Examination of a Clinical Prediction Ruleto Identify Patients With Neck PainLikely to Benefit From Thoracic SpineThrust Manipulation and a GeneralCervical Range of Motion Exercise:Multi-Center Randomized Clinical TrialJoshua A. Cleland, Paul E. Mintken, Kristin Carpenter, Julie M. Fritz, Paul Glynn,Julie Whitman, John D. Childs

Background. A clinical prediction rule (CPR) purported to identify patients withneck pain who are likely to respond to thoracic spine thrust manipulation hasrecently been developed, but has yet to be validated.

Objective. The purpose of this study was to examine the validity of this CPR.

Design. This was a multi-center randomized clinical trial.

Methods. One hundred forty patients with a primary report of neck pain wererandomly assigned to receive either 5 sessions of stretching and strengtheningexercise (exercise-only group) or 2 sessions of thoracic spine manipulation andcervical range of motion exercise followed by 3 sessions of stretching and strength-ening exercise (manipulation � exercise group). Data on disability and pain werecollected at baseline, 1 week, 4 weeks, and 6 months. The primary aim (treatmentgroup � time � status on the prediction rule) was examined using a linear mixedmodel with repeated measures. Time, treatment group, and status on the rule, as wellas all possible 2-way and 3-way interactions, were modeled as fixed effects, withdisability (and pain) as the dependent variable. Effect sizes were calculated for bothpain and disability at each follow-up period.

Results. There was no 3-way interaction for either disability or pain. A 2-way(group � time) interaction existed for both disability and pain. Pair-wise comparisonsof disability demonstrated that significant differences existed at each follow-up periodbetween the manipulation � exercise group and the exercise-only group. The patientswho received manipulation exhibited lower pain scores at the 1-week follow-upperiod. The effect sizes were moderate for disability at each follow-up period andwere moderate for pain at the 1-week follow-up.

Limitations. Different exercise approaches may have resulted in a differentoutcome.

Conclusions. The results of the current study did not support the validity of thepreviously developed CPR. However, the results demonstrated that patients withmechanical neck pain who received thoracic spine manipulation and exercise ex-hibited significantly greater improvements in disability at both the short- and long-term follow-up periods and in pain at the 1-week follow-up compared with patientswho received exercise only.

J.A. Cleland, PT, PhD, is Professor,Physical Therapy Department,Franklin Pierce University, 5 ChenellDr, Concord, NH 03301 (USA), andPhysical Therapist, RehabilitationServices, Concord Hospital, Con-cord, New Hampshire. Address allcorrespondence to Dr Cleland at:joshcleland@comcast.net.

P.E. Mintken, PT, DPT, is AssistantProfessor, Department of PhysicalTherapy, School of Medicine, Uni-versity of Colorado, Aurora, Colo-rado, and Lead Clinician, Warden-burg Health Center, Universityof Colorado Boulder, Boulder,Colorado.

K. Carpenter, PT, DPT, is PhysicalTherapist, Waldron’s Peak PhysicalTherapy, Boulder, Colorado.

J.M. Fritz, PT, PhD, ATC, is Associ-ate Professor, Department ofPhysical Therapy, University ofUtah, Salt Lake City, Utah, andClinical Outcomes Research Scien-tist, Intermountain Health Care,Salt Lake City, Utah.

P. Glynn, PT, DPT, OCS,FAAOMPT, is Rehabilitation Man-ager, Newton-Wellesley Hospital,Newton, Massachusetts.

J. Whitman, PT, DSc, is Directorof Evidence In Motion’s Ortho-pedic Manual Physical TherapyProgram, Louisville, Kentucky, andAssistant Professor, School ofPhysical Therapy, Regis University,Denver, Colorado.

J.D. Childs, PT, PhD, MBA, is Asso-ciate Professor and Director of Re-search, US Army-Baylor UniversityDoctoral Program in PhysicalTherapy, San Antonio, Texas.

[Cleland JA, Mintken PE, Carpen-ter K, et al. Examination of a clin-ical prediction rule to identify pa-tients with neck pain likely tobenefit from thoracic spine thrustmanipulation and a general cervi-cal range of motion exercise:multi-center randomized clinicaltrial. Phys Ther. 2010;90:1239–1250.]

© 2010 American Physical TherapyAssociation

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September 2010 Volume 90 Number 9 Physical Therapy f 1239

More than 50% of individualstypically will experienceneck pain1 at some point in

their life, and the incidence of neckpain appears to be increasing.2 Theeconomic burden associated withthe treatment of patients with neckpain is high, second only to low backpain (LBP) in annual workers’ com-pensation costs in the United States.3

Patients with neck pain frequentlyare encountered in outpatient phys-ical therapist practice.4 Recent evi-dence has begun to support the ef-fectiveness of many interventionsused by physical therapists for themanagement of neck pain.5–11

One intervention often used by phys-ical therapists in the management ofneck pain is thoracic spine manipu-lation. Based on low-quality evi-dence, a recent Cochrane reviewsuggested that thoracic spine manip-ulation may be beneficial for reduc-ing pain and improving function inpatients with neck pain.12 A recentlypublished guideline for the manage-ment of patients with neck pain hasrecommended the use of thoracicspine thrust manipulation in themanagement of this population.13 Fi-nally, a recent meta-analysis reportedthat thoracic spine manipulation hasbeen shown to be effective in reduc-ing pain and improving function insubgroups of patients, but the in-cluded studies examined only short-term outcomes.14

Recently, a derivation study was con-ducted with a primary goal of devel-

oping a clinical prediction rule(CPR)15 to identify the subgroup ofpatients with neck pain likely to ben-efit from thoracic spine thrust ma-nipulation. In this derivation study,the researchers treated all patientswith thoracic manipulation and ageneral range of motion (ROM) ex-ercise and identified characteristicsof patients who improved mostwhile receiving treatment. Thesecharacteristics were used to define apreliminary prediction rule for iden-tifying patients with neck pain mostlikely to benefit from thoracic spinethrust manipulation. A shortcomingof a derivation study with a singletreatment arm is the inability to de-termine whether the subgroup iden-tified in the study includes patientswho will preferentially benefit fromthe treatment provided or patientswho have a favorable prognosis re-gardless of treatment.16 A controlledtrial, therefore, is required to evalu-ate whether the subgroup identifiedby the CPR derived in the previoussingle-arm study included patientswho preferentially benefited fromthoracic manipulation or simplythose with a favorable prognosis re-gardless of treatment.17,18 The pur-pose of this randomized clinical trialwas to examine the validity of thepreviously derived CPR.

