Robotics in Microsurgery and Supermicrosurgery

Abstract

Microsurgery has changed the ability to perform highly precise and technical surgeries through the utilization of high-powered microscopes and specialized instruments to manipulate and repair anatomical structures as small as a few millimeters. Since the first human trials of robotic-assisted microsurgery in 2006, the expansion of microsurgery to supermicrosurgery (luminal diameter less than 1 mm) has enabled successful repair of previously inaccessible structures. Surgical robotic systems can offer two distinct operative advantages: (1) minimal access surgery—by entering body cavities through ports, flap harvest can be redesigned to affect a minimally invasive approach for flaps such as the rectus abdominis muscle, the latissimus flap, and the deep inferior epigastric perforator flap; and (2) precision—by eliminating physiologic tremor, improving ergonomics, increasing accessibility to difficult spaces, and providing motion scaling, precision is significantly enhanced. Robotic-assisted microsurgery is a promising application of robotics for the plastic surgeon and has played an important role in flap harvest, head and neck reconstruction, nerve reconstruction, gender-affirming surgery, and lymphatic reconstruction—all the while minimizing surgical morbidity. This article aims to review the history, technology, and application of microsurgery and supermicrosurgery in plastic surgery.

Microsurgery is a cornerstone of reconstructive plastic surgery and has been utilized for highly technical procedures such as free tissue transfer in breast reconstruction, head and neck reconstruction, limb salvage, facial reanimation, nerve repair, and lymphatic reconstruction. Microsurgery employs a specialized operating microscope and microsurgical instruments designed to repair intricate vessels and nerves measuring less than a few millimeters in diameter. ¹ The history of microsurgery dates back to the 1960s when intraoperative magnification was introduced in vascular surgery to anastomose two ends of a canine carotid artery. ¹ The field of microsurgery further evolved under Harry J. Buncke's animal models of tissue transplantation, which subsequently led to his development of the central principles of microsurgical technique. The late 1980s saw the creation of a whole-body perforator map that outlined skin flaps based on perforator location. Perforator mapping has since become the foundation for modern day free flap reconstruction. ¹

Microsurgery has further advanced into the realm of supermicrosurgery, which involves the dissection and anastomosis of vessels and single nerve fascicles ranging from 0.3 to 0.8 mm. ¹ Supermicrosurgery uses highly delicate instruments (30- to 80-µm needle microsutures) and has made surgical intervention possible for structures that were previously inaccessible due to size. Most notably, supermicrosurgery has revolutionized treatment possibilities for patients suffering from lymphedema through lymphatic reconstruction such as lymphovenous bypass (LVB) and anastomosis. ¹

Microsurgery and supermicrosurgery rely on surgeon technical skill, specialized magnification of the operative field, and adequate instrumentation. Robotic-assisted microsurgery can mitigate challenges faced by the microsurgeon such as surgeon fatigue due to poor ergonomic positioning, physiologic tremor, and inaccessibility of space-limited structures. Advancements in robotic-assisted microsurgery address these challenges through the use of robotic telemanipulators, manned by the microsurgeon, that control an effector component of robotic arms that are equipped with microsurgical tools. Current robotic technology offers physiologic tremor elimination, improved surgeon ergonomics, motion scaling for precise surgical motions, and the ability to perform minimally invasive surgery with smaller incisional length. In plastic surgery, robotic surgery can be applied to a wide range of surgical procedures, including head and neck reconstruction, free flap harvest, nerve reconstruction, gender-affirming surgery, and lymphatic reconstruction.

History of Robotic-Assisted Microsurgery

Robotic-assisted surgery was first approved for use by the Food and Drug Administration (FDA) in 1994. In 2000, Li et al was the first to demonstrate the efficacy of a telemanipulator system, with 4 degrees of freedom, designed specifically for microsurgery (SRI International, Menlo Park, CA). ² The authors successfully performed a 1-mm femoral artery anastomoses on 10 Sprague-Dawley rats with the telemanipulator system, which resulted in equal anastomotic patency rates when compared with conventional microsurgery. ²

