This is a letter to a doctor. Your patient Bob Smith underwent liver transplantation earlier this month. OR Your patient, Bob Smith, underwent liver transplantation earlier this month. Thanks.....
The second one is correct, because the name is in parenthesis. Basically, it's the same as putting it in brackets. You could remove it, and the sentence would still work just as well.
Either is correct, but the meanings are subtly different. The first, without the commas, asserts that the name Bob Smith is necessary information. Bob Smith -- who was one of your patients -- underwent a liver transplant. The second emphasizes that it was one of your patients -- Bob Smith, in case you are interested -- underwent a liver transplant. See the difference?
When read aloud.... The sentence with the commas sounds to me like Bob Smith is the sole patient of the doctor the letter is being written to. For example, if you have two sons, Mark and John, I would say to you "Your son Mark is mowing the lawn." If you had one son named Mark, I would say "Your son, Mark, is mowing the lawn." Does my reasoning for no commas make sense? I'm so confused... LOL
No. The commas simply set off a parenthetical phrase, which mean a modifier not essential to the meaning of the sentence. The person being spoken to may have hundreds of patients. Making the name parenthetical simply reduces the emphasis on which patient has a new liver. Without the commas, the subject is Bob Smith (who is one of your patients). With the commas, the subject is your patient (the one named Bob Smith). It does not imply he is your only patient. Your son, Mark, is mowing the lawn. The other one is out swilling beer with his friends. (John is flirting with being disowned at the moment. The emphasis in the sentence is on "Your son". Which one? Mark, if you have to even ask!)
