RU2843425C1 - Method for simulating abdominocentesis in laboratory animals - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention refers to medicine, namely to experimental surgery, and can be used in simulating abdominocentesis in laboratory animals. A rat’s abdomen is incised for 0.2-0.3 mm. A syringe having a sealed passage is used to create a vacuum within the incision to perform laparolifting. A Veress needle is inserted through a syringe canal into the wound, and a laparolifting procedure is followed by puncturing an abdominal wall thickness with applying a pneumoperitoneum. Abdominocentesis is completed by means of a trocar.

EFFECT: method is easy-to-use, requires no special equipment, enables controlling the introduction of the first trocar that eliminates injuries of the abdominal organs, reduces a risk of postoperative complications accompanying abdominocentesis due to laparolifting with using a syringe.

1 cl, 5 dwg, 1 ex

Description

Field of technology

The invention relates to the field of medicine, namely to experimental medicine, and can be used in scientific research in modeling safe abdominocentesis on laboratory animals.

State of the art

Abdominocentesis is a minimally invasive procedure that allows the doctor to obtain a sample of fluid from the abdominal cavity for diagnostic purposes. In this regard, the study and description of the features of laparoscopic visualization and orientation in the abdominal cavity in various pathologies is a relevant area in abdominal surgery to this day. A dangerous stage of laparoscopic surgery is the introduction of the “first” trocar (Beburishvili A.G., Mikhin I.V., Vorobyov A.A. et al. // Surgery. - 2004. - No. 6. - P. 27-30; Azvedo J.L., Azvedo O.C., Miyahira S.A., Miguel G.P., Becker O.M. et al. Injuries caused by Veress needle insertion for creation of pneumoperitoneum: a systematic iterature review // Surg. Endosc. - 2009. - Vol. 23. - No. 7. - P. 1428-1432), since a number of potentially possible complications pose an immediate threat to the patient's life (Ahmad G., Duffy J.M., Watson. A. Laparoscopic entry techniques and complications // Int. J. Gynecol. Obstet. - 2007. - Vol. 99. - №1. - P. 52-55; Roviaro G.C., Faroli F., Saguatti L. et al. Major vascular injuries in laparoscopic surgery // Surg. Endosc. - 2002. - Vol. 16. - P. 1192-1196). According to the literature, the greatest number of intra-abdominal complications occur with "blind" introduction of the first trocar. Baranov G.A., Zavyalova N.I., Karbovsky M.I., based on the analysis of 6106 laparoscopic interventions, found that at the stage of access to the abdominal cavity without preliminary imposition of pneumoperitoneum with the "single-puncture" technique, serious complications occurred in 0.13% of patients, and the mortality rate was 0.03%.

There is a known method of safe insertion of a trocar into the abdominal cavity to create an "air cushion" in it, which reduces the possibility of damage to blood vessels and internal organs and increases the efficiency of the operation - diagnostic laparoscopy, including the imposition of pneumoperitoneum (PP) - one of the most important stages of any laparoscopic operation. Gas is introduced into the abdominal cavity, lifting the abdominal wall and creating the space necessary for work. The created "air cushion" increases the distance between the abdominal wall and internal organs at the moment of insertion of the trocar. The specified pressure is maintained throughout the operation. First, the patient's skin is dissected throughout its thickness at the intended point of insertion of the needle of the instrument for imposition of pneumoperitoneum (PP), which is also called the Veress needle. Tactilely, the surgeon usually feels the passage of two obstacles - the aponeurosis and the peritoneum. After the puncture, pendulum-like movements of the needle should be avoided, as they can lead to damage to internal organs and blood vessels (see patent RU No. 40874, IPC A61B 17/32, published 10.10.2004), preventing gas from entering the tissue before the needle penetrates the abdominal cavity.

The method allows for a fairly safe pneumoperitoneum to be imposed, but it does not provide the ability to control the process of inserting the “first” trocar and, thus, cannot fully guarantee the prevention of trocar injuries.

