Critical appraisal of the learning curve of minimally invasive hepatectomy: experience with the first 200 cases of a Southeast Asian early adopter

Comparative cost-effectiveness of open, laparoscopic, and robotic liver resection: A systematic review and network meta-analysis

BACKGROUND

This study evaluated the cost-effectiveness of open, laparoscopic, and robotic liver resection.

METHODS

A comprehensive literature review and Bayesian network meta-analysis were conducted. Surface under cumulative ranking area values, mean difference, odds ratio, and 95% credible intervals were calculated for all outcomes. Cluster analysis was performed to determine the most cost-effective clustering approach. Costs-morbidity, costs-mortality, and costs-efficacy were the primary outcomes assessed, with postoperative overall morbidity, mortality, and length of stay associated with total costs for open, laparoscopic, and robotic liver resection.

RESULTS

Laparoscopic liver resection incurred the lowest total costs (laparoscopic liver resection versus open liver resection: mean difference -2,529.84, 95% credible intervals -4,192.69 to -884.83; laparoscopic liver resection versus robotic liver resection: mean difference -3,363.37, 95% credible intervals -5,629.24 to -1,119.38). Open liver resection had the lowest procedural costs but incurred the highest hospitalization costs compared to laparoscopic liver resection and robotic liver resection. Conversely, robotic liver resection had the highest total and procedural costs but the lowest hospitalization costs. Robotic liver resection and laparoscopic liver resection had a significantly reduced length of stay than open liver resection and showed less postoperative morbidity. Laparoscopic liver resection resulted in the lowest readmission and liver-specific complication rates. Laparoscopic liver resection and robotic liver resection demonstrated advantages in costs-morbidity efficiency. While robotic liver resection offered notable benefits in mortality and length of stay, these were balanced against its highest total costs, presenting a nuanced trade-off in the costs-mortality and costs-efficacy analyses.

CONCLUSION

Laparoscopic liver resection represents a more cost-effective option for hepatectomy with superior postoperative outcomes and shorter length of stay than open liver resection. Robotic liver resection, though costlier than laparoscopic liver resection, along with laparoscopic liver resection, consistently exceeds open liver resection in surgical performance.

Towards a Standardization of Learning Curve Assessment in Minimally Invasive Liver Surgery

OBJECTIVE

The aim was to analyze the learning curves of minimal invasive liver surgery(MILS) and propose a standardized reporting.

SUMMARY BACKGROUND DATA

MILS offers benefits compared to open resections. For a safe introduction along the learning curve, formal training is recommended. However, definitions of learning curves and methods to assess it lack standardization.

METHODS

A systematic review of PubMed, Web of Science, and CENTRAL databases identified studies on learning curves in MILS. The primary outcome was the number needed to overcome the learning curve. Secondary outcomes included endpoints defining learning curves, and characterization of different learning phases(competency, proficiency and mastery).

RESULTS

60 articles with 12'241 patients and 102 learning curve analyses were included. The laparoscopic and robotic approach was evaluated in 71 and 18 analyses and both approaches combined in 13 analyses. Sixty-one analyses (60%) based the learning curve on statistical calculations. The most often used parameters to define learning curves were operative time (n=64), blood loss (n=54), conversion (n=42) and postoperative complications (n=38). Overall competency, proficiency and mastery were reached after 34 (IQR 19-56), 50 (IQR 24-74), 58 (IQR 24-100) procedures respectively. Intraoperative parameters improved earlier (operative time: competency to proficiency to mastery: -13%, 2%; blood loss: competency to proficiency to mastery: -33%, 0%; conversion rate (competency to proficiency to mastery; -21%, -29%), whereas postoperative complications improved later (competency to proficiency to mastery: -25%, -41%).

CONCLUSIONS

This review summarizes the highest evidence on learning curves in MILS taking into account different definitions and confounding factors. A standardized three-phase reporting of learning phases (competency, proficiency, mastery) is proposed and should be followed.

Examining the application of the IDEAL framework in the reporting and evaluation of innovative invasive procedures: secondary qualitative analysis of a systematic review

OBJECTIVES

The development of new surgical procedures is fundamental to advancing patient care. The Idea, Developments, Exploration, Assessment and Long-term (IDEAL) framework describes study designs for stages of innovation. It can be difficult to apply due to challenges in defining and identifying innovative procedures. This study examined how the IDEAL framework is operationalised in real-world settings; specifically, the types of innovations evaluated using the framework and how authors justify their choice of IDEAL study design.

DESIGN

Secondary qualitative analysis of a systematic review.

