Multidisciplinary rehabilitation for chronic back pain in an outpatient setting: a controlled randomized trial

European Journal of Pain (1997) 1: 279-292

Multidisciplinary rehabilitation pain in an outpatient setting: randomized trial S. Keller”,“, S. Ehrhardt-Schmelzerb,

for chronic a controlled

C. Herda”, S. Schmid”

back

and H-D. Baslerc

“Cancer Prevention Research Center, &iversity of Rhode Island, USA bPROMOTI@ Health Center, Gtittingen, Germany “Medical Center for Methodology and Health Research, Institute for Medical University, Marburg, Germany

Psychology,

Philipps-

Based on existing models for pain chronicity and effective &atment strategies for patients with chronic low back pain, a multidisciplinary rehabilitation programme for an outpatient group setting was developed. The main treatment components address the patient’s physical functional capacity (functional restoring), cognitive and affective processes (pain management strategies), and behavioural and ergonomical aspects (back school elements). Short-term (immediately after intervention) and long-term effects (at 6-months follow-up) of the intervention were assessed in a randomized controlled study. Dependent variables were pain measures, functional capacity, disability, muscular strength and endurance, pain and posture-related self-efficacy, attitudes, depression, wellbeing, behavioural habits and posture assessed by a standardized behavioural observation method. Immediately after the intervention, patients in the treatment group (n = 36) showed significant improvement over patients in the control group (n =29) in all variables except depression and muscular strength and endurance. At 6-months follow-up, compared to pretreatment scores, patients continued to show beneficial effects in pain intensity and frequency, posture, posture-related self-efficacy and well-being. In contrast to posttreatment results, there were also significant improvements in strength and endurance. Overall results testify to the effectiveness of the intervention programme. Future studies (with larger sample sizes) should aim at a further improvement of functional capacity and disability perception, an analysis of differential treatment effects, and strategies for an improved long-term maintenance of the changes induced by the programme.

INTRODUCTION low back pain continues to be one of the major health problems in the Western world, both in terms of suffering and economical costs. For the United States alone, the cost for treatment and compensation in 1990 added up to an

Chronic

Paper received 8 July 1997 and accepted in revised form 4 November 1997. Correspondence to: H-D. Basler, Institute for Medical Psychology, Philipps University of Marburg, Bunsenstr. 3, 35033 Marburg, Germany. 1090-3801/97/010279+14$12.00/0 0 1997 European Federation

of Chapters

of the International

estimated 50-100 billion dollars (Frymoyer & Cats-Baril, 1991), mainly caused by a comparatively small proportion of those who ever experience episodes of back pain (Quebec Task Force Report, 1987). As Linton (1994) points out, the majority of these are generally due to compensation for long-term sick absenteeism.In many European countries with a more liberal health care and compensation system, relative expenditures may be even higher. In view of the individuals suffering from chronic pain and the high costs for society, it is obvious that efforts should be undertaken to identify variables that Association

for the Study

of Pain

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contribute to chronicity, and to develop effective and cost-effective interventions aiming at a prevention of progression. Basler (1994) identifies four important factors contributing to pain chronicity, as described below. Biomechanical

ETAL.

psychosocial factors and the patient’s interaction with his or her work environment. The correlation of personal distress and pain could be accounted for by a diathesis-stressmodel. Given a genetic predisposition, continuous stress can result in a long-term increasein muscular tonus and in increasednociceptor activity (Flor, 1991).

