INTERVERTEBRAL DISC ANATOMY AND PIVD OF LUMBAR SPINE AND ITS MANAGEMENT

a brief overview on the anatomy of intervertebral disc, PIVD of lumbar spine and its management.

1. INTRODUCTION TO INTERVERTEBRAL DISC ANATOMY, PIVD (LUMBAR) AND ITS MANAGEMENT Presented by: Dr. Ben Tungoe PG, M.S(Orthopedics ) Central Institute of Orthopedics VMMC & Safdarjung Hospital, New Delhi

2. ANATOMY OF INTERVERTEBRAL DISC fibro cartilaginous structure. contributes 25% of the height of spinal column. function of shock absorption, transmitting compressive loads between vertebral bodies. Composed of the central nucleus pulposus (NP), the peripheral annulus fibrosus (AF) and the end plates(EP). The end plate is a bilayer of cartilage that separate the IVD from the vertebral body(VB) and serves as growth plate for the VB.

3. NUCLEUS PULPOSUS: Highly hydrated structure, approx. 88% water Hydrophilic matrix: composed of proteoglycans(PG) interspersed within an irregular mesh of type-2 collagen and elastin fibers. The proteoglycans have a large number of anionic glycosaminoglycans (GAG) side chains i.e chondroitin sulfate and keratan sulfate which allows the nucleus to imbibe water. Low collagen and high PG ratio. Characterised by compressibility.

4. ANNULUS FIBROSUS -composed of concentric rings/lamellae of highly organised T ype-1 collagen fibres which are interwoven. -high collagen and low PG ratio -the fibres are oriented 60 degree to the vertical axis of spine and parallel within each lamella and perpendicular between adjacent lamallae . - lamallae are thicker anteriorly and laterally and thinner posteriorly -AF functions to contain the NP and maintain its pressurization under compressive loads. -characterized by extensibility and tensile strength

5. BLOOD AND NERVE SUPPLY Blood Supply    the disk is avascular with capillaries terminating at the end plates nutrition reaches nucleus pulposus through diffusion through pores in the endplates  annulus is not porous enough to allow diffusion  Innervation the dorsal root ganglion gives rise to the sinuvertebral nerve which innervates the superficial fibers of annulus no nerve fibers extend beyond the superficial fibers neuropeptides thought to participate in sensory transmission include substance P calcitonin VIP CPON

6. Distribution of load in the inter-vertebral disc.  ( A) In the normal, healthy disc, the nucleus distributes the load equally throughout the annulus.  (B) As the disc undergoes degeneration, the nucleus loses some of its cushioning ability and transmits the load unequally to the annulus.  (C) In the severely degenerated disc, the nucleus has lost all of its ability to cushion the load, which can lead to disc herniation.

7. Disc B iomechanics Disc viscoelastic characteristics demonstrates creep which allows for deformity over time demonstrates hysteresis which allows for energy absorption with repetitive axial compression this property decreases with time Stresses annulus fibrosus highest tensile stresses nucleus pulposus highest compressive stress Intra- discal pressure is position dependent pressure is lowest when lying supine pressure is intermediate when standing pressure is highest when sitting and flexed forward with weights in the hands when carrying weight, the closer the object is to the body the lower the pressure Stability following subtotal discectomy, extension is most stable loading mode

8. Pathoanatomy Disc Herniation herniated disks are associated with a spontaneous increase in the production of  osteoprotegrin (OPG) interleukin-1 beta receptor activator of nuclear factor- kB ligand (RANKL) parathyroid hormone (PTH ) Disc aging leads to an overall loss of water content and conversion to fibrocartilage . Specifically there is decrease in  nutritional transport  water content absolute number of viable cells proteoglycans pH increase in an increase keratin sulfate to chondroitin sulfate ratio  lactate degradative enzyme activity density of fibroblast-like cells  fibroblast-like cells reside in the annulus fibrosus only no change in absolute quantity of collagen

9. SPECTRUM OF DEGENERATIVE JOINT DISEASES OF SPINE Internal disc disruption Disc herniation Degenerative spondylolisthesis Spinal stenosis Adult spinal deformities

