Defining Surgical Difficulty According to the Perceived Complexity of Liver Resection: Validation of a Complexity Classification in Patients with Hepatocellular Carcinoma

Navigating Complexity in Liver Resection: A Narrative Review of Factors Influencing Intraoperative Difficulty

Background: Liver resection remains the cornerstone for curative management in primary liver malignancies. Liver surgery ranges from simple wedge resections to complex hepatectomies involving vascular or biliary reconstructions. The anatomical complexity of the liver and these varied surgical approaches create challenges in assessing operative difficulty. This literature review explores the key factors influencing operative difficulty in liver resection for primary liver malignancy across surgical techniques. Methods: A broad literature review was conducted to determine the factors that were associated with increased operative difficulty in liver resection using the Embase, PubMed, and Cochrane databases for studies published between 2000 and 2025. Results: This review identifies several patient, tumor, and surgical factors that influence operative difficulty in liver resection. Numerous difficult scoring systems were identified, yet their applicability across different operative approaches remains uncertain. Across open and minimally invasive techniques, tumor size and location are commonly used to determine complexity. However, debate remains regarding the optimal cutoff for tumor diameter. Other identified factors include the extent of resection, patient-specific variables (e.g., cirrhosis, body mass index, previous surgeries), and surgical technique. In addition, liver resection procedures classified based on the 2000 Brisbane terminology have been stratified into three groups of increasing difficulty. Conclusion: The ability to predict operative difficulty is useful for case selection, surgical planning, and risk stratification for meaningful shared decision-making. Future research should focus on refining predictive models by integrating composite measures, including patient-reported outcomes and long-term survival. A unified, validated scoring system applicable across surgical techniques could enhance consistency in clinical practice and research to improve outcomes.

Patients' Surgical History Profile and Its Association With Complexity in Major Emergency Abdominal Surgery

INTRODUCTION

Emergency abdominal surgery often involves patients with a surgical history. Previous abdominal surgery can complicate new procedures. The correlation between surgical history and complexity in major emergency surgery has not been assessed. The purpose of this study was to profile patients undergoing emergency abdominal surgery, regarding quantity and type of previous abdominal procedures and to assess their association with intraoperative complexity. We hypothesized that a history of abdominal surgery would be associated with increased intraoperative complexity, defined as a composite outcome of complicating factors and intraoperative events.

MATERIALS AND METHODS

We conducted an exploratory analysis of 754 consecutive patients undergoing major emergency abdominal surgery at a single institution. While multiple procedure- and patient-related variables were prospectively recorded in our local database, data on patient history and previous abdominal surgeries were collected retrospectively. Intraoperative iatrogenic lesions (unintended lesions to intra-abdominal organs), prolonged procedural time (≥3 h), or excessive intraoperative bleeding (≥1 L) were established as indicative of a complex procedure ('complexity factor'). Data were analyzed using multivariable logistic regression to identify significant preoperative risk factors for intraoperative complexity.

RESULTS

A total of 754 patients were included, with a median age of 71 y (interquartile range: 58-79), and 51% of the cohort were female. Among them, 476 patients (61%) had a history of previous abdominal surgery. In 192 (25%) of the procedures, surgeons reported at least one complexity factor. Previous colonic or rectal resection was associated with intraoperative complexity (2.34 risk ratio, confidence interval 95: 1.01-5.41, P = 0.05). Other significant factors were prior laparotomy, severe intra-abdominal adhesions, previous intra-abdominal abscess, and prior small bowel obstruction.

CONCLUSIONS

This study profiles emergency surgical patients with a history of abdominal surgery and explores the associations between previous surgery and complexity in subsequent procedures. Awareness of factors associated with increased procedural complexity is valuable to the surgical and anesthesiologic team in the planning of the procedure.

Defining Surgical Difficulty During Open Right Lobe Donor Hepatectomy and its Prediction Using Preoperative Donor Computed Tomography Morphometry

Background

There is no accepted way to define difficult donor hepatectomy (DiffDH) during open right live donor hepatectomy (ORLDH). There are also no studies exploring association between DiffDH and early donor outcomes or reliable pre-operative predictors of DiffDH.

