Development Process and Technical Aspects of Laparoscopic Hepatectomy: Learning Curve Based on 15 Years of Experience

Prognosis of a Heterogeneous TRG Pathological Response to Neoadjuvant Chemotherapy in Patients who Undergo Resection for Colorectal Liver Metastases

BACKGROUND

Optimal management of colorectal liver metastasis (CRLM) is based on a combination of chemotherapy and surgical resection. The tumor regression grade (TRG) score is a histological scoring system to evaluate response to chemotherapy. The prognosis of a heterogeneous response in cases of multiple metastases has not been evaluated according to the TRG score.

PATIENTS AND METHODS

All patients who underwent liver resection for multiple CRLM after neoadjuvant chemotherapy in two tertiary centers from January 2015 to April 2019 were retrospectively included. Oncological characteristics and outcome between TRG 1-2-3 (good response group), TRG 4-5 (poor response group) and heterogeneous TRG (good and poor TRG among different lesions within the same patient) groups were compared.

RESULTS

Among the 327 patients included, 134 (41.0%) had good response (TRG 1-2-3), 120 (36.7%) had poor response (TRG 4-5), and 73 (22.3%) had heterogeneous response. The type and number of cycles of chemotherapy, k-Ras mutational status, and tumor number or size did not differ between the three groups. Use of irinotecan-based and anti-VEGF neoadjuvant therapy was associated with better TRG response [irinotecan-based: hazard ratio (OR) = 1.744; p = 0.045; anti-VEGF neoadjuvant therapy: 2.054; p = 0.005). Overall survival (OS) was higher in the 1-2-3 TRG group than in the heterogeneous TRG group (2-year OS = 81.3% vs. 60.3%, respectively; p = 0.003) and the 4-5 TRG group (2-year OS = 81.3% vs. 55.0%, respectively; p = 0.012) and similar between the heterogeneous and 4-5 TRG groups.

CONCLUSIONS

The proportion of heterogeneous pathological response according to TRG is 22.3%, and the prognosis is comparable to that of poor pathological response.

Open Versus Laparoscopic Right Hepatectomy for Hepatocellular Carcinoma Following Sequential TACE-PVE: A Multicentric Comparative Study

BACKGROUND

Right hepatectomy (RH) for hepatocellular carcinoma (HCC) is ideally preceded by transcatheter arterial chemoembolization (TACE) and portal vein embolization (PVE). Laparoscopic approach improves short-term outcome and textbook outcome (TO), which reflects the "ideal" surgical outcome, after RH. However, laparoscopic RH on an underlying diseased liver and after TACE/PVE remains a challenging procedure. The aim of this study was to compare the outcomes in patients who underwent laparoscopic liver resection (LLR) or open liver resection (OLR) following TACE/PVE.

PATIENTS AND METHODS

All patients with HCC who underwent RH after TACE/PVE in five French centers were retrospectively included. Outcomes were compared between the LLR group and the OLR group using propensity score matching (PSM). Quality of surgical care was defined by TO.

RESULTS

Between 2005 and 2019, 117 patients were included (41 in LLR group, 76 in OLR group). Overall morbidity was comparable (51% versus 53%, p = 0.24). In LLR group, TO was completed in 66% versus 37% in OLR group (p = 0.02). LLR and absence of clamping were the only factors associated with TO completion [hazard ratio (HR) 4.27, [1.77-10.28], p = 0.001]. After PSM, 5-year overall survival (OS) and progression-free survival (PFS) were 55% in matched LLR versus 77% in matched OLR, p = 0.35, and 13% in matched LLR versus 17% in matched OLR, p = 0.97. TO completion was independently associated with a better 5-year OS (65.2% versus 42.5%, p = 0.007).

CONCLUSION

Major LLR after TACE/PVE should be considered as a valuable option in expert centers to increase the chance of TO, the latter being associated with a better 5-year OS.

Laparoscopic versus open liver resections for intrahepatic cholangiocarcinoma and gallbladder cancer: the Mayo clinic experience

BACKGROUND

Data regarding laparoscopic liver resections(LLRs) for Gallbladder cancer(GBC) and Intrahepatic Cholangiocarcinoma(iCCA) are sparse. This study compared LLRs with open liver resections(OLRs) in a high-volume center.

METHODS

Data of patients who underwent LLR or OLR for GBC or iCCA at Mayo-Clinic between 01/2016 and 04/2021 were retrospectively compared. Proportional hazards models were used to compare the approach on survival.

RESULTS

32 and 52 patients underwent LLR and OLR during the study period, respectively. 64 and 20 patients had iCCA and GBC, respectively. LLR had lower median blood loss (250 mL vs. 475 mL, p = 0.001) and shorter median length of stay compared to OLR (3.0 days vs. 6.0 days, p = 0.001). LLR and OLR did not differ in post-operative major complication (25% vs. 32.7%, p = 0.62), negative margin (100% vs. 90.4%, p = 0.15) and completeness of lymphadenectomy rates (36.8% vs. 45.5%, p = 0.59). The median number of harvested lymph node was 4.0 and 5.0 for LLR and OLR, respectively (p = 0.347). There were no associations between approach and 3-year overall and disease-free survival between LLR and OLR (49.8% vs. 63.2% and 39.6% vs. 21.5%, p = 0.66 and p = 0.69).

DISCUSSION

With appropriate patient selection and when compared to OLRs, LLRs for GBC and iCCA are feasible, safe and offer potential short-term benefits without compromising on oncological resection principals and long-term outcomes.

Clinical application of regional and intermittent hepatic inflow occlusion in laparoscopic hepatectomy

Aim

The aim of this study is to investigate the advantages and disadvantages of regional and intermittent hepatic inflow occlusion in laparoscopic hepatectomy.

