Three-dimensional location approach with silk thread guided hepatectomy for liver tumor

Abstract

BACKGROUND

Intraoperative determination of resection margin and adequate residual liver parenchyma are the key points of hepatectomy for the treatment of liver tumors. Intraoperative ultrasound and indocyanine green fluorescence navigation are the most commonly used methods at present, but the technical barriers limit their promotion.

AIM

To evaluate the value of the three-dimensional location approach with silk thread (3D-LAST) in precise resection of liver tumors.

METHODS

From September 2020 to January 2022, 8 patients with liver tumors including hepatocellular carcinoma, intrahepatic cholangiocarcinoma, hilar cholangiocarcinoma, and gastric cancer liver metastasis were included in this study. All patients underwent 3D-LAST in precise resection of liver tumors.

RESULTS

All patients (8/8, 100%) underwent the operation successfully without any complications. During the mean follow-up of 8.7 months, all patients survived without tumor recurrence.

CONCLUSION

In conclusion, the 3D-LAST is a safe and effective new method for liver intraoperative navigation, which is practical and easy to promote.

Key Words: Hepatectomy; Laparoscopy; Liver tumor; Three dimensional; Silk thread

Core Tip: The aim of this study is to evaluate the value of the three-dimensional location approach with silk thread (3D-LAST) in precise resection of liver tumors. Eight patients with liver tumors including hepatocellular carcinoma, intrahepatic cholangiocarcinoma, hilar cholangiocarcinoma, and gastric cancer liver metastasis underwent the operation successfully without any complications. During the mean follow-up of 8.7 months, all patients survived without tumor recurrence. In conclusion, the 3D-LAST is a safe and effective new method for liver intraoperative navigation, which is practical and easy to promote.

INTRODUCTION

Hepatectomy is widely used for the treatment of liver tumors. In recent decades, the concept and practice of hepatectomy have developed from irregular, regular and anatomical to the current precise resection. Necessary assistive technologies have enabled these advances. Intraoperative ultrasound (IOUS) localization and indocyanine green (ICG) fluorescence imaging guidance are two frequently-used approaches for laparoscopic hepatectomy[1,2]. IOUS is an invaluable auxiliary means widely accepted in surgery for real-time diagnostic information to determine resection range and navigate the surgical path[3]. However, the major limitation of IOUS is the time cost during the procedure for paging the sonographers and the difficulty of deciphering two dimensional images[4]. ICG is a non-toxic water-soluble fluorophore that reveals fluorescence under the near-infrared spectrum[5]. Since liver tissue penetration is limited to 5 to 10 mm, that restricted the visualization of deeper tumors by ICG excitation, thereby interfering with its application in laparoscopic hepatectomy[6]. IOUS and ICG navigation require specific technical equipment, making implementation difficult in many centers. And these techniques will significantly increase the operation time.

Three-dimensional (3D) visualization involves extracting features and producing volumetric images based on computed tomography (CT) through a computer postprocessing technique. This tool offers a reasonable approach to the clinical decision for the potential to display the complex internal anatomy in an intuitive and stereoscopic manner[7]. In the past few decades, applying 3D simulation software for liver volume calculation, virtual simulation surgery, portal hypertension monitor, and surgical navigation has proven to be safe and effective[8].

Therefore, we propose a new method to find obvious anatomical markers and calculate the resection range according to 3D positioning before operation. During the operation, the scope of resection was delineated with silk thread, and resection was performed. This is a new practical approach, which we named as 3D location approach with silk thread (3D-LAST).

MATERIALS AND METHODS

Patients

From September 2020 to January 2022, 8 patients underwent 3D-LAST guided hepatectomy. The study was approved by the review committee of West China Hospital of Sichuan University.

The 3D-LAST protocols

(1) 3D reconstruction of the intrahepatic vessels and tumors; (2) Small virtual sticks were used to demarcate the key points of the preoperatively planned cutting edge; (3) The lines were used to connect with the key points on the surface of the virtual liver model, and the length of each line was measured; (4) Prepare silk thread with the same length and place it at the anatomical position of the liver surface; and (5) Cut the liver alone the shape of the silk thread.