Methods

Consecutive ORLDH performed over 18 months at a single center were included. Intraoperative parameters were used to develop an objective definition of DiffDH. The impact of DiffDH on early postoperative outcomes and achievement of textbook outcome (TO) was evaluated. Donor morphometry data on axial and coronal sections of donor computed tomography (CT) at the level of portal bifurcation were collected. Donor and graft factors predictive of DiffDH were evaluated using univariate and multivariate logistic regression.

Results

One-hundred-eleven donors (male: 40.5%, age: 34 ± 9.5 years) underwent ORLDH during the study period. The difficulty score was constructed using five intraoperative parameters, i.e., operating time, transection time, estimated blood loss, need for intraoperative vasopressors, and need for Pringle maneuver. Donors were classified as DiffDH (score ≥ 2) or standard donor hepatectomy (StDH) (score <2). Twenty-nine donors (26%) were classified as DiffDH. DiffDH donors suffered greater all-cause morbidity (P = 0.004) but not major morbidity (Clavien-Dindo score >2; P = 0.651), more perioperative transfusion (P = 0.013), increased postoperative systemic inflammatory response syndrome (P = 0.034), delay in achieving full oral diet (P = 0.047), and a 70% reduced chance of achieving TO as compared to StDH (P = 0.007). On logistic regression analysis, increasing right lobe anteroposterior depth (RLdepth) was identified as an independent predictor of DiffDH (Odds ratio: 2.0 (95% confidence interval = 1.2, 3.3), P < 0.006). Receiver operating characteristic curve analysis identified an RLdepth of >14 cm as the best predictor of DiffDH (sensitivity:79%, specificity: 66%, area under curve = 0.803, P < 0.001).

Conclusion

We report a novel definition of DiffDH and show that it is associated with worse postoperative outcomes, including a lesser chance of achieving TO. We also report that DiffDH can be predicted from readily available donor CT parameters.

Development of a novel difficulty scoring system for laparoscopic liver resection procedure in patients with intrahepatic duct stones

BACKGROUND

For intrahepatic duct (IHD) stones, laparoscopic liver resection (LLR) is currently a reliable treatment. However, the current LLR difficulty scoring system (DSS) is only available for patients with hepatocellular carcinoma.

AIM

To explore the development of a DSS for IHD stone patients with LLR and the validation of its reliability.

METHODS

We used clinical data from 80 patients who received LLR for IHD stones. Forty-six of these patients were used in multiple linear regression to construct a scoring system. Another 34 patients from different centers were used as external validation. The completeness of our DSS was then evaluated in patients with varying degrees of surgical difficulty based on documented surgical outcomes in the study group of patients.

RESULTS

The following five predictors were ultimately included and scored by calculating the weighted contribution of each factor to the prediction of operative time in the training cohort: Location of stones, number of stones ≥ 3, stones located in the bile ducts of several grades, previous biliary surgery less than twice, distal bile duct atrophy. Subsequently, the data set was validated using a DSS developed from the variables. The following variables were identified as statistically significant in external validation: Operative time, blood loss, intraoperative transfusion, postoperative alanine aminotransferase, and Clavien-Dindo grading ≥ 3. These variables demonstrated statistically significant differences in patients with three or more grades.

CONCLUSION

Patients with IHD stones have varying degrees of surgical difficulty, and the newly developed DSS can be validated with external data to effectively predict risks and complications after LLR surgery.

Highly complex liver resections: Exploring the boundaries of feasibility and safety

INTRODUCTION

In select clinical scenarios, advanced techniques for volume manipulation and vascular reconstruction are needed for complete hepatic tumor removal. These highly complex liver resections (HCLRs) entail a heightened risk of severe complications. Here, we describe the results of HCLR performed in a 3-year time period.

MATERIALS AND METHODS

We conducted a retrospective analysis encompassing patients who underwent hepatic resections between June 15, 2020, and June 15, 2023. HCLR was defined according to previously established criteria, and included associating liver partition and portal vein ligation for staged hepatectomy. The outcomes of HCLR were compared to all non-HCLR performed within the same time frame.

