 50% of these individuals who suffer from neck pain still have symptoms 12 months after onset. Silverstein et al looked at workers compensation claims in the state of Washington between the years of 1990 and 1998. According to their data, 40.1/10,000 full-time equivalents (FTEs) reported claims for soft-tissue neck pain. This same study found that 19.1/10,000 FTEs missed 4 or more days of work secondary to neck pain. This tells us that neck pain is anything but a ‘self limiting’ disorder, but what are we doing to treat these patients?
Treatment approaches differ between clinicians and professions, but many include various forms of exercise, pain modulation, soft-tissue mobilization, joint mobilization, and the ever controversial cervical manipulation…
Cervical manipulation is the staple of the chiropractic profession, but is also utilized by physical therapists, osteopathic physicians, and other healthcare professions. As beneficial as these manipulative techniques appear to be, they are constantly the focus of media and medical scrutiny, but is it warranted? According to Di Fabio et al, between the years of 1925 and 1997, there were 177 cases of serious injury and 32 mortalities associated with cervical spine manipulation (CSM). The most publicized and discussed adverse events come in the forms of Cervical Artery Dissection (CAD) or Vertebral Artery Dissection (VAD). Lee et al performed an epidemiological study attempting to determine the incidence and prognosis of CAD and VAD. The general incidence of VAD is only 0.97 per 100,000 and CAD was only slightly more common at 2.6 per 100,000 people. With such a low incidence, what is the general risk of causing a severe adverse event as a result of manipulation? There have been a few studies published in recent years with reported incidences of <1/5,000,000 manipulations (Jaskoviak et al), 1/50,000 (Gutmann et al), 1/383,750 (Dvorak et al), <1/518,886 (Patijn et al), 1/3,800,000 (Carey et al), and 1/200,000 (Haynes et al). In addition to these older studies, Gouveia et al conducted a systematic review of the literature from 1966 to 2007 and after review of 46 studies, they concluded the frequency of serious adverse events varied between 5 strokes/100,000 manipulations to 1.46 serious adverse events/10,000,000 manipulations and 2.68 deaths/10,000,000 manipulations. Just to clarify, these statistics do not mean that cervical manipulation CAUSED the adverse event, only that the adverse event was associated with a recent manipulation.
Common symptoms associated with VAD include headache and neck pain, so isn’t it reasonable to assume that these strokes are not caused by the aforementioned interventions, but that these patients are just more likely to seek care for their presumed musculoskeletal symptoms? Cassidy et al investigated just that hypothesis. They found that VAD in those < 45 years old was 3 times more likely when recently visiting a chiropractor OR primary care physician (PCP). In those patients > 45 years old, there was no association between a chiropractic visit and VAD, however there was an association between PCP visits and VAD. So are PCPs somehow causing their patients to have cerebrovascular events? Common sense would dictate that these associations are simply due to ‘at risk’ patients seeking help from those qualified to treat them, regardless of intervention. All this being said, could these adverse events be prevented or predicted?
In a thorough review of 134 case reports of adverse events following cervical manipulation, Puentadura et al tried to determine how many cases could have been prevented and under what circumstances the events typically occurred. Of the cases reported, chiropractors were the practitioners in 93 cases, osteopaths in 11 cases, non-clinicians in 9 cases, physical therapists in 5 cases, a naturopath in 1 case, and unknown practitioners in 15 cases. Chiropractors were involved in the vast majority of cases, but this is likely secondary to their increased utilization of CSM compared to other professions. After evaluation of each case, the investigators determined whether CSM was indicated or unnecessary and whether the event was preventable based on presence of contraindications and/or red flags. According to their data, 44.8% of cases could have been prevented had a thorough examination and history been taken. Additionally, of the 7 deaths included, 4 could have been prevented, 1 was unpreventable, and 2 were unknown (lack of adequate information within case report). At the most recent IFOMPT Conference in Quebec City, a document written by Rushton et al was created to provide a framework for pre-manipulative evaluation. The following lists are typical historical findings in those patients that should be contraindicated from manipulation or are at risk for disorders that may become worse following manipulation:
– Multi-level nerve root pathology
– Worsening neurological function
– Unremitting, severe, non-mechanical pain
– Unremitting night pain (preventing patient from falling asleep)
– Relevant recent trauma
– Upper motor neuron lesions
– Spinal cord damage
Risk Factors of CAD:
– Past history of trauma to cervical spine / cervical vessels
– History of migraine-type headache
– Hypercholesterolemia / hyperlipidemia
– Cardiac disease, vascular disease, previous cerebrovascular accident or transient ischaemic attack
– Diabetes mellitus
– Blood clotting disorders / alterations in blood properties (e.g. hyperhomocysteinemia)
– Anticoagulant therapy
– Long-term use of steroids
– History of smoking
– Recent infection
– Immediately post partum
– Trivial head or neck trauma
– Absence of a plausible mechanical explanation for the patient’s symptoms
Risk Factors of Upper Cervical Instability:
– History of trauma (e.g. whiplash, rugby neck injury)
– Throat infection
– Congenital collagenous compromise (e.g. syndromes: Down’s, Ehlers-Danlos, Grisel, Morquio)
– Inflammatory arthritides (e.g. rheumatoid arthritis, ankylosing spondylitis)
– Recent neck/head/dental surgery
Outside of the identification of contraindications and red flags through patient history and subjective interview, is there evidence to support the use of pre-manipulation physical evaluation in identifying or reducing the prevalence of adverse events? Carlesso et al conducted a survey of Member Groups and Registered Special Interest Groups within the IFOMPT trying to identify how often clinicians performed pre-manipulation Vertibrobasilar Insufficiency (VBI) testing. Of the surveys that were returned, 77% of respondents did perform pre-manipulative screening for VBI. Unfortunately, despite the prevalence of pre-manipulation physical examination, there may not be evidence to support its efficacy. According to Mitchell et al, the most provocative and reliable positional test for VBI is sustained end-range rotation. This test may be of benefit, however research is lacking regarding how predictive or how reliable this test actually is. This examination is meant to maximize the occlusion of the vertebral artery, but is this too intense for those ‘at risk’ patients? In my opinion, this test puts patients into a much more dangerous position than most manipulative techniques ever will. This test alone may stress the vertebral artery beyond its limit and may predispose patients to the condition we are attempting to screen for. In fact, a biomechanical study conducted by Herzog et al determined that vertebral artery strain was significantly higher during diagnostic and range of motion testing compared to high velocity, low amplitude cervical manipulation.
Cervical manipulation is an effective means to decrease pain and improve function in patients suffering from mechanical neck pain and, based on the current evidence, is a generally safe intervention. The incidence of adverse events is minimal and, through adequate screening and evaluation, most adverse events can be prevented. There is still an inherent risk, as 10.4% of adverse events were unpreventable (Puentadura et al), but as previously mentioned, these are only associations. Many of these cases may have simply been a case of individuals presenting with seemingly mechanical symptoms (neck pain and headache), but were truly demonstrated preliminary symptoms associated with CAD. The well-informed clinician will take into consideration the patient’s prior medical history, current symptomology, comorbid conditions, and physical examination findings prior to performing any intervention aimed at the cervical spine. Through the use of sound clinical reasoning and after taking adequate precautions, I do believe the juice is worth the squeeze and my next post will delve a little more into why.