DATA SOURCES

Citation searches (Web of Science and Scopus) identified studies following the IDEAL framework and citing any of the ten key IDEAL/IDEAL_D papers.

ELIGIBILITY CRITERIA

Studies of invasive procedures/devices of any design citing any of the ten key IDEAL/IDEAL_D papers.

DATA EXTRACTION AND SYNTHESIS

All relevant text was extracted. Three frameworks were developed, namely: (1) type of innovation under evaluation; (2) terminology used to describe stage of innovation and (3) reported rationale for IDEAL stage.

RESULTS

48 articles were included. 19/48 described entirely new procedures, including those used for the first time in a different clinical context (n=15/48), reported as IDEAL stage 2a (n=8, 53%). Terminology describing stage of innovation was varied, inconsistent and ambiguous and was not defined. Authors justified their choice of IDEAL study design based on limitations in published evidence (n=36) and unknown feasibility and safety (n=32) outcomes.

CONCLUSION

Identifying stage of innovation is crucial to inform appropriate study design and governance decisions. Authors' rationale for choice of IDEAL stage related to the existing evidence base or lack of sufficient outcome data for procedures. Stage of innovation was poorly defined with inconsistent descriptions. Further work is needed to develop methods to identify innovation to inform practical application of the IDEAL framework. Defining the concept of innovation in terms of uncertainty, risk and degree of evidence may help to inform decision-making.

10 years, 100 robotic major hepatectomies: a single-center experience

INTRODUCTION

Adoption of robotic liver resections has been gradually increasing throughout the HPB surgical community over the past decade. Currently there is limited literature which demonstrates a significant benefit of robotic surgery for major hepatectomies over open or laparoscopic. As one of the first centers to develop a robotic HPB program, we have experienced improved outcomes over time with increasing utilization of robotics. Herein, we present our 10-year experience and outcomes for major robotic liver resections.

METHODS

From 2012 to 2022, 361 robotic liver procedures were performed, including 100 major hepatectomies. A retrospective data review of the electronic medical record was performed evaluating outcomes after robotic major hepatectomy. Outcomes for the first 50 cases (Group A) and second 50 cases (Group B) were compared to identify any improvements in practice. Demographic and clinical outcome variables were analyzed. Data were assessed for normality, and Wilcoxon rank-sum, χ2 tests, and a logistic regression model were performed appropriate for the data. Stata v.17 was utilized, and significance was set as p < .05.

RESULTS

There was no difference in median operative time (258 vs 256 min), EBL (500 vs 500 mL), median LOS (5 vs 3.5 days), 90-day readmission (14% vs 24%), major complications (14% vs 20%), and 90-day mortality (6% vs 4%) between early and late cases, respectively. ICU admissions and conversion rates were significantly lower in group B (14.0% vs 48.0%), while expert level difficulty indices were higher (82% vs 58%).

CONCLUSION

Development of a robotic liver program with good outcomes is feasible over time. Our data suggest that our institutional learning curve for robotic major hepatectomy plateaued at approximately 50 cases.

Propensity score-matched analysis of laparoscopic-assisted and hand-assisted laparoscopic liver resection versus pure laparoscopic liver resection: an international multicenter study

BACKGROUND

Laparoscopic-assisted (LALR) and hand-assisted (HALR) liver resections have been utilized during the early adoption phase by surgeons when transitioning from open surgery to pure LLR. To date, there are limited data reporting on the outcomes of LALR or HALR compared to LLR. The objective was to compare the perioperative outcomes after LALR and HALR versus pure LLR.

METHODS

This is an international multicentric analysis of 6609 patients undergoing minimal-invasive liver resection at 21 centers between 2004 and 2019. Perioperative outcomes were analyzed after propensity score matching (PSM) comparison between LALR and HALR versus LLR.

RESULTS

5279 cases met study criteria of whom 5033 underwent LLR (95.3%), 146 underwent LALR (2.8%) and 100 underwent HALR (1.9%). After 1:4 PSM, LALR was associated with inferior outcomes as evidenced by the longer postoperative stay, higher readmission rate, higher major morbidity rate and higher in-hospital mortality rate. Similarly, 1:6 PSM comparison between HALR and LLR also demonstrated poorer outcomes associated with HALR as demonstrated by the higher open conversion rate and higher blood transfusion rate. All 3 approaches technical variants demonstrated the same oncological radicality (R1 rate).

CONCLUSION

LALR and HALR performed during the learning curve was associated with inferior perioperative outcomes compared to pure LLR.

