Progress on Laennec's capsule guidance for hepatobiliary surgery

Abstract

Anatomic resection remains a fundamental principle in the surgical management of hepatobiliary diseases, whether performed through traditional open surgery or advanced minimally invasive approaches such as laparoscopic or robotic-assisted techniques. However, a universally accepted and clearly defined anatomical framework for intraoperative anatomical delineation remains lacking. The growing clinical adoption of Laennec membrane-guided anatomical strategies has been associated with notable improvements in surgical efficacy and anatomical precision. This approach facilitates clear identification of anatomical layers, enhances visualization of key landmarks, and enables the execution of precise anatomical resections. As a result, it promotes standardization and reproducibility across surgical procedures. This article presents a comprehensive review of operative techniques and critical technical considerations for Laennec membrane-guided anatomical procedures in hepatobiliary surgery, establishing a three-dimensional anatomical foundation for clinical practice to support the standardization and broader adoption of precision-oriented hepatobiliary surgical methodologies.

1. Introduction

Anatomical landmarks, spatial orientation, and laminar anatomy are fundamental considerations for intraoperative navigation in hepatobiliary surgery. Historically, research efforts have centered on hepatic macroanatomy, particularly lobar partitioning and segmental architecture. However, significant interindividual variability in hepatobiliary anatomy has hindered the establishment of standardized anatomical definitions for resection landmarks.¹ Advancements in laparoscopic hepatobiliary surgery have encouraged the adoption of dorsal, cranial, and caudate lobe approaches for hepatic resections, improving procedural efficiency and oncological outcomes.² Precise intraoperative delineation of anatomical planes has been shown to reduce the operative duration, enhance the completeness of lymphadenectomy, and lower postoperative morbidity. Traditional surgical exposure has focused primarily on major vasculobiliary structures, often overlooking the critical role of parenchymal and interfascial planes in achieving dissection precision. Recent studies have redirected attention to the microanatomical features of Laennec's capsule, highlighting its value as a surgical landmark.3, 4, 5

The recognition and clinical application of Laennec's capsule as a key anatomical guide—particularly in anatomic liver resection (ALR)—has transformed laparoscopic techniques, including hepatic mobilization, retrohepatic tunnel creation, and systematic dissection of hepatic pedicles and venous structures.⁴ A multicenter cohort study confirmed the Laennec approach as a standardized technique for ALR.⁶ Moreover, this strategy has demonstrated broader applicability in complex scenarios, including repeat hepatectomy,⁷ challenging cholecystectomies,⁸ and suspected gallbladder malignancy,⁹ as discussed in later sections.

Building on these developments, this review synthesizes clinical evidence and recent technical innovations to offer an integrated, evidence-based framework for refining anatomically guided surgical protocols in hepatobiliary surgery.

2. History of Laennec's capsule in the liver

The visceral peritoneum invests the liver, gallbladder, and extrahepatic bile ducts, reflecting at defined anatomical junctions—including the bare area of the liver, the second hepatic hilum, the ligamentum venosum, and the first hepatic hilum—to form the right and left triangular ligaments, the falciform ligament, and the hepatogastric ligament. However, this investment is incomplete: regions such as the bare area and the caudate lobe adjacent to the inferior vena cava remain devoid of peritoneal coverage. In 1802, the French physician René Laennec identified a novel membranous structure distinct from the visceral peritoneum, later termed the Laennec membrane. Histologically, this structure encases the hepatic parenchyma and Glisson's capsule, extending as a fibrous sheath around the extrahepatic hilar structures.^10,11