During the insertion of silk, the surgeon will repeatedly compare the preoperative 3D reconstruction model. In addition, the internal anatomy of the liver was deconstructed and compared with the 3D reconstruction model to assist in adjusting the position of the silk thread during the operation.

The inclusion criteria included: No metastasis to other organs except liver lesions; liver function was Child-Pugh grade A; the remaining liver volume was sufficient; no contraindications to laparoscopic surgery, or anesthesia.

Exclusion criteria: Child-Pugh grade B or C; Model of End-stage Liver Disease score > 15; insufficient residual liver volume; the presence of distant metastasis; pregnancy or lactation; hyperthyroidism.

Anatomical hepatectomy was performed according to tumor location, size, adjacent structures, liver function, residual liver volume and other factors. The principle is a margin of at least 1 cm.

RESULTS

During the study period from September 2020 to January 2022, 5 patients with hepatocellular carcinoma, 1 patient with intrahepatic cholangiocarcinoma, 1 patient with hilar cholangiocarcinoma, and 1 patient with gastric cancer liver metastasis were assessed for liver resection. There were 5 males and 3 females. The mean age of these patients was 54.3 ± 10.2 years (34-66 years). Preoperative 3D positioning was conducted and the scope of resection was delineated with a surgical suture successfully performed in all 8 patients without complications. The treatment results of these 8 patients are shown in Table 1. The 90-day operative mortality was zero. Complications worse than Dindo-Clavien IIIa was not observed at a mean follow-up time of 8.7 months (4-16 months), there was no evidence of tumor recurrence or extrahepatic metastasis. At the time of reporting, the patients are all alive and lead normal lives.

Table 1 Clinical features of 8 patients underwent three-dimensional location approach with silk thread guided hepatectomy.

	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Patient 6	Patient 7	Patient 8
Age, years	46	57	66	55	54	58	64	34
Sex	F	F	M	F	M	M	M	M
HBV	+	-	-	+	+	-	+	+
Diagnosis	HCC	ICC	HCCA	HCC	HCC	GLM	HCC	HCC
Liver cirrhosis	Yes	Yes	Yes	Yes	Yes	No	Yes	No
Child-Pugh	A	A	A	A	A	A	A	A
Tumor size (cm)	3.2 × 2.8	4.3 × 2.7	2.6 × 1.5	1.2 × 1.0	2.3 × 2.2	2.7 × 1.6	7.1 × 6.3	4.4 × 3.6
ASA score	I	I	II	I	I	I	II	I
Operation method	Lap	Open	Lap	Lap	Lap	Lap	Open	Lap
Resected liver segment	S8	S5 + S6 + S7 + S8	S1 + S2 + S3 + S4	S6	S8	S5	S5	S2 + S3 + S4
Operative time (minute)	160	245	370	130	170	125	110	175
Blood loss (mL)	80	230	400	70	50	80	50	150

F: Female; M: Male; HBV: Hepatitis B virus; HCC: Hepatocellular carcinoma; ICC: Intrahepatic cholangiocarcinoma; HCCA: Hilar cholangiocarcinoma; GLM: Gastric cancer liver metastasis; Lap: Laparoscopy; +: Positive; -: Negative.

We take one patient as an example, 58-year-old male, who found a liver lesion 10 months after gastric cancer surgery. Enhanced CT showed that the lesion was located in the liver S5, about 1.5 cm in diameter, and considered metastatic lesions. We performed 3D-LAST guided hepatectomy on this patient (Figure 1).