10. Spectrum of changes( Kirkaldy Willis Concept) Internal disc disruption Disc herniation Intervertebral space decrease Overloading of facet joints, ligamentous instability Instability of motion segment Degenerative spondylolisthesis Attempt to stabilise by formation of osteophytes and ligaments hypertrophy Spinal stenosis Adult spinal deformity

11. Etiology of Intervertebral disc degeneration Repetitive mechanical activities – Frequent bending, twisting, lifting, and other similar activities without breaks and improper stretching Living a sedentary lifestyle – more prone to herniated discs because the muscles that support the back and neck weaken, which increases strain on the spine . Traumatic injury to lumbar discs- commonly occurs when lifting while bent at the waist, rather than lifting with the legs while the back is straight . Obesity – overloading the motion segment . Poor posture – Improper spinal alignment Tobacco abuse – toxins reduces the disc’s ability to absorb nutrients, which results in the weakening of the disc . Mutation- in genes coding for proteins involved in the regulation of the extracellular matrix, such as MMP2 and THBS2,

12. Cellular and Biochemical Changes of the Intervertebral Disc Decrease proteoglycan content. Loss of negative charged proteoglycan side chain. Water loss within the nucleus pulposus . Decrease hydrostatic property. Loss of disc height. Uneven stress distribution on the annulus .

13. Thompson Grading( based on sagittal sections of fresh cadaveric specimen)

14. Pfirmann Grading on MRI

15. MODIFIED PFIRMANN GRADING

16. MODIFIED PFIRMANN GRADING

17. Adam’s classification(based on discography)

18. Concentric tears : circumferential lesions, involves outer layers of the annular wall. Radial tears: characterized by an annular tear which permeates from the deep central part of the disc (nucleus pulposus) and extends outward toward the annulus, in either a transverse or cranial-caudal plane. Transverse tears : also known as “peripheral tears” or “rim lesions,” are horizontal ruptures of fibers , near the insertion in the bony ring apophyses . ANNULAR TEARS

19. L4-L5 CT diskogram demonstrating a large left posterolateral radial anular tear associated with a left foraminal and extraforaminal herniaton

20. Herniated discs in the cranio-caudal ( vertical) direction through a break in one or both of the vertebral body endplates are referred to as “ intravertebral herniations ” (also known as Schmorl’s nodes ). They are often surrounded by reactive bone marrow changes. Nutrient vascular canals may leave scars in the endplates , which are weak spots representing a route for the early formation of intrabody nuclear herniations INTRAVERTEBRAL HERNIATIONS

21. PROLAPSED INTERVERTEBRAL DISC Mostly seen in lumbar region followed by cervical region. Affects young adults 30-40 years who still have relatively maintained disc height. Male:female ratio 3:1 95% involves L4-5 and L5-S1(most common) Herniates through the postero -lateral corner of annulus fibrosus (thin region) Most commont causes: Sudden violent trauma (sports injuries) Less severe trauma in degenerated annulus(lifting, bending, coughing, sneezing etc )

22. Anatomic classification D isc protrusion : the herniated portion of the disc covered with a thin layer of annulus D isc extrusion : disc material herniated through annulus but remains continuous with disc space D isc sequestration: the disc fragment herniates through the annulus and loses contact with the originating disc space

23. Classification based on the location of the disc herniation Posterolateral / paracentral prolapse: Commonest PLL weakest in this area Herniated disc impinges on the traversing nerve roots( e.g the L5 nerve root in L4-5 disc prolapse ) Central prolapse: may present with back pain only or Cauda - equina (severe cases) Foraminal /extra foraminal /far lateral herniation: Less common The herniated disc impinges on the exiting nerve roots (e.g. L4 nerve root in L4-5 level)

24. Clinical features: History History of episode of trauma Radicular pain (buttock and thigh pain, extending below the knee following the distribution of the involved nerve roots) aggravated by flexion, sitting, straining, sneezing, cough decreased by rest, especially in the semi-Fowler position Other symptoms: Weakness Corresponding to level of neurological involvement Paraesthesia in d ermatomal distribution Cauda equina Natural course of symptomatic PIVD is slow resolution of symptoms over 6-8 weeks period in 80% of cases

25. Cauda Equina syndrome Emergency Aggressive evaluation and management Large central herniation M ost consistent symptoms( Tay & Chacha ) saddle anesthesia bilateral ankle areflexia bladder symptoms Other symptoms- numbness and weakness in both legs, rectal pain, numbness in the perineumBowel disturbances

