"Idealized" vs. "True" learning curves: the case of laparoscopic liver resection

The Learning Curve for Robotic Lateral Pelvic Lymph Node Dissection for Rectal Cancer: A View From the West

BACKGROUND

Lateral pelvic lymph node dissection is performed for selected patients with rectal cancer with persistent lateral nodal disease after neoadjuvant therapy. This technique has been slow to be adopted in the West because of concerns regarding technical difficulty. This is the first report on the learning curve for lateral pelvic lymph node dissection in the United States or Europe.

OBJECTIVE

This study aimed to analyze the learning curve associated with robotic lateral pelvic lymph node dissection.

DESIGN

Retrospective observational cohort.

SETTING

Tertiary academic cancer center.

PATIENTS

Consecutive patients from 2012 to 2021.

INTERVENTION

All patients underwent robotic lateral pelvic lymph node dissection.

MAIN OUTCOME MEASURES

The primary end points were the learning curves for the maximum number of nodes retrieved and urinary retention, which was evaluated with simple cumulative sum and 2-sided Bernoulli cumulative sum charts.

RESULTS

Fifty-four procedures were included. A single-surgeon learning curve (n = 35) and an institutional learning curve are presented in the analysis. In the single-surgeon learning curve, a turning point marking the end of a learning phase was detected at the 12th procedure for the number of retrieved nodes and at the 20th procedure for urinary retention. In the institutional learning curve analysis, 2 turning points were identified at the 13th procedure, indicating progressive improvements for the number of retrieved nodes, and at the 27th procedure for urinary retention. No sustained alarm signals were detected at any time point.

LIMITATIONS

The retrospective nature, small sample size, and the referral center nature of the reporting institution may limit generalizability.

CONCLUSIONS

In a setting of institutional experience with robotic colorectal surgery, including beyond total mesorectal excision resections, the learning curve for robotic lateral pelvic lymph node dissection is acceptably short. Our results demonstrate the feasibility of the acquisition of this technique in a controlled setting, with sufficient case volume and proctoring to optimize the learning curve. See Video Abstract.

LA CURVA DE APRENDIZAJE DE LA DISECCIN ROBTICA DE LOS GANGLIOS LINFTICOS PLVICOS LATERALES EN EL CNCER DE RECTO UNA VISIN DESDE OCCIDENTE

ANTECEDENTES:La disección lateral de los ganglios linfáticos pélvicos se realiza en pacientes seleccionados con cáncer de recto con enfermedad ganglionar lateral persistente tras el tratamiento neoadyuvante. La adopción de esta técnica en Occidente ha sido lenta debido a la preocupación por su dificultad técnica. Éste es el primer informe sobre la curva de aprendizaje de la disección de los ganglios linfáticos pélvicos laterales en EE.UU. o Europa.OBJETIVO:El objetivo de este estudio fue analizar la curva de aprendizaje asociada a la disección robótica de los ganglios linfáticos pélvicos laterales.DISEÑO:Cohorte observacional retrospectiva.LUGAR:Centro oncológico académico terciario.PACIENTES:Pacientes consecutivos desde 2012 al 2021.INTERVENCIÓN:Todos los pacientes fueron sometieron a disección robótica de ganglios linfáticos pélvicos laterales.PRINCIPALES MEDIDAS DE RESULTADO:Los criterios de valoración primarios fueron las curvas de aprendizaje tomando en cuenta el mayor número de ganglios recuperados y la retención urinaria que fueron evaluados con gráficos de suma acumulativa simple y de suma acumulativa de Bernoulli de dos caras.RESULTADOS:Fueron incluidos 54 procedimientos. En el análisis se presentan una curva de aprendizaje de un solo cirujano (n = 35) y una curva de aprendizaje institucional. En la curva de aprendizaje de un solo cirujano, se detectó un punto de inflexión que marcaba el final de una fase de aprendizaje en el duodécimo procedimiento para el número de ganglios extraídos y en el vigésimo para la retención urinaria. En el análisis de la curva de aprendizaje institucional, se identificaron dos puntos de inflexión en las intervenciones 13.ª y 26.ª, que indicaron mejoras progresivas en el número de ganglios extraídos, y en la 27.ª en la retención urinaria. No se detectaron señales de alarma sostenidas en ningún momento.LIMITACIONES:La naturaleza retrospectiva, el pequeño tamaño de la muestra y la naturaleza de centro de referencia de la institución informante que pueden limitar la capacidad de generalizarse.CONCLUSIONES:En un entorno de experiencia institucional con cirugía robótica colorrectal incluyendo más allá de las resecciones TME, la curva de aprendizaje para la disección robótica de ganglios linfáticos pélvicos laterales es aceptablemente corta. Nuestros resultados demuestran la viabilidad de la adquisición de esta técnica en un entorno controlado, con un volumen de casos suficiente y una supervisión que puede optimizar la curva de aprendizaje. (Traducción-Dr. Osvaldo Gauto ).