Methods

The clinical data of 180 patients who underwent laparoscopic liver surgery in Taizhou People’s Hospital from 2015 to 2021 were analyzed retrospectively. The patients were divided into the regional occlusion group (n = 74) and the Pringle’s maneuver occlusion group (n = 106) according to the technique used in the intraoperative hepatic inflow occlusion. The pre- and intra-operative indicators, postoperative recovery indicators, and complications of the two groups were compared.

Results

There were no significant differences (p > 0.05) between the groups in terms of sex, age, preoperative alanine aminotransferase (ALT), preoperative aspartate aminotransferase (AST), preoperative albumin, alpha-fetoprotein, liver cirrhosis, hepatitis B, tumor location, gas embolism, intraoperative blood transfusion, postoperative albumin, postoperative total bilirubin (TBIL), postoperative hospital stays, and complications. The preoperative TBIL and operation time were higher in the regional occlusion group than in the Pringle’s maneuver occlusion group, while the amount of intraoperative bleeding, postoperative ALT, and AST in the regional occlusion group were significantly lower than those in the Pringle’s maneuver occlusion group (p < 0.05).

Conclusion

The two occlusion techniques are equally safe and effective, but regional hepatic inflow occlusion is more advantageous in operation continuity, intraoperative bleeding, and postoperative liver function recovery. The long duration and high precision of the regional blood flow occlusion technique demands a more experienced physician with a higher level of operation; therefore, it can be performed by experienced laparoscopic liver surgeons.

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

Standardized Technique of Selective Left Liver Vascular Exclusion During Laparoscopic Liver Resection for Benign and Malignant Tumors

BACKGROUND

Tumors located close to major hepatic veins pose a technical challenge to standard laparoscopic liver resection. Hepatic outflow occlusion may reduce the risks of bleeding from hepatic vein and gas embolism. The aim of this study was to detail our standardized laparoscopic approach for a safe extrahepatic control of the common trunk of middle and left hepatic veins during laparoscopic liver resection and to assess its feasibility in patients with tumors located in both right and left lobes of the liver.

METHODS

Data of 25 consecutive patients who underwent laparoscopic liver resection with extrahepatic control of the common trunk of middle and left hepatic veins were reviewed.

RESULTS

All patients underwent primary hepatectomy. The vast majority (84%) of patients had malignant tumors. The control of the common trunk of middle and left hepatic veins was achieved in 96% of patients. There were 14 (56%) major hepatectomies and 11 (44%) minor hepatectomies. Some form of vascular clamping was performed in 23 (62%) patients: Pringle maneuver in 17 (median time = 45 min; range, 10-109) and selective vascular exclusion of the liver in 6 patients (median time = 30 min; range, 15-94). The median duration of operation was 254 min (range, 70-441). There was one case (4%) of gas embolism but without any complications during the postoperative course. Conversion to open surgery was performed in 2 (7.7%) patients: 1 for oncologic reason and 1 for non-progression during the transection plane. Perioperative blood transfusion rate was nil. The overall morbidity rate was 24%.

CONCLUSIONS

The laparoscopic approach for an extrahepatic control of the common trunk of middle and left hepatic veins is reproducible, safe, and effective, and can be applied during laparoscopic liver resection for tumors close to major hepatic veins.

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).

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.

Learning process of laparoscopic liver resection and postoperative outcomes: chronological analysis of single-center 15-years' experience

BACKGROUND

Limited studies have reported the actual learning process of laparoscopic liver resection (LLR). This study aimed to chronologically evaluate our 15 years' experience of LLR.

METHODS

All consecutive LLRs between 2006 to 2020 were retrospectively analyzed. The time period was divided into three groups; first (2006-2010), second (2011-2015), and third (2016-2020) period. The primary endpoint of this study was a composite of overall (Clavien-Dindo grade ≥ II) or major (grade ≥ IIIa) postoperative complications within 30 days. Using the IWATE criteria (four difficulty levels based on six indices), LLR was categorized as basic (< 7 points) and advanced (≥ 7 points) one. All analyses were performed based on the intention-to-treat principles.

RESULTS

During the study period, a total of 382 LLRs were gradually performed (first period, n = 54; second period, n = 114, and third period, n = 214). Low incidences of overall and major complications were maintained (9.3, 10.5, and 7.0%, p = 0.514, and 1.9, 2.6, and 2.3%, p = 1.000). Meanwhile, pure LLRs (i.e., LLRs without hand-assisted or hybrid approach) and advanced LLRs were increasingly performed in 25 (46.3%), 71 (62.3%), and 205 (95.8%) patients (p < 0.001) and 3 (5.6%), 18 (15.8%), and 58 (27.1%) patients (p < 0.001), respectively.

CONCLUSIONS

This study suggests that stepwise approach from basic to advanced procedures and use of hand-assisted or hybrid approach during the early phases for starting LLR practice may allow for maintaining low morbidity in specialized center.

Unravelling the Complexity Myth for Minimally Invasive Right Hepatectomy: Liver Parenchymal Features and their Correlation to Objective Outcomes in Major Anatomical Resections

BACKGROUND

Minimally invasive approaches to major liver resection have been limited by presumed difficulty of the operation. While some concerns arise from mastering the techniques, factors such as tumor size and liver parenchymal features have anecdotally been described as surrogates for operative difficulty. These factors have not been systematically studied for minimally invasive right hepatectomy (MIRH).

METHODS

Seventy-five patients who underwent MIRH during 2007-2016 by the senior author were evaluated; these were compared to control group of open right hepatectomy. Demographics, operative, and post-operative variables were collected. Operative times and estimated blood loss, two objective parameters of operative difficulty were correlated to volume of hepatic resection, parenchymal transection diameter and liver parenchymal features using regression analysis.

RESULTS

Thirty-eight (50.6%) resections were performed for malignant indications. Average tumor size was 5.7 cm (±3.6), mean operative time was 196 min (±74), and mean EBL was 220 mL (±170). Average transection diameter was 10.1 cm (±1.7). There was no correlation between operative difficulty with parenchymal transection diameter or presence of steatosis. Blood loss was higher with increased right hepatic lobe volume and body mass index.