MethodPatients with a primary report ofneck pain seen in 1 of 5 physicaltherapy clinics across the UnitedStates (Concord Hospital, Concord,New Hampshire; Bellin Health, GreenBay, Wisconsin; University of Colo-rado, Aurora, Colorado; WardenburgHealth Center at the University of Col-orado at Boulder, Boulder, Colorado;and Newton-Wellesley Hospital, New-ton, Massachusetts) between July2007 and December 2008 werescreened for eligibility. The exact in-clusion and exclusion criteria from thederivation study15 were used to deter-mine participant eligibility for thistrial. For patients to be eligible to par-

ticipate, they had to have a primaryreport of neck pain with or withoutunilateral upper-extremity symptoms,be between 18 and 60 years of age,and have a Neck Disability Index(NDI) score of at least 20%. Exclusioncriteria included serious pathologies,diagnosis of cervical spinal stenosis (asidentified in the patients’ medical in-take form) or bilateral upper-extremitysymptoms, evidence of central ner-vous system involvement, 2 or morepositive neurologic signs consistentwith nerve root compression, pendinglegal action regarding their neck pain,or inability to adhere to the treatmentand follow-up schedule. All patientsprovided informed consent prior totheir enrollment in the study.

Examination ProceduresPrior to randomization, patients un-derwent a standardized history andphysical examination that were iden-tical to those of the derivationstudy.15 Demographic informationcollected included age, sex, mecha-nism of injury, location and nature ofthe patient’s symptoms, and thenumber of days since onset of symp-toms. Specific details regarding thephysical examination are publishedelsewhere15 and included measuresof muscle length and strength (force-generating capacity), ROM, and ver-tebral mobility and a thoroughscreening examination designed toidentify any contraindications to tho-racic spine manipulation (hyperre-flexia, unsteadiness during walking,nystagmus, loss of visual acuity, im-paired sensation of the face, alteredtaste, the presence of pathologicalreflexes).15 Additionally, any seriouspathologies or conditions (tumor,fracture, metabolic diseases, rheuma-toid arthritis, osteoporosis, history ofprolonged steroid use) identified onthe patient’s medical screening ques-tionnaire were considered contrain-dications to treatment.

All patients completed several com-monly used instruments to assess

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1240 f Physical Therapy Volume 90 Number 9 September 2010

pain and function. The NDI is themost widely used condition-specificdisability scale for patients with neckpain and consists of 10 items ad-dressing different aspects of func-tion, each scored from 0 to 5, with amaximum score of 50 points.19,20

The score then is doubled and inter-preted as a percentage of the patient-perceived disability. Higher scoresrepresent increased levels of disabil-ity. The NDI has been reported to bea reliable and valid outcome measurefor patients with neck pain.19,21–23

An 11-point numeric pain ratingscale (NPRS) was used to measurepain intensity. The scale is anchoredon the left (score of 0) with thephrase “no pain” and on the right(score of 10) with the phrase “worstimaginable pain.” Numeric pain rat-ing scales have been shown to yieldreliable and valid data.24–29 Patientsrated their current level of pain, aswell as their worst and least amountof pain in the previous 24 hours. Theaverage of the 3 ratings was used torepresent the patient’s level of pain.

The Fear-Avoidance Beliefs Ques-tionnaire (FABQ) is a 16-item ques-tionnaire designed to quantify fearand avoidance beliefs in patients withLBP.30 The FABQ has 2 subscales: a7-item scale to measure fear-avoidance beliefs about work(FABQW) and a 4-item scale to mea-sure fear-avoidance beliefs aboutphysical activity (FABQPA). Eachitem is scored from 0 to 6, with pos-sible scores ranging from 0 to 24 forthe FABQPA and from 0 to 42 for theFABQW and with higher scores rep-resenting increased fear-avoidancebeliefs. For this study, the FABQ wasmodified by replacing the word“back” with the word “neck.” Boththe FABQPA and FABQW, also mod-ified in this way, were originallyidentified in the derivation study aspotential predictors associated witha positive response to thoracic spine

thrust manipulation in a patient pop-ulation with neck pain.15

Additionally, at each follow-up pe-riod, patients completed the 15-pointGlobal Rating of Change (GROC) de-scribed by Jaeschke et al.31 The scaleranges from �7 (“a very great dealworse”) to 0 (“about the same”) to �7(“a very great deal better”). It has beenreported that scores of �4 and �5 areindicative of moderate changes inpatient-perceived status and thatscores of �6 and �7 indicate largechanges in patient status.31 Similar tothe study that originally derived theCPR,15 patients who rated their per-ceived recovery on the GROC as “avery great deal better,” “a great dealbetter,” or “quite a bit better” (ie, ascore of �5 or greater) at any of thefollow-up periods were categorizedas a success.

RandomizationOnce the examination was com-plete, patients were randomly as-signed to 1 of 2 groups: (1) patientswho received thoracic spine manip-ulation and an exercise program (ma-

nipulation � exercise group) or (2)patients who received a stretchingand strengthening exercise program(exercise-only group). Concealed al-location was performed by an indi-vidual not involved in data collectionusing a computer-generated random-ized table of numbers created foreach participating site prior to thebeginning of the study. Individual,sequentially numbered index cardswith the random assignment wereprepared. The index cards werefolded and placed in sealed, opaqueenvelopes.

