SPINE Volume 40, Number 14, pp 1140-1147 ©2015, Wolters Kluwer Health, Inc. All rights reserved.
LITERATURE REVIEW
The Influence of No Fault Compensation on Functional Outcomes After Lumbar Spine Fusion Alexander Sheriff Montgomery, Dipl Orth Eng, MRCS, FRCS (Tr and Orth),* John Edward Cunningham, BSc (Hons), MBBS, MClinEpi, FRACS, FAOrthA,† and Peter Alexander Robertson, MD, FRACS‡
Study Design. Prospective cohort study and systematic literature review. Objective. To compare the functional outcomes for lumbar spinal fusion in both compensation and noncompensation patients in an environment of universal no fault compensation and then to compare these outcomes with those in worker’s compensation and nonworkers compensation cohorts from other countries. Summary of Background Data. Compensation has an adverse effect on outcomes in spine fusion possibly based on adversarial environment, delayed resolution of claims and care, and increased compensation associated with prolonged disability. It is unclear whether a universal no fault compensation system would provide different outcomes for these patients. New Zealand’s Accident Compensation Corporation (ACC) provides universal no fault compensation for personal injury secondary to accident and offers an opportunity to compare results with differing provision of compensation. Methods. A total of 169 patients undergoing lumbar spinal fusion were assessed preoperatively, at 1 year, and at long-term follow-up out to 14 years, using functional outcome measures and healthrelated quality-of-life measures. Comparison was made between those covered and not covered by ACC for 3 distinct diagnostic categories. A systematic literature review comparing outcomes in Worker’s Compensation and non-Compensation cohorts was also performed. Results. The functional outcomes for both ACC and non-ACC cohorts were similar, with significant and comparable improvements
From the *St Bartholomews Hospital and The Royal London Hospital, London, England; †The Royal Melbourne Hospital and the Epworth Richmond, Melbourne, Australia; and ‡Department of Orthopaedic Surgery, Auckland City Hospital, Auckland, New Zealand. Acknowledgment date: June 4, 2014. Revision date: December 4, 2014. Acceptance date: February 23, 2015. The device(s)/drug(s) is/are FDA approved or approved by corresponding national agency for this indication. No funds were received in support of this work. Relevant financial activities outside the submitted work: consultancy, payment for lectures, patents, royalties. Address correspondence and reprint requests to Peter Alexander Robertson, MD, FRACS, The Orthopaedic Clinic, Mercy Specialist Centre, 100 Mountain Rd, Epsom 1023, Auckland, New Zealand; E-mail: [email protected] DOI: 10.1097/BRS.0000000000000966
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over the first year that were then sustained out to long-term followup for both cohorts. At long-term follow-up, the health-related quality-of-life measures were the same between the 2 cohorts. The literature review revealed a marked difference in outcomes between worker’s compensation and non–worker’s compensation cohorts with a near universal inferior outcome for the compensation group. Conclusion. The similarities in outcomes of patients undergoing lumbar spine fusion under New Zealand’s universal no fault compensation system, when compared with the dramatically inferior outcomes for these patients under other worker’s compensation systems, suggest that the system of compensation has a major influence on patient outcomes, and that change of compensation to a universal no fault system is beneficial for patients undergoing lumbar fusion surgery. Key words: workers’ compensation, scoring methods, spinal fusion, spondylolisthesis, employment, return to work, literature review, compensation, injuries, spinal stenosis, back pain. Level of Evidence: 2 Spine 2015;40:1140–1147
C
ompensation and litigation have adverse effects on outcomes in lumbar spinal disorders and lumbar surgery, including fusion operations.1 These adverse effects are also found in other orthopedic and nonorthopedic outcomes.2–8 The adverse factors associated with compensation include an adversarial environment; unpredictable outcomes for claimants, delayed claim resolution, exacerbated illness behavior promoting disability payments, psychosocial factors associated with the workplace environment, and evaluation and medical systems that differ from normal clinical care.9,10 Evaluating the possible factors disadvantaging compensation patients is difficult11 as compensation systems are legislated in social policy that reflects national and societal values. Cassidy et al12 observed the effects of a change in compensation for whiplash patients. Claim numbers, time to resolution, pain, function, and claim costs all improved when compensation payments for pain and suffering were removed. Conversion from a tort to a no fault system has also reduced claim incidence in Canada.13 These studies suggest that claimant behavior and outcomes alter with legislative change and, therefore, may differ under differing compensation systems.
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LITERATURE REVIEW
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
In 1974, New Zealand changed its previous tort-based accident liability and compensation system to a universal no fault system under the control of the state run Accident Compensation Commission (ACC). The ACC covers all accidents including workplace, home, sporting, and vehicular accidents. The ACC (later, the Accident Compensation Corporation) is legislated to promote safety, provide both acute and delayed treatment to accident victims, and provide compensation for wage and salary loss. The provision of this “universal compensation” occurred in exchange for removal of the right to sue for personal injury. The system is funded by both employee and employer levies, petrol taxes, and vehicle licensing fees. The employer contributions vary on the basis of injury risk. The ACC legislation has become enshrined in New Zealand society and widely accepted as a positive legislative advance (Table 1). Given that New Zealand’s ACC legislation removed several potential adverse factors that may influence outcomes for compensation patients, a study of outcomes comparing ACC and non-ACC patients, along with Workers Compensation (WC) and Non Workers Compensation (non-WC) patients from other nations, may shed further insight on the merits of a universal no fault compensation system.
The aim of this study was to compare outcomes in patients undergoing lumbar spinal fusion (LSF) dependent on whether or not they were compensated under the ACC system. We then compared functional outcomes in New Zealand’s ACC patients with both WC and non-WC patients outside New Zealand. The initial study is a prospective study of outcomes in a single surgeon practice over a decade. Comparison of ACC patient outcomes with WC outcomes was performed after a systematic literature review of both compensation and LSF.
MATERIALS AND METHODS Functional Outcomes for ACC Lumbar Spinal Fusion Patients For more than 10 years (1997–2006), 428 patients underwent elective LSF under the care of a single surgeon, forming the basis of this study. Functional outcomes scores were collected prospectively before surgery and at 12 months postoperatively. Scores were then collected again at the long-term follow-up (mean: 8 yr, range: 4–14 yr) after surgery. Additional health-related quality of life (HRQOL) measures were collected at the long-term follow-up point.
TABLE 1. Characteristics of New Zealand’s Accident Compensation Corporation (ACC) System Description
A no fault compensation system for personal injury by accident.
Goals
Injury prevention, treatment, rehabilitation, and earnings compensation.
Injury treatment
Acute and delayed medical and surgical care with rehabilitation on a contracted noncapped fee-for-service basis.
Medical accident insurance
ACC provides cover for treatment injury (medical error/malpractice) with treatment- and earnings-related compensation.
Income replacement
Wage and salary replacement at 80% preinjury level until rehabilitation to the workforce. Cases with injuries unable to be returned to work have continuing income replacement.
Claim management
Major claims have integrated client-centric case management by ACC with facilitation of assessment, access to care, and rehabilitation.
Administration
ACC is a state-based agency that is the sole provider of accident insurance. Income is via levies and taxation (see later). The system is fully funded to account for outstanding claims liability.
ACC Income by components
Employee levy—16%; employer levy—22%; general taxation—19%; motor vehicle levy—17%; interest—25%
Societal cost
Levies represent a societal cost of $NZ1000 per person per annum; employee levy is 1.48% of income; employer levy is 1.15% of liable wage/salary (varies dependent on industry risk rating); motor vehicle levy is $335 per vehicle per annum.
