Laparoscopic associating liver partition and portal vein ligation for staged hepatectomy for colorectal liver metastases: A single-center experience

Abstract

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a procedure used for patients with initially unresectable colorectal liver metastases (CRLM). However, the procedure has been reported to be associated with high morbidity and mortality. Laparoscopic ALPPS has recently been reported as a minimally invasive technique that reduces perioperative risks.

AIM

To assess the safety and feasibility of full laparoscopic ALPPS in patients with CRLM.

METHODS

A retrospective analysis was conducted on all consecutive patients with CRLM who underwent full laparoscopic ALPPS at the Sixth Affiliated Hospital of Sun Yat-sen University between March 2021 and July 2024.

RESULTS

Fifteen patients were included, 13 with synchronous liver metastases. Nine patients had more than five liver tumors, with the highest count being 22. The median diameter of the largest lesion was 2.8 cm on preoperative imaging. No extrahepatic metastases were observed. RAS mutations were detected in nine patients, and 14 underwent preoperative chemotherapy. The median increase in future liver remnant volume during the interstage interval was 47.0%. All patients underwent R0 resection. Overall complication rates were 13.3% (stage 1) and 53.3% (stage 2), while major complication rates (Clavien-Dindo ≥ IIIa) were 13.3% (stage 1) and 33.3% (stage 2). No mortality occurred in either stage. The median hospital stay after stage 2 was 10 days.

CONCLUSION

Full laparoscopic ALPPS for CRLM is safe and feasible, with the potential for reduced morbidity and mortality, offering radical resection opportunities for patients with initially unresectable CRLM.

Key Words: Minimally invasive surgery; Laparoscopic surgery; Associating liver partition and portal vein ligation for staged hepatectomy; Colorectal liver metastases; Future liver remnant

Core Tip: This study evaluates the feasibility and safety of full laparoscopic associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in colorectal liver metastases. Among 15 patients, the procedure achieved a 100% radical resection rate with significant future liver remnant hypertrophy (47% median increase). Complication rates were low, particularly in stage 1, with no mortality reported. Laparoscopic modifications minimized invasiveness and enhanced surgical outcomes. Post-ALPPS liver regeneration was substantial, demonstrating the potential for repeat interventions. These findings support full laparoscopic ALPPS as a promising strategy for advanced colorectal liver metastases, addressing the limitations of traditional hypertrophy techniques like portal venous embolization or portal venous ligation.

INTRODUCTION

Colorectal cancer is the third most common malignant tumor worldwide, with the liver being the most frequent site of distant metastases[1]. Among these patients, 15%-25% are diagnosed with synchronous liver metastases, while another 15%-25% develop metachronous liver metastases. Due to significant improvements in 5-year overall survival, surgery remains the mainstay of curative therapy for patients with colorectal liver metastases (CRLM)[2,3]. However, owing to the widespread distribution or vascular involvement of metastases, achieving a sufficient future liver remnant (FLR) may not be possible, increasing the risk of post-hepatectomy liver failure (PHLF).

Several techniques have been developed to stimulate liver hypertrophy in patients with insufficient FLR before hepatectomy, with two-stage hepatectomy (TSH) being widely used in contemporary practice[4-6]. The first stage involves portal venous ligation (PVL) or portal venous embolization (PVE) to stimulate FLR hypertrophy, typically 4-8 weeks before the second stage of hepatectomy. This technique can increase the FLR volume by 27%-39%[6]. However, a drawback of this technique is the risk of insufficient FLR hypertrophy and tumor progression during the waiting period[4], which may result in tumor resection failure.

