A number of clinical prediction rules (CPR) for the use of spinal manipulation in individuals with low back or neck pain have been derived in the past 15 years. CPRs attempt to identify variables from the patient’s history and/or physical examination that may be able to predict whether that individual patient will respond favorably to a given treatment.[1-3] According to Levangie, a CPR is an “algorithm or scoring system that leads to a prognostic estimation or a diagnostic category.” At face value, the use of CPRs by physical therapists in patients with spinal pain appears “evidence-based”. In truth, CPRs are no more than a large case series; moreover, they are correctly classified as level 3 evidence on the hierarchy since they are derived, in the main, using single-arm studies without a control or comparison group.
Importantly, the overreliance on dichotomous CPRs may bias clinical reasoning and hence decision making, thereby excluding patients from a potentially beneficial intervention. The limitations associated with the use of CPRs by physical therapists have been highlighted in the literature over the past decade; therefore, the topic deserves a closer look.[1-3, 5-8] According to a systematic review that evaluated 15 separate CPRs, Stanton et al concluded, “There is, at present, little evidence that CPRs can be used to predict effects of treatment for musculoskeletal conditions.” Moreover, all 15 CPRs were evaluated using a single-arm trial design; thus, it is not possible to determine whether the CPRs identify prognosis (regardless of treatment) or specifically response to treatment (e.g. spinal manipulation). Perhaps the most debated example of this within the physical therapy community is the CPR derived by Flynn et al for the use of spinal manipulation in patients with acute low back pain.
There are three distinct phases that a CPR must pass through before it can be confidently used in the clinic by practitioners with their patients. The three phases are: (1) derivation or the development of predictors from an observational study and clinical experience, (2) validation using a two-arm trial and (3) analysis of the impact or usefulness and cost-effectiveness of the rule in various populations.[8,10] Following derivation, validation, and impact analysis, the CPR should only then be implemented into clinical practice.
Notably, the two CPRs—i.e. multi-test regimens of pain provocation tests—described by Laslett et al and Van der Wurff et al for diagnosing sacroiliac dysfunction without the use of double diagnostic injections have been successfully validated.[12,13,29] However, according to a recent systematic review that evaluated 13 diagnostic CPRs for low back pain, only 1 diagnostic CPR for identifying lumbar spinal stenosis and 2 diagnostic CPRs for identifying inflammatory back pain[15,16] have actually undergone validation.
THE 5-ITEM SPINAL MANIPULATION CPR FOR ACUTE LBP
In an independent, randomized controlled trial of 239 patients presenting to general practice clinics for LBP, Hancock et al found the Flynn et al 5-item spinal manipulation CPR to “perform no better than chance in identifying patients with acute, non-specific LBP most likely to respond to spinal manipulative therapy.” However, only 5% of the subjects in the experimental group actually received high-velocity, low amplitude thrust techniques rather than non-thrust mobilization; further, Cleland et al subsequently found the Flynn CPR is not generalizable to treatment protocols that substitute nonthrust mobilization techniques for high-velocity low-amplitude thrust manipulation techniques. Nevertheless, Learman et al reported no difference in patient outcomes with at least 4 positive tests on the 5-item Flynn CPR treated with either thrust manipulation or nonthrust mobilization. Importantly however, neither the Cleland et al nor the Learman et al study incorporated a control group—i.e. all patients in both studies were positive on the CPR—therefore; both studies are unable to determine if the use of thrust manipulation for patients who are positive on the CPR would produce superior outcomes when compared to no treatment.
Moreover, according to 5 recent systematic reviews, the Flynn et al prescriptive CPR is still confined to the development or derivation phase—i.e. it hasn’t successfully been validated nor has it passed through the clinical impact phase.[2,3,8,10,32] That is, the 2004 Childs et al “validation” study of the 2002 Flynn et al 5-item spinal manipulation CPR “is most appropriately considered a derivation study and not a validation study”. Additionally, the inter-observer reliability of the 5-item spinal manipulation CPR has yet to be investigated in any of the validation studies—i.e. to ensure consistency between examiners in the interpretation of a patients status on the rule. Nevertheless, the Flynn et al CPR is still widely taught as “gospel” within entry-level physical therapy programs, post-graduate orthopaedic residencies, and manual therapy fellowships. Moreover, in a systematic review aimed at determining the clinical readiness of diagnostic, prescriptive and prognostic CPRs involving the physiotherapy management of LBP, Haskins et al critically appraised 25 unique CPRs and subsequently concluded, “the available evidence does not support the direct clinical application of any of the identified CPRs for LBP at this time.”
