Principles of Nerve Repair

Question 1

The perineurium serves to bundle axons together to form fascicles and is a major contributor to peripheral nerve tensile strength

Answer 1

T

Question 2

Wallerian degeneration process begins within 24 to 48 hours of injury and involves complete axonal degeneration distal to the site of injury

Answer 2

T

Question 3

Wallerian degeneration halts at
the closest intact node of Ranvier, which also serves as the site of subsequent axonal growth

Answer 3

T

Question 4

dedifferentiated Schwann cells proliferate
along the residual endoneurial tubes and create columns known as
Bands of Biingner

Answer 4

T

Question 5

superior clinical outcomes are observed when endoneurial tube remains
intact

Answer 5

T

Question 6

Axonal regeneration occurs at a rate of approximately 1 to 3 cm/ day

Answer 6

F Axonal regeneration occurs at a rate of approximately 1 to 3 mm
per day or just slightly more than an inch per month

Question 7

sensory end organs do
not undergo such degeneration and can be reinnervated many years
later with satisfactory results

Answer 7

T

Question 8

scarring can be present in third degree nerve injury

Answer 8

T

Question 9

include traction and iatrogenic
nerve injection can result in third degree nerve injury

Answer 9

F 4th degree

Question 10

here is no diagnostic test to distinguish between second-, third-, and fourth-degree
injuries

Answer 10

T

Question 11

Fibrillations and positive sharp
waves (PSWs) on needle EMG indicate first -degree Sunderland injury

Answer 11

F Fibrillations and positive sharp
waves (PSWs) on needle EMG indicate axonal loss and therefore at
least second-degree Sunderland injury

Question 12

PSWs can be observed as early as 3 weeks after nerve injury

Answer 12

T

Question 13

fibrillations are typically observed around 6 weeks after nerve injury

Answer 13

T

Question 14

The presence of fibrillations and PSWs on EMG are significant to
the prognosis why?

Answer 14

because they reveal that the distal motor plates in the
target muscle fibers are still available for reinnervation

Question 15

The size,
shape, and recruitment pattern of motor unit potentials (MUPs) on
needle EMG is helpful in determining the duration of nerve injury
and the expected potential for functional recovery

Answer 15

T

Question 16

The reappearance of MUPs on
EMG about 12 weeks after injury represents second- and
third-degree Sunderland nerve injuries

Answer 16

T

Question 17

Electrodiagnostic studies may be obtained immediately after significant trauma

Answer 17

T

Question 18

The harvested nerve
graft undergoes Wallerian degeneration

Answer 18

t

Question 19

nerve innervating a free muscle transfer can be considered as a possible graft

Answer 19

T

Question 20

The autograft should be placed in
reversed orientation at the repair site to prevent loss of regenerating
axons down side branches

Answer 20

T

Question 21

In nerve Allograftsthe recipient should receive immunosuppression for two years

Answer 21

T

Question 22

Conduit can lead to formation scar tissue

Answer 22

F The absorbable nature
of these conduits limits the associated foreign body reaction that can
result in scar tissue encapsulation and subsequent inhibition of axonal growth

Question 23

Stem cells and Schwann cells seeded
into nerve conduits have demonstrated significantly better functional
outcomes compared with empty conduits

Answer 23

T

Question 24

these constructs have been shown to
support successful nerve regeneration across small diameter nerves
with gaps up to 3 cm or with large diameter nerves with gaps less than
0.5 cm.

Answer 24

T

Question 25

for motor defects or nerve defects that span more than 3 cm, autologous nerve grafting is still considered the standard of care

Answer 25

T

Question 26

When an end-to-end repair is planned, the donor's nerve is ideally transected as proximally as possible to

Answer 26

F When an end-to-end repair is planned, the donor nerve is ideally transected as distally as possible and the recipient nerve is transected as proximally as possible to optimize a tension-free coaptation

Question 27

In Younger patients, distal nerve repairs do better than proximal repairs

Answer 27

T

Question 28

pure sensory or pure motor nerve repairs do better than mixed nerve repairs

Answer 28

T

Question 29

, VTE, per se, is not a contraindication to free tissue transfer

Answer 29

T

Question 30

Topical papaverine works by blocking sodium channels

Answer 30

F Topical papaverine works by blocking calcium (not sodium) channels

Question 31

Transcutaneous tissue oximetry can detect vascular compromise before clinical signs alter

Answer 31

T

Question 32

The use of systemic heparin increases the risk of postoperative bleeding, but its action is short-lived compared with low molecular heparin

Answer 32

T

Question 33

When functional connections are not made in a timely fashion, axons can degenerate in a process known as pruning

Answer 33

T

Question 34

Amplitude of the recorded CMAPs provides an estimate of the number of intact motor axons activating muscle fibers.

Answer 34

T

Question 35

The reappearance of MUPs on EMG about 12 weeks after injury reflects the collateral sprouting of adjacent, uninjured nerve fibers and thus represents second- and third-degree Sunderland nerve injuries

Answer 35

T

Question 36

in fourth- or fifth-degree Sunderland injuries, MUPs are not typically seen on EMG because all of the axons have lost continuity with their target muscle fibers.

Answer 36

T

Question 37

Total division of a peripheral nerve may be better diagnosed with imaging studies such as ultrasound or magnetic resonance imaging.

Answer 37

T

Question 38

Medial antebrachial cutaneous nerve provides up to 20 cm of length and the LABC up to 8 cm

Answer 38

T

Question 39

motor nerves grafts are thus reserved for instances where no sensory donors are available and nerve transfers would not provide a better option

Answer 39

T

Question 40

Allografts can be decellularized to avoid the need for immunosuppression

Answer 40

T

Question 41

all alternatives to autologous nerve grafts, including decellularized allografts and tissue-engineered conduits, demonstrate similar efficacy in reconstruction of sensory nerve defects of less than 3 cm

Answer 41

T

Question 42

Synthetic nerve conduit reconstruction of nerve has not proven effective in gaps longer than 2 cm and is less effective in motor nerve defects.

Answer 42

T

Question 43

The LABC nerve is the distal continuation of the musculocutaneous nerve.

Answer 43

T

Question 44

Minimal tension and an increasing number of suture strands crossing the repair site are both associated with improved function.

Answer 44

T