A New Approach for Robot-assisted Left Upper Lobectomy: Single-Directional via Interlobar Fissure

Abstract

Background

With the introduction of robot-assisted thoracoscopic surgery (RATS), many lung surgeries can be well exposed and completed. However, the removal of the upper lobe of the left lung still puzzles many clinicians because of its anatomical characteristics, especially in patients with large tumors and difficult flip of lung lobes, or patients with enlarged lymph nodes or portal nail lymph nodes. In this article, we introduce a new surgical approach, namely, “single-directional lobectomy via interlobar fissure (SDLIF),” for the rapid and safe removal of the left upper lung under RATS.

Materials and Methods

We retrospectively analyzed 35 patients who underwent left upper lobectomy for lung cancer using SDLIF approach under Da Vinci RATS. We counted the following indicators such as the operation time, intraoperative bleeding, number of lymph node dissection, incidence of postoperative lung air leakage, postoperative hospital stay, tumor types, pathological stages, resection completeness, and other complications.

Results

With this surgical method, all patients were successfully operated without serious complications. This procedure reduced the amount of high-value consumables used and decreased the operation time. Besides, compared with a previous study, it reduced the amount of intraoperative blood loss.

Conclusion

SDLIF is a simple, easy-to-learn, fast and safe lobectomy, which is especially suitable for patients with large tumors and difficult flip of lung lobes, or patients with enlarged lymph nodes or portal nail lymph nodes, and is a surgical technique worth promoting and spreading.

 

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Keywords

surgical approach - left upper lobectomy - robot-assisted - single-directional - interlobar fissure

Lung lobectomy has gone through the stages of traditional open thoracotomy, video-assisted thoracoscopic surgery (VATS), and robot-assisted thoracoscopic surgery (RATS). The innovation and development of these medical technologies have made lobectomy safer and more effective, thus benefiting patients worldwide.[1] [2] However, the resection of upper lobe of the left lung has always presented difficulty in the operation, as unlike the bronchial structure of the other lobes, the branches of the left pulmonary trunk and the left upper pulmonary vein surround the left upper lobe bronchus in 360 degrees, which reduces the operative space, lengthens the time of operation, and increases the risk of surgical bleeding.[3] In addition, the special anatomical structure of the left upper lobe is also the reason for the difficulty of left upper lobectomy. Therefore, surgeons hope to explore a safe, rapid, and effective surgical technique to accomplish the removal of the left upper lobe of the lung.

Single-directional lobotomy was first proposed by Professor Lunxu Liu in China. The surgical path starts from the most superficial anatomical structure and proceeds from a single direction, which is not a strictly linear path. It was performed under VATS, not RATS. It is a safe and effective pulmonary lobectomy with simple and clear procedures. It overcomes the operational difficulties of incomplete pulmonary fissure and potentially expands the indications for thoracoscopic lobectomy, which can complete the resection of each lung lobe under thoracoscope.[4] However, for an upper left lobectomy, the procedure is done under VATS; after severing the pulmonary vein, the left upper bronchus is dissected and transected, resulting in exposure of the entire left pulmonary artery, followed by ligation of each artery branch and removal of the remaining fissure tissue. Due to the different field of view of the lens, this operation sequence is feasible under VATS, but may be difficult to complete under RATS. Therefore, to adapt to and promote the development of new medical technologies assisted by robots, it is necessary to explore a new method of RATS resection of the left upper lung lobectomy.

The new concept of single-directional lobectomy via interlobar fissure (SDLIF) under RATS described in this study was performed from a different anatomical perspective than the conventional thoracoscopic approach of sequentially severing the “vein-artery-bronchus.” In the new technique introduced, we first clipped and severed the lingual segment arteries (A⁴, A⁵) and apicoposterior segment artery (A^(1+2)c) of the left lung, and then the electric coagulation hook severed the left superior lobal bronchi. By pulling the distal stump of the bronchi, the apicoposterior artery (A^(1+2)a+b), anterior artery (A³), and the left superior lobal vein were exposed, then they were clipped and severed, and the left superior lobal bronchi were sutured finally. This surgical approach is especially suitable for patients with large tumors and difficult flip of lung lobes, or patients with enlarged lymph nodes or portal nail lymph nodes, which can reduce the damage of the anterior apical trunk artery by conventional left upper lung resection and avoid massive intraoperative bleeding.

