Laparoscopic liver resection in the semiprone position for tumors in the anterosuperior and posterior segments, using a novel dual-handling technique and bipolar irrigation system

The indications for laparoscopic liver resection are given in Table 1. The majority of liver tumors in both groups were hepatocellular carcinoma (HCC).

The preoperative characteristics of the patients are listed in Table 2. Mean patient age, sex, body mass index, history of laparotomy, and preoperative chemotherapy were similar between the two groups. Most patients had underlying liver disease due to hepatitis B or C virus infection or preoperative chemotherapy: 26 patients (33.8 %) had chronic hepatitis, 20 (26.3 %) had liver cirrhosis, and 23 (30.3 %) had received preoperative chemotherapy. Only one patient had Child-Pugh class B liver function, and none had Child-Pugh class C liver function. The preoperative indocyanine green retention rate at 15 min was similar in both groups.

Tumor characteristics are given in Table 3. There were no significant differences in mean tumor size, number of tumors, or location of tumors (surface or deep) between the two groups.

The types of liver resection performed are listed in Table 4. The proportions of patients who underwent major resection were not significantly different between the two groups. In patients who underwent minor liver resection, anatomical resections such as S6 and S7 segmentectomy were performed only in the semiprone group (P < 0.05). The proportion of nonanatomical resections of S1, S7, and S8 was also significantly higher in the semiprone group than in the supine group (P < 0.01).

Intraoperative and postoperative outcomes are given in Table 5. There were no conversions to open surgery in either group. Of the 24 patients with metastatic colorectal cancer, 12 had undergone previous resection of the primary tumor, and 12 underwent simultaneous laparoscopic resection of the primary tumor by low anterior resection (n = 5), sigmoid colectomy (n = 3), or right colectomy (n = 1). One patient in the supine group underwent simultaneous laparoscopic distal gastrectomy for early gastric cancer, which was detected during the preoperative investigation of HCC.

The mean operating time was not significantly different between the semiprone and supine groups. There was less blood loss in the semiprone group (mean 158 g; range 580–1,070 g) than in the supine group (mean 889 g; range 120–3,200 g) (P < 0.05), and this difference was greater when patients who underwent simultaneous colorectal or gastric resection were excluded. The mean postoperative hospital stay was shorter in the semiprone group (median 11 days; range 5–23 days) than in the supine group (median 35 days; range 7–71 days) (P < 0.05), and this difference was also greater when patients who underwent simultaneous colorectal or gastric resection were excluded.

Six patients (8.6 %) developed postoperative complications, and the complication rate was similar between the two groups. Bile leakage at the cut surface of the remnant liver occurred in one patient with HCC in the supine group. Postoperative symptomatic intra-abdominal fluid collection occurred in one patient with HCC who developed prolonged ascites after minor liver resection, which resolved after administration of diuretics and limitation of water and salt intake. Intra-abdominal abscesses requiring treatment occurred in four patients who underwent simultaneous colorectal resection. In one of these cases, the abscess was adjacent to the partial resection of S8 and was managed by percutaneous drainage and right colectomy. The other patients had undergone low anterior resection, and the abscesses were adjacent to the bowel anastomoses or in the right lower abdomen. No patients required reoperation, and there were no cases of gas embolism, major complication, or perioperative death.

The results of pathological examinations of the surgical specimens are given in Table 6. There were no significant differences between the two groups in tumor-free margin, minimum distance from resection line to tumor tissue, or weight of resected specimens.

Laparoscopic liver resection in the semiprone position has a number of advantages over that in the supine position. First, Rouviere’s sulcus [16, 17], a fissure on the liver to the right of the hilum, is easily visualized immediately after insertion of the laparoscope. This sulcus is open in 78 % of patients and is recognizable in more than 90 % [18]. The liver stays in position because it is attached to the coronary and right triangular ligaments, but other organs such as the transverse colon and small intestine fall to the lower left. The right hepatic hilum is therefore easily exposed by lifting the edge of the liver or gallbladder. The portal pedicles of the anterior and posterior segments and the segmental pedicles of S6 and S7 can easily be ligated for selective occlusion of the blood supply prior to parenchymal transection.

