Conservative and Surgical Approaches for Acute and

Chronic Back Pain

Donald S. Corenman, M.D., D.C.Steadman Hawkins Clinic

Spinal Function• Provide enough flexibility to

allow positioning of head and trunk in space for ADLs

• Must have strong resistance to motion excess that could damage cord and nerves

• Ligament and disc- passive resistors and dampeners of motion

• Tendons and muscles- active stabilizers and movers

Circulatory Changes in the Disc• Notochord turns into

annulus of disc• Vascularity of disc

diminishes – arterioles lose their access to the disc as the endplate matures

• Disc becomes more avascular over time (largest mass of avascular tissue in the body)

• Imbibition- only nutrient exchange after this point

Discal Changes with Aging• After skeletal maturity, type I

collagen increases and discal water decreases (stiffens disc)

• O2 concentration is 20-30X greater at periphery of disc than at center (imbibition)

• Chondrocyte cells decrease and necrotic cells can be identified

• Entire disc appears disorganized

• Large voids appear (vacuum sign)

• Peripherally- osteophyte formation (enthesopathy)

Mechanical Stress with Flexion on Lumbar Discs

• Flexion loads the anterior column

• Due to distance from fulcrum (femur), anterior load increases logarithmically

• Opposition by erector spinae and multifidi with poor lever arm distance from load creates mechanical disadvantage

Annular Anatomy• Annular fibers are in lamina

(layers)• Approximately 60 layers from

outside to innermost• When nucleus loses hydration

(aging)- pressure drops and more stress on annulus

• Rotation stretches 50% of fibers (and relaxes the other 50%)

• Disc loses 50% of strength by rotation

• Flexion loads disc and stretches fibers (possibly to failure)

Annular/Discal Biomechanics

• Normal disc will resist displacement over time

• Degenerative disc has less resistance to displacement- increased possibility to move into zone of injury

• Flexion stretches post annulus- greater chance of tearing posterior fibers

The Devil’s in the Details• Flexion causes

posterior annular fibers to come under tension

• Rotation causes 50% of the annular fibers to have load reduction

• Loading the spine- especially with a load further away from the body can cause annular tears

Annular Tears• Tears of the posterior

annulus allows nucleus to come into contact with posterior 1/3 nociceptors- sensitizing then

• Attempts at repair of the tears of the annulus allows neovascularization with resultant nociceptor ingrowth into damaged areas

• Tears also allow aberrant motion of the segment, further stressing the nociceptors

Pathophysiology of the Facets

• Articular cartilage is 70% water- responsible for cushioning bone from impacts

• When the disc degenerates, increasing pressure and aberrant motion fibrillates cartilage. Capsule pulls away from insertion

• Enthesopathy occurs causing spur formation• Capsular rents occur allowing outpouching

of synovial lining• Ganglion cyst formation occurs• Erosion of the facets from shear forces

causes degenerative spondylolysthesis

So- where does the pain come from????????

Smyth and Wright, JBJS(B) 40ASmyth and Wright, JBJS(B) 40Aintraoperative connection of nylon threads to intraoperative connection of nylon threads to

spinal structures with post-operative stimulation spinal structures with post-operative stimulation • Tension on normal nerve root produced no Tension on normal nerve root produced no

sciaticasciatica

• Interspinous ligament and Ligamentum Interspinous ligament and Ligamentum Flavum produced no painFlavum produced no pain

• Dura Mater was generally insensitiveDura Mater was generally insensitive

• The greater the pressure to a compromised The greater the pressure to a compromised nerve root, the greater the length of radiated nerve root, the greater the length of radiated pain (buttocks- thigh- calf- foot)pain (buttocks- thigh- calf- foot)

Kuslich, OCNA April 91Kuslich, OCNA April 91pain response to tissue stimulation under local pain response to tissue stimulation under local

anesthesiaanesthesia• Capsule- rarely generated any pain upon Capsule- rarely generated any pain upon

stimulation.stimulation.

