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Axial Low Back Pain
Alex Ching
Low Back Pain

Low Back Pain
• Common
– Prevalence – 66% lifetime
– Incidence – 20% per year
– #2 cause for physician visit
Structural Causes of LBP
• Instability
– Spondylolisthesis
– Scoliosis
• Deformity
• Tumor
• Infection
• Trauma
Non-Spine Causes of LBP
Etiology
• Facets
• Intervertebral disc
– Nucleus
– Annulus- thought to be primary pain generator
– Surrounding structures
• Muscle and ligaments
Radiographic Workup
• Plain radiographs
– Fever
– Unexplained weight loss
– History of cancer
– Neurologic deficits
– Alcohol or injection-drug abuse
– Age of more than 50 years
– Trauma
– Failure to improve within six weeks
CT
• Best visualization of bony anatomy
– Tumor, infection
• Excellent imaging of facet joints
MRI
• Excellent for evaluation of soft tissues
– Disk dehydration
– End plate changes
CT and MRI
Discogenic Low Back Pain
• DDD does not equal LBP
• Normal aging process includes
– Dehydration of nucleus
– Collapse of the disc space
– Sclerosis of the endplates
Natural History
• Generally benign
– 90% resolution within 2 weeks in one study
– Bigger studies
• 1/3 improved in 2 weeks
• 2/3 improved in 7 weeks
• 40% recurrence within 6 months
• Smoking (and number of cigarettes per day) correlated with both LBP and severity of LBP

Work
• Leading cause of disability in the <45 y.o. population
• Time out of work has prognostic significance
– Out 6 months, 50% return to work
– Out 1 year, 25% return to work
– Out more than 2 years, <5%
• Legal involvement related to worse surgical outcomes
Non-Operative Treatment
• Bedrest
– Unproven to help or hurt
– 2 days at most
• Orthoses
– Not proven to change natural history
– Tend to be discouraged
• Medications
– NSAIDs
– Minimize narcotics and steroids
– Muscle relaxants have documented benefit
– Antidepressants
Non-Operative Treatment
• Physical Therapy
– Better than medical management alone
– Flexion and extension exercises with dynamic stabilization
– No one program shown most effective
– Massage shown to be effective
– Traction unproven
• Manipulation
– 15% of the population seeks chiropracticcare each year
– Equivalent to therapy for acute pain
Non-Operative Treatment
• Selective Injections
• Diagnostic and therapeutic
– Epidural
– SI joint
– Facet
– Dorsal Rhizotomy
• Intradiscal Electrothermal Therapy
– Discectomy approach, thermal heating of nucleus
– Unclear efficacy

The Controversy
What is the role of surgery for low back pain?
Which is the optimal surgery?
Surgical Options
• Posterolateral fusion
• Posterior interbody fusion
• Anterior interbody fusion
• Total disk arthroplasty
Surgical Results
“Glaring deficiencies were noted in the spinal literature … concerning lumbar fusion for degenerative disc disease.”

Posterolateral Fusion
• Oldest track record
• Simplest procedure
• Hall et al., 90% fusion rate, 73% clinical success
• Fusion rate higher with instrumentation than without
Interbody Fusion
• Addresses “pain generator” of disc
• Biomechanically superior
• Technically more demanding
• 72 to 93% success rates reported posteriorly
• 68% success rate reported anteriorly
• 77% success rate with circumferential fusion
• Results significantly worse for greater than one level
Swedish Lumbar Spine Study Group
• 294 patients randomized to four treatment groups from 1992-1998
– Non-op
– Non-instrumented posterolateral
– Instrumented posterolateral
– Interbody plus instrumented posterolateral
• Minimum 2 year follow-up
• 122 single level and 89 2 level fusions
Results
• Avg 9.5 hospital days for surgical groups
• Surgery did significantly better in back pain, disability scores, self-rated improvement, and return to work rates
– Still only 63% rate better or much better, and only 36% return to work
• No difference between surgical groups in terms of function or pain, but higher fusion rate as increased surgery (91% in interbody group)
UK Study
• 349 patients with 12 months of LBP, no prior surgery across 15 hospitals randomized to “surgical stabilization” or rehabilitation, 24 month follow-up
– No standardization of surgical treatment
• Slight improvement in Oswestry disability score in surgical group
Norwegian Study
• 64 patients, low back pain >1 year randomized to instrumented single level posterolateral fusion versus rehabilitation with 1 year follow-up
• Slightly more improvement in Oswestry for surgical group, no difference in pain, analgesic use, satisfaction, or return to work
• Success rate of 70% with surgery, 76% without

Total Disk Arthroplasty
• Theoretical advantages:
– Motion preservation
– More physiologic
– Avoids adjacent disease
• Concerns
– Does not address facets
– Does not address canal
– Wear/failure
– Dislocation
– Revision
Total Disc Results
• Charite
– Similar results in terms of pain relief between BAK cages and Charite
• ProDisc
– 75% good to excellent results at 8.7 years
– Reported results appear to be similar to A/P fusion