Societal benefits
Treatment—30%; income replacement—23%; long-term care—10%. Remaining income invested to fund outstanding future claims liability.
Administration and operating costs
10% of levy revenue.
Controls on medical surgical practice
ACC does not in general limit investigation or treatment. Protocols are rare but guidelines are developed for some conditions with professional body input.
Reimbursement rates for medical and Fee-for-service care with fees estimated at 75% of mean non-ACC rates. surgical care Adapted from 2013 Annual Report, Accident Compensation Corporation. http://www.acc.co.nz/PRD_EXT_CSMP/groups/external_communications/documents/reports_results/annual_report_2013.pdf. ACC indicates Accident Compensation Corporation.
Spine
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LITERATURE REVIEW A case was defined as an ACC case if the New Zealand Accident Compensation Corporation accepted the patient’s condition. To compare the functional outcomes of ACC patients with non-ACC patients, patients were selected with diagnoses where there were significant numbers of patients in the ACC and non-ACC cohorts. The 3 diagnoses were isthmic spondylolisthesis, discogenic disease causing low back pain, and foraminal stenosis requiring wide decompression and subsequent fusion. The functional outcome scores used were the Roland Morris Disability Questionnaire (RMDQ) and the low back outcome score (LBOS). The HRQOL measure was the SF-12v2.
Statistical Analysis Analysis of the short and long-term RMDQ difference was performed with the minimal clinically important difference (MCID) threshold set at both 4 and 8 points and reported as percentage of patients achieving the MCID threshold. Two levels of MCID for the RMDQ were selected, as the lower is the recognized MCID,14 yet a higher threshold may be more appropriate for major interventions demonstrating real change in function.15 The LBOS MCID at both time points was set at 7.5 points and reported in the same manner.16 The SF-12v2 surveys were scored using QualityMetric Health Outcomes Scoring Software 3.0 (QualityMetric Incorporated, Lincoln, RI), reporting physical component score and mental component score centiles against 1998 US normative data, and SF-6D R2 score. Statistical analysis of normal continuous variables, the RMDQ and LBOS scores, was by 2-sample paired t test and of binary outcomes; the MCID scores, by tests of proportions. The SF12v2 score domains and SF-6D R2 were compared using the Wilcoxon rank sum test. Missing data and their calculated variables were not considered. A value of P less than 0.05 was considered statistically significant, and analysis was performed using Stata v11, Statacorp LP, TX.
Systematic Literature Review—Functional Outcomes in Lumbar Spine Fusion Patients Covered by Worker’s Compensation
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
TABLE 2. Breakdown of Characteristics of Study
Groups
ACC
Non-ACC
Number
120
49
Male
55%
37%
Age
53 (24–81)
61 (31–82)
1
75
33
2
42
15
3
3
1
Foraminal stenosis
30
9
Isthmic spondylolisthesis
34
20
Painful spondylosis
56
20
Number of levels fused
Diagnosis
ACC indicates Accident Compensation Corporation.
(76: 56 ACC/20 non-ACC), and fusion after wide decompression for spinal stenosis (39: 30 ACC/9 non-ACC). Patient characteristics were matched apart from age where the non-ACC group was older (61 vs. 53 yr, P < 0.05) (Table 2). RMDQ scores (0–24, 24 = maximum disability) revealed severe disability preoperatively in both ACC (mean: 17.2, 16.4–18.0) and non-ACC (15.4, 14.2–16.7, P < 0.05) groups. There was dramatic reduction in disability at the 1-year postoperative mark in both groups (RMDQ mean ACC: 8.0, 6.8–9.2/non-ACC: 4.6, 2.8–6.5, P < 0.05). The improvements between preoperative and 1 year postoperative disability were significant in both groups (P < 0.05). At long-term follow-up, the disability improvement was maintained in both groups, and there was no difference between ACC and non-ACC patients (ACC: 5.9, 4.7–7.1/non-ACC: 3.8, 1.9–5.8, P > 0.05). There was no significant difference between the 1-year and long-term follow-up scores, indicating that the improvement was sustained (Figure 1).
To examine the published influence of compensation upon functional outcomes after lumbar spinal fusion, a systematic literature review was performed. MEDLINE, EMBASE, and the Cochrane Controlled Trials register were searched for “compensation” and “lumbar fusion.” Included studies required compensation patients undergoing LSF, recognized functional outcomes scores, and a minimum of 12 months of follow-up.
RESULTS Surgical Outcomes A total of 169 patients underwent an LSF for the indications described. Seventy-one percent of these were covered by ACC. The patient numbers were isthmic spondylolisthesis (54 patients: 34 ACC/20 non-ACC), discogenic low back pain 1142
Figure 1. Graph of RMDQ scores over time for ACC and non-ACC patients (mean ± 95% confidence interval). Range: 0 to 24, lower scores indicating better function RMDQ indicates Roland Morris Disability Questionnaire; ACC, Accident Compensation Corporation.
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LITERATURE REVIEW Examining the LBOS (0–75, 0 = maximum disability), the preoperative disability and changes with surgery revealed similar findings to the RMDQ. Before surgery, the LBOS indicated significant disability in both groups (ACC: 26.0, 23.8– 28.1/non-ACC: 31.9, 27.6–36.1, P < 0.05). Both groups improved significantly at 1 year (ACC: 43.9, 39.9–48.0/nonACC: 54.1, 48.4–59.9, P < 0.05). Although the non-ACC patients showed better LBOS at 1 year follow-up, they had demonstrated slightly less disability preoperatively. At longterm follow-up, the improvements were maintained and there was no difference between the ACC and non-ACC cohorts (ACC: 47.0, 43.5–50.4/non-ACC: 55.4, 49.3–61.6, P > 0.05) (Figure 2). The proportion of patients reaching the MCID of the RMDQ at the 1-year mark was the same between the ACC and non-ACC patients (MCID 4: ACC 84%, non-ACC 79%, P > 0.05; MCID 8: ACC 57%, non-ACC 72%, P > 0.05). This was similar at the long-term follow-up time point (MCID 4: ACC 91%, non-ACC 91%, P > 0.05; MCID 8: ACC 76%, non-ACC 71%, P > 0.05). Likewise, the proportion of ACC patients reaching the MCID of the LBOS was 74% at the 1-year mark, and 75% at the long-term point, without significant difference from the non-ACC patients (78%/73%, respectively) (Table 3). At long-term follow-up, the SF12v2 revealed no difference in either the physical component score or the mental component score domain scores for the ACC and non-ACC groups (physical component score: ACC 41.6 ± 11.5/non-ACC 44.0 ± 13.0, P > 0.05) (mental component score: ACC 50.3 ± 11.6/non-ACC 52.5 ± 9.9, P > 0.05) (Figure 3). The “whole of health” measure SF-6D R2 was not significantly different between the 2 groups (ACC 0.71 ± 0.17/non-ACC 0.76 ± 0.18, P > 0.05) (Figure 4).