In 2012, Schnitzbauer et al[7] published an innovative method of liver resection called associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). A notable advantage of ALPPS is the rapid increase in FLR within a short period of approximately 2 weeks, enabling radical resection and minimizing the risk of tumor progression during the waiting period[7-13]. Additionally, the primary indication for ALPPS is CRLM, as it is considered safer for secondary than for primary liver tumors[12,14-16]. However, significant morbidity and mortality have been reported with ALPPS, making this procedure controversial[7-17]. In recent years, various modifications, including partial ALPPS, mini-ALPPS, and ablation-assisted ALPPS, have been developed to reduce the risks associated with this procedure[18]. Additionally, laparoscopic or robotic surgery offers a minimally invasive alternative to reduce the risks of ALPPS[18-23]. Nevertheless, the technical challenges of performing two complex laparoscopic liver surgeries within a short timeframe have limited the widespread adoption of the full laparoscopic ALPPS procedure. This study aimed to assess the feasibility and safety of full laparoscopic ALPPS in patients with CRLM.

MATERIALS AND METHODS

Study design

A retrospective analysis was conducted on all consecutive patients with CRLM who visited the Sixth Affiliated Hospital of Sun Yat-sen University from March 2021 to July 2024. The inclusion criteria were as follows: (1) Patients with CRLM confirmed by clinical or histological evidence; (2) Patients underwent liver surgeries, whether through open or laparoscopic approaches; and (3) Complete and detailed laboratory and clinical information. The exclusion criteria were as follows: (1) Extrahepatic metastases; (2) Patients with other primary malignant tumors; (3) Patients underwent one stage resections and/or ablations; (4) Patients underwent two-stage resections after PVE/PVL; and (5) Patients underwent open ALPPS (Figure 1).

Figure 1 The flowchart shows all consecutive patients with colorectal liver metastases who underwent liver surgery at our institution between March 2021 and July 2024. PVE: Portal venous embolization; ALPPS: Associating liver partition and portal vein ligation for staged hepatectomy.

All patients underwent a detailed clinical work-up, including computed tomography (CT) and/or magnetic resonance imaging, and their therapeutic schedules were evaluated by a multidisciplinary team prior to surgeries. The indication for ALPPS was insufficient FLR, as determined by CT measurements prior to stage 1 procedures. An insufficient FLR was defined as a remaining liver volume without tumors of less than 30% in patients without underlying liver diseases or less than 40% in patients with liver diseases, such as hepatic steatosis, cirrhosis, or liver damage after chemotherapy following the final surgery[24]. All surgeries were performed by the same surgeon (Wei-Dong Pan).

FLR calculation

The FLR volumetric analyses were performed using Vitrea 4.6 Workstation (Vital Images, Minnetonka, MN, United States). Firstly, the portal venous phases of four-phase contrast-enhanced CT scans were obtained to facilitate optimal identification of Couinaud segments and resection planes tailored to individual patient anatomy. Secondly, axial CT slices were manually traced, with interpolations of intermediate slices performed by the software. All contours, including extrapolated slices, were reviewed and corrected by two independent researchers to minimize interobserver variability. Finally, the software generated 3D reconstructions integrating vascular/ductal anatomy, with automated volume calculation. Key exclusions comprised the gallbladder and inferior vena cava (IVC), while intrahepatic structures were retained to reflect functional liver mass.

Surgical procedures

In stage 1 laparoscopic ALPPS, intraoperative ultrasound was initially performed to locate tumors in the FLR and confirm whether they involved the middle hepatic vein (MHV). If the tumors involved the MHV, the liver parenchyma was transected on the left side of the MHV in the subsequent procedure; otherwise, it was transected on the right side. Additionally, the transection was required to be at least 1 cm away from the tumor. The gallbladder was removed during stage 1. The right hepatic artery (RHA) was identified and preserved. The right portal vein was ligated without transection using double nonabsorbable sutures. Tumors in the FLR identified by ultrasound were resected and/or treated with microwave ablation according to their size and location. Subsequently, the liver parenchyma was partially transected[25] in situ to the anterior plane of the right Glisson pedicle and caudate lobe without exposing the posthepatic veins or IVC. The MHV was transected on the cephalic side when tumors were involved. Finally, the RHA was marked with loose sutures for identification during stage 2 (Figure 2). Interstage chemotherapy was not conducted. Before stage 2 of ALPPS, the volume growth and tumor progression of the FLR were assessed using CT at least 8 days after phase 1. Subsequent surgeries were performed only if the FLR hypertrophy was deemed adequate. Additional resection and/or ablation of progressive tumors in the FLR were performed if detected.