Treating TherapistsTen physical therapists with a meanof 8.7 years (SD�6.9, range�1–21)of clinical experience participated inthe recruitment, examination, andtreatment of all patients in this study.All therapists underwent a standard-ized training regimen, which in-cluded studying a manual of standardprocedures with the operational def-initions of each examination andtreatment procedure. Participatingtherapists underwent a 3-hour train-ing session provided by one of the

The Bottom Line

What do we already know about this topic?

Thoracic spine manipulation appears to be beneficial in the short term forreducing pain and improving function in patients with mechanical neckpain. The authors have attempted to identify a subgroup of patients withneck pain most likely to benefit from thoracic spine manipulation.

What new information does this study offer?

The results suggest that, regardless of the patient’s clinical presentation,those who received thoracic spine manipulation in addition to exercisehad superior outcomes to those who received exercise only. This suggeststhat patients with mechanical neck pain and no contraindications tomanual therapy may benefit from thoracic spine manipulation.

If you’re a patient, what might these findings meanfor you?

If you are experiencing neck pain, thoracic spine manipulation providedby a physical therapist may help in decreasing your level of disability.

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September 2010 Volume 90 Number 9 Physical Therapy f 1241

investigators. Due to the nature ofthe interventions used in this study,therapists could not be blinded.However, individuals who collectedall outcome measures were blindedto group assignment. Both treatingclinicians and outcome assessorswere unaware of patients’ status onthe CPR.

Treatment ProceduresPatients in both groups attended phys-ical therapy sessions twice weekly dur-ing the first week and then onceweekly for the next 3 weeks, for a totalof 5 sessions over a 4-week period.

Exercise-only group. This groupwas treated with a stretching andstrengthening program. Recent guide-lines and reviews have supported theuse of exercise to decrease pain, im-prove function, and reduce disabilityin a patient population with neckpain.32,33 At each session, the physicaltherapist manually stretched the pa-tient’s upper trapezius, scalene, ster-nocleidomastoid, levator scapulae,and pectoralis major and minor mus-cles. Each stretch was held for 30 sec-onds and repeated twice.

Strengthening exercises includeddeep neck flexor training, cervicalisometrics, and middle and lower tra-pezius and serratus anterior muscleexercises. Each exercise was per-formed for 10 repetitions, with agoal of a 10-second hold. A detaileddescription of the strengthening andflexibility program used in this studyis available elsewhere.34 Patients inthe exercise group were instructedto perform the strengthening andflexibility exercises as a home pro-gram once daily. Patients also wereadvised to maintain their usual activ-ity level within the limits of pain.Advice to maintain usual activity hasbeen found to assist in the recoveryfrom neck pain.32,33 Patients wereinstructed to perform all activitiesthat did not increase symptoms and

to avoid activities that aggravatedsymptoms.

Manipulation � exercise group.The treatment received by the ma-nipulation � exercise group differedfrom that of the exercise-only groupfor the first week only (2 treatmentsessions). Beginning in the third ses-sion, these patients received the sametreatment program outlined above forthe exercise group (visits 3–5).

During the first 2 sessions, patientsin the manipulation � exercisegroup received thoracic spine thrustmanipulations and a ROM exerciseonly. All patients received 3 differentthoracic spine thrust manipulationsthat were identical to those used inthe derivation study.15 We will usethe model for describing thrust ma-nipulations as recently proposed byMintken et al35:

1. A high-velocity, midrange, distrac-tion force to the midthoracicspine on the lower thoracic spinein a sitting position. The therapistplaced his or her upper chest atthe level of the patient’s middlethoracic spine and grasped thepatient’s elbows. A high-velocitydistraction thrust was performedin an upward direction.

2. A high-velocity, end-range,anterior-posterior force appliedthrough the elbows to the upperthoracic spine on the midthoracicspine in cervicothoracic flexion.This technique was performedwith the patient positioned su-pine. The therapist used his orher manipulative hand to stabilizethe inferior vertebra of the mo-tion segment targeted and usedhis or her body to push downthrough the patient’s arms toperform a high-velocity, low-amplitude thrust.

3. A high-velocity, end-range,anterior-posterior force appliedthrough the elbows to the middlethoracic spine on the lower tho-racic spine in cervicothoracicflexion. This technique was per-formed with the patient posi-tioned supine. The therapist usedhis or her manipulative hand tostabilize the inferior vertebra ofthe motion segment targeted andused his or her body to pushdown through the patient’s armsto perform a high-velocity, low-amplitude thrust.

Following the manipulations, pa-tients were given the same generalcervical mobility exercise as in thederivation study. The following exer-cise was originally described by Er-hard36 as a general mobility exercisefor patients with neck pain. To per-form this exercise, each patient wasinstructed to place the fingers overthe manubrium. The patient startedwith the chin on the fingers, thenrotated to one side as far as possibleand returned to neutral. This exer-cise was performed alternately toboth sides within pain tolerance.The patient started using 5 fingers,then progressed to 4, 3, 2, and finally1 finger as mobility improved. Thepatient was asked to perform thisexercise for 10 repetitions to eachside, 3 to 4 times per day, withinpain tolerance, each day during par-ticipation in the study. Patients inthis group also were advised to main-tain usual activities that did not in-crease symptoms and to avoid all ac-tivities that exacerbated theirsymptoms.

At the third treatment session, pa-tients in the manipulation � exercisegroup began the exercise programlisted above for the exercise-onlygroup. Patients were treated twice aweek for the first week and thenonce a week for the next 3 weeks,for a total of 5 therapy sessions.

