Minimally Invasive Surgery of Right Superior Liver Segments Safe and Effective

MSK HPB surgeons

Minimally invasive surgery (MIS) to resect liver segments 7 and 8 is safe for select patients treated by experienced MIS hepatopancreatobiliary surgeons, according to our retrospective study published recently in the Journal of Surgical Oncology(1)

Whether MIS is a safe and reasonable alternative to an open approach for resection of segments 7 and 8 has been controversial, given their anatomic location and associated technical difficulties controlling bleeding. Many surgeons consider MIS resection in these segments as challenging as major hepatectomies. (2), (3)(4) As a result, a majority have been performed with an open approach.

However, an abundance of literature has suggested that hepatopancreatobiliary surgeons with MIS expertise can successfully resect any liver segment in carefully selected patients. (5), (6), (7), (8), (9), (10), (11), (12) Studies have found that compared to open surgeries, MIS results in decreased length of hospital stay, postoperative pain, blood loss, and wound complications, with no difference in oncologic outcomes. (6), (13), (14), (15)

Previous reports have also described the safety of resecting segments 7 and 8. However, they drew conclusions on smaller cohorts than our present study, and some included segments 1, 4a, 7, and 8, making it difficult to tease out findings for segments 7 and 8 alone. (16), (17), (18) As a result, they did not sufficiently answer whether MIS resections of segments 7 and 8 are safe and feasible.

Our study is one of the few multi-institutional studies focusing on resection of segments 7 and 8 with a sample size of more than 200 patients with a broad range of tumor pathologies. We analyzed outcomes for 245 patients who underwent MIS or open liver resections of lesions in segments 7 and 8 at two high volume specialty centers — Memorial Sloan Kettering Cancer Center and Singapore General Hospital between 2003 and 2016. Thirty percent of patients (73) received MIS, and 70 percent (172) had open surgical resections. (1)

Our study is one of the few multi-institutional studies focusing on resection of segments 7 and 8 with a sample size of more than 200 patients with a broad range of tumor pathologies.
T. Peter Kingham Director of Global Cancer Disparity Initiatives

Compared to the open surgery group, patients in the MIS group experienced a 20 percent longer operative time, 35 percent lower blood loss. Our results also show that the mean length of hospital stay was three days shorter in the MIS group when compared with the Open group. There were no significant differences between groups in Pringle time, rates of postoperative complications, or tumor surgical margin. The latter variable is a well-established surrogate of oncologic outcomes. (1)

Our findings highlight the safety and benefits of the MIS approach for resections of liver segments 7 and 8 in select patients when performed by experienced surgeons at high-volume centers. At MSK, seven board-certified surgeons on the Hepatopancreatobiliary Service perform about 800 to 1,000 procedures annually. Whether surgery is required and best performed with MIS or an open approach is determined on an individual patient basis. Our surgical team meets weekly, together with specialists from a variety of disciplines — including medical oncologists, surgeons, radiation oncologists, radiologists, gastroenterologists, and pathologists — to discuss complex cases, weigh the risks and benefits of different treatment alternatives, and determine the best course of action for each patient.

MIS for Liver Resections

The prevalence of MIS for liver resections, which includes laparoscopic and robotic procedures, is increasing worldwide. (19) MIS has been used to treat patients with benign and malignant lesions, and higher-risk patients with cirrhosis and portal hypertension. (13) Starting in 2008 and updated and expanded in 2014, an international group of experts, including two from MSK, concluded that laparoscopic surgery is safe when conducted by experienced MIS hepatobiliary surgeons. (5), (6)

The introduction of robotic platforms with 3-D, high-definition, and magnified visualization has facilitated a broader implementation of MIS. Additional advances in technical modifications, such as patient positioning techniques, the caudal approach, and placement of intercostal ports, have helped address the challenges of using MIS approaches for complex liver resections. (20), (21), (22)

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Study Design

We analyzed data for 245 patients who underwent MIS or open resections of lesions in segment 7 or 8 between 2003 and 2016 at MSK or SGH. MIS included complete laparoscopic or robotic approaches without the use of a hand port. Patients who underwent conversion from MIS to open surgery were analyzed within the MIS group.

