What Is the Current Role and What Are the Prospects of the Robotic Approach in Liver Surgery?

Robotic Versus Laparoscopic Liver Resection in Various Settings: An International Multicenter Propensity Score Matched Study of 10.075 Patients

OBJECTIVE

To compare the perioperative outcomes of robotic liver surgery (RLS) and laparoscopic liver surgery (LLS) in various settings.

BACKGROUND

Clear advantages of RLS over LLS have rarely been demonstrated, and the associated costs of robotic surgery are generally higher than those of laparoscopic surgery. Therefore, the exact role of the robotic approach in minimally invasive liver surgery remains to be defined.

METHODS

In this international retrospective cohort study, the outcomes of patients who underwent RLS and LLS for all indications between 2009 and 2021 in 34 hepatobiliary referral centers were compared. Subgroup analyses were performed to compare both approaches across several types of procedures: (1) minor resections in the anterolateral (2, 3, 4b, 5, and 6) or (2) posterosuperior segments (1, 4a, 7, 8), and (3) major resections (≥3 contiguous segments). Propensity score matching was used to mitigate the influence of selection bias. The primary outcome was textbook outcome in liver surgery (TOLS), previously defined as the absence of intraoperative incidents ≥grade 2, postoperative bile leak ≥grade B, severe morbidity, readmission, and 90-day or in-hospital mortality with the presence of an R0 resection margin in case of malignancy. The absence of a prolonged length of stay was added to define TOLS+.

RESULTS

Among the 10.075 included patients, 1.507 underwent RLS and 8.568 LLS. After propensity score matching, both groups constituted 1.505 patients. RLS was associated with higher rates of TOLS (78.3% vs 71.8%, P < 0.001) and TOLS+ (55% vs 50.4%, P = 0.026), less Pringle usage (39.1% vs 47.1%, P < 0.001), blood loss (100 vs 200 milliliters, P < 0.001), transfusions (4.9% vs 7.9%, P = 0.003), conversions (2.7% vs 8.8%, P < 0.001), overall morbidity (19.3% vs 25.7%, P < 0.001), and microscopically irradical resection margins (10.1% vs. 13.8%, P = 0.015), and shorter operative times (190 vs 210 minutes, P = 0.015). In the subgroups, RLS tended to have higher TOLS rates, compared with LLS, for minor resections in the posterosuperior segments (n = 431 per group, 75.9% vs 71.2%, P = 0.184) and major resections (n = 321 per group, 72.9% vs 67.5%, P = 0.086), although these differences did not reach statistical significance.

CONCLUSIONS

While both produce excellent outcomes, RLS might facilitate slightly higher TOLS rates than LLS.

Challenges and Opportunities for Precision Surgery for Colorectal Liver Metastases

The incidence of colorectal cancer and colorectal liver metastases (CRLM) is increasing globally due to an interaction of environmental and genetic factors. A minority of patients with CRLM have surgically resectable disease, but for those who have resection as part of multimodal therapy for their disease, long-term survival has been shown. Precision surgery-the idea of careful patient selection and targeting of surgical intervention, such that treatments shown to be proven to benefit on a population level are the optimal treatment for each individual patient-is the new paradigm of care. Key to this is the understanding of tumour molecular biology and clinically relevant mutations, such as KRAS, BRAF, and microsatellite instability (MSI), which can predict poorer overall outcomes and a poorer response to systemic therapy. The emergence of immunotherapy and hepatic artery infusion (HAI) pumps show potential to convert previously unresectable disease to resectable disease, in addition to established systemic and locoregional therapies, but the surgeon must be wary of poor-quality livers and the spectre of post-hepatectomy liver failure (PHLF). Volume modulation, a cornerstone of hepatic surgery for a generation, has been given a shot in the arm with the advent of liver venous depletion (LVD) ensuring significantly more hypertrophy of the future liver remnant (FLR). The optimal timing of liver resection for those patients with synchronous disease is yet to be truly established, but evidence would suggest that those patients requiring complex colorectal surgery and major liver resection are best served with a staged approach. In the operating room, parenchyma-preserving minimally invasive surgery (MIS) can dramatically reduce the surgical insult to the patient and lead to better perioperative outcomes, with quicker return to function.