In 2005, Knight et al performed a larger comparison study using the Zeus Robotic Surgical System (Computer Motion, Goleta, CA). ³ The authors found similar patency rates between the Zeus robotic system and conventional microsurgery when performing 1 mm femoral artery end-to-end anastomoses in 20 Sprague-Dawley rats with 10–0 interrupted suture. However, at the time, the authors state that no discernible benefit was appreciated from the motion scaling and tremor filtration offered by the robotic system. ³ In 2005 and 2009, the da Vinci Surgical System (da Vinci SS; Intuitive Surgical Inc., Sunnyvale, CA) yielded positive results in more complex procedures such as free flap surgery and limb replantation in pig models. ^{4 5}

The first human trials of robotic-assisted microsurgery was conducted in 2006 by Boyd et al, in which the authors harvested internal mammary vessels for free flap breast reconstruction using the Aesop voice-activated robotic arm (Computer Motion Inc., Santa Barbara, CA). ⁶ The study was conducted with 22 total free flaps. While this approach allowed for long internal mammary pedicles (average length 6.7 cm) resulting in increased freedom of flap positioning, high complication rates were shown, with six patients undergoing operating room take-backs for venous congestion, and eventual total flap loss in two flaps. ⁶

One of the most well-known surgical robotic systems is the da Vinci SS (Intuitive Surgical Inc.), which was FDA approved for transoral robotic head and neck reconstruction in 2009 and has since seen remarkable progress in recent years. However, the da Vinci SS was mainly created for endoscopic surgery and therefore has limitations when performing microsurgical procedures. ^{4 7 8} Notably, the da Vinci SS visual magnification system is limited to 10 × , with poorer resolution at higher magnifications, which makes performing supermicrosurgery challenging. ⁹

The first generation of the da Vinci system (da Vinci SS) was released to market by Intuitive Surgical in 1998. ¹⁰ The second generation, the da Vinci S HD, was released in 2006 and espoused enhanced resolution and extended reach instruments for improved operative experience. The year 2010 saw the third da Vinci iteration, the da Vinci Si HD, which introduced the dual-console robot, allowing for the option of dual-surgeon procedures and active resident training. The da Vinci Xi was released in 2014 as the fourth-generation robot, which added fluorescent imaging capability and accommodations to improve operative workflow such as overhead telemanipulator setup and improved access to the patient side cart. The da Vinci X was subsequently released in 2017 as a price-conscious option for surgeons, which includes the Xi's vision cart and surgeon console with the option for further a-la-cart upgrades. ¹⁰ The most recent prototype, the da Vinci SP, was introduced in 2018 for narrow access surgery and offers three multijointed instruments and a high-definition (HD) camera through a single 2.8-cm cannula. ¹¹ The models that are available for purchase are the X, Xi, and SP.

The da Vinci system has been successfully utilized for a multitude of purposes in microsurgery. Feasibility studies published using the da Vinci SS for the elevation of free flaps include the latissimus dorsi, rectus abdominus, and peritoneal flaps for various reconstructive procedures, as well as flap inset during head and neck reconstruction. ^{7 12 13 14} Selber was the first to report use of the da Vinci SS for arterial anastomosis in oropharyngeal reconstruction in 2010. ⁷ Microanastomosis of radial forearm flaps in head and neck reconstruction and submuscular pedicle dissection during deep inferior epigastric perforator (DIEP) flap harvest have since been completed with the da Vinci SS. ^{15 16} There is currently one case described by Facca et al in which the da Vinci S, used alongside a HD endoscopic camera, was used for brachial plexus nerve repair. ¹⁷

van Mulken et al from Maastricht University Medical Center, alongside technical engineers from Eindhoven University of Technology, developed the world's first dedicated robotic platform exclusively for microsurgery and supermicrosurgery in 2020, MicroSure's MUSA (MicroSure, Eindhoven, The Netherlands). ⁹ The MUSA is designed to aid in stabilizing movements of the microsurgeon by filtering tremors and scaling down motions for increased precision. The robot is designed to be easily maneuverable within the operating room, equipped with arms holding genuine microsurgical instruments, and is compatible with standard surgical microscopes for improved magnification. ⁹ van Mulken et al conducted a 1-year human trial looking at patients undergoing lymphovenous anastomosis (LVA) for breast cancer-related lymphedema performed either with the MUSA robot ( n  = 8) or conventional microsurgery ( n  = 12). ¹⁸ Anastomosis patency was higher for the conventional microsurgery group (81.8% compared with MUSA's 66.6%). Both groups reported significant improvement in quality of life without an increase in arm circumference at 12 months. ¹⁸

