This retrospective review of 12 cases of submandibular gland resection using an ORBEYE exoscope revealed no postoperative complications, including nerve palsy and vasculature preservation. To our knowledge, this is the first study to examine the usefulness of an exoscope in submandibular gland resection. An exoscope is advantageous because of its superior ergonomics, with reduced fatigue due to its free viewing angle, and its educational significance, as it enables screen sharing with the same surgical field of vision as the surgeon. Moreover, it enables to perform surgery while viewing high-resolution 3D images under magnification [8,9,10,11]. In head and neck surgery, usually performed with the naked eye, the ORBEYE exoscope’s excellent autofocus function and small mirror body allow the surgeon to avoid interference from instruments and secure a smooth surgical field without stress. Additionally, its ability to magnify nerves and blood vessels is extremely useful.

In the conventional method, some critical structures for level 1 neck dissection involving submandibular gland excision, such as the marginal mandibular, lingual, and hypoglossal nerves, and the submandibular duct, may not be identified [2]. Paralysis of the mandibular marginal branch of the facial, lingual, and hypoglossal nerves in submandibular gland surgery occurs in 1–7%, 0.5–4.4%, and 0–1.4% of cases, respectively [3,4,5,6]. A lack of confirmation can cause these nerve injuries and adhesions between the lingual nerve and the submandibular canal, as observed in sialolithiasis. In the present study, we believe these structures were preserved because they could be clearly visualized under the ORBEYE exoscope.

The facial artery can be preserved by partially burying it in the glandular tissue. This requires careful blunt dissection of the submandibular gland along its course and the division of several small arterial branches from the artery to the gland to free it from the gland. The exoscope helped magnify the surgical field by delicately dissecting the submandibular gland, detaching the artery, and ligating small arterial branches from the artery to the gland. Facial veins rarely run embedded in the submandibular gland [12]. However, the vein requires ligature processing of small venous branches, and the benefit of obtaining magnified views in venous processing, which is prone to vascular collapse, is considered crucial. Cutting and ligating the facial artery are common practices in conventional submandibular surgery; however, facial artery preservation is important because of its role in blood flow to the lower face and platysma muscle. The facial artery should not be routinely ligated and sacrificed because it is a crucial recipient vessel in head and neck reconstructive surgery [12].

Endoscopic and robotic techniques have been reported for submandibular gland surgery, the advantages of which are primarily cosmetic appeal and high magnification [1, 13,14,15,16,17,18,19]. However, they are not widely used, possibly because of the complexity of preparation and cost. In contrast, the ORBEYE exoscope does not require special settings or devices other than drapes, such as ultrasonic coagulation devices, and the surgical instruments are almost similar to those used in conventional surgery. Furthermore, the difference in the direction of the field of view compared with that of classical submandibular surgery may also hinder its adoption by surgeons. Therefore, using the exoscope requires familiarity with hand–eye coordination; however, because the direction of the field of view is the same, the hurdle to exoscope adoption may be low. Reports of endoscopic and robotic surgery have generally shown promising results in preserving the mandibular marginal branch and other nerves; however, the facial arteriovenous system is ligated, except for robotic resection through a trans-hairline approach [14,15,16,17,18,19]. The benefits of preserving the facial arteriovenous system remain unknown; however, preserving large-diameter vessels is not likely to be disadvantageous. To our knowledge, there have been no reports on the use of an exoscope. The ORBEYE™ system is priced at approximately $412,000, which is considered cost-competitive compared to conventional high-end surgical microscopes with equivalent optical and imaging capabilities. Additionally, the system requires minimal recurring expenditure, with disposable sterile drapes being the only consumable item.

This preliminary study provides promising results but has some limitations. The main limitation is the small number of patients included, which may affect the results. Therefore, it will be necessary to conduct a prospective study of submandibular gland surgery, comparing the conventional method with the ORBEYE exoscopic approach in a larger number of patients in the future. Visualization of delicate structures, such as nerves and blood vessels, in greater detail may lead to lower complication rates and educational benefits. Using the ORBEYE exoscope has educational significance for instructors and observers. It is essential to understand anatomical details when learning a surgical technique, and understanding how to handle these structures and surrounding tissues from the surgeon’s perspective can be helpful in improving the technique; ORBEYE makes this possible.