stress Operant

conditioning

mechanisms

Biomechanical stress of the back can be caused by heavy work such as lifting (Garg & Moore, Operant mechanisms can stabilize chronic pain 1992), long-term exposure to vibration (Wilder, in various ways. The actual experience of acute 1993),or sedentaryor monotonous job functions pain has an important alarm function and helps (Kamwendo et al., 1991;Rundcrantz, 1991).The a person to withdraw from a harmful situation. biomechanical model of chronic pain assumesa The cognitive anticipation of pain, on the other relationship between external strain, body pos- hand, may elicit behaviour that is thought to be ture, muscle activity and intravertebral pressure ‘detrimental to recovery. People who suffer from (Dolce & Raczynski, 1985). According to this pain often fear that physical activity may increase model, chronic pain is a result of an abnormal their suffering, and therefore, avoid being active. pattern of paraspinal activity caused by over- In addition, avoidance behaviour may be reexertion and poor postural habits. It is believed inforced by physicians who prescribe bed rest that such irregular muscle activity provides ab- and inactivity for the treatment of acute pain normal support for the spine, which in turn conditions. In persons with a prolonged history becomes unstable. The instability of the spine of pain, inactivity can lead to physical problems enhances the possibility of impingement upon such as a decreaseof bone density (Hansson et nerve endings and abnormal pressure on the al., 1975),or a loss of muscle strength (Bieringdiscs, and thereby produces pain (Nachemson, Sarrensenet al., 1994). 1987). An additional risk factor is physical inFrom a psychological perspective, avoidance activity, which leads to muscular deconditioning behaviour results in a decreaseof activities that and a loss of muscle strength (Chaffin & Ashtonare incompatible with pain, and thereby, to a Miller, 1991; Biering-Ssrensen et al., 1994). decrease in quality of life and personal wellbeing. Long-term effects can be social withdrawal, decreased self-efficacy and depression. Psychosocial stress Avoidance behaviour may be primarily caused In a recent study, Croft et al. (1996) reported by fear of pain (McCracken et al., 1993) and that psychological distress can be a predictor for can generalize to fear of work-related activities the subsequentonset of low back pain episodes (Waddell et al., 1993) or fear of movement or in individuals without back pain within 1 year. (re)injury (Kori et al., 1990).Vlaeyen et al. (1995) They estimate that the proportion of new pain found that fear of movement is highly correlated episodesattributable to psychological factors in with catastrophizing cognitions, dysphoric mood the general population is 16%. More specific and behavioural performance, which in turn staforms of distress,such asjob dissatisfaction, may bilize pain chronicity. be even more important for pain chronicity than general distress. On the basis of several studies, Weiser and Cedraschi (1992) found that work Dysphoric mood satisfaction and social support at work could There is extensive evidence for a covariation predict the occurrence of low back pain. Fryof chronic pain and depression. Basler (1994) moyer (1992) concludes that continuing disability, in particular, may be determined by concludes that depression can be seenrather as European

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a contributing factor to the processof chronicity than as a predisposing factor. Turk et al. (1995) point out that the severity of psychological distress is not a function of physical pain alone; it is mediated by the way patients perceive their pain. Mechanisms that contribute to the depressive state of chronic pain patients can be social withdrawal (caused by avoidance behaviour and inactivity), or a generalloss of positive reinforcement (Fordyce, 1976), as well as inadequate cognitive coping strategies and attributional styles that lead to helplessf&ss and depression(Seligman, 1975). It is obvious that various inter-related factors contribute simultaneously to the process of chronicity. Turk and Okifuji (1996)conclude that biomechanical factors are more relevant to the acquisition of pain, whereas psychological and behavioural factors help maintain and exacerbate pain, disability and psychological distress. Since multiple factors are involved in the development of a chronic low back pain syndrome, it 4s not surprising that comprehensive treatment approachesincorporating behavioural, biomedical, psychological, physical and social components have not only proven to be most effective (Flor et al., 1992),but are also cost-effective (Turk & Okifuji, 1996). Based on the available evidence, three treatment components can be identified as crucial in the prevention and treatment of chronic back pain: Physical

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exercise

According to Foster and Fulton (1991), improvement of muscular strength, muscular endurance and flexibility, as well as overall fitness, are important components in the prevention and treatment of chronic low back pain. In a recent meta-analysis, Faas (1996) found that extension and fitness exercisesare effective in the treatment of chronic pain. Moreover, there is increasing evidencethat for chronic pain patients, intensive exercise may be even more appropriate than moderate training (Manniche et al., 1991;Pfmgsten et a/., 1997). Little is known about differential effects of exercisefor men and women or for certain occupational subgroups (Hansen et

al., 1993).Nevertheless,physical training can be considered as an important and effective option in the treatment of low back pain, especially when its implementation is supported by operant management strategies (Geiger et al., 1992). From a cognitive perspective,intensive exercise can be seenas a confrontation with fear beliefs of the patient (Waddell et al., 1993; Waddell & Turk, 1992). Successful exposure to the feared stimulus may lead to reattributions and to an increase in perceived behavioural control and self-efficacy (Bandura, 1977).

Training living

of posture

and activities

of daily

Back schools have beenwidely offered, especially in the context of primary or secondary prevention. Basic elements of theseprogrammes are usually information on back pain and posture, training of activities of daily living, ergonomic evaluation of the workplace and motivation to increase physical activity. It is assumed that a training in good postural habits and adequate performance of activities of daily living lead to improved muscular coordination and a stable support of the spine. This may contribute to a decreaseof intradiscal pressure, which in turn reduces the risk of spinal injury (Nachemson, 1987). In addition, ergonomic evaluation of the environment at work and at home is considered to be a precondition for the reduction of biomechanical stress. Reviews of the literature indicate that back schools in primary and secondary prevention show hardly any impact when they are offered as a sole treatment (Nordin et al., 1992;Turner, 1996). The same holds true for back education programmes for chronic pain patients, which provide information alone (Cohen et al., 1994). However, if back schools are offered as a component of a comprehensive programme, they contribute significantly to the effect of the treatment (Linton et al., 1993;DiFabio, 1995).In the present authors’ opinion, such a comprehensive training improves self-efficacyand gives patients a better feeling of control, thus enabling a favourable outcome. European

