Simulator for practicing surgical skills in resection of tumors of chiasmo-sellar region from endoscopic transnasal approach

Abstract

FIELD: neurosurgery; medical education.SUBSTANCE: used for training and practicing surgical skills in performing endoscopic transnasal resections of tumors of the chiasmo-sellar region (CSR). Providing the possibility of approaching real conditions by simulating intraoperative bleeding during tumor resection, the possibility of replacing the tumor within the model (potential for multiple use), the possibility of “getting the hang of it” not on endoscopy in general, but on practicing more specific stages of a real operation (tumor resection). The invention is a simulator for practicing surgical skills in resection of tumors of the chiasmatic-sellar region from an endoscopic transnasal approach, including a base in the form of cadaveric material from the head of a ram of the Ovis aries species with a frontal cut made through the nasal cavity, providing instrumental access to the region of the sella turcica, in the region of which a simulated tumor is installed with an integrated vascular system connected to a system for supplying and regulating simulated blood, contains a roller pump, a reservoir for collecting a blood-substituting solution, a reservoir for storing a blood-substituting solution, a sensor for the level of a blood-substituting solution and an electronic control module based on a microcontroller, configured to regulate the blood flow rate depending on changes in the level of a blood-substituting solution in the reservoir for storing a blood-substituting solution.EFFECT: expanding the functional capabilities of simulators for practicing surgical skills in resecting tumors of the chiasmo-sellar region from an endoscopic transnasal approach.4 cl, 4 dwg

Description

[0001] Application area

[0002] The invention relates to medicine, namely to the field of neurosurgery and medical education, and can be used for training and practicing surgical skills in performing endoscopic transnasal resections of tumors of the chiasmatic-sellar region (CSR).

[0003] Technology Level

[0004] Endoscopic transnasal neurosurgery places complex demands on the operator, including bimanual coordination, developed spatial orientation when viewing images in a two-dimensional endoscopic plane, proficiency with specialized instrumentation, and the ability to quickly and appropriately respond to acute intraoperative complications (including bleeding). These requirements determine the type and duration of the "learning curve" for these procedures: to achieve consistent surgical results with successful clinical outcomes and a low complication rate, endoscopic neurosurgeons require a significantly greater number of procedures compared to open surgeons.Thus, current systematic reviews of the literature on training in endoscopic transsphenoidal surgery show that the estimated number of cases required to overcome the initial stage of the learning curve in endoscopic transnasal neurosurgery requires performing an average of 40 to 100 operations, and the achievement of stable results and a reduction in the incidence of complications is observed after 100–200 interventions [Younus I, Gerges MM, Uribe-Cardenas R, Morgenstern PF, Eljalby M, Tabaee A, Greenfield JP, Kacker A, Anand VK, Schwartz TH. How long is the tail end of the learning curve? Results from 1000 consecutive endoscopic endonasal skull base cases following the initial 200 cases. J Neurosurg. 2020 Feb 7;134(3):750-760. doi: 10.3171 / 2019.12.JNS192600. PMID: 32032942. Or Candy NG, Ovenden C, Jukes AK, Wormald PJ, Psaltis AJ. The learning curve for endoscopic endonasal pituitary surgery: a systematic review. Neurosurg Rev. 2023 Sep 12;46(1):241. doi:10.1007 / s10143-023-02136-8.PMID: 37698777; PMCID: PMC10497425.].

[0005] A modern solution to this problem in global (including European) practice is the use of several types of training models to practice endoscopic neurosurgical skills before surgeons begin using this method in the operating room on live subjects. The main types of modern models are listed below:

[0006] Cadaver models are considered the "gold standard" for anatomical authenticity: they accurately reproduce the spatial relationships and tactile properties of tissues, allow for training in basic surgical techniques, contain realistic anatomy of structures, and enable the simulation of vascular crises. However, working with human cadaver material is fraught with ethical, logistical, and economic limitations, as well as limited reproducibility of certain scenarios (e.g., profuse bleeding). Specialized perfusion protocols have been described for simulating arterial bleeding on cadaver material.

[0007] Perfused / perfused models are typically either perfused cadaver models (where a dye or blood-substituting solution is circulated under pressure in the head or brain) or equivalent animal-based designs that simulate bleeding and allow for practicing hemostasis and emergency care techniques in vascular accidents. Perfusion allows for reproducing bleeding dynamics, evaluating tamponade techniques, coagulation, and assistant interactions, but requires complex hardware (pumps, reservoirs, sensors) and a regulated safety protocol.

[0008] Animal cadaver-based models are a relatively accessible and cost-effective option, offering good tactile realism for soft tissue skill training. Several studies have demonstrated the successful use of fresh or fresh-frozen pig heads for both basic endonasal training and replication of specific clinical scenarios.