26. Clinical Features- Signs Antalgic gait Affected hip more extended and knee more flexed than normal side Trendelenberg gait (L5 nerve root) List abrupt planar shift Axillary disc –same side Shoulder disc- opposite side Thigh and calf muscle wasting Loss of lumbar lordosis Paraspinal spasm- central furrow sign

27. Provocative tests straight leg raise a tension sign for L5 and S1 nerve root technique can be done sitting or supine reproduces pain and paresthesia in leg at 30-70 degrees hip flexion sensitivity/specificity most important and predictive physical finding for identifying who is a good candidate for surgery contralateral SLR crossed straight leg raise is less sensitive but more specific Lesegue sign SLR aggravated by forced ankle dorsiflexion Bowstring sign SLR aggravated by compression on popliteal fossa Kernig test pain reproduced with neck flexion, hip flexion, and leg extension Naffziger test pain reproduced by coughing, which is instigated by lying patient supine and applying pressure on the neck veins Milgram test pain reproduced with straight leg elevation for 30 seconds in the supine position

28. SLUMP TEST

29. FLIP TEST

30. Clinical features -Neurology L1 L2

31. Clinical Features- Neurology L3

32. Clinical Features- Neurology L4

33. Clinical Features- Neurology L5 Trendelenberg test

34. Clinical Features- Neurology S1

35. Clinical Features- Red Flags Extremes of age (<15yr , >55yr) Neurological deficits Fever Unexplained weight loss(10lb in 6months) Malaise Rest pain/ night pain Significant trauma Drug and alcohol abuse

36. Non Organic Signs Of Waddell Described by Waddel in post op patients Non anatomic tenderness Simulation sign Distraction sign Regional sensory or motor disturbance Overreaction(most sensitive)

37. Differential Diagnosis SPINAL CAUSES: -Trauma -Infection : Osteomyelitis or discitis ( with nerve root pressure) -Inflammation : Arachnoiditis , ankylosing spondylitis -Neoplasm : Benign or malignant with nerve root pressure(multiple myeloma, extradural tumors) EXTRASPINAL CAUSES: Peripheral vascular disease Gynaecological conditions Orthopaedic conditions ( osteoarthritis of hip, Muscle related disease, Facet joint arthropathy ) Sacroiliac joint disease Neoplasm Peripheral nerve lesions Neuropathy (Diabetic, tumour , alcohol) Local sciatic nerve conditions (Trauma, tumour ) Inflammation (herpes zoster)

38. KEY DIAGNOSTIC POINTS LUMBAR DISC PROLAPSE Leg pain greater than back pain SLRT + Neurological deficit present ANNULAR TEARS Back pain greater than leg pain Bilateral SLRT positive FACET JOINT ARTHROPATHY Localized tenderness present unilaterally over joint Pain occurs immediately on spinal extension Pain exacerbated with ipsilateral side bending SPINAL STENOSIS Heaviness(no pain) develops after walks a limited distance. Flexion relieves symptoms No neurological deficit SLRT - ve MYOGENIC OR MUSCLE RELATED Pain localised to affected muscle Pain increases on prolonged muscle use Pain reproduced with sustained muscle contraction against resistance Contralateral pain with side bending

39. Investigations- Plain Radiographs FINDINGS: Loss of lumbar lordosis Loss of disc height

40. X ray views AP and Lateral views Oblique views Spondylolisthesis and lysis Hypertrophic changes around foramina in cervical spine Lateral flexion/ extension views Ferguson View 20 degrees caudocephalic AP fifth root compression by a large transverse process of the L5 vertebra against the ala of the sacrum. Angled caudal views facet or laminar pathological conditions.

41. X ray- Signs of Instability Indirect Signs Disc space narrowing, Sclerosis of end plates Osteophytes Traction spur Vacuum Sign Direct signs Translational abnormalities on dynamic films

42. Vacuum sign radiolucent defect presence of nitrogen gas accumulations in annular and nuclear degenerative fissures typical central vacuum phenomenon gas collection that fills large neo-cavity occupying both the nucleus an annulus. indicative of advanced disc degeneration.

