Pins and needles is not a medical condition. Your leg going numb is completly safe as long as you limit your sitting meditation to one hour. It will stop being a hindrance once you get into samadhi.
Your attachment (and fear) about your body is getting in the way. I hope you overcome them. In the suttas there is talk of sitting fearlessly:
"That monk, your majesty,
on the flank of Pandava,
sits like a tiger, a bull,
a lion in a mountain cleft."
Later the monk (the Buddha) is offered a place in the arm:
"You are young, youthful,
in the first stage of youth,
endowed with the stature & coloring
of a noble-warrior.
You would look glorious
in the vanguard of an army,
arrayed with an elephant squadron.
Now, here is a good teaching. We sit like a warrior going into battle, not like a weakling complaining of the slightest strain.
I wish you well