Laparoscopic Liver Resection of Segments 7 and 8: from the Initial Restrictions to the Current Indications

Explainable artificial intelligence prediction-based model in laparoscopic liver surgery for segments 7 and 8: an international multicenter study

BACKGROUND

Artificial intelligence (AI) is becoming more useful as a decision-making and outcomes predictor tool. We have developed AI models to predict surgical complexity and the postoperative course in laparoscopic liver surgery for segments 7 and 8.

METHODS

We included patients with lesions located in segments 7 and 8 operated by minimally invasive liver surgery from an international multi-institutional database. We have employed AI models to predict surgical complexity and postoperative outcomes. Furthermore, we have applied SHapley Additive exPlanations (SHAP) to make the AI models interpretable. Finally, we analyzed the surgeries not converted to open versus those converted to open.

RESULTS

Overall, 585 patients and 22 variables were included. Multi-layer Perceptron (MLP) showed the highest performance for predicting surgery complexity and Random Forest (RF) for predicting postoperative outcomes. SHAP detected that MLP and RF gave the highest relevance to the variables "resection type" and "largest tumor size" for predicting surgery complexity and postoperative outcomes. In addition, we explored between surgeries converted to open and non-converted, finding statistically significant differences in the variables "tumor location," "blood loss," "complications," and "operation time."

CONCLUSION

We have observed how the application of SHAP allows us to understand the predictions of AI models in surgical complexity and the postoperative outcomes of laparoscopic liver surgery in segments 7 and 8.

Impact of Minimally Invasive Surgery on Anatomic Liver Segmentectomy Using the Extrahepatic Glissonean Approach

Accurate minimally invasive anatomic liver (sub)segmentectomy (MIAS) is technically demanding and not yet standardized, and its surgical outcomes are undefined. To study the impact of the minimally invasive approach on perioperative outcomes of anatomic liver (sub)segmentectomy (AS), we retrospectively studied and compared perioperative outcomes of 99 open AS (OAS) and 112 MIAS (laparoscopic 77, robotic 35) cases using the extrahepatic Glissonean approach, based on the 1:1 propensity score matched analyses. After matching (71:71), MIAS was superior to OAS in terms of blood loss (p < 0.0001), maximum postoperative serum total bilirubin (p < 0.0001), C-reactive protein (p = 0.034) levels, R0 resection rate (p = 0.021), bile leak (p = 0.049), and length of hospital stay (p < 0.0001). The matched robotic and laparoscopic AS groups (30:30) had comparable outcomes in terms of operative time, blood loss, transfusion, open conversion, postoperative morbidity and mortality, R0 resection, and hospital stay, although the rate of Pringle maneuver application (p = 0.0002) and the postoperative aspartate aminotransferase level (p = 0.002) were higher in the robotic group. Comparing the matched posterosuperior (sub)segmentectomy cases or unmatched repeat hepatectomy cases between MIAS and OAS, we observed significantly less blood loss and shorter hospital stays in MIAS. Robotic AS yielded comparable outcomes with laparoscopic AS in the posterosuperior (sub)segmentectomy and repeat hepatectomy settings, despite the worse tumor and procedural backgrounds in robotic AS. In conclusion, various types of MIAS standardized by the extrahepatic Glissonean approach were feasible and safe with more favorable perioperative outcomes than those of OAS. Although robotic AS had almost comparable outcomes with laparoscopic AS, robotics may serve to decrease the surgical difficulty of MIAS in selected patients undergoing posterosuperior (sub)segmentectomy and repeat hepatectomy.

Laparoscopic anatomical versus non-anatomical liver resection for hepatocellular carcinoma in the posterosuperior segments: a propensity score matched analysis

Background

Since laparoscopic anatomical resection (LAR) for tumors, especially located in the posterosuperior (PS) segments of the liver remains difficult, laparoscopic non-anatomical resection (LNAR) are generally preferred. To compare the clinical outcomes between LAR and LNAR for hepatocellular carcinoma (HCC) located in the PS segments.