Perioperative Outcomes of Laparoscopic Liver Resection and Risk Factors for Adverse Events

PURPOSE

The perioperative outcomes and risk factors associated with adverse events (AEs) after initial laparoscopic liver resection (LLR) are unclear. We studied the outcomes of LLR and identified the predictive factors for AEs.

MATERIALS AND METHODS

Data from 100 adults who underwent LLR between April 2014 and February 2020 were reviewed. Baseline characteristics, surgery details, intraoperative data, and postoperative outcomes were tabulated. The AEs included conversion to open surgery, morbidity, and mortality.

RESULTS

Major and minor LLRs accounted for 16% and 84% of cases, respectively. Of the indications for LLR, 88% were malignancies. Conversion to open surgery was necessary for 7% of the patients, the overall morbidity rate was 21%, the major morbidity rate was 7%, and the 90-day mortality rate was 1%. Although the incidence of AEs was higher after major LLR (37.5%) than after minor LLR (21.4%), the difference was not statistically significant (P=0.095); the rate of AEs in the resection of posterosuperior segments (43.7%) did not significantly differ from that of the anteroinferior segments (19.2%; P=0.095). Multivariable analysis revealed that the significant predictors of AEs included American Society of Anesthesiologists (ASA) class III (odds ratio, 5.76; 95% confidence interval, 1.74-19.1; P=0.003) and an operative time longer than 5 hours (odds ratio, 9.20; 95% confidence interval, 2.41-35.07; P<0.001).

CONCLUSION

To improve outcomes in LLR, patients with ASA class III and those in whom surgery is expected to last longer than 5 hours should be taken into account for better patient selection.

External validation of different difficulty scoring systems of laparoscopic liver resection for hepatocellular carcinoma

BACKGROUND

Several difficulty scoring systems (DSSs) have been proposed for evaluating difficulty of laparoscopic liver resection (LLR) and no study has validated their performance in a hepatocellular carcinoma (HCC)-only cohort at the same time.

METHODS

All cases with HCC that underwent LLR from January 2015 to December 2020 in our center were retrospectively collected. Performance of the IWATE-DSS, Halls-DSS, Hasegawa-DSS, and Kawaguchi-DSS in predicting perioperative outcomes was evaluated. Subgroup analyses were conducted to compare perioperative outcomes between surgeons on the learning curve and surgeons that have gone through the learning curve.

RESULTS

For all four DSSs, there were significant distributions of applying bleeding control, surgical time, estimated blood loss, postoperative major complications, and postoperative hospital stay among different groups of each DSS (P all < 0.05). Conversion to laparotomy or not was significantly distributed in different groups of the IWATE-DSS (P = 0.006) and Halls-DSS (P = 0.022), while it was not in the Hasegawa-DSS (P = 0.056) and Kawaguchi-DSS (P = 0.183). Trend tests showed that the conversion rates increased with higher DSS points in the IWATE-DSS (P < 0.001) and the Kawaguchi-DSS (P = 0.021), while not in the Halls-DSS (P = 0.064) and the Hasegawa-DSS (P = 0.068). In the medium and advanced/expert difficulty-level subgroups defined by the IWATE-DSS, there were larger estimated blood loss (P in medium-difficulty group = 0.009; P in the advanced/expert difficulty group = 0.004) and longer postoperative hospital stay (P in the medium-difficulty group = 0.012; P in the advanced/expert group = 0.035) in the learner-performed cases.

