Clinical feasibility of laparoscopic left lateral segment liver resection with magnetic anchor technique: The first clinical study from China

Abstract

BACKGROUND

Magnetic anchor technique (MAT) has been applied in laparoscopic cholecystectomy and laparoscopic appendectomy, but has not been reported in laparoscopic partial hepatectomy.

AIM

To evaluate the feasibility of the MAT in laparoscopic left lateral segment liver resection.

METHODS

Retrospective analysis was conducted on the clinical data of eight patients who underwent laparoscopic left lateral segment liver resection assisted by MAT in our department from July 2020 to November 2021. The Y-Z magnetic anchor devices (Y-Z MADs) was independently designed and developed by the author of this paper, which consists of the anchor magnet and magnetic grasping apparatus. Surgical time, intraoperative blood loss, intraoperative accidents, operator experience, postoperative incision pain score, postoperative complications, and other indicators were evaluated and analyzed.

RESULTS

All eight patients underwent a MAT-assisted laparoscopic left lateral segment liver resection, including three patients undertaking conventional 5-port and five patients having a transumbilical single-port operation. The mean operation time was 138 ± 34.32 min (range 95-185 min) and the mean intraoperative blood loss was 123 ± 88.60 mL (range 20-300 mL). No adverse events occurred during the operation. The Y-Z MADs showed good workability and maneuverability in both tissue and organ exposure. In particular, the operators did not experience either a “chopstick” or “sword-fight” effect in the single-port laparoscopic operation.

CONCLUSION

The results show that the MAT is safe and feasible for laparoscopic left lateral segment liver resection, especially, exhibits its unique abettance for transumbilical single-port laparoscopic left lateral segment liver resection.

Key Words: Magnetosurgery/magnetic surgery, Magnetic anchor technique, Laparoscopic hepatectomy, Transumbilical single-port laparoscopy, Magnet

Core Tip: Magnetic anchor technique (MAT) can be used to assist in exposing tissues or organs during laparoscopic surgery, thereby effectively reducing the number of trocars and eliminating interference between laparoscopic instruments. This study retrospectively analyzed eight patients who underwent laparoscopic left lateral lobectomy using Y-Z magnetic anchor devices. The results showed that MAT is safe and feasible for transumbilical single-port laparoscopic left lateral hepatectomy.

INTRODUCTION

Since the laparoscopic resection of benign liver tumors was first reported in 1991[1], laparoscopic liver resection has progressively developed and its safety and feasibility have gradually increased[2,3]. Laparoscopic hepatectomy has become a common operation in hepatobiliary surgery with the advantages being less trauma and faster recovery[4]. The unique anatomical structure of the left lateral hepatic lobe makes laparoscopic left lateral segment liver resection an earlier and more widely used laparoscopic hepatectomy. As a result, it has thus been considered to be the first “gold standard” laparoscopic procedure, replacing open left lateral lobectomy for liver resection[5-7].

Transumbilical single-port laparoscopic left lateral lobectomy has been reported[8-10]. However, the “chopstick” and “sword-fight” effects caused by the single-port not only confines the intraoperative maneuverability of the laparoscope instruments[11], but also hinders the interplay of traction and counter-traction between the instruments for effectively stretching and exposing the tissues and organs in the single-port laparoscopic operation. Taking this into account, in addition to the demand for laparoscopic surgeons to continuously improve their single-port operating skills, there is a need for developing better instruments for single-port laparoscopic operations.

The magnetic anchor technique (MAT) uses magnetic devices to perform non-contact spatial anchoring between the anchor magnet and the target magnet[12], which can be used to assist tissue or organ exposure in laparoscopic surgery[13], thereby feasibly reducing the number of inserted trocars, and eliminating the reciprocal interferences between laparoscopic instruments. Tentatively magnetic anchor devices have been used in laparoscopic cholecystectomy with port-reduction[14-16], but there are no reports on the use of magnetic anchor devices in laparoscopic hepatectomy. Herein we report our experiences on the clinical feasibility of a Y-Z magnetic anchor device (Y-Z MADs) in a laparoscopic left lateral hepatectomy.

MATERIALS AND METHODS

Y-Z MADs

The Y-Z MADs was designed by the authors (Yan XP and Zhang MM) and consists of an anchor magnet and a magnetic grasping apparatus. The auxiliary operation instrument is a titanium alloy tissue grasping forceps. The anchor magnet is a cylindrical magnet with a diameter of 60 mm, a height of 160 mm, and a mass of 2242 g (Figure 1A), made of N50 sintered-type neodymium-iron-boron magnetized with axial saturation with 7500 gausses of the magnetic induction intensity on the surface of the magnet, and housed with a 10 mm thick plastic cover. The magnetic grasping apparatus that possesses a tissue clip connecting a target magnet with a silk thread has a total length of 55 mm and a mass of 18.5 g, and can smoothly pass through a 12 mm laparoscopic port (Figure 1B). Experimentally, the magnetic force curve showed that the maximum magnetic force can reach as high as 59.17 N when the anchor magnet and the target magnet are attracted together at zero distance (Figure 2).

