First Series of Free Flap Reconstruction Using a Dedicated Robotic System in a Multidisciplinary Microsurgical Center

Summary:

Robotic microsurgery is a novel technology for microsurgical free flap transplantation in reconstructive surgery. Recently, the first free flap transplantation using a dedicated robotic system for microsurgery (Symani Surgical System; Medical Microinstruments) was published for a single reconstructive case. For broader future application, evaluating its potential benefits in different anatomical regions, anastomotic configurations, and clinical scenarios is necessary. In this world-wide first free flap series using this robotic system, we describe our experience with this new technology in a multidisciplinary microsurgical center. The robotic system was used for different free flaps in a range of reconstructive applications in plastic surgery, oral and maxillofacial surgery, and head and neck surgery. A total of 23 flaps were performed, with all 23 arterial and a selection of two venous anastomoses being performed with the robotic system. Time for anastomoses was significantly longer than commonly. Five of the arterial robotic anastomoses had to be redone. All but one flap survived. We could show that this new dedicated microsurgical robotic system is feasible for carrying out robot-assisted anastomoses in end-to-end, as well as end-to-side fashion under varying clinical conditions and in different microsurgical subspecialties. However, some drawbacks still need to be overcome, which are partly related to individual and institutional learning curves, to finally estimate the potential benefit for robotic free flap surgery. Multidisciplinary application of the robotic system may accelerate this process by putting together different microsurgical backgrounds, while economic burden of establishing this new technology is spread among several departments.

Takeaways

Question: Can a microsurgical robot be used for free flaps?

Findings: Successful transplantation of free flaps for various indications.

Meaning: First multidisciplinary series of robotic free flaps.

INTRODUCTION

The first application of the new dedicated microsurgical robotic platform (Symani Surgical System; Medical Microinstruments, Calci, Pisa, Italy) for a microsurgical anastomosis was described in 2022 in five cases of patients with lymphovenous anastomoses.¹ First-time transplantation of a free flap using the robotic system was presented only recently.² In that first single free flap description, a free anterolateral thigh (ALT)-flap was transplanted successfully for reconstruction of a traumatic defect of the dorsum of the foot. It was anastomosed in an end-to-end fashion to the medial tarsal artery and vein.

METHODS

To assess the potential benefits of using this dedicated microsurgical robotic system in a broader range of applications, we introduced the robotic system to the multidisciplinary microsurgical center at our tertiary medical center, comprising the three departments of plastic surgery, oral and maxillofacial surgery and ENT/head and neck surgery, in February 2023. First, all surgeons successfully completed a 4-week robotic training program ex vivo, including at least 10 successful anastomoses on artificial vessels (sized 1.0 and 2.0mm) and in the chicken leg femoral artery model using 9-0 and 10-0 sutures. The authoring six senior surgeons, comprising the directors of the three departments and their vice director, each having performed at least a few hundred microsurgical free flap transplantations over a minimum time period of 15 years, performed the arterial anastomoses in the following patients with the robotic system, which had received European conformity certification in 2019 with approval to perform microsurgery techniques in open surgery. Optical magnification was obtained by using a 4K-three-dimensional (3D) exoscope (ORBEYE; Sony Olympus Medical Solutions Inc., Tokyo, Japan). Written consent was obtained from all patients, including information about the robotic system to be used and the possibility of prolonged operation time, which in general can be an additional morbidity factor. The principles outlined in the Declaration of Helsinki have been followed. Regular multidisciplinary feedback rounds between the three departments were held to mutually learn from and discuss the different microsurgical backgrounds and current experiences using the robotic system. None of the surgeons had prior experience with robotic surgery, especially with the DaVinci surgical system. All patients scheduled for free flap transplantation in the given period of time were included. Patency of anastomosis was assessed clinically (flap recapillarization, hand-held Doppler-signaling of pedicle) and by ICG-angiography (switching to the IR-800 filter of the 3D-exoscope).

