Lower Back Pain Therapy

Christine Mai, MD

Department of Anesthesiology

Boston University Medical Center

Lower Back Pain

One of the most common problem seen by pain specialists

Second to headaches as cause of chronic pain Major cause of work disability worldwide Multifactorial Causes: congenital, traumatic,

degenerative, myofascial syndrome, inflammatory, infectious, metabolic, psychologic, cancerous, or referred pain from retroperitoneal disease processes

Anatomy of Lumbar Spine Anterior components:

Vertebral bodies Intervertebral disks Anterior/Posterior longitudinal

ligaments Posterior components:

2 pedicles 2 transverse processes 2 lamina Spinous process

Innervation: Sinuvertebral branches arises before

spinal nerve divides into anterior and posterior rami, innervates posterior longitudinal ligament, posterior annulus fibrosis, periosteum, dura and epidural vessels

Posterior Rami innervates paraspinal structures

Lumbar Facet Joint Paired facet joints connect vertebrae

in the spine Important for both range of motion

and stability Painful when become arthritic Facet arthropathy can further cause

back spasm and referred pain frequently indistinguishable from sciatica or discogenic radicular pain

Each facet joint is innervated by medial branches of posterior primary rami, above and below the joint

Medial branch crosses upper border of the lower transverse process in groove between root of transverse process and superior articular process

Lumbar Medial Branch Facet Injection Performed under fluoroscopy with

patient in prone position Views: AP and 30o oblique (Scotty

dog view) Insert a 22 gauge spinal needle 5-

6cm lateral to spinous process, directed medially to upper border of root of transverse process

Insert at three levels (ie. L3-4, L4-5, L5-S1)

Medication: 40-80mg Triamcinolone or Methylprednisone and local anesthetic or perservative free NS

Radiofrequency Themocoagulation (RFTC)

Ablates nerve branches utilizing heat current flows from active electrode incorporated in special needle

Temperature 60-90oC for 1-3mins to ablate nerve without excessive tissue damage

Performed under fluoroscopy-important to be exactly within “eye of Scottie dog”

Electrical stimulation (2 Hz for motor response, 50 Hz for sensory response) via electrode and impedence measure help confirm correct position

Prolongs pain relief for 3-12 months Utilized for medial branch facet rhizotomy, trigeminal

rhizotomy, dorsal root rhizotomy, lumbar sympathetomy

Lumbar Radiculopathy Lower back pain radiating down

lower extremities Sensations of pain, paresthesia,

numbness Associated with herniated disks,

DJD, nerve impingement Sciatica-compression of lower

nerve roots producing pain along sciatic nerve

Paracentral compression of cauda equina in dural sac can cause bilateral LLE pain, urinary retension, fecal incontinence

Inflammation results from nerve root compression

Epidural Steroid Injections

Effective pain relief for radiculopathy Relieves inflammation, edema and irritation by

reducing swelling of nerve root, blocking c-fibers, stabilize nerve membranes, and decrease ectopic discharge from inflamed tissue

Inflammatory mediators leak into epidural space rather than subarachnoid space

Translaminar Lumbar Epidural Steroid Injection

Performed under fluroscopic guidance Views: AP and Lateral Maybe be left or right differentiated depending on patient’s pain location 20 gauge Touhy needle Loss of resistance to air/saline technique Medications: Triamcinolone 40-80mg or Methylprednisolone 40-80mg injected with local anesthetic or

with perservative free NS Local anesthetic provides immediate pain relief until steroid inflammatory response takes place in 12-48hr

Transforaminal Lumbar Epidural Steroid Injection

Performed when there is correlating lesion on MRI with radiculopathy Alternative approach to epidural space when translaminar ESI fails to give relief 22 G spinal needle directed under fluoroscopy into foramen of affect nerve root

and contrast is injected to confirm entry into epidural space prior to steroid injection

Less volume of steroid/local anesthetic needed

Risks of ESI

Bleeding Infection Localized tenderness Post-dural puncture headache Paresthesia Anxiety-related sx: lightheadedness, nausea

Selective Nerve Root Block

Performed when there is correlating lesion on MRI with radiculopathy Used interchangeably with transforaminal epidural steroid injection 22 gauge spinal needle inserted under fluoroscopy lateral to spinous

process, directed medially to lower border of root of transverse process Contrast is injected to confirm injection proximal to nerve root

Lumbar Facet Injection

Lumbar ESI

Selective Nerve Root Block