Acute and chronic low back pain: Cognitive, affective, and behavioral dimensions.

Despite strong suppositions concerning differences between patients suffering acute and chronic low back pain, relatively few data-based comparisons have been made. In this study, affective, cognitive, behavioral, and demographic contrasts were conducted. Chronic patients were divided into those who demonstrated signs and symptoms that were either congruent or incongruent with underlying anatomical and physiological principles. Low SES, compensation claims, use of opiate analgesics, greater disability, catastrophizing cognitions, stronger emotionality, and passive coping were more characteristic of both acute and chronic incongruent patients than chronic congruent patients. A relatively stereotyped, spontaneous facial expression of pain was observed in all groups when responding to painful movements during a physical examination. The similarities between acute and chronic incongruent patients have implications for the assessment and treatment of low back pain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential efficiency of expression of humanized antibodies in transient transfected mammalian cells

BACKGROUND: Wide variations in disability duration and magnitude have been noted among recipients of workers' compensation for low back pain. Findings from recent studies have indicated that inclusion of a broad array of variables (i.e., physical, occupation, social, economic) is needed to understand differences in workers' responses to occupational low back pain. METHODS: Workers' compensation and questionnaire data from 340 Oregon workers with low back claims were merged to develop multivariate models predicting: (1) absenteeism days, (2) residual symptoms, (3) functional impairment, and (4) medical costs. RESULTS: Forty-two percent of the variation in low back symptoms was explained by: discontinuing physical fitness activities post-injury (beta = -.419), self-reported low energy/high fatigue (beta = -.227), poorer general health (beta = .137), and attorney involvement in claim (beta = .117), (adjusted R2 = .418, p < 0.001). Survival curves revealed significantly longer claim durations among workers who discontinued physical fitness activities post-injury, compared with workers who did not; these differences remained significant even after controlling for severity of the initial injury. CONCLUSION: Continuation of physical fitness activities during the recovery process was found to be a significant predictor in three of four regression models, providing evidence on behalf of a relationship between fitness and positive health outcomes. However, it was not possible to clearly differentiate pre-morbid from post-injury fitness, nor to determine if this relationship was due to a therapeutic effect on the back, the general restorative benefits of remaining active, or represents a proxy variable for workers' self-care efforts during recovery.     

Predictors of outcome in patients with chronic back pain and low-grade spondylolisthesis

STUDY DESIGN: Retrospective case series. OBJECTIVES: To determine the factors influencing symptom relief after uninstrumented posterolateral spinal fusion with or without decompression in adult patients with chronic back pain and previously asymptomatic low-grade isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: The role of previously asymptomatic low-grade isthmic spondylolisthesis in chronic adult low back pain is unclear. Operative intervention in this setting is controversial. METHODS: Twenty-four consecutive adult patients with chronic low back pain and low-grade isthmic spondylolisthesis first detected during routine work-up of new onset low back pain underwent spinal fusion with or without decompression. The influence of active worker's compensation or litigation claims, radicular pain, concomitant laminectomy, age, gender, fusion to L4, intervertebral disc bulge, and pseudarthrosis were investigated. RESULTS: All 13 patients involved in worker's compensation claims or pending litigation had fair or poor results. Nine of 11 patients without such issues had good or excellent results. Although the strong association of worker's compensation with poor results made it difficult to assess the importance of other risk factors, the data suggest that good results may be more likely in patients with radiculopathy who undergo laminectomy. CONCLUSIONS: This investigation, although limited by a number of factors including small sample size and retrospective, unblinded review, suggests that active worker's compensation and litigation issues are associated strongly with poor results of operative management for chronic low back pain in adult patients with low-grade spondylolisthesis.     