Systematic Literature Review A total of 175 articles were located using the key words, of which only 25 articles discussed functional outcomes. None of these articles came from countries with no fault compensation systems. Of these, 16 articles used recognized functional outcome scores as a component of the assessment.17–32 Functional
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
TABLE 3. Percentage of ACC and non-ACC
Patients Achieving MCID at the 12-Month and Long-term follow-up Time Points, as Measured by the Improvement in RMDQ Scores by 4 and 8, and LBOS by 7.5 ACC MCID%
Non-ACC MCID%
12-mo RMDQ (4)
84
79
12-mo RMDQ (8)
57
72
12-mo LBOS
74
78
Long-term RMDQ (4)
91
91
Long-term RMDQ (8)
76
71
Long-term LBOS
75
73
ACC indicates Accident Compensation Corporation; MCID, minimal clinically important difference; RMDQ, Roland Morris Disability Questionnaire; LBOS, low back outcome score.
scores that had been used included the Oswestry Disability Index, LBOS, Stauffer-Coventry Score, Roland Morris Questionnaire, the SF-36/20/12, and visual analogue scale scores of pain. Ten of the articles presented studies from the United States. All but 2 of the articles from the United States demonstrated better outcomes in the non-WC cohorts. Of the other 2, 1 demonstrated equivalent outcomes in both groups, and the other reported good outcomes in a WC cohort.18,27 Both had major methodological problems. The former did not assess preoperative scores and so could not assess improvement and the latter used as its control group patients who were denied planned surgical treatment and then achieved follow-up of only one-third of the cohort. All articles from other countries demonstrated superior outcomes in the non-WC patient cohort, although Penta and Fraser23 demonstrated that the outcome superiority for the non-WC patients in Australia dissipated at long-term follow-up (Table 4). The negative effects of WC were seen in studies of posterolateral fusion,18,22,31 anterior lumbar interbody fusion,21,23 and posterior lumbar interbody fusion.28 The indications for surgery did not seem to alter the negative influence of WC. Fusion for isthmic spondylolisthesis did equally poorly as the majority of studies that focused on disc degenerative disease.20 When patients were compared in terms of those reaching an MCID, again there was a significant difference between the groups favoring the non-WC cohort.31
DISCUSSION Figure 2. Graph of LBOS scores over time for ACC and non-ACC patients (mean ± 95% confidence interval). Range: 0 to 75, higher scores indicating better function. LBOS indicates low back outcome score; ACC, Accident Compensation Corporation. Spine
Determination of the influence of compensation upon outcomes in spinal pathologies presents significant challenges. Compensation status is predetermined by the local accident liability legislation. Thus, compensation and relative variables cannot be randomized, and as with other sociopolitical factors, its role must be deduced by cohort observation. www.spinejournal.com
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LITERATURE REVIEW
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
Figure 3. PCS and MCS of SF-12v2, for ACC and non-ACC patients, measured at long-term followup. There was no significant difference between the scores of the ACC and non-ACC patients. PCS indicates physical component score; MCS, mental component score; ACC, Accident Compensation Corporation.
Studies in whiplash have shown that changes in compensation delivery significantly effect claimant behavior, outcomes, and costs.12 The literature strongly suggests that compensation has adverse effects upon LSF, yet the effect of differing types of compensation is unclear. New Zealand’s ACC is a universal no fault system of compensation that covers medical and rehabilitation costs, with provision of 80% replacement of income. It offers care and income stability in the context of a time of potential financial and psychosocial upheaval for the patient. In this respect, the ACC differs from other workers’ compensation and litigation environments where multiple adversarial factors have been identified. Adversarial systems that have unpredictable and delayed outcomes, legal representation, enhanced disability behavior to achieve financial gain, and models of care that differ from the norm are all likely to play a role in limiting access to care and rehabilitation, delaying return to normality. Although it is virtually impossible to study individual compensation characteristics that may disadvantage the injured patient, a study of outcomes of ACC and comparison with
Figure 4. SF-6D scores for ACC and non-ACC patients, measured at long-term follow-up. There was no significant difference between the scores of the ACC and non-ACC patients. ACC indicates Accident Compensation Corporation.
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WC and non-WC cohorts allows comparison of the effects of major legal and social differences between states and countries. LSF continues to be an operation with variable outcomes. The disability and psychosocial comorbidities in these patients are high. Given the outcome inconsistency, LSF represents an ideal procedure for study of the influence of compensation variations. This study has strongly suggested that the universal no fault compensation system in New Zealand does not disadvantage patients to the extent that compensation does elsewhere. Although ACC and non-ACC patients were highly disabled before surgery, both groups made comparable significant improvements with fusion surgery and at long-term follow-up were equivalent. The HRQOL measures were equal to the normal population. Attempting to compare New Zealand’s ACC patients with WC patients from other jurisdictions becomes more challenging. The literature is generally retrospective. Different outcome assessment tools have been used, some of which are widely accepted17,31 and some apparently custom designed.18 Variable diagnoses were included24,30,31 or the diagnosis before surgery was unclear.26 When comparisons were made with other cohorts, the control groups varied. WC patients are compared with non-WC patients undergoing spinal fusion.30 Other control groups include differing operative procedures,17 nonoperative patients,32 or patients whose surgical treatment was denied.18 Poor follow-up rates render some outcomes questionable.18 It is very clear in all studies that functional outcomes in WC patients undergoing LSF tend to be poor, and where comparison is made with non-WC cohorts, the implication is that the compensation is a major factor in the poorer performance of the WC group. The difficulties comparing outcomes across differing studies with differing outcome assessment tools would be reduced by the widespread use of MCIDs. Sporadic use has confirmed that this parameter also reveals WC to be an adverse effect.31 The use of MCIDs for our study of ACC and non-ACC outcomes demonstrates a much more robust improvement in
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Spine
SPINEI1404_LR 1145
2010
United States
United States
Nguyen et al32 2011
R
R
CC
P
R
P
R
RCT
R
R
P
R
P
P
R
P
Design
PLF
PLF/PLIF/ ALIF
PLF
PLF
PLIF
ALIF/PLIF
DS
DS
DS
DS/FS
DS
DS
DS
DS
PLF/PLIF / ALIF PLF
DS
DS
DS
DS
DS
DS
IS
DS
725
22
60
155
71
49
185
294
36
73
81
24
103
151
26
17
12
60
24
24
12
24
24
24
12
24
24
18
240
24
25
12
Number FollowDiagnosis of Patients up (mo)
PLF
ALIF/PLF
ALIF/PLF
PLF
ALIF
ALIF
PLF
PLF
Surgery
Disability
VAS/ODI
ODI/SF-36/VAS
Higher disability in WC than in control group
WC was a predictor for poor outcome
WC has significantly less improvement
WC worse in terms of relief of leg pain
WC results comparable with normative data scores
SF-36/patient satisfaction SF-36/VAS/ODI
WC had significantly worse outcomes
Poor results with a 24% reoperation rate
WC patients had inferior results
WC had significantly lower SF-36.
Non-WC associated with progression of symptoms
Good results in 91% of WC patients
WC strongly associated with poor operative results
WC worse at 2 years but dissipates over 10 yr
WC-significant prognostic factor in outcomes
WC had a profoundly negative influence on outcome
43% of WC patients had no relief of pain or made worse
Results
ODI/VAS
RMDQ/SCI/SF-20
VAS/ODI
SF-36
NOQ
VAS
Outcome rating
LBOS
LBOS
Functional results
Pain score
Outcomes
P indicates prospective; PLF, posterolateral fusion; DS, degenerative spondylolisthesis; WC, Workers Compensation; R, retrospective; IS, isthmic spondylolisthesis; ALIF, anterior lumbar interbody fusion; LBOS, low back outcome score; VAS, visual analogue scale; NOQ, NASS Outcome Questionnaire; SF-36, Short-Form 36 Multidimensional Health Survey; RCT, randomized controlled trial; PLIF, posterior lumbar interbody fusion; ODI, Oswestry Disability Index; RMDQ, Roland Morris Disability Questionnaire; SCI, Stauffer-Coventry-Index; SF-20, Short-Form 20 Multidimensional Health Survey; FS, foraminal stenosis; CC, case control.