The Symani Surgical System (Medical Microinstruments, S.p.A., Calci, Pisa, Italy) released a competing microsurgical robot in 2021 that utilizes miniature wristed microsurgical instruments with 7 degrees of freedom. ¹⁹ The Symani Surgical System provides motion scaling at up to 40× visual magnification, allowing for extreme precision during microsurgical and supermicrosurgical procedures. Venous and arterial anastomosis during microsurgical free flap reconstruction as well as LVA during lymphatic reconstruction have been reported using the Symani Surgical System. ^{19 20}

Microsurgical Robotic Tools

da Vinci Surgical System

The da Vinci SS has three components: surgeon console, patient cart (robotic arms), and an imaging tower ( Fig. 1 ). The surgical system is equipped with 40 different types of fully articulating robotic EndoWrist instruments. A limitation of the da Vinci system is that it lacks genuine microsurgical instrument attachments for use during surgery. ^{18 21 22 23} Brahmbhatt et al outlined how to optimize the da Vinci SS platform specifically for robotic microsurgery in plastic surgery procedures, with adaptations for current EndoWrist tools. ²²

Fig. 1.

Intuitive surgical da Vinci X surgical robot. © 2019 Intuitive Surgical Operations, Inc.

Black Diamond Micro Forceps, microbipolar forceps, Potts scissors, and curved monopolar scissors (Intuitive Surgical Inc.) are the most commonly used EndoWrist instruments in robotic microsurgery ( Table 1 ). ²² Black Diamond Micro Forceps are used for microdissection and retraction. They can further act as needle drivers for sutures as small as 11–0. Bipolar microforceps are used for fine cauterization, microdissection, retraction, and suturing with sutures as large as 6–0. Potts scissors and curved monopolar scissors are used for vessel and suture trimming. ²² While these instruments have multiple functions, they are still large in scale compared with genuine microsurgical tools and have potential to be too powerful during microsurgical operations. ⁹ In addition, the magnification of the da Vinci is still inferior to standard operating microscopes.

Table 1. Microsurgery instrument substitutes for da Vinci Xi and X.

	Microsurgery equivalent	Use	Compatibility
Black Diamond Micro Forceps	Jeweler's forceps Micro DeBakey forceps Gerald tissue forceps Microneedle holder	Fine dissection Retraction Needle driving (11–0)	Da Vinci Xi, X
Microbipolar forceps	Jeweler's forceps Micro DeBakey forceps Gerald tissue forceps Microneedle holder	Fine dissection Retraction Fine cautery Needle driving (6–0)	Da Vinci Xi, X
Potts scissors	Dissecting scissors Adventitia scissors Microscissors	Vessel trimming Suture cutting	Da Vinci Xi, X
Monopolar curved scissors	Dissecting scissors Adventitia scissors Microscissors	Vessel trimming Suture cutting	Da Vinci Xi, X

MicroSure MUSA

The MicroSure MUSA was made to be small and light weight for seamless integration within the operating room for microsurgery. The MUSA employs “master” manipulators that are controlled by the microsurgeon using forceps-like joysticks ( Fig. 2 ). ⁹ A suspension ring is attached to the operating table that can house multiple robotic “slave” arms equipped with genuine microsurgical instruments in both function and size. ⁹ The system is also compatible with standard operating microscopes, and easily accommodates the addition of a surgical microscope due to its smaller size. ^{9 18}

Fig. 2.

MicroSure MUSA microsurgical robot. © 2019 MicroSure.

Symani Surgical System (Medical Microinstruments, Italy)

Introduced in 2021, the Symani Surgical System houses two robotic arms and a surgeon console consisting of an ergonomic chair, foot-switch controller, and forceps-like joysticks ( Fig. 3 ). ²⁰ The Symani does not have an optical unit and requires the addition of an outside scope. The robotic arms contain conventional microsurgical instruments with 3-mm wrists that provide 7 degrees of freedom ( Table 2 ). Motion scaling is possible up to 7× to 20 × . The Symani has been used in Italy for lymphovenous and arterial anastomosis in 5 patients undergoing lymphatic reconstruction. While the authors state 100% anastomosis patency, they did comment that using the Symani resulted in increased operative times, on average two to three times longer due to setup and issues with having to clean the instruments multiple times for adequate use. ²⁰

Fig. 3.