CONCLUSIONS

This analysis of a very defined anatomical resection suggests that the often quoted radiographic and pathologic features indicative of a challenging procedure were not significant in determining operative difficulty.

Operative Time, Age, and Serum Albumin Predict Surgical Morbidity After Laparoscopic Liver Surgery

Background. Laparoscopic liver resection (LLR) has emerged as a considerable alternative to conventional liver surgery. However, the increasing complexity of liver resection raises the incidence of postoperative complications. The aim of this study was to identify risk factors for postoperative morbidity in a monocentric cohort of patients undergoing LLR. Methods. All consecutive patients who underwent LLR between 2015 and 2019 at our institution were analyzed for associations between complications with demographics and clinical and operative characteristics by multivariable logistic regression analyses. Results. Our cohort comprised 156 patients who underwent LLR with a mean age of 60.0 ± 14.4 years. General complications and major perioperative morbidity were observed in 19.9% and 9.6% of the patients, respectively. Multivariable analysis identified age>65 years (HR = 2.56; P = .028) and operation time>180 minutes (HR = 4.44; P = .001) as significant predictors of general complications (Clavien ≥1), while albumin<4.3 g/dl (HR = 3.66; P = .033) and also operative time (HR = 23.72; P = .003) were identified as predictors of major postoperative morbidity (Clavien ≥3). Conclusion. Surgical morbidity is based on patient- (age and preoperative albumin) and procedure-related (operative time) characteristics. Careful patient selection is key to improve postoperative outcomes after LLR.

Surgical Management of Hepatic Benign Disease: Have the Number of Liver Resections Increased in the Era of Minimally Invasive Approach? Analysis from the I Go MILS (Italian Group of Minimally Invasive Liver Surgery) Registry

BACKGROUND

Increased expertise with minimally invasive liver surgery (MILS) could cause an unjustified extension of indications to resect liver benign disease (BD). The aim of this study was to evaluate the operative risk of MILS for BD and if implementation and diffusion of MILS have widened indications for BD resection.

METHODS

A prospective study including centers with > 6 MILS for BD, enrolled in the I Go MILS registry from January 2015 to October 2016. Cysts fenestrations were excluded.

RESULTS

Eight hundred eighteen MILS were performed in 15 centers. One hundred seventy-three of these (21.1%) were for BD: conversion rate was 6.9%, postoperative mortality and morbidity rates were 0 and 13.9%. During the same period, 3713 liver resections (open + MILS) were performed and 407 (11.0%) were for BD. A time-trend analysis showed that the total number of MILS and the number of MILS for malignant disease significantly increased, but this increasing trend was not documented for the number of MILS for BD, which remained stable during the study period of time. This trend was confirmed for the overall rate of resected BD (open + MILS) that remained stable.

DISCUSSION

BD represents a valid indication for MILS. For BD, 21.1% of MILS was performed, rate significantly lower than that previously reported in Italy. Although an evident growth of the use of MILS was observed during the time period analysis in Italy, this trend did not correspond to an increased number of MILS for BD, and the overall rate of resected BD was comparable to that reported in previous large open series.

Surgical Glove Technique for Laparoscopic Liver Resection

BACKGROUND

Liver tumors located in segments 7 and 8 pose a technical challenge to standard laparoscopic liver resection. Intraoperative placement of a surgical glove behind the right liver after the right triangular ligament and coronary ligament are divided facilitates liver exposure during parenchymal transection and control of the bleeding at the deeper part of the parenchymal plane. The aim of this study was to describe our standardized technique in detail and to assess the feasibility of this technique in patients with different clinical backgrounds and clarify the limits of this technique.

METHODS

Medical records of 20 consecutive patients considered for laparoscopic liver resection using the surgical glove technique were reviewed.

RESULTS

All patients had malignant disease and the vast majority of patients had colorectal metastatic tumors. Overall, 65% of patients had tumors located in segment 8. Placing the surgical water glove could be achieved without complication in all 20 patients. One surgical glove was used in this series (usually size 6.5 to 7.5 is an adequate size). Time for preparing the surgical green water glove was estimated to be less than 1 min. The mean duration of operation ranged from 136 to 332 min (median, 240 min). Intermittent Pringle's maneuver was applied in all patients with a median time of 33 min. No additional intercostal trocars were required. There was no intraoperative blood transfusion or conversion to open surgery. The median maximum size of the tumor was 23 mm. There was no operative mortality. Overall morbidity was 30%. Surgical margins were negative in 80% of patients.

CONCLUSIONS

The surgical glove technique is easy, reproducible, effective, and safe and can be applied to both laparoscopic and robotic liver resection.

Stepwise development of laparoscopic liver resection skill using rubber traction technique

BACKGROUND

To improve patient safety, we standardized our surgical technique and implemented a stepwise strategy for surgeons learning to perform laparoscopic liver resection (LLR). The aim of the study is to describe how the stepwise training approach and standardized LLR affects surgical outcomes.

METHODS

Data from 272 consecutive patients who underwent LLR from January 2009 to December 2017 were retrospectively reviewed. The risk-adjusted cumulative sum (RA-CUSUM) of surgical failures (conversion to laparotomy, blood transfusion, or Clavien-Dindo grade ≥3) and the CUSUM of operative time were used to determine optimal number of operations needed to achieve the best surgical outcome.

RESULTS

As the surgeon moved from simple to complex procedures, the complication rates, need for transfusions, and conversion rates did not increase over time. After 53 cases of minor LLR, a learning curve of 21 cases was achieved for right hepatectomy. Blood loss and operative time significantly improved thereafter. For minor anterolateral and posterosuperior segment resections, blood loss, and operative time significantly improved at the 37th and 31st case, respectively, given that the anterolateral segments had more complex surgeries performed.

CONCLUSION

Standardization of the operative technique and the implementation of a stepwise approach to training surgeons to perform LLRs could considerably improve surgical outcomes.