RESULTS

A total of 23 free flaps were transplanted with all arterial anastomoses being performed by the authors using the robotic system, including radial forearm flap (11), ALT-flap (seven), fibular flap (four), and anterior serrate muscle flap (one). [See table, Supplemental Digital Content 1, which displays the details of 23 reconstructive free flap cases operated on with the Symani-system (in chronological order), http://links.lww.com/GOX/A18.] In three cases, an end-to-side anastomosis was performed, whereas in the majority of cases (20), an end-to-end anastomosis was done (Figs. 1 and 2). [See figure, Supplemental Digital Content 2, which displays the typical OR-layout for Symani-robotic system in combination with 3D-exoscope in oral and maxillofacial free flaps, here during a free fibular flap for reconstruction of right mandibula (left inset = intraorally placed skin island, right inset = postoperative orthopantomogram) (pat. no. 16), http://links.lww.com/GOX/A19.] Time for arterial anastomoses differed significantly due to the varying anatomical conditions (eg, fibrotic neck after previous operations and radiotherapy, anastomosis at level lower arm after recent necrotizing fasciitis of the complete upper extremity), quality and size of recipient vessels (ranging from a young healthy patient aged 28 to a patient older than 80 years with 100 pack-years in his medical history). Average time for arterial anastomoses was 69 minutes for end-to-end anastomoses (ranging from 31 to 125 minutes) and 50 minutes for end-to-side anastomoses (ranging from 42 to 56 minutes). In two cases, the venous anastomoses were also done using the robotic system (both end-to-side to the internal jugular vein) with an anastomosis time of 68 and of 120 minutes, while all other venous anastomoses were either hand-sewn in an end-to-side fashion (except one end-to-end) with an anastomotic time of 20 to 75 minutes (mean 35 minutes) or using the ring-pin coupler device for end-to-end anastomosis (duration 7–13 minutes, mean 9 minutes). Twenty-two flaps survived with no partial or complete flap loss; one flap was lost on the first day postoperatively due to hemorrhage and subsequent comprised venous outflow from the perforator. This happened in an alcohol-dependent patient with forefoot defect who commenced mobilization on his own immediately postoperative (instead of bed rest for 5 days followed by dangling procedure). Arterial robotic anastomosis and pedicle was patent and pulsating upon hematoma revision surgery. Five of 23 arterial robotic anastomoses had to be partly redone with additional stitches (four, intraoperatively) using the robotic system or completely redone (one, on the first day after surgery, emergency revision) by hand. The underlying reason was leaking from the anastomoses (four) and questionable patency in the last case.

Fig. 1.

Free ALT-transplantation for medial elbow reconstruction after sarcoma resection (insert: end-to-side Symani-anastomosis to brachial artery) (pat. no. 1).

Fig. 2.

Free ALT-flap with short pedicle anastomosed end-to-end to the dorsalis pedis artery for reconstruction of a traumatic forefoot defect after open metatarsal fractures (insert: end-to-end Symani-anastomoses) (pat. no. 23).