Materials and Methods

Patients

We retrospectively analyzed 35 patients who underwent left upper lobectomy for lung cancer using SDLIF approach under Da Vinci RATS between December 2019 and August 2023. The baseline characteristics of the patients are shown in the results section. This study was in line with the Helsinki Declaration, and was approved by the institutional review board of Zhongnan Hospital of Wuhan University. As this was a retrospective study, informed consent was waived by the institutional review board.

 

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Anesthesia and Surgical Position

All patients who underwent left upper lobectomy were given general anesthesia with standard double-cavity tracheal intubation. After satisfactory anesthesia, the patients were in the right decubitus position, with both upper arms extended and fixed on the hand rest, the right lower limbs extended and the left lower limbs slightly bent, and the lower limbs were fixed with a soft quilt between the lower limbs.

 

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Da Vinci Robotic Surgical Incision

The operation employed the operating system and energy system of the 4th-generation Da Vinci surgical robot, with three-arm robotic ports and an auxiliary surgical port. Surgical port settings are shown in [Fig. 1].

Fig. 1 Incision for robot-assisted thoracoscopic upper left lobectomy: single-directional lobectomy via interlobar fissure (SDLIF). Holes 1, 2, and 3 are approximately 0.8 cm incisions. Hole 1, between the posterior axillary line and the midaxillary line of the 8th intercostal space, was used for placing camera, as the observation hole. Hole 2, in the leading edge of scapula of the 8th intercostal space, was used for placing electrocoagulator arm, as the operating hole. Hole 3, in the anterior axillary line of the 6th intercostal space, was used for placing bipolar electrocoagulation hook arm, as another operating hole. Hole 4, a 2- to 4-cm incision in the 8th intercostal space, was used for placing the clamp, grasping forceps, suction device, irrigation device, suture device, and specimen extraction, as the auxiliary hole. Besides, the distance between the hole 1 and the hole 2 or hole 3 or hole 4 should be at least 8 cm, hole 4 should be on the vertical line connecting the hole 1 and the hole 3, and the hole 4 should be more than 7 cm from the vertical point.

 

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SDLIF Surgical Procedure

The left upper lobar was pulled forward to expose the interlobar plane, and the distal end of the pulmonary artery was separated along the axis of the pulmonary fissure ([Fig. 2A]). The lingual segment arteries (A⁴, A⁵) and apicoposterior segment artery (A^(1+2)c) exiting from the left upper lobe were identified and exposed in the pulmonary fissure, and then clipped and separated using a cutting stapler or biological clamp ([Fig. 2B], [C]). Subsequently, we can see the left upper lobar bronchus ([Fig. 2C]). We could not dissect the dorsal side of the bronchi as easily as we could free the lingual and apicoposterior segment arteries, as the dorsal side is attached to the branch of apicoposterior segment artery (A^(1+2)a+b), anterior segment artery (A³), and the superior pulmonary vein; forced separation of the left upper lobar bronchus is likely to lead to unexpected massive bleeding. Therefore, in this approach, we do not pursue clamping and severing of the left upper lobar bronchus, but only choose to cut the bronchus slowly from one side until the entire bronchus is severed by using the electrocoagulation hook ([Fig. 2D]). Then, by pulling the bronchial stump, we can easily expose the A^(1+2)a+b, A³, and the superior pulmonary vein. After clamping and severing the A^(1+2)a+b, the A³ will be shown more clearly ([Fig. 2H]). Next, the A³ and the superior pulmonary vein can be clamped and severed separately or together ([Fig. 2I]). Finally, the bronchial stump was closed and severed with a cutting stapler ([Fig. 2J]–[L]). After the upper lobe of the left lung was removed, hilar and mediastinal lymph nodes were dissected.

