I understand better what you are talking about...could it help if you have a squirt bottle with long tip (this is easy to make...you just take a normal squirt bottle, melt the tip over a flame or in hot water (be very careful, it can burn the fingers) and then pull the plastic tip with pliers until you have stretched it to the right curve and length to get to 'that' spot without too much difficulty. It would probably need to be a bit curved. Cool it down in cold water for it to be fixed into shape. You might have to re-pierce the hole in the tip for the size of the spray.
Not sure if there is a solution to the pocket...what can or cannot be done. Is it something that happened during surgery or was it there before?
I would be loath to allow someone up there to cut and try to fix it...fear of worse damage would always be present.
The question of quality of life...Well, I know of a lot of people here on the site that 'put up with' a sh-tload of discomfort, pain or other kinds of problems for a very long time before taking the leap and finding a different solution (as I said, some opted for outside appliances, others had their J pouches redone if possible and others still found that the continent ileostomy was the best solution)....but I Do Not think that this sort of problem requires that sort of drastic measure.
I am not diminishing what you are going through but a mechanical solution is always better than a surgical one if it can be helped.
Try the squirt bottle or nozzle first (they do sell a commercial version, I believe, for enemas that may be of use to you...try it...you never know...warm water is best and much more soothing.
Let me know if it works for you...if not, I will try to think up something else.