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BACK PAIN - CHRONIC ISSUES. David Borenstein, MD Clinical Professor of Medicine Arthritis and Rheumatism Associates The George Washington University Medical Center Washington, DC. Chronic Low Back Pain. Issues for Discussion
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BACK PAIN - CHRONIC ISSUES David Borenstein, MD Clinical Professor of Medicine Arthritis and Rheumatism Associates The George Washington University Medical Center Washington, DC
Chronic Low Back Pain Issues for Discussion 1. Define the forms of chronic low back pain and its prevalence (Is it frequent and important enough to study?) 2. Will patient selection including etiology and severity influence the performance of drugs in development? (Is it possible to identify and separate the individuals with back pain?) 3. Which are the appropriate outcome measures? (Can improvements in back pain related to therapy be determined?)
Chronic Low Back Pain Issues for Discussion 4. Will a general indication be useful for different labeling claims? (somatic v. neuropathic v. chronic headache) 5. Chronic low back pain - serve as a measure of efficacy for a general chronic pain indication or specific indication for chronic low back pain alone
LOW BACK PAIN - DEFINITION Pain that occurs in an area with boundaries between the lowest rib and the crease of the buttocks
Chronic Low Back Pain Duration greater than 3 months Pain that persists longer than the expected time period for healing
Epidemiology of Low Back Pain 20% of the US population develops back pain yearly Back pain -second most common cause of disability in the US (leading cause among men) accounting for 16.5% of the total disabilities in > 18 yo in 1999 Workers’ compensation 1986-1996 - > 1 year 8.8% of claims - 64.9%-84.7% of annual costs ___________________________________ CDC. MMWR 2001;50:120-125 Hashemi L et al: J Occup Environ Med 1998;40:1110-1119
Natural History of Low Back Pain 443 LBP subjects postal questionnaire 12 months 15 general practices Amsterdam, Netherlands 269 completed survey - less pain answered less often 7 weeks-median time to recover At 12 weeks-35%, 52 weeks-10% had LBP 75% had 1 or more relapses during study Pain and disability was less during relapses Time to relapse-median 7 weeks, duration-median 6 weeks __________________________________________ van den Hoogen et al: Ann Rheum Dis 1998;57:13-19
Low Back Pain - Disorders Mechanical Referred Rheumatologic Hematologic Infectious Neurologic Neoplastic Psychiatric Endocrinologic Miscellaneous (N > 60) _____________________________________ Borenstein D, Wiesel S, Boden S: Low Back Pain: Medical Diagnosis and Comprehensive Management. 1995
Low Back Pain - Disorders Mechanical - 85% of all low back pain Muscle, ligament, tendon strain Discogenic disorders including herniated disc Apophyseal joint arthritis Spinal stenosis Spondylolysis, spondylolisthesis Scoliosis
Sources of Low Back Pain Superficial somatic - skin Deep somatic - muscle, joint, tendon, bursa, fascia Radicular - nerve root Visceral referred - sympathetic afferents Neurogenic - mixed motor sensory nerves Psychogenic - cerebral cortex
Pain Intensity Minimal - mentioned in passing, normal function Mild - component of symptoms, mild dysfunction Moderate - major component of symptoms, alters function Severe - the disease symptom, incapacitating function
Diagnostic Evaluation Diagnosis of low back pain is unspecified in 80% of patients _________________________________________ Dillane JB et al: Acute back syndrome: a study from general practice. BMJ. 1966;2:82-84 Rowe ML: Low back pain in industry: a position paper. J Occup Med 1969;11:161-169 White AA, Gordon S. Symposium on Idiopathic Low Back Pain. Mosby Co. 1982
LOW BACK PAIN - DIAGNOSIS Specific diagnosis is possible Differentiation of muscle, joint, ligamentous structures Mechanical versus systemic disorders is possible Categorize by clinical symptoms Subtyping will improve therapy _____________________________________ Abraham I, Killackey-Jones B: Arch Intern Med 2002;162:1442-1444