South Korea
Kong et al30
Carreon et al 2010
2006
United States
31
Trief et al29
2003
United States
2003
Schiffman et al27
Madan and Boeree28
2001
United Kingdom
Sweden
Fritzell et al25
2001
2001
United States
Hodges et al17
2000
1997
1997
1997
United States
United States
Slosar et al24
Deberard et al26
United States
Hinkley and Jaremko18
Australia
Penta and Fraser23
United States
1994
United Kingdom
Greenough et al21
Vaccaro et al22
1988
United States
Hanley and Levy20
1984
Canada
Dzioba and Doxey et al19
Year
Country
Authors
Fusion
TABLE 4. Studies Identified Comparing Workers’ Compensation and Nonworkers’ Compensation Outcomes After Lumbar Spinal
LITERATURE REVIEW Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
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LITERATURE REVIEW spinal fusion across both cohorts, with MCIDs ranging from 57% to 91% dependent on the outcome score and follow-up. The strengths of this study include prospective collection of recognized functional outcome scores, both short and longterm follow-up out to 14 years, and a high rate of follow-up. The clear diagnostic categories with significant numbers of both ACC and non-ACC cases allow generalizability across both groups for diagnoses in the injury population. The study of a single surgeon practice is advantageous with consistent indications and techniques. The weaknesses of the study include the absence of HRQOL measures at the outset. This is in part because of the duration of the study with long-term follow-up. HRQOL measures were not in widespread use at the commencement of this study period. Because New Zealand’s ACC system includes all personal injuries as a result of accident, the study includes not only work injury but also vehicle, home, and sport injuries. It is possible that these latter injury activities may result in differing prognoses within a compensation system and lessen the perceived advantages of a universal no fault system specifically upon workplace injuries. There is no direct evidence of any difference in outcomes between work and nonworkplace injuries although accurate data are lacking. It is also clear that the vehicle injuries result in similar adverse effects on outcome in the compensated patient. The universality of the ACC system has lessened the focus on the location of injury, whereas these relevant liability details are likely to be carefully examined in an adversarial system. The benefits of the universal no fault compensation system have been demonstrated in other areas of injury treatment and rehabilitation. Economic status and return to work are better for ACC patients than for non-ACC patients with spinal cord injury33 and when major trauma patients are compared with disabling medical problems.34 ACC also seems to minimize whiplash as a long-term clinical problem.35 New Zealand’s ACC system has been subject to change and modification since its introduction 40 years ago, and these important changes must be acknowledged. Modest schedule-based payments for pain and physical impairment were an early feature of the scheme but ceased prior to this study. Acceptance of the definition of injury (the diagnosis of structural abnormality) and of accident has come under greater scrutiny. This has occurred subsequent to the study period. It is also accepted that the political leanings of the government of the day influence the ease or otherwise of obtaining coverage and benefit payment. Despite these variations in legislative and political flavor, the application of a universal no fault system providing care and economic compensation is unchanged. This study has not addressed any economic benefits and has not focused upon return to work. Although it is reasonable to conclude that improved function equates to gainful employment, the confounding variables of economic activity and opportunity may render return to work data less reliable than functional outcome measures when determining the real gains or otherwise for compensation and noncompensation patients. 1146
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
In summary, the universal no fault compensation system that exists for accident and injury victims in New Zealand seems to offer considerable advantage for patients whose condition requires treatment with LSF. This advantage is in terms of improved functional outcomes. The ACC patients achieve equivalent improvements to the non-ACC patients and improvements equivalent to the non-WC patients in the published literature. They also achieve function that is considerably better than that achieved in WC patients in adversarial compensation jurisdictions.
➢ Key Points In a universal no fault compensation system, patients undergoing lumbar spine fusion improve functionally in both the short and long term and are equivalent to the noncompensated patients. Conversely, literature review demonstrates that worker’s compensation patients in adversarial systems achieve significantly worse outcomes when compared with nonworker’s compensation patients. Compensation systems have a profound effect on the functional outcomes for lumbar spine fusion patients, and there are major advantages with a universal no fault system.
References
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LITERATURE REVIEW 12. Cassidy JD, Carroll LJ, Côté P, et al. Effect of eliminating compensation for pain and suffering on the outcome of insurance claims for whiplash injury. N Engl J Med 2000;342:1179–86. 13. Lemstra M, Olszynski WP. The influence of motor vehicle legislation on injury claim incidence. Can J Public Heal 2004;96:65–8. 14. Ostelo RWJG, de Vet HCW. Clinically important outcomes in low back pain. Best Pract Res Clin Rheumatol 2005;19:593–607. doi: 10.1016/j.berh.2005.03.003. 15. Patrick DL, Deyo RA, Atlas SJ, et al. Assessing health-related quality of life in patients with sciatica. Spine (Phila Pa 1976) 1995;20:1899–908; discussion 1909. 16. Khatri M, Murray M, Greenough CG. Minimum clinically important difference in low back outcome score in individuals with low back pain. J Bone Joint Surg Br Vol 2004;86-B(supp II):115. 17. Hodges SD, Humphreys SC, Eck JC, et al. Predicting factors of successful recovery from lumbar spine surgery among workers’ compensation patients. J Am Osteopath Assoc 2001;101:78–83. 18. Hinkley BS, Jaremko ME. Effects of 360-degree lumbar fusion in a workers’ compensation population. Spine (Phila Pa 1976) 1997;22:312–23. 19. Dzioba RB, Doxey NC. A prospective investigation into the orthopaedic and psychologic predictors of outcome of first lumbar surgery following industrial injury. Spine (Phila Pa 1976) 1984;9:614–23. 20. Hanley EN, Levy JA. Surgical treatment of isthmic lumbosacral spondylolisthesis. Analysis of variables influencing results. Spine (Phila Pa 1976) 1988;14:48–50. 21. Greenough CG, Taylor LJ, Fraser RD. Anterior lumbar fusion. A comparison of noncompensation patients with compensation patients. Clin Orthop Relat Res 1994;300:30–37. 22. Vaccaro AR, Ring D, Scuderi G, et al. Predictors of outcome in patients with chronic back pain and low-grade spondylolisthesis. Spine (Phila Pa 1976) 1997;22:2030–5. 23. Penta M, Fraser RD. Anterior lumbar interbody fusion. A minimum 10-year follow-up. Spine (Phila Pa 1976) 1997;22:2429–34. 24. Slosar PJ, Reynolds JB, Schofferman J, et al. Patient satisfaction after circumferential lumbar fusion. Spine (Phila Pa 1976) 2000;25:722–6.