Defining Global Benchmarks for Laparoscopic Liver Resections: An International Multicenter Study

OBJECTIVE

To establish global benchmark outcomes indicators after laparoscopic liver resections (L-LR).

BACKGROUND

There is limited published data to date on the best achievable outcomes after L-LR.

METHODS

This is a post hoc analysis of a multicenter database of 11,983 patients undergoing L-LR in 45 international centers in 4 continents between 2015 and 2020. Three specific procedures: left lateral sectionectomy (LLS), left hepatectomy (LH), and right hepatectomy (RH) were selected to represent the 3 difficulty levels of L-LR. Fifteen outcome indicators were selected to establish benchmark cutoffs.

RESULTS

There were 3519 L-LR (LLS, LH, RH) of which 1258 L-LR (40.6%) cases performed in 34 benchmark expert centers qualified as low-risk benchmark cases. These included 659 LLS (52.4%), 306 LH (24.3%), and 293 RH (23.3%). The benchmark outcomes established for operation time, open conversion rate, blood loss ≥500 mL, blood transfusion rate, postoperative morbidity, major morbidity, and 90-day mortality after LLS, LH, and RH were 209.5, 302, and 426 minutes; 2.1%, 13.4%, and 13.0%; 3.2%, 20%, and 47.1%; 0%, 7.1%, and 10.5%; 11.1%, 20%, and 50%; 0%, 7.1%, and 20%; and 0%, 0%, and 0%, respectively.

CONCLUSIONS

This study established the first global benchmark outcomes for L-LR in a large-scale international patient cohort. It provides an up-to-date reference regarding the "best achievable" results for L-LR for which centers adopting L-LR can use as a comparison to enable an objective assessment of performance gaps and learning curves.

Systematic review and meta-analysis of difficulty scoring systems for laparoscopic and robotic liver resections

INTRODUCTION

The ability to stratify the difficulty of minimally invasive liver resection (MILR) allows surgeons at different phases of the learning curve to tackle cases of appropriate difficulty safely. Several difficulty scoring systems (DSS) have been formulated which attempt to accurately stratify this difficulty. The present study aims to review the literature pertaining to the existing DSS for MILR.

METHODS

We performed a systematic review and metanalysis of the literature reporting on the formulation, supporting data, and comparison of DSS for MILR.

RESULTS

A total of 11 studies were identified which reported on the formulation of unique DSS for MILR. Five of these (Ban, Iwate, Hasegawa, Institut Mutaliste Montsouris [IMM], and Southampton DSS) were externally validated and shown to predict difficulty of MILR via a range of outcome measures. The Ban DSS was supported by pooled data from 10 studies (9 LLR, 1 RLR), Iwate by 10 studies (8 LLR, 2 RLR), Hasegawa by four studies (all LLR), IMM by eight studies (all LLR), and Southampton by five studies (all LLR). There was no clear superior DSS.

CONCLUSION

The existing DSS were all effective in predicting difficulty of MILR. Present studies comparing between DSS have not established a clear superior system, and the five main DSS have been found to be predictive of difficulty in LLR and two of these in RLR.

Robotic Revision of Hepaticojejunostomy for Benign Biliary Stricture

Surgical revision of biliary enteric anastomoses (BEA) can be a challenging undertaking and a robotic platform may provide advantages that address many of the technical obstacles. We present our technical approach and outcomes for patients undergoing robotic revision of BEA for benign strictures. A retrospective review was performed for robot-assisted benign BEA revision at our institution. Operative details, perioperative metrics, and outcomes are reported. Four patients underwent anastomotic revision following previously failed non-operative management. There were no intraoperative complications, mean length of stay was 4-days, and all patients experienced resolution of presenting clinical signs and symptoms. No patients required reoperation and there was no mortality. Postoperative outcomes were consistent with findings reported for other interventional modalities. Based on our experience we conclude robotic intervention in this context is safe and improves the technical feasibility of this complex procedure.

Minimally Invasive vs Open Major Hepatectomies for Liver Malignancies: a Propensity Score-Matched Analysis

BACKGROUND

The majority of evidence with regards to minimally invasive liver resection (MILR) favors its application in minor hepatectomies. We conducted a propensity score-matched (PSM) analysis to determine its feasibility and safety in major hepatectomies (MIMH) for liver malignancies.