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1242 f Physical Therapy Volume 90 Number 9 September 2010

Identification of the Status onthe RuleAfter the patients completed thestudy, the principal investigator de-termined each patient’s status on therule using data collected at the initialevaluation. Using the same criteriaidentified in the initial study,15 pa-tients who met at least 3 of the fol-lowing criteria were classified aslikely responders (ie, positive on therule). Patients who met 2 or fewer

criteria were classified as likely non-responders (ie,, negative on therule):

1. FABQPA score �12 points

2. Duration of current episode �30days (judged from the patient’sself-report)

3. No symptoms extending distal tothe shoulder (judged from thepain diagram)

4. Decreased cervical extension�30 degrees (measured with abubble inclinometer)

5. Decreased T3–T5 kyphosis (iden-tified during the posturalexamination)

▼▼▼▼

▼

▼ ▼

▼

▼▼

▼

▼▼

▼

PatientsScreened for Eligibility

(N=278)

Randomized (n=140)

Manipulation + Exercise(n=70)

1-Week Follow-up(n=70)

4-Week Follow-up (n=69)Moved (n=1)

6-Month Follow-up (n=60)Did not return

questionnaires (n=10)

6-Month Follow-up (n=54)Did not return

questionnaires (n=16)

4-Week Follow-up (n=68)Lost job (n=1)

Bike accident (n=1)

+CPR(n=33)

–CPR(n=27)

+CPR(n=29)

–CPR(n=25)

1-Week Follow-up (n=70)

Exercise Only (n=70)

• Refused to participate (n=27)• “Red flags” (n=9)• Whiplash (n=29)• Cervical stenosis (n=6)• Central nervous system involvement (n=7)• 2 or more neurological findings (n=35)• Prior surgery (n=3)• Pending legal action (n=7)• Insufficient English skills (n=3)• Unable to adhere to treatment schedule (n=12)

Not Eligible (n=138)

Figure 1.Flow diagram of participant recruitment and retention. �CPR�positive on the clinical prediction rule, –CPR�negative on the clinicalprediction rule.

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September 2010 Volume 90 Number 9 Physical Therapy f 1243

6. Patient reports that looking updoes not aggravate his or hersymptoms (identified during thehistorical examination)

Follow-upFollow-up assessments were per-formed after 1 week (prior to treat-ment on the third visit), at 4 weeks(prior to treatment on the fifth visit),and at 6 months. At each follow-upassessment, patients completed theNDI, NPRS, and GROC. All patientsattended the third visit, allowing fordata collection. If patients did notattend the fifth visit, data were notcollected for that follow-up period.

Sample Size and PowerWe based sample size calculation ondetecting a clinically important dif-ference in NDI score between any ofthe 4 cells of the study based on thepatients’ status on the rule (positiveor negative) and treatment group(manipulation � exercise or exer-cise only) at an alpha level of .05.Based on our previous research,15

we expected a standard deviation ofchange scores on the NDI of 12points. To detect a 10-point changein NDI at the 1-week follow-up with85% power using a 2-tailed hypothe-sis and assuming a 50% distribution

of patients37 who do and do notmeet the rule, 30 patients per cellwere required. We recruited 140 pa-tients to permit approximately a 15%dropout rate or the possibility of un-equal distribution of groups.

Data AnalysisWe examined the primary aim usinga linear mixed model with repeatedmeasures to account for the correla-tion among repeated observationsfrom the same patient. Time, treat-ment group, and status on the rule,as well as all possible 2-way and3-way interactions, were modeled asfixed effects, with the NDI score asthe dependent variable. A first-orderauto-regressive covariance structurewas used for the repeated measures.The primary aim focused on evalua-tion of the 3-way interaction amongtime, treatment group, and status onthe rule. A separate model was con-structed in a similar fashion withpain (NPRS) as the dependent vari-able. Similarly, to investigate the sec-ondary aim of the study, we exam-ined the 2-way (time � group)interaction to determine whether pa-tients who received thoracic manip-ulation achieved superior outcomesregardless of status on the rule. Wealso examined the 2-way interaction

between status on the rule and timeto determine whether rule statuswas an important prognostic factorregardless of treatment received.Treatment effects were calculatedfrom the between-group differencesin change score from baseline tothe 1-week, 4-week, and 6-monthfollow-up periods. As a secondaryanalysis, we examined the effects oftreatment, rule status, and the inter-action between treatment and rulestatus at each follow-up point usingseparate mixed model analyses, withthe NDI score at each follow-uppoint as the dependent variable.Treatment group, rule status, and theinteraction between treatment andrule status were included as fixedeffects, and the baseline NDI scorewas included as a fixed effect covari-ate. Similar analyses were performedto examine NPRS scores at eachfollow-up point. No patients wereremoved from the analysis for lack ofadherence to treatment procedures.Missing data points were estimatedin the mixed model analyses usingrestricted maximum likelihood ratioestimation with 100 iterations.

We calculated the effect size usingthe Cohen d coefficient betweenthe manipulation � exercise and

Table 1.Baseline Demographic and Self-Report Variables for all Treatment Groupsa

Variable

AllPatients(N�140)

Manipulation� Exercise

Group(n�70)

Manipulationand �CPR

(n�37)

Manipulationand �CPR

(n�33)

Exercise-Only Group

(n�70)

Exerciseand �CPR

(n�38)

Exerciseand �CPR

(n�32)

Age (y), mean (SD) 39.9 (11.3) 39.2 (10.5) 37.0 (10.2) 41.6 (10.4) 40.6 (12.0) 41.8 (12.8) 39.2 (11.1)

Sex (female) 97.0 (69%) 46.0 (66%) 27.0 (73%) 19 (57%) 51.0 (72.9%) 27.0 (71.1%) 24.0 (75%)

Days since onset,mean (SD)

63.5 (57.2) 62.5 (53.3) 53.1 (47.0) 73.0 (58.5) 64.4 (61.3) 47.6 (46.5) 84.4 (70.9)

Medication use forneck pain

52.0 (37%) 23.0 (33%) 13.0 (35%) 10.0 (30.3%) 29.0 (41.4%) 15.0 (39.5%) 14.0 (43.8%)

FABQPA, mean(SD)

11.1 (5.6) 11.5 (5.5) 9.4 (4.9) 13.9 (5.2) 10.6 (5.8) 8.8 (5.7) 12.8 (5.0)

FABQW, mean(SD)

10.6 (7.7) 10.97 (7.5) 9.3 (8.1) 12.8 (6.5) 10.2 (7.9) 9.8 (7.9) 10.6 (7.9)

a �CPR�positive on the clinical prediction rule, �CPR�negative on the clinical prediction rule, FABQPA�Fear-Avoidance Beliefs Physical Activity Subscale(range�0–24), FABQW�Fear-Avoidance Beliefs Work Subscale (range�0–42).