The Symani Surgical System. Image courtesy of Medical Microinstruments, Inc ©.

Table 2. Functionality comparison of surgical robots.

	Optics	Console controllers	Instruments degrees of freedom/diameter	Haptic feedback	Additional features
da Vinci X, XI	3D HD	Finger loops	7 DOF 8 mm	No	Instruments reusable 10×
MUSA	N/A	Closed-joystick	7 DOF 3 mm	No	Microsurgical instruments Surgeon console at bedside Easy open conversion
Symani	N/A	Open-joystick	7 DOF 3 mm	No	Instruments need frequent intraop cleaning
Senhance	3D HD	Laparoscopic handles	3 DOF 3 mm / 5 mm	Yes	Individually mounted arms Instruments have unlimited use
REVO-I	3D HD	Finger loops	7 DOF 7.4 mm	Yes	Instruments reusable 20×
Versius	3D HD	Open-joystick	7 DOF 5 mm	Yes	Individually mounted arms

Abbreviations: 3D, three-dimensional; DOF, degrees of freedom; HD, high definition; N/A, not available.

Robotic Microsurgery Applications

Transoral Head and Neck Reconstruction

Minimally invasive resections are important alternatives for patients undergoing head and neck reconstruction, as they can provide regional tumor control while avoiding the morbidity of mandibulotomy or focused high-dose radiation. ⁷ However, minimally invasive resections in transoral head and neck reconstruction provide unique challenges for the reconstructive microsurgeon. Inset of vascularized tissue to cover complex resection defects is oftentimes difficult due to limited visibility and the space-confined nature of the anatomy. ⁷ These challenges are mitigated by robotic-assisted surgery, which has superior visualization, access, and precision in difficult-to-reach areas, specifically. ⁷

When comparing transoral robotic surgery to mandibulotomy for primary resection of oropharyngeal carcinomas with subsequent free flap reconstruction, Biron et al found that the robotic group was discharged from the hospital 5.3 days earlier. ²⁴ The robotic group also had a lower estimated overall cost of admission ($18,522.18 vs. $24,932.16). ²⁴ Similarly, Selber states that transoral robotic-assisted reconstruction is a logical solution for the challenges in contouring and suturing in a confined space with limited visibility. ⁷ The da Vinci robot was found to be especially useful for insetting flaps and primary closure in the oropharynx. ⁷

Breast Reconstruction—Internal Mammary Vessel Dissection

Robotic-assisted microsurgery has been used in internal mammary pedicle dissection; this approach does not require cartilage resection as the pedicle is brought out through the second intercostal space. ⁶ The robotic approach therefore avoids concerns regarding any resulting contour deformities from cartilage resection. This technique also results in a long internal mammary pedicle (average 6.7 cm in length, compared with the internal mammary artery's total dissectible length of 8.3 ± 3.6 cm), which is helpful when the donor free flap contains a short pedicle, such as in superior gluteal perforator artery (SGAP) flaps. ^{6 25} A longer internal mammary pedicle also provides greater freedom in flap inset and positioning. ⁶

Boyd et al conducted a 22-patient series investigating robotic-assisted free tissue transfer for breast reconstruction, including 11 transverse rectus abdominis musculocutaneous (TRAM) flaps, 6 SGAP flaps, and 4 superficial inferior epigastric artery perforator flaps. ⁶ The authors noted a high complication rate, with six take-backs for venous congestion and eventual total loss of two flaps. It was postulated that venous injuries were sustained due to too small of a tunnel created within the intercostal space for the pedicle, leading to pedicle constriction and eventual venous outflow issues. ⁶

