Research Report

Preliminary Examination of a
Proposed Treatment-Based
Classification System for Patients
Receiving Physical Therapy

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Interventions for Neck Pain
Julie M Fritz, Gerard P Brennan
JM Fritz, PT, PhD, ATC, is Associate
Professor, Division of Physical
Background and Purpose Therapy, University of Utah, and
Neck pain frequently is managed by physical therapists. The development of classi- Clinical Outcomes Research Scien-
fication methods for matching interventions to subgroups of patients may improve tist, Intermountain Health Care,
clinical outcomes. The purpose of this study was to describe a proposed classification 520 Wakara Way, Salt Lake City,
UT 84108 (USA). Address all
system for patients with neck pain by examining data for consecutive patients correspondence to Dr Fritz at:
receiving physical therapy interventions. julie.fritz@hsc.utah.edu.

GP Brennan, PT, PhD, is Director

Subjects and Methods for Clinical Quality and Outcomes,
Standardized methods for collecting baseline and intervention data were used for all Rehabilitation Agency, Intermoun-
patients receiving physical therapy interventions for neck pain over 1 year. Outcome tain Health Care.
variables were the Neck Disability Index (NDI), numeric pain rating, and number of [Fritz JM, Brennan GP. Prelimi-
visits. Treatment was provided at the discretion of the physical therapist. After the nary examination of a proposed
completion of treatment, each patient was classified by use of baseline variables. The treatment-based classification sys-
interventions received by the patient were categorized as being matched or not matched tem for patients receiving physical
therapy interventions for neck
to the classification. Outcomes for patients who received matched interventions were pain. Phys Ther. 2007;87:513–524.]
compared with those for patients who received nonmatched interventions. The inter-
rater reliability of the classification algorithm was examined with a subset of 50 patients. © 2007 American Physical Therapy
Association

Results
A total of 274 patients were included in this study (74% women; age
[X⫾SD]⫽44.4⫾16.0 years). The most common classification was centralization
(34.7%); next were exercise and conditioning (32.8%) and mobility (17.5%). The
interrater reliability for classification decisions was high (kappa⫽.95, 95% confidence
interval [CI]⫽0.87–1.0). A total of 113 patients (41.2%) received interventions
matched to the classification. Receiving matched interventions was associated with
greater improvements in the NDI (mean difference⫽5.6 points, 95% CI⫽2.6 – 8.6)
and in pain ratings (mean difference⫽0.74 point, 95% CI⫽0.21–1.3) than receiving
nonmatched interventions.

Discussion and Conclusion

The development of classification methods for patients with neck pain may improve
the outcomes of physical therapy intervention. This study was done to examine a
previously proposed classification system for patients receiving physical therapy
interventions for neck pain. Receiving interventions matched to the classification
system was associated with better outcomes than receiving nonmatched interven-
tions. Although the design of this study prohibited drawing conclusions about the
effectiveness of the system, the results suggest that further research on the system Post a Rapid Response or
may be warranted. find The Bottom Line:
www.ptjournal.org

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Treatment-Based Classification System for Patients With Neck Pain

N
eck pain is a common condi- but little work on validation has been ting this subgroup recommends mo-
tion, with an annual incidence performed. We recently proposed a bilization,37 neck active range-of-
estimated at about 15%.1 Pa- treatment-based classification ap- motion (ROM) exercises, and
tients with neck pain frequently are proach that seeks to use information avoidance of immobilization (eg, cer-
treated without surgery by primary from the history and physical exam- vical collar).38,39 Finally, the head-
care and physical therapy provid- ination to place patients into 1 of 5 ache classification includes patients
ers.2– 4 Within physical therapy, separate subgroups that provide a di- with a chief complaint of headache
there appears to be a great deal of rection for the initial physical ther- presumed to originate from struc-
variation in choices of interven- apy treatment approach.22 tures in the cervical spine.40 The ev-
tions,5 indicating a degree of uncer- idence for physical therapy interven-
tainty about optimal strategies for The classification strategy was devel- tions for patients with cervicogenic

