1. Mechanical Disorders : Intervetebral Disc
Dr Munir Saadeddin

5. Disorders of Intervertebral Disc
Are thought to be the cause of most cases of low back pain
Are common at middle age
Result from loss of hydration of the Annulus Pulposis or major trauma to disc

6. Function of Intervertebral Disc
It functions as a cushioning structure
It is a structure of shock absorption
The amount of pressure inside the disc varies according to posture of human
Normally it does not encroach on spinal canal posteriorly

7. Anatomy of Intervertebral Disc

8. Anatomy of Intervertebral Disc

9. Fresh Cadaver Specimen of a Disc

10. Anatomy of Intervertebral disc
The disc is a biconvex structur
It consists of outer layer of Interlaced fibers called Annulus Fibrosis and central layer called Nucleolus Pulposis
The Nucleolus is soft, elastic and well hydrated structure at young age

11. Pressure inside the Disc
Least pressure is when person is lying flat
Pressure increases 3 folds on twisting in bed
Pressure increases 4 folds when standing

12. Pressure inside the Disc
Pressure increases 6 folds on forward bending
Pressure increases 10 folds on bending and lifting
This explains the most common cause for rupture of intervertebral disc

13. Pressure inside the Disc

14. Circumferential Tear in Annulus

15. Radial Tears of Disc
Radial tears are more serious than circumferential tears
Circumferential tears cause deep seated backache but radial tears may lead to bulge in the annulus inside the spinal canal or protrusion of nucleolus inside the canal

16. Protrusion of Intervertebral Disc
Usually it is posterolateral as the posterior longitudinal ligament resist central posterior protrusions
Central protrusions are usually small, but large protrusions are more serious as they may cause Cauda Equina Syndrome

17. Protrusion of Disc

18. Nerve Root Protrusion by PID
Protrusion of Intervertebral disc may compress the nerve root exiting spinal canal at that level and may cause inflammatory change
Protrusion at L4-L5 compresses L5
Protrusion at L5-S1 compresses S1

20. Central Disc Protrusions
May compress More than one nerve root
It does compress central roots like S2 S3 / S4
This leads to compression of nerve roots to bladder and rectum ( Cauda Equina Syndrome )

21. Clinical Picture of PID

22. Clinical Picture of PID
A middle age mal
May present with LBP and or Sciatica (Though sciatica in Arabic is referred to as painful leg in women )
Sometimes follows clear incident of heavy lifting or back straining
Frequently NO history of any cause is present

23. Clinical Picture of PID
May present as : Acute , Recurrent or Chronic
In Acute cases patient may report that he felt a tear or a click at his back
This may be followed by immediate radiation of pain to leg or not
Radiation to leg may appear later

24. Clinical Picture of PID
This is NOT a systemic disease
There is NO fever or weight loss
PAIN IS MECHANICAL i.e. : it follows some posture which increases the intervertebral disc pressure
Constant pain or nocturnal (night) pain is a sinister sign
Pain is increased by coughing and relieved by lying in bed

25. Usually it is the lower back
Commonly there is Para vertebral muscle spasm
We palpate the level of Iliac Crest = level of L4-L5

26. Palpation in Back Examination
We can palpate the Para Spinal muscles ,tips of spinous processes and the inter spinal ligament
We cannot palpate the lamina , the disc or vertebral body

27. Palpation in Back Examination
We start by identifying the level of Iliac Crest
This corresponds to L4-L5
Almost 5 cm below is L5-S1
Below on the sides there is a dimple which corresponds to upper S.I. Joint

28. Palpation in Back examination
Lesions at L4-L5 will produce tenderness at L4-L5 level
Lesions at L5-S1 will produce tenderness at L5-S1 level
We can palpate for tenderness at Sciatic Nerve course as well

29. Examination of Back Movements: Forward Flexion
Forward flexion is 90 degrees or when tips of fingers reach level of malleoli
Flexion to level of mid-tibia is 60 degrees
Flexion to knees is 45 degrees
Flexion to mid-Thigh is 30 degrees

30. Examination of back movements: Back Extension
From straight to 30 degrees
Some people can do much more (Gymnastics or people with ligament laxity )
Back extension is reduced or lost in people with acute PID ( It may be even –Minus extension as they may walk with flexed back )

31. Examination of Back Movements: Lateral Flexion
Lateral flexion is 30 degrees to right or left
Lateral flexion to the same side of pain is always restricted (except in case of axial disc herniation)

33. Examination of Back Movements: Rotation
May be done in EITHER standing or sitting positions
In standing position examiner has to immobilise the pelvis of the patient to make sure than there is no rotation of whole body
In sitting position body weight immobilises the pelvis and probably more accurate

34. Walking on Heels = L5
Asking the patient to stand and walk on his heels elicit if there is any weakness at L5 (which is main nerve root for All 3 muscles of dorsiflexion = Tibialis Anterior , Extensor Digitorum and Extensor Hallucis Longus)

35. Walking on Tip Toes = S1
Asking the patient to stand and walk on tip toes elicit if there is any weakness of S1 (which is the main nerve root for muscles of plantar flexion = Gastocnemius and Soleus

36. Examination in Supine position
Once we ask patient to lie down in bed we start examining certain tests
This does NOT include inspection of the back
Most important is SLR test ( Straight Leg Raising Test ) and Neurological assessment for the condition

37. Straight Leg Raising Test

38. SLR Test It is a Sciatic Nerve Stretch Test Normally it is Painless
Is done in supine position
Normal from 0-90 degrees
Reliable test is between 30-80