Breast Reconstruction—Robot-Assisted Latissimus Dorsi Harvest

When the skin incision from mastectomy is minimal, such as in skin and nipple-sparing mastectomies, robotic harvest of the latissimus flap is an aesthetically favorable option. Conventional harvest of the latissimus can create a large back incision measuring up to 40 cm long, compared with the robotic technique which creates an incision between 5 and 8 cm that can be easily hidden within the axilla. ^{26 27} Robot-assisted latissimus dorsi harvest was shown to have a lower complication rate (delayed wound healing, unplanned reoperation) when compared with conventional harvest (16.7% vs. 37.5%) in patients undergoing delayed reconstruction of the irradiated breast. ¹² Robotic latissimus harvest resulted in increased operative times of 34 minutes on average. ¹²

Breast Reconstruction—Deep Inferior Epigastric Perforator Robotic Flap

The muscle-preserving DIEP flap was developed to mitigate the abdominal muscle morbidity seen with the TRAM flap. ²⁸ However, to reliably dissect the entire pedicle length of the DIEP flap, fascia is split below the arcuate line and the rectus abdominis muscle is violated to some extent. ²⁹ This muscle interference, while minimal compared with other techniques, still has the potential for subsequent hernia or bulge, especially below the arcuate line. The robotic DIEP flap harvest permits the longest possible pedicle (10–15 cm) with the smallest possible fascial incision (2–4 cm), effectively minimizing donor site morbidity. The ideal patient for robotic DIEP flap has a short intramuscular pedicle course. ²⁹ A significant reduction in postoperative pain and length of hospital stay has been associated with the robotic DIEP when compared with the conventional DIEP technique. ³⁰ Disadvantages to the robotic DIEP flap include increased operative time when the surgeon is still on the learning curve, and cost, which must be balanced against the benefits to the patient and the ability of a health system or provider to attract significant market share using new technology. ²⁸

Lymphatic Reconstruction

Lymphedema surgery is an area where robotic-assisted surgery can be uniquely helpful to plastic surgeons, as it allows access to areas that are difficult to reach with conventional surgery, provides ergonomic positioning during microsurgery, and creates additional operating angles. ^{18 31} The structures that are the subject of lymphatic anastomoses are often less than a millimeter, making them extremely challenging for the human hand. In addition, the adjunct of fluorescent imaging within the robot system can be of particular use for visualization of lymphatic channels and nodal patterns. ³²

Microsurgery, and the recent advent of supermicrosurgery, has already revolutionized treatment for both upper and lower extremity lymphedema, which had historically been managed with compression wrapping, manual massage, exercise, liposuction, and debulking surgery with limited success. ¹ In study of 1,800 patients with peripheral lymphedema who underwent LVA, 87% of patients reported subject improvement in symptoms with objective volume changes seen in 83% of patients. ³³ LVA, also referred to as LVB, is a microsurgical anastomosis between the subcutaneous lymphatic vessels, typically measuring less than 0.5 mm, into a nearby recipient venule, which directs lymphatic fluid to drain into the venous system instead of pooling in the interstitial space of the extremity. ^{31 34} LVA can be performed in an end-to-end or end-to-side fashion using 11–0 or 12–0 nylon sutures with a 50-µm needle, which requires extreme dexterity that challenges the limit of human precision. ³⁴

Vascularized lymph node transfer (VLNT) is another microsurgical technique used to treat peripheral lymphedema in which lymph nodes from a healthy lymph basin are harvested, transplanted, and microvascularly anastomosed to the lymphedematous extremity. ³⁵ Currently, theories of VLNT benefit for lymphedema treatment center on the idea that healthy lymph nodes encourage lymphangiogenesis in the recipient site and/or enhanced lymphovenous connections in a distal site—both of which lead to increased shunting of lymphatic fluid out of the interstitial space of the affected extremity. ^{33 35 36} Omental flap harvest, which is commonly used for VLNT, requires intra-abdominal dissection either through minimally invasive or open laparotomy techniques. ³² Intra-abdominal robot-assisted surgery has been shown to have superior visualization and precision when compared with endoscopy and as such minimizes risk of injury to surrounding abdominal structures. ³²

Upper Extremity

van Mulken et al performed a feasibility study for the use of robot-assisted LVA in patients suffering from upper extremity lymphadema. ¹⁸ Similar rates of anastomosis patency and postoperative outcomes such as subject quality of life improvement and reduction in compression use garments were seen between the robot-assisted and conventional LVA groups, showing that use of the robot in LVA is an acceptable alternative to conventional surgery. ¹⁸