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these patients.6 Increased variability oped on the basis of evidence when headaches supports strengthening of
in treatments has been suggested to possible, supplemented with expert the deep neck flexor and upper-
adversely affect the quality of care7; opinion and common practice when quarter muscles along with mobiliza-
this effect may partly explain why necessary.22 The rationale for the tion or manipulation of the cervical
research on physical therapy out- mobility classification is based on ev- spine.41
comes has revealed smaller effect idence generally supporting the use
sizes for patients with neck pain than of manual therapy (either manipula- Classification systems are designed
for patients with other musculo- tion or mobilization) for patients with to direct treatment and improve out-
skeletal conditions.3 neck pain, particularly when these in- comes. Proposed systems should be
terventions are combined with exer- examined to determine whether
The literature on the nonsurgical cise.25 Further evidence from random- treatment decision making that
treatment of patients with low back ized trials suggests that manipulation matches the recommendation of a
pain suggests that suboptimal clini- or mobilization may be more effective system results in better outcomes.
cal outcomes and practice variability for younger patients with more acute Little work has been done to exam-
may be related to the inability to symptoms and without signs of nerve ine proposed classification systems
identify a pathoanatomical cause for root compression.26 –29 for patients with neck pain. We
the majority of patients, creating un- sought to begin the process of exam-
certainty among practitioners oper- The rationale for the centralization ining the proposed system by pro-
ating within the traditional medical classification is based on research spectively collecting standardized in-
model.8 –10 It appears that the precise demonstrating the prognostic signif- formation from the examination,
pathological etiology underlying icance of the centralization phenom- interventions, and clinical outcomes
many cases of neck pain may be sim- enon.30 For patients with distal of patients receiving physical ther-
ilarly elusive.11–14 Recognition of the symptoms and signs of nerve root apy interventions for neck pain. We
inadequacy of the medical model for compression, the promotion of cen- purposefully did not attempt to stan-
the condition of low back pain has tralization of symptoms is recom- dardize the treatment decision mak-
led to the development of alternative mended as a treatment goal, and ing of the therapists. The purposes
methods for classifying patients into interventions such as retraction ex- of this study were to examine the
subgroups based on clinical charac- ercises and traction often are used.31 proposed treatment-based classifica-
teristics to assist in treatment deci- The rationale for the exercise and tion system by describing the preva-
sion making.15–17 There is evidence conditioning classification is based lence of the subgroups in a sample of
that these efforts can improve clini- on evidence of the effectiveness of patients receiving physical therapy
cal outcomes for patients receiving exercise—in particular, strengthen- interventions for neck pain and to
physical therapy interventions.18 –21 ing exercises for the deep neck compare the other characteristics of
flexor, cervical spine, and upper- patients placed in these subgroups.
The development of classification quarter muscles—for patients who We also sought to examine the
methods based on clinical character- have chronic neck pain but who do interrater reliabilities of the classifi-
istics for the purpose of specifically not have signs of nerve root com- cation algorithm and the treatment-
directing nonsurgical treatment pression.32–36 The pain control clas- matching criteria and to compare the
choices has not advanced for the sification encompasses patients with clinical outcomes of care when treat-
condition of neck pain as it has for acute, traumatic onset of neck pain ment decision making matched the
low back pain. Several authors have with a whiplash mechanism and system with the outcomes of care
proposed strategies for the classifica- with very high levels of pain and when decision making was not
tion of patients with neck pain,22–24 disability. Evidence for patients fit- matched to the system.

514 f Physical Therapy Volume 87 Number 5 May 2007

 Treatment-Based Classification System for Patients With Neck Pain

Method Table 1.
Procedures Variables Standardized for Collection at the Baseline Examination for All Patients
Data for this study were collected Variables Measurement Method
from 4 outpatient physical therapy
Duration of symptoms (d) Patient self-report
clinics of Intermountain Health Care,
a private, nonprofit health care sys- Mode of onset of symptoms (gradual, sudden, Patient self-report
tem. In each participating clinic, traumatic, other)
clinical outcomes are routinely Symptom location (neck, head, scapula, shoulder, arm, Patient self-report
tracked for all patients receiving hand) and most bothersome symptom location
physical therapy interventions. Each Aggravating or relieving factors Patient self-report
new patient is entered into an elec-

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Prior history of neck pain (yes or no) and frequency of Patient self-report
tronic database, and at each physical prior episodes
therapy session, a condition-specific Disability attributable to neck pain Neck Disability Index43
disability outcome score and a nu-
Pain intensity 11-point numeric pain rating42
meric pain rating (from 0 to 10)42 are
collected and entered into the data- Signs of nerve root compression (diminished strength, Neurological examination
base. For patients with neck pain, reflex, sensation)
the Neck Disability Index (NDI)43 is Cervical extension, flexion, side bending, and rotation Inclinometer measurement
the condition-specific disability mea- (active range of motion)
sure used at each session. The NDI Effect of cervical active range of motion on symptoms Patient self-report during range-
comprises 10 items related to neck (increased pain, decreased pain, centralization, of-motion assessment24
pain and the patient’s tolerance for peripheralization)
daily activities, each scored from 0 to
5; the scores are summed and ex-
pressed as a percentage. The NDI is
the most commonly used region-
Table 2.
specific scale for patients with neck
Matched Treatment Components for Each Classification Category
pain44 and has been demonstrated to
be a reliable and valid outcome mea- Classification Criterion Proposed Matched Treatment
sure for patients with neck pain.45– 48 Components
Mobility The listed interventions Cervical or thoracic mobilization or
This study was a prospective longi- must both be manipulation
tudinal project involving the collec- received within the Strengthening exercises for the deep
first 3 sessions. neck flexor muscles
tion of standardized data from the
examination, interventions, and out- Centralization Either of the listed Mechanical or manual cervical traction
interventions must (at least 50% of the sessions)
comes of patients receiving physical
be received. Cervical retraction exercises (at least
therapy interventions for neck pain. 50% of the sessions)
Prior to data collection, a standard-
Exercise and The listed interventions Strengthening exercises for the upper-
ized baseline examination form was conditioning must both be quarter muscles
developed to gather consistent infor- received in at least Strengthening exercises for the neck
mation on all patients. Key examina- 50% of the sessions. or deep neck flexor muscles
tion variables that were standardized Pain control The listed interventions Cervical spine mobilization
for collection on all patients are must both be Cervical range-of-motion exercises
shown in Table 1. A standardized received within the
form for recording interventions first 3 sessions;
used during each physical therapy immobilization with
a cervical collar or
session was developed to record similar device cannot
consistent intervention information. be used.
The categories of interventions re-
Headache The listed interventions Cervical spine manipulation or
corded and the operational defini- must all be received. mobilization
tions used are shown in Table 2. Strengthening exercises for the deep
Physical therapists working in partic- neck flexor muscles
ipating clinics attended at least 2 Strengthening exercises for the upper-
quarter muscles
training sessions conducted to famil-