In 2008, Hayashi et al. used immunohistochemical techniques to characterize a continuous fibrous membrane enveloping the liver parenchyma. This structure originates extrahepatically, invests the hepatic pedicle during its intrahepatic course, and sheathes the hepatic veins along their extrahepatic trajectory.¹² In 2017, Sugioka et al. proposed that the Laennec membrane could serve as an anatomical plane for dissociating Glisson's pedicle.³ Morphological studies in 2018 confirmed that the Laennec membrane forms a continuous envelope around the liver parenchyma, with potential anatomic spaces between the membrane and adjacent structures. These avascular planes offer reproducible pathways for both extrahepatic and intrahepatic dissection.⁴ In 2019, Shirata et al.¹³ clarified that the Laennec membrane is confined to the interface between hepatic veins and parenchyma, without structural continuity to the adventitia of extrahepatic veins. In 2023, further morphological studies confirmed a bilaminar configuration of the Laennec membrane surrounding hepatic veins, suggesting that intraoperative stratification of this membrane improves technical feasibility during ALR.^14,15 Advancing insights into hepatic microanatomy have established the Laennec membrane as a pivotal surgical landmark, with membrane-guided techniques improving intraoperative navigation and helping to standardize ALR.^4,9,16, 17, 18, 19 The key milestones in the evolution of hepatobiliary surgery, including open ALR and laparoscopic liver surgery—specifically the trajectory of Laennec capsule guidance from theoretical discovery to clinical innovation—are mapped chronologically in Table 1.

Table 1.

Timeline of hepatobiliary surgical development.

Era	Key Development	Significance
Early-Mid 20th Century	Empirical liver surgery	Absence of standardized anatomy; procedures based on individual experience
1957	Couinaud classification10	Defined segmental liver anatomy; established foundation for anatomic liver resection (ALR)
1980s–1990s	Open ALR20	Widely adopted; portal territory-guided resections as the oncologic standard
2000s	Laparoscopic liver surgery21	Microinvasive approaches expanded to minor hepatectomies; reemphasized anatomical precision
2017	Laennec-based dissection3	Identified Laennec membrane as a reproducible dissection plane
2019	First application of Laennec approach in laproscopic ALR4	Established membrane-guided ALR; enhanced safety and reproducibility
2023	Application in suspected gallbladder cancer9	Enabled safe, precise staging and immediate radical surgery via Laennec approach
2025	Multicenter validation and standardization of Laennec approach for ALR6	Laennec approach as a standardized technique for ALR

ALR, anatomic liver resection.

3. Paradigm shift in ALR: standardizing the Laennec approach and its multidisciplinary integration

ALR remains a cornerstone in the curative treatment of primary and metastatic liver malignancies.²² However, key procedural steps—such as hepatic pedicle isolation, venous dissection, and retrohepatic mobilization—often lack standardized technical protocols, contributing to variability in surgical outcomes.^5,19,23 Achieving optimal oncological and functional outcomes requires a thorough understanding of both hepatic macro- and microanatomy. Although Glissonian pedicle dissection is widely practiced, the absence of consensus on the ideal dissection plane—particularly regarding the membranous architecture surrounding the Glissonian sheath—has hindered procedural reproducibility. In 2017, Sugioka et al.³ proposed the Laennec membrane as a laminar guide for Glissonian pedicle dissection.

The Laennec approach was subsequently developed to standardize Glissonian pedicle and hepatic vein dissection,^4,16 and it has since been adapted to robotic platforms with enhanced instrument articulation. Cumulative evidence from more than 500 laparoscopic ALR cases supports its reproducibility. In Chinese cohorts, integration with indocyanine green fluorescence has refined intraoperative localization.²⁴ International studies have validated its utility in colorectal liver metastases, where Laennec-guided left hepatectomy achieves complete tumor resection with negative margins (R0 resection) at rates exceeding 90% while preserving maximal parenchyma,²⁵ and in pediatric donor hepatectomy, where it facilitates standardized Glissonian-guided resections.^26,27 Furthermore, the Laennec–Glissonian paradigm enables controlled parenchymal transection along avascular planes, supporting complex resections such as bisegmentectomies (S3/S4b),²⁸ S7 segmentectomies,²⁹ and laparoscopic sectoral resections, including middle hepatic lobe,³⁰ right posterior,^31,32 and right anterior sectorectomies.³³ A prospective multicenter trial (ChiCTR2000038854) involving 445 patients across 11 Chinese centers evaluated Laennec membrane-guided ALR, with its outcomes, advantages, and limitations summarized in Table 2.⁶ This approach enables stratified anatomical dissection and systematizes ALR into a reproducible and standardized framework. By integrating anatomical insights, clinical validation, and emerging technologies, the Laennec approach fosters methodological consistency across hepatobiliary surgeries.^4,16,17,19

Table 2.