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Pain management

Pain management strategies integrate various cognitive and behavioural techniques which, in combination, have been proven to be highly effective in the treatment of chronic pain (Turner, 1996). Elements of such training are relaxation techniques such as progressivemuscle relaxation (Turner, 1982) strategiesthat focus on adequate coping with pain, on a decreaseof maladaptive cognitions (Bradley, 1996), and on an increase of well-behaviours by using operant*o.nditioning procedures (Basler et al., 1993). Several studies clearly demonstrate that in comparison with control subjects, treated individuals consume less health care,are lessincapacitated, are more likely to return to work, and more often improve their well-being and their ability to manage their pain (Flor et al., 1992; Linssen & Spinhoven, 1992; Nicholas et al., 1992;Linton, 1993;Basler, 1997). Little is known, however, about the mechanisms that mediate the effect of cognitive-behavioural interventions. Perceived self-efficacy may be an important link betweenadequatecoping and pain experience (Bandura, 1977). An analysis of the literature shows that an increase in self-efficacy is highly correlated with improvements in pain tolerance (Bandura et al., 1987;Dolce, 1987;Litt, 1988), pain behaviour and disability (Dolce et al., 1986; Altmaier et al., 1993), and the use of adequate coping strategies (Jensenet al., 1991). Patients who increasetheir feeling of control over their pain and who feel efficacious with regard to the management of their physical functions should be able to counteract dysphoric mood and physical impairment (Turk & Okifuji, 1996). The aim of this study was to assessthe effects of a treatment programme including these three essentialtreatment components in an outpatient rehabilitation setting. METHODS The treatment

programme

A standardized multidisciplinary programme for the rehabilitation of patients suffering from chronic low back pain was developed.Each patient received both individual and group treatment alternately, in order to tailor the European

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programme to the specific needs of each participant. The programme consisted of 18 2-h group meetings (three per week) in addition to 18 individualized training sessions(two patients with one trainer) of 30 min duration in an outpatient setting. The treatment was offered by a multidisciplinary team of therapists including physicians and physiotherapists with previous training in pain management strategiesprovided by the senior author of this study. Therapists were closely supervisedby clinical psychologists, experiencedin pain management, to ensurestrict application of operant techniques for the modification of the patients’ behaviour. The intervention was conducted at the PROMOTIO@ Health Centre in Gottingen, Germany. The group treatment included: Education

The educational elements aimed primarily at a reconceptualization of the patients’ pain experience.Patients receivedinformation about the vicious circle of pain, avoidance, demoralization and dysphoric mood, and about how the different treatment methods would contribute to gradually gaining self-control over pain and pain-related behaviour. Active participation in the treatment through engaging in group discussions, physical activity and homework assignmentswas strongly encouraged. Furthermore, patients received information about types and effects of pain medication. Relaxation

Patients learned how to control their physical responseto pain as a stressor,such as increased muscle tension and psychophysiological arousal, with the aid of progressive muscle relaxation according to Jacobson (1938). A relaxation tape for home practice was provided. By gradually shortening the relaxation instructions and by showing ways of applying relaxation in real life situations, the authors sought to encourage the continued use of relaxation in everyday life. As a second step, patients were taught how to use imagery techniques and visualization to distract themselves from pain, and to further improve their relaxation skills.

MULTIDISCIPLINARY

Pleasant

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activity

scheduling

and distraction

Participants

On an operant basis, special effort was undertaken to direct patients’ attention away from activities in which they were restricted to those which they could enjoy. A training that offered a variety of perceptional experiences served to elicit feelings of pleasure. Activity goals were scheduled, and pleasurable activities were reinforced in subsequent sessions. In addition, specialemphasis was put on the application of distraction techniques. Patients learned how to focus their attention either on mental ur on physicalactivities in order to direct their attention away from the present experienceof pain. Training

of posture

and physical

exercise

A curve of the spine with a lumbar as well as a cervical lordosis (the upright position), is estimated to be beneficial in terms of a balanced distribution of pressure in the lumbar discs (Brtigger, 1980; Nachemson, 1987). For athis reason, participants were taught to adapt progressively to an upright position. They were encouragedto maintain this position while performing various activities such as sitting in front of a computer screen,sweeping the floor, lifting heavy loads, or kneeling on a carpet. The individual sessionsfocussed on exercisesaimed at stretching and strengthening the muscles, while paying special attention to each patient’s specific needs. In addition, an evaluation of the environment at home and at the worksite was carried out for every participant. Problem areas were highlighted and improvements suggested. TABLE

