A literature review of uniportal robotic-assisted thoracic surgery (U-RATS): current applications and future perspectives

Introduction

Robotic surgery was first introduced in the mid-1980s when the PUMA 560 robot, originally designed for industrial applications, was used to perform a brain biopsy (1). This was followed by the development of a series of surgical robot models that have evolved and improved over time. Subsequent models included PROBOT in 1989 which was used in trans-urethral surgeries (2), the Food and Drug Administration (FDA)-approved AESOP endoscopic positioning system in 1993 (3), and the ZEUS robotic surgical system which was used by Dr. Jacques Marescaux and Dr. Michel Gagner to perform the first known tele-surgery in 2001, when the surgeons performed robotic cholecystectomy from New York City on a patient located in Strasbourg, France (4). Intuitive’s da Vinci robotic surgical system gained FDA approval in 2000. Over time, it has gained popularity among general and sub-specialties surgical procedures due to its improved precision, maneuverability, and enhanced three-dimensional visualization.

The use of robotic platforms in cardiothoracic surgery started in the late 1990s and early 2000s with the use of the AESOP endoscopic positioning system and the ZEUS robotic surgical platforms to perform internal mammary artery harvesting for coronary artery bypass surgery (5,6). Subsequently, its use extended to the general thoracic field with the introduction of Intuitive’s da Vinci robotic surgical system. The first report of using a robotic platform for thoracic surgery came from Italy in 2002, when Melfi et al. shared their earliest experience with multi-port robotic-assisted thoracic surgery (RATS) in 12 patients, including five patients who underwent anatomic lobectomies (7). Three procedures were converted to mini thoracotomies, but otherwise the procedures were associated with favorable perioperative outcomes (7). Since then, multiple studies have evaluated the use of RATS and its association with a decrease in the length of hospital stay, a low overall complication rate, and an increased number of harvested lymph nodes (8-10).

More recently, uniportal RATS (U-RATS) has been introduced and has offered a promising solution to reduce acute and chronic postoperative pain associated with multiple ports insertion trauma and the torquing of robotic arms on the chest wall. A multi-institutional retrospective study compared 101 U-RATS procedures to 101 procedures performed using the traditional multi-port RATS. They found that both approaches were associated with a comparable conversion rate, number of lymph nodes harvested, and perioperative morbidity and mortality. However, the U-RATS approach was found to be associated with shorter operative time and shorter length of hospital stay compared to the multi-port RATS (11). Other potential benefits of the U-RATS approach are better cosmesis, and faster conversion to thoracotomy if needed through the same entry site use.

This article reviews the evolution, current clinical applications, techniques, and recent advances in U-RATS, with a reflection on the future perspectives of its use in the various thoracic surgical procedures. We present this article in accordance with the Narrative Review reporting checklist (available at https://vats.amegroups.com/article/view/10.21037/vats-24-6/rc).

Methods

We performed a thorough literature search using PubMed, Scopus, and Google Scholar databases. Our mesh terms included [“thoracic surgery”, and “robotic” and (“uni-portal” or “single-port”)]. Our search yielded 150 studies, which were reviewed based on title and abstract, followed by a full-text review. We only included articles that discussed the use of U-RATS in adults (18 years or older) between 2000 and January 1^st, 2024. The literature search was further updated on June 1^st, 2024. Articles not written in English were excluded. The literature review was performed independently by two authors (M.F. and M.K.A.). The selected articles were reviewed by the senior authors (N.F. and M.K.K.) before inclusion (Table 1).

Discussion

Hybrid U-RATS

The first report of using U-RATS came from China in March 2021, when Yang et al. initially described a right upper lobectomy using a single incision (12). The authors placed a 4 cm long incision in the 4^th intercostal space in the mid-axillary line. Their camera arm was placed at the upper end of the incision. As shown in Figure 1, arms 1 and 2 were intercrossed inside the chest, and the control of the arms was adjusted on the console accordingly. The positioning mark on the trocar was roughly at the same level as the patient’s skin. This avoided tissue compression and instrument collision. The procedure was performed using a hybrid approach, with dissection being performed using three robotic arms and the bedside assistant performed thoracoscopic stapling through the single port site. The patient was discharged home on the third postoperative day with no perioperative morbidity reported.

