This is about as bad a chart as it gets.
It is a case example of what not to do when electing a time for surgery.
Anyway, keep in mind the Lord of the Hour. The Lord of the Hour, or planet ruling the Hour, isn't anywhere on astro.com by the way. And when you're really good at electing charts, one will keep in mind the Term of the Ascendant. I don't think we're to that point, however, in our level of electing charts.
The Moon, is separating from its ruler, Mars. This isn't too bad, because it show the event is already over, because its separating.
Having the Ascendant in Cancer, the detriment of Mars, is not a good start, especially if the surgery is on the breasts or stomach. 4 planets in detriment/fall is not good to say the least, especially the Lord of the Ascendant. There is a negative relationship between the Sun and the Moon (they are disjunct) indicating an inability to heal.
Nor the Sun in the 12th, applying to Saturn who rules the 8th, the house of death. The ruler of the 6th is found in the 8th house. Wow.
I'm not saying you're going to die. But I wouldn't have surgery this day at this time. Change it. You don't realize how bad this is. The Moon is also Via Combust. Forget the idea of Void of Course, I'd rather have a Void of Course Moon in Taurus, Cancer, Sagittarius or Pisces, than this one, on any day!
You've also got the ruler of the 12th, applying to the ruler of the 6th, who is in the 8th house. Call the morgue!
Venus and Mars are not really in reception, because planets that are in detriment do not have the power to receive each other, and they are not even aspecting each other. They are also out of Sect, and are extremely powerless.
Study a few more books, the rules for surgery aren't too hard to understand. It is as though this chart intentionally has broken all the rules.
The part of the body being operated on is perhaps the greatest consideration, and you've made no mention of it. Yes, surgery should be done when the Moon is near empty, for less blood loss.
Now, since this surgery isn't a big deal, I wouldn't worry. But I wouldn't have brain surgery during this time unless I wanted someone to die. You and your body are fine because the surgery is minor. No worries.
~hugs~
Joseph