Fig. 2 Key steps in the process of operation. (A) Pulling the upper and lower lobes of the left lung, separating the interlobar fissure, then (B) pulmonary vessels were revealed via interlobar fissure, superior lingual segment artery (A⁴), inferior lingual segment artery (A⁵), and apicoposterior segment artery (A^(1+2)c). (C) The A⁴, A⁵, and A^(1+2)c were clipped and separated using a cutting stapler or biological clamp; then the left upper lung bronchus can be seen after clearing the surrounding soft tissue. (D) The left upper lobar bronchus is exposed and cut from one side until the entire bronchus is severed by using the electrocoagulation hook. (E, F) By pulling the bronchial stump and separating the surrounding soft tissue, the A^(1+2)a+b, the A³, and the left upper pulmonary vein can be easily exposed. (G, H) The A^(1+2)a+b is clamped and severed; then the A³ will be shown more clearly. (I) Clamped and severed A³ and the left upper pulmonary vein separately or together with a cutting stapler or biological clamp. (J, K) Next, the bronchial stump was closed and severed with a cutting stapler. (L) The stump of each artery, vein, and bronchus after removal of the left upper lung.Icon description: a, left upper lobe; b, left lower lobe; c, interlobar fissure; d, arch of aorta; e, superior lingual segment artery, A⁴; f, inferior lingual segment artery, A⁵; ef1, proximal end of the severed A⁴ + A⁵; ef2, distal end of the severed A⁴ + A⁵; g, apicoposterior segment artery (A^(1+2)c); g1, proximal end of the severed A^(1+2)c; g2, distal end of the severed A^(1+2)c; h, left upper lobar bronchus; h1, proximal end of the severed left upper lobar bronchus; h2, distal end of the severed left upper lobar bronchus; I, apicoposterior segment artery (A^(1+2)a+b); i1, proximal end of the severed A^(1+2)a+b; j, anterior segment artery (A³); k, left superior pulmonary vein; k1, proximal end of the severed left superior pulmonary vein; h3, proximal bronchial stump was closed and severed with a cutting stapler; h4, proximal bronchial stump to be removed.

 

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Results

Baseline Characteristics of Patients Who Underwent SDLIF Procedure

The retrospective analysis of 35 patients who underwent the described SDLIF procedure for the resection of upper lobe of the left lung included 13 females and 22 males, with a mean age of 64 years (range, 45–85 years). These patients were all confirmed to have lung cancer after surgery, with histopathological types including adenocarcinoma (n = 29), squamous cell carcinoma (n = 4), adenocarcinoma and squamous cell carcinoma (n = 1), and small cell lung cancer (n = 1), and pathological stages including stage IA1 (n = 1), IA2 (n = 2), IA3 (n = 4), IB (n = 7), IIA (n = 4), IIB (n = 8), and IIIA (n = 9).

 

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SDLIF is a Safe, Rapid Surgical Procure for Resection of Upper Lobe of the Left Lung Through RATS

This method was successfully implemented in 35 patients with lung cancer who needed to have left upper lobectomy, and the effective rate was 100%. The average operation time was 123 minutes (range, 35–215 minutes), the average amount of intraoperative bleeding was 62 mL (range, 5–200 mL), and the average number of lymph nodes collected was 10 (range, 3–31). There were eight patients with postoperative pulmonary air leakage (all healed spontaneously 3 to 9 days after surgery), and the average postoperative hospital stay was 8 days (range, 2–16 days). Other complications such as chylothorax, massive bleeding, recurrent laryngeal nerve injury, and death were not observed with this surgical approach in the study. All clinical data could be found in [Table 1].

Table 1 Clinical data of patients with left upper lung resection using SDLIF method

Characteristics	Numerical value
Age (year)	64.64 ± 9.11 (45–85)
Gender
Female	13
Male	22
Histopathological types
Adenocarcinoma	29
Squamous cell carcinoma	4
Adenocarcinoma and squamous cell carcinoma	1
Small cell lung cancer	1
Pathological stages
IA1	1
IA2	2
IA3	4
IB	7
IIA	4
IIB	8
IIIA	9
Resection completeness (%)	100
Conversion to open	0
Operation time (minutes, min)	123.00 ± 47.55 (35–215)
Intraoperative bleeding (mL)	62.00 ± 52.49 (5–200)
Number of lymph nodes collected	10.06 ± 6.24 (3–31)
Number of patients with postoperative pulmonary air leakage	8
Healing days of postoperative pulmonary air leakage (days)	5.63 ± 2.07 (3–9)
Average postoperative hospital stay (days)	8.03 ± 3.76 (2–16)
Other complications
Chylothorax	0
Massive bleeding	0
Recurrent laryngeal nerve injury	0
Wound infection	0
Death	0