Learning Curve in Laparoscopic Liver Resection, Educational Value of Simulation and Training Programmes: A Systematic Review

BACKGROUND

The laparoscopic approach is widely accepted as the procedure of choice for abdominal surgery. However, laparoscopic liver resection (LLR) has advanced slowly due to the significant learning curve (LC), and only few publications have dealt with advanced training in LLR.

METHODS

Two reviewers conducted systematic research through MEDLINE and EMBASE with combinations of the following keywords: (learning curve OR teaching OR training OR simulation OR education) AND (liver OR hepatic) AND (laparoscopic OR laparoscopy). Robotic-assisted, hand-assisted and hybrid LLRs were excluded.

RESULTS

Nineteen studies were retrieved. Overall, the level of evidence was low. Thirteen articles assessed the LC during real-life LLR, and six articles focussed on simulation and training programmes in LLR. The LC in minor LLR comprised 60 cases overall, and 15 cases for standardised left lateral sectionectomy. For major LLR (MLLR), the LC was 50 cases for most studies, but was reported to be 15-20 cases in more recent studies, provided MLLR is performed progressively in selected patients. However, there was heterogeneity in the literature regarding the number of minor LLRs required before MLLR, with 60 minor LLRs reported as the minimum. Six studies showed a potential benefit of simulation and training programmes in this field. The gradual implementation of LLR combined with simulation-based training programmes could reduce the clinical impact of LC.

CONCLUSIONS

The LC in LLR is a long process, and MLLR should be gradually implemented under the supervision of experienced surgeons. Training outside the operating room may reduce the LC in real-life situations.

Impact of Surgeon Volume on Outcomes and Expenditure Among Medicare Beneficiaries Undergoing Liver Resection: the Effect of Minimally Invasive Surgery

BACKGROUND

Although the role of annual surgeon volume on perioperative outcomes after liver resection (LR) has been investigated, there is a paucity of data regarding the impact of surgeon volume on outcomes of minimally invasive LR (MILR) versus open LR (OLR).

METHODS

Patients undergoing LR between 2013 and 2015 were identified in the Medicare inpatient Standard Analytic Files. Patients were classified into three groups based on surgeons' annual caseload: low (≤ 2 cases), medium (3-5 cases), or high (≥ 6 cases). Short-term outcomes and expenditures of LR, stratified by surgeon volume and minimally invasive surgery (MIS), were examined.

RESULTS

Among 3403 surgeons performing LR on 7169 patients, approximately 90% of surgeons performed less than 5 liver resections per year for Medicare patients. Only 7.1% of patients underwent MILR (n = 506). After adjustment, the likelihood of experiencing a complication and death within 90 days decreased with increasing surgeon volume. Outcomes of open and MILR among low- or high-volume surgeon groups, including rates of complications, 30- and 90-day readmission and mortality were similar. However, the difference of average total episode payment between open and MIS was higher in the high-volume surgeon group (low volume: $2929 vs. medium volume: $2333 vs. high volume: $7055).

CONCLUSION

Annual surgeon volume was an important predictor of outcomes following LR. MILR had comparable results to open LR among both the low- and high-volume surgeons.

Evaluating the learning curve for laparoscopic liver resection: a comparative study between standard and learning curve CUSUM

BACKGROUND

Laparoscopic liver resection (LLR) requires training in both hepatobiliary surgery and advanced laparoscopy. Available data on LLR learning curves are derived from pioneer surgeons. The aims of this study were to evaluate the LLR learning curve for second generation surgeons, and to compare different CUSUM methodology with and without risk adjustment.

METHODS

Retrospective analysis of a prospective database of 111 consecutive patients who underwent LLR by two surgeons at a single centre between 2011 and 2016. The LLR learning curve for minor hepatectomy (MH) was evaluated for each surgeon using standard CUSUM before and after risk-adjusting for operative difficulty using the Iwate index, and compared with Learning Curve (LC) CUSUM. The end points were operative time and conversion rate.

RESULTS

Standard CUSUM analysis identified a learning curve of 50-60 MH procedures. The corresponding learning curve reduced to 25-30 after risk-adjusting for operative difficulty, whilst LC-CUSUM identified a learning curve of 17-25 procedures.

CONCLUSIONS

The learning curve for laparoscopic minor liver resection by second generation surgeons is shorter than that for pioneer surgeons. Laparoscopic HPB fellowship programmes may further shorten the learning curve, facilitating safe expansion of LLR. The LC-CUSUM method is an alternative technique that warrants further study.

Laparoscopic Liver Resection: Experience of 436 Cases in One Center

BACKGROUND

To report experience of laparoscopic liver resection (LLR) in one center.

METHODS

We retrospectively reviewed 436 consecutive LLRs in 411 patients between December 2010 and December 2016. On the basis of the 2008 Louisville Statement, we divided the 436 cases into two groups: Simple Group (n = 203) and Difficult Group (n = 233).

RESULTS

The indications were HCC (n = 194), colorectal cancer liver metastasis (n = 156), benign tumors (n = 62), hepatolithiasis (n = 2), and other malignant lesions (n = 22). The median tumor size was 24 mm (range 3 to 130). Procedures of LLR included wedge resection (n = 230), one segmentectomy (n = 8), two segmentectomies (n = 12), left lateral sectionectomy (n = 75), right hepatectomy (n = 52), left hepatectomy (n = 31), extended right hepatectomy (n = 2), extended left hepatectomy (n = 5), central bisectionectomy (n = 3), right posterior sectionectomy (n = 12), and right anterior sectionectomy (n = 6). The median operative time was 228 min (range 9-843) and median blood loss was 150 ml (range 2-3500). Twenty-five cases required blood transfusion (5.7%). Conversion to open surgery was required in six cases (1.4%). The mean length of stay was 6.4 ± 2.9 days. Overall complication rate was 9.4% and major complication rate was 5%. One patient died of liver failure on the thirtieth postoperative day after a right hepatectomy. We had higher median blood loss (200 vs. 100 ml; p < 0.001), higher transfusion rate (8.2 vs. 2.9%; p = 0.020), longer median operative time (297 vs. 164 min; p < 0.001), higher conversion rate (2.6 vs. 0%; p = 0.021), higher complication rate (14.2 vs. 3.9%; p < 0.001), and longer mean postoperative hospital stay (6.8 ± 2.9 vs. 5.9 ± 3.0 days; p < 0.001) in the Difficult Group.