1. Description

of the sample

before

treatment

Treatment

Age

Gender Proportion of patients with pain for longer than 6 months Proportion of patients with constant or daily pain in the last 2 weeks SD, standard

deviation;

n, sample

Patients were eligible for inclusion in the study if: (1) they were given a diagnosis of chronic low back pain in accordance with the classification of the Quebec Task Force on Spinal Disorders (1987); (2) they had not participated previously in a pain management programme; (3) they were sufficiently fluent in German; and (4) they were able to attend therapy sessionson a regular basis in an outpatient setting. Consecutive low back pain patients who fulfilled the inclusion criteria were encouragedto provide informed consent in order to participate in the study. Those who did filled in self-report questionnaires and were interviewed for their pain history. Patients were allocated randomly to a treatment group or a waiting-list control group. Unfortunately, seven patients refused participation after being assignedto the control group. Since they did not provide informed consent, a comparison of this group and the 65 patients who signed up for the programme was not possible. The group treatment for the experimental subjects (n=36) was conducted in four subsequent groups, and individual sessions took place as explained above. Before the beginning of treatment, the experimental group and control group did not differ in sociodemographic variables, pain chronicity or frequency of pain episodes (Table 1). The average duration of pain was 9.6 years (SD =7.1) in the experimental group and 10.9 years (SD= 12.2) in the control group. Some of the patients were referred by physicians and some were self-selectedfor programme participation.

group

Control

group

Test of difference between groups

Mean=46.89 SD=12.25 n=35 Female =25 (74%) Male = 9 (26%) 30 (94%)

Mean=49.10 SD= 12.75 n=29 Female =20 (69%) Male=9 (31%) 25 (89%)

13 (37%)

16 (55%)

f(df=62)=0.71 n.s. X’(df=1)=0.16 n.s. x*(df=1)=0.39 n.s.

size; df, degrees

of freedom;

X*(df=1)=2.08 n.s.

n.s., not significant. European

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One patient did not finish the intervention course and seven patients did not participate at the 6-month follow-up. t-tests and x2 tests suggestedthat these patients did not differ in sociodemographic variables or psychological or physical measures at post-treatment assessment from those who completed the follow-up measures. Some patients failed to complete the entire set of questionnaires, so the sample size differs for different variables. Since the ethical committee did not consider it appropriate to withhold a psychological treatment deemedt&be effective, patients allocated to the control group received the same psychological treatment after termination of treatment in the experimental group. In consequence,no data of untreated controls are available at the third assessmentof the experimental subjects.

the current functional capacity expressed as a percentage(Raspe, 1993). Strength and endurance. Muscular strength and endurance were measured as maximum number of repetitions for four different exercises including: knee-bending,extension and bending of the trunk. Disability. The German version (Dillmann et al., 1994) of the Pain Disability Index (Tait et al., 1987) was used. The subject has to indicate,

on an 11-point scale,how much the pain disables him or her in seven areas of life (e.g.job, social activities, recreation). The authors of the German version report satisfactory psychometric properties with average internal consistency coefficients of 0.88 in several studies. Measures habits

Assessment

instruments ,

Pain measures

Frequency of back pain was assessedby a single item on a five-point scale (1 = ‘never’ to 5 = ‘always’). Pain frequency.

Typicalpain intensity. Typical pain intensity was rated on an 11-point scale (0 = ‘no pain’ to 10= ‘unbearable pain’).

Functional

measures

A 1Zitem questionnaire is used to measure the degree of perceived functional capacity (Kohlmann et al., 1992). The patient suffering from back pain rates his or her performance during common daily activities (internal consistency >0.85 in different studies, correlation with other rated disability >0.65). Sample items are ‘Can you wash and dry yourself from head to toe?’ ‘Can you run 100 m fast without stopping in order to catch a bus?’ Each item has to be answered either ‘Yes, without difficulty’ (=2 points), ‘Yes, but with some difficulty’ (= 1 point) or either ‘unable to do, or only able with help’ ( = 0 points). The actual sum (in case of no missing values) is divided by 24 and multiplied by 100 to get an estimate of

Functional

European

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of posture

and behavioural

Video-supported behavioural observation. For a period of 5 min, participants and controls had to demonstrate 13 activities including: sitting down, sitting, walking with a box, and putting down a box. Each sequencewas rated on a four-point rating scale reflecting the degree to which adequate posture and gait was expressed,including the position of the legs, knees, hips, pelvis, etc. The video ratings were performed by a physiotherapist who did not have previous contact with the subjects in the study, and who was blind with respect to treatment condition. The video rating has been shown to have satisfactory inter-rater reliability (intra-class correlations r = 0.70 or higher) and internal consistency (a = 0.91) (Basten & Basler, 1993).