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Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
25. Fritzell P, Hägg O, Wessberg P, et al. 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine (Phila Pa 1976) 2001;26:2521–4. 26. DeBerard MS, Masters KS, Colledge AL, et al. Outcomes of posterolateral lumbar fusion in Utah patients receiving workers’ compensation: a retrospective cohort study. Spine (Phila Pa 1976) 2001;26:738–47. 27. Schiffman M, Brau SA, Henderson R, et al. Bilateral implantation of low-profile interbody fusion cages: subsidence, lordosis, and fusion analysis. Spine J 2002;3:377–87. 28. Madan SS, Boeree NR. Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion. Eur Spine J 2003;12:567–75. 29. Trief PM, Ploutz-Snyder R, Fredrickson BE. Emotional health predicts pain and function after fusion: a prospective multicenter study. Spine (Phila Pa 1976) 2006;31:823–30. 30. Kong C-B, Jeon D-W, Chang B-S, et al. Outcome of spinal fusion for lumbar degenerative disease: a cross-sectional study in Korea. Spine (Phila Pa 1976) 2010;35:1489–94. 31. Carreon LY, Glassman SD, Kantamneni NR, et al. Clinical outcomes after posterolateral lumbar fusion in workers’ compensation patients: a case-control study. Spine (Phila Pa 1976) 2010;35: 1812–7. 32. Nguyen TH, Randolph DC, Talmage J, et al. Long-term outcomes of lumbar fusion among workers’ compensation subjects: a historical cohort study. Spine (Phila Pa 1976) 2011;36:320–31. 33. Paul C, Derrett S, McAllister S, et al. Socioeconomic outcomes following spinal cord injury and the role of no-fault compensation: longitudinal study. Spinal Cord 2013;51:919–25. 34. McAllister S, Derrett S, Audas R, et al. Do different types of financial support after illness or injury affect socio-economic outcomes? A natural experiment in New Zealand. Soc Sci Med Med 2013;85:93–102. 35. Mills H, Horne G. Whiplash—manmade disease? N Z Med J 1986;99:373–4.
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LITERATURE REVIEW
The Influence of No Fault Compensation on Functional Outcomes After Lumbar Spine Fusion Alexander Sheriff Montgomery, Dipl Orth Eng, MRCS, FRCS (Tr and Orth),* John Edward Cunningham, BSc (Hons), MBBS, MClinEpi, FRACS, FAOrthA,† and Peter Alexander Robertson, MD, FRACS‡
Study Design. Prospective cohort study and systematic literature review. Objective. To compare the functional outcomes for lumbar spinal fusion in both compensation and noncompensation patients in an environment of universal no fault compensation and then to compare these outcomes with those in worker’s compensation and nonworkers compensation cohorts from other countries. Summary of Background Data. Compensation has an adverse effect on outcomes in spine fusion possibly based on adversarial environment, delayed resolution of claims and care, and increased compensation associated with prolonged disability. It is unclear whether a universal no fault compensation system would provide different outcomes for these patients. New Zealand’s Accident Compensation Corporation (ACC) provides universal no fault compensation for personal injury secondary to accident and offers an opportunity to compare results with differing provision of compensation. Methods. A total of 169 patients undergoing lumbar spinal fusion were assessed preoperatively, at 1 year, and at long-term follow-up out to 14 years, using functional outcome measures and healthrelated quality-of-life measures. Comparison was made between those covered and not covered by ACC for 3 distinct diagnostic categories. A systematic literature review comparing outcomes in Worker’s Compensation and non-Compensation cohorts was also performed. Results. The functional outcomes for both ACC and non-ACC cohorts were similar, with significant and comparable improvements
From the *St Bartholomews Hospital and The Royal London Hospital, London, England; †The Royal Melbourne Hospital and the Epworth Richmond, Melbourne, Australia; and ‡Department of Orthopaedic Surgery, Auckland City Hospital, Auckland, New Zealand. Acknowledgment date: June 4, 2014. Revision date: December 4, 2014. Acceptance date: February 23, 2015. The device(s)/drug(s) is/are FDA approved or approved by corresponding national agency for this indication. No funds were received in support of this work. Relevant financial activities outside the submitted work: consultancy, payment for lectures, patents, royalties. Address correspondence and reprint requests to Peter Alexander Robertson, MD, FRACS, The Orthopaedic Clinic, Mercy Specialist Centre, 100 Mountain Rd, Epsom 1023, Auckland, New Zealand; E-mail: [email protected] DOI: 10.1097/BRS.0000000000000966
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over the first year that were then sustained out to long-term followup for both cohorts. At long-term follow-up, the health-related quality-of-life measures were the same between the 2 cohorts. The literature review revealed a marked difference in outcomes between worker’s compensation and non–worker’s compensation cohorts with a near universal inferior outcome for the compensation group. Conclusion. The similarities in outcomes of patients undergoing lumbar spine fusion under New Zealand’s universal no fault compensation system, when compared with the dramatically inferior outcomes for these patients under other worker’s compensation systems, suggest that the system of compensation has a major influence on patient outcomes, and that change of compensation to a universal no fault system is beneficial for patients undergoing lumbar fusion surgery. Key words: workers’ compensation, scoring methods, spinal fusion, spondylolisthesis, employment, return to work, literature review, compensation, injuries, spinal stenosis, back pain. Level of Evidence: 2 Spine 2015;40:1140–1147
C
ompensation and litigation have adverse effects on outcomes in lumbar spinal disorders and lumbar surgery, including fusion operations.1 These adverse effects are also found in other orthopedic and nonorthopedic outcomes.2–8 The adverse factors associated with compensation include an adversarial environment; unpredictable outcomes for claimants, delayed claim resolution, exacerbated illness behavior promoting disability payments, psychosocial factors associated with the workplace environment, and evaluation and medical systems that differ from normal clinical care.9,10 Evaluating the possible factors disadvantaging compensation patients is difficult11 as compensation systems are legislated in social policy that reflects national and societal values. Cassidy et al12 observed the effects of a change in compensation for whiplash patients. Claim numbers, time to resolution, pain, function, and claim costs all improved when compensation payments for pain and suffering were removed. Conversion from a tort to a no fault system has also reduced claim incidence in Canada.13 These studies suggest that claimant behavior and outcomes alter with legislative change and, therefore, may differ under differing compensation systems.
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LITERATURE REVIEW
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
In 1974, New Zealand changed its previous tort-based accident liability and compensation system to a universal no fault system under the control of the state run Accident Compensation Commission (ACC). The ACC covers all accidents including workplace, home, sporting, and vehicular accidents. The ACC (later, the Accident Compensation Corporation) is legislated to promote safety, provide both acute and delayed treatment to accident victims, and provide compensation for wage and salary loss. The provision of this “universal compensation” occurred in exchange for removal of the right to sue for personal injury. The system is funded by both employee and employer levies, petrol taxes, and vehicle licensing fees. The employer contributions vary on the basis of injury risk. The ACC legislation has become enshrined in New Zealand society and widely accepted as a positive legislative advance (Table 1). Given that New Zealand’s ACC legislation removed several potential adverse factors that may influence outcomes for compensation patients, a study of outcomes comparing ACC and non-ACC patients, along with Workers Compensation (WC) and Non Workers Compensation (non-WC) patients from other nations, may shed further insight on the merits of a universal no fault compensation system.
The aim of this study was to compare outcomes in patients undergoing lumbar spinal fusion (LSF) dependent on whether or not they were compensated under the ACC system. We then compared functional outcomes in New Zealand’s ACC patients with both WC and non-WC patients outside New Zealand. The initial study is a prospective study of outcomes in a single surgeon practice over a decade. Comparison of ACC patient outcomes with WC outcomes was performed after a systematic literature review of both compensation and LSF.
MATERIALS AND METHODS Functional Outcomes for ACC Lumbar Spinal Fusion Patients For more than 10 years (1997–2006), 428 patients underwent elective LSF under the care of a single surgeon, forming the basis of this study. Functional outcomes scores were collected prospectively before surgery and at 12 months postoperatively. Scores were then collected again at the long-term follow-up (mean: 8 yr, range: 4–14 yr) after surgery. Additional health-related quality of life (HRQOL) measures were collected at the long-term follow-up point.
TABLE 1. Characteristics of New Zealand’s Accident Compensation Corporation (ACC) System Description
A no fault compensation system for personal injury by accident.
Goals
Injury prevention, treatment, rehabilitation, and earnings compensation.
Injury treatment
Acute and delayed medical and surgical care with rehabilitation on a contracted noncapped fee-for-service basis.