CONCLUSIONS

Laparoscopic liver resection is safe for selected patients in the Difficult Group. On the basis of the 2008 Louisville Statement, selection criteria of LLR are helpful to predict the difficulty of the operation and the postoperative outcomes of LLR.

Laparoscopic versus open two-stage hepatectomy for bilobar colorectal liver metastases: A bi-institutional, propensity score-matched study

BACKGROUND

The safety and feasibility of laparoscopic, two-stage hepatectomy for bilobar colorectal liver metastases is poorly evaluated.

METHODS

We reviewed retrospectively 86 consecutive patients who underwent complete two-stage hepatectomy (left lobe clearance as the first stage and standard/extended right hepatectomy as the second stage) for bilobar colorectal liver metastases between 2007 and 2017 in 2 tertiary centers. Short- and long-term outcomes were compared between laparoscopic and open two-stage hepatectomy before and after propensity score matching.

RESULTS

Laparoscopic two-stage hepatectomy was performed in 38 patients and open two-stage hepatectomy in 48. After propensity score matching, 25 laparoscopic and 25 open patients showed similar preoperative characteristics. For the first stage, a laparoscopic approach was associated with lesser hospital stays (4 vs 7.5 days; P < .001). For the second stage, a laparoscopic approach was associated with less blood loss (250 vs 500 mL; P = .040), less postoperative complications (32% vs 60%; P = .047), lesser hospital stays (9 vs 16 days; P = .013), and earlier administration of chemotherapy (1.6 vs 2 months; P = .039). Overall survival, recurrence-free survival, and liver-recurrence-free survival were comparable between the groups (3-year overall survival: 80% vs 54%; P = .154; 2-year recurrence-free survival: 20% vs 18%; P = .200; 2-year liver-recurrence-free survival: 39% vs 33%; P = .269). Although both groups had comparable recurrence patterns, repeat hepatectomies for recurrence were performed more frequently in the laparoscopic two-stage hepatectomy group (56% vs 0%; P = .006).

CONCLUSION

Laparoscopic two-stage hepatectomy for bilobar colorectal liver metastases is safe and feasible with favorable surgical and oncologic outcomes compared to open two-stage hepatectomy.

A stepwise learning curve to define the standard for technical improvement in laparoscopic liver resections: complexity-based analysis in 1032 procedures

The objective of this study is to define the learning curve in a series of procedures grouped according to their complexity calculated by difficulty index to define a standard for technical improvement. 1032 laparoscopic liver resections performed in a single tertiary referral center were stratified by difficulty scores: low difficulty (LD, n = 362); intermediate difficulty (ID, n = 332), and high difficulty (HD, n = 338). The learning curve effect was analyzed using the cumulative sum (CUSUM) method taking into consideration the expected risk of conversion. The ratio of laparoscopic/total liver resections increased from 5.8% (2005) to 71.1% (2018). The CUSUM analysis per group showed that the average value of the conversion rate was reached at the 60th case in the LD Group and at the 15th in the ID and HD groups. The evolution from LD to ID and HD procedures occurred only when learning curve in LD resections was concluded. Reflecting different degree of complexity, procedures showed significantly different blood loss, morbidity, and conversions among groups. A standard educational model-stepwise and progressive-is mandatory to allow surgeons to define the technical and technological backgrounds to deal with a specific degree of difficulty, providing a help in the definition of indications to laparoscopic approach in each phase of training.

Minimally invasive liver resection in the era of robotics: analysis of 214 cases

BACKGROUND

Minimally Invasive Liver Resection (MILR) techniques range from a hybrid-technique to full robotic approaches. When compared with open techniques, MILR has been shown to be advantageous by reducing pain, complications, length of stay and blood loss. The aim of this study was to compare clinical outcomes and hospital resource utilization between full laparoscopic, hand-assisted, and robotic liver resections among major (≥ 3 segments) and minor (≤ 2 segments) resections.

METHODS

A single-center comparative retrospective review was completed on 214 patients undergoing full laparoscopic, hand-assisted, or robotic liver resection procedures between 2005 and 2018.

RESULTS

Among minor resections: 85 full laparoscopic, 40 hand-assisted, and 35 robotic liver resection cases were analyzed; and among major resections: 13, 33, and 8 cases were analyzed, respectively. In the adjusted subgroup analysis of minor resections, OR time was significantly longer for the minor hand-assisted group ([Formula: see text] = 181 min; p < 0.05), and the average lesion size was smaller for the minor full laparoscopic group ([Formula: see text] = 4.2 cm; p < 0.05). Overall, direct hospital charges were lowest in the group of patients who underwent a minor resection using the full laparoscopic technique ([Formula: see text] = $39,054.90; p < 0.05), compared to the robotic technique. Due to the smaller sample size (n = 54) in the major resection subgroup, only two significant observations were made - the full laparoscopic group had the least amount of blood loss ([Formula: see text] = 227 cc; p < 0.05) and incurred the least amount of room and board charges compared to the other two techniques.

CONCLUSIONS

The robotic approach appears favorable for minor resections as evidenced by shorter length of stay but more costly than full laparoscopy. Clinical outcomes appear to be more dependent upon the magnitude of the resection (i.e. major vs. minor) than the MILR technique chosen. Randomized trials may be indicated to discern the best indications and advantages of each technique.

