Internal organ biopsy
A biopsy is the acquisition of cells or a fragment of tissue to examine their structure and thus establish an accurate diagnosis (morphological). If cells are taken from the organ, then a cytological examination is performed (from the Greek word "cytos" - cell), if a fragment of tissue-then a histological examination (from the word "histos" - tissue). This is necessary for volumetric formations of organs, less often-for diffuse diseases (first of all, for liver diseases, for example, hepatitis of unknown origin).
The main methods of obtaining morphological material are:
1. Fine needle aspiration biopsy (TAB), which allows you to obtain material for cytological examination;
2. Trepan-biopsy-obtaining a" column " of tissue using special needles to perform a histological examination;
3. Core-biopsy-obtaining the material with the help of special needles, inside which there is a harpoon-shaped core;
4. Brush biopsy-obtaining the material by scraping (for example, with a special brush from the area of the narrowed bile duct or bronchus).
Fine needle aspiration biopsy (TAB) is performed with Chiba needles(Shiba, Hiba, Chiba) with a diameter from 22 to 18G. The tip of the needle can be different: standard beveled, straight "cut" or scalloped (Fig.
TAB is performed as follows. Under constant ultrasound control, a puncture needle is inserted into the upper areas of the formation, avoiding vascular structures on the way. Remove the stiletto. The surgeon connects a regular 20ml syringe to the needle cannula and pulls the plunger to a volume of no more than 5-10ml. In conditions of constant aspiration, the operator harpoons the needle to the center of the formation and back. It is enough to make 2-3 such movements. After that, the plunger of the syringe is slowly released, without disconnecting the syringe from the needle.As soon as the pressure in the syringe is completely reduced, the syringe is disconnected, the needle is removed. The contents of the needle channel with a syringe and an internal mandrel are placed on the slides, "smearing" it as thinly as possible. The smaller the thickness of the smear, the more informative it will be. After that, the material is sent to specialists for research.
To get a column of tissue for histological examination, you can use special biopsy needles. Depending on the degree of automation of the process of obtaining a column of fabric, the following types of needles are distinguished:
- mechanical - both the extension of the groove and the extension of the cutting cannula are performed manually, by successive actions of the operator (currently not used);
- semi-automatic-the extension of the groove into the examined focus is performed manually, and the activation of the cannula is performed automatically with the help of a spring-loaded trigger mechanism (fig.)
General view of the semi-automatic needle for puncture biopsy
- automatic-usually involves the use of a "gun-needle" system, including an automatic multiple-use biopsy gun and a disposable biopsy needle (Fig.). Manually, only the biopsy needle is brought to the test site, while the process of extending the groove and activating the cutting cannula is carried out automatically by pressing the trigger of the gun.
General view of an automatic biopsy gun "loaded" with a disposable biopsy needle.
The advantages of semi-automatic needles include their greater maneuverability and delicacy (and, consequently, safety) when taking a biopsy from foci located close to important anatomical structures (neurovascular bundles, cavity walls, etc.). While after activating the gun spring straightening system, it is impossible to control the movement of the needle within the depth provided by the design. At the same time, the high speed of the introduction of the automatic needle groove ensures the production of high-quality samples from dense fabrics.
Under the control of ultrasound, the tip of the cocked semi-automatic needle is inserted into the peripheral part of the formation along the upper contour. Next, push the internal cannula with a "window" in the direction of the center of the pathological focus and press the pedal of the spring device of the needle. With the help of a spring mechanism, the inner cannula with a piece of tissue is instantly drawn into the channel of the main needle. After that, the needle is removed. The cannula is pushed out again, the resulting material is placed in a formalin solution and sent for examination. By placing the material on slides, you can get a cytological preparation.
When puncturing with a pistol, the tip of the cocked needle is brought to the edge of the pathological formation and the trigger is pressed. The whole procedure takes a few minutes.
Performing a biopsy under ultrasound control, as a rule, is not accompanied by serious complications. With impaired blood clotting, bleeding from the capsule of the punctured organ is possible. In all cases, after the manipulation, the patient is prescribed rest and cold at the puncture site for 2-3 hours, analgesics for pain. If the manipulation is performed on an outpatient basis, after this time, it is necessary to perform a control ultrasound of the abdominal cavity to exclude free fluid in the abdominal cavity or fluid accumulations under the capsule of the dotted organ. The exception is a biopsy of pancreatic formations, which should always be performed in a hospital setting, since there is a risk of developing acute pancreatitis.