LOW BACK PAIN - DIAGNOSIS Specific diagnosis is impossible Anatomic abnormalities in asymptomatic individuals Overutilization of imaging techniques Inconsistency of physical findings Non-specific therapy is effective ____________________________________ Deyo RA: Arch Intern Med 162:1444-1446, 2002
LOW BACK PAIN - DIAGNOSIS Somatic v. neuropathic v. radicular pains can be differentiated Specific pain generators (individual joint or muscle) are difficult to identify but localization is not essential for effective therapy
Chronic Back Pain - Outcome Measures Back specific function Pain Patient global satisfaction
Back Pain - Outcome Measures Back Specific Function Roland Morris Disability Questionnaire Oswestry Disability Index
Back Pain - Outcome Measures Roland-Morris Disability Questionnaire - function assessment 24 items from the Sickness Impact Profile Functions affected by back pain that day Scores added ( 0-no disability to 24 -maximum disability) Validated and reproducible instrument ___________________________________ Roland M, Morris R: Spine 1983;8:141-144
Back Pain - Outcome Measures Oswestry Disability Index - pain and function assessment 10 sections on various functions with 6 levels of assessment Physical and social functions that day Scores added (0-no disability to 100-maximum disability) Validated and reproducible instrument _____________________________________ Fairbank J, Pynsent P: Spine 2000; 25:2940-2953
Back Pain - Outcome Measures Pain Measurement SF-36 pain scale Visual analog scale (VAS) Brief Pain Inventory (BPI) Treatment Outcomes in Pain Survey (TOPS)
Back Pain - Outcome Measures Global Satisfaction Extremely, very, somewhat satisfied Mixed Somewhat, very, extremely dissatisfied
Back Pain - Outcome Measures (Optional) General health status SF-36 Depression Beck Depression scale
Back Pain - Outcome Measures Instruments exist to measure the effect of drug interventions on chronic back pain for: function pain global satisfaction general health status
Chronic Low Back Pain Therapy - Multimodality Back exercises - flexion and/or extension Aerobic exercise Medications Counterirritant topical therapies Stress management
Chronic Low Back Pain - Medications NSAIDs Muscle relaxants Analgesics Antidepressants Anticonvulsants Alpha-2 adrenergic agonists Miscellaneous NONE ARE INDICATED FOR CHRONIC LOW BACK PAIN!
Chronic Low Back Pain - Medications - NSAIDS Short half-life acute exacerbations, quick onset Long half-life sustained effect Cox - 2 inhibitors equal efficacy - decreased toxicity van Tulder et al: Spine 2000;25:2501-2513
Chronic Low Back Pain - Medications - Muscle Relaxants Cyclobenzaprine Orphenadrine Metaxolone Chlorzoxazone Methocarbamol
Chronic Low Back Pain - Medications - Analgesics Nonnarcotic Acetaminophen Tramadol Narcotic Short acting Long acting
Case Study - Chronic Somatic Pain - Mild To Moderate 52 year old person - work-related myofascial injury Treatment regimen Change of NSAID - diclofenac 100mg QD Maintain methocarbamol 750mg BID Diclofenac 50mg prn acute exacerbations maintain exercises program
Case Study - Chronic Somatic Pain - Mild to Moderate 67 year old person - facet arthritis Treatment regimen Rofecoxib 25mg QD Cyclobenzaprine 10 mg QHS
Case Study - Chronic Somatic Pain - Moderate to Severe 72 year old person - s/p laminectomy with fractured screw Treatment regimen Celecoxib 200mg BID Nortriptyline 50mg QHS Fentanyl patch 50 mcg Hydrocodone 5 mg prn
Case Study - Chronic Neuropathic Pain - Moderate to Severe 42 year old person - traumatic neuropathy - sciatic nerve Treatment regimen Ketoprofen - long acting - 200mg QD Gabapentin - 100mg TID Oxycodone - long acting - 40mg TID Hydrocodone - 7.5mg PRN
Chronic Low Back Pain - Summary Model for chronic pain Outcome tools are available Somatic pain is identifiable Degree of pain - effect on study design mild to moderate - single drug v. placebo (active comparator) moderate to severe - stable multidrug regimen - flare with withdrawal