Medical accident insurance
ACC provides cover for treatment injury (medical error/malpractice) with treatment- and earnings-related compensation.
Income replacement
Wage and salary replacement at 80% preinjury level until rehabilitation to the workforce. Cases with injuries unable to be returned to work have continuing income replacement.
Claim management
Major claims have integrated client-centric case management by ACC with facilitation of assessment, access to care, and rehabilitation.
Administration
ACC is a state-based agency that is the sole provider of accident insurance. Income is via levies and taxation (see later). The system is fully funded to account for outstanding claims liability.
ACC Income by components
Employee levy—16%; employer levy—22%; general taxation—19%; motor vehicle levy—17%; interest—25%
Societal cost
Levies represent a societal cost of $NZ1000 per person per annum; employee levy is 1.48% of income; employer levy is 1.15% of liable wage/salary (varies dependent on industry risk rating); motor vehicle levy is $335 per vehicle per annum.
Societal benefits
Treatment—30%; income replacement—23%; long-term care—10%. Remaining income invested to fund outstanding future claims liability.
Administration and operating costs
10% of levy revenue.
Controls on medical surgical practice
ACC does not in general limit investigation or treatment. Protocols are rare but guidelines are developed for some conditions with professional body input.
Reimbursement rates for medical and Fee-for-service care with fees estimated at 75% of mean non-ACC rates. surgical care Adapted from 2013 Annual Report, Accident Compensation Corporation. http://www.acc.co.nz/PRD_EXT_CSMP/groups/external_communications/documents/reports_results/annual_report_2013.pdf. ACC indicates Accident Compensation Corporation.
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LITERATURE REVIEW A case was defined as an ACC case if the New Zealand Accident Compensation Corporation accepted the patient’s condition. To compare the functional outcomes of ACC patients with non-ACC patients, patients were selected with diagnoses where there were significant numbers of patients in the ACC and non-ACC cohorts. The 3 diagnoses were isthmic spondylolisthesis, discogenic disease causing low back pain, and foraminal stenosis requiring wide decompression and subsequent fusion. The functional outcome scores used were the Roland Morris Disability Questionnaire (RMDQ) and the low back outcome score (LBOS). The HRQOL measure was the SF-12v2.
Statistical Analysis Analysis of the short and long-term RMDQ difference was performed with the minimal clinically important difference (MCID) threshold set at both 4 and 8 points and reported as percentage of patients achieving the MCID threshold. Two levels of MCID for the RMDQ were selected, as the lower is the recognized MCID,14 yet a higher threshold may be more appropriate for major interventions demonstrating real change in function.15 The LBOS MCID at both time points was set at 7.5 points and reported in the same manner.16 The SF-12v2 surveys were scored using QualityMetric Health Outcomes Scoring Software 3.0 (QualityMetric Incorporated, Lincoln, RI), reporting physical component score and mental component score centiles against 1998 US normative data, and SF-6D R2 score. Statistical analysis of normal continuous variables, the RMDQ and LBOS scores, was by 2-sample paired t test and of binary outcomes; the MCID scores, by tests of proportions. The SF12v2 score domains and SF-6D R2 were compared using the Wilcoxon rank sum test. Missing data and their calculated variables were not considered. A value of P less than 0.05 was considered statistically significant, and analysis was performed using Stata v11, Statacorp LP, TX.
Systematic Literature Review—Functional Outcomes in Lumbar Spine Fusion Patients Covered by Worker’s Compensation
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
TABLE 2. Breakdown of Characteristics of Study
Groups
ACC
Non-ACC
Number
120
49
Male
55%
37%
Age
53 (24–81)
61 (31–82)
1
75
33
2
42
15
3
3
1
Foraminal stenosis
30
9
Isthmic spondylolisthesis
34
20
Painful spondylosis
56
20
Number of levels fused
Diagnosis
ACC indicates Accident Compensation Corporation.
(76: 56 ACC/20 non-ACC), and fusion after wide decompression for spinal stenosis (39: 30 ACC/9 non-ACC). Patient characteristics were matched apart from age where the non-ACC group was older (61 vs. 53 yr, P < 0.05) (Table 2). RMDQ scores (0–24, 24 = maximum disability) revealed severe disability preoperatively in both ACC (mean: 17.2, 16.4–18.0) and non-ACC (15.4, 14.2–16.7, P < 0.05) groups. There was dramatic reduction in disability at the 1-year postoperative mark in both groups (RMDQ mean ACC: 8.0, 6.8–9.2/non-ACC: 4.6, 2.8–6.5, P < 0.05). The improvements between preoperative and 1 year postoperative disability were significant in both groups (P < 0.05). At long-term follow-up, the disability improvement was maintained in both groups, and there was no difference between ACC and non-ACC patients (ACC: 5.9, 4.7–7.1/non-ACC: 3.8, 1.9–5.8, P > 0.05). There was no significant difference between the 1-year and long-term follow-up scores, indicating that the improvement was sustained (Figure 1).
To examine the published influence of compensation upon functional outcomes after lumbar spinal fusion, a systematic literature review was performed. MEDLINE, EMBASE, and the Cochrane Controlled Trials register were searched for “compensation” and “lumbar fusion.” Included studies required compensation patients undergoing LSF, recognized functional outcomes scores, and a minimum of 12 months of follow-up.
RESULTS Surgical Outcomes A total of 169 patients underwent an LSF for the indications described. Seventy-one percent of these were covered by ACC. The patient numbers were isthmic spondylolisthesis (54 patients: 34 ACC/20 non-ACC), discogenic low back pain 1142
Figure 1. Graph of RMDQ scores over time for ACC and non-ACC patients (mean ± 95% confidence interval). Range: 0 to 24, lower scores indicating better function RMDQ indicates Roland Morris Disability Questionnaire; ACC, Accident Compensation Corporation.
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LITERATURE REVIEW Examining the LBOS (0–75, 0 = maximum disability), the preoperative disability and changes with surgery revealed similar findings to the RMDQ. Before surgery, the LBOS indicated significant disability in both groups (ACC: 26.0, 23.8– 28.1/non-ACC: 31.9, 27.6–36.1, P < 0.05). Both groups improved significantly at 1 year (ACC: 43.9, 39.9–48.0/nonACC: 54.1, 48.4–59.9, P < 0.05). Although the non-ACC patients showed better LBOS at 1 year follow-up, they had demonstrated slightly less disability preoperatively. At longterm follow-up, the improvements were maintained and there was no difference between the ACC and non-ACC cohorts (ACC: 47.0, 43.5–50.4/non-ACC: 55.4, 49.3–61.6, P > 0.05) (Figure 2). The proportion of patients reaching the MCID of the RMDQ at the 1-year mark was the same between the ACC and non-ACC patients (MCID 4: ACC 84%, non-ACC 79%, P > 0.05; MCID 8: ACC 57%, non-ACC 72%, P > 0.05). This was similar at the long-term follow-up time point (MCID 4: ACC 91%, non-ACC 91%, P > 0.05; MCID 8: ACC 76%, non-ACC 71%, P > 0.05). Likewise, the proportion of ACC patients reaching the MCID of the LBOS was 74% at the 1-year mark, and 75% at the long-term point, without significant difference from the non-ACC patients (78%/73%, respectively) (Table 3). At long-term follow-up, the SF12v2 revealed no difference in either the physical component score or the mental component score domain scores for the ACC and non-ACC groups (physical component score: ACC 41.6 ± 11.5/non-ACC 44.0 ± 13.0, P > 0.05) (mental component score: ACC 50.3 ± 11.6/non-ACC 52.5 ± 9.9, P > 0.05) (Figure 3). The “whole of health” measure SF-6D R2 was not significantly different between the 2 groups (ACC 0.71 ± 0.17/non-ACC 0.76 ± 0.18, P > 0.05) (Figure 4).
