A hepatic hemangioma (HH) is one of the most common benign liver tumors, with incidence ranging from 0.4% to 20% in the general population (1, 2). It develops slowly and has a good prognosis. As for its pathogenesis, some scholars believe that a large number of vascular cells proliferate in the liver during embryonic development, forming a malformed vascular mass that lacks smooth muscle tissue. Furthermore, the changes in the level of acquired endocrine hormones significantly promote its growth (3). Relevant studies suggest that estrogen receptors exist in hepatic hemangioma tissues, and the occurrence and development of hemangiomas are estrogen-dependent. Therefore, the increase in estrogen level caused by female puberty, oral contraceptives, or pregnancy can accelerate the growth of hepatic hemangiomas (4–6). Hepatic hemangiomas can be divided into four histological types, including cavernous hemangioma, capillary hemangioma, sclerosing hemangioma, and hemangioendothelioma, according to the amount of fibrous tissue contained in hemangiomas. A cavernous hemangioma is the most common in clinics (7).

HH is usually asymptomatic and is discovered incidentally by abdominal imaging during routine physical examination. Traditionally, asymptomatic hepatic hemangiomas require no further clinical intervention (8). However, if there is a rapid growth of hemangioma or obvious clinical symptoms such as abdominal pain, compression of adjacent organs, intratumoral bleeding, acute abdomen due to tumor rupture, and Kasabach–Merritt syndrome during the long-term follow-up, further treatment is needed (9–11). Treatment options for HHs are corticosteroid treatment, transcatheter arterial embolization, radiofrequency ablation, surgical resection, and, occasionally, transplantation (12–15). Surgical resection, including segmental hepatectomy and hemangioma enucleation, is the most effective and widely accepted treatment for these symptomatic patients (16, 17). Also, many surgeons favor enucleation for HHs as it is a safe and quick technique with a maximum amount of normal liver parenchyma preserving, low blood loss, and low morbidity and mortality rates for hepatic hemangiomas.

Over the past few decades, with the rapid development of minimally invasive surgery, the continuous innovation of laparoscopic-related instruments and the improvement in endoscopic operation technology, the laparoscopic liver approach has gained widespread acceptance and become the first choice for the treatment of HH. Its safety, efficacy, and advantages have been effectively verified in clinical practice (18–20). However, it still has a high difficulty and risk in laparoscopic surgery for hepatic hemangiomas in special location (Couinaud liver segments I, IVa, VII, and VIII) (21–26), as visualization is the key point in laparoscopic surgery. When HHs are located in these special segments, visualization is limited and it is difficult to reach. Meanwhile, the tumor body is usually adjacent to vessels such as hepatic veins and inferior vena cava and compresses these main vessels. Especially the HH located in segment I has several thin hepatic veins draining directly into the inferior vena cava and is close to the liver hilum. These factors increase the risk of uncontrolled bleeding, which is a threat to patient's life and requires a shift to laparotomy. The aim of this study was to evaluate the safety and efficacy of laparoscopic enucleation for liver hemangiomas in special hepatic segments.

A hepatic hemangioma can generally be observed and requires intervention only if it is symptomatic. Surgical resection is the most effective and widely accepted treatment. Over the past few decades, the laparoscopic liver approach has gained widespread acceptance and become the first choice for the treatment of HH, parallel with the continued evolution of surgical expertise and improved instrumentation. Its safety, efficacy, and advantages have been effectively verified in clinical practice. Relevant clinical studies showed that laparoscopic surgery for HH has the advantages of less intraoperative bleeding, lower postoperative complication rate, faster recovery, and shorter hospital stay than traditional open surgery (27–30). These advantages are mainly attributed to the clear and magnifying vision of the operational field in laparoscopy and the application of laparoscopic energy instruments such as ultrasound scalpels, bipolar electrocoagulation, and argon spraying, which are beneficial to hemostasis.