RESULTS

Among 167 hepatic resections, 26 were considered HCLR, and all were major resections. Five utilized total vascular exclusion, with venovenous bypass in three, and hypothermic liver perfusion in three. Five resections included vascular reconstructions, and one included hypothermic circulatory arrest for extraction of a tumor extending to the right atrium. Of the non-HCLR, 38 (26.9%) were major, and 49 (34.7%) were performed laparoscopically. The rates of overall major postoperative complications were comparable between those who underwent HCLR versus non-HCLR. HCLR was associated with increased rates of biliary complications, readmissions, and reoperation. However, no postoperative 90-day mortality was documented within patients that underwent HCLR compared to two in the non-HCLR group.

CONCLUSIONS

In expert hands, HCLR can be performed with acceptable complication profile, akin to that of major non-HCLR. Those with questionable resectability should be referred to tertiary hepato-pancreato-biliary centers.

Does CPT Modifier 22 Appropriately Reflect a Difficult Pancreaticoduodenectomy? Retrospective Analysis of Operative Outcomes and Cost

BACKGROUND

CPT coding allows addition of a 2-digit modifier code to denote particularly difficult procedures necessitating additional reimbursement, called the modifier 22. The use of modifier 22 in relation to pancreatic surgery and outcomes, specifically pancreaticoduodenectomy (PD), has not been explored.

STUDY DESIGN

All PDs performed from 2010 to 2019 at a quaternary healthcare system were analyzed for differences in preoperative characteristics, outcomes, and cost based on the use of modifier 22. Adjusted logistic regression analysis was used to identify factors predictive of modifier 22 use.

RESULTS

A total of 1,284 patients underwent PD between 2010 and 2019; 1,173 with complete data were included, of which 320 (27.3%) were coded with modifier 22. Patients coded with modifier 22 demonstrated a significantly longer duration of surgery (365.9 ± 168.4 vs 227 ± 97.1; p < 0.001). They also incurred significantly higher cost of index admission ($37,446 ± 34,187 vs $28,279 ± 27,980; p = 0.002). An adjusted multivariable analysis (specifically adjusted for surgeon variation) revealed duration of surgery (p < 0.001), neoadjuvant chemotherapy (p = 0.039), class II obesity (p = 0.019), and chronic pancreatitis (p = 0.005) to be predictive of modifier 22 use.

CONCLUSIONS

Despite the subjective nature of this CPT modifier, modifier 22 is an appropriate marker of intraoperative difficulty. Preoperative and intraoperative characteristics that lead to its addition may be used to further delineate difficult PDs.

Delimiting Low Level of Difficulty Scoring System Based on the Extent of Resection Difficulty Scoring System for Laparoscopic Liver Resection

Background: The difficulty scoring system based on the extent of resection (DSS-ER) is a common tool for assessing the difficulty and risk of laparoscopic liver resection (LLR), but DSS-ER fails to comprehensively and accurately assess low level for beginners. Methods: The 93 cases of LLRs for primary liver cancer in the general surgery department of the Second Affiliated Hospital of Guangxi Medical University from 2017 to 2021 were retrospectively analyzed. The low level of DSS-ER difficulty scoring system was reclassified into three grades. The intraoperative and postoperative complications were compared among different groups. Results: There were significant differences in the operative time, blood loss, intraoperative allogeneic blood transfusion, conversion to laparotomy, and allogeneic blood transfusion among the different groups. Meanwhile, the postoperative complications were mainly pleural effusion and pneumonia, and the incidence of grade III was higher compared with other two grades. No significant difference existed in the postoperative biliary leakage and liver failure among three grades. Conclusions: This reclassified low level of DSS-ER difficulty scoring system has certain clinical value for LLR beginners to complete the corresponding learning curve.