[0009] 3D-printed and synthetic models—ensure high reproducibility, the ability to scale serial training for trainee surgeons, and the integration of replaceable modules (bones, tumor blocks, vascular channels). They are convenient for standardized skill assessment and sensor integration, but are inferior to cadaver models in terms of tactile realism and in simulating realistic hemostasis during electrocoagulation.

[0010] Virtual simulators (VR / AR) and "box-type" trainers. VR / AR systems allow for repeated and safe practice of complex manipulations, incorporating metric evaluation of actions and training scenarios with feedback. However, they are limited by the quality of tactile simulation and often require significant investment to achieve high realism. "Box-type" trainers (physical, without soft tissue) are useful in the early stages of motor and coordination training, but do not reproduce clinical problems (coagulation technique, tissue behavior during recession / separation, etc.).

[0011] A neurosurgical simulator for practicing transnasal endoscopic access is known from the prior art. It comprises an artificial skull fragment on a stand, a clamping device, and a removable module for practicing sella turcica trepanation and dura mater opening and suturing. The artificial skull fragment is a model of a skull fragment with a parasellar region. The skull fragment model includes a model of the nasal cavity bone structure, a model of the nasal cavity, and a model of the sella turcica. The sella turcica model is openly communicated with the nasal cavity model and is capable of fixing the module for practicing sella turcica trepanation and dura mater opening and suturing, performed using a clamping device (patent RU 2789507 C2, publication date 04 / 15 / 2022).

[0012] A simulator for performing vascular surgery is also known, comprising an electric power source, a tubing system, valves, a single-acting electric hydraulic pump installed to provide fluid flow through the tubing system, a buffer tank, and a model blood vessel made of biological or synthetic material and connected to the tubing system via valves. Additionally, a rectangular pulse generator and a pulse-width modulation controller are connected to the electric hydraulic pump, capable of generating pulsed fluid flow with controlled pressure. A potentiometer is connected to the pulse-width modulation controller, and the square-wave generator potentiometer is connected to the square-wave generator. A pressure gauge is used to measure the pressure in the tubing system.The indicator LED is used to monitor the pulse frequency and is connected to a rectangular pulse generator. (Patent RU 2836022 C1, publication date 10.03.2025.)

[0013] The closest analogue to similar ones in subject matter and in terms of requirements for anatomical accuracy (often tested on cadavers during validation) is a simulator for mastering skills in endonasal endoscopic surgery, designed to master and improve manual skills in working with medical instruments under the control of an endoscopic system, which are necessary for performing the basic surgical techniques of endonasal endoscopic surgery.The simulator comprises a stand on which a nasal cavity model is mounted, made in the form of a removable cylinder with the ability to change its position in space, wherein the interior of the nasal cavity model is designed with the ability to insert an endoscope and an auxiliary instrument into it, and also contains inside it a replaceable element simulating the structure of the nasal cavity, the replaceable element is made in the form of an insert that is subject to destruction as a result of exposure to an instrument for endonasal endoscopic surgery, and the nasal cavity model is made in the form of a truncated cylinder, the beveled end of which is located on the side of insertion of the endoscope and the instrument for endonasal endoscopic surgery, and the longest generatrix of which is located above relative to its axis. (patent RU 180078 U1, publication date 01.06.2018).

[0014] Thus, each of the aforementioned existing categories of training solutions has a combination of advantages and limitations: cadaver and perfused models provide maximum realism but are limited by availability and cost; 3D and VR models are scalable and standardizable but have limitations in tactile properties; perfused animal models (e.g., based on a ram's head) represent a compromise between realism and accessibility. Understanding these limitations dictates the need for hybrid solutions—models that combine anatomical authenticity, reproducibility, and the ability to simulate bleeding, while remaining affordable and easily scalable for surgical training programs.

[0015] The technical result achieved by the claimed invention consists in expanding the functional capabilities of simulators for practicing surgical skills in resecting tumors of the chiasmatic-sellar region from an endoscopic transnasal approach.

[0016] Disclosure of the essence of the invention

[0017] The technical result consists in solving the above-mentioned technical problem and providing the possibility of approaching real conditions by simulating intraoperative bleeding during tumor resection, the possibility of replacing the tumor within the model (potential for multiple use), the possibility of “getting the hang of it” not on endoscopy in general, but on practicing more specific stages of a real operation (tumor resection).

[0018] The stated technical problem is solved, and the technical result is achieved in a simulator for practicing surgical skills in resection of tumors of the chiasmatic-sellar region from an endoscopic transnasal approach, including a base in the form of cadaveric material from the head of a ram of the Ovis aries species with a frontal cut made through the nasal cavity, providing instrumental access to the region of the sella turcica, in the region of which a simulated tumor is installed with an integrated vascular system connected to a system for supplying and regulating simulated blood, contains a roller pump, a reservoir for collecting a blood-substituting solution, a reservoir for storing a blood-substituting solution, a blood-substituting solution level sensor and an electronic control module based on a microcontroller, configured to regulate the blood flow rate depending on changes in the level of the blood-substituting solution in the reservoir for storing a blood-substituting solution.