43. CT scan Advantages: provides superior imaging of cortical and trabecular bone compared with MRI. It provides contrast resolution and identify root compressive lesions such as disc herniation . differentiate between bony osteophyte from soft disc. diagnose foraminal encroachment of disc material due to its ability to visualize beyond the limits of the dural sac and root sleeves. Limitations cannot differentiate between scar tissue and new disc herniation does not have sufficient soft tissue resolution to allow differentiation between annulus and nucleus

44. Investigations- MRI Most accurate and sensitive modality for the diagnosis of subtle spinal pathology . It allows direct visualization of herniated disc material and its relationship to neural tissue including intrathecal contents. Advantages over myelography No radiation Non invasive No intrathecal contrast More accurate in far lateral disc Disc disease of LS junction Early disc disease

45. Advantages of MRI over CT imaging the disc directly images neural structures shows the entire region of study (i.e., cervical, thoracic, or lumbar). ability to image the nerve root in the foramen Limitations Showing abnormal anatomy in asymptomatic patient. MRI findings can’t correlate with severity of symptoms.

46. Indications for MRI pain lasting > one month and not responding to non-operative management   or red flags are present infection (IV drug user, h/o of fever and chills) tumor (h/o or cancer) trauma (h/o car accident or fall) cauda equina syndrome (bowel/bladder changes)

47. Massive lumbar disc extrusion at L5–S1 in a 44-year-old man. Sagittal (a) and axial (b) T1-weighted images; sagittal (c) and axial (d) T2-weighted images. The extruded disc compresses and displaces the right S1 nerve root. On the sagittal T1-weighted image, the continuity between the extruding portion and the parent disc can clearly be identified.

48. GADOLINIUM ENHANCED CONTRAST MRI -Investigation of choice for recurrent disc prolapse -it allows to distinguish between post surgical fibrosis(enhances with gadolinium) and recurrent herniated disc(doesn’t enhance with gadolinium)

49. Myelography Unnecessary if clinical and CT or MRI findings are in complete agreement. Indications suspicion of an intraspinal lesion, patients with spinal instrumentation, questionable diagnosis resulting from conflicting clinical findings and other studies . previously operated spine marked bony degenerative change that may be underestimated on MRI arachnoiditis

50. Air contrast is used rarely -Only in situations in which the patient is extremely allergic to iodized materials

51. Discography- Uses Evaluate equivocal abnormality seen on myelography , CT or MRI Isolate a symptomatic disc among multiple level abnormality diagnose a lateral disc herniation establish discogenic pain select fusion levels evaluate the previously operated spine distinguish between mass effect from scar tissue or disc material

52. Electrodiagnostic studies Applied when clinical examination and imaging fail to provide a clear diagnosis or perhaps conflicting diagnoses May include needle electromyelography , somatosensory evoked potentials or cervical root stimulation May help differentiate primary cervical disorders from peripheral nerve entrapments syndromes or pain eminating from the intrinsic shoulder pathology

53. MANAGEMENT NON OPERATIVE MANAGEMENT 90% respond to conservative management Rest in semi-fowler position,ice packs, analgesics, muscle relaxants, oral steroids, physical therapy and exercises Selective nerve root blocks: transforaminal SNRB with local anesthetic agent and long acting corticosteroid combination Lumbar epidural steroid injection

54. Epidural Steroid injection Contraindications infection at the injection site systemic infection bleeding diathesis uncontrolled diabetes mellitus congestive heart failure. Complications Minor Non-positional headaches facial flushing insomnia low-grade fever, transient increased back or lower extremity pain Major vasovagal reaction Dural puncture Positional headache epidural abscess, epidural hematoma, Dura-cutaneous fistula, Cushing syndrome

55. Epidural Steroid injection Techniques Interlaminar Approach Transforaminal Approach Caudal Approach

56. Bed Rest no data to suggest that bed rest alters the natural history of lumbar disc herniation or improves outcomes. Consensus of 2 days (if used) Semi Fowlers Position

57. Physical Therapy Excercises Back School Others : IFT, SWD, TENS, Traction

58. Excercises Better than medical care alone Flexion-based isometric exercises appear to have the most support in the literature Offer benefit by decreasing local muscle spasm and stabilizing the spine. Begin when acute pain diminishes

59. Exercises GENERAL RULES FOR EXERCISE Do each exercise slowly. Hold the exercise position for a slow count of five. Start with five repetitions and work up to ten. Relax completely between each repetition. Do the exercises for 10 minutes twice a day. Care should be taken when doing exercises that are painful. A little pain when exercising is not necessarily bad. If pain is more or referred to the legs the patient may have overdone it. Do the exercises every day without fail.