Figure 1 Hybrid U-RATS incision and trocars placement as described by Yang et al. (12). (A) Port placement for the U-RATS via da Vinci Xi. (B) Illustration of the port placement in U-RATS. U-RATS, uniportal robotic-assisted thoracic surgery.

Vincenzi et al. have subsequently reported on their hybrid technique using a single 4 cm incision in the mid-axillary line in the 6^th intercostal space to perform two anatomic lung resections (right lower lobectomy and S6 segmentectomy) (13). They again used three trocars for the procedure in addition to an assistant port through the anterior part of the incision. There were no associated intraoperative complications. The segmentectomy patient had postoperative air leak that resolved by the third postoperative day and the patient was discharged by the fifth postoperative day. While there were no complications reported for the lobectomy patient and the patient was discharged on the fourth postoperative day.

Pure U-RATS

Gonzalez-Rivas et al. have pioneered the technique for a purely U-RATS using the multi-arm da Vinci platform (14). The authors placed all 3 arm joints parallel to each other, centered in the flex position and rotated towards the anterior plane. Hence, conventional targeting was not necessary. To prevent intra-operative instrument collision, they excluded arm 1 for right sided approach, and arm 4 for the left-sided approach. They also placed the camera in the posterior-most position to allow the remaining two robotic ports to be parallel.

The authors recommend using a robotic 45 mm stapler with a curved tip for better angulation, as the 60-stapler’s internal angulation can be restricted. They made their incision in the 7^th intercoastal space between anterior and middle axillary lines for lobectomies. They adopted a hilum-first approach. As per the surgeon’s preference and the lesion’s location, the sequence can be either “Artery-Vein-Bronchus” or “Vein-Artery-Bronchus”.

In 2023, Gonzalez-Rivas et al. subsequently described the technique used for their first 30 lung U-RATS sleeve resections (11). The incision was placed in the 4th intercostal space in the anterior axillary line in the sleeve procedures. For the bronchial anastomosis, they used the camera in the 2^nd arm, Maryland in the 3^rd arm, and the needle holder in the 4^th arm (right-sided resection). They recommend placing the camera in the 3^rd arm and the needle holder on the right hand for the left-sided sleeve resections. They used a barbed suture for the bronchial anastomosis in a running fashion. Of the 30 sleeve resections reported, there was no conversion to open surgery, and one mortality secondary to ARDS was reported.

A few other reports on the use of U-RATS were recently published. Mercadante et al. have shared their experience with 24 anatomic lung resections performed with U-RATS (15). The mean operative time (including docking of the robot) was 210 (range, 120–350) minutes. This operative time decreased to 180 minutes in the last 10 cases. Other studies reported an operative time ranging from 130–216 minutes based on the procedure performed (Table 2) (18-21,23).

The patients’ postoperative peri-incisional pain was minimal, and none of the patients received opioid medications in the perioperative period. The optimal closure of the U-RATS port site is important to avoid dead space between the thoracic wall layers and around the chest tube (24).

Single-arm platform

The latest Intuitive robot model is the da Vinci SP (single port), which was released in 2018. This relatively new model was designed to overcome the challenges of a multi-arm, single-port procedure without compromising vision, precision, and control. It offers better ergonomics than a multi-port platform due to the increased flexibility of instruments, which in turn decreases the potential for instruments’ collisions. Its use is still experimental in many subspecialties, including thoracic surgery (Figure 2).

Figure 2 Da Vinci Single Port (SP) system by Intuitive. There are 3 multi-joint instruments and an articulating 3D camera (23).

The SP platform has not yet been approved by the FDA for its use in thoracic surgery (16). It has a single 2.5 cm cannula through which a 3D camera and 3 fully articulating instruments can be passed. Its use in thoracic surgery was initially reported in cadavers by Gonzalez-Rivas et al. in 2019. Subcostal and sub-xiphoid approaches were used due to the relatively large size of the 2.5 cm single port compared to the intercostal space (Figures 3,4). The authors preferred a sub-xiphoid approach with the patients in the supine position for thymectomy. A subcostal approach was used for anatomic lung resections with the patients placed in a lateral decubitus or semi-decubitus position. The bedside assistant helped with the stapling of the lung through an additional trocar. This was placed parallel to the SP robotic trocar in the same incision (25).