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Treatment-Based Classification System for Patients With Neck Pain

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Figure.
Classification decision-making algorithm. MVA⫽motor vehicle accident, NDI⫽Neck Disability Index.

iarize the therapists with the stan- straints were placed on the content aware of the interventions and out-
dardized forms. The procedures or duration of treatment. After the comes and unaware of the judgments
used for examination items and the completion of therapy, examination of the first reviewer, classified a ran-
operational definitions of the inter- and intervention data were col- domly selected subset of 50 patients
ventions were reviewed. Interven- lected. For each patient, initial and to examine the interrater reliability
tions were discussed, but no explicit final scores on the NDI and pain rat- of the classification algorithm.
instruction in the classification pro- ings and the number of physical ther-
cess or clinical decision making was apy visits were obtained from the Interventions
provided. The purpose of the train- database. Prior to data collection, we defined
ing was to standardize data collec- the intervention components matched
tion procedures, not to standardize Patient Classification to each classification in the proposed
treatment decision making. Using the proposed classification sys- system on the basis of current evi-
tem, we developed an algorithm to dence when possible and standard
Data collection was conducted from prioritize the findings and place practice when necessary (Tab. 2). For
January to December 2004. During each patient into a classification cat- the mobility classification, evidence
this period, all new patients who egory on the basis of variables from supported defining the matched com-
were determined by the physical the baseline examination (Figure). A ponents as manual therapy (manipula-
therapists to have a primary com- classification category was assigned tion or mobilization of the cervical or
plaint of neck pain were evaluated for each patient by a reviewer who thoracic spine) and strengthening ex-
with the standardized form, and in- was unaware of the interventions ercises for the deep neck flexor mus-
terventions were recorded with the used and the patient’s clinical out- cles.26,27,49 Because we anticipated
standardized categories. No con- comes. A second reviewer, also un- rapid improvement in this classifica-

516 f Physical Therapy Volume 87 Number 5 May 2007

 Treatment-Based Classification System for Patients With Neck Pain

tion, these interventions had to be re- Data Analysis compared the numbers of sessions
ceived within the first 3 sessions. High- To permit the evaluation of clinical for patients receiving matched treat-
quality evidence is lacking in the outcomes, the analysis included only ments and those receiving non-
literature for the centralization clas- patients with at least 2 physical ther- matched treatments by using inde-
sification. Common practice includes apy visits. The interrater reliabilities pendent t tests. We compared
either cervical traction or neck re- of the classification algorithm and clinical outcomes (changes in NDI
traction exercises to promote cen- the treatment-matching criteria were and pain rating scores) by using sep-
tralization24,50 –54; therefore, these in- examined by calculating percentage arate analysis of covariance proce-
terventions were considered matched agreement and kappa coefficients dures with covariates of age, sex, du-
components. More specifically, trac- with 95% confidence intervals (CIs) ration of symptoms, classification
tion (manual or mechanical) had to between the judgments of the first category, and baseline score for the

