reading down the forum i noticed you posted the same question over and over. perhaps this is an issue you should discuss with a dentist in his office since you are obviously not getting the help you need by posting here.
you have already had the nerve removed a second will not help a fracture. i have been living with a fractured tooth that has been root canaled and crowned for over 6 years. it has some pain every once and awhile but my dentist watches it carefully and so far it has never had infection or bone loss (yet).
I believe it is nearly impossible to save a tooth that has been fractured. I lost my second molar that way.
I'm not sure why you would be advised to try another root canal if the fracture can be seen on xray. Once that happens, the tooth is usually not salvageable because it is now very brittle to begin with. A fractured tooth leaves a breeding ground for bacteria and eventual bone loss which can affect the neighboring teeth.
If you do need it removed, I highly recommend an implant to replace it. The procedure is no worse than a root canal. It just takes alot longer to get to the finished product because of healing time. My DH has 7 molar implants and loves them.
Hope this helps and I'm sorry your tooth got fractured. Root canal therapy does weaken the tooth.
My best to you,