1.2.254 Kidney Stone Treatment A study94 collected data comparing treatments for kidney stones. Two of the treatments studied were open surgery and percutaneous nephrolithotomy. Treatment was deemed "successful" if, after three months, the kidney stones were either eliminated or less than 2 mm. The latter treatment (nephrolithotomy) is cheaper and less invasive, but is it as successful? Results are shown in Figure 2.97, first overall and then broken down by stone size. (If the answers are not obvious visually, in each case you can calculate the proportion of successes using the numbers shown on the graph.)

In order to answer the questions below make sure you show work with proportions and the notation

P(A), P(B), and P(A | B) (see Blackboard).

When all stone sizes are considered, which treatment is more successful?

When all type of kidney stone is considered Percutaneous nephrolithotomy treatment is more successful while in case of small kidney stone open surgery is more successful.

In case of all type of kidney stone Success rate of Percutaneous nephrolithotomy treatment is higher than success rate of open surgery success rate of Percutaneous nephrolithotomy treatment {P(A) = 289/(289 + 61) = 289/350 = 0.8257}. The success rate of open surgery is {P(B) = 273/(273+77) = 273/350 = 0.78}. Therefore,>P(A)>P(B).

So, In case of all type of kidney stone Percutaneous nephrolithotomy treatment is more successful as compare to open surgery treatment.

When only small kidney stones are considered, which treatment is more successful?

Similarly, in case of small kidney stone success rate of open surgery treatment is higher than success rate of Percutaneous nephrolithotomy treatment.

The success rate of Percutaneous nephrolithotomy treatment is {P(A) = 234/(234 + 36) = 234/270 = 0.8667} and the success rate of open surgery is {P(B) = 81/(81+6) = 81/87 = 0.931}. Therefore,>P(B)>P(A).

So, In case of small kidney stone open surgery treatment is more successful as compare to Percutaneous nephrolithotomy treatment.

When only large kidney stones are considered, which treatment is more successful?

Which stone size results in higher success rates, regardless of treatment type?

Which treatment is more commonly used for small stones?

Which treatment is more commonly used for large stones?