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be received in at least 50% of the ses- and second reviewers. Equal cate- outcome measure. We also com-
sions or retraction exercises had to gory weights were used in the calcu- pared the proportions of patients in
be received in at least 50% of the lation of the kappa coefficients. the matched and nonmatched
sessions to be considered matched groups achieving the minimum de-
components. Descriptive statistics were calculated tectable change (MDC) for the NDI
for the baseline characteristics of by using chi-square tests. The MDC
On the basis of evidence regarding in- each classification category, includ- represents the smallest amount of
terventions for patients with chronic ing, for continuous variables, means change in an outcome measure that
neck pain, strengthening exercises for with standard deviations or medians likely reflects true change rather
both the upper-extremity muscles and with ranges of scores and, for cate- than measurement error alone.58 The
the cervical or deep neck flexor mus- gorical variables, frequencies and MDC for the NDI has been defined as
cles were considered matched com- percentages. Differences among clas- 8 points.47 We categorized any pa-
ponents for the exercise and condi- sification categories were examined tient with a change score of 8 or
tioning classification.32,36,55,56 Each by analysis of variance, Kruskal- greater as achieving the MDC,
component had to be received in at Wallis, or Pearson chi-square tests as whereas patients with a change
least 50% of the sessions. For the pain appropriate. Clinical outcomes were score of 8 or less were categorized as
control classification, cervical mobili- calculated for each patient by com- not achieving the MDC. For the ex-
zation and ROM exercises for the puting the amounts of change in amination of the MDC, we excluded
cervical spine were supported by pain rating and NDI scores. To ex- patients with a baseline NDI score of
evidence37–39 and were considered amine the outcomes of the classifica- less than 10%. We also calculated the
matched components. Because of the tion categories, we compared clini- clinical outcomes for patients receiv-
acute nature of the condition, each cal outcomes, including the number ing matched treatments and those
component had to be received within of sessions, by using Kruskal-Wallis receiving nonmatched treatments
the first 3 sessions. For the headache tests, and we compared changes in within each category, and we report
classification, evidence supported cer- pain rating and NDI scores across clas- these values descriptively. Statistical
vical mobilization or manipulation and sification categories by using analysis comparisons were not performed
strengthening exercises for the upper- of covariance with the age, sex, and because of inadequate power.
quarter and deep neck flexor muscles baseline scores of the dependent vari-
as matched components.41,57 All 3 ables serving as covariates. Results
components had to be received to be A total of 297 patients with neck
considered matched. The interventions received by each pain were evaluated during the
patient were examined by an inves- study. Fifteen patients received only
To examine the interrater reliability tigator unaware of the outcome of 1 session and were not included in
of determining treatment matching, treatment. On the basis of the neces- the analysis. Eight patients classified
another reviewer, unaware of the sary components for each classifica- as having noncervicogenic head-
judgments of the first reviewer, was tion category (Tab. 3), each patient’s aches were not included, leaving 274
provided with the interventions used treatment was categorized as being patients for analysis. The character-
for the randomly selected subset of matched or not matched to the pa- istics of these patients are shown in
50 patients mentioned above. This tient’s classification. Treatment was Table 3. Fifty patients (age [X⫾SD]⫽
additional reviewer rated the treat- categorized as being matched if each 44.2⫾12.7 years; 78% women) were
ment procedures as being matched of the necessary components for the randomly selected for the interrater
or not matched to the classification patient’s classification was received reliability analysis. The selected pa-
categories. over the course of treatment. We tients did not differ from the non-

May 2007 Volume 87 Number 5 Physical Therapy f 517

Treatment-Based Classification System for Patients With Neck Pain

Table 3.
Comparison of Baseline Characteristics Among Classification Categories

Characteristica All Subjects Mobility Centralization Exercise and Pain Control Headache
(nⴝ274) (nⴝ48) (nⴝ95) Conditioning (nⴝ16) (nⴝ25)
(nⴝ90)
Age, y, X (SD) 44.4 (16.0) 37.0 (11.6)b 43.9 (13.7)b 50.5 (18.6)c,d 39.3 (16.2) 41.2 (14.2)
% Women 73.7 70.8 73.7 70.0 87.5 84.0
b,d,e c,f c,e,f b,d,e
Symptom duration, 48 d (1 d–24 y) 14 d (4–30 d) 78 d (7 d–20 y) 120 d (7 d–24 y) 11.5 d (1–21 d) 45 db (6 d–3 y)
median (range)
% of subjects with prior 45.4 39.6 45.3 42.7 37.5 72.0

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history of neck
pain
% of subjects reporting
the following
aggravating factor:
Looking up (n⫽254) 44.9 37.8f 51.8 41.2f 68.8b,c,e 30.4f
Looking down 48.6 51.1 52.9 40.5 62.5 47.8
(n⫽253)
Rotation (n⫽254) 66.8 62.2f 71.3f 62.4f 93.8b,c,d,e 56.5f
Overhead arm use 35.0 24.4 48.8 23.1 68.8 22.7
(n⫽237)
Flexion ROM, °, X (SD) 46.1 (15.1) 49.1 (14.9)f 45.9 (15.2) 46.0 (12.9)f 33.7 (17.8)b,c,e 48.7 (17.2)f
(n⫽259)
Extension ROM, °, 45.7 (16.5) 46.8 (17.3)f 46.3 (15.9) 46.1 (15.6)f 33.2 (21.8)b,c,e 48.2 (14.4)f
X (SD) (n⫽260)
Total rotation ROM, °, 111.7 (31.5) 116.7 (29.3)f 113.9 (28.6)f 110.6 (31.2)f 83.0 (42.6)b,c,d,e 116.0 (31.9)f
X (SD) (n⫽261)
Total side-bending 67.0 (22.0)f 71.0 (22.2)f 69.3 (19.3) 63.2 (22.3)f 51.9 (29.8)b,c,e 73.9 (20.2)f
ROM, °, X (SD)
(n⫽260)
% of subjects in whom
symptoms
increased with the
following ROM
(n⫽259):
Flexion 50.8 45.7f 53.8 42.9f 80.0b,c 58.3
Extension 51.4 54.3b,f 57.1b,f 36.1c,d,f 86.7b,c,d,e 54.0f
f b,e
Rotation 68.3 69.6 69.2 63.9 93.3 62.5f
Side bending 67.6 67.4 71.4 59.0e 66.7 83.3b
% of subjects showing
peripheralization
with the following
ROM (n⫽259):
Flexion 3.9 0d 11.0b,c 0d 0 0
d b,c,e d
Extension 5.8 0 14.3 2.4 0 0d
Rotation 6.2 0d 15.4b,c,e 1.2d 6.7 0d
d b,c d
Side bending 4.6 0 11.0 2.4 0 0
a
ROM⫽range of motion.
b
Significantly different from exercise group.
c
Significantly different from mobility group.
d
Significantly different from centralization group.
e
Significantly different from headache group.
f
Significantly different from pain control group.

