Spine
Issue: Volume 22(17), 1 September 1997, pp 2016-2024
Copyright: (C) Lippincott-Raven Publishers.
Publication Type: [Functional Restoration]
ISSN: 0362-2436
Accession: 00007632-199709010-00016
Keywords: compensation, disability, litigation, low back pain, rehabilitation
[Functional Restoration]
The Effect of Compensation Involvement on the Reporting of Pain and Disability
by Patients Referred for Rehabilitation of Chronic Low Back Pain
Rainville, James MD*+; Sobel, Jerry B. MD*; Hartigan, Carol MD*+; Wright,
Alexander MD*++
Author Information
From *the New England Spine Care Center, Chestnut Hill, Massachusetts, and the
Departments of +Rehabilitation Medicine and ++Orthopedic Surgery, Tufts
University Medical School, Boston, Massachusetts.
Acknowledgment date: May 13, 1996.
First revision date: December 2, 1996.
Acceptance date: March 13, 1997.
Device status category: 1.
Address reprint requests to: James Rainville, MD; New England Spine Care
Center; 830 Boylston Street; Chestnut Hill, MA 02167.
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Outline
Abstract
Materials and Methods
Results
Comparisons of Presenting Characteristics of All Study Subjects
Treatment Recommendations, Compliance, and Compensation Involvement
Comparisons of Patients Completing Spine Rehabilitation
Discussion
References
Abstract
Study Design. In this prospective, observational, cohort study of 192
individuals with chronic low back pain, the group of individuals was divided
based on compensation involvement, and their presentation pain and disability,
treatment recommendations, and compliance were compared. For 85 of these
individuals who completed a spine rehabilitation program, their pain and
disability at 3 and 12 months were compared.
Objectives. To test the theory that individuals with compensation involvement
presented with greater pain and disability and would report less change of pain
and disability after rehabilitation efforts.
Background.Previous studies have produced conflicting results concerning this
issue.
Methods.Individuals were recruited as consecutive patients referred for
consultation at a spine rehabilitation center. Pain, depression, and disability
were assessed using self-report questionnaires at evaluation and at 3 and 12
months. Rehabilitation services consisted of aggressive, quota-based exercises
aimed at correcting impairments in flexibility, strength, endurance, and
lifting capacity, identified through quantification of back function. Multifactoral
analysis of variance models were used to control for baseline differences
between compensation and noncompensation patients during analysis of target
variables.
Results.The compensation group included 96 patients; these patients reported
more pain, depression, and disability than the 96 patients without compensation
involvement. These differences persisted when baseline differences were
controlled for with multifactoral analysis of variance models. Treatment
recommendations and compliance were not affected by compensation. For patients
completing the spine rehabilitation program, length of treatment, flexibility,
strength, lifting ability, and lower extremity work performance before and
after treatment and patient satisfaction ratings were similar for the
compensation and non-compensation groups. At 3 and 12 months, improvements in
depression and disability were noted for both groups, but were statistically
and clinically less substantial for the compensation group. At the 12 month
follow-up visit, pain scores improved for the noncompensation group, but not
for the compensation group.
Conclusions.In chronic low back pain, compensation involvement may have an
adverse effect on self-reported pain, depression, and disability before and
after rehabilitation interventions.
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Most experienced clinicians report a degree of pessimism when encountering
patients with chronic low back pain seeking or receiving compensation because
of their symptoms. Compared with noncompensation patients with similar
pathology, these patients seem to respond less well to interventions.
Previous medical research has supported the notion that compensation involvement
adversely influences the report of pain and disability, as well as outcomes
from treatments.4,5,16,19,21,23-26,43,44 Other studies have suggested that
those involved with compensation do not report increased pain or disability and
respond appropriately to treatments.1,7,12,15,31,32,40,42 The recruitment sites
of these studies have varied and include inpatient services, anesthesia and
multidisciplinary pain clinics, outpatient physician practices, and rehabilitation
services.1,4,5,7,16,19,21,23,25,27,31,40,42,43 Useful conclusions about this
subject remain unclear.