Figure 2 Main procedures in stage 1 of full laparoscopic associating liver partition and portal vein ligation for staged hepatectomy. A: Identification of the right hepatic artery (RHA) and right portal vein with the RHA preserved using a tie; B: Ligation of right portal vein by double non-absorbable sutures; C: Radical resection of tumor in future liver remnant; D: Microwave ablation of tumor in future liver remnant; E: Partial transection of liver parenchyma in situ; F: Marking of the RHA is by a loose suture for identification during stage 2.

At the start of stage 2 of laparoscopic ALPPS, adhesions between the divided liver segments were separated using gentle blunt dissection. After separating the liver hilar adhesions, the RHA and right portal vein were identified and transected. The right Glisson’s pedicle was then divided using an endostapler after transecting the lowest part of the caudate lobe and several posthepatic veins. The residual parenchyma was subsequently divided anterior to the IVC until the right hepatic vein was transected using an endostapler. Finally, complete mobilization of the right liver from the retroperitoneum and diaphragm was performed (Figure 3). The specimen was removed through a para-midline incision.

Figure 3 Main procedures in stage 2 of full laparoscopic associating liver partition and portal vein ligation for staged hepatectomy. A: Identification of the right hepatic artery (the single long loose suture) and right portal vein (the double short tight sutures); B: After transection of the right hepatic artery and right portal vein, dissection of the space posterior to the right Glisson pedicle is taken; C: Division of the right Glisson pedicle by endostapler; D: Transection of the right hepatic vein by endostapler; E and F: Completely mobilization of the right liver as the final step of stage 2. RHA: Right hepatic artery; RPV: Right portal vein.

Variables

Demographic variables, including primary colorectal cancer, liver metastases, Fong’s clinical risk score[26], and comprehensive ALPPS preoperative risk assessment (CAPRA) score[14], were recorded. Left colonic and rectal tumors were classified as left-sided primary tumors. The FLR, standardized total liver volume (sTLV), and FLR/sTLV before stages 1 and 2 were documented. sTLV was calculated based on the body surface area[27,28]. Increased velocity was defined as the increase in FLR volume divided by the number of days between the stage 1 operation and CT evaluation prior to stage 2. Intraoperative and postoperative variables were documented. Complications were assessed using the Clavien-Dindo classification[29] and quantitatively analyzed with a comprehensive complication index (CCI)[30], calculated using a web-based calculator (https://www.cci-calculator.com). PHLF was defined based on the criteria of the International Study Group of Liver Surgery[31]. Mortality was defined as death within 90 days of surgery.

Statistical analysis

Continuous variables were expressed as medians and ranges, while categorical variables were reported as counts and percentages. Given the descriptive nature of this study, no statistical tests were conducted. Statistical analyses were conducted using the SPSS Statistics version 22 software (IBM Corp., Armonk, NY, United States).

RESULTS

Participants

Complete laparoscopic ALPPS was performed in 15 patients between March 2021 and July 2024. The median age of the patients was 57 years, and 53.3% (n = 8) were male. Seven patients (46.7%) presented with left-sided primary tumors, six (40.0%) had right-sided tumors, and two (13.3%) presented with multiple anatomic localizations bilaterally. Primary tumors were resected in most patients (n = 11, 73.3%). No extrahepatic metastases were observed. Thirteen (86.7%) patients presented with synchronous liver metastases. Nine patients (60.0%) had more than five liver tumors, with a maximum of 22. The median diameter of the largest lesion was 2.8 cm on preoperative imaging. RAS mutations were detected in nine patients (60.0%). Preoperative chemotherapy, either neoadjuvant or conversion, was administered to 14 (93.3%) patients. The median CAPRA score was 2.48. Detailed information on demographic and tumor characteristics is presented in Table 1.

Table 1 Demographic and tumor characteristics, n (%).

