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Text | Amino Observation

Who will be the next Da Vinci? This may be the question that the medical industry is most concerned about.

The da Vinci surgical robot is unique with its revolutionary technology and has almost become synonymous with surgical robots. However, given the wide range of surgical applications and many pain points, the market has high hopes for surgical robots in different scenarios.

At present, microsurgery robots are not only the next technological highland, but also the next explosive field. After decades of exploration, this field is getting closer and closer to the "singularity" moment.

In February this year, Medical Microinstruments, a star overseas microsurgical robot company, received a huge amount of financing of US$110 million.

In China, companies including Angtai Precision and Dishi Medical have already made their presence known and continue to receive financing support to accelerate their progress. For example, Dishi Medical uses ophthalmic surgery as its entry point and has currently conducted confirmatory clinical trials in China.

So, will the next Da Vinci be born in the field of microsurgical robots?

/ 01/ Challenges that cannot be solved by humans

In the field of surgery, microsurgery is undoubtedly a high-tech field. The so-called microsurgery refers to the use of optical magnification equipment and microsurgical instruments to perform complex and precise operations in a very small range.

In a classic microsurgery operation, the doctor needs to use a microscope to explore and find blood vessels and nerves that are only one millimeter or even a few tenths of a millimeter in size, and then use sutures that are as thin as spider silk and measured in microns to accurately repair and suture each important blood vessel and nerve.

Because the field of view of microsurgery is usually only 2-3 cm, any slight shaking of the doctor's hands may directly affect the success or failure of the operation. Therefore, this requires the microsurgeon's technique to be steady, accurate, precise and skillful.

Currently, thanks to advances in microscope and instrument technology, microsurgeons are now able to perform supermicrosurgery by connecting blood vessels with diameters between 0.3 and 0.8 mm.

Based on the unique advantages of microsurgery, it has been widely used in various surgical specialties, including ophthalmology, otolaryngology, neurosurgery, plastic surgery, and urology.

Despite rapid advances, microsurgery still has significant limitations.

First, the probability of making mistakes is still high. Microsurgery requires extremely high precision and has a low tolerance for error. Even the slightest tremor may cause unnecessary injury. In theory, we need to avoid these injuries, but due to the complexity of the operation, the challenges are still numerous. Clinically, there are various complications, and the proportion is not low. Data show that the incidence of complications in epiretinal membrane peeling surgery ranges from 2% to 30%.

Second, long surgeries can easily bring more uncertainty. Depending on the patient's condition, a microsurgery operation can last from a few hours to more than ten hours or even more than thirty hours. Therefore, each operation is an extreme challenge to the doctor's skills and endurance. More importantly, this can lead to fatigue and increase the risk of accidental errors.

Third, and also the one that has the greatest clinical limitations, the training of surgeons is difficult and takes a very long time. This is because microsurgery requires high surgical skills from surgeons and requires extensive training before surgeons can perform such operations clinically. On the one hand, it places demands on the doctor's talent and patience, and on the other hand, it also requires a long period of training. A microsurgeon who can complete a finger replantation operation (a signature technique of microsurgery) generally needs three years of training, and the entire training cycle may take more than 10 years.

Therefore, under various limitations, the global medical community has explored the application of robotic technology in microsurgery and developed various microsurgical robot (MSR) systems.

The popularity is increasing. The number of MSR-related articles published each year from 2000 to 2022, the data is obtained by searching different keywords in Google Scholar. As can be seen from the figure, the number of MSR-related studies is generally on the rise.

All signs indicate that the MSR system has the potential to have a significant impact in the field of microsurgery.

/ 02/ The continued emergence of change makers

Based on the profound pain points, many companies around the world have launched efforts to tackle this field, and many different technical ideas have emerged during the exploration process.

First, the handheld robot system.

In a handheld robotic system, the surgical tool itself is modified into a micro-robotic system called a "robotic tool". The surgeon manipulates it to perform the surgical procedure. The robotic tool provides features such as tremor elimination, depth locking, etc., and is therefore also called a "steady hand".

"Micron" is a typical example, the core of which is to sense its own motion through a handheld manipulator and selectively filter out erroneous movements, such as hand tremors. The manipulator then generates stable motion at the tip of the tool through active error compensation. The Micron robot is easy to operate and is equipped with an arm holding true microsurgical instruments, which are easily placed in a holder and are compatible with traditional surgical microscopes.

Second, remote control robot system.

In the teleoperated robotic system, the surgeon manipulates the master module to control the slave module, which replaces the surgeon's hands to manipulate the surgical tools. The system integrates motion scaling and tremor filtering through servo algorithms. In addition, it also achieves three-dimensional perception by integrating tactile feedback or depth perception algorithms at the end of the surgical tools.