39. Lasague Maneuver

40. Lasague Maneuver Lasague Maneuver is a modified SLR test
It has 3 advantages
It is a confirmatory test for SLR
It excludes hip or knee pain as a cause for the pain on SLR
It excludes malingering patients

41. Lesions of L3-4 and L4-5

42. Lesions of L4-5 and L5-S1

43. Investigations of Backache : x rays
Plain X Rays are useful
AP, Lateral and Oblique may be done
On this lateral view there is obvious sign = Loss of normal lordosis =straitening of lumbar spine

44. Investigations of Backache : x rays
Lateral view or cone view demonstrate narrowed disc space
Also this view demonstrates gas shadow in disc space= chronicity= Knott’s sign = vacuum phenomenon

45. Myelography and radiculography
Used to be the most important test for eliciting disc protrusions
NOT used these days for the above diagnosis
Still used for investigating certain intra spinal and instability conditions

46. C.T. Scan Disc Protrusion

47. C.T. Myelography

48. MRI L4-5 PID

49. MRI : P I D

50. MRI : PID=LDH

51. MRI : PID = LDH

53. Management of PID Essentially conservative
Almost 85% respond to conservative treatment
Up to 15% surgical treatment is indicated
Severity of symptoms does not indicate severity of disease

54. Conservative Treatment
Should be tried initially in most cases
Short period of Bed Rest (< 1 week ) should be tried in ACUTE cases
Bed rest is NOT indicated in chronic cases
NSAID’s and muscle relaxants are used ( Drugs to protect against G.I. effects especially in the elderly )
Avoids narcotics

55. Physiotherapy and Exercises
Are the most important tools in management
Always should be part of treatment
Weight reduction and back care education
Heat therapy especially Short Wave diathermy and Ultrasound important types of treatments
Exercises to strengthen back and abdominal muscles should be done

56. Chiropractic Therapy & Acupuncture
Recently gaining popularity
Chiropractics means re-alignment of bones and joints to normal structure (However once we understand the pathology of PID, it is difficult to see how can a disc be put back in place!)
Acupuncture is by stimulating specific points by needles and is helpful in some patients

57. Steroid Injections In PID
In selected cases they are valuable adjuvant to other modalities of treatment
They are injected in the Extradural space by lumbar or caudal route
It is believed they work by reducing the inflammatory changes in the nerve root associated with PID

58. Surgery in PID Radiological evidence MUST be obtained prior to surgery
Theses radiological changes MUST correspond with the clinical picture
We have to remember that NOT every bulging disc should be operated on
MRI is the golden standard in diagnosis

59. Indications for Surgery for PID
There are Five indications
Only one definite and urgent indication in CAUDA EQUINA syndrome
Three valid and correct indications (will be explained soon )
One controversial and personal indication

60. Valid Indications for Surgery in PID
Failure of conservative treatment ( for at least 6 weeks ) and continuation of pain
Progression of neurological deficit (but initial deficit is not an absolute indication )
Recurrent and disturbing attacks

61. Controversial indications in PID
Time Factor : Patient is not prepared to complete a full period of conservative treatment ( 6 weeks ) to see if it will succeed
Patient’s preference
Surgeon’s preference

62. Exclude a psychological causes

64. Operative procedures for PID
At least 15% of cases of PID end up having surgery
At USA : at least cases are operated on annually
At USA : there are 7 million individuals who had back surgery
Still at USA : there are 21 million people with disability certificate due to backache !

65. Aim of surgery for PID To relieve patient of his pain
Leg pain can be relieved by removing pressure on nerve root ( Decompression of nerve root )
This is done by removing the bulged or protruded part of the disc and any other part which can be curetted out
Back pain can be relieved by stabilising that intervertebral disc segment

66. Position for surgery for PID

67. Position for surgery for PID
Usually it is Chest-Knee position
This is to avoid any pressure on abdomen
Avoidance of pressure on abdomen reduces intra abdominal pressure and consequently reduces intra spinal pressure = reduction of venous bleeding from dural veins

68. Open Disc Surgery 3-5 cm for each disc level
Lamina above and lamina below are exposed with the part of Ligamentum Flavum between
Part of Ligamentum Flavum and lamina is removed to get access to spinal canal

69. Open Disc Surgery

70. Exposure of Dura and Nerve Root

71. Excision of protruded PID
Dura is retracted with the nerve root to expose the protruded PID
Once protrusion is exposed it is incised in 5x5 mm cruciate incision
Occasionally nucleolus is already penetrated through the annuulus

72. Excision of PID
Protruded or extruded disc is removed and disc space curetted
Nerve root should be Free from any compression and Free from tension
If any bone was involved it should be removed

73. Endoscopic Micro- Discectomy
Relatively New method of Disc Surgery
Minimally traumatic in experienced hands
Minimal scar and blood loss
Requires high quality surgical tools
Fluoroscopy pre and during surgery is necessary
Nerve root injury may be as high or even higher than with other methods

74. Endoscopic Micro- Discectomy

75. Endoscopic Micro- Discectomy

77. Percutaneous Discectomy
Is done through a cannula inserted lateral to midline into disc space under G.A. or L.A. and nucleolus is sucked with shaver
Initially was thought to be easy and simple
Has not proved to be very successful
Reported success rate is 70%
Patient and surgeon are exposed to repeated radiation

78. Percutaneous Discectomy

80. Laser Discectomy
May become the golden standard for managing PID in the future ( especially when open MRI machines are available )
Route of entry is similar to Percutaneous Discectomy
Can be done under local or general anesthesia
Not perfect at present