Figure 1 Y-Z magnetic anchor devices. A: Anchor magnet and the titanium alloy tissue grasping forceps; B: Magnetic grasping apparatus.

Figure 2 Magnetism test of the Y-Z magnetic anchor devices. A: Magnetism test equipment; B: The anchor magnet and target magnet in the test state; C: The magnetic force-displacement curve of the anchor and target magnet. AM: Anchor magnet; TM: Target magnet.

Ethical statement

This single-center, retrospective clinical study was conducted at an academic medical center and approved by its ethics committee (No. 2018-W18). We conducted this study in accordance with the Declaration of Helsinki, and all methods were performed in accordance with the relevant guidelines and regulations. All patients or their authorized legal representatives signed the informed consent form for the use of MAT in their operations.

The inclusion and exclusion criteria

The included patients conformed to the following criteria: (1) A preoperative computerized tomography scan or magnetic resonance imaging of the upper abdomen gave a clear diagnosis, and if the malignant lesion was unveiled, it must be confined to the left lateral lobe of the liver; (2) Informed consent had been signed by the patient or their family members; and (3) Body mass index (BMI) should be no more than 30 kg/m². In addition, the patients were excluded from this study if they: (1) Presented with a history of upper abdominal surgery or severe intra-abdominal adhesions; (2) Were found to have any metastatic lesion, either intrahepatic or extrahepatic; (3) Had a cardiac pacemaker implanted; (4) Had a BMI over 30 kg/m²; (5) Suffered severe cardiopulmonary diseases and were not able to tolerate general anesthesia during surgery and/or patients with pneumoperitoneum; and (6) Were considered inappropriate by the investigator for other reasons.

The clinical data of eight patients who underwent magnetic anchor-assisted laparoscopic left lateral hepatic lobectomy were retrospectively analyzed. Demographically, two patients were female and six were male in this study, aged between 23 and 75 years, with a median age of 49.5 years. Their BMI ranged from 19.26 to 26.30 kg/m², with a median of 23.19 kg/m². Diagnostically, three of the patients had hepatic hemangioma, one had primary liver cancer, two had primary liver cancer complicated with gallbladder stones, one had liver metastases, and one had focal hepatic steatosis.

Surgical procedure

Among the eight patients in this study, the first three underwent 5-port laparoscopic operations with the purpose of developing the stepwise procedure for the MAT-assisted laparoscopic left lateral hepatic lobectomy. Afterwards, based upon the practical experience gained from the first three patients, we performed transumbilical single-port laparoscopic left lateral hepatic lobectomy on the remaining five patients.

The MAT-assisted 5-port left lateral hepatic lobectomy was started once general anesthesia took effect. After the patients were placed in a lithotomy position with slight reverse trendelenburg tilting to left, five trocars were placed in the abdominal wall as shown in Figure 3A, and subsequently, the pneumoperitoneum was established with the pressure maintained at the level of 12 mmHg. The magnetic grasping forceps were delivered into the peritoneal cavity through the 12 mm port using the titanium alloy tissue grasping forceps, and then clamped on the edge of the left lateral lobe of the liver. The anchor magnet was then placed on the abdominal wall to attract the target magnet so that the liver could be pulled up following the movement of the anchor magnet (Figure 3B). Once this was completed, the coronary ligament and the left deltoid ligament were disconnected from their attachment to peritoneal wall, and the liver capsule and superficial liver parenchyma were opened with an ultrasonic scalpel by following the marking line made with an electric hook. Along the resection, titanium clips were used to close the smaller vascular branches before cutting, while the larger branches were clipped with vascular clips and freed until they were close to the hepatic pedicle of the left lateral lobe of the liver. At the same time, the left hepatic vein and the left lateral hepatic lobe of the liver were sequentially transected with two linear cutting and closure devices (Figure 3C). For the patient with cholecystolithiasis and chronic cholecystitis, his gallbladder was successfully removed by conventional methods during the operation. Before concluding the operation, the anchoring magnet was taken away from the abdominal wall, the magnetic grasping apparatus was retrieved with a titanium alloy grasping forceps, and the specimens were placed in a specimen bag and taken out through the extended incision below the umbilicus (Figure 3D). The abdominal cavity drainage tube was placed in the liver section, which was drawn out from the abdominal wall and fixed.

