Obstruction 4.5 years post take-down?

Adhesions tend to form fairly early after surgery. Some of them are located such that they cause problems frequently, and some are located such that they cause problems infrequently (most never cause significant problems). I'd guess that one of the infrequent-problem sort gave you trouble last night. Vomiting can be a sign that things have taken a turn for the worse. I'm glad it cleared up fairly quickly and didn't necessitate a trip to the hospital!

As someone who has had an unfortunate number of blockages (assuming most of them due to adhesions since I recently had 8 bands of adhesions removed), mine did not start until 3 years after takedown.  I've had them chronically the last couple years.  Each of my blockage presented themselves differently.  With all of the ones resulting in vomiting, I ended up in the hospital.  I've had instances similar to yours (without the vomiting), but I honestly think it was more backup/constipation in my case.  I was actually back in the hospital again this week with what I thought was a partial obstruction, but it ended up being 5 days of severe diarrhea that we could not find a cause for.  

Adhesions may form early on, but they can stiffen or toughen over time, leading to obstructions. Scar tissue can also lead to kinks and twists in the bowel, and of course stenosis (or narrowing) and stricture can also occur over time. Again, all of these things can contribute to blockages. I had several partial obstructions last year, although I was 6 years post takedown. Prior to that, I didn't have any issues.  I typically will go to the hospital if I'm vomiting or in severe pain, or if the obstruction doesn't start to pass after about 12 hours. Thankfully I've been able to ride most of them out. I don't find the ER particularly helpful in any case, but I will go if I'm in distress. For me, adhesions and scar tissue around the old stoma site have been the culprit. I've made some modifications to my diet, which seems to have helped. I prefer to manage things conservatively and will only do surgery again as a last resort.

It sounds like a partial or total obstruction to me.  I have partial ones and rarely throw-up.  That's why I am guessing yours was a total obstruction.  If I were you I'd stay on soft foods for longer than a day or two.  Things get swollen inside during these "episodes".  

My surgeon told me I would have them from time to time and basically to live with them after he ordered a small bowel study. It's the test you drink barium on a empty stomach for. They x-ray your abdomen to look for kinks, blockages, narrowing etc, in your intestines. I didn't have anything like that but it took hours for the barium (water) to make it through to my j-pouch the last test I had.  I'd had one a year before that took a lot less time.  2.5 hours compared to 30 minutes, that is why I think your irritated area might be swollen for a while. 

I have a lot of adhesions but they don't operate unless they cause major problems.  Each time they open you up they add more scaring so having a surgery in it's self could make the problems worse.