Systematic Literature Review A total of 175 articles were located using the key words, of which only 25 articles discussed functional outcomes. None of these articles came from countries with no fault compensation systems. Of these, 16 articles used recognized functional outcome scores as a component of the assessment.17–32 Functional
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
TABLE 3. Percentage of ACC and non-ACC
Patients Achieving MCID at the 12-Month and Long-term follow-up Time Points, as Measured by the Improvement in RMDQ Scores by 4 and 8, and LBOS by 7.5 ACC MCID%
Non-ACC MCID%
12-mo RMDQ (4)
84
79
12-mo RMDQ (8)
57
72
12-mo LBOS
74
78
Long-term RMDQ (4)
91
91
Long-term RMDQ (8)
76
71
Long-term LBOS
75
73
ACC indicates Accident Compensation Corporation; MCID, minimal clinically important difference; RMDQ, Roland Morris Disability Questionnaire; LBOS, low back outcome score.
scores that had been used included the Oswestry Disability Index, LBOS, Stauffer-Coventry Score, Roland Morris Questionnaire, the SF-36/20/12, and visual analogue scale scores of pain. Ten of the articles presented studies from the United States. All but 2 of the articles from the United States demonstrated better outcomes in the non-WC cohorts. Of the other 2, 1 demonstrated equivalent outcomes in both groups, and the other reported good outcomes in a WC cohort.18,27 Both had major methodological problems. The former did not assess preoperative scores and so could not assess improvement and the latter used as its control group patients who were denied planned surgical treatment and then achieved follow-up of only one-third of the cohort. All articles from other countries demonstrated superior outcomes in the non-WC patient cohort, although Penta and Fraser23 demonstrated that the outcome superiority for the non-WC patients in Australia dissipated at long-term follow-up (Table 4). The negative effects of WC were seen in studies of posterolateral fusion,18,22,31 anterior lumbar interbody fusion,21,23 and posterior lumbar interbody fusion.28 The indications for surgery did not seem to alter the negative influence of WC. Fusion for isthmic spondylolisthesis did equally poorly as the majority of studies that focused on disc degenerative disease.20 When patients were compared in terms of those reaching an MCID, again there was a significant difference between the groups favoring the non-WC cohort.31
DISCUSSION Figure 2. Graph of LBOS scores over time for ACC and non-ACC patients (mean ± 95% confidence interval). Range: 0 to 75, higher scores indicating better function. LBOS indicates low back outcome score; ACC, Accident Compensation Corporation. Spine
Determination of the influence of compensation upon outcomes in spinal pathologies presents significant challenges. Compensation status is predetermined by the local accident liability legislation. Thus, compensation and relative variables cannot be randomized, and as with other sociopolitical factors, its role must be deduced by cohort observation. www.spinejournal.com
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LITERATURE REVIEW
Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
Figure 3. PCS and MCS of SF-12v2, for ACC and non-ACC patients, measured at long-term followup. There was no significant difference between the scores of the ACC and non-ACC patients. PCS indicates physical component score; MCS, mental component score; ACC, Accident Compensation Corporation.
Studies in whiplash have shown that changes in compensation delivery significantly effect claimant behavior, outcomes, and costs.12 The literature strongly suggests that compensation has adverse effects upon LSF, yet the effect of differing types of compensation is unclear. New Zealand’s ACC is a universal no fault system of compensation that covers medical and rehabilitation costs, with provision of 80% replacement of income. It offers care and income stability in the context of a time of potential financial and psychosocial upheaval for the patient. In this respect, the ACC differs from other workers’ compensation and litigation environments where multiple adversarial factors have been identified. Adversarial systems that have unpredictable and delayed outcomes, legal representation, enhanced disability behavior to achieve financial gain, and models of care that differ from the norm are all likely to play a role in limiting access to care and rehabilitation, delaying return to normality. Although it is virtually impossible to study individual compensation characteristics that may disadvantage the injured patient, a study of outcomes of ACC and comparison with
Figure 4. SF-6D scores for ACC and non-ACC patients, measured at long-term follow-up. There was no significant difference between the scores of the ACC and non-ACC patients. ACC indicates Accident Compensation Corporation.
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WC and non-WC cohorts allows comparison of the effects of major legal and social differences between states and countries. LSF continues to be an operation with variable outcomes. The disability and psychosocial comorbidities in these patients are high. Given the outcome inconsistency, LSF represents an ideal procedure for study of the influence of compensation variations. This study has strongly suggested that the universal no fault compensation system in New Zealand does not disadvantage patients to the extent that compensation does elsewhere. Although ACC and non-ACC patients were highly disabled before surgery, both groups made comparable significant improvements with fusion surgery and at long-term follow-up were equivalent. The HRQOL measures were equal to the normal population. Attempting to compare New Zealand’s ACC patients with WC patients from other jurisdictions becomes more challenging. The literature is generally retrospective. Different outcome assessment tools have been used, some of which are widely accepted17,31 and some apparently custom designed.18 Variable diagnoses were included24,30,31 or the diagnosis before surgery was unclear.26 When comparisons were made with other cohorts, the control groups varied. WC patients are compared with non-WC patients undergoing spinal fusion.30 Other control groups include differing operative procedures,17 nonoperative patients,32 or patients whose surgical treatment was denied.18 Poor follow-up rates render some outcomes questionable.18 It is very clear in all studies that functional outcomes in WC patients undergoing LSF tend to be poor, and where comparison is made with non-WC cohorts, the implication is that the compensation is a major factor in the poorer performance of the WC group. The difficulties comparing outcomes across differing studies with differing outcome assessment tools would be reduced by the widespread use of MCIDs. Sporadic use has confirmed that this parameter also reveals WC to be an adverse effect.31 The use of MCIDs for our study of ACC and non-ACC outcomes demonstrates a much more robust improvement in
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Spine
SPINEI1404_LR 1145
2010
United States
United States
Nguyen et al32 2011
R
R
CC
P
R
P
R
RCT
R
R
P
R
P
P
R
P
Design
PLF
PLF/PLIF/ ALIF
PLF
PLF
PLIF
ALIF/PLIF
DS
DS
DS
DS/FS
DS
DS
DS
DS
PLF/PLIF / ALIF PLF
DS
DS
DS
DS
DS
DS
IS
DS
725
22
60
155
71
49
185
294
36
73
81
24
103
151
26
17
12
60
24
24
12
24
24
24
12
24
24
18
240
24
25
12
Number FollowDiagnosis of Patients up (mo)
PLF
ALIF/PLF
ALIF/PLF
PLF
ALIF
ALIF
PLF
PLF
Surgery
Disability
VAS/ODI
ODI/SF-36/VAS
Higher disability in WC than in control group
WC was a predictor for poor outcome
WC has significantly less improvement
WC worse in terms of relief of leg pain
WC results comparable with normative data scores
SF-36/patient satisfaction SF-36/VAS/ODI
WC had significantly worse outcomes
Poor results with a 24% reoperation rate
WC patients had inferior results
WC had significantly lower SF-36.