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1244 f Physical Therapy Volume 90 Number 9 September 2010

exercise-only groups at eachfollow-up period.38 An effect size of0.2 was considered small, 0.5 mod-erate, and 0.8 large.38 We also com-pared the number of successful out-comes between groups. Patientswho rated their perceived recoveryon the GROC as “a very great dealbetter,” “a great deal better,” or“quite a bit better” (ie, a score of �5or greater) at each follow-up periodwere classified as having a successful

outcome, based on the initialstudy.15 The percentage of patientsexperiencing a successful outcomeat each time period between groupswas examined using a chi-square testof independence. We then calcu-lated the numbers needed to treat(NNT) and 95% confidence intervals(CI) at the 1-week, 4-week, and6-month follow-up periods. We usedan intention-to-treat analysis, withpatients analyzed in the group to

which they were allocated for theGROC analysis. Missing data were re-placed with the mean score of therespective group for each missingGROC value. Data analysis was per-formed using SPSS version 15.*

Role of the Funding SourceFunding was provided by the Foun-dation for Physical Therapy and theOrthopaedic Section of the Ameri-can Physical Therapy Association.The funding agency had no role inthe study design, writing of themanuscript, or the decision to sub-mit the manuscript for publication.

ResultsTwo hundred seventy-eight consec-utive patients with neck pain werescreened for possible eligibility. Onehundred forty patients, mean age39.9 years (SD�11.3) (69% female),satisfied the eligibility criteria andagreed to participate. Seventy pa-tients were randomly assigned to re-ceive manipulation and exercise,and 70 patients were randomly as-

* SPSS Inc, 233 S Wacker Dr, Chicago, IL60606.

Table 2.Disability and Pain Scores for All Groups at Each Follow-up Perioda

Group Baseline (95% CI) 1 Week (95% CI) 4 Weeks (95% CI) 6 Months (95% CI)

Neck Disability Index

Manipulation � exercise 29.5 (27.7, 31.3) 14.8 (13.1, 16.5) 10.1 (8.6, 11.5) 7.1 (5.4, 8.7)

Manipulation and �CPR 28.0 (25.5, 30.5) 12.5 (10.2, 14.9) 8.2 (6.2, 10.2) 6.3 (4.1, 8.5)

Manipulation and �CPR 31.0 (28.4, 33.7) 17.0 (14.5, 19.4) 11.9 (9.8, 14.0) 7.9 (5.4, 10.3)

Exercise only 28.6 (26.7, 30.4) 18.4 (16.7, 20.1) 13.5 (12.0, 15.0) 11.7 (10.0, 13.4)

Exercise and �CPR 27.7 (25.2, 30.1) 18.2 (15.9, 20.5) 13.6 (11.5, 15.7) 11.8 (9.8, 14.1)

Exercise and �CPR 29.4 (26.8, 32.1) 18.6 (16.1, 21.1) 13.4 (11.3, 15.6) 11.6 (9.1, 14.1)

Numeric Pain Rating Scale

Manipulation � exercise 4.4 (4.0, 4.7) 2.3 (2.0, 2.5) 1.7 (1.4, 1.9) 1.4 (1.1, 1.7)

Manipulation and �CPR 4.3 (3.8, 4.8) 1.9 (1.6, 2.3) 1.6 (1.3, 2.0) 1.5 (1.1, 1.8)

Manipulation and �CPR 4.5 (4.0, 5.0) 2.6 (2.2, 3.0) 1.7 (1.4, 2.1) 1.3 (0.9, 1.7)

Exercise only 3.9 (3.6, 4.3) 3.0 (2.7, 3.2) 1.9 (1.6, 2.1) 1.8 (1.5, 2.0)

Exercise and �CPR 4.4 (3.9, 4.8) 3.1 (2.7, 3.4) 2.0 (1.7, 2.3) 1.8 (1.4, 2.2)

Exercise and �CPR 3.5 (3.0, 4.0) 2.9 (2.5, 3.3) 1.7 (1.4, 2.1) 1.7 (1.3, 2.2)

a 95% CI�95% confidence interval, �CPR�positive on the clinical prediction rule, �CPR�negative on the clinical prediction rule.

Figure 2.Mean scores for the Neck Disability Index for each treatment group relative to status onthe clinical prediction rule.

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September 2010 Volume 90 Number 9 Physical Therapy f 1245

signed to receive exercise only. Fig-ure 1 shows a flow diagram of pa-tient recruitment and retention.Baseline variables for all groups areshown in Table 1. Recruitment ofpatients was not equally distributedamong the participating clinics, withrates of 34%, 26%, 19%, 16%, and 5%across sites. The overall long-term re-sponse rate was 81.0%. The dropoutrates were 14% (n�10) for the ma-nipulation � exercise group and

23% (n�16) for the exercise-onlygroup. No reasons were provided forthe long-term follow-up dropouts.No adverse events were reportedfor either group during the trial.Disability and pain scores for eachfollow-up period are shown inTable 2.

Repeated-measures analyses failed toreveal a significant 3-way interactionfor either NDI scores (P�.79) or

NPRS scores (P�.22). This findingindicates that outcomes over timewere not dependent upon the com-bination of a patient’s treatmentgroup and status on the rule (Figs. 2and 3). Mean scores for the NDI andpain for each treatment group rela-tive to status on the rule are reportedin Table 2.

There was a significant 2-way inter-action between group and time forboth the NDI (P�.01) and the NPRS(P�.003). Regardless of their statuson the rule, patients who receivedmanipulation and exercise experi-enced greater improvements in dis-ability and pain across time than pa-tients who received exercise alone.Estimated marginal means for theNDI by group at each time period aregraphed in Figure 4. There were nosignificant 2-way interactions be-tween rule status and time for eitherdisability (P�.71) or pain (P�.26)(Fig. 5).