Assessment of spinal musculature using surface electromyographic spectral color mapping

STUDY DESIGN: A technique is described for analyzing electromyogram data from lumbar spinal muscles, with special reference to discrimination of people with back pain. The ability to discriminate was evaluated in 99 people (61 healthy and 38 with chronic or acute back pain), and the influence of load was assessed. OBJECTIVES: To evaluate methods of analysis of complex electromyogram data and to assess correlation of electromyogram information with clinical condition in people with and without back pain. SUMMARY OF BACKGROUND INFORMATION: In previous analyses of electromyogram data, only a small part of the data have been used. Spinal muscular decompensation has been postulated in chronic low back pain, but there has been no direct demonstration of this phenomenon. Objective measures are still elusive. METHODS: Lumbar spinal surface electromyograms were recorded during an isometric lifting task. The data were represented graphically as color-coded plots of electromyogram frequency, time, and electromyogram amplitude. Spectral width at half-peak amplitude (spectral half width) was calculated from the digitized, summed data. Ninety-nine people were tested: 48 men (29 with no recent [in the past 2 years] history of back pain, 16 with chronic back pain, 3 with acute back pain) and 51 women (32 with no recent back pain and 19 with chronic back pain). RESULTS: Spectral color maps in people with chronic back pain were markedly different from those in healthy people. Spectral half width was greater in people with chronic back pain than in healthy people (P < 0.01). Blinded analysis of spectral color maps allowed discrimination of people with back pain from healthy people with a sensitivity of 76% and a specificity of 81%. People with a history of back pain had markedly variable half widths. CONCLUSIONS: A new method of analysis of electromyogram data from lumbar spinal muscles has allowed discrimination between people with back pain and healthy people. This provides direct evidence of a correlation between muscular electrical function, measured by electromyogram, and low back pain. This technique may have potential as an objective measurement tool.     

Enhancement of varicella-zoster virus infection in cell lines expressing ORF4- or ORF62-encoded proteins

The objective of this study was to determine the effect of a change in back-support-use policy on the occurrence of work-related low back injuries among a large cohort of employees in the retail-trade home improvement industry. Working hours of exposure, back support use, and intensity of materials-lifting requirements were collected from 1989 through 1994. Records of injury-related claims were reviewed for all documented injuries to the lower back among members of the cohort during the same period. Over 101,000,000 working hours were recorded by nearly 36,000 employees; 2,152 employees reported an acute low back injury occurring during working hours as a first report of episode, with medical-physician diagnosis and acute/abrupt onset. Incidence density rates were calculated for persons wearing and not wearing the back support. Rate ratios and prevented fractions were evaluated. Before implementation of a company-wide back-support policy, the employees had a rate of acute low back injuries of 30.6 per million working hours. After implementation, this rate fell to 20.2 per million working hours, a significant reduction of 34.0%. This effect was seen in both genders, in younger workers and in those aged 55+, with low levels of lifting as well as high lifting intensities, and in persons with one to two years of employment with the company. The authors conclude that uniform mandatory implementation of a back-support-use policy significantly reduces the incidence of acute low back injuries incurred in the workplace.     

Meteorological conditions and self-report of low back pain

STUDY DESIGN: Six months of daily low back pain ratings for 94 individuals were tested for the influence of prevailing weather conditions during the spring, summer, and fall seasons. Intergroup differences were tested for study participants who reported weather sensitivity and for those who did not. OBJECTIVES: To investigate the relation between pain ratings and prevailing weather conditions in a population with chronic or recurrent low back pain. SUMMARY OF BACKGROUND DATA: Weather conditions have been reported to influence pain perception in some disease states, including low back pain. Investigations of this relation in chronic or recurrent low back pain have involved varied methodologies, and conflicting results have been reported. METHODS: The effects of eight weather variables reported to influence musculoskeletal pain were tested on daily pain ratings. A post hoc weather sensitivity questionnaire was used to disperse 73 individuals into groups based on perceived weather sensitivity, and group differences were tested. RESULTS: Significant effects on pain scores were found, most notably for temperature and vapor pressure. The magnitude of the effects were small compared with autocorrelation of an individual's own pain scores. Significant differences were found between the group of individuals who were insensitive to weather conditions and that of individuals with perceived sensitivity to cold temperatures. No significant intergroup differences were found for damp, rainy conditions or changes in barometric pressure. CONCLUSIONS: Weather conditions may influence subjective reporting of low back pain significantly. Although the effects are small in magnitude, they should be considered in clinical treatment of the patient with chronic, nonspecific low back pain. Pain scores may demonstrate greater interaction with certain weather conditions in individuals perceiving sensitivity to those conditions.     