A method of laparocentesis is known, carried out using a device described in the author's certificate SU 1187798 (IPC A61B17/32, published 30.10.1985). According to the method, after the pneumoperitoneum is imposed, the device is inserted into the laparoscope sleeve or into the photolaparoscope sleeve and placed in the operator's right hand so that the index and middle fingers engage the ring handles, and the thumb is on the balloon. Having positioned the instrument perpendicular to the anterior abdominal wall and having pressed the nozzle tightly to it, sharply press the balloon with the thumb, while the force is transmitted through the guide tube to the knife, the blade of which extends from the nozzle by 2-3 mm and cuts the skin. The length of the knife blade's exit from the housing is adjusted by rotating it along the thread of the holder. The operator's hand feels and the eyes control how the device, together with the laparoscope sleeve, begins to smoothly sink into the tissues of the anterior abdominal wall. Since the tissues are first dissected with a knife and then moved apart with a conical attachment, the force developed is insignificant. The instrument continues to advance until an obstacle is felt - evidence that the attachment with the extended knife blade has approached the aponeurosis. After this, the thumb smoothly releases the balloon, which returns to its original position with the help of a spring, while the knife blade goes into the attachment. To dissect the aponeurosis, the thumb is moved to the balloon and, with light pressure on the holder, the thumb sharply presses on the balloon, while the knife blade comes out of the attachment and dissects the aponeurosis, after which the knife is removed again. The instrument is advanced through the loose layers of the anterior abdominal wall - muscles, preperitoneal fat and peritoneum - only by the attachment without extending the blade by lightly pressing on the holder. At the moment the attachment penetrates the abdominal cavity, the pneumoperitoneum gas enters the elastic balloon through the hole in the attachment, the guide tube and inflates it. The operator's hand feels a "falling through". Further advancement of the device is stopped, it is removed from the laparoscope sleeve, and an optical system for examining and photographing the abdominal organs is inserted into the said sleeve.

However, this method is not effective enough.

A method of laparolifting is known (see patent RU 2257155, IPC A61B17/00, published 27.07.2005), in which the anterior abdominal wall is lifted during laparoscopic operations by traction on fixing threads. Fixing threads are secured to the trocar and to the arch above the operating table.

However, the method is technically complex and can only be implemented using special fixing threads.

A method for treating and preventing gastric torsion in dogs is known (see patent RU 2503429, IPC A61D 1/00, published 10.01.2014), in which a surgical operation for endoscopically assisted gastropexy is performed in several stages. According to the method, laparoscopic visualization of the stomach, fibrogastroscopy with filling the stomach with gases and laparoscopic assessment of the features of the stomach topography and determination of the gastropexy site are carried out. For laparoscopic visualization of the stomach, a laparoscopic examination of the abdominal cavity is used using an endoscope with a diameter of 2.7-10 mm and a viewing angle of 0-30 degrees. After preparing the surgical field according to the generally accepted technique, percussion studies are carried out to identify the abdominocentesis point. Abdominocentesis is performed using a Veress needle with subsequent insufflation of carbon dioxide until a pressure of 7-8 mm Hg is created in the abdominal cavity. After this, abdominocentesis is performed with a trocar with an atraumatic stylet in the area of the middle of the distance from the navel to the pubic bones, after which the Veress needle is removed from the abdominal cavity and the gas supply is switched to the trocar tap. The next step is to insert an endoscope and examine the abdominal cavity, assess the anatomical and topographic landmarks for performing gastropexy with an empty stomach. The site for gastropexy is chosen: on the stomach, the area of transition of the body of the stomach to the antral section in the avascular zone, on the abdominal wall, the site of projection of the selected area of the stomach onto the abdominal wall.

However, the method is not effective enough and is difficult to use.

A method for performing an endoscopic examination using a laparoscope (5 mm in diameter, 30-degree viewing angle) and an endoscopic video system is known (Shumakov N.I. Topographic justification for diagnostic laparoscopy in dogs. Small domestic and wild animals. - 2014. - No. 1. - P. 29-32). In the proposed method, laparoscopy was performed under general anesthesia. After the animal was anesthetized, the surgical field was prepared using the generally accepted technique. Abdominocentesis was performed using a Veress needle with subsequent insufflation of carbon dioxide (pressure 7-8 mm Hg). Using a 5 mm trocar with an atraumatic stylet, the most suitable place for examining different parts of the abdominal cavity was determined in different areas of the abdominal wall. Then the endoscope was inserted and a visual examination of the abdominal cavity began. If necessary, an additional trocar was installed for inserting the manipulator. The operation was completed by removing gas from the abdominal cavity and layer-by-layer suturing of the abdominal wall.

However, the method does not allow the use of larger diameter trocars without expanding the surgical access, which increases the trauma of the intervention and the risk of complications.