CONCLUSIONS

All DSSs performed well in predicting applying bleeding control, surgical time, estimated blood loss, postoperative major complications, and postoperative hospital stay, while only the IWATE-DSS was able to predict whether conversion to laparotomy or not for HCC patients underwent LLR. The IWATE-DSS was also able to help surgeons on the LLR learning curve choose cases and guide clinical practices.

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).

Hepatectomy for Solitary Hepatocellular Carcinoma: Resection Margin Width Does Not Predict Survival

BACKGROUND

The survival benefit of negative margins for hepatocellular carcinoma (HCC) has been demonstrated. However, there is no consensus regarding the optimal resection margin width. We assessed the impact of hepatic resection margin width for solitary HCC on overall (OS), recurrence-free (RFS), and liver-specific recurrence-free survival (LSRFS).

METHODS

Clinicopathologic data were retrospectively collected for solitary HCC patients who underwent a negative margin hepatectomy (1992-2015). Margin width was categorized in tertiles as "narrow" (≤ 0.3 cm), "intermediate" (0.31-1.0 cm), or "wide" (> 1.0 cm). Survival was compared among groups.

RESULTS

Of the 178 included patients, most were male (76%); median age, MELD score, and tumor size were 63 years, 8, and 5.2 cm, respectively; 93% were Child-Pugh class A. Median margin width was 0.5 cm. Median follow-up and OS were 47.8 months and 76.7 months, respectively. There was no significant survival difference among narrow, intermediate, and wide margin groups with a median OS of 53 months (IQR 21-not reached [NR]), 74 months (IQR 14-138), and 97 months (IQR 37-142) (p = 0.87), respectively. Median RFS was 33.0 months; again, there was no difference among narrow, intermediate, and wide margin groups with a median of 31 months (IQR 18-NR), 45 months (IQR 14-NR), and 27 months (IQR 11-NR), respectively (p = 0.66). Median LSRFS was 63.0 months (IQR 14-NR) with no difference among groups (p = 0.87). In multivariate analyses, margin width was not associated with OS (p = 0.77), RFS (p = 0.74), or LSRFS (p = 0.92). Findings were similar in all subgroups analyzed (≤ 5 cm, > 5 cm, microvascular invasion, T1, T2/T3, anatomical or non-anatomical resection, major or minor hepatectomy).

CONCLUSIONS

Narrow margins appear to be oncologically safe and the feasibility of achieving wide margins should not determine resectability.

Development of a novel educational tool to assess skills in laparoscopic liver surgery using the Delphi methodology: the laparoscopic liver skills scale (LLSS)

BACKGROUND

No specific performance assessment scales have been reported in laparoscopic liver resection. This study aimed at developing an objective scale specific for the assessment of technical skills for wedge resection in anterior segments (WRAS) and left lateral sectionectomy (LLS).

METHODS

A laparoscopic liver skills scale (LLSS) was developed using a hierarchical task analysis. A Delphi method obtained consensus among five international experts on relevant steps that should be included into the LLSS for assessment of operative performances. The consensus was predefined using Cronbach's alpha > 0.80.

RESULTS

A semi-structured review extracted 15 essential subtasks for full laparoscopic WRAS and LLS for evaluation in the Delphi survey. Two rounds of the survey were conducted. Three over 15 subtasks did not reach the predefined level of consensus. Based on the expert's comments, 13 subtasks were reformulated, 4 subtasks were added, and a revised skills scale was developed. After the 2nd round survey (Cronbach's alpha 0.84), 19 subtasks were adopted. The LLSS was composed of three main parts: patient positioning and intraoperative preparation (task 1 to 8), the core part of the WRAS and LLS procedure (tasks 9 to 14), and completion of procedure (task 15 to 19).