Relation between socioeconomic status, employment, and health during economic change, 1973-93

OBJECTIVE: To investigate the association between the national unemployment rate and class differences in the relation between health and employment during the period 1973-93. DESIGN: Data from general household surveys, 1973-93. Comparison of rates of employment, unemployment, and economic inactivity among those with and without limiting longstanding illness in different socioeconomic groups and how these varied over 20 years. SUBJECTS: All men aged 20-59 years in each survey between 1973 and 1993. MAIN OUTCOME MEASURES: Change over time in class specific rates of employment, unemployment, and economic inactivity in those with and without limiting longstanding illness. RESULTS: Men in socioeconomic groups 1 and 2 with no longstanding illness experienced little decrease in their chances of being in paid employment as the general unemployment rate rose. Those most affected were men in manual groups with limiting longstanding illness. The likelihood of paid employment was affected far less by such illness in non-manual than in manual groups. In group 1 about 85% of men with such illness were in paid employment in 1979 and 75% by 1993; in group 4 the equivalent proportions were 70% and 40%. In men in manual groups with limiting longstanding illness there was no sign of employment rates rising again as the economy recovered. CONCLUSION: Socioeconomic status makes a large difference to the impact of illness on the ability to remain in paid employment, and this impact increases as unemployment rises. Men with chronic illness in manual occupations were not drawn back into the labour force during the economic recovery of the late 1980s.     

The need for accurate target and dose specifications in conventional and conformal radiation therapy--an introduction

Back pain in children has long been considered a serious condition with an organic cause. The staff of the Shriner's Hospital had been informally noting that diagnoses among children with back pain had been changing. We conducted a retrospective study of 648 patients with spinal disorders treated at the Shriner's Hospital for Crippled Children, Spokane Unit, between January 1991 and June 1993. The patients were divided into two groups: those with pain and those without pain. It was found that back pain with no organic cause was the primary diagnosis in 57% of the group having pain. Only one child had a diagnosis of malignancy, and there were no cases of active infection. In the group with pain, three interesting associations were found concerning psychosocial problems, disability, and litigation. It was found that the diagnoses in children with back pain treated at this referral center during the study period parallel those in the adult population with back pain.     

Trends in disability duration and cost of workers' compensation low back pain claims (1988-1996)

Previously published epidemiologic studies of low back pain (LBP) have reported that the prevalence of low back disability has increased dramatically. These studies based their findings on either the number of disability claims filed, the disability duration, or both. This information was from countries other than the United States or from the US Social Security Disability Insurance data, with findings reported only to the early 1980s. More recent studies of US workers' compensation LBP claims reported a decrease in the incidence rate from the late 1980s to the mid-1990s. No studies have been found that report on the trends of disability duration for workers' compensation LBP claims. This study examined recent trends in the length of disability (LOD) for LBP claims and associated costs, using a large sample of claims from the privately insured US workers' compensation market. LOD and cost information were derived for injuries from 1988, 1990, 1992, 1994, and 1996. For each year, the distributions of LOD and cost were skewed, with the small percentage of claims that lasted more than one year (4.6%-8.8%, depending on the year) accounting for a large percentage of the total disability days (77.6%-90.1%) and cost (64.9%-84.7%). From 1988 to 1996, the average LOD decreased 60.9%, from 156 days to 61 days. The probability of being on disability for a long period of time has decreased over the years. Over the study period, the average cost of a claim decreased 41.4%, while the median cost increased 19.7%. The most influential change in the LOD and cost distributions was a reduction in expensive claims with a long disability duration. The evolution of LOD and cost is also detailed for different disability durations for the study period.     

Construction Contractors' Claim Process Framework

The management of construction claims is the greatest challenge that is facing contractors in today's vacillating business environment. Construction projects are becoming increasingly susceptible to a variety of factors that give rise to time extension and cost recovery. Although the construction business environment has moved toward partnering arrangements in recent years, the number of contractual difficulties continue to rise. Thus, the construction industry needs to develop methodologies for construction claim management that should overcome their current problems. While some practitioners have been using some kind of a procedure for claim management process framework measuring tool, a written exposition of such an instrument is not widely available in the literature. This paper presents the principles that underly construction claim process and gives a generic framework that aims at facilitating measurement of construction claim process as one of the strategies for improving construction business processes. It also presents a survey of Malawian construction contractors' performance on the construction claim process framework. The results show a low awareness of such a construction claim process-measuring instrument.     