Results of the secondary analyses ex-amining the effects of treatment, rulestatus, and the interaction betweentreatment and rule status at eachfollow-up period demonstrated thatthe manipulation � exercise groupexperienced significantly lower scoresfor disability at 1 week (P�.003), 4weeks (P�.001), and 6 months(P�.001) and for pain at 1 week(P�.001) than patients who re-ceived exercise alone (Tab. 3). Therewas a significant interaction be-tween status on the rule and treat-ment received for disability at 1week (P�.011) and 4 weeks (P�.05)and the NPRS score after 1 week(P�.014); however, the differenceswere similar when compared withthe manipulation � exercise inter-vention versus the exercise-only in-tervention, a finding that does notsupport the value of the predictionrule (Fig. 3).

Effect sizes for disability at the1-week, 4-week, and 6-month

Figure 3.Mean scores for pain for each treatment group relative to status on the clinical predic-tion rule.

Figure 4.Mean scores for the Neck Disability Index by group at each time period. Asteriskindicates statistically significant difference between groups.

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follow-up periods were 0.51, 0.48,and 0.65, respectively. Effect sizesfor pain were 0.54 for the 1-weekfollow-up, 0.18 for the 4-weekfollow-up, and 0.25 at the 6-monthfollow-up. Using an intention-to-treatanalysis, after 1 week, 18.5% (13/70)of the patients in the manipulation �exercise group achieved success,which was defined as having scoresof �5 or greater on the GROC, com-pared with 11.4% (8/70) of the pa-tients in the exercise-only group.There was no statistically significant

difference between groups (P�.17).After 4 weeks, a significant differ-ence existed between groups, with51.4% (36/70) of the patients in themanipulation � exercise group and31.4% (22/70) of the patients in theexercise-only group achieving suc-cess (P�.01). There also was a sig-nificant difference between groupsat the 6-month follow-up period,with 80% (56/70) of patients in themanipulation � exercise groupachieving success and 35.7% (25/70)of the patients in the exercise-only

group achieving success. Figure 6demonstrates the success ratesacross time for each group. The NNTfor the manipulation � exercisegroup was 15 (95% CI��4.6, 18.9)at the 1-week-follow-up, 6 (95%CI�1.9, 34.8) at the 4-week follow-up, and 4 (95% CI�2.1, 7.5) at the6-month follow-up.

DiscussionIt is essential to validate a CPR priorto incorporating it into widespreadclinical practice.17,18 Therefore, wesought to examine whether a pre-viously derived CPR15 exhibited va-lidity for identifying a subgroup ofpatients with neck pain who re-sponded favorably to thoracic ma-nipulation. The derived CPR wasbased on the identification of clinicalfindings that predicted a good out-come in a cohort of patients withneck pain who received thoracic ma-nipulation. Validation of a previouslyderived CPR needs to be performedusing a study that includes random-ization to different treatments to de-termine whether the clinical findingscan be used to describe a subgroupof patients who preferentially re-spond to thoracic manipulation. The

Table 3.Secondary Analyses Examining the Effects of Treatment, Rule Status, and the Interaction Between Treatment and Rule Status atEach Follow-upa

Group Disability Score (95% CI) P Pain Score (95% CI) P

1 week

Manipulation � exercise vs exercise only �3.6 (�6.0, �1.2) .003 �0.70 (�1.1, �0.32) �.001

�CPR vs �CPR �2.4 (�4.9, 0.17) .07 �0.26 (�0.64, 0.12) .18

Manipulation � status on the rule �4.4 (�7.8, �1.0) .011 �0.68 (�1.2, �0.14) .014

4 weeks

Manipulation � exercise vs exercise only �3.5 (�5.6, �1.3) .001 �0.19 (�0.53, 0.16) .29

�CPR vs �CPR �1.8 (�4.0, 0.30) .05 0.08 (�0.26, 0.43) .63

Manipulation � status on the rule �3.9 (�6.7, �0.85) .012 �0.08 (�0.56, 0.40) .74

6 months

Manipulation � exercise vs exercise only �4.6 (�7.0, �2.2) �.001 �0.35 (�0.75, 0.04) .08

�CPR vs �CPR �0.68 (�3.1, 1.7) .09 0.09 (�0.30, 0.49) .64

Manipulation � status on the rule �1.6 (�4.8, 1.7) .35 0.14 (�0.40, 0.69) .61

a 95% CI�95% confidence interval, �CPR�positive on the clinical prediction rule, �CPR�negative on the clinical prediction rule. For both pain anddisability, negative values represent better outcomes.

Figure 5.Mean scores for pain by group at each time period. Asterisk indicates statisticallysignificant difference between groups.

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September 2010 Volume 90 Number 9 Physical Therapy f 1247

current study sought to broadly val-idate the CPR in a multi-site trial us-ing a sound methodological design.39

The results of this study generallyfailed to validate the CPR. The resultsof our study indicated that regardlessof a patient’s status on the CPR,those who received thoracic spinemanipulation exhibited reductionsin pain at 1 week and improvementsin disability at 1 week, 4 weeks, and6 months that were statistically sig-nificant. The effect sizes for disabilitywere moderate at each follow-up pe-riod and were moderate for pain atthe 1-week follow-up. The benefitsof targeting manipulation to patientswho were positive on the CPR weremarginal and were evident only atthe short-term (1- and 4-week)follow-ups. It does not appear thatclinical decision making based onthe CPR is likely to improve clinicaloutcomes; therefore, the CPR cannotbe advocated for adoption into clin-ical practice. The results of this studysuggest that short- and long-term out-comes would be improved by pro-viding thoracic manipulation regard-less of status on the CPR.

