Electrocautery Promotes Colonization of Mrsa Inoculum in Rabbits After Open Ventral Hernia Mesh Repair

Fernando Cabrera, MD1, Joseph Fernandez-Moure, MD, MS2, Azim Karim, MD1, Jeffrey Van Eps, MD2, Ennio Tasciotti, PhD3, Bradley Weiner, MD2, Brian J Dunkin, MD, FACS4. 1Houston Methodist Research Institute, Surgical Advanced Technology Laboratory, 2Houston Methodist Hospital, Houston Methodist Research Institute, Surgical Advanced Technology Lab., 3Houston Methodist Research Institute, Department of Nanomedicine, 4Houston Methodist Hospital, Methodist Institute For Technology, Innovation and Education (MITIE)

Monopolar electrocautery has been widely used across multiple surgical disciplines because of ease of use, effective hemostasis and surgical dissection. Studies have demonstrated its use to be an independent risk factor for postoperative wound infection. Compared to scalpel use alone, previous studies have shown the use of electrocautery is associated with decreased wound tensile strength and more frequent bacteremia after midline laparotomy. However, in the presence of underlying prosthetic material for inguinal hernioplasty, previous reports have shown infectious complications and wound healing unchanged regardless of electrocautery use. Methicillin resistant Staphylococcus aureus (MRSA) is the most common bacteria found in postoperative mesh infection. No reports are available on the sequelae of electrocautery use for open ventral hernia repair (VHR). Therefore, we sought to determine infectious complications of electrocautery use following VHR with a polyester multifilament composite mesh. We hypothesized that compared to use of scalpel alone, electrocautery use will result in higher infectious burden after implantation of prosthetic mesh for open VHR.

Methods: New Zealand Rabbits undergoing open VHR with polyester mesh were divided into three groups: scalpel alone (Group 1), and discriminant (Group 2) versus indiscriminant (Group 3) electrocautery use, respectively. After a 5cm midline abdominal incision through the fascia and linea alba, a composite polyester mesh was placed in an underlay fashion and fixated with interrupted Prolene™ sutures. Once in place, the mesh was inoculated with 1×105 of MRSA and the skin closed in a subcuticular fashion. Rabbits were followed postoperatively for 7 days with daily physical exam, vital signs, complete blood count, basic metabolic panel and blood cultures on post-operative day (POD) one and seven. On POD 7, surviving rabbits were sacrificed and the meshes were explanted for MRSA colony forming unit (CFU) quantification.

Results: After 24 hours, all Group 3 rabbits developed fevers greater than 105°F, their wounds displayed significant warmth, erythema, and circumferential skin eschar compared to other groups (Figure 1), and these subjects were euthanized due to severity of illness as determined by veterinary staff. In the scalpel alone group, swelling, redness, or warmth around the affected area was minimal (Figure 1) and vital signs were stable. Whereas in the discriminant use of electrocautery group, erythema and swelling of the area were noticeable but no febrile episodes were recorded. During mesh explantation, collection of purulent discharge was noted in Groups 2 & 3, but not in the scalpel alone group. After 7 days, the discriminant use group had an average CFU count of 2.3 x 107, meanwhile no CFUs were quantifiable in the scalpel alone group.

Conclusions: In our study, the use of electrocautery promoted the colonization and exaggerated septic response to MRSA in a dose-dependent fashion. Conversely, no use of electrocautery had a suppressive effect on colonization by MRSA. Although human data is needed, this suggests that electrocautery use should be quite limited, as it may translate to diminished surgical site/implant infections. Larger, randomized trials remain a potential source of investigation.


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