CONCLUSIONS

The LLSS was developed for measuring the skill set for the education of safe and secure laparoscopic WRAS and LLS procedures in a dedicated training program. After validation, this scale could be also used as an assessment tool in the operating room and extrapolated as an operative roadmap to other complex procedures.

Laparoscopic versus open hepatectomy for intrahepatic cholangiocarcinoma: An individual patient data survival meta-analysis

BACKGROUND

We compared the outcomes of laparoscopic hepatectomy (LH) vs. open hepatectomy (OH) for intrahepatic cholangiocarcinoma (iCCA).

METHODS

A systematic review of the MEDLINE, EMBASE, Scopus, and Cochrane Library databases was performed using PRISMA guidelines (end-of-search date: 08-June-2020). Individual patient data on overall survival (OS) and recurrence-free survival (RFS) were extracted. Random-effects meta-analyses, and one- and two-stage survival analyses were conducted.

RESULTS

Eight retrospective cohort studies comparing LH (n = 544) vs. OH (n = 2256) were identified. LH demonstrated lower overall complication (Risk ratio [RR] = 0.64, 95% confidence interval [CI]: 0.46-0.90; p = 0.01), surgical lymphadenectomy (RR = 0.74, 95% CI: 0.58-0.93; p = 0.01) and margin-positive resection (RR = 0.78, 95% CI: 0.62-0.99; p = 0.04) rates, and higher recurrence-free rate (RR = 1.24, 95% CI: 1.01-1.51; p = 0.04) vs. OH. In Cox regression, no difference was observed regarding OS (Hazard Ratio [HR] = 1.11, 95% CI: 0.65-1.91; p = 0.70) and RFS (HR = 1.19, 95% CI: 0.74-1.90; p = 0.47).

CONCLUSION

The use of LH should be considered when feasible in well-selected iCCA patients by hepatobiliary surgeons with experience in minimally-invasive surgery.

Economic analysis of open versus laparoscopic versus robotic hepatectomy: a systematic review and meta-analysis

BACKGROUND

Following the publication of reports from landmark international consensuses (Louisville 2008 and Morioka 2014), minimally invasive hepatectomy became widely accepted as a legitimate alternative to open surgery. We aimed to compare the operative, hospitalization, and total economic costs of open (OLR) vs. laparoscopic (LLR) vs. robotic liver resection (RLR).

METHODS

We performed a systematic literature review (end-of-search date: July 3, 2020) according to the PRISMA statement. Random-effects meta-analyses were conducted. Quality assessment was performed with the Cochrane Risk of Bias tool for randomized controlled trials, and the Newcastle-Ottawa Scale for non-randomized studies.

RESULTS

Thirty-eight studies reporting on 3847 patients (1783 OLR; 1674 LLR; 390 RLR) were included. The operative costs of LLR were significantly higher than those of OLR, while subgroup analysis also showed higher operative costs in the LLR group for major hepatectomy, but no statistically significant difference for minor hepatectomy. Hospitalization costs were significantly lower in the LLR group, with subgroup analyses indicating lower costs for LLR in both major and minor hepatectomy series. No statistically significant difference was observed regarding total costs between LLR and OLR both overall and on subgroup analyses in either major or minor hepatectomy series. Meta-analyses showed higher operative, hospitalization, and total costs for RLR vs. LLR, but no statistically significant difference regarding total costs for RLR vs. OLR.

CONCLUSION

LLR's higher operative costs are offset by lower hospitalization costs compared to OLR leading to no statistically significant difference in total costs, while RLR appears to be a more expensive alternative approach.

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.