Methods

We retrospectively reviewed the data for 1,029 patients who underwent hepatectomy for HCC between 2004 and 2019. Of 167 patients who underwent laparoscopic hepatectomy for HCC in PS segments, 64 underwent LNAR and 103 underwent LAR. Patients were matched one-to-one using propensity score matching (46:46).

Results

LNAR was associated with significantly shorter operation time (P=0.001), lower estimated blood loss (P=0.001), lower transfusion rate (P=0.006) and shorter hospital stay (P=0.012) than LAR. The respective 1- ,3-, and 5-year overall survival rates (LAR: 95.3%, 87.1%, and 77.8%; LNAR: 96.7%, 91.6%, and 85.0%; P=0.262) and recurrence-free survival rates (LAR: 75.7%, 70.3%, and 68.9%; LNAR: 81.8%, 58.3%, and 55.3%; P=0.879) were similar. The intrahepatic recurrence rate was significantly higher in LNAR group than in LAR group (78.6% vs. 57.1%, P=0.023), but the post-recurrence treatments differed significantly between the two groups (P=0.016); the re-resection rate was much greater in the LNAR group (45.0% vs. 0%) group. The respective 1-, 3-, and 5-year post-recurrence survival rates were similar in the LAR and LNAR groups (P=0.212). After recurrence, survival in re-resection group was significantly greater than not (P=0.026).

Conclusions

LNAR is safe and feasible for HCC located in PS segments, and provided acceptable oncologic outcomes that are comparable to those of LAR. LNAR can be considered for patient with tumor located in PS segment when LAR is not feasible.

Process model analysis of parenchyma sparing laparoscopic liver surgery to recognize surgical steps and predict impact of new technologies

BACKGROUND

Surgical process model (SPM) analysis is a great means to predict the surgical steps in a procedure as well as to predict the potential impact of new technologies. Especially in complicated and high-volume treatments, such as parenchyma sparing laparoscopic liver resection (LLR), profound process knowledge is essential for enabling improving surgical quality and efficiency.

METHODS

Videos of thirteen parenchyma sparing LLR were analyzed to extract the duration and sequence of surgical steps according to the process model. The videos were categorized into three groups, based on the tumor locations. Next, a detailed discrete events simulation model (DESM) of LLR was built, based on the process model and the process data obtained from the endoscopic videos. Furthermore, the impact of using a navigation platform on the total duration of the LLR was studied with the simulation model by assessing three different scenarios: (i) no navigation platform, (ii) conservative positive effect, and (iii) optimistic positive effect.

RESULTS

The possible variations of sequences of surgical steps in performing parenchyma sparing depending on the tumor locations were established. The statistically most probable chain of surgical steps was predicted, which could be used to improve parenchyma sparing surgeries. In all three categories (i-iii) the treatment phase covered the major part (~ 40%) of the total procedure duration (bottleneck). The simulation results predict that a navigation platform could decrease the total surgery duration by up to 30%.

CONCLUSION

This study showed a DESM based on the analysis of steps during surgical procedures can be used to predict the impact of new technology. SPMs can be used to detect, e.g., the most probable workflow paths which enables predicting next surgical steps, improving surgical training systems, and analyzing surgical performance. Moreover, it provides insight into the points for improvement and bottlenecks in the surgical process.

Safety and Feasibility of Laparoscopic Parenchymal-Sparing Hepatectomy for Lesions with Proximity to Major Vessels in Posterosuperior Liver Segments 7 and 8