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 Treatment-Based Classification System for Patients With Neck Pain

Table 4.
Comparison of Clinical Outcomes Among Classification Categoriesa

Outcome All Mobility Centralization Exercise and Pain Headache

Subjects (nⴝ48) (nⴝ95) Conditioning Control (nⴝ25)
(nⴝ274) (nⴝ90) (nⴝ16)
No. of therapy visits 5.6 (3.7) 5.0 (3.4)b 5.7 (3.5) 5.7 (3.6) 8.2 (5.8)c 4.8 (2.6)
b b b c,d,e,f
NDI (initial) 35.7 (17.0) 32.9 (13.8) 37.6 (16.4) 30.8 (15.5) 63.8 (13.5) 33.8 (15.1)b
Pain rating (initial) 5.2 (2.4) 4.9 (2.2)b 5.3 (2.5)b 4.8 (2.3)b 7.9 (1.5)c,d,e,f 5.3 (2.7)b
NDI (final) 23.2 (16.5) 18.2 (14.2)b,d 27.0 (17.8)c,f 19.5 (13.7)b,d 34.5 (20.9)c,f 24.4 (16.1)

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Pain rating (final) 3.8 (2.8) 2.6 (2.1) 3.6 (2.6) 3.7 (2.3) 3.7 (2.3) 3.8 (2.8)
d b,c b d,e,f
Change in NDI 12.7 (13.9) 15.0 (13.2) 10.6 (12.5) 11.3 (12.5) 29.6 (21.0) 10.4 (12.3)b
Change in pain rating 1.9 (2.5) 2.3 (2.2)d 1.7 (2.2)b,c 1.7 (2.6) 4.2 (2.6)f 1.5 (3.0)
% of subjects achieving 60.9 66.7 60.0 56.7 81.3 56.0
minimum detectable
change in NDI
a
Data are reported as mean (SD) unless otherwise indicated. NDI⫽Neck Disability Index.
b
Significantly different from pain control group.
c
Significantly different from mobility group.
d
Significantly different from centralization group.
e
Significantly different from headache group.
f
Significantly different from exercise group.

selected patients with respect to age, Table 5.

sex, baseline NDI and pain rating Comparison of Baseline Characteristics and Clinical Outcomes for Patients Receiving
scores, duration of symptoms, or Treatments Matched to Their Classifications and Patients Receiving Treatments Not
prior history of neck pain (P⬎.05). Matched to Their Classificationsa
The percentage agreement between Characteristic or Patients Receiving Patients Receiving
raters for classification judgments for Outcome Matched Treatments Nonmatched
these 50 patients was 96% (kap- (nⴝ113) Treatments (nⴝ161)
pa⫽.95, 95% CI⫽0.87–1.0). One ran- Age, y, X (SD) 44.7 (15.2) 43.8 (16.5)
domly selected patient was classified % women 74.3 73.3
as having noncervicogenic head-
Symptom duration, median 46 d (1 d–24 y) 48 d (4 d–12 y)
aches, leaving 49 patients for the ex- (range)
amination of treatment-matching
% of subjects with prior 40.7 48.1
judgments. The percentage agree-
history of neck pain
ment between raters was 98% (kap-
pa⫽.96, 95% CI⫽0.88 –1.0). No. of therapy visits 6.3 (3.6) 5.2 (3.7)
NDI (initial) 37.8 (18.3) 34.4 (15.9)
The centralization category had the Pain rating (initial) 5.2 (2.5) 5.2 (2.4)
largest number of patients (n⫽95,
NDI (final) 21.4 (16.4)b 24.4 (16.6)b
34.7%); next were the exercise and
conditioning (n⫽90, 32.8%), mobil- Pain rating (final) 2.8 (2.3)b 3.6 (2.5)b
ity (n⫽48, 17.5%), headache (n⫽25, Change in NDIc 16.4 (15.3)b 10.1 (12.2)b
9.1%), and pain control (n⫽16, Change in pain ratingc 2.3 (2.6)b 1.6 (2.4)b
5.8%) categories. The baseline char-
% of subjects achieving 72.5b 53.8b
acteristics for these categories are minimum detectable
shown in Tables 3 and 4. Patients in change in NDI
the exercise and conditioning cate- a
Data are reported as mean (SD) unless otherwise indicated. NDI⫽Neck Disability Index.
gory tended to be older and, along b
Significant difference between the groups (P⬍.05).
c
with those in the centralization cat- Change scores were adjusted for age, sex, duration of symptoms, and baseline pain and disability
scores.