Essential promoter elements are located within the 5'' untranslated region of human insulin-like growth factor-I exon I

The connection between work-related exposures and the onset of back injury or pain is complex and not clearly understood. This paper raises design issues related to the planning and conduct of cohort studies of industrial low back pain (or injury)(LBP), with care given to definition and measurement of exposure and outcome events. These issues include sample size, outcome definition, study biases, and practical considerations when seeking and maintaining company collaboration with a research effort. Without resolving these issues, the authors conclude: (1) cohort studies of worksite-based LBP are needed to elucidate the causal associations between work tasks and LBP onset, (2) both acute and cumulative exposures should be assessed as risk factors for low back injury or pain, and (3) attention should be paid to the planning of such studies and minimization of potential biases that can limit the validity of the results. These design issues will benefit researchers and companies engaged in the planning and conduct of cohort studies of industrial LBP.     

Evaluation of disability pensions by a medical polyclinic: 1990-1995

The question if and in what manner changes of the labour market, in first line increasing unemployment, may influence the composition of the collective demanding a disability pension on one hand and the diagnoses relevant for assessment of requests on the other hand have been investigated as well as possible influences on the criteria for assessments. To this end all expert reports elaborated by the Medical Outpatient Clinic of the University Hospital of Zürich and submitted to the disability insurance between 1990 and 1995 have been evaluated retrospectively. The results show that the fraction of men remained stable around 70% over the whole observation period. The number of persons employed in auxiliary functions remained also constantly high. Over the whole period of observation there was a high, growing percentage of foreign applicants. The most marked change during the observation period was a significant increase of unemployment in the collective. This increase particularly affected applicants with higher ranking jobs or persons over 50. Foreigners became an important part of the unemployed applicants. Rheumatoid disorders and "back pain" in particular were of increasing importance among the relevant diagnoses for assessment of disability. There was a significant decline in the extent of invalidity acknowledged in marked contrast to our initial expectation that the strictness of the applied criteria would weaken when confronted with an increasing number of applications.     

Predicting work stress compensation claims and return to work in welfare workers.

Occupational stress is prevalent in work areas in which there is high contact with distressed or dependent members of the public. However, little is known about the prediction and management of stress-related compensation claims, which can be expensive for employers. The authors interviewed all staff members of a large public sector welfare agency who had made a compensation claim for work-related stress during a 12-month period (N?=?19) and obtained in-depth information from 16 of the 17 who were still available. A clear relationship was found between type of stress precipitant and length of stress-related leave, suggesting that the organizational response to specific stressful incidents was much more effective than its response to chronic work stressors. Demographic data for all 19 claimants showed that they had taken twice as many days of sick leave as the organizational average in the year preceding their claim. There are important implications for personnel management practices that may reduce and prevent work stress for vulnerable workers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The course of back pain in primary care

STUDY DESIGN: Review paper of outcome studies among primary care back pain patients. OBJECTIVES: To determine the short-term and long-term pain and functional outcomes of patients with back pain who are seeking treatment in primary care settings. SUMMARY OF BACKGROUND DATA: Back pain has been viewed as running either an acute or a chronic course, but most patients experience recurrent back pain. This review summarizes outcome studies in light of the episodic course of back pain. METHODS: Studies reporting pain and functional outcome data for consecutive primary care patients with back pain were reviewed. RESULTS: Back pain among primary care patients typically is a recurrent condition for which definitions of acute and chronic pain based on a single episode are inadequate. Because a majority of patients experience recurrences, describing only the outcome of the initial back pain episode may convey a more favorable picture of long-term outcome than warranted. For the short-term follow-up evaluation, most patients improve considerably during the first 4 weeks after seeking treatment. Sixty-six percent to 75% continue to experience at least mild back pain 1 month after seeking care. At 1 month, approximately 33% report continuing pain of at least moderate intensity, whereas 20-25% report substantial activity limitations. For the long-term follow-up (1 year or more) period, approximately 33% report intermittent or persistent pain of at least moderate intensity, one in seven continue to report back pain of severe intensity, and one in five report substantial activity limitations. CONCLUSION: Results from existing studies suggest that back pain among primary care patients typically runs a recurrent course characterized by variation and change, rather than an acute, self-limiting course.     