Patients were asked to indicate on a six-point scale to what extent they habitually show each of seven back-health relevant behaviours. Examples ‘While sitting, I pay attention to the maintenance of an upright position’. The scalehas been shown to possesshigh internal consistency(LX= 0.76; Basler et al., 1993).

Behaviour

habits.

Measures

of cognitions

and mood

Posture related selfefficacy was assessedon a seven-point scale.Subjects rated how confident they were in their ability Posture-related self-efficacy.

MULTIDISCIPLINARY

REHABILITATION

to perform eight different tasks while maintaining a good body posture (e.g. ‘I am confident I will hold my back and shoulders upright while sitting’). The scalehas satisfactory psychometric properties (internal consistency CI= 0.85; Ridder, 1997).

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for the control group over a 3-month interval (Table 2).

Statistical

analyses

Statistical analyses were computed with the aid of the SPSS for Windows programme (Norusis, Pain-related self-efficacy. Pain-related self1993). A two-factor experiment with repeated efficacywas assessedon a seven-point scale. Sub- measurementson one factor was applied. Three jects indicated how confident they were in their assessments were taken: pre-treatment, postability to perform eight different task!%without treatment and at 6-months follow-up. Power anaany pain (e.g. ‘I am confident about walking for lysis showed that a minimum of 20 subjects per an hour without any pain’). Internal consistency group was required to secure large treatment has been reported to be satisfactory (a=O.87; effects (effect sizes >0.80) at an a-level ofpc0.05 Ridder, 1997). and a test power of p=O.80 (one-tailed tests). To control for differences in the initial values between the experimental and control groups, Attitudes towardposture andpain. Subjectshad continuous variables were first analysed by reto rate their agreement to 14 statements about peated one-way analyses of covariance (ANtheir attitudes towards adequateposture and pain COVAs) using the pretreatment scores as on a six-point scale (e.g. ‘I can prevent back covariate. Considering the number of dependent pain by taking an adequateposture.‘). The items variables subjectedto ANCOVA, the type I error represent a homogeneous construct (a = 0.76; was controlled for by applying the Bonferroni test-retestreliability =0.80; Basler et al., 1993). correction. Since hypotheseswere directed (treatment leads to improvement on dependent variables), a one-tailed significance level was chosen. Well-being. The well-being questionnaire Before conducting ANCOVAs, assumptions of normal distribution for each outcome measure (Herda, 1997)measuresgeneralwell-being during in each cell were tested. Tabachnik and Fidel1 the past 2 weeks. The seven items asking for experiencesof positive affect have to be rated (1989, p. 72) suggest that values for skewness on a six-point scale (e.g. ‘I felt comfortable’, and kurtosis be divided by their corresponding standard error, and the resulting z-distributed ‘I enjoyed life’). Psychometric quality has been reported to be good (internal consistency tl= quotients be tested against the null hypothesis of zero skewnessand zero kurtosis. Following their 0.87-0.92). recommendation to use conservative a levels and to account for the number of tests performed, Depression. The German version (Hautzinger, the a level was set at 0.001 (two-tailed test) and 1988) of the Center of Epidemiological Studies’ the Bonferroni correction was applied (a level divided by the total number of statistical tests). Depression Scale (Radloff, 1977)was used. The In addition, homogeneity of regression was depatient indicates on a four-point scalethe number of days over the last week he experienced each termined by evaluating independent variable of the 16 depressive and four non-depressive interaction (Tabachnick & Fidell, 1989; p. 336). The level of significancewas adjusted for the type symptoms (e.g. ‘During the last week, I felt I error. lonely’). The psychometric quality of the instruments To assesslong-term maintenance, in a second in this study was assessedby measuring internal step, pre-treatment scores were compared with consistency for all subjects at the first measure- 6-month follow-up scoresfor all treated subjects ment point, and test-retestreliability was assessed by using t-tests for dependent samples. Again, European

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outcome

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G, treatment group; CG, control r,, test-retest reliability (3 months). ‘Significant at Bonferroni-adjusted

Tl,

4.81 (0.61) 28 4.50 (1.14) 29

4.19 (0.53) 28 3.79 (0.96) 29

a-level

T2, follow-up;

of 0.05 * 2/12 =0.0083.

pretreatment;

15

n, number

of subjects;

18.36 (8.81) 22

16.45 (7.54) 22 deviation;

3.62 (1.15) 24

4.03 (0.76) 21

3.42 (1.48) 23

3.69 (1.06) 24

3.86 (0.68) 21

3.17 (1.47) 23

3.59 (1.04) 23

14

3.77 (1.25) 23

2.88 (0.51)

4.27 (0.90) 23

14

15

23

3.62 (1.66) 21

21.45 (7.36)

66.67 (17.13) 2.”