The state of the art does not provide methods for modeling abdominocentesis on laboratory animals, in particular rats.

Disclosure of the essence of the invention

The technical problem of the claimed invention is the development of a method for safe abdominocentesis in an experiment on laboratory animals.

The technical result consists in eliminating trauma to abdominal organs.

The technical result is achieved by the fact that in the method of modeling abdominocentesis on laboratory animals, according to the solution, a 0.2-0.3 mm skin incision is made on the abdomen of an anesthetized laboratory animal - a rat, vacuum laparolifting is performed in the incision area using a syringe having a sealed channel through which a Veress needle is inserted into the wound and, without stopping the vacuum laparolifting, a puncture is made in the entire thickness of the abdominal wall with the imposition of pneumoperitoneum, and abdominocentesis is completed using a trocar.

Brief description of the drawings

The invention is explained by drawings, where Fig. 1 shows a skin incision (0.2-0.3 mm) on the abdomen of a laboratory rat; Fig. 2 shows a reproduction of laparolifting with a 0.5 ml syringe; Fig. 3 shows a reproduction of a puncture of the abdominal wall with a Veress needle and the imposition of pneumoperitoneum; Fig. 4 shows a syringe having a sealed channel in the piston in which the Veress needle is placed; Fig. 5 shows the result of a diagnostic laparotomy, reflecting the absence of trauma to the abdominal organs.

The following positions are indicated on the drawings:

1 - skin incision;

2 - syringe;

3 - syringe plunger;

4 - Veresh needle;

5 - sealed channel in the piston.

Implementation of the invention

The method is carried out as follows.

General anesthesia of laboratory animals - rats - is performed according to the standard technique. Under aseptic conditions, a 1 x 0.2-0.3 mm skin incision is made on the rat's abdomen, previously shaved, along the midline in the mesogastric region (Fig. 1). A 0.5 ml syringe 2 with a sealed channel in the piston 5 (Fig. 4) is applied to the abdominal wall, positioning the wound in its lumen. By moving the piston 3, a vacuum is created in the syringe 2, vacuuming the wound area and fixing it in the syringe. Laparolifting is performed by traction of the syringe (Fig. 2). A Veresh needle 4 is inserted into the wound through the channel of the piston of the syringe 3 and, without stopping the vacuum laparolifting, a puncture is made through the entire thickness of the abdominal wall (Fig. 3). Next, according to the accepted method, pneumoperitoneum is applied through the Veress needle and, using it, abdominocentesis is completed using a trocar, which is used to insert the laparoscope and instruments. The Veress needle is connected to an air source to create an air cushion in the abdominal cavity.

An example of specific implementation.

The studies according to the method described above were conducted on 20 female laboratory rats of the Standard breed weighing 200±50 g. All manipulations and keeping of animals were regulated by the Ethics Commission of the Federal State Budgetary Educational Institution of Higher Education “Saratov State Medical University named after V.I. Razumovsky” of the Ministry of Health of the Russian Federation (Protocol No. 7, 15.07.2024). The conditions of keeping laboratory animals in the vivarium are regulated by RD-APC 3.10.07.02-09 “Methodological recommendations for keeping laboratory animals in vivariums of research institutes and educational institutions”, the order of the Ministry of Health of the Russian Federation dated 01.04.2016 No. 199n “On approval of the rules of good laboratory practice”, GOST 33216-2014 “Guidelines for the maintenance and care of laboratory animals. Rules for the maintenance and care of laboratory rodents and rabbits" (updated on 01.01.2021).

During the diagnostic laparotomy, it was established that the reproducible method is safe and non-traumatic for the abdominal organs, which is confirmed by the absence of damage to the abdominal organs (Fig. 5). In addition, the use of this method allows to reduce the risk of postoperative complications, such as postoperative peritonitis, abdominal abscesses, postoperative intestinal obstruction and intra-abdominal bleeding.

Claims (1)

A method for modeling abdominocentesis on laboratory animals, characterized by the fact that a 0.2-0.3 mm skin incision is made on the abdomen of an anesthetized laboratory animal - a rat, using a syringe with a sealed channel, a vacuum is created in the incision area, performing laparolifting, a Veress needle is inserted into the wound through the syringe channel and, without stopping laparolifting, a puncture is made in the thickness of the abdominal wall with the imposition of pneumoperitoneum, and abdominocentesis is completed using a trocar.