Harmonic dissection yielded better outcomes compared to electrocautery with lower estimated blood loss ( @ @ vs. @ @ , p < @ ) , less drain volume ( @ @ ml vs. @ @ ml , p < @ ) , fewer drain days ( @ @ vs. @ @ , p < @ ) , less seroma formation ( @ vs. @ % , p = @ ) , and less postoperative pain -LSB- median ( interquartile range ) @ ( @-@ ) vs. @ ( @-@ ) , p < @ -RSB- , whereas mean operative time ( @ @ vs. @ @ min , p = @ ) and SSI ( @ vs. @ % , p = @ ) did not differ .