Lumbar disc Herniation

Question 1

What is the most common level involved ?

Answer 1

L5/S1 most common

but L4/5

Question 2

What is the peak age of incidence?

Answer 2

4th and 5th decades

Question 3

What percentage become symptomatic?

Answer 3

5%

Question 4

what is the male:female ratio?

Answer 4

3male to 1 female

Question 5

Describe the pathoantomy?

Answer 5

RECURRENT TORSIONAL STRAIN-> TEARS OF OUTER ANNULUS which leads to HERNIATION of the NUCLEUS PULPOSIS

Question 6

What is the prognosis of lumbar disc herniations?

Answer 6

90% of patients will have improvements of symptoms at 3 months with NON-OP
SIZE of herniation DECREASES WITH TIME

Question 7

Which type of discs show the greatest degree of spontaneous reabsorption?

Answer 7

SEQUESTERED DISC

Question 8

What is the mechanism of reasbsorportion?

Answer 8

MACROPHAGE PHAGOCYTOSIS

Question 9

What is the disc composed of?

Answer 9

ANNULUS FIBROSIS- outside
of TYPE 1 COLLAGEN, h20 and proteoglycans
characterised by EXTENSIBILITY + TENSILE STRENGTH- high collagen low proteoglycan

NUCLEUS PULPOSUS
of TYPE 2 COLLAGEN, h20, proteglycans
characterised by COMPRESSIBILTY- low collagen, high proteoglycan ( pg inexact w h20 and resist compression)

Question 10

Describe the nerve root anatomy?

Answer 10

there are 2 key differences between the cervical and lumbar spine with respect to pathology and level
1) PEDICLE/ NERVE ROOT MISMATCH
Cervical spine C6 n root travels under C5 pedicle ( mismatch)
lumbar spine L5 n root travels under L5 ( match)
extra C8 n root ( no C8 pedicle) allows transition
2) HORIZONTAL (Cervical) vs VERTICAL (Lumbar) anatomy of nerve root

because vertical anatomy of lumbar nerve root - a paracentral and foramina disc will affect different nerve roots- i.e.far lateral disc at L4/5 will effect L4 n root cf paracentral L4/5 will effect L5 n root

because of horizontal anatomy of CERVICAL n root a central of foramina disc will effect the SAME n ROOT

Question 11

Can you describe the LOCATION classification of disc prolapse?

Answer 11

CENTRAL - assoc w back pain only
may pc CAUDA EQUINA- surgical ER

POSTERIOLATERAL (paracentral)
                   most common 90-95%
                   PLL is weakest here
       affects transversing/descending lower root-
       at L4/5 affects L5

FORAMINAL ( FAR LATERAL)
less common 5-10%
affects exiting/UPPER n root -
at L4/5 affects L4

AXILLARY- can effect both exiting and descending nerve roots

Question 12

Can you describe the ANATOMICAL classification of disc prolapse?

Answer 12

PROTRUSION- Eccentric bulging with intact
ANNULUS

EXTRUSION- Disc material HERNIATES thru ANNULUS but remains continuous with disc space

SEQUESTERED FRAGMENTS (free)
Disc material herniates thru ANNULUS and is no longer continuous with disc space

Question 13

What do patients present with?

Answer 13

AXIAL BACK PAIN- discogenic/mechanical in nature

RADICULAR PAIN- buttock/leg pain
often worse with SITTING,improves with standing
symptoms worsened by coughing,valsalva, sneezing

CAUDA EQUINA SYNDROME -present 1-10%
bilateral leg pain
saddle anaethesia
bladder/bowel symptoms
LE weakness

Question 14

What do you see on examination?

Answer 14

motor exam
ankle dorsilfexion L4/5
EHL weakness L5
Hip abduction L5
Foot plantiflexion S1

provocation tests
Straight leg raise - tension side for L5/s1 n root
-> pain and parasthesia in leg at 30-70 degrees of hip flexion

gait- trendelenburg gait- due to glut medius weakness innervated by L5

Question 15

What imaging can be used ?

Answer 15

xray- loss of lordosis
loss of disc height
lumbar spondylosis - degenerative change

MRI wout gadolium
mode of choice to identify lumbar/cervical disc herniations
high sensitivity and specificity
helpful preop planning
high rate of abnormal findings on MRI in Normal pt

Question 16

what are the indications to obtaining an MRI scan?

Answer 16

Pain lasting for > 1 month and NOT RESPONDING to non-operative management
red flags= INFECTION
                 IV DRUG USER
                 TUMOUR
                  TRAUMA
                  CAUDA EQUINA syndrome

Question 17

What are the tx options?

Answer 17

Non operative- rest, physical therapy and anti-inflammatory medications
1st line of tx for most patients with disc herniation- 90% improvement without surgery
- Bedrest then increased activity- extension exercises, pilates
medication- nsaids, muscle relaxants, oral steriod taper

outcome- similar results between operative and non operative at 4 years

Question 18

What other non operative tx are there?

Answer 18

Selective nerve root corticosteriod injections
1st line of tx if therapy and medications fail
epidural/selective nerve block
outcome-> long lasting improvement in 50%
results best in pt with EXTRUDED discs as opposed to contained discs

Question 19

What are the surgical options and their indications?

Answer 19

LAMINOTOMY and DISCECTOMY ( MICRODISCECTOMY)
indications- PERSISTENT DISABLING PAIN lasting more than 6/52 failed non op mx
PROGRESSIVE and SIGNIFICANT WEAKNESS
CAUDA EQUINA SYNDROME

Question 20

What are the outcomes of surgery cf nonop?

Answer 20

Improvement in pain and function
70% improvement in pain
neurological recovery less predictable 
50% motor /sensory recovery
25% reflex recovery

Question 21

What are the complications from surgery?

Answer 21

DURAL TEAR-1% if at time of surgery then perform water tight repair
RECURRENT HNP- can tx non operatively
DISCITIS- 1%
VASCULAR CATASTROPHE - causing by breaking thru anterior annulus and injuring vena cava/aorta