METHODS

Retrospective review of 130 patients who underwent MIMH and 490 patients who underwent open major hepatectomy (OMH) for malignant pathologies was performed. PSM in a 1:1 ratio identified two groups of patients with similar baseline clinicopathological characteristics. Perioperative outcomes were then compared. Major hepatectomies included traditional major (>3 segments) and technical major hepatectomies (right anterior and right posterior sectionectomies).

RESULTS

Both cohorts were well-matched for baseline characteristics after PSM. Of 130 MIMH cases, there were 12 conversions to open. Comparison of perioperative outcomes demonstrated a significant association of MIMH with longer operation time and more frequent application of Pringle's maneuver (PM), but decreased postoperative stay. These results were consistent on a subgroup analysis that only included patients undergoing traditional major hepatectomies. A second subgroup analysis restricted to cirrhotic patients demonstrated that while perioperative outcomes were equivalent, MIMH was similarly associated with a longer operative time. Subset analyses of resections performed after 2015 demonstrated that MIMH was additionally associated with a lower postoperative morbidity compared to OMH.

CONCLUSION

Comparison of perioperative and short-term oncological outcomes between MIMH and OMH for malignancies demonstrated that MIMH is feasible and safe. It is associated with a shorter hospital stay at the expense of a longer operation time compared to OMH.

Impact of introduction of an enhanced recovery protocol on the outcomes of laparoscopic liver resections: A propensity-score matched study

BACKGROUND

Presently, data on the impact of enhanced recovery protocols on the outcomes of laparoscopic liver resection remain limited. We performed propensity matched analysis comparing the outcomes between patients undergoing laparoscopic liver resection before and after the introduction of an enhanced recovery protocol.

METHODS

Between 2013 and 2019, 462 consecutive patients underwent laparoscopic liver resection by 3 surgeons of which 360 met the study inclusion criteria. There were 89 patients who underwent surgery under an enhanced recovery protocol and 271 without an enhanced recovery protocol. One-to-one propensity matched analysis was performed for 84 enhanced recovery protocol patients and 84 nonenhanced recovery protocol patients.

RESULTS

Comparisons between propensity matched cohorts revealed that patients who received laparoscopic liver resection with enhanced recovery protocol had reduced median blood loss (200 vs 300 mL, P = .013), postoperative stay (3 vs 4 days, P = .003), and lower open conversion rates (0% vs 8.3%, P = .008). There was no difference in other key perioperative outcomes such as operation time, postoperative morbidity, postoperative major morbidity, and 30-day readmission rates.

CONCLUSION

A combined approach of enhanced recovery protocol and laparoscopic liver resection was associated with improved perioperative outcomes as opposed to laparoscopic liver resection alone.

Impact of tumor size on the difficulty of minimally invasive liver resection

INTRODUCTION

We performed this study in order to investigate the impact of tumour size on the difficulty of MILR, as well as to elucidate the optimal tumour size cut-off/s to distinguish between 'easy' and 'difficult' MILRs.

MATERIALS AND METHODS

This is retrospective review of 603 consecutive patients who underwent MILR between 2006 and 2019 of which 461 met the study inclusion criteria. We first conducted an exploratory analysis to visualize the associations between tumor size and various surrogates of laparoscopic difficulty in order to determine to optimal tumor size cutoff for stratification. Visual inspection of flexible spline-based models as well as quantitative evidence determined that perioperative outcomes differed between patients with tumor size of 30-69 mm and tumours ≥70 mm. These cutoffs were used for further downstream analyses.

RESULTS

The cohort of 461 patients was divided into 3 groups based on tumour diameter size. Patients with larger tumours experienced longer operating times ((PGroup 2 vs 1<0.001, PGroup 3 vs 1<0.001, PGroup 3 vs 2<0.001), higher blood loss (PGroup 2 vs 1<0.001, PGroup 3 vs 1<0.001, PGroup 3 vs 2<0.001), as well as significantly longer hospital stay (PGroup 2 vs 1<0.001, PGroup 3 vs 1<0.001, PGroup 3 vs 2<0.001). There was a monotonic trend towards increasing blood transfusion rates (P = 0.006), overall morbidity (P = 0.029) and 90-day mortality rates (P = 0.047) with increasing tumour size.

CONCLUSION

Although tumour size of 30 mm serves as an optimal cut-off for predicting difficult resections as per the Iwate criteria, a trichotomy (<30 mm, 30-69 mm, ≥70 mm) may provide additional granularity. Further large-scale prospective studies are needed to corroborate these findings.