5.61 (2.08) 23

3.63 (0.97) 24

CG T2 Mean (SD) n

3.99 (1.04) 23

2.55 (0.50)

3.75 (1.60) 21

16.10 (7.47)

23

5.83 (1.64) 23

3.75 (0.74) 24

70.47 (17.45)

SD, standard

27

5.25 (1.27) 30

3.99 (1.22) 30

12.54 (10.43)

5.18 (1.11) 29

3.98 (1.20) 29

27

5.13 (0.65) 30

4.09 (1.05) 30

15.66 (10.72)

3.46 (0.32) 33

33 -

2.45 (0.58) 33

27.85 (15.80)

30

2.21 (1.68) 29

33

18.92 (12.11)

83.11 (17.28)

3.37 (2.39) 29

30

(20.03)

3.10 (2.08) 29

4.52 (2.40) 29 74.48

2.47 (1.11) 30

instruments

CG Tl Mean (SD) n

of the assessment

TG T2 Mean (SD) n

properties

3.27 (0.87) 30

TG Tl Mean (SD) n

and psychometric

one-sided

group;

Pain frequency (I-5) t-,=0.59 (n=24) Typical pain intensity (O-10) r,=O.58 (r/=23) Functional capacity (O-100) a=O.86 (n=53); r,=O.85 (r/=23) Strength and endurance (# repetitions) ~~0.76 (n=53); r,=O.82 (n=15) Disability (O-IO) a=o.95 (n=50); r,=O.84 (n=21) Video-supported observation (I-4) cr=O.87 (n=47); r,=O.75 (n= 14) Behavioural habits (l-6) a=O.77 (n=53); r,=O.77 (n=23) Posture-related self-efficacy (I-7) a=O.85 (n=52); r,=O.66 (n=23) Pain-related self-efficacy (I-7) a=0.86 (n=53); r,=O.58 (n=23) Attitudes towards posture and pain (I-6) a=O.55 (n=49); r,=O.64 (n=21) Well-being (l-6) a=0.87 (n=53); r,=O.74 (n=24) Depression (O-60) a=&90 (n=49); r,=O.61 (n=22)

TABLE

a, internal

consistency;

F(1;51)=10.42 p= 0.002” /=(1;49) = 12.26 p=O.OOl” F(1;50) = 27.89 pc0.001” F( 1;45) =2.07 p>o.o5 f=(1;47) = 16.35 ~0.001” /=(I;441 =34.36 pc0.001 a F( I;501 =20.50 F 0.001” /=(I;491 = 29.95 pc0.001” F(1;50) = 16.62 p<0.001” F(1;46)=11.13 p=O.O02” /=(1;50) = 14.01 pc0.001” F(1;46)=7.00 p=O.Oll

ANCOVA

MULTIDISCIPLINARY

the level of significance was adjusted according to Bonferroni. Results Short term

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outcome

Test of assumptions

Long-term

outcome

No differences between ‘drop-outs’ (measures only pre- and post-treatment) and ‘maintainers’ (measuresalso at follow-up) were found for any of the outcome measures. At the follow-up assessment,most of the improvements reported abovehad beenmaintained. t-testsrevealedimproved scorescompared to pretreatment scores on both pain frequency and typical pain intensity. These changes were accompanied by better daily functioning, and also, in contrast to the post treatment findings, by improved strength and endurance. Disability scores,on the other hand, remained unimproved. Observation of posture and behavioural habits confirmed the improvements reported before. Self-&cacy measuresshowed differential effects. While posture related self-efficacy was higher at follow-up, ratings of pain related self-efficacy were not improved. Patients’ attitudes towards posture and pain, on the other hand, were more favourable compared to pre-programme values. These changescorresponded with improvements in well-being, whereas depression scores remained unchanged as before.

According to the procedure outlined above, a critical z value of 3.29 was computed to accept significant skewnessand kurtosis. The a level for the tests on homogeneity was set at 0.05/12= 0.0042.On this basis, only the distribution of the post-treatment depressionscoresof the treatment group was not considered to be normal. On the other hand, Stevens (1992) only recommends dismission of the assumption of a normal distribution for a specific set of variables in cases of more than one violation. Consequently, as computations ascertain the assumption of homogeneity of regression and no further violations occur, criteria for the application of covai!iance analysesseem to be fulfilled. On the basis of one-tailed tests of significance and 12 significance tests, an a level of 0.05 * 2112=0.0083 was chosen. As Table 2 demonstrates, ANCOVAs reveal significant treatment effects for most of the outDISCUSSION come measures. Pain frequency, typical pain intensity and disability causedby pain were reduced Based on existing models of pain chronicity and as a consequenceof the treatment. There was effective treatment strategies for patients with an improvement in daily functioning, although chronic low back pain, a multidisciplinary restrength and endurance were not affected ac- habilitation programme for an outpatient group setting has been developed. Participation in the cording to the authors’ strict statistical criteria. Behavioural observationsclarify that posture and rehabilitation programme led to statistically and performance of daily activities improved. This clinically significant short-term improvements in effect corresponded with improvements in self- almost all dependent variables compared to a reported behavioural habits, self-efficacyrelated waiting-list control group. Most of these imto posture and pain management, and attitudes provements were maintained at 6-months followrelated to posture and pain. Of the affective up. Major treatment goals could be achieved: patients reported a significant decreasein pain criteria for successful pain management, only well-being as a measure of positive affect was frequency and typical pain intensity, which was significantly augmented by treatment, while still evident at follow-up. scores on the depression scale did not reach Improvements in pain experience were acBonferroni-adjusted significance. Table 2 gives companied by somewhat inconsistent results with the psychometric properties of the assessment respect to physical functioning. The extent of instruments and the cell-wise scoreson the outperceived functional capacity and perceived discome variables, apart from summarizing the res- ability can be seenas closely related to the physults of the ANCOVAs. ical functioning that is addressedby the exercise European