Robotic-assisted surgery has been successfully used for VLNT during omental flap harvest in 5 lymphedema patients: 3 patients with upper extremity lymphedema, 1 patient with congenital lower extremity lymphedema, and 1 patient with bilateral lower extremity and scrotal lymphedema following oncological resection. ³² No major complications were encountered and all patients reported subjective postoperative improvement in extremity swelling and softness at 8.8-month follow-up. ³²

Lower Extremity

The da Vinci SP has been utilized for harvesting a vascularized omental flap in the treatment of a 52-year-old-man with a 3-year history of progressive lower extremity lymphedema. ³⁷ Teven et al were able to robotically harvest and extract the omental flap through a single 2.5-cm incision using the da Vinci SP system. ³⁷ The robotic-assisted harvest included right gastroepiploic pedicle dissection and lymphatic vessel identification and flap incorporation. Significant subjective improvement in lymphedema symptoms was reported at 10-week follow-up. The authors state the precise instrumentation of da Vinci SP was paramount to preserve lymphatic tissue during dissection. ³⁷

Ciudad et al used the da Vinci Si to robotically harvest a vascularized lymph node flap for the treatment of lower extremity lymphedema. ³⁸ The authors state that the three-dimensional (3D) optics, tremor elimination, and motion scaling result in extremely precise dissection that allows for preservation of the lymph nodes and fine lymphatic channels near the vascular pedicle. ³⁸

Abdominoperineal Reconstruction

Harvest of the pedicled rectus abdominis muscle for pelvic reconstruction using a minimally invasive robotic approach avoids harvest through traditional laparotomy, which disrupts the anterior rectus sheath and compromises abdominal integrity. ³⁹ As minimally invasive abdominoperineal resections, low anterior resections, and exenterations become more common, it becomes increasingly important that minimally invasive reconstructive techniques can be applied to maintain a minimally invasive approach in such extirpative, multiteam cases. Asaad et al compared robotic rectus abdominis muscle flap versus open muscle harvest in pelvic reconstruction following extirpative surgery. ⁴⁰ Lower rates of wound complications (wound dehiscence, wound infection, seroma, fistula, and mesh exposure) related to flap harvest were seen in the robotic group. ²⁵ Haverland et al showed the safety and feasibility of the intraperitoneal robotic approach for pelvic reconstruction in six medically complex patients, all of whom had successful flap reconstruction. ³⁹

Nerve Repair and Grafting

Nerve surgery is another facet of microsurgical plastic surgery that requires meticulous technical work, involving careful epineurial suturing and matching of internal fascicles. However, nerve repair typically requires lengthy incisions for adequate exposure, which is not without complication. Facca et al explored a novel technique of brachial plexus repair in a cadaver using the da Vinci S robot with a dual-endoscope HD camera. ¹⁷ Two robotic arms were introduced in the most lateral and medial cutaneous tunnels of the upper extremity, which was then carefully dissected and insufflated for exposure. Careful dissection was performed using two Black Diamond Micro Forceps and Potts scissors. Nerve grafting and epineural suturing of the C7 nerve was successfully completed using 10–0 nylon. The authors anticipate further success in robotic-assisted nerve repair with future development of appropriate forceps, graspers, welding techniques, and fibrin glue-injection techniques. Improvements in robotic magnification could prove promising for nerve supermicrosurgery, in which individual fascicles could be manipulated for extremely precise repair. ¹⁷

Gender-Affirming Surgery

Robotic-assisted peritoneal flap vaginoplasty (RPGAV) is a safe and effective technique used in gender-affirming feminizing surgery to create a neovaginal canal. Dy et al demonstrated robotic harvest of the peritoneal flap using the da Vinci Xi platform in 41 patients who had no complications related to flap harvest. ¹⁴ In addition, all patients reported successful erogenous sensation postoperatively. RPGAV does have risks associated with the intra-abdominal nature of entry when compared with perineal vaginoplasty, including bowel obstruction, intra-abdominal adhesions, peritoneal flap dehiscence and herniation, and pelvic abcess. ¹⁴ Patients most likely to benefit from RPGAV are those who are not candidates for penile inversion vaginoplasty (PIV) due to limited penile and scrotal skin, and those who have previously undergone a failed PIV that resulted in neovaginal stenosis and require canal revision. ¹⁴