When should we choose a laparoscopic approach? A high-volume center recommendation score

Laparoscopic liver resection is a demanding procedure that is undergoing continuous development. The surgeon's skill is constantly improving, new surgical instruments are being introduced, and the indications for this procedure are expanding. However, there is still great concern about patient safety during the procedure and it is not commonly performed in many centers, although numerous studies have confirmed the safety and feasibility of laparoscopic liver techniques. Our center tries to use laparoscopy routinely for most cases and we do not consider conversion to open surgery to be a complication. We present our current opinion on patient selection for laparoscopic liver resection in the hope of encouraging more centers to adopt and develop this technique. Although laparoscopic liver resection is not an official standard of care, it should be considered according to the surgeon's experience and available resources.

The external validation of a difficulty scoring system for predicting the risk of intraoperative complications during laparoscopic liver resection

BACKGROUND

This study aimed to externally validate and upgrade the recent difficulty scoring system (DSS) proposed by Halls et al. to predict intraoperative complications (IOC) during laparoscopic liver resection (LLR).

METHODS

The DSS was validated in a cohort of 128 consecutive patients undergoing pure LLRs between 2008 and 2019 at a single tertiary referral center. The validated DSS includes four difficulty levels based on five risk factors (neoadjuvant chemotherapy, previous open liver resection, lesion type, lesion size and classification of resection). As established by the validated DSS, IOC was defined as excessive blood loss (> 775 mL), conversion to an open approach and unintentional damage to surrounding structures. Additionally, intra- and postoperative outcomes were compared according to the difficulty levels with usual statistic methods. The same five risk factors were used for validation done by linear and advanced nonlinear (artificial neural network) models. The study was supported by mathematical computations to obtain a mean risk curve predicting the probability of IOC for every difficulty score.

RESULTS

The difficulty level of LLR was rated as low, moderate, high and extremely high in 36 (28.1%), 63 (49.2%), 27 (21.1%) and 2 (1.6%) patients, respectively. IOC was present in 23 (17.9%) patients. Blood loss of >775 mL occurred in 8 (6.2%) patients. Conversion to open approach was required in 18 (14.0%) patients. No patients suffered from unintentional damage to surrounding structures. Rates of IOC (0, 9.5, 55.5 and 100%) increased gradually with statistically significant value among difficulty levels (P < 0.001). The relations between the difficulty level, need for transfusion, operative time, hepatic pedicle clamping, and major postoperative morbidity were statistically significant (P < 0.05). Linear and nonlinear validation models showed a strong correlation (correlation coefficients 0.914 and 0.948, respectively) with the validated DSS. The Weibull cumulative distribution function was used for predicting the mean risk probability curve of IOC.

CONCLUSION

This external validation proved this DSS based on patient's, tumor and surgical factors enables us to estimate the risk of intra- and postoperative complications. A surgeon should be aware of an increased risk of complications before starting with more complex procedures.

Modified liver hanging maneuver in laparoscopic major hepatectomy: the learning curve and evolution of indications

BACKGROUND

Laparoscopic major hepatectomy is a technically challenging procedure requiring a steep learning curve. The liver hanging maneuver is a useful technique in liver resection, especially for large or invasive tumors, a relative contraindication of the laparoscopic approach. Therefore, this study aimed to evaluate the learning curve for laparoscopic major hepatectomy using the liver hanging maneuver and extended indications.

METHODS

Patients who underwent laparoscopic major hepatectomy using the liver hanging maneuver by a single surgeon from January 2013 and September 2018 were retrospectively reviewed. Our hanging technique involves placing the hanging tape along the inferior vena cava for right-sided hepatectomy or the ligamentum venosum for left-sided hepatectomy. The upper end of the tape was placed at the lateral side of the major hepatic veins. The learning curve for operating time and blood loss was evaluated using the cumulative sum (CUSUM) method.

RESULTS

Among 53 patients, 18 underwent right hepatectomy, 26 underwent left hepatectomy, and 9 underwent right posterior sectionectomy. CUSUM analysis showed that operative time and blood loss improved after the 30th laparoscopic major hepatectomy. The 53 consecutive patients were divided into two groups (early, patients 1-30; late, patients 31-53). The median operative time was lower in the late group, but the difference was not statistically significant (270 vs. 245 min, p = 0.261). The median blood loss was also significantly lower in the late group (350 vs. 150 ml, p < 0.001). Large tumors (measuring > 10 cm) and tumors in proximity to major vessels were significantly higher in the late group (0 vs. 17.4%, p = 0.018; 3.3 vs. 21.7%, p = 0.036; respectively).