Note: The numbers before and after “ ± ” represent the mean and standard deviation, respectively; the minimum and maximum values are in parentheses.

 

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Discussion

Minimally invasive surgery is the most important achievement of surgery in the 21st century, and thoracic surgery has also entered the minimally invasive era. For early and middle stage lung cancer, surgical resection of the diseased tissue is the most important treatment strategy for possible radical treatment.[5] Thoracoscopic and robot-assisted surgery technology, as representatives of minimally invasive technology, are important means of lung surgery today.[6] [7] Previous studies have confirmed that pulmonary nodules occurred mainly in the upper lobe of both lungs.[8] [9] Because of its anatomical characteristics, excision of the upper lobe of the right lung generally may be easier than that of left lung for the clinician. However, the removal of the upper lobe of the left lung often confuses many clinicians because of its anatomical location, as the left upper lung bronchus is surrounded by blood vessels, and the removal of the left upper lung often requires separation of the bronchus or arteries or veins from multiple directions. Therefore, the surgical approach proposed in this study is mainly aimed at the excision of the left upper lobe, which provides a new surgical idea for thoracic surgeons.

At present, the difficulty of thoracoscopic surgery lies in the limitation of surgical holes, which leads to the inability of instruments to move in all directions. In addition, mutual interference occurs due to the “chopstick effect.” The large angle activity of the robotic arms makes the implementation of RATS very convenient to solve the above disadvantages.[10] [11] [12] Besides, it is not convenient when the auxiliary hole of pure thoracoscopic surgery is in the fourth intercostal space, as it is easy to produce “chopstick effect” between instruments, which affects the smooth operation. However, RATS is characterized by full-hole operation with the assistance of artificial pneumothorax. The visual field direction is from the lower part of the thoracic cavity to the top of the thoracic cavity, and the anatomy of lung tissue is clear when it is pulled upward, while the SDLIF surgery method we recommend is pushed in one direction (from below the thoracic cavity to the top). Therefore, this procedure is very advantageous in RATS. We first performed the SDLIF approach in the Da Vinci robot–assisted thoracoscopic operation. However, we believe that there is no problem in successfully completing this new method using conventional thoracoscopy, and we will conduct further exploration in the future.

The traditional method is to free the branches of the left pulmonary artery or veins in the upper lobe of the lung, ligate and cut them off, and then treat the bronchus.[13] However, when pulmonary artery separation is difficult due to pulmonary tumor occupying pulmonary hilus or hilar lymph node metastasis and enlargement, forced pulmonary artery separation can easily cause vascular damage and bleeding, or even complete pulmonary resection due to persistent bleeding, and inexperienced doctors may even give up surgery due to pulmonary artery separation difficulties.

In the SDLIF method, after the left upper lung lobectomy was achieved, the lung tissue was first pulled upward to expose the interlobar fissure plane, and the arteries of A⁴, A⁵, and A^(1+2)c were freed, ligated, and cut off subsequently. Then lower wall of the left upper lobar bronchus can be easily revealed; at this time it is not necessary to fully expose the periphery of the bronchus, as we do not seek to cut and close the bronchus, but choose to slowly cut the bronchial wall from one side until the entire bronchus is severed using an electrical coagulation hook. Subsequently, the left upper lobe bronchial stump can be lifted to expose the blood vessels A^(1+2)a+b, A³, and upper pulmonary vein, which could be clamped and severed separately or together. Finally, the left upper lung bronchial stump was lifted and cut off with a straight-line cutting suture device after the left upper lobe was removed. It is worth noting that before incising the bronchus with the electrocoagulation hook, it is necessary to free as much as possible along the distal end of the bronchus to reserve the required length for the final closure of the bronchial stump, because insufficient length of the reserved stump may lead to incomplete or difficult closure of the bronchial stump, and additional sutures are needed to close the bronchial stump to avoid postoperative leakage of the bronchial stump.

