Harmonic dissection yielded better outcomes compared to electrocautery with lower estimated blood loss ( 100 62 vs. 182 92 , p < 0.001 ) , less drain volume ( 631 275 ml vs. 1035 413 ml , p < 0.001 ) , fewer drain days ( 12 3 vs. 17 4 , p < 0.001 ) , less seroma formation ( 21.3 vs. 33.3 % , p = 0.071 ) , and less postoperative pain [ median ( interquartile range ) 2 ( 2-2 ) vs. 3 ( 3-4 ) , p < 0.001 ] , whereas mean operative time ( 191 44 vs. 187 36 min , p = 0.49 ) and SSI ( 0 vs. 4 % , p = 0.122 ) did not differ .