Some surgeons prefer anterolateral thigh and latissimus dorsi flaps over radial forearm flap for soft tissue reconstruction in head and neck area because donor site repair can be done by primary closure . Also, it is thought that younger patients who are sensitive to aesthetic outcome will prefer anterolateral thigh flap because the scar can be hidden . In our study, however, some patients who were sensitive to cosmetic results preferred robot-assisted radial forearm flap to anterolateral thigh flap, presumably because the scar of anterolateral thigh flap is much longer than that of radial forearm flap and due to thigh asymmetry caused by large volumetric defect after anterolateral thigh flap. This may also account for the significantly younger mean age of the robot-assisted radial forearm flap group.
Many studies reported methods of repairing donor site after radial forearm flap. Usually split thickness and full thickness skin grafts are used for repair [14, 15]. Recently, local flap or allogenic dermal matrix is being used because skin grafts require an additional donor site such as thigh or abdomen. Potet et al. reported primary closure of the donor site by local flap (“keystone flap”),  and Nam et al. reported using an allogenic dermal matrix to repair the donor site . Recently, endoscopic-assisted radial forearm flap harvesting has been tried, Van Kouwenberg et al. reporting that it reduced linear scar length. This resulted in decreased donor site complications compared to conventional cases, such as numbness, graft loss, hypertrophic scarring, delayed wound healing, tendon exposure and complex regional pain syndrome. Moreover, based on patient surveys after surgery, cosmetic outcomes were better. Finally, functional scoring of such factors as overall discomfort, strength, flexibility, and cold sensitivity was higher .
In our study, the mean flap survival rate was 100% in the robot group and 90.9% in the conventional group. The mean survival rate was higher in the robot group but without statistical difference. Mean flap harvesting time was 107.2 minutes in the robot group and 67 minutes in the conventional group. Mean flap harvesting time was higher in the robot group, with statistical difference.
Table 2. Robot-assisted group harvesting time
Flap harvesting times for all robot-assisted cases were reviewed (Table 4). As experience increased, harvesting time showed a decreasing tendency. 3 of 4 recent cases showed 80-90 minutes, 10 to 20 minutes longer than the mean time for the conventional group, within the standard deviation range. There is also a learning curve for most kinds of surgeries. Many studies have reported a learning curve in robot-assisted surgery, which requires mastering device manipulation and 3-dimensional magnified viewing. Sanjeev K. et al reported that even experienced surgeons who had performed more than 1000 open prostatectomies underwent a learning curve when performing robot-assisted surgery. Overall surgery time showed a decreasing tendency until 50 cases experience and after 100 cases experience, overall surgery time showed a narrow distribution . Koh et al reported mean overall surgery time of 40 to 50 cases experience was 29% lower than that of the first 10 cases . We expect robotic flap harvesting time to decrease to a level similar to that of the conventional group after prolonged experience.
Robot-assisted surgery is technically more advanced than endoscopic-assisted surgery. Robotic devices provide magnified 3-dimensional images with a much higher resolution compared to endoscopic devices. While performing endoscopic-assisted surgery, a surgeon has to use long-shank hand instruments, which require caution due to their high sensitivity. However, robotic arms can freely connect and disconnect several robotic instruments such as Metzenbaum scissors, vascular clamps, and energy devices, allowing a surgeon to manipulate multiple instruments simultaneously. Furthermore, robotic arms are flexible and precise, allowing accurate manipulation free from physical barriers. These technical advances increase ease and accuracy of some kinds of surgery compared to the use of endoscopic devices.
Ease of flap harvesting, low rates of vascular anatomical variation, and adequate length and diameter of pedicle are the main advantages of radial forearm free flap. Adequate subcutaneous tissue thickness in forearm area provides better pliability, yielding good functional results after reconstruction. In case sensory reconstruction is needed, lateral cutaneous nerve can be included in reconstruction. Finally, overall surgery time can be reduced using the two-team approach.