Evolution and trends in the adoption of laparoscopic liver resection in Singapore: Analysis of 300 cases

ABSTRACT Introduction: The introduction of laparoscopic surgery has changed abdominal surgery. We evaluated the evolution and changing trends associated with adoption of laparoscopic liver resection (LLR) and the experience of a surgeon without prior LLR experience. Methods: A retrospective review of 310 patients who underwent LLR performed by a single surgeon from 2011 to 2020 was conducted. Exclusion criteria were patients who underwent laparoscopic liver surgeries such as excision biopsy, local ablation, drainage of abscesses and deroofing of liver cysts. There were 300 cases and the cohort was divided into 5 groups of 60 patients. Results: There were 288 patients who underwent a totally minimally invasive approach, including 28 robotic-assisted procedures. Open conversion occurred for 13 (4.3%) patients; the conversion rate decreased significantly from 10% in the initial period to 3.3% subsequently. There were 83 (27.7%) major resections and 131 (43.7%) resections were performed for tumours in the difficult posterosuperior location. There were 152 (50.7%) patients with previous abdominal surgery, including 52 (17.3%) repeat liver resections for recurrent tumours, and 60 patients had other concomitant operations. According to the Iwate criteria, 135 (44.7%) were graded as high/expert difficulty. Major morbidity (>grade 3a) occurred in 12 (4.0%) patients and there was no 30-day mortality. Comparison across the 5 patient groups demonstrated a significant trend towards older patients, higher American Society of Anesthesiologists (ASA) score, increasing frequency of LLR with previous abdominal surgery, increasing frequency of portal hypertension and huge tumours, decreasing blood loss and decreasing transfusion rate across the study period. Surgeon experience (≤60 cases) and Institut Mutualiste Montsouris (IMM) high grade resections were independent predictors of open conversion. Open conversion was associated with worse perioperative outcomes such as increased blood loss, transfusion rate, morbidity and length of stay. Conclusion: LLR can be safely adopted for resections of all difficulty grades, including major resections and for tumours located in the difficult posterosuperior segments, with a low open conversion rate. Keywords: Laparoscopic hepatectomy, laparoscopic liver resection, robotic hepatectomy, robotic liver resection, Singapore

Statistical Process Control Charts for Monitoring Next-Generation Sequencing and Bioinformatics Turnaround in Precision Medicine Initiatives

Purpose

Precision oncology, such as next generation sequencing (NGS) molecular analysis and bioinformatics are used to guide targeted therapies. The laboratory turnaround time (TAT) is a key performance indicator of laboratory performance. This study aims to formally apply statistical process control (SPC) methods such as CUSUM and EWMA to a precision medicine programme to analyze the learning curves of NGS and bioinformatics processes.

Patients and Methods

Trends in NGS and bioinformatics TAT were analyzed using simple regression models with TAT as the dependent variable and chronologically-ordered case number as the independent variable. The M-estimator "robust" regression and negative binomial regression were chosen to serve as sensitivity analyses to each other. Next, two popular statistical process control (SPC) approaches which are CUSUM and EWMA were utilized and the CUSUM log-likelihood ratio (LLR) charts were also generated. All statistical analyses were done in Stata version 16.0 (StataCorp), and nominal P < 0.05 was considered to be statistically significant.

Results

A total of 365 patients underwent successful molecular profiling. Both the robust linear model and negative binomial model showed statistically significant reductions in TAT with accumulating experience. The EWMA and CUSUM charts of overall TAT largely corresponded except that the EWMA chart consistently decreased while the CUSUM analyses indicated improvement only after a nadir at the 82^nd case. CUSUM analysis found that the bioinformatics team took a lower number of cases (54 cases) to overcome the learning curve compared to the NGS team (85 cases).

Conclusion

As NGS and bioinformatics lead precision oncology into the forefront of cancer management, characterizing the TAT of NGS and bioinformatics processes improves the timeliness of data output by potentially spotlighting problems early for rectification, thereby improving care delivery.

Minimally invasive liver resection for huge (≥10 cm) tumors: an international multicenter matched cohort study with regression discontinuity analyses

BACKGROUND

The application and feasibility of minimally invasive liver resection (MILR) for huge liver tumours (≥10 cm) has not been well documented.

METHODS

Retrospective analysis of data on 6,617 patients who had MILR for liver tumours were gathered from 21 international centers between 2009-2019. Huge tumors and large tumors were defined as tumors with a size ≥10.0 cm and 3.0-9.9 cm based on histology, respectively. 1:1 coarsened exact-matching (CEM) and 1:2 Mahalanobis distance-matching (MDM) was performed according to clinically-selected variables. Regression discontinuity analyses were performed as an additional line of sensitivity analysis to estimate local treatment effects at the 10-cm tumor size cutoff.