Development and Validation of a Difficulty Scoring System for Laparoscopic Liver Resection to Treat Hepatolithiasis

Background and Objectives: A difficulty scoring system was previously developed to assess the difficulty of laparoscopic liver resection (LLR) for liver tumors; however, we need another system for hepatolithiasis. Therefore, we developed a novel difficulty scoring system (nDSS) and validated its use for predicting postoperative outcomes. Materials and Methods: This was a retrospective study. We used clinical data of 123 patients who underwent LLR for hepatolithiasis between 2003 and 2021. We analyzed the data to determine which indices were associated with operation time or estimated blood loss (EBL) to measure the surgical difficulty. We validated the nDSS in terms of its ability to predict postoperative outcomes, namely red blood cell (RBC) transfusion, postoperative hospital stay (POHS), and major complications defined as grade ≥IIIa according to the Clavien−Dindo classification (CDC). Results: The nDSS included five significant indices (range: 5−17; median: 8). The RBC transfusion rate (p < 0.001), POHS (p = 0.002), and major complication rate (p = 0.002) increased with increasing nDSS score. We compared the two groups of patients divided by the median nDSS (low: 5−7; high: 8−17). The operation time (210.7 vs. 240.7 min; p < 0.001), EBL (281.9 vs. 702.6 mL; p < 0.001), RBC transfusion rate (5.3% vs. 37.9%; p < 0.001), POHS (8.0 vs. 13.3 days; p = 0.001), and major complication rate (8.8% vs. 25.8%; p = 0.014) were greater in the high group. Conclusions: The nDSS can predict the surgical difficulty and outcomes of LLR for hepatolithiasis and may help select candidates for the procedure and surgical approach.

Predicting Intraoperative Difficulty of Open Liver Resections: The DIFF-scOR Study, An Analysis of 1393 Consecutive Hepatectomies From a French Multicenter Cohort

OBJECTIVE

The aim of this study was to build a predictive model of operative difficulty in open liver resections (LRs).

SUMMARY BACKGROUND DATA

Recent attempts at classifying open-LR have been focused on postoperative outcomes and were based on predefined anatomical schemes without taking into account other anatomical/technical factors.

METHODS

Four intraoperative variables were perceived by the authors as to reflect operative difficulty: operation and transection times, blood loss, and number of Pringle maneuvers. A hierarchical ascendant classification (HAC) was used to identify homogeneous groups of operative difficulty, based on these variables. Predefined technical/anatomical factors were then selected to build a multivariable logistic regression model (DIFF-scOR), to predict the probability of pertaining to the highest difficulty group. Its discrimination/calibration was assessed. Missing data were handled using multiple imputation.

RESULTS

HAC identified 2 clusters of operative difficulty. In the "Difficult LR" group (20.8% of the procedures), operation time (401 min vs 243 min), transection time (150 vs.63 minute), blood loss (900 vs 400 mL), and number of Pringle maneuvers (3 vs 1) were higher than in the "Standard LR" group. Determinants of operative difficulty were body weight, number and size of nodules, biliary drainage, anatomical or combined LR, transection planes between segments 2 and 4, 4, and 8 or 7 and 8, nonanatomical resections in segments 2, 7, or 8, caval resection, bilioentric anastomosis and number of specimens. The c-statistic of the DIFF-scOR was 0.822. By contrast, the discrimination of the DIFF-scOR to predict 90-day mortality and severe morbidity was poor (c-statistic: 0.616 and 0.634, respectively).

CONCLUSION

The DIFF-scOR accurately predicts open-LR difficulty and may be used for various purposes in clinical practice and research.

Validation of a difficulty scoring system for laparoscopic liver resection in hepatolithiasis

BACKGROUND

A difficulty scoring system (DSS) based on the extent of liver resection, tumor location, liver function, tumor size, and tumor proximity to major vessels was previously developed to assess the difficulty of laparoscopic liver resection (LLR). Recently, we proposed a modified DSS for patients who undergo LLR for intrahepatic duct (IHD) stones. In this study, we validated the modified DSS for LLR for IHD stones.

METHODS

We reviewed the clinical data of 121 patients who underwent LLR for IHD stones between July 2003 and November 2015 and validated the modified DSS in patients who underwent LLR according to their surgical outcomes. We divided the patients into subgroups according to their scores and compared the surgical outcomes, including hospital stay, operation time, blood loss, transfusion rate, and the postoperative complication rate and grade, among the subgroups of patients.