Summary of clinical trials using the Laennec approach for anatomical liver resection (https://www.chictr.org.cn/showproj.html?proj=62183) and laparoscopic cholecystectomy for gallbladder neoplasms (https://www.chictr.org.cn/showproj.html?proj=130837).

Clinical Tial ID. and status	Sample size	Outcomes	Advantages	Limitations
ChiCTR2000038854 Finished6	445 patients (11 centers)	Laennec approach optimized intraoperative efficiency with no significant postoperative benefits.	(1)Standardized technique using Laennec's capsule landmark (2)Shorter operative times (3)Laennec gap aids candidate selection (4)Superior robotic applicability	(1)Non-randomized (2)Heterogeneous pathologies (3)Small subgroups (4)No plateau in learning curve (5)Intraoperative benefits did not improve postoperative recovery/survival
ChiCTR2100049301 Ongoing9	17 patients (2 centers)	(1)All 17 cases underwent laparoscopic cholecystectomy via the Laennec approach. (2)Intraoperative staging guided immediate radical resection in three cancers. (3)No recurrence at 6 months.	(1)Clear anatomical plane (Laennec capsule) facilitated safe dissection and complete gallbladder removal including adventitia. (2)Enabled accurate staging and prompt shift to radical resection when needed.	(1)Single-arm, non-randomized pilot study. (2)Small sample size, short follow-up period (6 months). (3)No long-term oncological outcomes reported.

A schematic overview of its clinical applications across diverse hepatobiliary procedures—including ALR, robotic-assisted resections, repeat hepatectomy, difficult cholecystectomies, and suspected gallbladder carcinoma—is presented in Fig. 1.

Fig. 1.

Schematic summary of the clinical applications of the Laennec approach in hepatobiliary surgery.

This figure illustrates the integration of the Laennec approach across a range of procedures, including anatomical liver resection, robotic-assisted liver resection, repeat hepatectomy, high-risk cholecystectomy, and surgery for suspected gallbladder cancer.

3.1. Application of the Laennec approach in anatomical hepatectomy

The standardized procedural algorithm for Laennec-guided hepatectomy—covering key steps for both right and left resections—has been detailed in prior technique-focused publications.^4,15,16,24 Representative intraoperative views of Laennec-guided anatomical liver resections, including exposure of the middle hepatic vein (Fig. 2A) and the right hepatic vein (Fig. 2B), are shown. Lai et al.³⁴ conducted a propensity score-matched cohort study validating the perioperative benefits of Laennec-guided laparoscopic left hepatectomy, confirming its safety, oncological efficacy, and reproducibility in Chinese populations. International cohorts have further corroborated that the Laennec membrane encases the entire hepatic vein, and that cranial access via the Laennec approach enables safer and more controlled dissection during laparoscopic left hepatectomy.³⁵ Additional studies have leveraged the anatomic potential space between the Laennec membrane and the Glissonian pedicle to further standardize laparoscopic ALR, reinforcing its role in facilitating consistent laparoscopic left hepatectomy.³⁶ Intraoperative dissection within the Laennec–Glissonian interface allows for circumferential pedicle control and the creation of sharp ischemic demarcation, guiding precise segmental resection.⁴ Clinical outcomes from laparoscopic resections near the gallbladder bed also demonstrate enhanced visualization and improved margin control.³⁷ Compared with conventional methods, Laennec-guided ALR shows improvements in operative time, portal occlusion duration, and hospitalization length.¹⁶

Fig. 2.

Representative intraoperative views of hepatobiliary procedures utilizing the Laennec approach.

