Chapter 15 Peripheral Nerve Blocks
1. Name some types of peripheral nerve blocks.
2. Other than as anesthesia for a surgical procedure, what are some uses for peripheral nerve blocks?
3. What are some special considerations that should be made in the preoperative evaluation of a patient who is to undergo a peripheral nerve block?
Specific block techniques
7. What are some of the advantages of ultrasound-guided peripheral nerve blocks?
8. Describe the macroscopic cross-sectional appearance of peripheral nerves.
9. When using high-resolution ultrasound, what percent of the fascicles within a peripheral nerve are able to be visualized?
10. Describe the sonographic appearance of a proximal nerve.
11. What are the image characteristics of high-frequency ultrasound compared with low frequency?
12. What factors affect ultrasound visibility of needles?
13. Describe the short axis and long axis scanning orientations.
14. Describe the in-plane and out-of-plane needle approaches.
15. What is the significance of a paresthesia during block performance?
16. Describe cathodal stimulation and the significance of electrode reversal in evoking a motor response from a peripheral nerve.
17. What is an optimal stimulating threshold for nerve stimulator technique before injection of local anesthetic?
Brachial plexus block
23. For what surgical procedures is a brachial plexus block useful? What areas become anesthetized by a brachial plexus block?
24. What nerve roots form the brachial plexus?
25. What landmarks are used to locate the brachial plexus for blockade?
26. What are four different approaches to blockade of the brachial plexus?
27. How is a brachial plexus block via the interscalene approach achieved? What volume of local anesthetic is deposited with this approach to brachial plexus blockade?
28. What are some advantages of brachial plexus blockade via the interscalene approach?
29. What is a disadvantage of brachial plexus blockade via the interscalene approach?
30. What are some potential complications of brachial plexus blockade via the interscalene approach?
31. How is a brachial plexus block via the supraclavicular approach achieved? What volume of local anesthetic is deposited with this approach to brachial plexus blockade?
32. What are some advantages of brachial plexus blockade via the supraclavicular approach?
33. What are some potential complications of brachial plexus blockade via the supraclavicular approach?
34. Describe the in-plane ultrasound-guided technique for blockade of the brachial plexus via the axillary approach. What volume of local anesthetic is deposited with this approach to brachial plexus blockade?
35. Axillary block provides anesthesia for surgery in which regions of the upper extremity?
36. What nerves are blocked by injection superficial to the axillary sheath during the axillary brachial plexus block? How is this achieved?
37. What are some advantages of brachial plexus blockade via the axillary approach?
38. What are some potential complications of brachial plexus blockade via the axillary approach?
Distal nerve blocks of the upper extremity
39. What is the sensory distribution of the median nerve? How is it blocked at the forearm with ultrasound guidance?
40. What is the sensory distribution of the ulnar nerve? How is it blocked at the forearm with ultrasound guidance?
41. What is the sensory distribution of the radial nerve? What is the typical course of the superficial radial nerve through the forearm, and how is it blocked at the forearm with ultrasound guidance?
Blocks of the lower extremity
42. What are the challenges of lower extremity blocks relative to those of the upper extremity?
43. What are the four major nerves of the lower extremity?
44. What nerves form the sciatic nerve, and what are its approximate dimensions in the pelvis?
45. What area is anesthetized by sciatic nerve blockade and what additional blocks are usually necessary to provide lower extremity anesthesia?
46. How is sciatic nerve blockade achieved? What volume of local anesthetic should be deposited for sciatic nerve blockade?
47. What nerves form the femoral nerve? How does it reach the thigh? What is the terminal branch of the femoral nerve?
48. For what procedure is femoral nerve blockade a definitive anesthetic?
49. How is femoral nerve blockade achieved? What volume of local anesthetic should be deposited for femoral nerve blockade?
50. What nerve forms the saphenous nerve?
51. How is blockade of the saphenous nerve performed at the level of the thigh?
52. Where along the course of the sciatic nerve is the popliteal nerve block performed? What surgical sites are best covered by this block?
53. What supplemental blocks may need to be combined with popliteal nerve blockade?
54. What are the five nerves that supply the foot? What areas do each supply?
55. How is an ankle block achieved? What is the total volume of local anesthetic that is typically deposited in an ankle block?
Intravenous regional neural anesthesia
56. For what procedure types is intravenous regional neural anesthesia (Bier block) commonly used?
57. What are some contraindications for intravenous regional anesthesia?
58. How is a Bier block achieved? What volume of local anesthetic is used in a Bier block?
59. What local anesthetics are typically used for a Bier block?
60. What are some advantages of a Bier block?
61. What are some disadvantages of a Bier block?
62. What is a potential complication of a Bier block? How can this risk be minimized?
Answers*
1. Types of peripheral nerve blocks include blocks of the cervical plexus, brachial plexus, median nerve, ulnar nerve, radial nerve, sciatic nerve, femoral nerve, saphenous nerve, and ankle block. (285)
2. In addition to surgical anesthesia, peripheral nerve blocks may be used for postoperative analgesia and for the diagnosis and management of chronic pain syndromes. (284)
3. Considerations that should be made in the preoperative evaluation of a patient who is to undergo a peripheral nerve block include the patient’s coagulation status, the presence of any neuropathy in the involved nerves, the presence of any skin infection overlying the area where the needle will be inserted, and the presence of any anatomic abnormalities or difficulties with the usual landmarks for the performance of the nerve block. In addition, the patient should be evaluated in the usual manner with regard to history, physical examination, and laboratory analysis. The anesthesiologist must be prepared to administer another anesthetic in the event that the peripheral nerve block is not sufficient for surgical anesthesia and the surgery must proceed. (284-285)
