RU223721U1 - Tweezers for removing foreign metal magnetic bodies from a narrow and deep brain wound using cylindrical neodymium magnets - Google Patents

Abstract

The utility model relates to the field of medicine, in particular to neurosurgery, and can be used to remove foreign metal magnetic bodies in a deep and narrow wound of the brain during surgical treatment of craniocerebral wounds. The purpose of the utility model is to develop a line of bayonet-shaped microsurgical tweezers with the ability to rigidly grip a cylindrical neodymium magnet of different diameters for working at different depths in a narrow brain wound. The solution to this problem is ensured by the fact that the bayonet form of tweezers made of stainless medical steel with an angle of inclination of the working part (branches) of 15° relative to the handle with transverse notches for tactile sensations of the instrument, which allows not to limit the view of the surgical field through the eyepieces of the microscope, the ends of the jaws are formed concave shape, with a radius of curvature corresponding to the diameter of the neodymium cylindrical magnet used. The stable position of the magnet is facilitated by the internal curvature of the ends of the jaws with internal transverse notches and the ferromagnetic composition of the tweezers, which ensures the attraction of the magnet to the jaws, which prevents their spontaneous opening with subsequent loss of the magnet. The length of the working part of the tweezers is 55 mm, 75 mm, 95 mm and 115 mm, which allows, depending on the depth of the wound, to use a tool of the required length and ensure ease of work. Marks placed on the upper and outer surfaces of the jaws in increments of 10 mm allow you to navigate in the depth of immersion along the wound channel, correlating the surgeon’s actions with preoperative images. 5 ill.

Description

The utility model relates to the field of medicine, in particular to neurosurgery, and can be used to remove foreign metal magnetic bodies in a deep and narrow wound of the brain during surgical treatment of craniocerebral wounds.

In peacetime, and more often, war, or any armed conflicts and modern types of wars, mine-explosive wounds are accompanied by damage to the head and skull with deep penetration of metal fragments into the substance of the brain. According to many authors, since the beginning of the 20th century, in the structure of combat injuries to the skull and brain, the proportion of fragmentation wounds has increased over time and reached 93% [Shulev Yu.A. – “Features of surgical treatment of mine-explosive injuries of the skull and brain in mountainous desert conditions.” - diss. Ph.D. L. – 1986. – 230 p.]. Often, such foreign bodies (FBs) are metal magnetic objects of various shapes and sizes, which, if anatomically accessible, in most cases should be removed. The extraction of metal bodies was previously recognized by most authors as mandatory and considered an ideal, although in half of the cases it was not possible. Despite the widespread use of the method of probing the wound channel for removing metal FB, proposed by N.N. Burdenko (1943) [Burdenko N.N. Key issues of neurosurgery. – Question. Neurosurgery, 1943, vol. 7, No. 3, p. 3-21], according to the experience of the Great Patriotic War, the use of magnets was not widespread [Shulev Yu.A. – “Features of surgical treatment of mine-explosive injuries of the skull and brain in mountainous desert conditions.” - diss. Ph.D. – L. – 1986. – 230 p.]. At the same time, according to B.A. Samotokin, the widespread introduction of the use of pin magnets into the practice of neurosurgeons occurred later, in subsequent armed conflicts [Samotokin B.A. Gunshot wounds of the skull and brain. – In the book: Materials of the United Scientific. Sessions of the USSR Academy of Medical Sciences and Military Medical Academy. on modern problems of traumatology. L., 1974, p. 40-42].

Removing IT from the depths of a brain wound seems to be a rather dangerous undertaking. It was recommended to remove large metal bodies that do not penetrate the ventricular cavity, located at a shallow depth, with great care. In this case, for the extraction itself, a narrow cranked forceps was used. Since the First World War, high-power electromagnets have been tested and used to extract iron and steel fragments from deep within the brain. However, this method is very dangerous: under the powerful action of the magnetic field, a deeply located foreign body rushes outward with great force and not always along a safe trajectory, and not along the entry trajectory, as a result of which vascular damage is possible [Wartime traumatic brain injury. Ed. Z.I. Geimanovich, Ed. psychoneurol. inst., Kharkov, 1947, volume XXI (69), 243 p., ill.].

Surgical treatment of wounds involves the removal of metal FB from brain wounds and requires the presence of special equipment. The need to have a magnet pin in the equipment is found in the manuals on neurotraumatology [Manual on neurotraumatology. Part II. Spinal trauma, damage to peripheral nerves, military field neurosurgery. Ed. A.I. Arutyunova. M., Medicine, 1980, 392 pp., ill.], which are used in various modifications (Fig. 1) to this day.