(A) Exposure of the middle hepatic vein (MHV) during laparoscopic right hemihepatectomy, with Laennec's capsule indicated by the elliptical shadow. (B) Exposure of the right hepatic vein (RHV) during laparoscopic right posterior hepatectomy, with Laennec's capsule indicated by the elliptical shadow. Panels A and B are adapted and modified from Hu Y, Shi J, Wang SH et al. Laennec's approach for laparoscopic anatomic hepatectomy based on Laennec's capsule. BMC Gastroenterol. 2019, 19(1): 194. doi: 10.1186/s12876-019-1107-9.⁴ Licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). (C) Liver mobilization during robotic-assisted hepatectomy, with Laennec's capsule delineated by the elliptical shadow. (D) Ligation of a short hepatic vein using a titanium clip during robotic-assisted liver resection, with Laennec's capsule marked by the elliptical shadow. (E) Blunt dissection of adhesions between the bare area of the liver and the diaphragm via the Laennec approach (located according to the shadow) during repeat hepatectomy. (F) Separation of adhesions between the diaphragm and the right liver using the Laennec membrane (located according to the shadow) during repeat hepatectomy. (G, H) Gallbladder dissection from the gallbladder bed using the Laennec approach in suspected gallbladder cancer. The red line indicates the dissection path, and the shaded area is covered by the Laennec capsule. Panels G and H are adapted and modified from Ouyang B, Zhang LZ, Cao YJ et al. Laparoscopic cholecystectomy based on Laennec approach via the cystic plate with lymphadenectomy in Calot's triangle for gallbladder neoplasms: Initial experience and technical details. iLIVER. 2023, 2(4): 202–207. doi: 10.1016/j.iliver.2023.10.001.⁹ Licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).

Thus, the Laennec membrane supports both extrahepatic mobilization and intrahepatic dissection, reinforcing its value in standardized anatomical hepatectomy.¹⁶

3.2. Application of the Laennec approach in robotic-assisted liver resection

The rapid evolution of minimally invasive platforms has positioned robotic-assisted hepatobiliary surgery as a mainstay for complex liver resections, combining procedural versatility with enhanced anatomical precision. While sharing core principles with laparoscopy, robotic systems offer superior instrument articulation, tremor filtration, and three-dimensional stereoscopic visualization—features that enhance dissection accuracy within Laennec-defined planes.

The Laennec approach has been adopted in robotic-assisted liver resection, leveraging these technical advantages. Fig. 2C and D illustrates liver mobilization and short hepatic vein ligation using the Laennec approach during robotic procedures. Although the foundational principles align with laparoscopic ALR, robotic systems enhance precision, particularly around vascular and biliary structures. In right hepatectomy, in situ resection strategies often utilize Laennec planes to facilitate safe hepatic vein ligation and controlled retrograde mobilization. Left-sided resections benefit from dorsal-to-ventral dissection guided by Laennec landmarks.

Despite growing adoption, inter-institutional variability persists, highlighting the need for procedural standardization. Since 2021, data from more than 300 robotic-assisted liver resections have contributed to refining Laennec-guided techniques and establishing workflows for robotic ALR. Additionally, Laennec-guided robotics has expanded the indications for minimally invasive surgery to include gallbladder cancer and hilar cholangiocarcinoma, representing a significant technical advancement in the field.

3.3. Laennec membrane-guided dissection in repeat hepatectomy: Overcoming perihepatic adhesions through anatomical delineation

Regardless of the surgical approach used for liver resection, hepatic mobilization is a prerequisite because it ensures exposure of critical vasculobiliary structures and adequate oncological margins.²² Laparoscopic mobilization enhances visualization of the hepatic pedicle and vascular anatomy, delineates resection boundaries, and enables precise hemodynamic control, all of which contribute to safe parenchymal resection.¹

Repeat hepatectomies—performed for recurrent malignancies, hepatolithiasis, or anastomotic strictures—are complicated by fibrotic adhesions that obscure anatomical planes. Postoperative adhesions commonly involve the diaphragm, gastrointestinal tract, and retroperitoneal organs, often obliterating the Laennec potential space and increasing the risk associated with dissection. In such cases, the original perihepatic Laennec space may be effaced, making mobilization more difficult and heightening the risk of iatrogenic injury.⁴