Second, an intercostal port can be used effectively in the semiprone position. When parenchymal transection is performed using only subcostal ports, transection can be performed from only one direction because the forceps cannot reach the portions of the posterosuperior and anterosuperior segments located adjacent to the diaphragm (Fig. 3). Although it is possible to visualize these areas using a flexible scope or a 30° or 45° laparoscope, it is nearly impossible to operate in this area using only subcostal ports. Partial resection of a posterosuperior or anterosuperior tumor is therefore more difficult than hemihepatectomy or sectionectomy. Right hemihepatectomy involves a relatively small dissection plane and can be performed by approaching the liver from the inferior side at the hepatic hilum, from the front of the IVC. An intercostal port gives access to the abdominal cavity from the seventh intercostal space in the anterior axillary line, passing through the thorax and the diaphragm. This port can be used by the right hand of the operator, allowing the surgeon to approach the liver from both the inferior and the superior aspect to perform partial resection or segmentectomy of S7 and S8. Gayet and co-author [19] used an intercostal port to retract the hepatic veins from a lateral approach. However, as the port was on the left side and the patient was in the supine position, this port could not be used for parenchymal division. The technique they described is clearly different to our procedure [20].

Third, the weight of the liver helps to mobilize it. When the coronary and right triangular ligaments are transected, the right lobe naturally falls to the left, leaving a space under the right side of the diaphragm. This is one of the reasons that an intercostal port can be used and enables division of the blood vessels around the IVC without elevation of the liver by an assistant.

Fourth, the irrigation fluids and blood flow to the lower left side of the abdominal cavity and do not interfere with visualization of the operative field [14, 15].

There was less intraoperative bleeding in the semiprone group than in the supine group for several reasons. The semiprone position enables selective vascular occlusion before parenchymal transection, and the posterior segment is positioned higher than the IVC. We also used an innovative device that had a channel for dripping saline at the tip of a surgical instrument. This device can be attached to various endoscopic bipolar scissors or forceps, including bipolar forceps that can be precisely controlled such as the BiClamp, BiCision, and LigaSure. This equipment is used by some liver surgeons for careful hepatectomy via laparotomy, such as harvesting of a living-donor transplant [21, 22]. However, use of this device in laparoscopic surgery has not been well developed. The saline-dripping channel contains compressed saline or is attached to an infusion pump, and the flow rate can be adjusted from a slow drip to a water jet. Saline dripping prevents adhesion of tissues to the cautery blades by reducing the contact between the electrodes and the tissues, and it washes the blood away. This enables fine parenchymal dissection and careful identification and exposure of the portal pedicles. ENSEAL^® (Ethicon Endo-Surgery, Cincinnati, OH) is another modern bipolar device that can coagulate tissues by contact with only one of the jaws [23‐25]. This jaw can be used to thinly scoop a portion of hepatic parenchyma before picking up the scooped parenchyma with both jaws and then coagulating and cutting it.

The most common indication for laparoscopic liver resection is HCC in patients with underlying liver disease [7]. Resection of metastatic liver cancer is performed with increasing frequency, but many patients with metastatic cancer have liver damage due to previous chemotherapy [26]. If a sufficient surgical margin can be achieved, partial segmental resection is preferable to segmental resection, and segmental resection is preferable to lobectomy.

The use of innovative techniques and devices enables selective hepatic vascular occlusion and parenchymal division in the semiprone position. This allows us to perform partial resection and anatomical resection of the posterosuperior segments of the right liver with minimal bleeding and ischemic injury.

The semiprone position has some inherent disadvantages. When the laparoscope is initially introduced into the abdominal cavity, the positions and relationships of structures are unfamiliar. Rotation of the camera can help to achieve a more familiar orientation. It is important for surgeons learning this technique to familiarize themselves with the visual field and the locations of organs in this position. For tumors of the hepatic dome, resection is performed from the lower aspect to the upper aspect, even when using an intercostal port. Even if the operator is right-handed, parenchymal dissection should be performed mainly using the left hand while supporting the portion of the liver containing the tumor using the right hand.

We experienced one case of the tracheal tube becoming dislodged. Fortunately, this did not have serious consequences because the anesthesiologist responded immediately. Care must be taken to avoid blindness due to prolonged pressure on the eye, as has been reported in patients who underwent esophagectomy in the prone position.

Three surgeons are now performing hepatectomy in the semiprone position at our institution, and the indications for pure laparoscopic hepatectomy have expanded rapidly since the introduction of this technique. The technique is also being used at a number of other institutions in Japan. We believe that use of this technique has resulted in expansion of the indications for laparoscopic resection of tumors in the anterosuperior and posterior segments and has improved outcomes, irrespective of number of surgical experience of surgeon.

In conclusion, introduction of the semiprone position allowed us to perform laparoscopic liver resection in patients with tumors of the anterosuperior and posterior segments, without increasing the proportion of patients undergoing major hepatectomy. This method is safe and minimally invasive and can reduce intraoperative bleeding and shorten the postoperative hospital stay compared with resection in the supine position.