Figure 3 Positions for subxiphoid and subcostal approach. (A) Lateral decubitus, subxiphoid with a Gel point system. (B) right subcostal incisions and direction of gel point to be adapted to the wound protector. (C) Stapler insertion for a left upper lobectomy. From Gonzalez-Rivas et al. (25).

Figure 4 Set up for a robotic subxiphoid uniportal thymectomy. From Gonzalez-Rivas et al. (25).

For the sub-xiphoid approach, the authors used a 4 cm vertical incision just above the xiphoid process (Figures 3-5). The subcutaneous tissue was dissected, and the rectus muscles were incised near its insertions in the costal arches at the midline. The xiphoid cartilage was then excised using scissors. The retrosternal tunnel was created via blunt finger dissection to open the pleural cavity. The diaphragm was not violated during this procedure. The authors used a gel port (Gel POINT, Applied Medical Corporation, Rancho Santa Margarita, California, USA), through which the SP robotic trocar was placed, and the thoracic cavity was insufflated to a pressure of 6–8 mmHg (25).

Figure 5 Operative technique of robotic subxiphoid uniportal thymectomy. (A) Dissection of the left thymic lobe. (B) Exposure of trachea and supra-aortic trunks after complete thymectomy. From Gonzalez-Rivas et al. (25).

For the subcostal approach, the authors reported that the patient was placed in a supine position, and the incision was made one cm lateral to the xiphoid process, parallel to the subcostal margin. If needed, the xiphoid process was removed to get more space for the trocar and reduce compression on the heart. CO₂ insufflation and the use of a sternal retractor were also used to help with the exposure (25).

The first report on the use of the da Vinci SP platform for thoracic surgery procedures in clinical practice was published in 2022 (17). In that study, Park et al. reported on 17 patients who underwent an oncologic resection for a mediastinal mass using the DaVinci SP platform in Korea. Procedures were performed using subxiphoid or subcostal approaches, depending on the lesion’s location. The authors compared outcomes between SP and multi-port platforms and found no significant difference in postoperative complications and surgical mortality between the two groups.

The sub-xiphoid approach involved a vertical 3–4 cm incision made just below the xiphoid process. After the pre-peritoneal and retrosternal planes were developed, the authors used a Gel Point Mini System (Applied Medical Corporation, Rancho Santa Margarita, CA, USA) or Lap single VR (Sejong Medical, Paju, South Korea) to provide trocars access.

The subcostal approach was initiated with intrathoracic insufflation to 6–10 mmHg of CO₂ through a 5 mm assistant port in the 8^th intercostal space in the posterior axillary line. This also displaced the diaphragm inferiorly. Following this, a 3–4 cm incision was made right below the subcostal margin in the midclavicular line. A tunnel was then dissected superiorly with Metzenbaum and finger. The tunnel and the thoracic cavity connections were confirmed with the scope through the 5 mm port. All surgeries were completed without conversion to open or multi-port RATS. Figure 6 shows the setup and ports’ placement for all three approaches (17).

Figure 6 Port placement for U-RATS using Da Vinci Single Port (SP). (A) Sub-xiphoid approach, (B) subcostal, (C) intercostal. From Park et al. (17). U-RATS, uniportal robotic-assisted thoracic surgery.

Cheng et al. recently conducted a pilot trial investigating the use of the SP system in patients undergoing oncologic lung resection, including 30 lobectomies and 5 segmentectomies. Their post-operative complication rate was 17% with no mortalities reported, and only one conversion to open thoracotomy due to bleeding (23). Lee et al. have also reported their experience with the use of da Vinci SP robot for multiple thoracic procedures, including 56 pulmonary resections, 5 esophagectomies, and 41 thymectomies (22). There was only one conversion to VATS, and two procedures required placement of additional ports. There was no conversion to open thoracotomy, or mortalities reported (22). In studies by Cheng and Lee et al., the mean operative time for anatomical lung resections was 189.6 and 187.2 minutes, respectively. This is similar to the average time of 176 minutes reported by Gonzalez-Rivas et al. (25).