May 2007 Volume 87 Number 5 Physical Therapy f 519

520 f
Table 6.
Clinical Outcomes Within Each Classification Category for Patients Receiving Matched and Nonmatched Interventionsa

Physical Therapy
Characteristic Mobility Centralization Exercise and Pain Control Headache
of Outcome Conditioning

Matched Nonmatched Matched Nonmatched Matched Nonmatched Matched Nonmatched Matched Nonmatched

No. of patients 18 30 56 39 26 64 10 6 3 22

Volume 87
Age, y, X (SD) 38.8 (10.9) 35.9 (12.1) 44.6 (13.0) 43.0 (14.9) 53.0 (17.1) 49.5 (18.9) 38.4 (19.5) 40.8 (9.6) 33.0 (6.0) 40.4 (13.5)

% women 72.2 70.0 67.9 82.1 76.9 67.2 100 66.7 100 81.8

No. of therapy 4.9 (2.3) 5.0 (4.0) 6.0 (3.3) 5.4 (3.8) 6.0 (3.3) 5.4 (3.8) 9.6 (5.9) 5.8 (5.3) 5.0 (1.7) 4.8 (2.7)

Number 5
visits

NDI (initial) 34.1 (10.9) 32.2 (15.4) 37.7 (17.9) 37.4 (14.1) 29.7 (16.0) 31.3 (15.4) 65.0 (11.1) 61.8 (17.7) 33.0 (23.6) 34.0 (13.7)

Pain rating 5.1 (2.0) 4.7 (2.3) 5.0 (2.4) 5.7 (2.6) 4.1 (2.2) 5.0 (2.3) 8.2 (1.8) 7.3 (0.82) 5.3 (4.4) 5.3 (2.4)
(initial)

NDI (final) 15.9 (11.7) 19.5 (15.5) 24.8 (18.0) 30.0 (17.2) 15.6 (12.4) 21.1 (14.0) 28.2 (18.0) 45.0 (22.6) 18.0 (17.4) 25.3 (16.1)

Pain rating 2.1 (1.8) 2.9 (2.2) 3.2 (2.4) 4.2 (2.7) 2.7 (2.4) 3.3 (2.2) 2.9 (1.4) 5.0 (3.0) 2.0 (2.0) 4.1 (2.8)
(final)

Change in NDIb 18.6 (13.1, 24.1) 12.8 (8.5, 17.0) 13.5 (10.3, 16.6) 7.4 (3.4, 11.0) 15.0 (10.7, 19.2) 9.8 (7.1, 12.5) 36.9 (23.0, 50.9) 17.3 (⫺1.6, 36.2) 22.3 (6.2, 38.3) 8.8 (3.3, 14.4)
(95% CI)

Change in pain 3.0 (2.1, 3.9) 1.9 (1.2, 2.5) 2.0 (1.4, 2.5) 1.3 (0.66, 2.0) 2.0 (1.1, 2.8) 1.5 (1.0, 2.1) 5.3 (3.7, 6.9) 2.4 (0.23, 4.5) 4.2 (0.55, 7.8) 1.2 (⫺0.10, 2.4)
Treatment-Based Classification System for Patients With Neck Pain

ratingb
(95% CI)

% of subjects 66.7 66.7 71.4 43.6 61.5 54.7 90.0 66.7 100 50.0
achieving
minimum
detectable
change
in NDI
a
Data are reported as mean (SD) unless otherwise indicated. CI⫽confidence interval, NDI⫽Neck Disabaility Index.
b
Change scores were adjusted for age, sex, duration of symptoms, and baseline pain and disability scores.

May 2007
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 Treatment-Based Classification System for Patients With Neck Pain

egory, had longer symptom dura- for patients receiving matched and next. The results of the present study
tions. Patients in the pain control cat- nonmatched interventions within showed that the decision-making al-
egory had less ROM and were more each classification category is shown gorithm could be applied consis-
likely to experience symptom aggra- in Table 6. tently by different examiners consid-
vation with ROM. Patients in the cen- ering the same patient data (kappa
tralization category were most likely Discussion value for interrater agreement⫽.95),
to experience peripheralization with Physical therapists working in out- but only additional research can eval-
ROM. Patients in the pain control patient settings frequently treat pa- uate and refine the algorithm so that
category had higher baseline NDI tients with neck pain.59 The progno- it results in the best outcomes for
and pain rating scores (Tab. 4). Pa- sis for neck pain is not consistently patients. Additional research is also
tients in the centralization category good, with many people experienc- necessary to further examine the