Enhanced Recovery in Liver Transplantation: A Feasibility Study

BACKGROUND

Enhanced Recovery After Surgery (ERAS) programmes after surgery are effective in reducing length of stay, functional recovery and complication rates in liver surgery (LS) with the indirect advantage of reducing hospitalisation costs. Preoperative comorbidities, challenging surgical procedures and complex post-operative management are the points that liver transplantation (LT) shares with LS. Nevertheless, there is little evidence regarding the feasibility and safety of ERAS programmes in LT.

METHODS

We designed a pilot, small-scale, feasibility study to assess the impact on hospital stay, protocol compliance and safety of an ERAS programme tailored for LT. The ERAS arm was compared with a 1:2 match paired control arm with similar characteristics. All patients with MELD <25 were included. A dedicated LT-tailored protocol was derived from publications on ERAS liver surgery.

RESULTS

Ten patients were included in the Fast-Trans arm. It was observed a 47% reduction of the total LOS, as compared to the control arm: 9.5 (9.0-10.5) days versus 18.0 (14.3-24.3) days, respectively, p <0.001. The protocol achieved 72.9% compliance. No differences were observed in terms of post-operative complications or readmission rates after discharge between the two arms. Overall, it was observed a reduction of length of stay in ICU and surgical ward in the Fast-Trans arm compared with the control arm.

CONCLUSION

Considered the main points in common between LS and LT, this small-scale study suggests that the application of an ERAS programme tailored to the LT setting is feasible. Further testing will be appropriate to generalise these findings.

Laparoscopic Right Hepatectomy for Hepatocellular Carcinoma: A Propensity Score Matching Analysis of Outcomes Compared with Conventional Open Surgery

BACKGROUND

The application of laparoscopic hepatectomy is gaining momentum. However, the safety and efficacy of laparoscopic right hepatectomy (LRH) on hepatocellular carcinoma (HCC) are yet to be adequately evaluated. We aimed to assess the surgical and oncological outcomes of LRH for HCC by comparing it with open right hepatectomy (ORH).

MATERIALS AND METHODS

Data of patients who underwent hepatectomy for HCC from May 2007 to January 2018 in our hospital were obtained. Baseline characteristics, postoperative recovery, and survival outcomes were compared. One-to-one propensity score matching (PSM) was used to minimize selection biases by balancing factors, including age, sex, preoperative therapy, tumor size, and pattern.

RESULTS

The original cohort included 109 patients (LRH, 41 patients; ORH, 68 patients). Of the 41 patients who underwent LRH, 8 patients (19.5%) required conversion to laparotomy. The overall morbidity was 19.5%, and no mortality in LRH was noted. After PSM, LRH was associated with a tendency of prolonged operative time (255.5 ± 93.4 minutes versus 225.9 ± 39.8 minutes, P = .08) and less intraoperative blood loss [300 (100-1200) versus 500 (200-2000) mL, P < .01]. LRH showed up a trend of less overall morbidity without statistical significance (18.4% versus 26.3%, P = .41). Moreover, the 3-year overall and disease-free survival did not differ significantly between the groups during a median follow-up of 19 (3-58) months for the LRH group and 23 (3-97) months for the ORH group.

CONCLUSIONS

LRH can be performed as safe and effective as ORH for HCC in regard to both surgical and oncological outcomes. LRH holds the benefit in less intraoperative blood loss and appears to achieve less postoperative morbidity, which could serve as a promising alternative to ORH in selected individuals.

Minimally invasive management of the entire treatment sequence in patients with stage IV colorectal cancer: a propensity-score weighting analysis

BACKGROUND

In patients with stage IV colorectal cancer (CRC), minimally invasive surgery (MIS) may offer optimal oncologic outcome with low morbidity. However, the relative benefit of MIS compared to open surgery in patients requiring multistage resections has not been evaluated.

METHODS

Patients who underwent totally minimally invasive (TMI) or totally open (TO) resections of CRC primary and liver metastases (CLM) in 2009-2016 were analyzed. Inverse probability of weighted adjustment by propensity score was performed before analyzing risk factors for complications and survival.

RESULTS

The study included 43 TMI and 121 TO patients. Before and after adjustment, TMI patients had significantly less cumulated postoperative complications (41% vs. 59%, p = 0.001), blood loss (median 100 vs. 200 ml, p = 0.001) and shorter length of hospital stay (median 4.5 vs. 6.0 days, p < 0.001). Multivariate analysis identified TO approach vs. MIS (OR = 2.4, p < 0.001), major liver resection (OR = 4.4, p < 0.001), and multiple CLM (OR = 2.3, p = 0.001) as independent risk factors for complications. 5-year overall survival was comparable (81% vs 68%, p = 0.59).

CONCLUSION

In patients with CRC undergoing multistage surgical treatment, MIS resection contributes to optimal perioperative outcomes without compromise in oncologic outcomes.

Stapleless laparoscopic left lateral sectionectomy for hepatocellular carcinoma: reappraisal of the Louisville statement by a young liver surgeon

BACKGROUND

Laparoscopic liver resection has been regarded as the standard treatment for liver tumors located at the left lateral liver sector. However, few studies have reported the results of laparoscopic left lateral sectionectomy (LLS) for HCC, not to mention the feasibility of this emerging technique for the less experienced liver surgeons. The current study would reappraise the Louisville statement by examining the outcome of LLS performed by a young liver surgeon.

METHODS

We retrospectively reviewed two separate groups of patients who underwent open or laparoscopic left lateral sectionectomies at Chung Gung Memorial Hospital, Linkou. All laparoscopic hepatectomies were performed by the index young surgeon following a stepwise stapleless LLS. The surgical results and oncological outcomes of laparoscopic vs. open hepatectomies (LH and OH, respectively) with the surgical indication of HCC at left lateral liver sector were further compared and analyzed.

RESULTS

18 of 29 patients in the laparoscopic group and 75 patients in the conventional open group had primary HCC. The demographic data was essentially the same for the two groups. Statistical analysis revealed that the LH group had smaller tumor size, higher blood transfusion requirement, longer duration of inflow control and parenchymal transection, and longer operation time. However, no significant difference was observed in terms of complication rate, mortality rate, and hospital stay between the two groups. After adjusting for tumor size, LH and OH showed no statistical difference in the amount of blood transfusion, operation time and patient survival.