Analysis of the demographics of patients referred to the authors' spine
rehabilitation center revealed that nearly equal numbers of compensation and
noncompensation patients presented for evaluation and treatment of chronic low
back pain symptoms. The authors' had observed significant improvement in
measures of flexibility and strength and self-reported disability in a prior
setting in which they were exclusively treating patients receiving compensation
and using a functional restoration approach.35,36 Improvements also were noted
in patients' pain attitudes and beliefs, but despite all of these areas of
positive outcomes, reports of pain did not show any consistent improvement.36
One had to wonder if pain symptoms had actually lessened, but that reinforcements
for reporting pain within compensation systems had made patients reluctant to
report any improvements. In the current setting, compensation and noncompensation
patients are mixed in a spine rehabilitation program. Therefore, this was an
ideal site for observing potential differences between patients' presenting
characteristics and treatment outcomes based on compensation status.
This prospective, observational study was conducted to explore whether patients
presenting for evaluation and treatment of chronic low back pain differ, based
on compensation status, in their report of pain and disability. The authors
also were interested in whether compensation involvement affected treatment
recommendations, compliance, and responsiveness to rehabilitation efforts at 3
and 12 month follow-up visits. The authors theorized that compensation
involvement had a negative influence on the above areas.
Materials and Methods
Subjects. One hundred ninety-two consecutive patients with primary symptoms of
chronic (duration > 4 months) low back pain and/or sciatica evaluated by a
physicians at this center between October 1, 1993 and February 28, 1994 were
entered into a prospective data base if they: 1) were between the age of 18 and
70 years, 2) had no surgically correctable lesion as the cause of low back pain
or were not interested in pursuing surgical options, 3) were at least 3 months
postdiscectomy or 6 months postfusion, 4) possessed reading and writing
comprehension of the English language, and 5) had no concurrent medical illness
(cardiopulmonary, central nervous system, etc.) that produced significant
disability. Eighty-seven percent of patients were referred by physicians or
medical case managers, and the remaining 13 percent were self-referred.
Patients who were receiving or seeking financial compensation because of their
back pain were defined as having compensation involvement. This included
patients receiving Workers' Compensation, Social Security Disability, or
private disability policy benefits, or patients who were the plaintiff in an
unsettled personal injury suit. Ninety-six of the 192 study subjects were
involved with one or more of these areas of compensation, and 96 were not. The
types of compensation involvement are summarized in Table 1.
Of the 192 patients, 38 were evaluated only and did not receive any further
treatment. Three required advice only, seven were not interested in participating
in any recommended treatment secondary to travel distance, 21 were not
interested in pursuing recommended treatment options, and seven were denied
insurance authorization for further treatment. Twenty-three of the patients who
were evaluated but received no treatment had compensation involvement, and 15
did not.
The 154 remaining patients were referred to physical therapy for treatment of
their chronic back pain syndromes. Thirty-seven of the 154 patients had minimal
disability and were referred only for the development of independent back
exercise programs. Six of these patients had compensation involvement. The
remaining 117 patients had moderate to severe disability and were referred to a
spine rehabilitation program. Of these, 67 had compensation involvement. For
those referred to the spine rehabilitation program, 32 (27%) dropped out of the
treatment program; 20 of these patients (30%) had compensation involvement.
Reasons for discontinuing treatment included medical illnesses for six
patients, conflicts with work schedules for two patients, and lack of interest
in the treatment approach for 24 patients.
Eight-five patients completed the spine rehabilitation program, 47 of whom had
compensation involvement. These patients who completed the treatment program
will be the focus of the treatment outcome portion of this report.
Paper and Pencil Measures. At the initial evaluation, all patients completed a
questionnaire that inquired about demographic variables, symptoms, diagnostic
tests, prior treatments, compensation involvement, and work status. Self-reported
disability was measured with an Oswestry Disability Questionnaire (OSWESTRY)
with potential scores ranging from 0 (no disability) to 100 (severe disability).9
The intensity of pain was measured by 10-cm visual analog scales anchored with
0 (no pain) and 10 (worst possible pain) for back (BACK-VAS) and leg (LEG-VAS)
pain symptoms.14 Depression symptoms were measured by the Beck Depression
Inventory (BDI) with a range of scores from 0 (no depression) to 63 (severe
depression).2
Patient satisfaction was assessed with a 10-item questionnaire with potential
responses of 1 (excellent), 2 (very good), 3 (good), 4 (fair), and 5 (poor).