Occupational upper extremity disorders in the federal workforce. Prevalence, health care expenditures, and patterns of work disability

Upper extremity disorders (UEDs) account for a significant number of work-related illnesses in the US workforce. Little information exists on the distribution of UEDs, their associated health care and indemnity costs, or patterns of work disability. The study presented is an analysis of upper extremity claims within the federal workforce. In this study, the universe consisted of all claims accepted by the US Department of Labor, Office of Workers' Compensation Programs (OWCP), from October 1, 1993, through September 30, 1994. A total of 185,927 claims of notices of injury were processed during the study period, and of these, 8,147 or 4.4% had an UED diagnosis coded according to the International Classification of Diseases, Clinical Modification (ICD-9-CM). 5,844 claims involved a single UED diagnosis and were the only claims field by these employees between October 1, 1990, and September 30, 1994. These single claims with single diagnoses comprised the sample for further analysis. Mononeuritis and enthesopathies of the upper limb were the most common diagnoses, accounting for 43% and 31% of the claims, respectively. Women had a higher proportion of carpal tunnel syndrome, "unspecified" mononeuritis, and "unspecified" enthesopathies. The majority of claimants for both the mononeuritis- and enthesopathy-related diagnoses were between 31 and 50 years of age, received only health care benefits, and did not incur wage loss. Health care costs for mononeuritis and enthesopathy claims were $12,228,755 (M = $2,849). Carpal tunnel syndrome (CTS) and enthesopathy of the elbow were the most costly diagnoses, accounting for 57% and 16% of the total, respectively. Surgical services represented the highest expenditures in CTS claims. Physical therapy accounted for the majority of health care costs for enthesopathy cases. The mean number of workdays lost for CTS and enthesopathy claims were 84 and 79, and the average indemnity costs were $4,941 and $4,477, respectively. These findings indicate that while UEDs represent a relatively small percentage of all workers' compensation cases, the health care and indemnity costs are considerable. Also mean duration and pattern of work disability revealed that these disorders can result in chronic work disability similar to that observed in low back pain. The results highlight the need to determine whether interventions that account for the majority of costs significantly impact long-term outcomes. There is also a need to identify risk factors for prolonged disability in those who experience problems with delayed recovery.     

The impact of unemployment on health: a review of the evidence

OBJECTIVE: To review the scientific evidence supporting an association between unemployment and adverse health outcomes and to assess the evidence on the basis of the epidemiologic criteria for causation. DATA SOURCES: MEDLINE was searched for all relevant articles with the use of the MeSH terms "unemployment," "employment," "job loss," "economy" and a range of mortality and morbidity outcomes. A secondary search was conducted for references from the primary search articles, review articles or published commentaries. Data and definitions of unemployment were drawn from Statistics Canada publications. STUDY SELECTION: Selection focused on articles published in the 1980s and 1990s. English-language reports of aggregate-level research (involving an entire population), such as time-series analyses, and studies of individual subjects, such as cross-sectional, case-control or cohort studies, were reviewed. In total, the authors reviewed 46 articles that described original studies. DATA EXTRACTION: Information was sought on the association (if any) between unemployment and health outcomes such as mortality rates, specific causes of death, incidence of physical and mental disorders and the use of health care services. Information was extracted on the nature of the association (positive or negative), measures of association (relative risk, odds ratio or standardized mortality ratio), and the direction of causation (whether unemployment caused ill health or vice versa). DATA SYNTHESIS: Most aggregate-level studies reported a positive association between national unemployment rates and rates of overall mortality and mortality due to cardiovascular disease and suicide. However, the relation between unemployment rates and motor-vehicle fatality rates may be inverse. Large, census-based cohort studies showed higher rates of overall mortality, death due to cardiovascular disease and suicide among unemployed men and women than among either employed people or the general population. Workers laid off because of factory closure have reported more symptoms and illnesses than employed people; some of these reports have been validated objectively. Unemployed people may be more likely than employed people to visit physicians, take medications or be admitted to general hospitals. A possible association between unemployment and rates of admission to psychiatric hospitals is complicated by other institutional and environmental factors. CONCLUSIONS: Evaluated on an epidemiologic basis, the evidence suggests a strong, positive association between unemployment and many adverse health outcomes. Whether unemployment causes these adverse outcomes is less straightforward, however, because there are likely many mediating and confounding factors, which may be social, economic or clinical. Many authors have suggested mechanisms of causation, but further research is needed to test these hypotheses.     