There are several reasons why a CPRthat is derived in one cohort of pa-tients with a single treatment armmay not be validated in a follow-up

clinical trial. First, findings in the der-ivation study may have been due tochance associations or to associa-tions idiosyncratic to the originalsample and, therefore, would not bereplicated in a new sample of pa-tients.16,40 It also is possible that theclinicians in this study did not inter-pret or measure the clinical factorscomprising the CPR in the samemanner as the clinicians in the orig-inal study. This possibility seems un-likely due to the nature of the clinicalfactors in the CPR and their demon-strated interrater reliability.7 Finally,it is possible that a CPR derived froma single treatment arm study may beidentifying factors that generallyidentify patients with a good progno-sis, but not specifically related to re-ceiving the treatment being stud-ied.16 This possibility does notappear to have occurred in this in-stance because the current study didnot identify status on the CPR as re-lated to prognosis. It seems mostlikely that the results of the deriva-tion study were based on eitherchance associations or findingsunique to the sample of patients inthe original study.

The results of this study are in agree-ment with those of studies that ex-amined the impact of thoracic

spine manipulation in patients withacute or subacute mechanical neckpain.5,41,42 The current study alsodemonstrates that patients withneck pain who received thoracicspine manipulation continued toexperience greater improvementsat the long-term follow-up. Theminimal clinically important differ-ence (MCID) for the NDI has beenreported to range from 10% to 19%.We recognize that the differencesbetween groups, although statisti-cally significant, did not surpass theMCID. However, the percentage ofindividuals who experienced a suc-cessful outcome on the GROC wassignificantly greater in the manipu-lation � exercise group comparedwith the exercise-only group at 4weeks and 6 months. Additionally,the NNT at the 4-week and 6-monthfollow-up periods was 6 and 4, re-spectively, providing further evi-dence for the use of thoracic spinemanipulation in addition to exer-cise in this population. This findingsuggests that perhaps individualswith neck pain who do not haveany contraindications to manipula-tion or meet any of the exclusioncriteria should receive thoracicspine thrust manipulation regard-less of additional factors in the clin-ical presentation. It also should berecognized that a statistically signif-icant interaction for pain occurredbetween manipulation and statuson the rule at the 1-week follow-upperiod. Although the treatment ef-fects for reductions in pain forthose who satisfied the rule at 1week were similar to those whencomparing the manipulation � ex-ercise and exercise-only groups,we feel the results of the currentstudy do not warrant utilization ofthe rule. Clinical prediction rulesare valuable only if they improvepatient outcomes.17 The results ofthe current study suggest that usingthe rule does not improve patientcare and that patients with neckpain and no contraindications to

Figure 6.Success rates across time for each group. Success was defined as scoring �5 or greateron the Global Rating of Change scale. Asterisk indicates statistically significant differencebetween groups.

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manipulation should receive tho-racic spine manipulation regardlessof clinical presentation.

A limitation of the current study isthat, although the exercise regimenwas based on current publishedguidelines, no agreement exists as tothe most effective exercises for thetreatment of patients with neck pain.Therefore, it is possible that differentexercise approaches may have re-sulted in a different outcome. Addi-tionally, although the distributionof patients who satisfied the rulewas close to our expected 50% ineach treatment group, future stud-ies should consider using stratifiedrandomization to ensure equaldistribution.

ConclusionThe results of the current study didnot support the validity of the pre-viously developed CPR.15 How-ever, the 2-way interaction be-tween group and time suggests thatpatients with mechanical neck painwho do not exhibit any contraindi-cations to manipulation exhibit sta-tistically significant improvementsin disability in both the short- andlong-term follow-up periods.

Dr Cleland, Dr Mintken, Dr Fritz, Dr Whit-man, and Dr Childs provided concept/idea/research design and writing. Dr Cleland, DrMintken, Dr Carpenter, and Dr Glynn pro-vided data collection and participants. DrCleland and Dr Fritz provided data analysis.Dr Cleland provided project management.Dr Cleland, Dr Whitman, and Dr Childs pro-vided fund procurement. Dr Cleland, DrMintken, and Dr Carpenter provided facili-ties/equipment. Dr Cleland, Dr Mintken, DrCarpenter, Dr Fritz, Dr Whitman, and DrChilds provided consultation (including re-view of manuscript before submission). Theauthors thank all of the clinicians who par-ticipated in data collection and treatment ofthe patients in this clinical trial.

Institutional review board approval wasgranted at each participating site: ConcordHospital, Concord, New Hampshire; BellinHealth, Green Bay, Wisconsin; Universityof Colorado, Aurora, Colorado; Warden-burg Health Center at the University of

Colorado at Boulder, Boulder, Colorado;and Newton-Wellesley Hospital, Newton,Massachusetts.

The results of this study were presented atthe Combined Sections Meeting of theAmerican Physical Therapy Association; Feb-ruary 17–20, 2010; San Diego, California.

Funding was provided by the Foundationfor Physical Therapy and the OrthopaedicSection of the American Physical TherapyAssociation.

Trial registration: ClinicalTrials.gov. NCT00504686.

This article was submitted April 6, 2010, andwas accepted June 6, 2010.

DOI: 10.2522/ptj.20100123

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management of chronic neck pain in gen-eral practice: a retrospective study. ScandJ Prim Health Care. 1999;17:215–220.

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3 Wright A, Mayer T, Gatchel R. Outcomesof disabling cervical spine disorders incompensation injuries: a prospective com-parison to tertiary rehabilitation responsefor chronic lumbar disorders. Spine. 1999;24:178–183.

4 Jette AM, Smith K, Haley SM, et al. Physicaltherapy episodes of care for patients withlow back pain. Phys Ther. 1994;74:101–110.

5 Cleland JA, Childs JD, McRae M, et al.Immediate effects of thoracic manipula-tion in patients with neck pain: a ran-domized clinical trial. Man Ther. 2005;10:127–135.

6 Cleland JA, Whitman JM, Fritz JM, et al.Manual physical therapy, cervical traction,and strengthening exercises in patientswith cervical radiculopathy: a case series.J Orthop Sports Phys Ther. 2005;35:802–811.

