Ch. 13 - Low back pain and leg pain

Question 1

What is the critical factor in assessing pts with low back pain?

Answer 1

Whether there are features of lumbosacral nerve root compression

Question 2

What is sciatica?

Answer 2

Clinical description of pain in leg 2/2 lumbosacral nerve root compression

Question 3

Most common cause of sciatica

Answer 3

Lumbar disc prolapse causing nerve root compression Other: osteophyte compression, lumbar canal stenosis, spondylolithesis

Question 4

Most common level of lumbar disc prolapse

Answer 4

L5/S1

Question 5

Components of interverterbal disc

Answer 5

Internal nucleus pulposus surrounded by annulus fibrosus (external laminar fibrous container)

Question 6

Disc prolapse is most common in what direction?

Answer 6

Posterolateral direction b/c posterior longitudinal ligament prevents direct posterior herniation

Question 7

An L4/5 POSTEROLATERAL disc prolapse will compress which nerve root?

Answer 7

L5

Question 8

An L5/S1 POSTEROLATERAL disc prolapse will compress which nerve root?

Answer 8

S1

Question 9

An L4/5 LATERAL disc prolapse will cause compression of which nerve root?

Answer 9

L4

Question 10

Describe the different types of disc prolapse

Answer 10

A) Posterolateral disc prolapse -> compression of nerve root below

B) Lateral disc prolapse -> compression of nerve root above

Question 11

Features of L5/S1 disc prolapse

Answer 11

Pain along posterior thigh with radiation to heel

Plantar flexion weakness

Lateral foot sensory loss

Absent ankle jerk

Question 12

Features of L4/5 disc prolapse

Answer 12

Pain along posterior or posterolateral thigh with radiation into dorsum of foot and great toe

Dorsiflexion weakness

Decreased sensation of dorsum of foot and great toe

No reflex changes

Question 13

Features of L3/4 disc prolapse

Answer 13

Pain in anterior thigh

Quadricep (with quadricep wasting) and dorsiflexion weakness

Decreased sensation over anterior thigh, kknee, and medial aspect of lower leg

Reduced knee jerk

Question 14

Innervation of hip flexors? Extensors?

Answer 14

Flexors - L1, 2, 3

Extensors - L5, S1

Question 15

Innervation of knee flexors? Extensors?

Answer 15

Flexors - L5, S1

Extensors - L3, 4

Question 16

Innervation of ankle dorsiflexors? Plantar flexors?

Answer 16

Dorsiflexors - L4, 5

Plantar flexors - S1, 2

Question 17

How long do most cases of back and leg pain take to resolve?

Answer 17

7-10 days

Question 18

What should you order for evaluation of back/leg pain?

Answer 18

X-ray to diagnose associated spondylolisthesis and exclude sinister pathology (e.g. spinal mets)

ESR to exclude systemic dx

Question 19

What are the indications for surgical intervention in disc prolapse?

Answer 19

Incapacitating pain, continuing episodes of recurrent pain, neurologic deficit (e.g. weakness), bilateral sciatica (suggests central disc prolapse), tumor

Question 20

Imaging study of choice for disc prolapse?

Answer 20

MRI

Question 21

Surgical options for lumbar disc prolapse

Answer 21

Usually partial laminectomy + disc excision

Percutaneous lumbar discectomy (remove nucleus pulposus) for ‘bulging’ disc

Question 22

Criteria that suggest better results following disc prolapse surgery

Answer 22

Good hx of sciatica, good signs of nerve root irritation, evidence of herniated disc, nerve root stretched by disc at time of surgery, pt is motivated

Question 23

Characteristic feature of lumbar canal stenosis

Answer 23

Pain is relieved with sitting (‘shopping cart’ sign)

Question 24

What are the most common levels affected by lumbar canal stenosis?

Answer 24

L4/5 and L3/4

Question 25

Surgical tx of lumbar canal stenosis

Answer 25

Decompressive lumbar laminectomy

Question 26

What intra-abdominal pathology should be considered in a patient with back pain?

Answer 26

Pancreatic dx - pancreatitis or tumors

Aortic aneurysm

Renal dx - calculus, infection, tumor

Question 27

What is spondylolisthesis?

Answer 27

Subluxation of one vertebral body on another (usually L4 or L5); can be congenital or 2/2 degenerative changes

Question 28

Tx of spondylolisthesis

Answer 28

Conservative therapy, laminectomy +/- spinal fusion

Symptomatic patients with grade 2 or above slip have a clear benefit with surgery!