Modified Incisional Negative Pressure Wound Therapy Increases Seroma Evacuation: An Ex Vivo Model

BACKGROUND: Incisional negative wound pressure therapy (iNPWT) is a relatively novel dressing technique with the aim of reducing postoperative wound infections and dehiscence in high-risk wounds after all kinds of surgical procedures. There is a lack of theoretical knowledge about the way those dressing would ameliorate wound healing. One aspect is the reduction of superficial tension, but significant remaining seroma might still cause deep wound infections. The aim of this study was the evaluation of technical modifications of the standard iNPWT dressing to increase seroma evacuation. METHODS: iNPWT dressings were applied on the porcine abdominal wall, and an incremental pressure ramp from 50 to 200 mmHg was performed. The resulting wound pressures were measured using (i) balloon manometry and (ii) esophageal manometry catheter. Seroma evacuation was analyzed with a seroma model. All measurements were performed with (i) standard iNPWT dressing, (ii) wound gauze diverted through the incision, and (iii) placement of suction drain tube into iNPWT. RESULTS: Due to the modifications of the iNPWT dressing, the vacuum applied by the iNPWT dressing could be transferred into the wound and was not only restricted to superficial layers. More importantly, placement of wound gauzes or suction drain tubes led to complete extraction of wound seroma. The placement of the suction drain tube showed the best combination of increased intrawound pressure as well as seroma evacuation. CONCLUSION: Addition of a suction drain tube to the iNPWT dressing leads to an improved function of the iNPWT dressing in our ex vivo model.