Chapter 62 Peripheral Nerve Stimulation

Question 1

PNS used for a wide variety of chronic pain disorders

Answer 1

limb mononeuropathies, complex regional pain
syndrome, cranial neuralgias, headache disorders, and
regional pain not amenable to SCS

Question 2

Theories of pain pathophysiology of how neuromodulation affects
chronic pain

Answer 2

direct effects on peripheral pain fibers through excitation failure, selective release of
pain-modulating neurotransmitters, and changes in cerebral
flow in pain centers.

Question 3

an important

consideration when attempting to stimulate a sensory fascicle

Answer 3

The complex fascicular arrangement of upper extremity nerves

Question 4

peripheral nerve arrangements

Answer 4

will have one to several
internal fascicles that routinely change locations within the
nerve topography.

Question 5

An open neurosurgical approach allows what testing

Answer 5

only motor testing with a nerve stimulator, unless

the operator performs a wake-up test.

Question 6

Ultrasound allows

Answer 6

The key nerves of interest are usually superficial
enough to be seen well under US. US also allows visualization of surrounding key soft tissue structures and in each case, care should be taken to not pierce muscle compartments
or vascular structures along the needle/lead path to the nerve

Question 7

For implantation cases, the lead can be anchored

to

Answer 7

the superficial muscle fascia with a strain relief

loop.

Question 8

redundancy of the number of lead contacts in the vicinity of the desired fascicle is important because

Answer 8

The nerve will normally translate within the neurovascular
compartment as much as several millimeters. This
means that a normal nerve may move up to several millimeters
between the muscle and surrounding fascia with
flexion, extension, and rotation of the extremity

Question 9

The radial nerve is very close to the lateral surface of the humerus at a point

Answer 9

10 to 14 cm proximal to the lateral epicondyle

Question 10

RADIAL NERVE PNS technique

Answer 10

Ultrasound scanning usually begins at the
elbow and, with the probe in a transverse orientation to the arm, continues proximally until the desired approach
is identified. The needle can be advanced
from posterolateral to anteromedial to lie between nerve and humerus.

Question 11

RADIAL NERVE PNS indications

Answer 11

Potential patients could include those with posterior interosseous neuropathies or
resistant lateral epicondylitis (tennis elbow) patients.

Question 12

Solution of problems with lead migration

Answer 12

Subsequent radial nerve placements have utilized
more than one electrode, and a 4-week period of soft arm immobilization to allow the electrode(s) to better fibrose into place.

Question 13

ULNAR NERVE location

Answer 13

The ulnar nerve is superficial to the medial head of the triceps muscle. the nerve was easily identified at a point 9 to 13 cm proximal
to the medial epicondyle in the medial/posterior
arm.

Question 14

ULNAR NERVE PNS technique

Answer 14

Ultrasound scanning can commence at the elbow
and, with the probe in a transverse orientation to the arm, continue to scan more proximally until the nerve fascicular
arrangements can be well identified. The needle may be advanced from posterior to anterior on the medial aspect
of the arm to lie between nerve and humerus, staying superficial to the medial head of the triceps.

Question 15

In ULNAR NERVE PNS Caution is important to avoid injury to the

Answer 15

medial cutaneous nerve of the arm, as well as

the recurrent ulnar collateral artery

Question 16

MEDIAN NERVE location

Answer 16

The median nerve enters the antecubital fossa medial to the biceps muscle and its tendon, and next to the brachial artery. In the upper forearm at a point
approximately 4 to 6 cm distal to the antecubital crease, the nerve passes between the two heads of the pronator teres muscle, and then passes under the sublimis bridge of
the two heads of the flexor digitorum superficialis

Question 17

in the forearm an important consideration in terms of expected stimulation patterns of the Median nerve

Answer 17

common neural fascicular communications between the median and ulnar nerves

Question 18

Median nerve stimulation may be accomplished either

Answer 18

superior to the elbow, or inferior.

Question 19

The common peroneal nerve may be identified at its branch point from

Answer 19

the sciatic nerve, a point 6 to 12 cm proximal to the popliteal crease

Question 20

POPLITEAL AREA PNS Technique

Answer 20

Either transverse or longitudinal placement can be used, with transverse placement being more forgiving of movement, but a greater number of possible electrodes contacting
the nerves with longitudinal placement. The needle may be
advanced from posterolateral to anteromedial in a slightly
oblique plane, attempting to avoid passing through the biceps femoris.

Question 21

POPLITEAL AREA PNS One must also scan thoroughly to see

Answer 21

the sural branches to

avoid injury

Question 22

POSTERIOR TIBIAL location

Answer 22

Approximately 8 to 14 cm proximal to the
medial malleolus, the nerve is in close proximity to the tibialis
posterior muscle, the digitorum profundus, one or two large veins, and the flexor hallucis longus.

Question 23

POPLITEAL AREA PNS technique

Answer 23

US scanning begins
at the ankle near the medial malleolus, with the probe in a transverse orientation to the leg, and then continued
proximally until the desired approach is identified. The needle may be advanced from anterior to posterior along the medial aspect of the ankle to lie just superficial (or deep)
to the nerve.