Variable		Overall (n = 15)
Age, years		57 (37-70)
Gender	Male	8 (53.3)
	Female	7 (46.7)
BMI, kg/m2		22.0 (18.6-26.2)
ASA score	2	14 (93.3)
	3	1 (6.7)
Primary tumor
Location	Left	7 (46.7)
	Right	6 (40.0)
	Bilateral	2 (13.3)
Primary tumor resected		11 (73.3)
Liver metastases
Timing of liver metastases	Synchronous	13 (86.7)
	Metachronous	2 (13.3)
Number of tumors	1-5	6 (40.0)
	6-10	4 (26.7)
	11-20	4 (26.7)
	> 20	1 (6.7)
Bilobar disease		8 (53.3)
Max tumor size, mm		2.8 (1.4-6.5)
MHV involvement		7 (46.7)
RAS mutation		9 (60.0)
CEA before ALPPS, ng/mL		9.1 (2.0-179.2)
CRS	2	5 (33.3)
	3	8 (53.3)
	4	2 (13.3)
CAPRA score		2.48 (0.7-4.54)
Extrahepatic metastases		0 (0.0)
Chemotherapy1
Preoperative chemotherapy		14 (93.3)
Cycles of chemotherapy		8 (1-30)
Chemotherapy response	PR	7 (50.0)
	SD	3 (21.4)
	PD	4 (28.6)

¹One patient did not receive preoperative chemotherapy.

BMI: Body mass index; ASA: American Society of Anesthesiologists; MHV: Middle hepatic vein; CEA: Carcinoembryonic antigen; ALPPS: Associated liver partition and portal vein ligation for staged hepatectomy; CRS: Fong’s clinical risk score; CAPRA: Comprehensive associated liver partition and portal vein ligation for staged hepatectomy preoperative risk assessment; PR: Partial response; SD: Stable disease; PD: Progressive disease.

Operative characteristics

All patients successfully underwent full laparoscopic ALPPS without conversion to open surgery. Concomitant left-sided colorectal resection was performed in one patient (6.7%) during stage 1 ALPPS. In stage 1 ALPPS, seven patients (46.7%) underwent FLR tumor procedures, of which three (20.0%) underwent microwave ablation, and 4 (26.7%) underwent both wedge resection and microwave ablation. The median interstage interval was 17 days. Extended right hepatectomies were performed in seven patients (46.7%) during stage 2 ALPPS due to tumor involvement of the MHV. All patients underwent R0 resection. Detailed operative characteristics are presented in Table 2.

Table 2 Surgery characteristics, n (%).

Variable		Overall (n = 15)
Stage 1 of ALPPS
Associated procedures	Concomitant colorectal resection	1 (6.7)
	Ablation in FLR	3 (20.0)
	Resection and ablation in FLR	4 (26.7)
Operation time, minute		255 (170-430)
Blood loss, mL		100 (50-600)
Blood transfusion		1 (6.7)
Conversion to open		0 (0.0)
Interstage interval, days		17 (13-24)
Stage 2 of ALPPS
Type of hepatectomy	Right hepatectomy	8 (53.3)
	Extended right hepatectomy	7 (46.7)
Resection/ablation in FLR		0 (0.0)
Operation time, minute		195 (171-409)
Blood loss, mL		100 (20-1000)
Blood transfusion		2 (13.3)
Conversion to open		0 (0.0)
R0 resection		15 (100.0)

ALPPS: Associating liver partition and portal vein ligation for staged hepatectomy; FLR: Future liver remnant; R0: Microscopically radical liver resection.

Volumetric characteristics

The median FLR volume before stage 1 ALPPS was 356.0 mL, while the median FLR/sTLV ratio was 33.3%. A significant increase in the median FLR volume was observed, reaching 478.1 mL before stage 2, with the median FLR/sTLV ratio increasing to 41.5%. Furthermore, the median increase rate of FLR volume during the interstage interval was 47.0%, while the median increased velocity was 11.2 mL/day. Detailed information regarding the volumetric data is presented in Table 3. Furthermore, the FLR volume of case 4 was calculated 3 months after the stage 2 operation to evaluate FLR regeneration in the post-ALPPS period (Figure 4).

