1. BACK PAIN - CHRONIC ISSUES
David Borenstein, MD
Clinical Professor of Medicine
Arthritis and Rheumatism Associates
The George Washington University Medical Center
Washington, DC

2. 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?)

3. 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

4. WHAT IS CHRONIC LOW BACK PAIN And ITS PREVALENCE?

5. LOW BACK PAIN - DEFINITION
Pain that occurs in an area with boundaries between the lowest rib and the crease of the buttocks

6. Chronic Low Back Pain Duration greater than 3 months
Pain that persists longer than the expected time period for healing

7. 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 > 1 year 8.8% of claims %-84.7% of annual costs
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CDC. MMWR 2001;50:
Hashemi L et al: J Occup Environ Med 1998;40:

8. 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
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van den Hoogen et al: Ann Rheum Dis 1998;57:13-19

9. Low Back Pain - Disorders
Mechanical Referred
Rheumatologic Hematologic
Infectious Neurologic
Neoplastic Psychiatric
Endocrinologic Miscellaneous
(N > 60)
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Borenstein D, Wiesel S, Boden S: Low Back Pain: Medical Diagnosis and Comprehensive Management. 1995

10. 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

11. 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

12. 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

13. Diagnostic Evaluation
Diagnosis of low back pain is unspecified in 80% of patients
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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:
White AA, Gordon S. Symposium on Idiopathic Low Back Pain. Mosby Co. 1982

14. 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
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Abraham I, Killackey-Jones B: Arch Intern Med 2002;162:

15. 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
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Deyo RA: Arch Intern Med 162: , 2002

16. 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

17. Chronic Back Pain - Outcome Measures
Back specific function
Pain
Patient global satisfaction

18. Back Pain - Outcome Measures
Back Specific Function
Roland Morris Disability Questionnaire
Oswestry Disability Index

19. 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
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Roland M, Morris R: Spine 1983;8:

20. 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
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Fairbank J, Pynsent P: Spine 2000; 25:

21. Back Pain - Outcome Measures
Pain Measurement
SF-36 pain scale
Visual analog scale (VAS)
Brief Pain Inventory (BPI)
Treatment Outcomes in Pain Survey (TOPS)

22. Back Pain - Outcome Measures
Global Satisfaction
Extremely, very, somewhat satisfied
Mixed
Somewhat, very, extremely dissatisfied

23. Back Pain - Outcome Measures (Optional)
General health status
SF-36
Depression
Beck Depression scale

24. 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

25. Chronic Low Back Pain Therapy - Multimodality
Back exercises - flexion and/or extension
Aerobic exercise
Medications
Counterirritant topical therapies
Stress management

26. Chronic Low Back Pain - Medications
NSAIDs
Muscle relaxants
Analgesics
Antidepressants
Anticonvulsants
Alpha-2 adrenergic agonists
Miscellaneous
NONE ARE INDICATED FOR CHRONIC LOW BACK PAIN!

27. 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:

28. Chronic Low Back Pain - Medications - Muscle Relaxants
Cyclobenzaprine
Orphenadrine
Metaxolone
Chlorzoxazone
Methocarbamol

29. Chronic Low Back Pain - Medications - Analgesics
Nonnarcotic
Acetaminophen
Tramadol
Narcotic
Short acting
Long acting

30. 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

31. Case Study - Chronic Somatic Pain - Mild to Moderate
67 year old person - facet arthritis
Treatment regimen
Rofecoxib mg QD
Cyclobenzaprine 10 mg QHS

32. 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

33. 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

34. 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