Forgetting sexual trauma: What does it mean when 38% forget?

L. M. Williams (1994) has shown that many women who were sexually abused as children do not report the abuse when questioned 2 decades later. These findings do not support certain freely made claims about memory, but they do support other claims. The findings do not provide cogent support for the claim that a long stream of childhood sexual traumas is routinely banished from conscious awareness and then can be reliably recovered later. The findings do support the claim that many children can forget about a sexually abusive experience from their past. Extreme claims such as "if you were raped, you'd remember" are disproven by these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exercises: which ones are worth trying, for which patients, and when?

STUDY DESIGN: Criteria-based review. SUMMARY OF BACKGROUND DATA: Reviews based on trials published up to 1990 conclude that the efficacy of exercise therapy in patients with low back pain is questionable. OBJECTIVES: To determine from recently published trials the efficacy of exercises in patients with acute, subacute, or chronic back pain. METHODS: A Medline search for randomized trials concerning exercise therapy in patients with back pain published from 1991 until the first quarter of 1995 was conducted. All studies were given a method score (maximum, 100 points). RESULTS: Eleven randomized trials were included: four in acute back pain, one in subacute, and six in patients with chronic back pain. Three trials had method scores lower than 40 points. For acute back pain, two trials with high method scores (> 50 points) reported no efficacy of flexion or extension exercises; two trials of the McKenzie type of exercises reported positive results but had low method scores. For subacute pain, one trial (> 50 points) reported positive results of exercises with a graded activity program. For chronic back pain, three trials reported positive results with different types of exercises; two trials reported better results with intensive exercising compared with low grade exercising, but after 12 months, this effect had disappeared. In chronic pain, no relation between method score and conclusions could be found. CONCLUSIONS: In acute back pain, exercise therapy is ineffective, whereas in subacute back pain, exercises with a graded activity program, and in chronic back pain, intensive exercising, deserve attention. More research on McKenzie therapy, on exercises with a graded activity program, and on different types of exercising in patients with chronic back pain is necessary.     

Socioeconomic incidences and prognostic factors of low back pain caused by occupational injuries among the hospital personnel of Grenoble University Hospital Center

Low back pain is generally believed to be common among hospital employees. This cross-sectional, retrospective study was carried out to determine the annual incidence of low back pain ascribable to occupational injuries in hospital employees and to evaluate factors influencing the prognosis of these injuries. In 1989, 70 employees working at the Grenoble Teaching Hospital (GTH) reported an occupational injury responsible for low back pain. Each of these employees filled out an epidemiological questionnaire during a routine evaluation by a rheumatologist. Overall annual incidence of occupational injuries with subsequent low back pain was 1.9% among GTH employees. Higher incidences were seen among employees whose occupations involved patient transfer, as well as among nursing assistants. Activities associated with an increased risk of low back pain included handling of patients or objects and work requiring prolonged periods in uncomfortable positions or in the standing position. A previous history of low back disease and a longer period of time in the current work were also associated with an increased risk of low back pain. Characteristic clinical profiles of patients with low back pain subsequent to occupational injury were determined by occupation and type of hospital department. The analysis of long-duration absence from work and long-term consequences on career confirmed the significant adverse socioeconomic impact of these injuries.     

Subcontractor Schedule Control Method

Trade coordination and claims documentation is a challenge on any project, particularly for specialty subcontractors. The writers introduce a schedule control method initiated by the subcontractor, which facilitates coordination and communication between a subcontractor and other project participants as well as documentation to the prime contractor. A case study illustrates the preparation of a trade-specific critical path method (CPM) schedule, which is updated on a regular basis. The writers also address the interrelationship between the CPM schedule, internal reporting, schedule of values, and labor tracking. It is difficult to ensure that all subcontractor-produced documentation is complementary, but it is well worth the effort when it comes to supporting a claim. Monthly schedule updates and narratives communicate the conflicts, issues, and schedule constraints the subcontractor experiences or anticipates on a project, thereby providing contractually required notice to the prime contractor during the project. This increases the likelihood of resolving issues during the project, while simultaneously protecting a subcontractor’s position if change order requests are denied or if back charges are levied prompting a subcontractor to enforce its rights, execute a claim, or proceed to litigation.