Figure 3 Magnetic anchor-assisted 5-port left lateral hepatic lobectomy operation procedure (patient 2). A: The layout of the abdominal wall port and the position of the anchor magnet; B: The magnetic anchoring device pulling the left lateral lobe of the liver to reveal the tumor lesion and the hepatogastric ligament; C: The left lateral lobe of the liver is shown under the magnetic anchoring device, which is transected at the hepatic pedicle of the left lateral lobe of the liver with a linear cutting and closure device; D: The left lateral hepatic lobe and gallbladder specimens that are resected. AM: Anchor magnet.

For the MAT-assisted transumbilical single-port laparoscopic left lateral hepatic lobectomy, after a 4 cm arcuate incision was first made under the umbilicus as shown in Figure 4A, a single-port (Hangzhou Kangji Medical Instrument Co., Ltd.) was inserted, and the pneumoperitoneum was established with a pressure of 12 mmHg. After laparoscopically surveying the abdominal cavity, the magnetic grasping apparatus was introduced into the cavity through the single-port to clamp the edge of the left lateral lobe of the liver. At the same time, the anchoring magnet was placed outside the right upper abdominal wall of the patient to attract the target magnet to the magnetic grasping apparatus. After maneuvering the pulling direction and strength to create ample exposure to the operating field, the falciform ligament, left coronary ligament, and left deltoid ligament were sacrificed by ultrasonic scalpel, and the “two-step two-nail” technique was adopted to sequentially remove segment II and part of segment III of the left lateral lobe of the liver (Figure 4B and C). Following this, the anchoring magnet was removed from the abdominal wall, both the magnetic grasping apparatus and the bagged resected liver were taken out through the single-port, and the indwelling abdominal drainage tube in the liver section was led out of the body from the umbilical incision and fixed (Figure 4D). The operation was then complete. The surgical procedure of patient 8 is shown in the Video.

Figure 4 Magnetic anchoring-assisted transumbilical single-port laparoscopic left lateral hepatic lobectomy process (patient 5). A: The subumbilical single-port and the anchor magnet; B: The Y-Z magnetic anchor devices pulling the left lateral lobe of the liver to reveal the liver section; C: The linear cutting and closure device was used to cut off segment II and part of segment III of the left lateral lobe of the liver; D: The resected segment II and part of segment III of the left lateral lobe of the liver. AM: Anchor magnet.

Statistical analysis

Study parameter indicators included operating time, intraoperative blood loss, damage to the surrounding organ, failure of the magnetic anchoring device, the operating experience of the operator and assistants, postoperative incision pain score, postoperative hospital stay, perioperative complications, and other indicators. SPSS 20.0 software was used for statistical analysis. The measurement data of normal distribution were expressed as (mean ± SD), while the measurement data of skewed distribution were expressed as a median.

RESULTS

MAT-assisted laparoscopic left lateral hepatic lobectomy was successfully performed on all eight patients without the conversion to an open procedure or use of the Pringle maneuver. Five patients had successful single-port operations without the addition of any trocars in the abdominal wall. Intraoperatively, the Y-Z MADs made the surgical field exposed well so that none of the surrounding organs were accidentally damaged. Statistically, the mean operating time was 138 ± 34.32 min (range 95-185 min), and the mean intraoperative blood loss was 123 ± 88.60 mL (range 20-300 mL). Postoperatively, all patients had no bile leakage or bleeding after the operation, the abdominal drainage tube was removed 0-5 d after the operation, incisional pain scores were maintained at the level of less than 3, and hospital stay was between 2-6 d. In the follow-up examinations one month after the operation, all patients presented with a good prognosis. Moreover, in the three transumbilical single-port laparoscopic left lateral lobectomies, both the operator and the scope driver had a positive operating experience with no complaint of either the “chopstick” or “sword fight” effect between the instruments. All the perioperative parameters are shown in Table 1.

Table 1 Clinical data of magnetic anchor-assisted laparoscopic left lateral hepatic lobectomy.