In this surgical approach, after the interlobar fissure was opened and the lingual and apicoposterior segment branch arteries were cut off, the bronchus of the left upper pulmonary was exposed and only severed from one side with an electric coagulation hook instead of closing and cutting the bronchus with a linear suture device, which can avoid damage to the vessels such as anterior segment artery and another branch artery of apicoposterior segment when freeing the surrounding tissues of the bronchus in the traditional way. Besides, the apicoposterior segment artery and anterior segment artery can be exposed more easily when the bronchial stump was treated in our method. In addition, early cutting of the bronchus can also leave the hilus without the support of the hard bronchus, leaving only connective tissue, which makes it easier to deal with the branches of the pulmonary veins and arteries. This surgical approach can work well when the bronchus and blood vessels are tightly attached or when the surrounding lymph nodes are significantly enlarged, because it simplifies the separation process around the bronchus and blood vessels and avoids vascular damage due to the release of surrounding tissue. Therefore, this surgical method is especially suitable for patients with large tumors and difficult flip of lung lobes, or patients with enlarged lymph nodes or portal nail lymph nodes. Moreover, the linear suture device can be used to close the pulmonary vein and pulmonary artery branches in a cluster, reducing the use of high-value consumable devices. Compared with the data from a previous study,[14] this procedure decreased the amount of blood loss, which we believe is related to reducing the risk of bleeding of the pulmonary blood vessel caused by tissue separation around the left upper lobar bronchus. What is more, although there are no statistical data, according to our experience, our conventional surgical method of left upper lobectomy takes approximately 2.5 to 3 hours, which is significantly longer than the time spent on SDLIF (average operation time: 123 minutes). Thus, the SDLIF operation is performed in one direction, avoiding repeated flipping of lung tissue, which we believe saves operation time and reduces the possibility of iatrogenic tumor dissemination.

Of course, the procedure is performed on tumors in the left upper lung that are more than 2 cm from the initiation of the upper lobar bronchus. If the tumor is located within 2 cm of the upper lobar bronchial beginning, it is not suitable for this procedure as the principle of no tumor should be followed; then methods of suturing the bronchus manually with sutures or bronchial sleeve anastomosis can be used instead of using the cutter stapler device. It is relatively contraindicated in patients with hypoplasia of the pulmonary fissure, but is still suitable if the interlobar fissure can be successfully opened during the operation.

 

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Conclusion

The SDLIF method only travels in one direction, cuts off the bronchus earlier rather than pursuing closure, reduces unnecessary tissue separation, avoids repeated flipping of lung tissue in routine operations, decreases the risk of surgical bleeding, saves operation time, reduces the possibility of iatrogenic tumor dissemination and the surgical cost of patients. Our data prove that it is a safe, effective, simple, and easy-to-learn method for left upper lobectomy using RATS, which is especially suitable for patients with large tumors and difficult flip of lung lobes, or patients with enlarged lymph nodes or portal nail lymph nodes. Therefore, it is worthy of promoting and spreading for clinical use.

 

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Conflict of Interest

None declared.

Authors' Contributions

R.L. contributed to manuscript editing, data acquisition, and data analysis. N.C. contributed to the definition of intellectual content. X.T. contributed to data acquisition and data analysis. J.L. contributed to data acquisition and manuscript review. W.H. contributed to study concepts, study design, and manuscript review.

Data Availability Statement

The data that support the findings of this study are not publicly available due to their containing information that could compromise the privacy of research participants, but are available from the corresponding author.

Ethical Approval

This study protocol was reviewed and approved by Medical Ethics Committee, Zhongnan Hospital of Wuhan University, approval number 2022015K.

^* Contributed equally to this work and should be considered co-first authors.

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Publication History

Received: 21 December 2024

Accepted: 13 June 2025

Article published online:
14 July 2025