Date Published: April 27, 2020
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Author(s): Thiago Arantes de Carvalho Visconti, José Pinhata Otoch, Everson Luiz de Almeida Artifon.
To present new endoscopic robotic devices in the context of minimally invasive procedures with high precision and automation.
Review of the literature by December 2018 on robotic endoscopy.
We present the studies and investments for robotic implementation and flexible endoscopy evolution. We divided them into forceps manipulation platforms, active endoscopy and endoscopic capsule. They try to improve forceps handling and stability and to promote active movement.
The implementation and propagation of robotic models depend on doing what the endoscopist is unable to. The new devices are moving forward in this direction.
Endoscopy began as a gastrointestinal (GI) diagnosis method and became an important treatment method for GI pathologies nowadays. The equipment is in constant evolution, since the implementation of the electrical lamp, from the coming of flexible endoscopes, incorporation of ultrasonography and the recent development of robotic methods.
Flexible endoscopy is widely used for GI diagnosis and therapy, as it is little invasive and fast. Done by only one endoscopist and, most times, without general anesthesia3 . However, with the advance of its therapeutic purpose, the time and complexity of procedures have been drastically increasing, highlighting the operational limitations of flexible endoscopes. They have limitations regarding stability and forceps movement, with little possible angulation.
For ESD, it is necessary an adequate mucosal traction towards the lumen to expose the submucosal layer. The submucosal layer is dissected carefully, with hemostasis, until complete resection of the lesion. Mucosal traction needs to be constantly reallocated, due to angles and curves, especially in larger lesions. Those steps can take hours and bring technical difficulty. A range of instruments was developed to help the dissection, as different types of endoscopic knives and techniques to promote traction as cap-assisted12 ; metallic clips tied to strings13 , 14 and forceps attached to external channels15 , 16 . However, each one has its limitations. The cap-assisted technique reduces the vision field and sometimes does not promote the necessary traction. The clip is not possible to be pushed. Forceps in external channels can only perform traction in the same axis as the endoscope17 .
Developed by the Nanyang Technological University and the National University of Singapore, the MASTER system consists of two attached arms to a conventional double-channel endoscope with a forceps and an electrocautery hook. It allows nine degrees of freedom ( Fig. 1 ). It is necessary two endoscopists to manipulate ( Fig. 2 ). The surgeon controls seven degrees of freedom and the endoscopist introduces the set until the desired GI local and controls the positioning and orientation, besides the other two degrees of freedom, that are not motorized18 . Animal studies demonstrated effectiveness on ESD, full-thickness gastric resection and hepatic resection18 . This system was used on human for a few gastric, one esophageal and one colon ESDs23 , 24 .
Robotic assisted colonoscopy intends to improve the patient’s exam tolerance, to reduce pain, to reduce perforation risk and to promote cecal intubation regardless of the endoscopist ability. For those, it is necessary the colonoscope to have active motion and to mold to the colon. With robotic assistance, the physician could manipulate the colonoscope within a certain distance2 . The existing disposals have different insertion tactics. The majority uses inchworm-like movements or techniques derivate from balloon enteroscopy3 .
The use of endoscopic capsules, established in the last two decades, represents an appealing alternative to traditional endoscopic techniques for gastrointestinal screening for its lack of discomfort and need for sedation. However, the current models are passive devices that depend on intestinal mobility, and it is not possible to control the camera direction.
We present the researches and investments in the implementation of robotics and the evolution of flexible endoscopy. There is a search for systems that bring stability and greater controllability of the instruments for complex ESDs and NOTES. However, the new models presented have not yet been tested in large and challenging lesions, where they would show their full capacity and initial purpose, reducing technical difficulty and procedure time. For the implementation and diffusion of the robotic models, they must perform tasks that the endoscopist is incapable of, not only to reproduce what is already widely done. To move in this direction, the available models need to be constantly developed. Now to improve handling and stability; decrease the caliber and size of parts; and promote tactile sensation. However, this mission is not simple. Improved handling means increasing degrees of freedom, increasing the number of parts and instruments, making it harder to reduce the size of models.