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experienced fewer changes in NDI ing persistent pain and disability,60 overall reliability of the classification
and pain rating scores than those in even with physical therapy interven- system, not just the proposed
the mobility and pain control tion.3,61 Experience with the treat- algorithm.
categories. ment of patients with low back pain
has shown that developing guide- In order to maximize clinical utility,
Overall, 113 patients (41.2%) re- lines for classifying patients into classification systems need to be as
ceived interventions that were smaller subgroups based on clinical comprehensive as possible. The sys-
matched to the prespecified treat- characteristics and matching these tem examined in the present study
ment components, whereas 161 classifications to management strate- primarily addresses patients with
(58.8%) received nonmatched inter- gies likely to benefit them can im- neck pain and associated symptoms
ventions. The pain control category prove the outcomes of care provided (eg, headache and upper-extremity
had the highest percentage of pa- by physical therapists.18,20,21 Classifi- symptoms) believed to be attribut-
tients receiving matched interven- cation strategies also can increase able to dysfunctions of the cervical
tions (62.5%); next were the central- the power of clinical research,19 en- spine. The decision-making process
ization (58.9%), mobility (37.5%), hancing efforts to develop evidence for screening patients for non-
exercise and conditioning (28.9%), that can favorably affect clinical mechanical etiologies is not ad-
and headache (12.0%) categories. practice by identifying evidence- dressed in this system. Patients with
There were no baseline differences based practice patterns for particular neck pain referred from other struc-
between patients receiving matched subgroups of patients.62 tures (eg, temporomandibular joint)
interventions and patients receiving are not considered in this system.
nonmatched interventions for age, Developing a classification structure For patients with neck pain and as-
sex, duration of symptoms, and NDI requires the consideration of numer- sociated symptoms, the system is de-
and pain rating scores (Tab. 5). After ous attributes. Classification catego- signed to assign a specific category
adjustment for all covariates, pa- ries that are both mutually exclusive to each patient. The literature sup-
tients receiving matched interven- and comprehensive must be de- ports the notions that distinctions
tions showed greater changes in scribed. Although aspects of a pa- between patients with acute symp-
both NDI scores (mean difference tient’s clinical presentation typically toms and patients with chronic
for adjusted scores⫽5.6, 95% can fit several categories, a useful symptoms63,64 and between patients
CI⫽2.6 – 8.6) and pain rating scores classification system must be able to with and patients without signs and
(mean difference for adjusted prioritize these findings to permit symptoms associated with nerve
scores⫽0.74, 95% CI⫽0.21–1.3) physical therapists to make clinical root compression65 are important for
(Tab. 5). Nine patients (4 receiving decisions and researchers to define treatment decision making. Patients
matched interventions and 5 receiv- homogeneous subgroups for future with acute, traumatic onset (eg,
ing nonmatched interventions) had studies. In this article, we have de- whiplash injury)66 and those with
baseline NDI scores of less than 10% scribed specific criteria for mem- headache as a predominant symp-
and were excluded from the exami- bership within each classification tom41 also may represent distinct cat-
nation of achieving the MDC for the category and a decision-making al- egories of patients. Further research
NDI. Among patients receiving gorithm to prioritize these criteria is needed to determine whether ad-
matched interventions, 72.5% (Figure). Using our mostly clinical ditional subgroups should be added
achieved the MDC; in comparison, experience, we prioritized findings to the system.
53.8% of patients receiving non- associated with the pain control clas-
matched interventions did so sification first and findings associated Ultimately, the most important at-
(P⫽.002). Descriptive information with the centralization classification tribute of a classification system is its

May 2007 Volume 87 Number 5 Physical Therapy f 521

Treatment-Based Classification System for Patients With Neck Pain

ability to improve patient outcomes The most common classification not to emphasize strengthening in-
when it is used for treatment deci- among the patients in the present terventions. As expected, patients in
sion making in clinical practice. Re- study was centralization. This classi- the pain control classification re-
search must demonstrate that out- fication was identified by the pres- ported more pain and disability and
comes are better when patients ence of signs of nerve root com- greater ROM restrictions, were more
receive interventions matched to pression or symptoms distal to the likely to report aggravation of symp-
their classifications than when they elbow. Patients in this classifica- toms with various movements than
receive nonmatched interventions. tion also were more likely to show patients in other classifications at
The design of the present study does peripheralization with active ROM at baseline, and reported the most
not permit any conclusions about the baseline examination, a finding change in pain and disability with
the effectiveness of this system for that may be useful to consider as a treatment.