A typical example is the "Preceyes Surgical System", which consists of a computer, input motion controller, instrument manipulator, and operating table mounted headrest. Designed for optimal performance, the system features parallelogram linkage and adjustable counterweights to provide mechanical RCM, power failure protection, and minimized joint torque. The PSS uses dynamic scaling to convert gross motion into precise four-axis motion of the instrument tip. In addition, it utilizes OCT-based distance boundaries to prevent accidental motion and incorporates tremor filtering to reduce iatrogenic retinal trauma. Other features include tactile feedback, automatic instrument change, auditory feedback close to the retina, and an enhanced retraction mechanism for immediate removal of the probe in the event of an accident. These features improve precision and safety and reduce the risk of accidental tissue damage.

Third, a jointly operated robotic system.

In a co-manipulated robotic system, the surgeon and the robot manipulate the surgical tool simultaneously. The surgeon directly manipulates the surgical tool manually to control the movement, and the robot plays an auxiliary role, providing auxiliary compensation for hand tremors and allowing the surgical tool to be fixed for long periods of time.

The Disi Medical's Disi Micro-Front ophthalmic surgical robot is a typical example. In this surgical system, the doctor is the master hand and the slave hand is the robot, which moves according to the doctor's intention. The entire injection process is divided into several steps. First, the doctor controls the robot's gimbal to perform extraocular positioning, then intraocular positioning, and then the control handle is used to gradually bring the end closer to the lesion area of ​​the retina. If the drug needs to be injected into the subretinal position, the robot remains motionless, and human hands no longer intervene at this time, which takes about 3 minutes. Taking the injection of 200 microliters of liquid medicine as an example, the robot injects slowly. During the process, the doctor only needs to monitor the time, speed, and flow rate. After the injection, the eye is evacuated. The entire process is always under the doctor's supervision, and the decision is also made by the doctor.

Fourth, partially automated robot systems.

In a partially automated robotic system, specific procedures or procedural steps are automatically performed by the robot. The robot directly manipulates and controls the movements of surgical tools. Processed image information is provided to the robot as feedback and guidance. Visual information is also transmitted to the surgeon, who can provide override commands at any time to supervise the partially automated surgery.

In this field, the "IRISS" system is a typical example. Based on the "IRISS" system, surgeons remotely operate slave manipulators through a pair of customized master controllers and obtain visual information by observing intraoperative 3D visual feedback through a heads-up monitor. In addition, the system also provides tremor filtering and motion scaling functions to enhance the control performance and safety of robotic surgery. The performance of IRISS has been verified in ex vivo pig eyes, and surgeons have successfully performed a series of vitreoretinal surgeries using IRISS, including anterior lens capsule removal, vitrectomy, retinal vein catheterization, and other complex operations.

However, although there are many players exploring, objectively speaking, most companies are still in the early stages of exploration. Therefore, the explosion of this field still needs to wait for the arrival of the singularity moment.

/ 03/ Waiting for a singularity moment

Before these technological innovations can take hold, a host of complex issues must be addressed.

First of all, we need to adopt an interdisciplinary approach to effectively solve clinical and engineering problems. Although the functional positioning is very clear in logic - precise positioning and anti-shake - we first need to develop suitable hardware. This is not an easy task. For example, some functions required by the robot may not have ready-made robotic arms that can meet such high precision requirements. Therefore, we need to start from the basics and design it completely independently, including the construction of the control system and the design of the entire mechanical structure.

At the same time, the process of combining these high-precision parts into a system that meets the needs of clinical use is also quite complicated. For example, Dishi Medical mentioned that when the left eye needs surgery, the machine is placed on the left; when the right eye needs surgery, the prototype is placed on the right. In actual use, moving the robot will complicate the situation. The challenge is that the robot's movement range increases by a distance of pupil distance. Although it is only a few centimeters, the change in mechanical structure leads to a change in weight, and the corresponding load of the motor also changes... Many key components and mechanical structures need to be redesigned.

Secondly, the design of the robot must meet the doctor's operating conditions. The robot does not exist in isolation, and a deep understanding of the doctor's needs and pain points is a key know-how issue. Therefore, companies need abundant doctor resources. During the entire development process, professional engineers must work closely with surgeons to complete effective interactions. Some functions that do not meet clinical needs need to be eliminated. At the same time, they must comply with relevant standards for medical devices and have continuous iteration capabilities.

Even if the product is successfully developed, subsequent commercialization involves many problems, such as the education of doctors. Fundamentally speaking, robots can shorten the process of doctor education, for example, from 10 years to 5 years. But there is still a lot of work to be done to gain the trust of clinicians and patients.

In general, the performance of the product is "1", while issues such as doctor education are "0". At present, the core task of the microsurgical robot is to solve the problem of "1", and only then can it be qualified to talk about the accumulation of multiple "0s".