CONCLUSION

This study shows that laparoscopic major hepatectomy using the modified liver hanging maneuver has a learning curve of 30 cases. After procedure standardization, the indications have gradually been extended to large or invasive tumors.

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.

Multicentre analysis of the learning curve for laparoscopic liver resection of the posterosuperior segments

BACKGROUND

Laparoscopic liver resection demands expertise and a long learning curve. Resection of the posterosuperior segments is challenging, and there are no data on the learning curve. The aim of this study was to evaluate the learning curve for laparoscopic resection of the posterosuperior segments.

METHODS

A cumulative sum (CUSUM) analysis of the difficulty score for resection was undertaken using patient data from four specialized centres. Risk-adjusted CUSUM analysis of duration of operation, blood loss and conversions was performed, adjusting for the difficulty score of the procedures. A receiver operating characteristic (ROC) curve was used to identify the completion of the learning curve.

RESULTS

According to the CUSUM analysis of 464 patients, the learning curve showed an initial decrease in the difficulty score followed by an increase and, finally, stabilization. More patients with cirrhosis or previous surgery were operated in the latest phase of the learning curve. A smaller number of wedge resections and a larger number of anatomical resections were performed progressively. Dissection using a Cavitron ultrasonic surgical aspirator and the Pringle manoeuvre were used more frequently with time. Risk-adjusted CUSUM analysis showed a progressive decrease in operating time. Blood loss initially increased slightly, then stabilized and finally decreased over time. A similar trend was found for conversions. The learning curve was estimated to be 40 procedures for wedge and 65 for anatomical resections.

CONCLUSION

The learning curve for laparoscopic liver resection of the posterosuperior segments consists of a stepwise process, during which accurate patient selection is key.

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.

[Early outcomes of robot-assisted liver resection]

AIM

To assess an experience of robot-assisted liver resection using CUSUM-test.

MATERIAL AND METHODS

The results of 46 robot-assisted liver resections were retrospectively analyzed by using of CUSUM-test.

RESULTS

There were 3 periods in development of the technology. The 1^st period - procedures with the lowest index of difficulty (n=16), the 2^nd period - expansion of the indications for difficult resections (n=18) and the 3^rd period - stabilization of the results (n=12). The dynamics of difficulty index, intraoperative blood loss, duration of procedure and morbidity (Clavien-Dindo Grade II-V) were evaluated. Five liver resections were needed to decrease blood loss and duration of the procedure. Expansion of indications was feasible after 16 procedures. Stable results were obtained after 34 liver resections.

Advances and challenges in laparoscopic surgery in the management of hepatocellular carcinoma

Hepatocellular carcinoma is the fifth most common malignancy and the third most common cause of cancer-related mortality worldwide. From the wide variety of treatment options, surgical resection and liver transplantation are the only therapeutic ones. However, due to shortage of liver grafts, surgical resection is the most common therapeutic modality implemented. Owing to rapid technological development, minimally invasive approaches have been incorporated in liver surgery. Liver laparoscopic resection has been evaluated in comparison to the open technique and has been shown to be superior because of the reported decrease in surgical incision length and trauma, blood loss, operating theatre time, postsurgical pain and complications, R0 resection, length of stay, time to recovery and oral intake. It has been reported that laparoscopic excision is a safe and feasible approach with near zero mortality and oncologic outcomes similar to open resection. Nevertheless, current indications include solid tumors in the periphery < 5 cm, especially in segments II through VI, while according to the consensus laparoscopic major hepatectomy should only be performed by surgeons with high expertise in laparoscopic and hepatobiliary surgery in tertiary centers. It is necessary for a surgeon to surpass the 60-cases learning curve observed in order to accomplish the desirable outcomes and preserve patient safety. In this review, our aim is to thoroughly describe the general principles and current status of laparoscopic liver resection for hepatocellular carcinoma, as well as future prospects.