Efficacy and safety of robotic versus laparoscopic liver resection for hepatocellular carcinoma: a propensity score-matched retrospective cohort study

BACKGROUND

Evidence concerning long-term outcome of robotic liver resection (RLR) and laparoscopic liver resection (LLR) for hepatocellular carcinoma (HCC) patients is scarce.

METHODS

This study enrolled all patients who underwent RLR and LLR for resectable HCC between July 2016 and July 2021. Propensity score matching (PSM) was employed to create a 1:3 match between the RLR and LLR groups. A comprehensive collection and analysis of patient data regarding efficacy and safety have been conducted, along with the evaluation of the learning curve for RLR.

RESULTS

Following PSM, a total of 341 patients were included, with 97 in the RLR group and 244 in the LLR group. RLR group demonstrated a significantly longer operative time (median [IQR], 210 [152.0-298.0] min vs. 183.5 [132.3-263.5] min; p = 0.04), with no significant differences in other perioperative and short-term postoperative outcomes. Overall survival (OS) was similar between the two groups (p = 0.43), but RLR group exhibited improved recurrence-free survival (RFS) (median of 65 months vs. 56 months, p = 0.006). The estimated 5-year OS for RLR and LLR were 74.8% (95% CI: 65.4-85.6%) and 80.7% (95% CI: 74.0-88.1%), respectively. The estimated 5-year RFS for RLR and LLR were 58.6% (95% CI: 48.6-70.6%) and 38.3% (95% CI: 26.4-55.9%), respectively. In the multivariate Cox regression analysis, RLR (HR: 0.586, 95% CI (0.393-0.874), p = 0.008) emerged as an independent predictor of reducing recurrence rates and enhanced RFS. The operative learning curve indicates that approximately after the 11th case, the learning curve of RLR stabilized and entered a proficient phase.

CONCLUSIONS

OS was comparable between RLR and LLR, and while RFS was improved in the RLR group. RLR demonstrates oncological effectiveness and safety for resectable HCC.

Efficacy and perioperative safety of different future liver remnant modulation techniques: a systematic review and network meta-analysis

BACKGROUND

In daily clinical practice, different future liver remnant (FLR) modulation techniques are increasingly used to allow a liver resection in patients with insufficient FLR volume. This systematic review and network meta-analysis aims to compare the efficacy and perioperative safety of portal vein ligation (PVL), portal vein embolization (PVE), liver venous deprivation (LVD) and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS).

METHODS

A literature search for studies comparing liver resections following different FLR modulation techniques was performed in MEDLINE, Embase and Cochrane Central, and pairwise and network meta-analyses were conducted.

RESULTS

Overall, 23 studies comprising 1557 patients were included. LVD achieved the greatest increase in FLR (17.32 %, 95% CI 2.49-32.15), while ALPPS was most effective in preventing dropout before the completion hepatectomy (OR 0.29, 95% CI 0.15-0.55). PVL tended to be associated with a longer time to completion hepatectomy (MD 5.78 days, 95% CI -0.67-12.23). Liver failure occurred less frequently after LVD, compared to PVE (OR 0.35, 95% CI 0.14-0.87) and ALPPS (OR 0.28, 95% CI 0.09-0.85).

DISCUSSION

ALPPS and LVD seem superior to PVE and PVL in terms of achieved FLR increase and subsequent treatment completion. LVD was associated with lower rates of post hepatectomy liver failure, compared to both PVE and ALPPS. A summary of the protocol has been prospectively registered in the PROSPERO database (CRD42022321474).

Intraoperative artificial intelligence system identifying liver vessels in laparoscopic liver resection: a retrospective experimental study

BACKGROUND

The precise recognition of liver vessels during liver parenchymal dissection is the crucial technique for laparoscopic liver resection (LLR). This retrospective feasibility study aimed to develop artificial intelligence (AI) models to recognize liver vessels in LLR, and to evaluate their accuracy and real-time performance.