7 Hoving JL, Koes BW, de Vet HC, et al. Man-ual therapy, physical therapy, or contin-ued care by a general practitioner for pa-tients with neck pain: a randomized,controlled trial. Ann Intern Med. 2002;136:713–722.

8 Waldrop MA. Diagnosis and treatment ofcervical radiculopathy using a clinical pre-diction rule and a multimodal interventionapproach: a case series. J Orthop SportsPhys Ther. 2006;36:152–159.

9 McKinney LA. Early mobilisation and out-come in acute sprains of the neck. BMJ.1989;299:1006–1008.

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11 Ylinen J, Takala EP, Nykanen M, et al. Ac-tive neck muscle training in the treatmentof chronic neck pain in women: a random-ized controlled trial. JAMA. 2003;289:2509–2516.

12 Gross A, Miller J, D’Sylva J, et al. Mani-pulation or mobilisation for neck pain.Cochrane Database Syst Rev. 2010;1:CD004249.

13 Childs JD, Cleland JA, Elliott JM et al. Neckpain: clinical practice guidelines linked tothe International Classification of Func-tioning, Disability and Health from theOrthopedic Section of the American Phys-ical Therapy Association. J Orthop SportsPhys Ther. 2008;38:A1–A34.

14 Walser RF, Meserve BB, Boucher TR. Theeffectiveness of thoracic spine manipula-tion for the management of musculoskel-etal conditions: a systematic review andmeta-analysis of randomized clinical trials.J Man Manip Ther. 2009;17:237–246.

15 Cleland JA, Childs JD, Fritz JM, et al. De-velopment of a clinical prediction rule forguiding treatment of a subgroup of pa-tients with neck pain: use of thoracicspine manipulation, exercise, and patienteducation. Phys Ther. 2007;87:9–23.

16 Hancock M, Herbert RD, Maher CG. Aguide to interpretation of studies investi-gating subgroups of responders to physi-cal therapy interventions. Phys Ther.2009;89:698–704.

17 McGinn T, Guyatt G, Wyer P, et al. Users’guides to the medical literature, XXII: howto use articles about clinical decision rules.JAMA. 2000;284:79–84.

18 Sackett DL, Haynes RB, Guyatt GH, et al.Clinical Epidemiology: A Basic Sciencefor Clinical Medicine. Boston, MA: Little,Brown & Co Inc; 1991.

19 Vernon H, Mior S. The Neck Disability In-dex: a study of reliability and validity. JManipulative Physiol Ther. 1991;14:409–415.

20 Stratford P, Binkley J, Riddle D, et al. Sen-sitivity to change of the Roland-MorrisBack Pain Questionnaire: part 1. PhysTher. 1998;78:1186–1196.

21 Hains F, Waalen J, Mior S. Psychometricproperties of the Neck Disability Index. JManipulative Physiol Ther. 1989;21:75–80.

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27 Jensen MP, Turner JA, Romano JM. What isthe maximum number of levels needed inpain intensity measurement? Pain. 1994;58:387–392.

28 Price D, Bush F, Long S, et al. A compari-son of pain measurement characteristicsof mechanical visual analog and simple nu-merical rating scales. Pain. 1994;56:217–226.

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34 Carpenter KJ, Mintken P, Cleland JA. Eval-uation of outcomes in patients with neckpain treated with thoracic spine manipu-lation and exercise: a case series. NewZealand Journal of Physiotherapy. 2009;37:71–80.

35 Mintken PE, DeRosa C, Little T, et al.AAOMPT clinical guidelines: a model forstandardizing manipulation terminology inphysical therapy practice. J Orthop SportsPhys Ther. 2008;38:A1–A6.

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Invited Commentary Mark J. Hancock

The study published by Cleland et al1

in this issue of PTJ is an importantaddition to the physical therapy lit-erature. I believe the value of thearticle extends well beyond the pri-mary findings of the study. The studyis one of very few high-quality stud-ies investigating subgroups of pa-tients who respond to specific phys-ical therapy interventions. The studyprovides a model for future researchin the area and some importantwarnings when interpreting otherlower-quality evidence.

Physical therapists have a wide rangeof treatment options for treating pa-tients with musculoskeletal disor-ders, including neck pain. Identify-ing subgroups of patients who bestrespond to specific interventions hasbeen suggested as a research priori-ty2 and has the potential to improvepatient outcomes. Some subgroupsare defined by a single feature suchas patient’s sex. However, in otherconditions, clinicians and research-ers argue that knowledge of a com-

bination of findings is required toidentify an important subgroup. Aclinical prediction rule (CPR) is atool that enables a combination ofpatient characteristics to be consid-ered simultaneously to help in iden-tifying a subgroup.3 There has beendebate in the physical therapy liter-ature about appropriate study de-signs to develop and validate CPRsthat identify subgroups of respond-ers to specific interventions.4–6

There is general agreement, how-ever, that a randomized controlledtrial (RCT) is required before a CPRcan confidently be considered topredict response to a specific inter-vention. Unfortunately, to date veryfew CPRs that aim to identify re-sponders to treatment have beentested in RCTs.4

The trial by Cleland et al is a high-quality study with the primary aim ofinvestigating whether the subgroupof patients with neck pain who meeta CPR respond better to thoracicspine thrust manipulation than pa-

tients who do not meet the CPR. TheCPR was developed in a previoussingle-arm trial,7 so it was unclearwhether the CPR identified responseto thrust manipulation or simply fa-vorable prognosis.6 Cleland et alfound that the CPR did not identifypatients who respond best to tho-racic spine thrust manipulation. Al-though this finding is disappointing,it is still important, as it demon-strates that subgroups identified insingle-arm trials must be tested inRCTs before being considered sub-groups who respond to a specificintervention. I would go a step fur-ther and say the RCT is the first truetest of the subgroup (based on aCPR) as a predictor of response to anintervention and as such should notbe called a validation study. I notethat the current article does not in-clude validation in the title, which Ithink is important. The literature onCPR development refers to a studyfollowing the derivation of a CPR asa validation study.3 However, the as-sumption is that both studies used an

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