60. FOR ACUTE STAGE BRIDGING EXERCISE KNEE HUGS

61. FOR RECOVERY OR SUBACUTE STAGE EXTENSION CONTROL HAMSTRING STRETCH KNEE ROLLS

62. Physical therapy TENS Trans-cutaneous electrical nerve stimulation release of endogenous analgesic endorphins Central nervous system process in which a control center is altered to block transmission of pain Deyo RA et al ‘TENS is no different from a placebo’ Intermittent Pelvic Traction Goal- distract the lumbar vertebrae. enlargement of the inter-vertebral foramen, creation of a vacuum to reduce herniated discs, placement of the PLL under tension to aid in reduction of herniated discs, relaxation of muscle spasm, freeing of adherent nerve roots Does not alter natural history of disease

63. Lifestyle Modifications Avoidance of Repetitive bending /twisting/ lifting Contact sports Heavy weights 2wheelers, Auto rickshaws Soft mattress( Spring, foam) Posture training Back support while sitting Firm mattress ( rubberised foam, coir )

64. Intra- discal Electrothermal Therapy Low back pain of discogenic origin Not useful in radiculopathy posterolateral placement of a probe around the inner circumference of the annulus followed by heating of the probe. Pre Requisites Normal neurology Negative SLR. absence of compressive lesions on MRI positive concordant discogram Conflicting outcomes requiring refinement of indications

65. Operative management Standard discectomy Limited Discectomy Microsurgical Lumbar discectomy Endoscopic discectomy Additional Exposure Hemi laminectomy Total Laminectomy Facetectomy Percutaneous Discectomy Chemo- nucleolysis Arthrodesis Disc replacement

66. SURGICAL MANAGEMENT   Indications     persistent disabling pain lasting more than 6 weeks that have failed non-operative options (and epidural injections)  progressive and significant weakness Cauda-equina syndrome Rehabilitation patients may return to medium to high-intensity activity at 4 to 6 weeks  Outcomes: improvement  in pain and function greater with surgery  Positive predictors for good outcome of surgery  leg pain is chief complaint  positive straight leg raise weakness that correlates with nerve root impingement seen on MRI married status Negative predictors for good outcome of surgery: worker’s compensation

67. STANDARD DISECTOMY Prone position With bolsters Knee chest position Allows abdomen to hang free, minimizing epidural venous dilation and bleeding Lateral position with affected side up

68. Salient Points Lamina exposed cephalad and caudad to the level of the herniated disc 1-2 sq cm area of lamina removed exposing dura and nerve root Visualise lateral edge of nerve root Remove sequestered disc Incise Annulus and remove central and lateral part of nucleus Nerve root must freely move 1cm inferomedially Foraminotomy Free fat graft to reduce post op scarring

69. Far lateral microdiskectomy   indications for far-lateral disc herniations   technique utilizes a paraspinal approach of Wiltse  

70. Additional Exposure Techniques Large disc herniation , lateral recess stenosis or foraminal stenosis , may require a greater exposure of the nerve root. If the extent of the lesion is known before surgery, the proper approach can be planned

71. Hemilaminectomy required when identifying the root is a problem. Eg . Conjoined root

72. Total Laminectomy Reserved for patients with spinal stenosIs that are central in nature, Occurs typically in cauda equina syndrome.

73. Facetectomy reserved for foraminal stenosis severe lateral recess stenosis If more than one facet is removed, a fusion should be considered Especially in a young, active individual with a normal disc height at that level.