RESULTS

Of 2,890 patients with tumours ≥3 cm, there were 205 huge tumors. After 1:1 CEM, 174 huge tumors were matched to 174 large tumors; and after 1:2 MDM, 190 huge tumours were matched to 380 large tumours. There was significantly and consistently increased intraoperative blood loss, frequency in the application of Pringle maneuver, major morbidity and postoperative stay in the huge tumour group compared to the large tumour group after both 1:1 CEM and 1:2 MDM. These findings were reinforced in RD analyses. Intraoperative blood transfusion rate and open conversion rate were significantly higher in the huge tumor group after only 1:2 MDM but not 1:1 CEM.

CONCLUSIONS

MILR for huge tumours can be safely performed in expert centers It is an operation with substantial complexity and high technical requirement, with worse perioperative outcomes compared to MILR for large tumors, therefore judicious patient selection is pivotal.

The learning curve of laparoscopic liver resection utilising a difficulty score

BACKGROUND

This study aimed to quantitatively evaluate the learning curve of laparoscopic liver resection (LLR) of a single surgeon.

PATIENTS AND METHODS

A retrospective review of a prospectively maintained database of liver resections was conducted. 171 patients undergoing pure LLRs between April 2008 and April 2021 were analysed. The Halls difficulty score (HDS) for theoretical predictions of intraoperative complications (IOC) during LLR was applied. IOC was defined as blood loss over 775 mL, unintentional damage to the surrounding structures, and conversion to an open approach. Theoretical association between HDS and the predicted probability of IOC was utilised to objectify the shape of the learning curve.

RESULTS

The obtained learning curve has resulted from thirteen years of surgical effort of a single surgeon. It consists of an absolute and a relative part in the mathematical description of the additive function described by the logarithmic function (absolute complexity) and fifth-degree regression curve (relative complexity). The obtained learning curve determines the functional dependency of the learning outcome versus time and indicates several local extreme values (peaks and valleys) in the learning process until proficiency is achieved.

CONCLUSIONS

This learning curve indicates an ongoing learning process for LLR. The proposed mathematical model can be applied for any surgical procedure with an existing difficulty score and a known theoretically predicted association between the difficulty score and given outcome (for example, IOC).

Laparoscopic liver resection for huge (≥10 cm) hepatocellular carcinoma: A coarsened exact-matched single-surgeon study

INTRODUCTION

Laparoscopic liver resection (LLR) is increasingly being utilised worldwide for the management of both benign and malignant liver tumours. However, there is limited data to date regarding the safety and feasibility of this approach for huge (≥10 cm) hepatocellular carcinomas (HCCs). We present here our early experience performing LLR for huge HCCs.

METHODS

We conducted a retrospective review of 280 consecutive patients who underwent LLR by a single surgeon from 2012 to August 2020.15 patients had a preoperative radiological diagnosis of huge (≥10 cm) HCC. Coarsened exact-matched (CEM) weighting was used to compare them to 101 patients who underwent LLR for non-huge HCC.

RESULTS

After CEM-weighting, both groups were well-balanced for baseline variables. There was no difference in the rates of open conversion. The huge HCC patients had a higher mean Iwate difficulty score than the non-huge HCC patients (9.13 vs 6.53, p = 0.007). As such, the median operating time for the huge HCC group was longer (360 min vs 240min, p = 0.049). However, there were no significant differences in estimated blood loss, proportion of patients requiring blood transfusion, utilization of Pringle maneuver or median Pringle duration. Post-operatively, there were no significant differences in median LOS, overall and major morbidity rates, and 90-day mortality rates between both groups. Median resection margins were also similar for both cohorts.

CONCLUSION

LLR may be performed successfully for selected patients with huge HCC, with encouraging perioperative outcomes and no compromise in oncologic efficacy.

Comparison between short and long-term outcomes after minimally invasive versus open primary liver resections for hepatocellular carcinoma: A 1:1 matched analysis

BACKGROUND

This study aims to compare the short- and long-term outcomes of patients undergoing minimally invasive liver resection (MILR) versus open liver resection (OLR) for nonrecurrent hepatocellular carcinoma (HCC).

METHODS

Review of 204 MILR and 755 OLR without previous LR performed between 2005 and 2018. 1:1 coarsened exact matching (CEM) and 1:1 propensity-score matching (PSM) were performed.