However, despite their function, pin magnets have a design that limits the view of the wound and manipulation in its depth due to the straight shape of the handle, and in some cases they are too massive.

Currently, removal of metallic FBs deep in the brain is carried out under optical magnification (usually an operating microscope) along a narrow wound channel or along another trajectory, planned on the basis of a preoperative examination, through an intact area of the brain. When approaching the desired object along a narrow operating corridor, tweezers with different jaw tips, including clawed (rounded) shapes, are used to capture and remove IT. To implement this technique, it is necessary to spread the ends of the tweezers wider than the visible edges of the IT, which can lead to additional trauma to the brain substance, which is especially unacceptable when working near functionally significant areas, pathways and vessels, damage to which leads to permanent dysfunction of the central nervous system. In some cases, FBs deep in the wound cannot be detected with the naked eye and cannot be removed.

In order to reduce the trauma of removing foreign bodies using a magnet, standard bayonet-shaped tweezers with thin jaw tips are used, which grasp a cylindrical magnet of different diameters (Fig. 2). However, this “tweezers-magnet” design does not allow the magnet to be positioned coaxially with the thin jaws of the tweezers and the magnet deviates from a straight line up to 90°, limits manipulation in a narrow wound corridor, can slip out of the tips of the jaws and even be lost.

To avoid spreading the ends of the jaws when grasping the FB, to minimize intraoperative unintentional iatrogenic damage to the brain substance, and to rigidly coaxially hold a cylindrical neodymium magnet, tweezers have been developed to achieve the goal of surgical intervention in the wounded with the possibility of industrially manufacturing tweezers of various lengths with curved tips of different diameters.

The purpose of the utility model is to develop a line of bayonet-shaped microsurgical tweezers with the ability to rigidly grip a cylindrical neodymium magnet of different diameters for working at different depths in a narrow brain wound.

The solution to this problem is ensured by the fact that the bayonet form of tweezers made of stainless medical steel with an angle of inclination of the working part (branches) of 15° relative to the handle with transverse notches for tactile sensations of the instrument, which allows not to limit the view of the surgical field through the eyepieces of the microscope, the ends of the jaws are formed concave shape, with a radius of curvature corresponding to the diameter of the neodymium cylindrical magnet used. The stable position of the magnet is facilitated by the internal curvature of the ends of the jaws with internal transverse notches and the ferromagnetic composition of the tweezers, which ensures the attraction of the magnet to the jaws, which prevents their spontaneous opening with subsequent loss of the magnet. The length of the working part of the tweezers is 55 mm, 75 mm, 95 mm and 115 mm, which allows, depending on the depth of the wound, to use a tool of the required length and ensure ease of work. Marks placed on the upper and outer surfaces of the jaws with a step of 10 mm allow you to navigate in the depth of immersion along the wound channel, correlating the surgeon’s actions with preoperative images.

Currently, there is no industrial production of the proposed tweezers model.

Technical result - a new line of microsurgical tweezers has been proposed, allowing them to be used in conjunction with a rigidly held cylindrical magnet of different diameters coaxially with the jaws during the removal of ferromagnetic ITs.

The use of the developed tweezers in combination with a cylindrical neodymium magnet makes it universal for working in deep brain wounds when extracting metal FB, including other organs and systems, at all stages of providing specialized medical care in wartime conditions, as well as in medical institutions civil health care during surgical interventions in the wounded.

The utility model is illustrated by figures, where

figure 1 - pin magnet;

figure 2 - standard bayonet-shaped tweezers with thin jaw tips;

in Fig. 3A and Fig. 3B - the appearance of the tweezers in the lateral projection of a bayonet shape with an angle of the working part in relation to the handle of 15°, the ends of the jaws are concave, marks are placed on the upper surfaces of the jaws along the length every 10 mm;

Fig. 3B is a cross section of the rounded ends of the tweezers together with a round magnet, the radius (R) of the cylindrical shape of the magnet corresponds to the internal radius of curvature of the ends of the tweezers to fit them tightly to each other;

figure 4 - CT results of the first patient;

Fig. 5 – CT results of the second patient.

Fig. 3A and Fig. 3B show the appearance of the tweezers, consisting of: 1 – ends of concave-shaped jaws, 2 – marks on the upper and side surfaces of the jaws along the entire length every 10 mm, 3 – tweezer handles with transverse notches, 4 – 15° inclination angle of the working part (5) relative to the handle (3), 6 – radius of the cylindrical magnet.

