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 56cm lateral to spinous process, directed medially to upper border of root of transverse process Insert at three levels (ie. L3-4, L45, 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