In response to the concerns with the Nissen Fundoplication, there are some potential side effects. If your LES is only mildly incompetent, it may not be a good next step for you. The Nissen is a serious surgery. You have to chew food well for the rest of your life to keep food from getting "stuck" above the wrap. It is really unpleasant when this happens, but eventually the food does go down. Also, gas cannot come back up. This means that gas can get trapped below in the stomach resulting in Gas Bloat Syndrome. This is a syndrome specific to those who have had the NF. Another side effect I've had is some occasional intense nausea. I also have days where I feel just fine.
For those considering the NF, I would personally recommend it if their LES is really not working. It has been very helpful for me. I was having major breathing problems from acid irritating my lungs and flaring my asthma. I couldn't get my asthma under control because I couldn't get my reflux under control any more. My Manometry results showed that over the course of the last 3 years my LES functioning, which wasn't great to begin with, had gotten worse. For me the reflux had become life threatening, per my Pulmonologist. The NF was literally a life saver for me.
I hopoe someone else can respond on your SOD questions.