[0019] An additional feature is that the simulated tumor is designed to be electrically conductive when using electrocoagulation.

[0020] An additional feature is that the vascular system contains tumor capillaries.

[0021] An additional feature is that the blood substitute solution contains glycerin to simulate the density of blood.

[0022] An additional feature is that it is designed with the ability to replace the simulated tumor.

[0023] An additional feature is that it is designed with the ability to quantitatively assess the volume of intraoperative blood loss.

[0024] Brief description of drawings

[0025] The invention is explained by illustrations, where Fig. 1 shows a diagram of a closed blood flow system, where: 1 - Electronic control module; 2 - Reservoir for blood-substituting solution; 3 - Blood-substituting solution level sensor; 4 - Roller pump; 5 - Tumor capillary system; 6 - Roller pump motor driver.

[0026] Fig. 2 - 3D reconstruction of CT of the organic part of the model with a contrasted tumor, sagittal section.

[0027] 7 – Nasal cavity, truncated in the frontal plane; 8 – Polymer clay base, performing a supporting function; 9 – Simulated tumor (a 5% iodine solution was added to the gelatin composite to contrast the demonstration model).

[0028] Fig. 3 - the appearance of the device

[0029] Fig. 4 shows the appearance of the device during use.

[0030] Implementation of the invention

[0031] The claimed model is a physical anatomical model based on the cadaveric head of an Ovis aries ram, with an integrated vascular system simulating blood flow in a simulated tumor. The model reproduces the anatomical features of the transnasal surgical approach and provides realistic manual and visual anatomical accuracy.

[0032] Structurally, the model includes:

[0033] - an organic part consisting of a ram's head with a frontal cut through the nasal cavity, which makes it possible to use standard endoscopic instruments of normal length;

[0034] - a simulated tumor made of gelatin composite with a built-in vascular system containing polyvinyl chloride capillaries through which a blood-substituting solution circulates and installed in the sella turcica region;

[0035] - a system for supplying and regulating simulated blood, including a roller pump, reservoirs for collecting and storing blood-substituting solution, a blood-substituting solution level sensor, and an electronic control module that adapts the bleeding intensity to the volume of blood loss.

[0036] The gelatin composite with 0.9% sodium chloride solution used allows the use of electrosurgical instruments (bipolar and monopolar electrocoagulators) during tumor removal, providing tactile and visual sensations close to the conditions of a real operation.

[0037] Implementation example

[0038] A frontal section through the nasal cavity, as well as an axial section and skeletonization of the skull base, were performed on freshly frozen ram head cadaver. The resulting anatomical space visualizes the chiasmatic-sellar region of the ram skull base, into which a simulated tumor with an integrated vascular system of PVC capillaries is inserted. The system is connected to a simulated blood supply and regulation system, consisting of a pump system including a roller pump, reservoirs, and a microcontroller control unit.

[0039] When the pump is connected to the power supply, circulation of the blood-substituting solution is ensured, simulating natural blood flow. When the PVC capillaries are coagulated, the flow of the colored solution in the treatment area ceases.

[0040] The design of the model allows for multiple use due to the replacement of the tumor block, as well as quantitative assessment of the volume of intraoperative blood loss.

[0041] The developed model was tested during the "Transnasal Neurosurgery" competition as part of the XXXIII M. I. Perelman Olympiad in 2025 and received high marks from experts and participants for its realism and reproducibility.

Claims

1. A simulator for practicing surgical skills in resecting tumors of the chiasmatic-sellar region from an endoscopic transnasal approach, including a base representing the head of a domestic sheep with a frontal cut through the nasal cavity for access to the sella turcica region, an imitation of a tumor installed in the sella turcica region with the possibility of replacement, made of a gelatin composite with a 0.9% sodium chloride solution and equipped with a built-in imitation of a vascular system connected to a system for supplying and regulating a blood-substituting solution, and a system for supplying and regulating a blood-substituting solution, including a roller pump, a reservoir for collecting a blood-substituting solution, a reservoir for storing a blood-substituting solution, a blood-substituting solution level sensor and an electronic control module including a microcontroller and configured to adjust the flow rate depending on a change in the level of a blood-substituting solution in the reservoir for storing a blood-substituting solution.

2. The simulator according to paragraph 1, characterized in that the imitation of the built-in vascular system contains imitators of tumor capillaries.

3. The simulator according to item 1, characterized in that the blood substitute solution contains glycerin to simulate the density of blood.

4. The simulator according to paragraph 1, characterized in that it is designed with the possibility of quantitatively assessing intraoperative blood loss.

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