Intervertebral Discs Structure, Movement, and Herniation Mike Pichette, Casey Moran, Kristen Palmer

Disc Layers & Tissue Structure  Annulus Fibrosis Concentric fibrocartilage rings Fibers oblique and at right angles Peripheral vascularity  Nucleus Pulposus Gelatinous central core Mostly water, the rest is collagen Avascular  Symphysis Joints  Thickness varies  No disc C1 and C2, L5/S1 most inferior

Age Related Changes  AF thickens and ↑ load bearing  NP dehydrates, cellular changes ↓ Elastin and proteoglycans ↑ Collagen  Disc replacement Plastic and cobalt-chrome Viscoelastic polymer and beaded titanium

Vertebral Disc Herniation  Herniation: Nucleus Pulposus moves out of place and breaks open, pressing into nerve root  Lumbar region most common Sciatica (pain from lower back into leg)  Symptoms: Dull or sharp pain, muscle spasms or cramping, leg weakness, numbness, tingling  Increased risk: Aging, lifestyle choices, poor posture, incorrect/repetitive lifting Image:

Stages of Disc Herniation 1. Disc Degeneration: Aging causes NP to weaken 2. Prolapse: Disc changed position leads to impingement 3. Extrusion: Nucleus Pulposus breaks through annulus fibrosus (no herniation) 4. Sequestered Disc: Nucleus Pulposus breaks through the annulus fibrosus (HNP)

Miyakoshi et al. Case Study  53-year-old Japanese male  Symptoms: sudden onset of incomplete paraplegia after lifting a heavy object Motor strength: 0/5 R LE and 0-2/5 L LE Sensory loss below level of umbilicus Urinary incontinence  MRI results: posterior epidural mass compressing the spinal cord at T9-T10 level

Case Study Cont.  Surgical procedures: laminectomy at T9-T10, facetectomy, removal of mass lesion, and posterior instrumented fusion  Intra-operative diagnosis: posteriorly migrated thoracic disc herniation  Prognosis: resumed to walking without a cane by 4 weeks post surgery  Discussion: Only 0.15% to 4% of all symptomatic disc herniations occur in thoracic spine Only 5 cases (in 2013) of posteriorly migrated thoracic disc herniation had been reported Should be considered for differential diagnoses

References Colorado Comprehensive Spine Institute. (n.d.). Retrieved June 6, 2015, from Kim, I. S., et al. (2008). Posterior epidural migration of thoracic disc fragment. Journal of Korean Neurosurgical Society, 43(5): doi: /jkns Marieb, E. N., & Hoehn, K. ( 2013). Human anatomy and physiology (9 th ed). Glenview, IL: Pearson Education, Inc. Miyakoshi, N. et al. (2013). Posteriorly migrated thoracic disc herniation: a case report. Journal of Medical Case Reports, 7: 41. doi: / Moore, K. L., Agur, A. M. R., & Dalley, A. F. (2011). Essential clinical anatomy (4th ed.). Baltimore, MD: Lippincott Williams & Wilkins.