Questions assessed scheduling, business services, physician services, therapist
services, team-work, communication, education, home exercise instruction,
quality of care, and effectiveness of care. Responses to the 10 questions were
totaled with a range of scores from 10 to 50.
Follow-up Questionnaires.Three months after the initial evaluation, a research
assistant mailed a follow-up packet to all patients. Packets included an
OSWESTRY, BDI, BACK-VAS, LEG-VAS, and a Patient Satisfaction Questionnaire.
Twelve months after the initial evaluation, another follow-up packet was mailed
to all patients in the study. Packets included a stamped return envelope. If no
response was received in 3 weeks, a second packet was mailed. After 3 more
weeks, phone calls (maximum of three) were placed to all nonresponding patients.
If contacted, patients were given the options to complete the questionnaires on
the phone. When not at home, instructions were left with household members or
on answering machines to contact the research assistant or to complete the
mailed questionnaires.
Quantification of Physical Function. Trunk flexibility, straight leg raising,
trunk strength, lifting ability, and lower extremity work endurance were
quantified before and at the completion of spine rehabilitation.
Maximum trunk flexion and extension in the standing posture was measured with a
single inclinometer (AngleLevel, Dejon Tool Co, Covington, OH) placed over the
T12 spinousprocess.37 Maximum straight leg raising (SLR) was measured by
placing the inclinometer over the bony surface just below the tibialtuberosity
and raising the leg until significant back or leg pain occurred or until the
pelvis was observed to rotate.22,28
Trunk extension strength was quantified using Cybex back extension exercise
equipment (Lumex Corp., Ronkonkoma, NY). The testing procedure used a four-repetition
to maximum-weight-successfully-lifted protocol that is described in detail
elsewhere.41
Lifting ability was evaluated using the progressive isoinetrial lifting
evaluation (PILE) described by Mayer et al.30 The maximum weight lifted for
four repetitions from floor to waist was recorded as lumbar PILE, and that
lifted from waist to shoulder was recorded as cervical PILE.
To correct for anthropomorphic differences between patients, maximum back
strength and PILE weights were converted into percent ideal body weight before
data analysis. Ideal body weight was calculated for patients by measuring
height and actual weight and estimating body type and comparing these
measurements with those on standardized, sex-specific charts.33
Lower extremity work performance was quantified using a 9-minute protocol on an
isokinetic exercise bicycle (Cybex Fitron, Lumex Corp., Ronkonkoma, NY) during
which kilogram-meters (kg-m) per minute of work were recorded.41
Treatment. The spine rehabilitation program uses exercise to eliminate
impairments in flexibility, strength, endurance, and lifting capacity. The
occurrence of pain with exercises was expected, and the patients were
encouraged to work through pain symptoms to complete the established exercise
quota. Exercise quotas were increased throughout treatment. Treatments occurred
in groups consisting of a maximum of eight patients and were led by a physical
therapist and an exercise physiologist. Behavioral techniques were used to
promote wellness behaviors (exercise) and to extinguish pain behaviors
(limping, moaning, declining to perform exercises, etc.). Hands-on treatments
and applied modalities were not offered. Nonsteroidal anti-inflammatory and
antidepressant medications were prescribed at the discretion of the evaluating
physician, but narcotic analgesics were not prescribed, and their use was
discouraged. Referrals for psychological counseling occasionally were
requested.
The first week of treatment included a comprehensive physical therapy
evaluation, quantification of physical function, instruction in a home
stretching program, and orientation to the treatment facility.
Patients then were enrolled in a Level 1 treatment group that consisted of 2
hours of physical therapy three times per week. Sessions included 1 hour of
stretching and 1 hour of exercise on strengthening and endurance equipment.