Patient no.	Gender	Age (yr)	BMI (kg/m2)	Diagnosis	Child-Pugh scoring	Extent of resection	Tumor size	Number of ports	Operative (min)	Bleeding volume (mL)	Pain score1	Drainage tube retention time (d)	Postoperative hospital stay (d)
1	Male	61	26.30	Primary liver cancer	5	Left lateral lobe	45 mm × 45 mm × 32 mm	5	100	100	2/3/3	5	5
2	Male	51	21.67	Primary liver cancer, gallstone	5	Left lateral lobe + gallbladder	40 mm × 35 mm × 40 mm	5	170	110	3/3/3	4	5
3	Female	42	19.26	Hepatic hemangioma	6	S2 + partial S3	82 mm × 60 mm × 45 mm	5	110	100	3/3/2	4	6
4	Female	23	21.88	Focal hepatic steatosis	5	Left lateral lobe	25 mm × 23 mm × 20 mm	1	185	300	1/1/2	0	4
5	Male	48	24.91	Hepatic hemangioma	5	Left lateral lobe	62 mm × 50 mm × 43 mm	1	150	100	2/2/2	2	5
6	Male	75	24.24	Liver metastases	5	S2 + partial S3	55 mm × 45 mm × 60 mm	1	165	200	2/2/2	5	6
7	Male	37	22.65	Hepatic hemangioma	5	Left lateral lobe	72 mm × 55 mm × 45 mm	1	130	50	1/2/2	3	3
8	Male	57	23.72	Primary liver cancer, gallstone	5	S2 + gallbladder	25 mm × 20 mm × 13 mm	1	95	20	2/1/1	0	2

¹Using the Wong-Banker facial expression pain score, the table lists the pain scores of the patients’ surgical incisions on the 1^st, 2^nd, and 3^rd d after the operation.

BMI: Body mass index.

DISCUSSION

Single-port laparoscopic surgery further reduces abdominal wall trauma and is of great significance for the development of minimally invasive surgery. However, both the “chopstick” and “sword-fight” effects in the single port laparoscopic operations seriously impair the operating experience of the surgeons and their assistants through increasing the difficulty of surgical field exposure and making the maneuverability of the laparoscopic instruments more awkward. Despite several methods being applied in practice, such as a reduction in the number of instruments or suture suspension[17], none of the modus operandi can workably expose the surgical field well. As a special traction technique, the MAT has been tentatively used in port-reduced laparoscopic surgery and endoscopic submucosal dissection. Mechanically, the magnetic anchor device can generate non-contact attraction outside the body cavity on the target magnet in the cavity, thus being able to create a traction and counter traction effect, which may pull the tissue or organs away from the surgical field and improve the visibility of the anatomical structures. The MAT has been piloted to assist thoracoscopic lung wedge resection and esophagectomy[18,19], laparoscopic cholecystectomy[14,15], and laparoscopic hysterectomy[20]. Moreover, in the endoscopic operation technique, the MAT has been shown to assist the lesion traction in endoscopic submucosal dissection[21,22].

We independently designed and developed Y-Z MADs suitable for laparoscopic surgery. The device has been clinically used for port-reducing and single-port laparoscopic cholecystectomy and has achieved promising clinical results in our clinics. In this study, the Y-Z MAD was used for the first time in a laparoscopic left lateral hepatic lobectomy. Since laparoscopic liver resection is more complex than laparoscopic cholecystectomy, the key aspects should be emphasized during the operation. Firstly, compared with the use of the MAT in laparoscopic cholecystectomy, transumbilical single-port laparoscopic left lateral hepatic lobectomy required a much stronger traction force to be applied to the left lateral lobe of the liver than the gallbladder. If the abdominal wall is too thick, it may mitigate the magnetic field for achieving a firm grasp of the liver, so we only performed the MAT-assisted single port liver procedure on the patients with a BMI less than 30 kg/m². Secondly, the assistant (magnetic palmist) should know how to dexterously move the anchor magnet to change the grasping direction or extent of tissue or organ exposure to accommodate the needs of the surgeon during the operation. One important aspect to avoid is the large-scale rapid movement of the target magnet to eliminate the “de-anchoring”, which can interrupt the continuity of the surgical operation. In addition, when the magnetic palmist cannot obtain satisfactory exposure by adjusting the anchor magnet, the surgeon should internally adjust the position of the grasping forceps in time in order to obtain a better traction effect. Thirdly, the MAT-assisted transumbilical single-port laparoscopic left lateral hepatic lobectomy is an innovative operating method, so both the surgeon and the assistant should not only master the knowledge of the MAT but also train themselves to improve operating finesses in order to perform the MAT-assisted single-port procedure(s).

CONCLUSION

This study preliminarily shows that the MAT can assist multiple-port as well as single-port laparoscopic left lateral hepatic lobectomy. The MAT indeed undermined the single-port-related “chopstick” and “sword-fight” effects so that it improved the surgeon’s operating experience and contributed to abating postoperative pain at incisional sites. Of course, this study is a retrospective study with only eight cases, which is a limitation of this study. In future, we will conduct a prospective randomized controlled trial to continuously evaluate the safety and feasibility of the use of the MAT in transumbilical single port left lateral hepatectomy. In summary, this study showed that the MAT is safe and feasible for transumbilical single-port laparoscopic left lateral segment liver resection.