Figure 4 Regeneration of future liver remnant in the period of post-associating liver partition and portal vein ligation for staged hepatectomy. A: Future liver remnant volume before stage 2 (447.1 mL); B: Future liver remnant volume at 3 months after stage 2 (1154.6 mL).

Table 3 Volumetric characteristics.

Variable	Overall (n = 15)
FLR pre stage 1, mL	356.0 (202.6-458.3)
FLR/sTLV pre stage 1, %	33.3 (17.8-41.2)
FLR pre stage 2, mL	478.1 (380.9-642.3)
FLR/sTLV pre stage 2, %	41.5 (33.4-57.8)
Increase volume, mL	173.9 (30.7-247.8)
Increase rate, %	47.0 (7.5-97.3)
Time between stage 1 and imaging, days	10 (8-21)
Increased velocity, mL/day	11.2 (3.4-26.6)

FLR: Future liver remnant; sTLV: Standardized total liver volume.

Postoperative characteristics

Postoperative short-term outcomes are summarized in Table 4. The overall complication rate in stage 1 was 13.3% (n = 2), both of which were major complications (Clavien-Dindo ≥ 3a), presenting primarily with pleural effusion and ascites. One of these two patients developed a biliary fistula after stage 1, which was resolved in stage 2. The median CCI score in stage 1 was 0. The overall complication rate in stage 2 was 53.3% (n = 8), higher than that in stage 1. The major complication rate in stage 2 was 33.3% (n = 5), exceeding the rate in stage 1. After stage 2 ALPPS, three patients developed biliary fistula, and one had mild PHLF (International Study Group of Liver Surgery grade A). The median CCI score for stage 2 was 8.7. No reoperations or mortality occurred in either stage. The median hospital stay after stage 2 was 10 days.

Table 4 Postoperative characteristics, n (%).

Variable		Overall (n = 15)
Stage 1 of ALPPS
Complication type	Total	2 (13.3)
	Pleural effusion	2 (13.3)
	Ascites	2 (13.3)
	Biliary fistula	1 (6.7)
	Cardiac insufficiency	1 (6.7)
Complication grade	Minor (Clavien-Dindo 1-2)	1 (6.7)
	Major (Clavien-Dindo 3-5)	2 (13.3)
CCI score		0.0 (0.0-50.0)
Mortality		0 (0.0)
Stage 2 of ALPPS
Complication type	Total	8 (53.3)
	Wound infection	2 (13.3)
	Pleural effusion	3 (20.0)
	Ascites	2 (13.3)
	Biliary fistula	3 (20.0)
	PHLF (ISGLS grade A)	1 (6.7)
	Cardiac insufficiency	1 (6.7)
Complication grade	Minor (Clavien-Dindo 1-2)	4 (26.7)
	Major (Clavien-Dindo 3-5)	5 (33.3)
CCI score		8.7 (0.0-45.4)
Mortality		0 (0.0)
Hospital stay after stage 2, days		10 (5-26)

ALPPS: Associating liver partition and portal vein ligation for staged hepatectomy; CCI: Comprehensive complications index; PHLF: Post-hepatectomy liver failure; ISGLS: International Study Group of Liver Surgery.

DISCUSSION

The indications for ALPPS include liver tumors with insufficient FLR, such as hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and metastatic tumors, including CRLM[32]. A series of studies have shown CRLM to be the best indication for ALPPS[12,14-16,33,34]. In general, patients with CRLM do not have severe underlying liver diseases, such as cirrhosis or portal hypertension. Thus, stimulating a rapid increase in FLR volume may be beneficial in improving the resection rate of stage 2 operations.

CRLM is often accompanied by a high tumor burden, with widespread distribution or vascular involvement, leading to insufficient FLR volume and initial unresectability. As a more conventional strategy, PVE/PVL can increase FLR volume. However, the risks of insufficient hypertrophy and tumor progression often result in the failure of tumor resection after PVE/PVL[4]. In recent years, the LIGRO trial, the first global randomized controlled trial comparing ALPPS with TSH in patients with advanced CRLM, was completed, providing the strongest evidence for the feasibility of ALPPS[10]. The resection rate was significantly higher with ALPPS than with TSH (92% vs 57%; P < 0.0001). Another large cohort study on ALPPS from 22 centers over a 10-year period, published in 2020, reported a 96% resection rate in patients with CRLM[12]. Additionally, several studies have reported the results of minimally invasive strategies for ALPPS, with a 100% resection rate[18,23,25,35,36]. In this study, all patients successfully underwent full laparoscopic ALPPS with radical resection, achieving a high resection rate of 100%, similar to the results of previous studies.

