Quantitative and Technical Material

Chapter 12, Questions 1-6

1. a. When the electrode is fully in the spinal cod tissue, the resistance shoots up to 1,000 Ω or more.

b. There are two methods of applying a coagulating current. One uses a fixed time (e.g. 30 s), and varies the power applied (e.g. 5 mA, then 15 mA, etc.), up to a limit given by the manufacturer. The other method fixes the power (e.g. at 30 mA), and varies the time (e.g. 5 s, then 10 s, 15 s, etc.).

         Query: What is the unit mA? Please double check that capitalization and spacing are correct.

c. The spinal cord at the C1-C2 level is about 15 mm across and 10 to 12 mm from front to back, so the maximum lesion needed is 6 x 4 mm. Furthermore, a cylindrical electrode with a 2 mm uninsulated tip will provide a lesion somewhatbarrel shaped; an exposed tip of 3 mm is also used and will proved a lesion of about 4.5 x 3 mm.

2.   

3. a. 1/16

    b. 3/(a + b)

    c. (x + 2)/2y

4-6.