1. BACK PAIN Disc herniation

2. History Primitive cultures attributed it to the work of demons Ancient Greeks recognized the symptoms as a disease Goldthwait in 1911 attributed back pain to posterior dislacement of the disc (disc tumor) Barr in 1932 attributed sciatica to herniated lumbar disc –suggested surgical treatment

3. epidemiology Hult estimates 80% of people are affected by this symptom at some time in their lives (Acta Orth Scand 1954) Dillane,fry and Kalton reported 79% of men 89% of women the specific cause was unknown( BMJ 1966)

4. epidemiology Saal and Saal noted: 80% of those reporting chronic back pain did not report limitation of activity Females more frequently than males No racial differences

5. epidemiology Carey et al 1992: incidence 3.9% chronic low back pain in 4437 North Carolinians 34% of those permanently disabled

6. Cost Lost work time Compensation (~~2 billion $/year in USA) Treatment (1/3 total cost)

7. Factors affecting….. Jobs requiring heavy and repetitive lifting,use of machine tools,operation of motor vehicles Cigarette smokers Anxiety, depression, stressful occupations Number of pregnancies Frymoyer et al JBJS 1983

8. …. Scoliosis Jackson,Simmons Spine 1983 Patients taller than 181cm Gyntelberg F Dan Med Bull 1974 Obesity Deyo,Bass Spine 1989

9. Disc anatomy

10. Nucleus pulposus Loose,nonoriented,collagen fibril framework supporting a network of cells resembling fibrocytes and chondrocytes Gelatinous matrix of various glucosaminoglycans,water and salts

11. Annulus fibrosus Concentric rings of fibrocartilaginous tissue Rings attach to each other with additional diagonal fibers Rings are thicker anteriorly

12. Neural elements Neural fibers exist in the outer rings of the annulus They are branches of sinu vertebral nerve lying dorsally (small filamentous nerve originates from ventral ramus) Bogduk N : Spine 7:319 1982

13. Natural history Stage I : Dysfanction 15-45 y old,circumferential & radial tears in disc annulus, localised synovitis of facets Stage II: Instability 35-70y old, internal disc disruption, progressive disc resorption, facet degenaration,sublaxation, joint erosion

16. Natural history Stage III : Stabilisation Osteophytes, stenosis, spondylosis Kirkaldy-Willis Spine 4:102-109, 1979 Disc disease :one of recurrent episodes of pain followed by periods of significant or complete relief

19. Simple compression of nerve root creates sensory & motor symptoms but no pain Smyth MJ, Wright V JBJS 40A:1401-1418 1958

21. Chronic irritation by compression tends to be painful Smyth,Wright JBJS 1958 Howe,Laser,Calvin Pain 3:25- 41,1977

24. Consequences of pressure Alteration in intraneural blood flow Problems with axoplasmic transport Inflamation, edema, demyelination Nobuhiro H,Hwan-Mo L,Weinstain JN textbook of spinal disorders 1996 Rydevik BL,Brown MD,Lundberg G : Spine 9:7-15 1984

25. Kawakami et al Journal of Orthopaedic Research vol 18-2, 2000 Mechanical constriction leads to demyelination,alters pain related behavior Nucleus pulpusus:mechanical hyperalgia 4-0 silk loop: no hyperalgia Silk loop +nucleus pulpusus: thermal hypralgesia

26. Park JB,Chang H,Kim YS Spine 1;28(1):100 2003 Immune reaction Increase interleukin 12,T-helper Type I, interferone-gamma(INF-gamma),Th2(IL-4)

27. Kawakami et al Spine 21(18):2101-2107 1996 pH Interleukin I Phospholipase A2 Nitric Oxide

29. THANK YOU