Limitations

The initial learning curve of U-RATS is steep, particularly with the new single-port platform, and requires good communication between the surgeon and bedside assistant to avoid robotic arms collision. In addition, the SP platform is not widely accessible and has not yet been approved to be used for thoracic procedures by the FDA in the USA. Furthermore, the initial installation expenses are expected to be substantial, placing a significant monetary burden on the healthcare facilities and insurance companies. This might make it a less desirable alternative to the widely available MRATS at the current time.

Current implications

The use of U-RATS in the various thoracic surgical procedures is still in its infancy. However, we expect that its adoption will continue to increase in the upcoming years, particularly with the introduction of the SP platform. The minimal incisional trauma and decreased peri-incisional pain associated with U-RATS are expected to provide faster patients’ recovery.

Future perspectives

The adoption rate of U-RATS is expected to significantly rise in the upcoming years. Particularly with the introduction and the expected FDA approval of the SP platform in thoracic procedures. In addition, the introduction and wider adoption of other new robotic models with separate arms might help overcome some of the challenges related to robotic arms collision noted with the current widely used models. Future studies with longer follow-ups will shed light on the oncologic outcomes associated with the U-RATS approaches.

Conclusions

There is a steep learning curve for URATS, hence, the transition can be challenging if the surgeon is not well-versed in multi-portal RATS and uniportal VATS. As per the current evidence, URATS seems a promising alternative with comparable results. However, there is a dire need for multi-center randomized studies to establish its safety and efficacy compared to the current standard of care.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://vats.amegroups.com/article/view/10.21037/vats-24-6/rc