METHODS

Images from LLR videos were extracted, and the hepatic veins and Glissonean pedicles were labeled separately. Two AI models were developed to recognize liver vessels: the "2-class model" which recognized both hepatic veins and Glissonean pedicles as equivalent vessels and distinguished them from the background class, and the "3-class model" which recognized them all separately. The Feature Pyramid Network was used as a neural network architecture for both models in their semantic segmentation tasks. The models were evaluated using fivefold cross-validation tests, and the Dice coefficient (DC) was used as an evaluation metric. Ten gastroenterological surgeons also evaluated the models qualitatively through rubric.

RESULTS

In total, 2421 frames from 48 video clips were extracted. The mean DC value of the 2-class model was 0.789, with a processing speed of 0.094 s. The mean DC values for the hepatic vein and the Glissonean pedicle in the 3-class model were 0.631 and 0.482, respectively. The average processing time for the 3-class model was 0.097 s. Qualitative evaluation by surgeons revealed that false-negative and false-positive ratings in the 2-class model averaged 4.40 and 3.46, respectively, on a five-point scale, while the false-negative, false-positive, and vessel differentiation ratings in the 3-class model averaged 4.36, 3.44, and 3.28, respectively, on a five-point scale.

CONCLUSION

We successfully developed deep-learning models that recognize liver vessels in LLR with high accuracy and sufficient processing speed. These findings suggest the potential of a new real-time automated navigation system for LLR.

An update on liver surgery - a new terminology and modern techniques

Liver surgery is the cornerstone of the curative treatment of malignant liver tumors. However, the liver anatomy is very complex, and liver surgery is still associated with relevant morbidity despite many technical advances. The Brisbane nomenclature is used worldwide to classify liver resection. However, this nomenclature has several limitations as multiple terms are used for the same type of resection. Non-anatomical resections, multiple resections, and combined bilio-vascular resections were not mentioned. Therefore, new terminologies have been proposed for the precise and simple classification of liver resection. Furthermore, in recent years, many technical innovations have been introduced in liver surgery, such as 3D imaging systems and indocyanine green fluorescence, for better preoperative and intraoperative identification of tumor localization and critical vascular structures. Minimally invasive techniques are used more frequently in liver surgery. Potential benefits include less intraoperative blood loss, less pain, and a shorter hospital stay. The implementation of robotic systems also has an impact on liver surgery, and the number of cases reported in the literature is constantly increasing. The potential benefits of robotic liver resection over laparoscopic liver resection will be the subject of future studies.

Non-Stick Liver Parenchymal Transection With Saline-Linked Bipolar Clamp-Crush Technique in Robotic Liver Resection

Background Without satisfactory instruments, liver parenchymal transection during robotic liver resection (RLR) remains challenging. We combined the commonly used bipolar clamp-crush technique with the saline drip, achieving a comfortable liver resection without coagulated liver tissues sticking to the bipolar forceps. Methods Between December 2022 and March 2023, six RLRs were performed using the saline-linked bipolar clamp-crush method for both anatomical and non-anatomical liver resections. We assessed the safety and feasibility of our robotic liver parenchymal transection technique. Results Three of six patients were diagnosed with colorectal liver metastasis, two with hepatocellular carcinoma (HCC), and the other with intrahepatic bile duct stricture. Three of the six patients received anatomical liver resection, and the other three underwent non-anatomical liver resection. There were no conversions to open surgery. The median operative time and estimated blood loss were 406.5 minutes (196-670 minutes) and 5 ml (5-465 ml), respectively. The median length of the postoperative hospital stay was nine days (7-10 days). Postoperative complications (Clavien-Dindo classification grade II or more) or mortality were not encountered in this cohort. Conclusion We presented here our saline-linked bipolar clamp-crush method for liver parenchymal transection in RLR. By simply adding the saline drip to the commonly used bipolar clamp-crush technique, non-stick and comfortable liver parenchymal transection is now possible. This technique may help overcome the limitations of currently available robotic instruments for liver parenchymal resection.

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