Laparoscopic parenchymal-sparing hepatectomy (PSH) for lesions with proximity to major vessels (PMV) in posterosuperior segments (PSS) has not yet been sufficiently examined. The aim of this study is to examine the safety and feasibility of laparoscopic PSH for lesions with PMV in PSS 7 and 8. We retrospectively reviewed the outcomes of laparoscopic liver resection (LLR) and open liver resection (OLR) for PSS lesions and focused on patients who underwent laparoscopic PSH for lesions with PMV in PSS. Blood loss was lower in the LLR group (n = 110) than the OLR group (n = 16) (p = 0.009), and no other short-term outcomes were significantly different. Compared to the pure LLR group (n = 93), there were no positive surgical margins or complications in hand-assisted laparoscopic surgery (HALS) (n = 17), despite more tumors with PMV (p = 0.009). Regarding pure LLR for one tumor lesion, any short-term outcomes in addition to the operative time were not significantly different between the PMV (n = 23) and no-PMV (n = 48) groups. The present findings indicate that laparoscopic PSH for lesions with PMV in PSS is safe and feasible in a matured team, and the HALS technique still plays an important role.

Comparison between the difficulty of laparoscopic limited liver resections of tumors located in segment 7 versus segment 8: An international multicenter propensity-score matched study

BACKGROUND

Presently, according to different difficulty scoring systems, there is no difference in complexity estimation of laparoscopic liver resection (LLR) of segments 7 and 8. However, there is no published data supporting this assumption. To date, no studies have compared the outcomes of laparoscopic parenchyma-sparing resection of the liver segments 7 and 8.

METHODS

A post hoc analysis of patients undergoing LLR of segments 7 and 8 in 46 centers between 2004 and 2020 was performed. 1:1 Propensity score matching (PSM) was used to compare isolated LLR of segments 7 and 8. Subset analyses were also performed to compare atypical resections and segmentectomies of 7 and 8.

RESULTS

A total of 2411 patients were identified, and 1691 patients met the inclusion criteria. Comparison after PSM between the entire cohort of segment 7 and segment 8 resections revealed inferior results for segment 7 resection in terms of increased blood loss, blood transfusions, and conversions to open surgery. Subset analyses of only atypical resections similarly demonstrated poorer outcomes for segment 7 in terms of increased blood loss, operation time, blood transfusions, and conversions to open surgery. Conversely, a subgroup analysis of segmentectomies after PSM found better outcomes for segment 7 in terms of a shorter operation time and hospital stay.

CONCLUSION

Differences in the outcomes of segments 7 and 8 resections suggest a greater difficulty of laparoscopic atypical resection of segment 7 compared to segment 8, and greater difficulty of segmentectomy 8 compared to segmentectomy 7.

Pure laparoscopic vs. hand-assisted liver surgery for segments 7 and 8: propensity score matching analysis

BACKGROUND

Laparoscopic liver resection of tumors located in segments 7 and 8 are considered a complex resection. The aim of this study was to compare the intraoperative and early postoperative outcomes of patients operated by pure laparoscopic (PLS) vs hand-assisted laparoscopic surgery (HALS).

METHODS

From January 2003 to January 2021, we included patients with minimally invasive surgery for lesions located in segments 7 and 8. To overcome selection bias, we performed 1:1 propensity score matching (PSM) between HALS and PLS cohorts, including 30 patients in each of the groups. Of the 60 patients who underwent PSM, we compared the first 30 patients with the following 30 patients.

RESULTS

A total of 79 LLRs were performed, 46 by HALS and 33 by PLS. After PSM, in the PLS cohort, cirrhosis was more frequent (33.3% vs. 13.3%, p = 0.02). The surgical time, blood loss, Pringle maneuver, clamping time, and morbidity were similar between both groups, but with a lower hospital stay in the PLS group (3 days vs. 4 days, p < 0.01). In the first 30 patients who underwent LLR, the use of PLS was lower than the use of HALS, increasing due to the learning curve (16.7% in the first period vs. 83.3% in the second period; p < 0.01). The hospital stay was lower in the second period due to the more frequent use of PLS (3 vs. 4 days, p < 0.01).

CONCLUSION

PLS presents similar intraoperative and early postoperative results with lower hospital stay for lesions located in segments 7 and 8 compared to HALS. In centers with experience in LLRs, PLS could be performed safely in these segments.