We examined demographic information, preoperative clinical characteristics, intraoperative variables (operative time, Pringle time, and blood loss), length of stay, and 30-day postoperative morbidity and mortality data. Patient information included age, gender, body mass index (BMI), tumor histology, tumor surgical margin, tumor size, and history of prior abdominal surgery. Complications were identified as any Clavien-Dindo grade I-V complication. (23)

Patient selection for MIS was at the discretion of surgeons, and their decision-making varied. For some surgeons in the study, the only contraindication for MIS was the need for vascular reconstruction or involvement. Others only approached tumors in segments 7 or 8 if the lesions were superficial, using an open approach for larger tumors. Surgeons in the study performed the liver dissections with equipment from a range of different suppliers.

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Study Results

Patient Characteristics

Among 245 patients, 172 (70 percent) had open surgery, and 73 (30 percent) received MIS. Of the MIS cases, a total of 15 (21 percent) received robotic surgeries. Since this study was completed the majority of these cases are now performed with the robotic platform. Ten patients underwent conversion from MIS to an open approach due to bleeding, proximity to vessels, inadequate margin assessment, and no clearly identifiable lesion on imaging. These patients were included in the MIS analysis. (1)

There were no differences in age, gender, or BMI between the MIS and open groups. There was a difference in the distribution of histologies between the MIS and open groups, with the most common lesions as follows: colorectal metastases (44 vs. 45 percent) followed by primary liver or bile duct cancers (32 vs. 43 percent), benign lesions (16 vs. 5 percent), and other metastases (8 vs. 7 percent), respectively. (1)

Rates of R0 and R1 resections were similar between groups, and the rate of prior abdominal surgeries was the same. The mean tumor size for the entire cohort was 3.3 ± 2.5 cm, but patients in the MIS group had significantly smaller tumors (2.7 ± 1.6 cm) than patients in the open group (3.5 ± 2.8, p = 0.01). (1)

Surgical Outcomes

Compared to the open group, operations in the MIS group were about 20 percent longer. Patients in the MIS group also experienced a 35 percent lower blood loss, and their length of stay in hospital was 39 percent shorter. There were no significant differences in Pringle time, rates of postoperative complications, or R0 resections between the MIS and open surgery groups. Refer to Table 1 for detailed findings: (1)

Table 1 Comparison of Outcomes for MIS vs. Open Surgery Groups



N = 73 (30%)


N = 172 (70%)

P value

Mean operative time, minutes (SD*)

222.7 (87.7)

188.3 (71.8)

< 0.01

Mean blood loss, mL (SD)

296.7 (287)

447.7 (699.5)


Mean length of stay, days (SD)

5.2 (7.4)

8.3 (11.7)

< 0.001

Pringle time, minutes (SD)

15.5 (26.7)

21.0 (22.2)


Complication rate, N (%)

7 (9.7)

26 (15.1)


*SD = standard deviation

In the MIS group, seven patients experienced 12 unique complications. In the open group, 26 patients experienced a broader range of 34 unique complications, which were primarily related to gastrointestinal and genitourinary issues. (1)

Interestingly, all conversions from MIS to open surgeries occurred in the laparoscopic subgroup. However, whether the robotic platform conferred an advantage over laparoscopy for these challenging procedures was beyond the purview of our study and merits further investigation.

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Advancing Outcomes for Patients with Liver Cancer

We are committed to finding new ways to reduce the effects of cancer treatments on patients while improving or maintaining oncologic outcomes. This study demonstrates that minimally invasive approaches can be used to resect even the hardest segments of the liver.

In addition, to our focus on advancing minimally invasive liver surgery, MSK also has ten liver cancer clinical trials actively enrolling new patients. These studies are testing new treatment approaches, including novel drugs, immunotherapies, and surgical advances. For example, our Phase I/II Study Evaluating Hepatic Embolization with Bumetanide to Treat Inoperable Liver Cancer is testing whether adding the diuretic bumetanide makes transarterial embolization (TAE), a common treatment for people with liver cancer who cannot have surgery, more effective in inhibiting tumor growth.

All study authors declared no competing interests.

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