Sufficient FLR volume is a prerequisite for the successful completion of ALPPS. Therefore, the primary reason for the high resection rates is the rapid growth of FLR volume. In this study, the median increase in FLR volume was 47.0%, which is consistent with the results of several other studies[10-12,17,18,23,35,36]. However, the factors contributing to rapid liver regeneration remain unclear. Chemotherapy with oxaliplatin and/or irinotecan is the standard systemic therapy for CRLM. However, the hepatotoxic effects of these drugs, including sinusoidal obstruction syndrome induced by oxaliplatin and steatohepatitis induced by irinotecan, have raised growing concerns. Previous studies have reported that chemotherapeutic agents are a factor in reducing liver regeneration[15,37]. However, the results of these studies are inconsistent. Recently, a cohort study using data from the International ALPPS Registry was conducted to identify factors related to FLR growth[38]. Interestingly, they reported that anthropometric characteristics, such as height, weight, FLR size, and sex, were key factors affecting FLR growth rather than chemotherapy. In this study, most patients underwent preoperative chemotherapy, with a maximum of 30 cycles administered to one patient (case 2). However, the rate of increase in this patient population was 49.6%, higher than the median rate of 47.0%. This indicates that differences in liver regeneration among individuals may be multifactorial, and further research in this area is needed.

In our experience, several key strategies have been emphasized to ensure the effectiveness of surgery and reduce intraoperative injuries. First, FLR tumors should be completely resected and/or ablated during stage 1 to ensure that the FLR achieves a no evidence of disease status after stage 1. This outcome relies on accurate localization using CT or magnetic resonance imaging before stage 1 and detailed scanning with laparoscopic intraoperative ultrasound. If FLR tumors are missed during stage 1, a repeat detail scanning should be performed during stage 2. If a condition of disappearing liver metastases occurs[39,40], early initiation of adjuvant therapy is recommended, followed by close monitoring. Second, the liver parenchyma was partially transected in stage 1 instead of being completely transected. This technique, known as “partial ALPPS”, was first developed by the Zurich’s group, though they performed it using an open approach[25]. They reported that partial ALPPS provided hypertrophic benefits comparable to those of classical ALPPS when the parenchymal transection was at least 50%. Additionally, partial ALPPS results in lower perioperative morbidity and mortality. In practice, the parenchyma was transected to the anterior plane of the right Glisson pedicle and caudate lobe, avoiding exposure of the posthepatic veins and IVC. This procedure is beneficial for maintaining the original anatomical gap between the liver and the IVC, reducing adhesions to the IVC during stage 2, which can otherwise lead to intraoperative vascular injuries. Moreover, the enhanced visualization provided by laparoscopy facilitates precise transection and helps prevent biliary injuries[35]. Furthermore, the liver should be transected in situ without mobilizing the right liver during stage 1 to minimize adhesions to the IVC and diaphragm in stage 2. Finally, a loose suture was placed on the RHA at the end of stage 1 to prevent confusion dissection and reduce the risk of hilum injury during stage 2. In conclusion, as one study stated, the main principle is to “keep the first step small, reduce liver partition, avoid liver mobilization, and postpone the second step until recovery of liver function”[35].