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.

Comparative analysis of learning curve in complex robot-assisted and laparoscopic liver resection

BACKGROUND

There is no comparative analysis of the learning curves for robot-assisted and laparoscopic liver resection. We aimed to compare learning curves in complex robotic and conventional laparoscopic liver resections with regards to estimation of the difficulty index score.

METHODS

The results of 131 consecutive liver resections were analyzed retrospectively (40 robot-assisted and 91 laparoscopic). The learning curve evaluation was based on calculation of procedures number before significant change of the difficulty index for minimally invasive liver resection or the rate of posterosuperior segments resection. Groups of early and late experience were compared in every type of approach (robot-assisted and laparoscopic).

RESULTS

Significant increase of difficulty index (from 5.0 [3.0-7.7] to 7.3 [4.3-10.2]) of robotic procedures required 16 procedures. It was necessary to perform 29 laparoscopic resections in order to significantly increase the rate of laparoscopic posterosuperior segments resection but without significant increase of difficulty index. The implementation of minimally invasive liver resection started with the robotic approach.

CONCLUSION

The learning curve for robot-assisted liver resections is shorter in comparison with laparoscopic resections. The inclusion of robot-assisted resections in a minimally invasive liver surgery program may be useful to rapidly increase the complexity of laparoscopic liver resections.

Trends in indications, complications and outcomes for venous resection during pancreatoduodenectomy

Background

Pancreatoduodenectomy with superior mesenteric–portal vein resection has become a common procedure in pancreatic surgery. The aim of this study was to compare standard pancreatoduodenectomy with pancreatoduodenectomy plus venous resection at a high-volume centre, and to examine trends in management and outcome over a decade for the latter procedure.

Methods

This retrospective observational study included all patients undergoing pancreatoduodenectomy with or without venous resection at Oslo University Hospital between January 2006 and December 2015. Trends were evaluated by assessing preoperative clinical and radiological characteristics, as well as perioperative outcomes in three time intervals (early, intermediate and late).

Results

A total of 784 patients had a pancreatoduodenectomy, of whom 127 (16·2 per cent) underwent venous resection. Venous resection resulted in a longer operating time (median 422 versus 312 min; P = 0·001) and greater estimated blood loss (EBL) (median 700 versus 500 ml; P = 0·004) than standard pancreatoduodenectomy. The rate of severe complications was significantly higher for pancreatoduodenectomy with venous resection (37·0 versus 26·3 per cent; P = 0·014). The overall burden of complications, evaluated using the Comprehensive Complication Index (CCI), did not differ (median score 8·7 versus 8·7; P = 0·175). Trends in venous resection over time showed a significant reduction in EBL (median 1050 versus 375 ml; P = 0·001) and duration of hospital stay (median 14 versus 9 days; P = 0·011) between the early and late periods. However, despite an improvement in the intermediate period, severe complication rates returned to baseline in the late period (18 of 43 versus 9 of 42 versus 20 of 42 patients in early, intermediate and late periods respectively; P = 0·032), as did CCI scores (median 20·9 versus 0 versus 20·9; P = 0·041).

Conclusion

Despite an initial improvement in severe complications for venous resection during pancreatoduodenectomy, this was not maintained over time. Every fourth patient with venous resection needed relaparotomy, most frequently for bleeding.

Mastery learning: how is it helpful? An analytical review

The desire to be good at one's work grows out of the aspiration, competition, and a yearning to be the best. Surgeons, in their aim to provide the best care possible to their patients, adopt this behavior to achieve high levels of expert performance through mastery learning, and the surgical training attempts to prepare them optimally to lead a virtuous and productive life. The proponents of the framework reject evidence that suggests that other variables are also necessary to achieve high levels of expert performance. Here, we review various models and designs to achieve mastery along with their pros and cons to help us understand how mastery learning is helpful in surgical practice.