To address these challenges, alternative approaches such as the round ligament, gallbladder fossa, or Rouvière's groove have been proposed. However, these lack anatomically defined dissection planes.⁴ While they can partially expose the first hepatic hilum, they provide limited access to deeper hilar structures, restricting their usefulness in complex resections. Moreover, their reliance on operator-dependent strategies rather than fixed anatomical landmarks introduces variability in outcomes. Thus, the identification and confirmation of anatomical layers during liver mobilization remain essential. Emerging evidence supports the utility of the Laennec approach in salvage resections, including a reported case of curative-intent middle hepatic lobe resection performed a decade after colorectal metastasectomy.³⁸ Laennec-guided techniques have also been applied in associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedures for hepatocellular carcinoma, enabling safe parenchymal partitioning.³⁹

Clinical experience affirms the safety and efficacy of Laennec-guided repeat hepatectomies in reoperative settings. Although previous surgeries often result in dense adhesions between the visceral peritoneum and surrounding organs, residual Laennec planes may persist near the hepatic hilum, allowing for careful dissection to access hilar structures. By contrast, the perihepatic space at the bare area is frequently obliterated, requiring dissection within the lamellar layers of the Laennec membrane or along its interface with the liver parenchyma.¹⁶ As a definitive anatomical roadmap, the Laennec membrane delineates dissection planes, enabling stratified tissue separation while minimizing collateral damage. Blunt dissection of perihepatic adhesions using the Laennec plane in repeat hepatectomy is illustrated in Fig. 2E and F. This systematic approach facilitates accurate landmark identification, reduces hemorrhagic complications, and preserves adjacent organ integrity. As such, the Laennec approach represents a paradigm shift in reoperative hepatectomy, transforming high-risk adhesiolysis into a standardized, anatomy-driven procedure.

4. Expansion of the Laennec approach in hepatobiliary surgery: Laennec membrane guidance for difficult cholecystectomies

Inflammatory gallbladder disease leads to anatomical distortion, significantly increasing intraoperative complexity. These alterations elevate the risk of complications, particularly bile duct injury and hemorrhage.⁴⁰ Mirizzi syndrome, caused by impacted calculi or benign strictures at the gallbladder neck or cystic duct, results in extrinsic compression or inflammatory stenosis of the biliary tree with progressive obstruction. Despite advances in preoperative imaging, surgical management remains largely experience-driven, relying on intraoperative judgment rather than standardized anatomical protocols.⁴¹ For type II Mirizzi syndrome, conventional approaches such as choledochojejunostomy carry considerable morbidity,⁴² while newer techniques may result in incomplete drainage or postoperative strictures.⁴³ These methods often fail to achieve adequate cystic plate mobilization, and infundibular reconstruction may result in geometric mismatch with the native bile duct, frequently necessitating secondary interventions. By contrast, the Laennec approach allows for en bloc resection of the cystic plate and gallbladder neck, followed by anatomical tubular reconstruction of the common bile duct—preserving biliary continuity and luminal integrity without resorting to more invasive procedures.

Laennec-guided cholecystectomy for type II Mirizzi syndrome has been documented, demonstrating cystic plate dissection and biliary reconstruction using this approach.⁸ Beyond Mirizzi syndrome, similar challenges occur in xanthogranulomatous cholecystitis, gangrenous cholecystitis, and other inflammatory conditions where fibrosis obscures the anatomical boundaries of Calot's triangle.⁴² The stratified anatomical separation provided by the Laennec membrane helps delineate Calot's triangle, safeguarding critical structures. This anatomical precision reduces the risk of iatrogenic bile duct injury, mitigates postoperative morbidity, and raises the safety of these complex procedures to levels approaching those of elective cholecystectomy.

5. Laennec membrane-driven resection in suspected gallbladder cancer: optimizing oncologic precision and staging accuracy

Advances in cross-sectional imaging and standardized diagnostic algorithms have shifted clinical focus toward the preoperative identification of suspected gallbladder malignancies, reducing reliance on incidental intraoperative discovery.⁴⁴ However, preoperative differentiation between tissue in situ (Tis), T1, and T2 lesions remains limited, necessitating intraoperative frozen-section analysis for definitive staging.⁴⁵ Current guidelines recommend simple cholecystectomy for T1a tumors (confined to the mucosa), while T1b, T2, and T3 tumors require extended resection—including hepatic segments IVb/V and lymphadenectomy—to optimize survival outcomes.⁴⁶ In T1b or T2 tumors managed with conventional subserosal cholecystectomy, several risks arise. First, postoperative staging may be inaccurate because of insufficient margin assessment. Second, intraoperative manipulation may lead to tumor dissemination, increasing the risk of implantation metastasis. Subserosal dissection performed without clear anatomical guidance increases the likelihood of iatrogenic tumor fragmentation, potentially precluding curative-intent resection. Therefore, a novel anatomically guided approach is needed to ensure complete gallbladder removal, accurate staging, and the timely initiation of curative treatment for T1b–T2 gallbladder cancer.