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improving clinical outcomes to be classification criterion for this sub-
drawn. The necessary research de- group of patients. Overall, this clas- The design of the present study has
sign to eventually document the su- sification was associated with fewer several limitations and potential for
periority of any decision-making sys- changes in NDI and pain rating bias in the results. Patients were not
tem is a randomized trial.67 In the scores than other classifications, a randomly assigned to receive matched
present study, we used a prospec- finding that is consistent with the or nonmatched treatments. Despite
tive, observational design as a pre- poorer prognosis reported for peo- statistical control for baseline vari-
liminary step toward this end. The ple with radicular findings in other ables such as age, sex, duration of
results of the present study showed reports.14,68 The exercise and condi- symptoms, and baseline pain or dis-
an association between receiving tioning classification was the second ability scores, important disparities
matched treatments and experienc- most common classification and had between patients receiving matched
ing greater reductions in pain and the second lowest rate of matched treatments and patients receiving
disability. These findings encourage interventions. The exercise and con- nonmatched treatments within each
further research examining the ef- ditioning classification includes classification may have contributed
fect of classification methods on clin- older patients with more chronic to the observed differences. There-
ical outcomes for patients with neck symptoms than the other classifica- fore, the present study cannot pro-
pain. tions. Matched interventions, as indi- vide evidence for the predictive va-
cated by evidence in the literature, lidity of the proposed system. Only a
We examined the overall clinical out- focus on strengthening the upper- study randomizing patients to re-
comes of patients receiving treat- quarter and cervical muscles. The ceive matched or nonmatched treat-
ments that were judged to be low rate of matched interventions in ments could provide such evidence.
matched or not matched to their this classification may indicate a ten-
classifications. Because of the small dency for therapists not to empha- Another limitation is the lack of stan-
numbers of patients in some classifi- size strengthening in this subgroup dardization of the intervention pro-
cations, we did not separately exam- of patients. Patients in the mobility cedures. It was left to the physical
ine the association between clinical classification tended to experience therapists in the present study to cat-
outcomes and receiving matched the most change in pain and disabil- egorize the interventions that were
treatments within each classification ity, consistent with literature sup- provided. There were likely a wide
category. The intent of a classifica- porting a better prognosis for pa- variety of specific procedures in-
tion system is to define combinations tients with acute neck pain but cluded within many of the catego-
of treatments that uniquely benefit without radicular symptoms.11,14 ries, such as upper-extremity strength-
patients with certain characteristics. ening exercises. We attempted to
If all patients with neck pain are Fewer patients were classified into record only the basic category of
equally likely to receive benefit from the headache or pain control classi- each treatment, not specific tech-
the same combinations of treat- fications. In the headache classifica- niques or parameters. We did not
ments, then classification becomes tion, very few patients received record the dosage or intensity of ex-
unnecessary. Further research is matched interventions (deep neck ercise or the specific manual tech-
needed to examine the relationship flexor strengthening, cervical spine niques used. On the basis of research
between clinical outcomes and re- manipulation or mobilization, and on patients with low back pain sug-
ceiving matched treatments within upper-extremity strengthening). As gesting better outcomes with more
each classification category. indicated above, this finding may standardized interventions than with
represent a tendency among the therapist-selected interventions,69 we
therapists participating in this project believe that the presence of associa-

522 f Physical Therapy Volume 87 Number 5 May 2007

 Treatment-Based Classification System for Patients With Neck Pain

tions between categories of treatment 3 Di Fabio RP, Boissonnault W. Physical 19 Childs JD, Fritz JM, Flynn TW, et al. Vali-
therapy and health-related outcomes for dation of a clinical prediction rule to iden-
and outcomes for subgroups of pa- patients with common orthopaedic diag- tify patients with low back pain likely to
tients in the present study suggests the noses. J Orthop Sports Phys Ther. 1998; benefit from spinal manipulation. Ann
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78:1346 –1351.
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Proposal of a classification system for pa-
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for patients receiving physical ther- Effectiveness of physical therapy for pa-
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26 Cleland J, Childs JD, Fritz JM, et al. Devel-
associations between receiving inter- 11 Cote P, Cassidy JD, Carroll L. The factors opment of a clinical prediction rule for
associated with neck pain and its related
ventions matched to the system and guiding treatment of a subgroup of pa-
disability in the Saskatchewan population. tients with neck pain: use of thoracic
better clinical outcomes. These pre- Spine. 2000;25:1109 –1117. spine manipulation, exercise, and patient
liminary results suggest opportuni- 12 Ernst CW, Stadnik TW, Peeters E, et al. education. Phys Ther. 2007;87:9 –23.
Prevalence of annular tears and disc her-
ties for further research. 27 Hoving JL, Koes BW, de Vet HCW, et al.
niations on MR images of the cervical Manual therapy, physical therapy, or con-
spine in symptom free volunteers. Eur J tinued care by a general practitioner for
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14 Borghouts JA, Koes BW, Bouter LM. The therapy and physiotherapy for persistent
Brennan provided facilities/equipment. clinical course and prognostic factors of back and neck complaints: subgroup anal-
non-specific neck pain: a systematic re- ysis and relationship between outcome
This study qualified for exempt review by the view. Pain. 1998;77:1–13. measures. J Manipulative Physiol Ther.
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15 Fritz JM, George S. The use of a classifica-
Health Care. tion approach to identify subgroups of pa- 29 Tseng YL, Wang WT, Chen WY, et al. Pre-
tients with acute low back pain: inter-rater dictors for the immediate responders to
This study was supported by a grant from reliability and short-term treatment out- cervical manipulation in patients with
the Deseret Foundation. comes. Spine. 2000;25:106 –114. neck pain. Man Ther. 2006;11:306 –315.
This article was received July 7, 2006, and was 16 Spitzer WO. Scientific approach to the as- 30 Werneke M, Hart DL. Centralization phe-
sessment and management of activity- nomenon as a prognostic factor for
accepted January 8, 2007. related spinal disorders: a monograph for chronic low back pain and disability.
clinicians— diagnosis of the problem (the Spine. 2001;26:758 –765.
DOI: 10.2522/ptj.20060192 problem of diagnosis). Spine. 1987; 31 Werneke M, Hart DL. Discriminant validity
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