• Muscle could produce sharp pain with Muscle could produce sharp pain with forceful stretching “but only rarely forceful stretching “but only rarely simulated the deep dull ache of lumbago”simulated the deep dull ache of lumbago”

• ““Normal Nerve Root”- completely Normal Nerve Root”- completely insensitive to pain, forceful prolonged insensitive to pain, forceful prolonged retraction caused mild paresthesias onlyretraction caused mild paresthesias only

Kuslich, OCNA April 91Kuslich, OCNA April 91pain response to tissue stimulation under local pain response to tissue stimulation under local

anesthesiaanesthesia

• Sciatica- only by stimulation of swollen or Sciatica- only by stimulation of swollen or stretched nerve rootsstretched nerve roots

• Back Pain- stimulation of outer layer of Back Pain- stimulation of outer layer of posterior annulus and PLLposterior annulus and PLL

• Buttocks Pain- simultaneous stimulation of Buttocks Pain- simultaneous stimulation of annulus and nerve rootannulus and nerve root

Posterior Annular Nociceptors

Nerve pain receptors stimulated by presence of chemicals or tissue damage (Unmyelinated “C” fibers -slow conducting)

Sensitization: lower threshold or enhanced responses to suprathreshold stimuli

Hyperalgesia : nociceptors responding to stimuli release neuromodulators that decrease threshold of neighboring nociceptorsSensitization can cause cortically mediated lowered pain threshold or enhanced pain response

Nociceptor Nerve Injury• Amplification: one root can

induce activity in a neighboring root called an artificial synapse “crosstalk”

• Conduction Block: Compression causes demyelination causing a block of the nerve

• Ectopic Impulses: Lesions of peripheral nerves, DRG or roots can cause firing of a nerve identical to a neuroma

Arachidonic Acid• Found in all cell membranes• Broken down into 2 pathways

by mediators• Cyclooxygenase causes

prostaglandin formation which is blocked by NSAIDs

• Lipooxygenase creates Leukotrienes- not blocked by NSAIDs

• Leukotrienes cause chemotaxis of PMNs, degranulation and hypersensitivity of nociceptors

Why do we need pain receptors in the first place?

• Nociceptors are important to signal damaging motion to the disc and bone of the vertebra

• Without this feedback of noxious stimulus, a Charcot spine develops

• Destruction occurs in any joint that has no feedback mechanism by overload and motion beyond tissue tolerance

Sources of Lower Back Pain

• Annular Tears• Isolated Disc Resorption• Stenosis- central or

foramenal• Instablilty• HNP (occasionally)• Spondylolysthesis• Sacroiliac Joints• Facets• Referral

General Indications for Surgery

• Progressive neurological weakness

• Bowel and bladder involvement

• Symptoms that are intolerable or have failed conservative therapies

Physical Therapy to Modify Structure and Behavior

• Education- Eliminate motions that put disc in jeopardy

• Ergonomics- Change workplace and recreational equipment

• Activity avoidance and modification

• Stretch structures that put strain on damaged area

• Strengthen muscles that protect the area

• Change sagittal alignment for stenotic patients

Oral Chemical Modulation of Pain

• Narcotics• Nsaids• Muscle “relaxants”• Membrane stabilizers• SSRIs• Steroids• Acetominophen

Epidural and Facet Steroids

• Steroids reduce nociceptor inflammation

• Reduce degranulation of PMNs

• Make root membranes less permeable to discal toxins

Percutaneous Spinal Treatments

• Rhizotomy• IDETT• Percutaneous

nucleoplasty

Surgical Treatment- Decompression

• Laminectomy for spinal stenosis

• Microdiscetomy for HNP

• Foramenotomy for root entrapment

Surgical Treatment- Fusion

• Only for 1-2 degenerative discs for LBP

• Recovery- 6mo• Success rate- 85%• Pain relief- 65%• Worry about discs

above and below

How to Treat Low Back Pain in 15 Seconds

• Try to treat all LBP conservatively if no contraindications

• Must have accurate diagnosis• Physical therapist must be

trained in spinal rehab. and know diagnosis

• Use oral medications• Diagnostic and therapeutic

blocks• Must motivate and educate

patient!!!!!!• Surgery if necessary with an

informed patient

“The lower back is at the crossroads where the

psyche meets the soma”Voltaire

Thank You