Figure 1 Surgical procedure of three-dimensional location approach with silk thread guided hepatectomy. A: Three-dimensional reconstruction of the intrahepatic vessels and tumors was performed; B: The key points of the cutting edge were demarcated with small virtual sticks; C: The lines were connected with the key points on the surface of the virtual liver model; D: The length of each line was measured; E: The visceral face of the liver model; F: Prepare silk thread with the same length and place it at the anatomical position of the liver surface. The shape of the silk thread is the liver cutting line; G: The liver was resected according to the shape of the silk thread, and the middle hepatic vein was exposed in the section; H: Liver section after hepatectomy; I: After the complete resection of the liver lesion, the section shows that the tumor is completely removed with a safe margin, which is consistent with the preoperatively planned resection margin.

Other representative 3D-LAST surgical procedures are shown in Figure 2.

Figure 2 Other representative three-dimensional location approach with silk thread surgical procedures. A: The three-dimensional location approach with silk thread procedure for patient 1; B: The procedure for patient 4; C: The procedure for patient 8.

DISCUSSION

Laparoscopic liver resection (LLR) has been increasingly ubiquitous and the indications are nearly as broad as open surgery attributed to technical innovations and experience accumulation[4,9-11]. In contrast to laparotomy, LLR has prominent advantages involving reduced pain with fewer perioperative complications, and faster recovery[12,13]. Nevertheless, lack of tactile and depth perception, narrowed operating space, and limited visual field caused an inherent challenge for the expanded application of laparoscopy[14,15]. IOUS and ICG fluorescence imaging are mainly applied as real-time navigation tools to address the issue in recent years[2,4]. IOUS is performed directly on the surface of the liver without blind spots and dead corners, thus the accuracy of lesion detection and localization can be enhanced[16]. The Southampton Consensus guidelines 2018 released by the European Guidelines Meeting strongly recommend the use of IOUS in every case of laparoscopic liver surgery because it is significantly associated with intraoperative diagnosis and resection plan[3]. However, most of the IOUS is operated by sonographers. In most cases, surgeons had to call sonographers intraoperatively and pause the operation, which prolonged operative time with a strong reliance on ultrasound equipment and techniques[17]. Besides, IOUS may overestimate the disease by confusing regenerative nodules with tumors in cirrhotic livers[18]. ICG is a harmless water-soluble near-infra-red fluorescent, by uses specifically tailored scopes to detect the fluorescence, which can be of great help in the intraoperative visualization of anatomical structures identification[19]. It is nowadays widely accepted as a useful tool in numerous liver surgery fields for its high sensitivity and clear contrast in surgical navigation[20]. However, 10mm is considered to be the maximum tissue penetration range for near-infra-red light, which limited the application of ICG for lesions deep in the liver[5]. In addition, an excessive dose of ICG may cause pseudo training, and the success rate of tumor staining is associated with blood supply, liver cirrhosis, and necrosis[6]. Hence, an innovative convenient, time-saving, and accurate localization method for deep liver tumors is of great clinical value.

In this study, preoperative 3D positioning was conducted to identify obvious anatomical markers and calculate the resection range in patients with a single liver tumor. During the operation, margin lines with the corresponding length calculated by the preoperative 3D software were arranged and the edges were delineated with silk thread. This approach represents a time-saving and accurate optimal cutting plane navigation option. The operation time of IOUS and ICG-guided hepatectomy was significantly prolonged. The reported operation time was 400 (345-450) minutes[21], while the operation time of our study was only 165 (110-370) minutes. This approach not only overcome the dependence on IOUS, thus saving the operation time, and reducing the technical and condition requirements, but can be applied to a variety of navigating conditions for the liver tumors, regardless of the size and depth. Precise assessment of the number of lesions and whether there exist metastasize are especially crucial to the success of this surgical procedure. It should be pointed out that the sample size of this study is small, and further prospective studies with large samples are still needed in the future. The learning curve will also be explained. Designing a simple and widely used 3D reconstruction program is also a future goal.

CONCLUSION

Collectively, in selected patients with liver tumors, this novel resection can be used as an alternative surgical method. Given the requirement for accurate preoperative diagnosis and 3D localization, this operation is suggested to carry out in conditional hospitals. Furthermore, more cases are needed to validate and popularize our procedure.