The high morbidity and mortality associated with ALPPS have been a subject of controversy since the first study on this complex procedure. In the first report by Schnitzbauer et al[7] in 2012, the complication and mortality rates were 68% and 12% respectively. Other authors have reported similar results[10-12,17], highlighting the security risks associated with ALPPS. However, in these studies, ALPPS was performed using an open approach, resulting in increased surgical invasiveness as well as high morbidity and mortality rates. In recent years, minimally invasive modifications and techniques have been applied to ALPPS, proving beneficial for reducing complication and mortality rates[18,23,25,35,36]. In this study, the incidence of biliary fistulas was 20% after completion of ALPPS, consistent with findings in other reports[23,35]. Patients with biliary fistulas were successfully treated with endoscopic biliary stent implantation and/or percutaneous drainage. Notably, the incidence of PHLF was 6.7%, which is lower than that reported in other studies[23]. Furthermore, morbidities in the two stages of ALPPS were quantitatively analyzed, revealing that the median CCI was 0 in stage 1 and 8.7 in stage 2. The CCI is calculated based on the complication grading by the Clavien-Dindo classification and reflects the severity of the overall complication burden on the patient, ranging from 0 (no complication) to 100 (death)[30]. The CCI results in this study demonstrate the safety of full laparoscopic ALPPS, especially in stage 1 operations. Similarly, the mortality rate in this study was 0, further demonstrating the safety of this minimally invasive approach. CAPRA predicts 90-day mortality preoperatively and offers a reliable method for selecting patients suitable for ALPPS prior to surgery[14]. It is evaluated using seven variables: Age, body surface area, primary liver tumors, comorbidities (such as severe cardiovascular disease, mild or severe diabetes, renal disease), and ALPPS types. In this study, the median CAPRA score was 2.48, indicating a probability of 90 days mortality of less than 7%[14].

CRLM has a high recurrence rate, which remains significantly high even after ALPPS with R0 resection. In this study, recurrence data were not analyzed due to inadequate follow-up time. The 1-year recurrence rate in the ALPPS group of the LIGRO trial was 53.8%[41]. Additionally, in a large 10-year cohort study on ALPPS, the hepatic recurrence rate was 60%[12]. However, they also reported that patients could achieve remarkable long-term survival after ALPPS, particularly those who underwent repeat liver surgery and/or ablation of recurrent hepatic lesions. Therefore, the FLR volume at the time of recurrence is crucial, as it is related to the feasibility of repeat surgery and/or ablation. Although many studies have focused on the increase in FLR during the interstage period of ALPPS, few reports have addressed liver regeneration after the completion of ALPPS. In this study, FLR volume was calculated for case 4 at 3 months post-ALPPS. Case 4 involved a patient with up to 22 tumors distributed bilaterally in the liver, including six on the left side and 16 on the right. Additionally, the tumors involved the MHV, resulting in an FLR volume of 352.2 mL (29.3%) prior to ALPPS. During the ALPPS period, the patient underwent local resections and ablations for the FLR in stage 1, followed by extended right hepatectomy in stage 2, preserving a liver volume of 447.1 mL (36.9%). Remarkably, the liver volume increased to 1154.6 mL at 3 months post-ALPPS, equivalent to normal liver volume (Figure 3). This phenomenon shows great potential for liver regeneration after ALPPS, offering the possibility of repeat surgery and/or ablation when tumors recur.

This study has some limitations. First, the primary limitation was the retrospective observational design without a comparative analysis. The level of evidence used in this study was low. Although selection bias was inevitable, consecutive patients were included to mitigate potential selection bias. Second, the single-center design and specific disease features resulted in a limited number of participants. Due to differences in clinical management and technical measures, the results of this study may not be fully applicable to other centers. Finally, this study lacked information on long-term survival due to inadequate follow-up time. However, some studies have demonstrated the effectiveness of ALPPS in promoting long-term survival[12,41-46].

CONCLUSION

Full laparoscopic ALPPS for CRLM is safe and feasible, with the potential for reduced morbidity and mortality. However, due to the technical complexity of this procedure, it cannot be guaranteed that each center can perform successfully and safely. It requires surgeons to be highly experienced with laparoscopic hepatectomy. Nevertheless, it must be acknowledged that this procedure can provide an opportunity for radical resection for patients with initially unresectable CRLM. Therefore, multicenter prospective comparative clinical studies should be conducted in the future.

ACKNOWLEDGEMENTS

This study is supported by National Key Clinical Discipline. We thank all the colleagues who assisted in clinical information collection.