CONCLUSIONS

This study demonstrated that stapleless LLS is a safe and feasible procedure for less experienced liver surgeons to resect HCC located at the left lateral liver sector. This stepwise stapleless LSS can not only achieve surgical results comparable to OH but also can provide a platform for liver surgeons to apply laparoscopic technique before conducting more complicated liver resections.

Changing trends and outcomes associated with the adoption of minimally invasive hepatectomy: a contemporary single-institution experience with 400 consecutive resections

BACKGROUND

Several studies published mainly from pioneers and early adopters have documented the evolution of minimally invasive hepatectomy (MIH). However, questions remain if these reported experiences are applicable and reproducible today. This study examines the changing trends, safety, and outcomes associated with the adoption of MIH based on a contemporary single-institution experience.

METHODS

This is a retrospective review of 400 consecutive patients who underwent MIH between 2006 and 2017 of which 360 cases (90%) were performed since 2012. To determine the evolution of MIH, the study population was stratified into four equal groups of 100 patients. Analyses were also performed of predictive factors and outcomes of open conversion.

RESULTS

Four hundred patients underwent MIH of which 379 (94.8%) were totally laparoscopic/robotic. Eighty-eight (22.0%) patients underwent major hepatectomy and 160 (40.0%) had resection of tumors located in the posterosuperior segments. There were 38 (9.5%) open conversions. Comparison across the four groups demonstrated that patients were older, had higher ASA score, and had increased frequency of previous abdominal surgery and repeat liver resections. There was also an increase in the proportion of patients who underwent totally laparoscopic/robotic surgery, major liver resection, resection of ≥ 3 segments, and multiple resections. Comparison of outcomes demonstrated that there was a significant decrease in open conversion rate, longer operation time, and increased use of Pringles maneuver. The presence of cirrhosis and institution experience (1st 100 cases) were independent predictors of open conversion. Patients who required open conversion had significantly increased operation time, blood loss, blood transfusion rate, morbidity, and mortality.

CONCLUSION

The case volume of MIH performed increased rapidly at our institution over time. Although the indications of MIH expanded to include higher risk patients and more complex hepatectomies, there was a decrease in open conversion rate and no change in other perioperative outcomes.

Pure laparoscopic right hemihepatectomy using the caudodorsal side approach (with videos)

BACKGROUND

In our process of standardizing laparoscopic right hemihepatectomy (Lap-RH), we found several advantages of the laparoscopic caudate lobe first approach by using a unique laparoscopic caudodorsal view.

METHODS

Between April 2012 and October 2017, 21 patients underwent pure Lap-RH at our hospital. The mean patient age was 62 years (range 36-75 years), and there were more male than female patients (66.7%). Of 21 patients, 11 had hepatocellular carcinoma, eight had metastatic tumor, and the other two had focal nodular hyperplasia and refractory liver abscess. All 21 patients had Child-Pugh class A liver function. The surgical technique was recorded on video.

RESULTS

The mean operative time was 409 min (range 241-522 min), and the mean blood loss was 279 g (range 0-1,010 g). No procedure was converted to open surgery. With regard to postoperative complications, one patient had bile leakage from the stump of the main Glissonean branch and another patient had abscess formation in the subphrenic space. No postoperative bleeding, hepatic failure, and mortality occurred.

CONCLUSIONS

Our standardized procedure of Lap-RH using the unique laparoscopic caudodorsal view is not only feasible but also confers a true advantage of the laparoscopic approach.

Surgical techniques and strategies for the treatment of primary liver tumours: hepatocellular and cholangiocellular carcinoma

Background

Owing to remarkable improvements of surgical techniques and associated specialities, liver surgery has become the standard of care for hepatocellular carcinoma and cholangiocarcinoma. Although applied with much greater safety, hepatic resections for primary liver tumours remain challenging and need to be integrated in a complex multidisciplinary treatment approach.

Methods

This literature review gives an update on the recent developments regarding basics of open and laparoscopic liver surgery and surgical strategies for primary liver tumours.

Results

Single-centre reports and multicentre registries mainly from Asia and Europe dominate the surgical literature on primary liver tumours, but the numbers of randomized trials are slowly increasing. Perioperative outcomes of open liver surgery for hepatocellular and cholangiocellular carcinoma have vastly improved over the last decades, accompanied by some progress in terms of oncological outcome. The laparoscopic approach is increasingly being applied in many centres, even for patients with underlying liver disease, and may result in decreased morbidity. Liver transplantation represents a cornerstone in the treatment of early hepatocellular carcinoma and is indispensable to achieve long-term survival. In contrast, resection remains the gold standard for cholangiocarcinoma in most countries, but interventional techniques are on the rise.

Conclusion

Liver surgery for primary tumours is complex, with a need for high expertise in a multidisciplinary team to achieve acceptable outcomes. Technical developments and clinical stratification tools have optimized individual care, but further improvements in oncological survival will likely require enhanced pre- and postoperative systemic and local treatment options.

Laparoscopic liver resection for colorectal liver metastasis patients allows patients to start adjuvant chemotherapy without delay: a propensity score analysis

BACKGROUND

Although adjuvant chemotherapy (AC) is widely used after liver resection (LR) for colorectal liver metastasis (CRLM), surgical invasiveness may lead to delay in starting AC, which is preferably started within 8 weeks postoperative. We investigated whether laparoscopic liver resection (LLR) for CRLM facilitates AC start without delay.

METHODS

Between November 2014 and December 2016, 117 consecutive CRLM patients underwent LR followed by AC. LLR and OLR were performed in 30 and 87 patients, respectively. After propensity score matching on clinical characteristics, oncologic features, and type of resection, the time interval between liver resection and AC start was compared between LLR (n = 22) and OLR (n = 44) groups.

