Introduction

Laparoscopic liver surgery, a widely accepted standard surgical practice for the management of liver neoplasm, has evolved over the past two decades, and the procedure has expanded from initial local hepatectomy to anatomical hepatectomy. Laparoscopic hepatic resection has attained an equivalent status of safety and efficacy as conventional open surgeries, but the expansion of the procedure depends on the experienced surgical team in hepatobiliary surgery, laparoscopic skills, and specialized centers with advanced laparoscopic surgery. Nevertheless, laparoscopic anatomical hemihepatectomies (LAH) are very challenging and technically demanding procedures. Notably, for deep-seated or invisible lesions, the development of LAH is greatly limited because of their deep anatomical position, surgical complication during exposure of the resection plane, and complexity in identifying the boundary of hemihepatectomy, and difficult hemorrhage control [1, 2]. In LAH, identification and anatomical separation of the Glissonean pedicle (GP) at the hepatic hilum and exposure of the landmark hepatic vein represents the critical steps in deciding the transection plane. However, there is a lack of consensus on the standardized approach to LAH [3].

Laennec’s capsule, the liver’s intrinsic membrane, represents an essential structure for the comprehensive understanding of the surgical anatomy of the liver and standardization of the surgical approach to LAH [4, 5]. Some studies have suggested that there is a gap between the extrahepatic GP and Laennec’s capsule that could be used as an anatomical gap to isolate GP and hepatic vein [6,7,8]. However, LAH based on Laennec’s capsule is rarely reported. Here we described the relevant application of Laennec’s approach for LAH based on Laennec’s capsule and highlighted the surgical anatomical description of the liver and related clinical experience. After that, we retrospectively analyzed the technical details and the surgical outcomes of our standardized approach performed on 15 patients who underwent LAH in our hospital between May 2017 and July 2020. We also investigated the safety and efficacy of this approach to expand our understanding of the membranous anatomy of the liver.

Materials and methods

General information

This study comprised 15 patients with benign or malignant neoplasms or hepatolithiasis who underwent LAH between May 2017 and July 2020. Of the 15 patients, 4 patients were diagnosed with hepatic hemangioma, 2 patients had hepatolithiasis, and 9 patients had primary liver cancer. The mean patient age was 62.1 ± 6.5 years, and four were male. The preoperative liver function of patients was Child-Pugh class A, and the indocyanine green retention rate at 15 min (ICG R15) was less than 10%. There was no apparent surgical contraindication before the surgery. None of the lesions affected the anatomy of the first or the second porta hepatis. Laennec’s approach for LAH was performed during the hemihepatectomy by isolating the GP and hepatic vein. The liver tissue specimens adjacent to the GP, hepatic veins, and inferior vena cava (IVC) were collected for hematoxylin and eosin (H&E) and Mallory’s phosphotungstic acid hematoxylin-eosin staining. The study protocol was approved by the Research Ethics Committee of the First Affiliated Hospital of Kangda College of Nan**g Medical University (Approval number: KY20170513001). This study was performed in accordance with the Declaration of Helsinki, and written informed consent was obtained from each patient before surgery.

Surgical methods

All procedures were performed under general anesthesia. Patients were placed in the supine position for resection. The 5-port technique was performed. The pneumoperitoneum pressure was maintained at 14 mmHg. The central venous pressure was maintained between 0 and 3 cm H2O during surgery in all cases. The hepatoduodenal ligament was encircled with extraperitoneal blocking tape through Winslow’s foramen by the Pringle maneuver. For right hemihepatectomy, the following procedures were performed: (1) Laennec’s approach for dissection of GP: the hepatic hilar plate was lowered after cholecystectomy. The peritoneum between segment 4 and the surface of GP was incised through Laennec’s capsule. After sufficient dissection, the right GP was ligated using a Goldfinger dissector for traction and transected with a laparoscopic vascular stapler (if the right GP was difficult to dissect, the liver parenchyma dissecting-first method through the hepatic Cantlie line was applied to reveal the root of the right GP [5, 10, 12]. However, we confirmed through H&E and Mallory staining that Laennec’s capsule also covers the branches of the peripheral hepatic vein of the segments II–VIII, and there is a gap between Laennec’s capsule and the veins. In precision liver excision, dissecting Laennec’s capsule gap along the liver venous trunk and its branches can effectively achieve segmental anatomic liver excision.

This study highlights that Laennec’s approach provides a new perspective for laparoscopic anatomical hepatectomy. It is beneficial to the procedure and standardization of laparoscopic anatomical hepatectomy. Laennec’s capsule can be used as an anatomical marker for anatomical hepatectomy, expecting to promote liver surgeons’ understanding of liver membrane anatomy and the development of LAH.

Conclusions

Laennec’s approach is safe and feasible for LAH. Precise isolation of Laennec’s approach based on Laennec’s capsule helps to standardize the surgical techniques for laparoscopic anatomical hepatectomy.