RESULTS

Overall, 190 MILR were well-matched with 190 OLR by PSM and 86 MILR with 86 OLR by CEM according to patient baseline characteristics. After PSM and CEM, MILR was associated with a significantly longer operation time [230 min (interquartile range [IQR], 145-330) vs. 160 min (IQR, 125-210), p < .001] [215 min (IQR, 135-295) vs. 153.5 min (120-180), p < .001], shorter postoperative stay [4 days (IQR, 3-6) vs. 6 days (IQR, 5-8), p = .001)] [4 days (IQR, 3-5) vs. 6 days (IQR, 5-7), p = .004] and lower postoperative morbidity [40 (21%) vs. 67 (35.5%), p = .003] [16 (18.6%) vs. 27 (31.4%), p = .036] compared to OLR. MILR was also associated with a significantly longer median time to recurrence (70 vs. 40.3 months, p = .014) compared to OLR after PSM but not CEM. There was no significant difference in terms of overall survival and recurrence-free survival.

CONCLUSION

MILR is associated with superior short-term postoperative outcomes and with at least equivalent long-term oncological outcomes compared to OLR for HCC.

Learning curves in minimally invasive hepatectomy: systematic review and meta-regression analysis

BACKGROUND

Minimally invasive hepatectomy (MIH) has become an important option for the treatment of various liver tumours. A major concern is the learning curve required. The aim of this study was to perform a systematic review and summarize current literature analysing the learning curve for MIH.

METHODS

A systematic review of the literature pertaining to learning curves in MIH to July 2019 was performed using PubMed and Scopus databases. All original full-text articles published in English relating to learning curves for both laparoscopic liver resection (LLR), robotic liver resection (RLR), or a combination of these, were included. To explore quantitatively the learning curve for MIH, a meta-regression analysis was performed.

RESULTS

Forty studies relating to learning curves in MIH were included. The median overall number of procedures required in studies utilizing cumulative summative (CUSUM) methodology for LLR was 50 (range 25-58) and for RLR was 25 (16-50). After adjustment for year of adoption of MIH, the CUSUM-derived caseload to surmount the learning curve for RLR was 47.1 (95 per cent c.i. 1.2 to 71.6) per cent; P = 0.046) less than that required for LLR. A year-on-year reduction in the number of procedures needed for MIH was observed, commencing at 48.3 cases in 1995 and decreasing to 23.8 cases in 2015.

CONCLUSION

The overall learning curve for MIH decreased steadily over time, and appeared less steep for RLR compared with LLR.

Minimally invasive versus open right anterior sectionectomy and central hepatectomy for central liver malignancies: a propensity-score-matched analysis

BACKGROUND

The utility of minimally-invasive liver resection (MILR) for deep centrally located tumours (CLT) remains controversial. We aimed to review our institution's experience and outcomes with minimally invasive central hepatectomy (CH) and right anterior sectionectomy (RAS) for CLT in a propensity score-matched (PSM) analysis.

METHODS

Retrospective review of a prospectively maintained surgical database revealed 23 patients who underwent MILR (6 CH, 17 RAS) and 53 patients who underwent open liver resection (OLR; 24 CH, 29 RAS) for CLT. PSM in a 1:1 ratio identified two groups of patients with similar baseline clinicopathological characteristics. Peri-operative outcomes were then compared.

RESULTS

There was one laparoscopic-assisted, one robot-assisted and two laparoscopic-converted-open procedures in the MILR cohort. Across the unmatched cohort, there was only one mortality (MILR) and five patients with major morbidity (all OLR). MILR was associated with a longer operating time (P < 0.001), but shorter post-operative hospital stay (P = 0.002) and decreased morbidity (P = 0.018) in the unmatched cohort. Examination of peri-operative outcomes after PSM revealed that MILR was similarly associated with a longer operating time (P = 0.001) and shortened post-operative hospital stay (P = 0.043). OLR was associated with a significantly reduced application of Pringle manoeuvre (P = 0.004). There were no significant differences between MILR and OLR with regards to blood loss, blood transfusions, morbidity and margin status in the PSM analysis.

CONCLUSION

MILR for CLT is safe and feasible when performed by experienced surgeons. It is associated with shorter hospital stays but at the expense of longer operation times and more frequent application of Pringle manoeuver.

Analysis of perioperative outcomes following laparoscopic repeat liver resection compared to laparoscopic primary liver resection based on a single surgeon's experience: A 1:2 propensity score-matched study

BACKGROUND

We report a single surgeon experience with laparoscopic repeat liver resection (LRLR), and analyse short-term outcomes relative to laparoscopic primary liver resection (LPLR).

