What is the difference between time period of the claim while approved and the time period of the claim while denied?

I had a total hip replacement surgery that was delayed pending a dental clearance, which took a couple months. The first notice of claim denial came the day before surgery and was only the first of many to come. The claim was approved for a short period of time. The surgery had some complications from a staph infection that set healing process back delaying the physical therapy program. My question is what is difference between time period of claim while approved and time period of claim while denied as I received nothing from either time period until today when I got a check in the amount of $11.94,gross and after taxes was $8.02, under the heading of "short term disability".