DISCUSSION

Summarizing the experience of the three subspecialties of our multidisciplinary microsurgical center, the feasibility of using the robotic microsurgical platform was shown in this first free flap series, comprising different free flaps at different anatomical recipient sites for various indications. In general, all authoring microsurgeons could clearly confirm that the robotic system is sufficiently delicate for usage in microvascular procedures. In particular, the combination with the 4K-three-dimensional (3D) exoscope enabled the surgeons to teleoperate this robotic system, which stands in contrast to the so-called MUSA system,^3,4 where the conventional microinstruments (“slaves”) are hooked up directly to the robotic system mounted under an optical operation microscope with the microsurgeon working on the “masters” directly around this large mechanical system. In contrast, teleoperating with the robotic system provides optimized ergonometric and comfortable conditions for the time of anastomosis, even in particularly uncomfortable configurations (eg, reconstruction of the lateral thoracic wall/ axilla, where the microsurgeon’s hand adjacent to the patient’s trunk is usually hindered). Furthermore, the dedicated microsurgical instruments provided with this robotic system enable movements in 7 degrees of freedom, comparable to the human wrist. Conventional microinstruments cannot perform such movements. In comparison, the DaVinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, Calif.) had been pioneered by Selber et al. over a decade ago for a robotic free flap reconstruction in oropharyngeal defects.⁵ This well-established surgical system also provides complete tremor reduction, but the higher optical magnification and resolution of the 4K-three-dimensional (3D) exoscope provides superiority especially in smaller diameter vessels, for example, perforator flaps—a drawback of the DaVinci critically addressed by the author at that time.⁵ A negative factor inherent to the human hand, for example, the lack of precision and accuracy, can be overcome by the second main feature of a dedicated microsurgical robotic system: while the DaVinci Surgical System only provides motion scaling up to 3×, this microsurgical robotic system can be used with a motion scaling of up to 20×. This might additionally be a relevant didactic item for less experienced microvascular surgeons in training. Regarding the time needed for the arterial anastomoses, we experienced a significantly longer time needed as compared to conventional arterial anastomoses in each of the three departments. Possibly, this is subject to an individual learning curve and might, it is hoped, improve over time.⁶ The overly long anastomosis times in cases 3 and 5 were related to (despite prior simulation) an unforeseen need for complete repositioning of all devices during the anastomosis, which also can be attributed to the learning curve and did not reappear in the following cases. Longer time for robotic anastomoses may further be compensated in the future by less time effort for harvesting flaps with shorter (and by that smaller) pedicles (Fig. 2), because the smaller the vessel diameter, the more the robotic system will play to its strengths. Grading of the safety of the procedure is “safe” from our experience. Also, the increase of operational costs must be considered, for which a multidisciplinary cost-sharing approach as presented here might be a solution. However, regarding quantitative analysis of our results, including statistical analysis, larger series will have to be performed in the future, possibly in a multicenter study design.

There are two further shortcomings of this robotic system that were experienced by all three subspecialists. First, the lack of a touch sensation. Although eye-hand coordination and “feel-see” may be the predominant mode of work in microsurgery, haptic feedback is helpful during certain steps of anastomosis, that is, when tying the knots. Especially when pulling the sutures tight in end-to-side anastomoses, visual feedback is less reliable than haptic. In the latter case, a perfect tightness of the knot is crucial for anastomosis success. Knots which are too loose will result in a leaky anastomosis, whereas too much tension may damage the vessel or tear the suture. Second, when venous anastomosis is routinely performed in an end-to-end fashion, as in many flap procedures (eg, extremity and breast reconstruction), the venous ring-pin coupler system is standard of care in many institutions.⁷ Since the robotic system does not provide the possibility to perform a ring-pin coupler anastomosis yet, one must switch between robotic anastomosis (arterial) and manual anastomosis (venous), which is not efficient and may contribute to prolongation of time of ischemia. Since the latter is subject to a number of different influencing factors, explicit assessment of this parameter per se is not discussed here; instead, duration of anastomosis itself has been reported. Also, when performing end-to-side anastomoses to the internal jugular vein, which is standard in many microsurgical head and neck cases, the robotic system seems almost too fine for this relatively large-scale work with large diameter vessels and, therefore, probably time consuming. To obtain further data for validation of this robotic system, a valid instrument for assessing microsurgical skills and implementing appropriate microsurgical education on the robotic system might be helpful, and further studies, including multicenter settings, will be needed.^8,9

CONCLUSIONS

In conclusion, this first series of robotic microsurgical free flaps shows the feasibility of the new platform, but still larger patient cohorts will be necessary to assess whether robotics in microsurgery will be beneficial in reconstructive free flaps and in which specific indications the robotic system will be helpful. General as well as specific challenges were faced, dependent of reconstructive indications as well as specific demands for anastomosis technique (eg, arterial end-to-side anastomosis and venous coupler anastomosis) that needs to be overcome in the future. However, there are new possibilities in reconstructive microsurgery, that is, perforator free flaps with shorter (smaller diameter) pedicles and anastomosing to very small recipient vessels (perforators) or to vessels that are hard to access with conventional microinstruments arise.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.

Supplementary Material

gox-11-e5240-s001.pdf ^{(34KB, pdf)}

gox-11-e5240-s002.pdf ^{(10.8MB, pdf)}