RESULTS

The DSS score ranged from 3 to 12 in LLR for IHD stones. The operation time (P < 0.001) significantly increased according to the DSS score. The median hospital stay after surgery (P = 0.024) and transfusion rate (P = 0.001) were significantly different among subgroups of patients divided by their difficulty scores. When we divided the patients into two groups based on the side of liver of resected, the operation time (P < 0.001), mean difficulty score (P < 0.001), and blood loss (P = 0.041) were greater in patients who underwent right liver resection.

CONCLUSIONS

The surgical difficulty varies among patients undergoing the same LLR procedure for IHD stones. The modified DSS for IHD stones can effectively predict the surgery outcomes and complications of LLR.

Comparison of the Extent Classification and the New Complexity Classification of Hepatectomy for Prediction of Surgical Outcomes: a Retrospective Cohort Study

BACKGROUND

In predicting the risk for posthepatectomy complications, hepatectomy is traditionally classified into minor or major resection based on the number of resected segments. Recently, a new hepatectomy complexity classification was proposed. This study aimed to compare the value of the traditional and that of the new classification in perioperative outcomes prediction.

METHODS

Demographics, perioperative laboratory tests, intraoperative and postoperative outcomes, and follow-up data of patients with hepatocellular carcinoma who underwent liver resection were retrospectively analyzed.

RESULTS

A total of 302 patients were included in our study. Multivariable analysis of intraoperative variables showed that the complexity classification could independently predict the occurrence of blood loss > 800 mL, operation time > 4 h, intraoperative transfusion, and the use of Pringle's maneuver (all p < 0.05). For postoperative outcomes, the high-complexity group was independently associated with severe complications, and hepatic-related complications (all p < 0.05); the traditional classification was independently associated only with posthepatectomy liver failure (PHLF) (p = 0.004).

CONCLUSIONS

Complexity classification could be used to assess the difficulty of surgery and was independently associated with postoperative complications. The traditional classification did not reflect operation complexity and was associated only with PHLF.

Laparoscopic Liver Resection Difficulty Score-a Validation Study

OBJECTIVE(S)

The technical complexity of laparoscopic liver resection (LLR) poses unique challenges distinct from open surgery. An objective scoring system was developed that preoperatively quantifies the difficulty of LRR to help guide surgeon decision-making regarding the feasibility and safety of minimally invasive approaches. The aim of this multiinstitutional study was to externally validate this scoring system.

METHODS

Patients who underwent LLR at two institutions were reviewed. LLR difficulty score (LDS) was calculated based on patient, tumor, and anatomic characteristics by two independent, blinded hepatobiliary surgeons. Surrogates of case complexity (e.g., conversion rate, operative time) were used for validation of this index.

RESULTS

From 2006 to 2016, 444 LLR were scored as low (n = 94), intermediate (n = 98), and high difficulty (n = 152) with respective conversion rates of 5.3%, 15.7%, and 25%. Cases of higher LDS correlated with larger mean blood loss (203 ml vs. 331 ml vs. 635 ml). Mean operative and Pringle maneuver used were associated with increasing LDS (155 min vs. 202 min vs. 315 min and 14.4% vs. 29.7% vs. 45.1% respectively). These operative surrogates of difficulty correlated significantly with the LDS (all p < 0.0001).

CONCLUSIONS

This comprehensive external validation of the LDS is robust and applicable in diverse patient populations. This LDS serves as a useful objective predictor of technical difficulty for LLR to help surgeons in selecting patients according to their individual operative experience and is valuable for preoperative risk estimation and stratification in randomized trials.

A Survey of Clinician Decision Making When Identifying Swallowing Impairments and Determining Treatment

PURPOSE

Speech-language pathologists (SLPs) are the primary providers of dysphagia management; however, this role has been criticized with assertions that SLPs are inadequately trained in swallowing physiology (Campbell-Taylor, 2008). To date, diagnostic acuity and treatment planning for swallowing impairments by practicing SLPs have not been examined. We conducted a survey to examine how clinician demographics and swallowing complexity influence decision making for swallowing impairments in videofluoroscopic images. Our goal was to determine whether SLPs' judgments of swallowing timing impairments align with impairment thresholds available in the research literature and whether or not there is agreement among SLPs regarding therapeutic recommendations.