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programme and the training of activities of daily living. Functional capacity and perceived disability were improved after the programme had terminated. At follow-up, however, the scoresfor both variables were not significantly higher than before treatment. This may be explained by the fact that the subjects in this study reported comparatively high functional capacity (75%) and low disability scores(mean of 3.4 on a scalefrom 0 to 10) at the beginning of the treatment, in spite of an averagepain chronicity of more than 9 years. Although mean scores moved in the expecteddirection, further improvements at follow-up may not have been found becauseof a floor effect. The significant improvement of the participants post-treatment may primarily be due -to an amelioration of the respectivescoresin the waiting-list group. In contrast to these findings, a significant improvement of the muscle strength and endurance score could only be found as a long-term effect. The direct effects of physical training were assessedby an overall score for muscular strength and endurance, operationalized as a maximum number of repetitions of four different exercises (including knee-bending, extension and bending of the trunk). A possible explanation for not finding any short-term effects could be that the intervention of 6 weeks duration was not long enough to result in a significant improvement of muscle strength and endurance, and that the intended effect was measurable only after an extended training period. This assumption is in contrast with other studies that could document a significant increasein muscle strength after only 4 weeks,measuredisometrically by dynamometer methods (Estlander et al., 1991; Mellin et al., 1993).Two alternative explanations may be relevant to the present findings: (1) it seemslikely that the score used in the present study mixes aspectsof strength and endurance,and therefore, may not be specific and valid enough; or (2) the 47% pre- post-treatment improvement of the treatment group score is not significantly higher relative to the surprisingly large improvement in the waiting-control group (33%). At follow-up, the score reaches statistical significance because the improvement is not seenrelative to changes in a control group. As a consequenceof this European Journal

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inconsistency, measures applied for the assessment of changes in physiological variables in future studies should be more specific, more objective and of higher validity. Using a sub-group of this sample, Tiilke (1996, unpubl. data) found that more specific measures document a significant increasein muscle strength and flexibility. The back-school elements in the treatment programme were designedto addressspecifically the performance of activities of daily living and behavioural habits. After the intervention, treated subjects reported a significantly*better adherenceto back-relevant behaviours than the control group. Additionally, the standardizedbehavioural observation method confirmed that participants, in contrast to control subjects, had learned how to perform activities of daily living adequately. With regard to the affective variables, no significant treatment effects-neither at post-treatment nor at follow-up-could be found for depression,while well-being was significantly increasedat both assessments.This might be due to the fact that the programme explicitly addressed positive behaviours and the intended shift of the focus of attention from activities in which patients were restricted to those which they were able to enjoy. This may have led to an increase in perceived well-being. Coping with feelings of depression,however, was not an explicit issue of the treatment programme. Nonetheless, changes in mean depressionscorespointed in the expected direction and stayed below the cut-off point for clinical depression (i.e. below 18/60 points). Participation in the programme produced a significant change in the relevant cognitive variables. Participants changed their attitudes towards back-relevant behaviour in a positive direction. In addition, their senseof self-efficacy with respect to a pain-free performance of activities of daily living and the performance of back-relevantposture habits increased.Theseimprovements were maintained at follow-up, with the exception of pain-related self-efficacy.In several theories that try to explain the process of behaviour change (e.g. the Theory of Planned Behaviour, Ajzen, 1991), these two components-attitudes and perceived behavioural control or self-efficacy-are considered crucial