74. Lumbar Microsurgical Discectomy first reported by Williams in 1978 procedure of choice for herniated lumbar disc Decompression of the involved nerve root with minimum trauma to the adjacent structures. Advantages decreased operative time, Decreased morbidity, less loss of blood, shorter stay in the hospital, earlier return to work. Visibility for assistant

75. Lumbar Microsurgical Discectomy Drawbacks inadequate exposure incomplete decompression Costly equipment Contraindications Previously operated Spinal Canal Stenosis

76. Microsurgical Lumbar Discectomy Requirements operating microscope with a 400-mm lens, small-angled Kerrison rongeurs of appropriate length, microinstruments , combination suction–nerve root retractor

77. Microsurgical Lumbar Discectomy Original Guidelines Avoidance of laminectomy and of trauma to the facets, Preservation of all extradural fat, Blunt perforation of the anulus fibrosus rather than incision with a scalpel, Preservation of healthy, non-herniated intervertebral disc material, Remove only as much disc as is necessary to relieve the neural elements from visible and palpable compression . New Guidelines Subtotal discectomy through an incision, made with a scalpel,in the anulus fibrosus ; using bipolar coagulation; Removing the medial portion of the facet for exposure when necessary

78. Percutaneous endoscopic Discectomy Mechanically decompress a herniated lumbar disc via a posterolateral cannula Reduced morbidity Reduced hospital stay No anaphylactic reactions and neurological complications associated with chemonucleolysis Contraindications Presence of sequestered fragments Lumbar canal stenosis Lumbosacral discs

79. Post op management Immediate post op Monitor neurology Turn in bed , semi fowler position Walk with assistance to toilet Oral analgesics and muscle relaxants for pain Bladder stimulants to assist in voiding Discharge- after walking and voiding(day of surgery in microscopic discectomy ) minimize sitting and riding in a vehicle to comfort Increase walking on a daily basis Avoid stooping bending lifting

80. Post op management Delayed Core strengthening between week 1 & 3 Lifting bending stooping gradually after 3 weeks Long trips avoid for 4-6weeks Walking jobs with minimal lifting 2-3weeks Prolonged sitting jobs 4-6 weeks Heavy labor, long driving 6-8weeks Exceptionally heavy manual labour - AVOID

81. COMPLICATIONS Infection – Superficial wound infection , Deep disc space infection Thrombophlebitis / Deep vein thrombosis Pulmonary embolism Dural tears may result in Pseudomeningocoele , CSF leak, Meningitis Postoperative cauda equine lesions Neurological damage or nerve root injury Urinary retention and urinary tract infection

82. CHEMONUCLEOLYSIS Chymopapain injected into the disc Degrades the proteoglycans in the nucleus Water holding capacity of the disc is decreased Shrinkage of the disc

83. Chemo nucleolysis Contraindications Sequestered disc Spinal stenosis previous injection of chymopapain allergy to papaya or its derivatives; Previous surgical treatment of the lumbar spine; herniation of more than two discs; a rapidly progressive neurological deficit; neurogenic dysfunction of the bowel or the bladder, or both; spondylohisthesis . Spinal tumour Pregnancy Diabetic neuropathy

84. Chemo nucleolysis Complications Neurological cerebral hemorrhage, paraplegia, paresis, quadriplegia, Guillain-Barre syndrome, seizure disorder. Anaphylaxis Procedure is not in favour now

85. Disc Excision & Arthrodesis First suggested by Mixter and Barr Indicated for Marked segmental instability Done when facets are destabilized bilaterally to prevent Iatrogenic Spondylolisthesis Disadvantages of fusion: Alters the biomechanics of spine Loss of motion and overall shift in the sagittal alignment Causes degenerative changes in the adjacent spinal motion segments

86. Total Disc Replacement CHARITE artificial disc ( Depuy spine) was the first implant approved by FDA for total disc replacement in october 2004. Presently , there are only three lumbar disc prostheses with FDA approval: the INMOTION, which is a modification of the Charite ( Depuy Spine, Raynham, MA), the ProDisc -L ( DePuy Synthes ), the activL ( Aesculap , Center Valley,PA ). All are approved only for single-level disc replacement.

87. ADVANTAGES OF DISC REPLACEMENT Removes the disc/presumed main source of pain Restore disc height----relieves load across the facet joints----improves the pattern of load bearing between vertebrae. Segmental stability, preservation and improvement of segmental motion Maintain lordosis curve Limit disability and early return to work

88. PRE REQUISITES FOR DISC REPLACEMENT Normal facet joints Good bone quality(non osteoporotic) No spondylolisthesis or spinal deformity No infection Single disc level

89. PRO DISC L

90. PRO DISC L

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