METHODS

Two-hundred and twenty-two laparoscopic liver resections were performed from 2012 to 2019 of which 33 were LRLR. 1:2 propensity-score matching was done to compare 32 LRLR with 64 LPLR cohort. We further analyzed the first 16 LRLR cases compared to the subsequent 17 cases.

RESULTS

32 LRLR cases were matched to 64 LPLR cases. Apart from a higher frequency of Pringle maneuver in the LPLR cohort (p = 0.006), there were no differences in other perioperative outcomes. There were more posterosuperior located tumours (75.0% vs 17.6%, p = 0.003) and higher median difficulty score (8.50 vs 5.00, p = 0.025) in the initial 16 LRLR cases compared to the next 17. The earlier group had higher median blood loss (250.00 ml vs 50.00 ml, p = 0.012), but other outcomes were similar.

CONCLUSION

LRLR may be safely performed in selected patients with no difference in key perioperative outcomes compared to LPLR.

Adoption of Robotic Liver, Pancreatic and Biliary Surgery in Singapore: A Single Institution Experience with Its First 100 Consecutive Cases

Introduction: Presently, robotic hepatopancreatobiliary surgery (RHPBS) is increasingly adopted worldwide. This study reports our experience with the first 100 consecutive cases of RHPBS in Singapore. Methods: Retrospective review of a single-institution prospective database of the first 100 consecutive RHPBS performed over 6 years from February 2013 to February 2019. Eighty-six cases were performed by a single surgeon. Results: The 100 consecutive cases included 24 isolated liver resections, 48 pancreatic surgeries (including 2 bile duct resections) and 28 biliary surgeries (including 8 with concomitant liver resections). They included 10 major hepatectomies, 15 pancreaticoduodenectomies, 6 radical resections for gallbladder carcinoma and 8 hepaticojejunostomies. The median operation time was 383 minutes, with interquartile range (IQR) of 258 minutes and there were 2 open conversions. The median blood loss was 200ml (IQR 350ml) and 15 patients required intra-operative blood transfusion. There were no post-operative 90-day nor in-hospital mortalities but 5 patients experienced major (> grade 3a) morbidities. The median post-operative stay was 6 days (IQR 5 days) and there were 12 post-operative 30-day readmissions. Comparison between the first 50 and the subsequent 50 patients demonstrated a significant reduction in blood loss, significantly lower proportion of malignant indications, and a decreasing frequency in liver resections performed. Conclusion: Our experience with the first 100 consecutive cases of RHPBS confirms its feasibility and safety when performed by experienced laparoscopic hepatopancreatobiliary surgeons. It can be performed for even highly complicated major hepatopancreatobiliary surgery with a low open conversion rate. Keywords: Biliary surgery, hepaticojejunostomy, liver resection, pancreas, pancreaticoduodenectomy

Critical Appraisal of the Impact of Individual Surgeon Experience on the Outcomes of Minimally Invasive Distal Pancreatectomies: Collective Experience of Multiple Surgeons at a Single Institution

BACKGROUND

Presently, there are limited studies analyzing the learning experience of minimally invasive distal pancreatectomies (MIDPs) and these frequently focused on a single surgeon or institution learning curve. This study aims to critically analyze the impact of individual surgeon experience on the outcomes of MIDP based on the collective experiences of multiple surgeons at a single institution.

METHODS

A retrospective review of 90 consecutive MIDP from 2006 to 2018 was performed. These cases were performed by 13 surgeons over various time periods. The cohort was stratified into 4 groups according to individual surgeon experience. The case experience of these surgeons was as follows: <5 cases (n=8), 6 to 10 cases (n=2), 11 to 15 cases (n=2), and 30 cases (n=1).

RESULTS

The distribution of the 90 cases were as follows: experience <5 cases (n=44), 6 to 10 cases (n=20), 11 to 15 cases (n=11), and 15 cases (n=15). As individual surgeons gained increasing experience, this was significantly associated with increasingly difficult resections performed, increased frequency of the use of robotic assistance and decreasing open conversion rates (20.5% vs. 100% vs. 9.1% vs. 0%, P=0.038). There was no significant difference in other perioperative outcomes. These findings suggest that the outcomes of MIDP in terms of open conversion rate could be optimized after 15 cases. Subset analyses suggested that the learning curve for MIDP of low difficulty was only 5 cases.

CONCLUSION

MIDP can be safely adopted today and the individual surgeon learning curve for MIDP of all difficulties in terms of open conversion rate can be overcome after 15 cases.