Coinsurance for Surgery

Hi y’all,

I truly need someone to explain coinsurance to me like I’m five.

I am having an SI joint fusion done on 9/28, and I’m not really clear on what to expect in terms of my OOP costs. For reference, I’ve got United Healthcare with an $800 deductible (already met) and 10% coinsurance ($1900ish remaining out of $3900 OPM). My plan is through my employer.

The surgery itself is most likely going to cost between $30-$40k, and I’m not sure how to calculate what I’ll need to pay up front, if anything. I’m anticipating around $400 but I know it could very well be my remaining $1900.

If it helps at all, I recently had bilateral ESIs done with a final bill of around $5.8k, and all I had to pay was $72 at the time of service. I also paid $72 for bilateral SI joint injections that were $1.7k total. I can’t figure out why both procedures only cost $72 considering the vast difference in price, or if $72 is even relevant in the grand scheme. Also, I had both of these procedures done AFTER I hit my deductible.

Any insight would be much appreciated!