Background

Minimally invasive surgery (MIS) is a surgical technique used to treat some non-cancerous and cancerous conditions [1]. Over the past several years, there has been a rise in the utilization of minimally invasive surgery for surgical procedures. MIS is less invasive than open surgery as it involves the use of small instruments. This approach offers several advantages, such as reduced surgical trauma and complications associated with the incision, including postoperative pain and blood loss. Additionally, MIS results in shorter rehabilitation and hospitalization periods, as well as a better cosmetic outcome [2, 3].

However, the MIS technique results in a reduction in in-depth perception due to the use of a two-dimensional monitor, loss of tactile sense, and the fulcrum effect of instruments [2]. Advancements in robotic technology have also driven the progress of laparoscopic devices by introducing new capabilities. Due to the limited number of operation channels, it is imperative to have instruments that can do several duties, allowing the surgeon to use the other hand with a different instrument.

This work describes the development of a novel surgical prototype with four distinct functions: irrigation, suction, bipolar coagulation, and neurostimulation.

Technique

In order to create the initial 8-mm prototype, a preexisting 5-mm suction-irrigator was altered by attaching an external aluminum cannula. The electrical connections were established using a cable severed from a LigaSure™ device. To construct the 8-mm prototype, the initial action was altering the distal end of the inner cannula by removing a semicircular shape. The next stage involved trimming the lengthier aluminum outer cannula to the appropriate length and preparing its distal end in a manner similar to that of the inner cannula. Figure 1 displays the entire prototype. A 5-mm prototype was constructed using a modified reusable 3.5-mm suction-irrigator, which was externally covered with a 5-mm insulated stainless steel material. A compact and sturdy proximal connection chamber, constructed from stainless steel, was supplied to establish a connection between a traditional silicon bipolar cable, as seen in Fig. 2. A specific resin was utilized to secure the inner cannula to the outer cannula. Additionally, the 5-mm prototype proximal connection chamber was filled with resin.

Fig. 1
figure 1

First 8-mm prototype

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Fig. 2
figure 2

Proximal component of the 5-mm prototype

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The 5-mm prototype was manufactured in a similar manner as the 8 mm, with the exception of the proximal end, where the electrical connections are sealed with epoxy in the stainless-steel chamber to enhance the instrument’s strength and durability. The many constituents of the instrument are delineated in Figs. 1 and 3. The device was registered with the World Intellectual Property Organization on the 12th of November 2020 with international publication number WO 2020/225835 A1.

Fig. 3
figure 3

Medial (left) and distal (right) components of the 5-mm prototype

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Case and Discussion

During the preliminary stage, the effectiveness of bipolar coagulation was evaluated using in vitro testing. The prototypes underwent testing on steaks (Fig. 4) using hematoxylin–eosin staining to assess the extent of coagulation (Fig. 5). The activation of the electrical generator was halted prior to the occurrence of the carbonization phenomenon.

Fig. 4
figure 4

Multiple coagulations on a steak with an 8-mm prototype

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Fig. 5
figure 5

Thin vertical (left) and horizontal (right) slices colored with hematoxylin–eosin staining showing the extension of coagulation. Note that the mark on the ruler indicates millimeters

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An optimal level of coagulation was achieved between the two branches of the distal instrument, indicating a robust and targeted coagulating capability. The region of the steak that undergoes coagulation is readily visible in Fig. 4.

The coagulation can extend to a thickness of around 3–4 mm, as seen in Fig. 5.

The experiments indicate that this new tool could selectively cause blood clotting between the two furthest branches. Thus, its effectiveness is potentially sufficient to provide proper tissue hemostasis.

Moreover, the neurostimulation capability, which has not yet been verified, is theoretically assessed as effective based on the structural features of the device. Although further tests are needed, this might potentially be the optimal function to utilize in neuropelveology [4]. The potential of the gadget to activate the nerves could be crucial for identifying the pelvic nerves, particularly for surgeons specializing in endometriosis and pelvic radical surgery [5, 6].

While the prototypes have only been tested on animal models, the purpose of developing these devices is to explore new possibilities for the design of more instruments. These instruments would be subsequently evaluated on live subjects to assess their effectiveness in coagulation and neuromodulation.

Conceivably, the prototypes have great potential as a tool for pelvic surgery. This is due to the limited space available during pelvic dissection, making it crucial to have the ability to promptly manage any potential bleeding that could obstruct the surgical area.

Conclusion

It is technically possible to construct a surgical suction-irrigation system that includes coagulation and potentially neuromuscular stimulation capabilities. However, further experimentation, validation, and refinement are necessary. This instrument has the potential to be a highly valuable tool for surgical procedures, particularly when used in the field of neuropelveology.