Below are several clinical examples illustrating the possibilities of using the neodymium magnet-tweezers design to extract foreign metal bodies with different depths of the brain wound. The length range of the working part of the tweezers is determined as average depending on the anatomical dimensions of the skull.

Clinical example No. 1 is illustrated in Fig. 4, patient An.

A computed tomography (CT) scan revealed a foreign metal body (Fig. 4A, Fig. 4B – 7), located in the substance of the brain at the midline of the head with an entrance hole (Fig. 4B, Fig. 4D, Fig. 4D, Fig. 4E – 8) of a wounding projectile in the right temporal region and the course of the wound canal from bottom to top and from right to left (Fig. 4B). Due to the nature of the wound, the presence of a verified aneurysm of the cortical branch of the right middle cerebral artery (Fig. 4E - 10), a decision was made to remove the foreign metal body through the wound channel instead of convexital access to the FB, and clipping the aneurysm to prevent aneurysmal intracerebral hemorrhage, and remove the bone fragment (Fig.4D and Fig.4E – 9). As can be seen in Fig. 4B, the distance from the surface of the cerebral cortex to the IT is very large and exceeds 10 cm. During the surgical intervention, resection craniotomy was performed in the right temporal region. Under the optical magnification of an operating microscope, the aneurysm was visualized and clipped. Along the wound channel, access was made to the FB, which is difficult to recognize at a depth of more than 10 cm, and capture and extraction with tweezers is impossible due to the high risk of damage to nearby vascular structures and brain matter. To remove FB, a neodymium magnet was used, brought to the bottom of the wound channel using tweezers. Plastic surgery of the trepanation defect was performed using a titanium mesh plate. Control CT images are presented as a 3D CT reconstruction in Fig. 4G and Fig. 4H, in which one can note the presence of a clip (Fig. 4G - 11) applied to the aneurysm, and the absence of IT removed through the wound channel (there are no signs of trepanation on the cranial vault), a titanium mesh plate at the site of the trepanation defect (Fig. .4G and fig.4Z – 12).

Clinical example No. 2 is illustrated in Fig. 5, patient R-v. At the stage of specialized medical care, primary surgical treatment of the wound was performed without removing the IT (metal) from the depths of the brain wound. In the neurosurgery clinic, the patient was examined, on preoperative CT images (Fig. 5A, Fig. 5B, Fig. 5B) a metal fragment is identified (Fig. 5A, Fig. 5B - 7), located in the projection of the midbrain peduncle on the right, the convolution is lysing hematomas along the wound channel (Fig. 5B - 13), the dimensions (Fig. 5B) of the frontal bone defect on the right after resection trepanation performed during the primary surgical treatment of the wound and the distance from the surface of the brain to the IT are indicated (Fig. 5A). In order to prevent delayed infectious complications due to penetrating brain injury, based on a comprehensive preoperative examination, a decision was made to perform repeated surgical treatment of the wound, aimed at sanitizing the wound channel from blood clots, removing FB, and cranioplasty. Through the wound channel, with a total length of 7 cm from the surface of the brain to the fragment, access to the intended target was achieved. The wound channel has been sanitized. Due to the deep location of the IT, free manipulation of microsurgical instruments, including tweezers for grasping them, is unacceptable due to the high probability of additional trauma to a functionally significant area of the brain. A narrow (d=5mm) neodymium magnet was used, inserted using tweezers to the bottom of the wound canal. IT removed. The result of the surgical intervention is presented on a postoperative CT scan - Fig. 5D, Fig. 5D, Fig. 5E: 12 - titanium mesh plate, 15 - site of a previously located foreign metal body, 16 - absence of blood clots in the wound channel.

Claims (1)

Tweezers for removing foreign metal magnetic bodies from a narrow and deep wound of the brain with a cylindrical neodymium magnet clamped between the ends of the jaws, characterized in that the tweezers have a bayonet shape and are made of stainless medical steel with an angle of inclination of the jaws of 15° relative to the handle with transverse notches, wherein the ends of the jaws are made with an internal radius of curvature corresponding to the radius of the cylindrical shape of the neodymium magnet to fit them tightly to each other, while marks are applied to the upper and outer surfaces of the jaws in increments of 10 mm, and the length of the working part of the tweezers is 55 mm, 75 mm, 95 mm and 115 mm depending on the depth of the wound.