Development of an Intracavitary Perfusion Device for Laparoscopic Hepatectomy With Water-filled Endoscopic Surgery (wafles)

Objective of the device
In recent years, the number of hospitals that perform laparoscopic-assisted hepatectomy as a less-invasive approach is increasing with development and improvement in medical devices and the advancement of surgical techniques. However, because the liver has a very rich blood supply, it is important to intraoperatively determine the hepatic vascular distribution for safe liver resection. Igarashi et al devised a water-filled endoscopic surgery (WaflES), reported in SAGES2009. A method devised by us has enabled real-time ultrasonography, by applying the WaflES; this method allows secure grasping of the lesions and vascular distribution and determination of accurate resection lines. However, it may become impossible to secure an operative field if contamination occurs due to unexpected intraoperative bleeding. Therefore, we aimed to develop a WaflES device to be placed in the intracavity for securing an operative field.

Description of the technology and method of its use or application
We created a perfusion environment for supply and drainage of artificial ascites by using a two-head roller-pump-type peristaltic pump, measured water pressure and water flow for supply, and installed a negative pressure sensor for drainage. Three 12-mm laparoscopic ports were inserted in a landrace/large white pig (weight, 41 kg) under general anesthesia, and after inducing pneumoperitoneum with carbon dioxide, about 1.5-L artificial ascites was replaced with saline (a mixture of air and liquid layers). Then, we performed the following: (1) observation of the liver by using external and laparoscopic ultrasonography; (2) external and laparoscopic ultrasound-guided resection of the liver; and (3) confirmation of hemostasis with an energy device after angiotomy.

Preliminary results
External and laparoscopic ultrasonography allows observation of the liver because the observation was mediated by saline, without contact of the laparoscope with the liver. Moreover, in liver resection, concomitant use of external and laparoscopic ultrasonography led to real-time confirmation of the hepatic blood vessels (water pressure, 0-230 mmHg; water flow, 0-1.9 L/min). For hemostasis after angiotomy, increased water flow led to securing of a critical view of satety (maximum water pressure, 300 mmHg; maximum water flow, 2.3 L/min).

Conclusions/future directions
If laparoscopic hepatectomy by using the WaflES device becomes common in the future, intraoperative external or intracavitary ultrasonography will allow navigational surgery, resulting in safe and secure liver resections.