Strengthening equipment included Cybex Eagle Strength System (Lumbex Corp.,
Ronkonkoma, NY) back extension, rotary torso, multihip, and lat pull-down
machines, Roman chair (back hyperextension), PILE lifting station, dumb bells,
andtheraband. Endurance equipment included isokinetic bicycles (CybexFitron,
Lumbex Corp., Ronkonkoma, NY) and upper body ergometer (Cybex UBE, Lumbex
Corp., Ronkonkoma, NY). Initial strength, lifting, and endurance exercise
levels were based on evaluation test results. Patients usually attended five or
six Level I sessions.
Patients then entered Level II, where group sessions were increased to 2 hours
and 45 minutes and occurred three times per week. These sessions included 45
minutes of stretching, 1 hour of strengthening, and 1 hour of aerobic training
(including low-impact step aerobic exercise). Requantification of physical
function was performed biweekly and at the completion of treatment. Compliance,
behavioral problems, and treatment goals were discussed at biweekly team
conferences between therapists and physicians. In general, 5 weeks of Level II
was projected for patients, with a total treatment time averaging 8 weeks.
At discharge, all patients in the study received individualized, written
recommendations for exercise routines that were to be performed at home and/or
a fitness facility.
Statistical Methods. Statistical analyses were performed using SPSS statistical
software for personal computers (SPSS, Chicago, IL). Summary statistics were
computed. Comparisons between those with and without compensation involvement
were done using chi-square tests for nominal variables and independent-sample t
tests for ordinal, interval, and ratio values.
Multivariate analysis of variance (MANOVA) techniques were used to determine
whether compensation involvement maintained its effect on self-reported pain
and disability when other differing characteristics were controlled. The first
step was to use multiple regression analyses, correlations, and two-way ANOVA
equations to identify cofactors and variables that had significant influence on
BACK-VAS, LEG-VAS, and OSWESTRY. These cofactors and variables then were entered
into MANOVA equations, which included compensation involvement as a cofactor.
Chi-square anddiscriminant analyses were used to explore the relationships of
compensation involvement with treatment recommendations and compliance.
Paired-sample t tests were used to compare physical function results at the
beginning and at the end of spine rehabilitation and questionnaire scores at
evaluation with scores at 3 and 12 month follow-up visits.
Results
Comparisons of Presenting Characteristics of All Study Subjects
For the entire cohort of 192 patients, substantial differences were noted in
many demographic, subjective, and objective characteristics when patients were
compared based on compensation involvement (Table 2). On average, those with
compensation involvement were less educated, were more likely to work jobs with
medium or heavy labor, were more likely to relate a compensatable event to the
onset of symptoms, had more reports of leg pain, had more neurologic signs and
symptoms, were less flexible, and were more likely to report pain with trunk
movements and straight leg raising. They also reported higher levels of pain,
depression, and disability. These findings suggest that patients with
compensation involvement had more serious chronic back pain syndromes.
Further analyses identified depression (BDI), education, and age as variables
that might influence the differences in initial pain scores (BACK-VAS and
LEG-VAS) between patients with and without compensation involvement. These
variables were entered into MANOVA equations with compensation involvement as a
factor and BACK-VAS, then LEG-VAS as the dependent variables. The results
indicated that compensation involvement maintained a strong influence on
BACK-VAS scores (F = 12.67, df = 1, P PP
Treatment Recommendations, Compliance, and Compensation Involvement
Chi-square analysis revealed that compensation involvement was not associated
with membership in the evaluation only group. Discriminantanalysis revealed
that referral to an individual physical therapy program was determined mainly
by the characteristics of low OSWESTRY and BDI scores, mild impairments in trunk
flexibility, and lack of work disability (Wilks Lambda = 0.728, P
Chi-square analysis revealed that treatment compliance for the spine rehabilitation
program did not differ based on compensation involvement. The drop-out group
demonstrated higher mean scores for OSWESTRY (57 vs. 42, t value = 4.6, P vs.
5.9, t value = 2.36, P = 0.02), and age (45 vs. 39 years, t value = 2.22, P =
0.03). The drop-out group contained a greater percentage of patients who had
failed pain programs (29% vs. 10%, chi-square = 3.9, df = 1, P = 0.05) and who