Other Fields

Robotic microsurgery has been incorporated into various fields such as ophthalmology, urology, and colorectal surgery. In ophthalmology, robotic microsurgery has been employed for corneal transplant and retina surgery. ⁴¹ In urologic surgery, a robotic platform is used in microsurgical procedures such as vasectomy reversal, varicocelectomy, and denervation of the spermatic cord for various types of chronic pain. ²³ Robotic transanal minimally invasive microsurgery has been proven effective for the resection of select rectal neoplasms. ⁴²

Benefits

Robotic surgical platforms have promising capabilities to assist in the technically demanding field of microsurgery. Advantages to incorporating robotic assistance include minimal access surgery, increased precision, tremor elimination, smaller incisions, and ergonomic surgeon positioning. ^{1 9 21} Surgical robots extend the capabilities of the microsurgeon by allowing entry and precise movements in difficult-to-access spaces. ²¹ Smaller incisions permitted by a port-based approach to intracorporeal robotic-assisted surgery have been shown to reduce surgical wound morbidity, postoperative pain, and result in shorter hospital stays after surgery. ^{14 21 27} Development of robotic arms to include genuine microsurgical instruments, such as the MUSA, are promising for the field of robotic microsurgery and supermicrosurgery, as it will allow microsurgeons to further push the limits of human dexterity in the future.

Challenges

While advancements in robotic microsurgery are promising, there are still limitations and challenges that must be overcome. A lack of true microsurgical robotic instruments creates difficulty when handling the delicate tissue and equipment used in microsurgery. ²¹ Although the da Vinci's Black Diamond Micro Forceps have shown success with small vessels and nerves, the majority of the da Vinci instruments are too powerful (8-mm instruments) for fine dissection in microsurgery. Development of microsurgical robotic tools is necessary to cover the full scope and dynamic nature of microsurgical procedures, and to avoid laborious and inefficient switching from robotic to conventional surgery. Of note, Medical Microinstruments' Symani and MicroSure's MUSA are promising alternatives that overcome this issue by utilizing robotic microsurgical instruments; however, both Symani and MUSA have not yet been approved for commercial use in the United States. ^{9 19} Additionally, the da Vinci endoscopic 3D imaging system is capable of 10× magnification, but image resolution at this strength is poor compared with current surgical microscopes. ²¹

The absence of haptic feedback, in which the surgeon can feel the force that they are being applied to the tissue during surgery, has been a well-documented limitation of robot-assisted surgery. ^{8 21 23} Specifically in robotic microsurgery, lack of haptic feedback can result in inadvertent tissue or vessel laceration and suture breaks during knot tying. ^{21 43} Some have proposed that visual feedback can compensate for this deficiency, and promising new robotic platforms are in development that provide tactile feedback for the user. ⁴³

Increased operating room time has universally been displayed in robotic-assisted surgeries in many fields, including plastic surgery. ²¹ Additional time required for robot setup before the procedure, inadequate robotic training of staff, and increased time required to perform the actual surgery are all factors of increased robot-assisted surgery times. Li et al reported a total completion time of 2.6 times longer using a robotic-assisted technique compared with conventional microsurgery, which the authors attributed to difficulty with surgical tools not designed to perform microsurgery specifically. ^{2 21} Lengthened operating room times prove costly for both the patient and the hospital, as more paid staff hours and operating room fees are required. ²¹ In the senior author's experience, robotic cases like DIEPs can be performed in a time-neutral fashion compared with open if the surgeon and the team are experienced in performing the case.