Peer Review File: Available at https://vats.amegroups.com/article/view/10.21037/vats-24-6/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://vats.amegroups.com/article/view/10.21037/vats-24-6/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Kwoh YS, Hou J, Jonckheere EA, et al. A robot with improved absolute positioning accuracy for CT guided stereotactic brain surgery. IEEE Trans Biomed Eng 1988;35:153-60. [Crossref] [PubMed]
2. Davies BL, Hibberd RD, Ng WS, et al. The development of a surgeon robot for prostatectomies. Proc Inst Mech Eng H 1991;205:35-8. [Crossref] [PubMed]
3. Sackier JM, Wooters C, Jacobs L, et al. Voice activation of a surgical robotic assistant. Am J Surg 1997;174:406-9. [Crossref] [PubMed]
4. Morrell ALG, Morrell-Junior AC, Morrell AG, et al. The history of robotic surgery and its evolution: when illusion becomes reality. Rev Col Bras Cir 2021;48:e20202798. [Crossref] [PubMed]
5. Marescaux J, Rubino F. The ZEUS robotic system: experimental and clinical applications. Surg Clin North Am 2003;83:1305-15. vii-viii. [Crossref] [PubMed]
6. Reichenspurner H, Damiano RJ, Mack M, et al. Use of the voice-controlled and computer-assisted surgical system ZEUS for endoscopic coronary artery bypass grafting. J Thorac Cardiovasc Surg 1999;118:11-6. [Crossref] [PubMed]
7. Melfi FM, Menconi GF, Mariani AM, et al. Early experience with robotic technology for thoracoscopic surgery. Eur J Cardiothorac Surg 2002;21:864-8. [Crossref] [PubMed]
8. Motwani M, Kidambi A, Herzog BA, et al. MR imaging of cardiac tumors and masses: a review of methods and clinical applications. Radiology 2013;268:26-43. [Crossref] [PubMed]
9. Ma J, Li X, Zhao S, et al. Robot-assisted thoracic surgery versus video-assisted thoracic surgery for lung lobectomy or segmentectomy in patients with non-small cell lung cancer: a meta-analysis. BMC Cancer 2021;21:498. [Crossref] [PubMed]
10. Veronesi G, Abbas AE, Muriana P, et al. Perioperative Outcome of Robotic Approach Versus Manual Videothoracoscopic Major Resection in Patients Affected by Early Lung Cancer: Results of a Randomized Multicentric Study (ROMAN Study). Front Oncol 2021;11:726408. [Crossref] [PubMed]
11. Gonzalez-Rivas D, Bosinceanu M, Manolache V, et al. Uniportal fully robotic-assisted sleeve resections: surgical technique and initial experience of 30 cases. Ann Cardiothorac Surg 2023;12:9-22. [Crossref] [PubMed]
12. Yang Y, Song L, Huang J, et al. A uniportal right upper lobectomy by three-arm robotic-assisted thoracoscopic surgery using the da Vinci (Xi) Surgical System in the treatment of early-stage lung cancer. Transl Lung Cancer Res 2021;10:1571-5. [Crossref] [PubMed]
13. Vincenzi P, Lo Faso F, Eugeni E, et al. Uniportal robotic-assisted thoracoscopic surgery for early-stage lung cancer with the Da Vinci Xi: Initial experience of two cases. Int J Med Robot 2023;19:e2477. [Crossref] [PubMed]
14. Gonzalez-Rivas D, Bosinceanu M, Motas N, et al. Uniportal robotic-assisted thoracic surgery for lung resections. Eur J Cardiothorac Surg 2022;62:ezac410. [Crossref] [PubMed]
15. Mercadante E, Martucci N, De Luca G, et al. Early experience with uniportal robotic thoracic surgery lobectomy. Front Surg 2022;9:1005860. [Crossref] [PubMed]
16. Park SY, Han KN, Hong JI, et al. Subxiphoid approach for robotic single-site-assisted thymectomy. Eur J Cardiothorac Surg 2020;58:i34-8. [Crossref] [PubMed]
17. Park SY, Lee JH, Stein H, et al. Initial experience with and surgical outcomes of da Vinci single-port system in general thoracic surgery. J Thorac Dis 2022;14:1933-40. [Crossref] [PubMed]
18. Manolache V, Motas N, Bosinceanu ML, et al. Comparison of uniportal robotic-assisted thoracic surgery pulmonary anatomic resections with multiport robotic-assisted thoracic surgery: a multicenter study of the European experience. Ann Cardiothorac Surg 2023;12:102-9. [Crossref] [PubMed]
19. Ning Y, Chen Z, Zhang W, et al. Short-term outcomes of uniportal robotic-assisted thoracic surgery anatomic pulmonary resections: experience of Shanghai Pulmonary Hospital. Ann Cardiothorac Surg 2023;12:117-25. [Crossref] [PubMed]
20. Paradela M, Garcia-Perez A, Fernandez-Prado R, et al. Uniportal robotic versus thoracoscopic assisted surgery: a propensity score-matched analysis of the initial 100 cases. Ann Cardiothorac Surg 2023;12:23-33. [Crossref] [PubMed]
21. Stamenovic D, Schiller P, Karampinis I, et al. Uniportal robotic assisted surgery for anatomical lung resection-First German experience. Int J Med Robot 2024;20:e2580. [Crossref] [PubMed]
22. Lee JH, Park TH, Kim HK. Robotic thoracic surgery using the single-port robotic system: Initial experience with more than 100 cases. J Thorac Cardiovasc Surg 2024;S0022-5223(24)00206-X. [Epub ahead of print]. doi: 10.1016/j.jtcvs.2024.03.005.10.1016/j.jtcvs.2024.03.005
23. Cheng C, Tagkalos E, Ng CB, et al. Subcostal uniportal robotic anatomic lung resection: A pilot trial. JTCVS Tech 2024;25:160-9. [Crossref] [PubMed]
24. Gonzalez-Rivas D, Manolache V, Bosinceanu ML, et al. Uniportal pure robotic-assisted thoracic surgery-technical aspects, tips and tricks. Ann Transl Med 2023;11:362. [Crossref] [PubMed]
25. Gonzalez-Rivas D, Ismail M. Subxiphoid or subcostal uniportal robotic-assisted surgery: early experimental experience. J Thorac Dis 2019;11:231-9. [Crossref] [PubMed]