THE 2-ITEM SPINAL MANIPULATION CPR FOR ACUTE LBP
After reducing the original Flynn et al 5-item spinal manipulation CPR to a 2-item spinal manipulation CPR, Fritz et al reported an 83.7% success rate in patients with acute LBP that were positive on both items—i.e. less than 16 days of pain and without symptoms distal to the knee. Nevertheless, although this abbreviated form of the spinal manipulation CPR was found to strongly identify those patients with a good outcome following treatment, no control group was included in the derivation, thus the two variables in the rule “represent prognostic factors that may have no specific relationship with the intervention provided”–i.e. non-specific prognostic factors that have nothing to do with any kind of manual therapy intervention, or any treatment the patient might receive for that matter; that is, the variables are just predictive of a more favorable prognosis irrespective of treatment. Put another way, individuals with LBP for a very short duration (i.e. less than 2 weeks) that don’t have symptoms below the knee are obviously more likely to spontaneously recover (than those with LBP of longer durations and symptom referral into the lower leg or foot) regardless of whether they receive spinal manipulation or not!
Two subsequent studies[30,31] attempted to validate the Fritz et al 2-item spinal manipulation CPR; however, both studies restricted their samples to only patients that were positive on the 2-item rule. Thus, without the inclusion of patients that are also negative on the 2-item spinal manipulation rule, a prescriptive CPR’s performance cannot be rigorously investigated. Therefore, “the body of evidence does not yet enable confidence in the direct clinical application of either the 5-item or 2-item spinal manipulation CPRs in identifying subgroups of patients with differences in responsiveness to this intervention.” Physical therapists must therefore exercise due caution before using either the 5-item or 2-item spinal manipulation CPR in clinical practice, as predictor variables identified through single-arm study designs may reflect chance associations or non-specific prognostic factors rather than relevant treatment-effect modifiers.
CPRs FOR CHRONIC LOW BACK PAIN
In a randomized clinical trial of 181 patients with chronic LBP that compared spinal manipulation with active exercise therapy, Dougherty et al found “no evidence that a modification of the original Flynn et al CPR can be used to discriminate chronic LBP patients that would benefit more from spinal manipulative therapy.”—i.e. the status on the modified 4-item CPR did not moderate the effectiveness of spinal manipulative therapy. However, the most recent attempt to identify variables from the history and physical examination to predict successful outcomes following spinal manipulation comes from Vavrek et al. In this randomized controlled trial, the authors collected data on pain, disability, sociodemographics, general health, psychosocial characteristics, and objective examination findings from 400 patients receiving spinal manipulation. Despite tracking more than 50 “predictor” variables from the history and physical examination, Vavrek et al found “the pretreatment responder model performed no better than chance in identifying participants who became responders” to spinal manipulation. Notably, post-treatment pain alone (i.e. at 6-weeks from the start of intervention) was more predictive of treatment success following spinal manipulation than any of the other pre or post-treatment predictive models, a finding that is consistent with previous investigations.
No CPRs for the use of spinal manipulation (or stabilization exercises) in patients with acute or chronic LBP have successfully been validated or made it through the clinical impact phase.[2,3,8,10,17,32] Several independent randomized controlled trials and 5 systematic reviews all concluded that the direct clinical application of the Flynn 5-item spinal manipulation CPR is not appropriate in either acute or chronic LBP populations.[2,3,8,10,17-19,32]
For patients that do not improve with self care options, the Joint Clinical Practice Guidelines for Low Back Pain by the American College of Physicians and the American Pain Society recommend “clinicians should consider the addition of nonpharmacologic therapy with proven benefits—for acute low back pain, spinal manipulation; for chronic or subacute low back pain—intensive interdisciplinary rehabilitation, exercise therapy, acupuncture, massage therapy, spinal manipulation, yoga, cognitive-behavioral therapy, or progressive relaxation.” Likewise, the European Guidelines for acute, non-specific LBP recommend “considering (referral for) spinal manipulation for patients who are failing to return to normal activities.” Similarly, for the early management of non-specific low back pain, the National Institute for Health and Clinical Excellence recommends clinicians consider “offering one of the following options, taking into account the patient’s preference: an exercise program, a course of manual therapy (including spinal manipulation), or a course of acupuncture.” Therefore, in accordance with these three guidelines,[33,34,35] perhaps more time should instead be allocated to screening patients with LBP for relative and absolute contraindications to spinal manipulation. Moreover, if not contraindicated, the best predictor may simply be the patient’s response to the treatment.[19,20]
Philip Denema, DPT, ATC, Cert. SMT, Cert. DN, Dip. Osteopractic
Fellow-in-Training, AAMT Fellowship in Orthopaedic Manual Physical Therapy
Director of Clinical Education, Moore Physical Therapy & Fitness, Wilton, CT
Raymond Butts, DPT, PhD, MSc (NeuroSci), Cert. SMT, Cert. DN, Dip. Osteopractic
Coordinator, AAMT Fellowship in Orthopaedic Manual Physical Therapy
Senior Instructor, American Academy of Manipulative Therapy
James Dunning, DPT, MSc (Manip Ther), MMACP (UK), FAAOMPT
Director, AAMT Fellowship in Orthopaedic Manual Physical Therapy
Senior Instructor, Spinal Manipulation Institute & Dry Needling Institute
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