Additional limitations include high costs of the robotic platform itself and robotic size within the operating room. Cost to acquire a single robot is currently in excess of $2 million, though likely to decrease with the expiry of da Vinci's patent and the introduction of competing platforms. ²¹ There are also staff training costs, alongside direct and indirect costs with operating the robot. Cost, however, is only one factor in the economics of robotic surgery. The attraction of volume and market share is lucrative for health systems. In addition, there are additional charges to insurers for robotic procedures that offset most, if not all of the variable cost associated with robotic surgeries. At the senior author's previous institution, robotic DIEPs, although more costly, had a contribution margin that was significantly higher than that of the equivalent open procedure. These are important considerations in addition to simply looking at the capital expense of the devices themselves. The size of the surgical robot can be challenging for smaller operating suites, and can impede the workflow in the operating room for surgical staff. ²¹ As with all interventions, costs of robotic-assisted surgery must be weighed alongside potential benefits for the patient, and must be accounted for in the decision-making process.

Future Directions

As the patent for the da Vinci has recently expired, this has allowed healthy competition from other surgical robot platforms that can both address gaps in the da Vinci system and drive down costs. Recent systems in development are described below.

Senhance Surgical Robotic System (TransEnterix, United States)

The Senhance surgical system consists of a remote control unit, a 3D HD monitor, an infrared eye tracking system, foot pedal, keyboard and touch pad, and up to four independent robotic arms ( Fig. 4 ). ⁴⁴ The Senhance system has the unique advantage of providing haptic feedback on the manipulation handles of the operating instruments. Most of the robotic instruments are also reduced in size, requiring 3- or 5-mm ports for placement. Unique pupil tracking technology provides optic control during the procedure. The company is also developing reusable laparoscopic tools, which would significantly bring down operational costs for hospitals. Current literature describes use of the Senhance surgical system in gynecologic and colorectal procedures, with porcine models recently conducted for urologic procedures. ⁴⁴ The Senhance system has the Conformite Europeene (CE) mark for use in Europe and the U.S. FDA approval.

Fig. 4.

Senhance Surgical Robotic System. © 2021–2023 Asensus Surgical US, Inc.

REVO-I Robotic Surgical System (Meere Company, South Korea)

The current model, MSR-5000 REVO-I, was introduced in 2015 ( Fig. 5 ). ⁴⁴ Structurally similar to da Vinci system, the REVO-I is a master-slave platform consisting of a surgeon control console, four-armed robotic operation cart, an HD vision cart, and reusable endoscopic instruments. Porcine studies show a shorter learning curve for gynecologic, urologic, and abdominal surgery. The instruments are reusable up to 20 times, which reduces costs compared with the 10 uses of da Vinci instruments. The latest version incorporates haptic feedback. The REVO-I received Korean FDA approval in 2017 and is available for human clinical work. Limitations include restricted range of motion of the needle driver compared with the da Vinci system. ⁴⁵

Fig. 5.

Senhance Microlap 3-mm instrument compared with 5-mm instrument. © 2021–2023 Asensus Surgical US, Inc.

Versius Surgical Robotic System (CMR Surgical, Inc., Cambridge, United Kingdom)

The Versius surgical system utilizes an open console with up to five robotic arms that are each a solitary unit to allow for freedom of port placement ( Fig. 6 ). ⁴⁶ Robotic instruments have 360 degrees of motion, 7 degrees of freedom, and haptic feedback. The Versius surgical system incorporates a dual-console feature which allows two surgeons to operate in two different anatomic fields at the same time, independently. ⁴⁵ The dual-console feature is a unique addition that could greatly benefit residency trainees, as it would allow active assistance and supervised practice during robotics cases with faculty. This collaborative operating approach could also prove useful in microsurgery, where oftentimes both flap harvest and recipient site preparation are performed simultaneously between two surgeons. Instrument trocars are reduced in size at 5 mm. Clinical safety and efficacy studies were successfully performed in both gynecologic and abdominal surgeries. ⁴⁵

Fig. 6.

Versius Surgical Robotic System. © 2023 CMR Surgical Ltd.

Conclusion

Robotic-assisted microsurgery is a promising tool to add to the repertoire of the plastic surgeon. Robotic-assisted microsurgery helps minimize surgical morbidity and can be applied to the harvest and inset of free flaps as well as microsurgical anastomosis of vessels, nerves, and lymphatic channels. As microsurgery continues to expand into the realm of super- and nanomicrosurgery, robotic technology could open the door for surgical procedures that were once believed impossible.

Funding Statement

Funding None.