BACK PAIN - CHRONIC ISSUES David Borenstein, MD Clinical Professor of Medicine Arthritis and...
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Transcript of BACK PAIN - CHRONIC ISSUES David Borenstein, MD Clinical Professor of Medicine Arthritis and...
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 PainIssues 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
WHAT IS CHRONIC LOW BACK PAIN
AndITS PREVALENCE?
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 Pain443 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 MeasurementSF-36 pain scale
Visual analog scale (VAS)
Brief Pain Inventory (BPI)
Treatment Outcomes in Pain Survey (TOPS)
Back Pain - Outcome Measures
Global SatisfactionExtremely, 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