In terms of the selection of surgical methods, the selected surgical procedures are different according to the size and location of HH. An extremely giant HH of more than 20 cm is typically resected using the open approach (31). As the extremely giant HH occupies most of the intraperitoneal space, leading to limited operating space, it will increase the risk of intraoperative massive hemorrhage and mortality. Laparoscopic left lateral lobectomy has become the standard operation method for patients with hemangiomas in segments II and III (32). For the extrahepatic hemangioma of other liver segments, laparoscopic hemangioma enucleation is preferred. As the hepatic hemangioma grows expansively, it squeezes the surrounding normal liver parenchyma in the process of growth and forms a layer of a fibrous capsule around it. There is a boundary between the fibrous capsule and the normal liver parenchyma. Stripping the hemangioma along this boundary is conducive to retaining more normal liver parenchyma and reducing the incidence of postoperative complications such as bleeding and biliary fistula (33, 34). It was once considered a prohibited area of surgery for patients with HH located in the special hepatic segments (I, IVa, VII, VIII), which had bad visualization and were adjacent to important vessels such as hepatic veins and the inferior vena cava, associating the surgery of HHs in this region to characteristics of “more intraoperative bleeding, more postoperative complications, and high mortality.” With the continued evolution of surgical expertise and improved instrumentation, laparoscopic enucleation of hemangiomas located in the right posterior lobe or caudate lobe of the liver has been carried out and has gradually become a routine operation. However, it is still a big challenge for surgeons and has an extremely high requirement for the tacit cooperation of the team. In this study, the operation time, intraoperative blood loss, and intraoperative blood transfusion rate of the SLG were significantly higher than those of the NLG (p < 0.05). In the postoperative course, the levels of serum transaminase and bilirubin in the early stage showed an increasing trend, reaching a peak on the third or fourth day after the operation, and then gradually decreased to the normal range with the medical therapy. There were no significant differences in biochemical indexes and postoperative complications between the two groups (p > 0.05). However, the patient's exhaust time and postoperative hospital stay of the SLG were significantly longer than that of the NLG. Also, there were no perioperative deaths in the two groups. This result demonstrated that hemangiomas located in special liver segments have a higher risk of intraoperative hemorrhage, but a timely shift to laparotomy can ensure the safety of patients and postoperative recovery.

Based on this study, we have summarized some experiences. First, the fixed combination and skilled operation team are the basis for the successful implementation of complex laparoscopic surgery, especially in the event of severe bleeding and other critical situations during the operation. Mutual trust and effective cooperation between teams are extremely important. Second, it is an important prerequisite to fully expose the tumor body. The liver is an organ rich in blood supply, and its internal pipeline structure is complex. Bleeding often occurs due to blood vessel damage during surgery. The special locations' narrow space and bad visualization make the laparoscopic suture difficult and increase the rate of laparotomy and the risk of death. Therefore, completely freeing the right half of the liver to facilitate exposure is extremely important for the surgical operation and hemostasis. Third, finding and following the boundary between the hemangioma and normal liver parenchyma is the key to enucleation and avoiding hemorrhage. In addition, intermittent blocking of the first hepatic portal can not only reduce hemorrhage during the operation but also can reduce the volume of blood within the HH, facilitating its identification and dissection. Fourth, we should keep a stable attitude and gentle action. The hepatic hemangioma's tissue is relatively soft, especially the cavernous hemangioma. Mechanical touching, pulling, and other operations easily damage the tumor's capsule and lead to bleeding. Therefore, selecting appropriate operating instruments for traction is necessary, and the strength should be kept moderate to avoid membrane tears caused by excessive traction. An aspirator is a good “weapon” for stripping the hemangioma. The aspirator has a round and blunt front end. It is not easy to damage the hemangioma wall and the venous system compressed by the hemangioma when stripping the hemangioma with an aspirator. Meanwhile, keeping the aspirator with tiny suction intermittently helps to maintain a clear vision of the operation area, facilitates the exposure of important vascular structures around the tumor body, and avoids accidental injury and massive bleeding. It is advised not to cut off the vascular structures in a hurry without fully exposing their shapes. This helps us to avoid damaging important blood vessels by mistake. Moreover, this is especially important when a giant hemangioma compresses hepatic veins and other important blood vessels. Fifth, strong psychological quality and prompt decision to a shift to laparotomy assure to maintain the safety of surgery when encountering uncontrollable bleeding.

The present study has several limitations. First, the sample size of the overall study is relatively small. This is the clinical reality of a developing medical center and a single-center study. Second, we lack advanced medical equipment, such as endoscopic ultrasound and cavitation ultrasonic surgical aspirator, and the like. This may have influenced the outcomes. Third, we are in the early stage of such surgery, and the learning curve effect may have influenced the outcomes. A well-designed multicenter study with a large sample size would be ideal in the future.

In conclusion, laparoscopic enucleation of hemangioma in special hepatic segments is difficult and has a critical risk of massive bleeding during surgery. Meanwhile, it is also safe, feasible, and effective. Grasping indications of laparoscopic surgery, good preoperative planning, skilled laparoscopic technique, and tacit teamwork are significant factors for the success of this surgery.