The shelter where we adopted Angus from used what the vet called a "rip 'em & stick 'em" method. Apparently the quickly cut him open, removed his testicles and glued him back shut with super glue! The shelter admitted that's their "standard practice" after I called. Angus had kennel cough when we brought him home, but before it's determined that's what it was, my vet wanted to know if the shelter had inserted a breathing tube during the surgery thinking that may have aggravated his trachea and that could be the reason for his cough and irritation. I called and was told they don't use anything like that, just make the incision and glue them up.
Angus had a lot of swelling and irritation at the site...
When we had Mackensie spayed at our normal vet, they used stitches and she had no problem, although after she healed, the area apparently healed too tightly and she ended up with a 4 inch long chapped and raw area where the scar was. It's only since we started feeding raw that the area has healed completely and now looks good as new!