The gallbladder bed features an avascular interface between the gallbladder serosa and the Laennec membrane covering the liver parenchyma, offering a natural anatomical plane for en bloc resection. Fig. 2G and H demonstrates Laennec-guided dissection of the gallbladder bed in suspected gallbladder cancer, highlighting this avascular dissection plane. Laennec-guided cholecystectomy facilitates R0 resection margins along with lymphadenectomy in Calot's triangle, ensuring oncologic completeness. Preliminary data from 17 suspected cases (including 4 T2-confirmed tumors) showed that curative resection was achieved without overtreatment of benign pathology, avoiding unnecessary hepatic resection in 76.5% of patients.

This approach minimizes intraoperative trauma to the gallbladder and surrounding structures, reduces bile leakage, and enhances the accuracy of pathological staging. It supports timely implementation of appropriate oncologic strategies aligned with current clinical guidelines, thereby improving patient outcomes. Additionally, the technique is being further evaluated in ongoing clinical research (ChiCTR2100049301).⁹ An initial summary of this trial is provided in Table 2, offering insights into the outcomes, benefits, and implementation challenges associated with Laennec membrane-driven resection in suspected gallbladder cancer.

6. Limitations and challenges

Despite the promising potential of the Laennec capsule-guided approach in hepatobiliary surgery, several limitations and challenges must be acknowledged. Anatomical variability among patients—such as differences in the thickness and adherence of the capsule, or the presence of pathological conditions like cirrhosis or inflammation—can complicate the identification and dissection of Laennec planes. These variations may lead to increased operative time and technical difficulties during surgery. Widespread adoption of the approach across different centers also presents challenges due to variability in surgical expertise, familiarity with minimally invasive techniques, and differing levels of awareness regarding the Laennec capsule concept. Institutions with limited experience in advanced laparoscopic or robotic hepatobiliary procedures may require additional training and resources to achieve competency in this technique. Mastering the Laennec capsule-guided approach entails a substantial learning curve. Surgeons must develop a nuanced understanding of the relevant anatomy and gain technical proficiency in precise dissection within Laennec-defined planes. Notably, analysis of the learning curve in the prospective trial (ChiCTR2000038854) revealed no clear proficiency plateau, suggesting heterogeneity in operator skill and highlighting the current absence of standardized competency metrics for the Laennec approach.⁶ Additionally, preoperative imaging interpretation (particularly identification of the Laennec gap) and intraoperative recognition of anatomical landmarks demand a high level of expertise. These factors may limit the consistent application and broader institutional adoption of the Laennec approach.

7. Future directions: from anatomical innovation to universal standardization

The Laennec membrane has emerged as a transformative anatomical framework in hepatobiliary surgery, facilitating stratified dissection of hepatic and biliary planes and contributing to the standardization of procedural workflows in ALR. Its integration into clinical practice enhances intraoperative decision-making, reduces technical variability, and promotes multidisciplinary collaboration. Looking ahead, future studies should explore its application in trauma reconstruction and living donor hepatectomy. Prospective trials (such as ChiCTR2100049301) and the development of simulation-based training programs will be critical in driving the universal standardization of the Laennec approach.

CRediT authorship contribution statement

Decai Yu: Writing – review & editing, Funding acquisition, Conceptualization. Leizhou Xia: Writing – original draft, Conceptualization.

Informed consent

Not applicable.

Data availability statement

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Ethics statement

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Declaration of Generative AI and AI-assisted technologies in the writing process

Not applicable.

Funding

This work was supported by grants from the National Natural Science Foundation of China (No. 82372834).

Declaration of competing interest

The authors and funder declare that there are no conflicts of interest.