RESULTS

After propensity score matching, major LR was performed in 8/22 (36%) and 15/44 (34%) cases of LLR and OLR groups, respectively (P = 1.0). Clinical-pathological characteristic and intraoperative findings were comparable between two groups. There was no significant difference in postoperative complications between the two groups. The time interval between liver resection and AC start was significantly shorter in LLR than in OLR group (43 ± 10 versus 55 ± 18 days, P = 0.012). While 15/44 (34%) patients started AC after 8 weeks postoperative in OLR group, all patients in LLR group started AC within 8 weeks.

CONCLUSIONS

LLR for CRLM is associated with quicker return to AC when compared to OLR. The delivery of AC without delay allows CRLM patients to optimize the oncologic treatment sequence.

Outcomes following laparoscopic versus open major hepatectomy: a meta-analysis

OBJECTIVE

The role of laparoscopic major hepatectomy (LMH) remains uncertain in current liver surgery. This meta-analysis aimed to compare surgical and oncological outcomes of LMH versus open major hepatectomy (OMH).

METHODS

A systematic search was conducted in PubMed, Embase, and the Cochrane Library database to identify all relevant publications. The statistical analysis was performed using Review Manager version 5.3. Continuous variables were calculated by standardized mean differences (SMD) with 95% confidence interval (CI), whereas dichotomous variables were calculated by odds ratio (OR) with 95%CI.

RESULTS

A total of 10 eligible studies with 1130 patients were identified, of which 455 (40.3%) patients in the LMH group and 675 (59.7%) patients in the OMH group. LMH was associated with less blood loss (SMD = -0.30, 95%CI: -0.43 to -0.18, p < .00001), less transfusion requirement (OR = 0.49, 95%CI: 0.29-0.82, p = .007), decreased postoperative morbidity (OR = 0.56, 95%CI: 0.42-0.76, p = .0001), and shorter hospital stay (SMD = -0.46, 95%CI: -0.69 to -0.24, p < .0001) when compared with the OMH group. But the operative time was significantly longer in LMH group (SMD = 0.61, 95%CI: 0.79-1.86, p = .01). Both the two groups achieved similar surgical margin and R0 resection rate for malignant lesions.

CONCLUSIONS

This meta-analysis demonstrated that LMH appeared to be feasible and safe in current liver surgery. LMH is associated with less blood loss, decreased postoperative morbidity, shorter hospital stay, and comparable oncological outcomes compared with OMH.

Predictors and implications of unplanned conversion during minimally invasive hepatectomy: an analysis of the ACS-NSQIP database

BACKGROUND

Minimally-invasive hepatectomy (MIH) is increasingly utilized; however, predictors and outcomes for patients requiring conversion to an open procedure have not been adequately studied.

METHODS

The 2014-15 ACS-NSQIP database was analyzed. Unplanned conversion was compared to successful MIH and elective open hepatectomy.

RESULTS

Among 6918 hepatectomies, 1062 (15.4%) underwent attempted MIH: 989 laparoscopic, 73 robotic. Conversion occurred in 203 (19.1%). Compared to successful MIH, patients requiring unplanned conversion experienced higher rates of complications (34.5% vs 14.6%, p<0.001), including bile leaks (7.4% vs 2.8%, p=0.002), organ space infection (6.4% vs 2.9%, p=0.016), UTI (4.9% vs 1.2%, p=0.002), perioperative bleeding (21.2% vs 6.1%, p<0.001), DVT (3.0% vs 0.8%, p=0.024), and sepsis (5.9% vs 1.9%, p=0.001). Conversion led to greater LOS (5 days vs 3 days, p<0.001) and 30-day mortality (3.0% vs 0.5%, p=0.005). Compared to elective open hepatectomy, conversion was associated with greater perioperative bleeding (21.2% vs 15.3%, p = 0.037). On multivariate analysis, major hepatectomy (OR 2.21, p<0.001), concurrent ablation (OR 1.79, p=0.020), and laparoscopic approach (vs. robotic) (OR 3.22, p=0.014) were associated with conversion.

CONCLUSION

Analysis of this national database revealed unplanned conversion during MIH is associated with greater morbidity and mortality. MIH should be approached cautiously in patients requiring major hepatectomy.

Critical appraisal of the impact of individual surgeon experience on the outcomes of laparoscopic liver resection in the modern era: collective experience of multiple surgeons at a single institution with 324 consecutive cases

BACKGROUND

Most studies analyzing the learning experience of laparoscopic liver resection (LLR) focused on the experience of one or two expert pioneering surgeons. This study aims to critically analyze the impact of individual surgeon experience on the outcomes of LLR based on the contemporary collective experiences of multiple surgeons at single institution.

METHODS

Retrospective review of 324 consecutive LLR from 2006 to 2016. The cases were performed by 10 surgeons over various time periods. Four surgeons had individual experience with <20 cases, four surgeons with 20-30 cases, and two surgeons with >90 cases. The cohort was divided into two groups: comparing a surgeon's experience between the first 20, 30, 40, and 50 cases with patients treated thereafter. Similarly, we performed subset analyses for anterolateral lesions, posterosuperior lesions, and major hepatectomies.

RESULTS

As individual surgeons gained increasing experience, this was significantly associated with older patients being operated, decreased hand-assistance, larger tumor size, increased liver resections, increased major resections, and increased resections of tumors located at the posterosuperior segments. This resulted in significantly longer operation time and increased use of Pringle maneuver but no difference in other outcomes. Analysis of LLR for tumors in the posterosuperior segments demonstrated that there was a significant decrease in conversion rates after a surgeon had experience with 20 LLR. For major hepatectomies, there was a significant decrease in morbidity, mortality, and length of stay after acquiring experience with 20 LLR.

CONCLUSION

LLR can be safely adopted today especially for lesions in the anterolateral segments. LLR for lesions in the difficult posterosuperior segments and major hepatectomies especially in cirrhosis should only be attempted by surgeons who have acquired a minimum experience with 20 LLR.