I had similar situation end of last year. Minor op on lower back. Couldn't pullup or hang for 2-3 weeks at risk of splitting stitches. Found I could lift some pretty heavy weights with basic 15mm-20mm crimp setup like Duncans link. Weights on floor between legs, single hand lift, straight / vertical back and lift with the legs didn't seem to activate the lower back or strain the wound in the slightest.