variables in explaining behavioural intentions and behaviour. According to theseconcepts,positive attitudes toward back-relevant behaviour, a substantial feeling of control over it, combined with the documented ability to perform the respective behaviour, should result in a long-term stability of the changesin behavioural habits that have been reported by the programme participants. Additional evidencefor this assumption can be seenin the fact that, at follow-up, more than three-quarters of the subjects reported paying attention to the way they performed various activities of daily living ‘most of the time’ or ‘always’. More than half of the subjectsindicated that they had maintained or even increasedtheir level of activity or physical exercisesince the end of the-treatment. About two-thirds reported that their complaints due to back pain had considerably decreased during the 6-months after the programme had ended. The fact that only one subject dropped out of treatment suggests that the programme met the specific needsof the participants. From a methodological perspective, the present authors tried to follow the suggestionsof Flor et al. (1992) by: (1) providing a comprehensive patient sample description; (2) using an adequate control group; (3) using (mostly) well-established outcome measures;and (4) providing all relevant data, including standard deviations and sample sizes. The overall results underline the effectiveness of the programme, which is impressive, especially if one considers the rigidly controlled design and the conservative statistical procedures used. The major limitation of this study clearly lies in the comparatively small sample size. A replication of the study with a larger sample size is needed to confirm the benefits that participation in the programme will bring for pain patients. Additional variables such as objective data on return to work or sicknessdays should be included in future studies, as well as more specific measures for the changes in a patient’s physical performance. Considering the intensity of the treatment approach (18 group sessions plus 18 individualized trainig sessions),more information about cost-effectivenessand a comparison with the effects of a similar programme in an inpatient setting would be interesting. European

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Further studies are needed, not only to rep- Basler H-D. Group treatment for pain and discomfort. Special issue: Psycllosocial aspects of rheumatic diseases. licate the results of this evaluation, but also to Patient Educ Coun s 1993; 20: 1677175. find out more about the differential effectsof the BaslerH-D. Chronilizierungsprozessevon Rtickenschmerzen. Ther Umsch 1994; 61: 395402. severaltreatment components. Although most of Basler H-D. Patient education with reference to the process the changesweremaintained at follow-up, further of behavioral change. Patient Educ Courts 1995; 26: 93-98. development of the intervention should aim at a Basler H-D. Incornoration of coanitive-behavioral treatgreater improvement in relevant variables (espement into the medical care of chronic low back patients: a controlled randomized study in German pain treatment cially physical functional capacity, perceived discenters. Patient Educ Courts 1997; 31: 113-124. ability and depressionscores),and at a long-term Basler H-D, Beisenherz-Hahn B, Frank A, Griss P, Herda maintenance of the newly acquired behaviour. C, Keller S. Preventing pain attacks by low back school training. Der Schmerz 1993; 7: 268-279. One way to achieve this could be that the psyBasten M, Basler H-D. Verhaltensbeobachtung zur Erchological knowledge regarding the ..processof folgsmessung einer Rtickenschule zur Prtivention chronbehavioural change is even more intensively inischer Schmerzen. Der Schmerz 1993; 7: 113-121. tecrrated.Prochaska et al. (1992) Biering-Sorensen F, Bendix T, Jorgensen K, Manniche C, \ , introduced a Nielsen H. Physical activity, fitness and back pain. In: model of change assigning subjects to distinct Bouchard C et al., editors. Physical Activity, Fitness and stages called precontemplation, contemplation, Health: Proceedings and Consensus Statement. Champreparation for action, action and maintenance. paign, IL: Human Kinetics Publisher, 1994: 737-748. He was able to demonstrate that the stage of ‘Bradley LA. Cognitive-behavioral therapy for chronic pain. In: Gatchel RJ, Turk DC, editors. Psychological Apchange a person is assignedto has an impact on proaches to Pain Management-A Practitioners Handthe outcome of a treatment. A beneficial outcome book. New York: The Guilford Press, 1996: 131-147. is more likely to occur in subjects who are pre- Brtigger A. Die Erkrankungen des Bewegungsapparates und Seines Nervensystems. Zurich: Verlag Brtigger, 1980. pared for taking action, as compared with subChaffin DB, Ashton-Miller JA. Biomechanical aspects of jects at the precontemplation or contemplation low-back pain in the older worker. Exp Aging Res 1991; levels. Assessingthe stage of readinessand then 17: 177-187. Cohen JE, Goel V, Frank JW, Bombardier C, Peloso P, introducing specific educational or behavioural Guillemin F. Group education interventions for people interventions designedto move patients along in with low back pain. Spine 1994; 19: 12141222. terms of willingness to change might enhance Croft PR, Papageorgiu AC, Ferry S, Thomas E, Jayson compliance (Basler, 1995)and long-term stability MIV, Silman AJ. Psychologic distressand low back pain. Spine 1996; 20: 2731-2737. of the respectivebehaviours. DiFabio RP Efficacy of comprehensive rehabilitation programs and back school for patients with low back pain: A meta-analysis. Phys There1995; 75: 865-878. Dillmann U, Nilges P, Saile H, Gerbershagen HU. Behinderungseinschatzung bei chronischen Schmerz-

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