Non-WC associated with progression of symptoms
Good results in 91% of WC patients
WC strongly associated with poor operative results
WC worse at 2 years but dissipates over 10 yr
WC-significant prognostic factor in outcomes
WC had a profoundly negative influence on outcome
43% of WC patients had no relief of pain or made worse
Results
ODI/VAS
RMDQ/SCI/SF-20
VAS/ODI
SF-36
NOQ
VAS
Outcome rating
LBOS
LBOS
Functional results
Pain score
Outcomes
P indicates prospective; PLF, posterolateral fusion; DS, degenerative spondylolisthesis; WC, Workers Compensation; R, retrospective; IS, isthmic spondylolisthesis; ALIF, anterior lumbar interbody fusion; LBOS, low back outcome score; VAS, visual analogue scale; NOQ, NASS Outcome Questionnaire; SF-36, Short-Form 36 Multidimensional Health Survey; RCT, randomized controlled trial; PLIF, posterior lumbar interbody fusion; ODI, Oswestry Disability Index; RMDQ, Roland Morris Disability Questionnaire; SCI, Stauffer-Coventry-Index; SF-20, Short-Form 20 Multidimensional Health Survey; FS, foraminal stenosis; CC, case control.
South Korea
Kong et al30
Carreon et al 2010
2006
United States
31
Trief et al29
2003
United States
2003
Schiffman et al27
Madan and Boeree28
2001
United Kingdom
Sweden
Fritzell et al25
2001
2001
United States
Hodges et al17
2000
1997
1997
1997
United States
United States
Slosar et al24
Deberard et al26
United States
Hinkley and Jaremko18
Australia
Penta and Fraser23
United States
1994
United Kingdom
Greenough et al21
Vaccaro et al22
1988
United States
Hanley and Levy20
1984
Canada
Dzioba and Doxey et al19
Year
Country
Authors
Fusion
TABLE 4. Studies Identified Comparing Workers’ Compensation and Nonworkers’ Compensation Outcomes After Lumbar Spinal
LITERATURE REVIEW Influence Compensation Outcomes Lumbar Fusion • Montgomery et al
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LITERATURE REVIEW spinal fusion across both cohorts, with MCIDs ranging from 57% to 91% dependent on the outcome score and follow-up. The strengths of this study include prospective collection of recognized functional outcome scores, both short and longterm follow-up out to 14 years, and a high rate of follow-up. The clear diagnostic categories with significant numbers of both ACC and non-ACC cases allow generalizability across both groups for diagnoses in the injury population. The study of a single surgeon practice is advantageous with consistent indications and techniques. The weaknesses of the study include the absence of HRQOL measures at the outset. This is in part because of the duration of the study with long-term follow-up. HRQOL measures were not in widespread use at the commencement of this study period. Because New Zealand’s ACC system includes all personal injuries as a result of accident, the study includes not only work injury but also vehicle, home, and sport injuries. It is possible that these latter injury activities may result in differing prognoses within a compensation system and lessen the perceived advantages of a universal no fault system specifically upon workplace injuries. There is no direct evidence of any difference in outcomes between work and nonworkplace injuries although accurate data are lacking. It is also clear that the vehicle injuries result in similar adverse effects on outcome in the compensated patient. The universality of the ACC system has lessened the focus on the location of injury, whereas these relevant liability details are likely to be carefully examined in an adversarial system. The benefits of the universal no fault compensation system have been demonstrated in other areas of injury treatment and rehabilitation. Economic status and return to work are better for ACC patients than for non-ACC patients with spinal cord injury33 and when major trauma patients are compared with disabling medical problems.34 ACC also seems to minimize whiplash as a long-term clinical problem.35 New Zealand’s ACC system has been subject to change and modification since its introduction 40 years ago, and these important changes must be acknowledged. Modest schedule-based payments for pain and physical impairment were an early feature of the scheme but ceased prior to this study. Acceptance of the definition of injury (the diagnosis of structural abnormality) and of accident has come under greater scrutiny. This has occurred subsequent to the study period. It is also accepted that the political leanings of the government of the day influence the ease or otherwise of obtaining coverage and benefit payment. Despite these variations in legislative and political flavor, the application of a universal no fault system providing care and economic compensation is unchanged. This study has not addressed any economic benefits and has not focused upon return to work. Although it is reasonable to conclude that improved function equates to gainful employment, the confounding variables of economic activity and opportunity may render return to work data less reliable than functional outcome measures when determining the real gains or otherwise for compensation and noncompensation patients. 1146
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In summary, the universal no fault compensation system that exists for accident and injury victims in New Zealand seems to offer considerable advantage for patients whose condition requires treatment with LSF. This advantage is in terms of improved functional outcomes. The ACC patients achieve equivalent improvements to the non-ACC patients and improvements equivalent to the non-WC patients in the published literature. They also achieve function that is considerably better than that achieved in WC patients in adversarial compensation jurisdictions.
➢ Key Points In a universal no fault compensation system, patients undergoing lumbar spine fusion improve functionally in both the short and long term and are equivalent to the noncompensated patients. Conversely, literature review demonstrates that worker’s compensation patients in adversarial systems achieve significantly worse outcomes when compared with nonworker’s compensation patients. Compensation systems have a profound effect on the functional outcomes for lumbar spine fusion patients, and there are major advantages with a universal no fault system.
References
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LITERATURE REVIEW 12. Cassidy JD, Carroll LJ, Côté P, et al. Effect of eliminating compensation for pain and suffering on the outcome of insurance claims for whiplash injury. N Engl J Med 2000;342:1179–86. 13. Lemstra M, Olszynski WP. The influence of motor vehicle legislation on injury claim incidence. Can J Public Heal 2004;96:65–8. 14. Ostelo RWJG, de Vet HCW. Clinically important outcomes in low back pain. Best Pract Res Clin Rheumatol 2005;19:593–607. doi: 10.1016/j.berh.2005.03.003. 15. Patrick DL, Deyo RA, Atlas SJ, et al. Assessing health-related quality of life in patients with sciatica. Spine (Phila Pa 1976) 1995;20:1899–908; discussion 1909. 16. Khatri M, Murray M, Greenough CG. Minimum clinically important difference in low back outcome score in individuals with low back pain. J Bone Joint Surg Br Vol 2004;86-B(supp II):115. 17. Hodges SD, Humphreys SC, Eck JC, et al. Predicting factors of successful recovery from lumbar spine surgery among workers’ compensation patients. J Am Osteopath Assoc 2001;101:78–83. 18. Hinkley BS, Jaremko ME. Effects of 360-degree lumbar fusion in a workers’ compensation population. Spine (Phila Pa 1976) 1997;22:312–23. 19. Dzioba RB, Doxey NC. A prospective investigation into the orthopaedic and psychologic predictors of outcome of first lumbar surgery following industrial injury. Spine (Phila Pa 1976) 1984;9:614–23. 20. Hanley EN, Levy JA. Surgical treatment of isthmic lumbosacral spondylolisthesis. Analysis of variables influencing results. Spine (Phila Pa 1976) 1988;14:48–50. 21. Greenough CG, Taylor LJ, Fraser RD. Anterior lumbar fusion. A comparison of noncompensation patients with compensation patients. Clin Orthop Relat Res 1994;300:30–37. 22. Vaccaro AR, Ring D, Scuderi G, et al. Predictors of outcome in patients with chronic back pain and low-grade spondylolisthesis. Spine (Phila Pa 1976) 1997;22:2030–5. 23. Penta M, Fraser RD. Anterior lumbar interbody fusion. A minimum 10-year follow-up. Spine (Phila Pa 1976) 1997;22:2429–34. 24. Slosar PJ, Reynolds JB, Schofferman J, et al. Patient satisfaction after circumferential lumbar fusion. Spine (Phila Pa 1976) 2000;25:722–6.
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