I sort of have the opposite issue as everyone else. I would actually like to serve on a jury, but it will never happen. First of all, because I am a trial attorney and all the Judges and attorneys in my area know me or my firm. And second, because litigation attorneys tend never to be picked as jurors on the theory that everyone else on the panel will defer to and follow their lead, turning a jury of 12 or 6 into a jury of 1.
A funny story developed the last time I got called for jury duty in Connecticut. The way it works in the state courts in Connecticut (and jury selection is much different in the federal courts), is that perhaps 75 persons are called and they are asked to wait in a giant room that is equipped with TV, WiFi, and (yes!) bathrooms. The wait could be up to hours as the Judge and attorneys have what is called a trial management conference, at which the Civil Presiding Judge attempts to mediate the case and see if a settlement can get brokered. If not, jury selection starts. At the beginning you are asked to fill out a questionnaire collecting some basic information which the attorneys will have when they question you as part of the process which is called Voire Dire.
Every judge handles the initial screening process differently, but usually what the Judge will do is call a large group of potential jurors into the courtroom from the juror waiting room. The attorneys in the case are also present in the courtroom with their clients. They will introduce their clients and themselves, and identify by name the staffs of their firms. The Judge will then ask the jurors questions about possible conflicts and ask the jurors to only raise their hands and NOT to verbalize or shout out (so the other jurors can hear) what the conflicts are. The questions involve work or medical hardships, knowing someone who is a party in the case, a witness, or one of the attorneys involved in the case.
Usually the last question the Judge asks is a generic "catch-all" question, along the lines of "can you think of any other reason why you cannot serve as a fair and impartial juror on this case based on what you have heard so far?" The people who raise their hands in response to one or more of the questions get called in first.
When these questions were asked, I did not raise my hand in response to any of them, although I knew very well and went to law school with one of the attorneys at the firm representing the defendant (who was not one of the trial attorneys), and used to work with one of the partners at the firm representing the plaintiff, although he was not one of the trial attorneys. Both firms are small firms and I pretty much knew a great deal of the staff at both places, just from past cases.
So after the Judge gets through canvassing the entire pool, individual jurors are then brought in one by one, the people raising their hands first, and then the others. When I finally get called in, the Civil Presiding Judge, whom I have known for many years, looked at me with a big smile on her face. She said to me, "Attorney _________, I did not see your hand go up in response to any of my questions. Why is that? Aren't you a defense attorney who works for insurance companies????????????????" The truth is that the Judge had only seen me in the past in cases in which I was a defense attorney, but that is not all that I do, and about 20% of my practice is plaintiff's work representing injured persons.
So I said, "Judge, it's true that I do defense work, but I also do a smaller amount of plaintiff's work. It's also true that I worked with _____________ at the plaintiff's firm and went to law school with ___________________ at the defendant's firm. But I know the staffs at both firms well and I would like to think that I can be fair and impartial to their clients in this case. In the future I would actually like to do some work as a private mediator or arbitrator."
So the Judge looks at me and with a big smile she says, "well maybe we should stop picking a jury right now and just have you mediate the case to a resolution?" At that point the attorneys and their clients all started laughing.
After that, before the attorneys said anything or asked me a single question, the Judge looked at me with a grin and said, "Attorney_________________, I do not think you would be a good choice as juror on this case. You can go home now." And so I left. The Judges do have the power to kick you out for any reason they deem appropriate. In a case in which I was representing a Vietnamese woman, I got a Vietnam Veteran kicked off the jury when I asked him if he had any problem with Vietnamese people as a result of his war experiences and he answered, "only the ones who were shooting at me." The Judge said, and I do quote, "get him out of here."
Regarding my own inflamed pouch affecting me during trials, I have in the past alerted trial judges to the possible issue of bathroom use but it has never actually become an issue. I think adrenaline somehow treats the pouch in ways I cannot explain. In your case, I would not suggest you get a report from your Doctor concluding you cannot serve (which to me has the appearance of self serving nonsense), but rather just setting forth the facts of your condition, possible anticipated interruptions etc. and let the Judge make a decision based on the medical facts. Judges having such information will then ask you if your medical condition will likely prevent you from being able to sit and listen to all the evidence and you then give your honest answer to that question. Judges are not interested in the selection of jurors who will become a major distraction.
After your jury service is completed, you will be sent a voucher of service. Make sure to save this voucher, as by law in most jurisdictions, you cannot be called more than once in a designated period of time which may be 2, 3 or 5 years.