METHOD

The survey included 3 videofluoroscopic swallows ranging in complexity (easy, moderate, and complex). Three hundred three practicing SLPs in dysphagia management participated in the survey in a web-based format (Qualtrics, 2005) with frame-by-frame viewing capabilities. SLPs' judgments of impairment were compared against impairment thresholds for swallowing timing measures based on 95% confidence intervals from healthy swallows reported in the literature.

RESULTS

The primary impairment in swallowing physiology was identified 67% of the time for the easy swallow, 6% for the moderate swallow, and 6% for the complex swallow. On average, practicing clinicians mislabeled 8 or more swallowing events as impaired that were within the normal physiologic range compared with healthy normative data available in the literature. Agreement was higher among clinicians who report using frame-by-frame analysis 80% of the time. A range of 19-21 different treatments was recommended for each video, regardless of complexity.

CONCLUSIONS

Poor to modest agreement in swallowing impairment identification, frequent false positives, and wide variability in treatment planning recommendations suggest that additional research and training in healthy and disordered swallowing are needed to increase accurate dysphagia diagnosis and treatment among clinicians.

Prediction of surgical outcomes of laparoscopic liver resections for hepatocellular carcinoma by defining surgical difficulty

BACKGROUND

Several classification systems for assessing the surgical difficulty of laparoscopic liver resection (LLR) have been proposed. We evaluated three current classification systems, including traditional Major/Minor Classification, Complexity Classification, and the Difficulty Scoring System for predicting the surgical outcomes after LLR.

METHODS

We reviewed the clinical data of 301 patients who underwent LLR for hepatocellular carcinoma between March 1, 2004 and June 30, 2015. We compared the intraoperative, pathologic, and postoperative outcomes according to the three classifications. We also compared the prognostic value of the three classifications using receiver operating characteristic (ROC) curves.

RESULTS

The Major/Minor Classification, Complexity Classification, and the Difficulty Scoring System efficiently differentiated surgical difficulty in terms of blood loss (P = 0.001, P = 0.009, and P < 0.001, respectively) and operation time (all P < 0.001). Regarding intraoperative outcomes, the Difficulty Scoring System and Complexity Classification successfully differentiated the transfusion rate (P = 0.001 and P < 0.001, respectively). However, only the Complexity Classification adequately predicted severe postoperative complications (P = 0.032), the severity of complications (P < 0.001), and the length of hospital stay (P = 0.005). In ROC curve analysis, the Complexity Classification (area under the curve [AUC] = 0.611) outperformed the Major/Minor Classification (AUC = 0.544) and the Difficulty Scoring System (AUC = 0.530) for predicting severe postoperative complications. None of the classification systems predicted recurrence or patient survival.

CONCLUSION

The Complexity Classification was superior to the other methods for assessing surgical difficulty and predicting complications after LLR for hepatocellular carcinoma.

Completion of a Liver Surgery Complexity Score and Classification Based on an International Survey of Experts

BACKGROUND

Liver resections have classically been distinguished as "minor" or "major," based on number of segments removed. This is flawed because the number of segments resected alone does not convey the complexity of a resection. We recently developed a 3-tiered classification for the complexity of liver resections based on utility weighting by experts. This study aims to complete the earlier classification and to illustrate its application.

STUDY DESIGN

Two surveys were administered to expert liver surgeons. Experts were asked to rate the difficulty of various open liver resections on a scale of 1 to 10. Statistical methods were then used to develop a complexity score for each procedure.

RESULTS

Sixty-six of 135 (48.9%) surgeons responded to the earlier survey, and 66 of 122 (54.1%) responded to the current survey. In all, 19 procedures were rated. The lowest mean score of 1.36 (indicating least difficult) was given to peripheral wedge resection. Right hepatectomy with IVC reconstruction was deemed most difficult, with a score of 9.35. Complexity scores were similar for 9 procedures present in both surveys. Caudate resection, hepaticojejunostomy, and vascular reconstruction all increased the complexity of standard resections significantly.

CONCLUSIONS

These data permit quantitative assessment of the difficulty of a variety of liver resections. The complexity scores generated allow for separation of liver resections into 3 categories of complexity (low complexity, medium complexity, and high complexity) on a quantitative basis. This provides a more accurate representation of the complexity of procedures in comparative studies.