RU2801894C1 - Method of marking skull bones - Google Patents

Abstract

FIELD: medicine; neurosurgery.

SUBSTANCE: patient is positioned on the operating table, the head is fixed in the required position. Landmarks are marked for performing trepanation on the skin using a sterile medical dye. After the initial marking of the landmarks, a sterile dye is drawn into the syringe and injected into the periosteum of the skull through points on the skin related to the marked landmarks. After cutting and retracting the scalp, dye spots on the periosteum are visualized. In places where the colored areas of the periosteum come into contact with the bones of the skull, landmarks are marked for performing trepanation.

EFFECT: use of the invention makes it possible to provide a simple and quick transfer of landmarks from the skin to the bones of the skull for performing trepanation.

4 cl, 7 dwg

Description

The field of technology to which the invention belongs

The invention relates to neurosurgery, and in particular to methods for marking the bones of the skull.

State of the art

One of the important stages of the surgical operation is the planning and execution of access to structures of interest in such a way as to make manipulations on them as simple and effective as possible.

In cranial neurosurgery, access includes a scalp incision, skeletonization and trepanation of the skull bones, opening of the dura mater, and approach to the pathological focus. An important role is played by the accuracy of planning cuts and cuts at each level, so that one layer of tissue does not interfere with work on another.

At the level of the skull bones, a frequent problem is the displacement of the boundaries of the trepanation window, when the projection of the pathological focus (for example, a tumor) partially or even completely does not coincide with the trepanation zone. This forces the surgeon to excessively dissect the hard shell, which subsequently complicates its suturing and reduces the tightness of the suture, increasing the risk of liquorrhea. In the process of approaching the focus, the surgeon has to work at an uncomfortable angle and in a narrower corridor, in conditions of limited visibility. Sometimes it is necessary to expand the trepanation window with nippers or burs, which creates a cosmetic defect and may require cranioplasty, either immediate or delayed, using foreign materials.

One of the sources of this problem is the imperfection of intraoperative marking technology. This usually happens in the following way.

Before starting the operation, the surgeon studies neuroimaging data (MPT, CT, etc.) for the location of the pathological focus (for example, a tumor) relative to visually or palpation accessible anatomical landmarks: midline, cranial sutures, bridge of the nose, external auditory canal, etc. After immersion in anesthesia, the patient is positioned on the operating table and his head is fixed in the required position. Guided by the previously obtained information, the surgeon determines the selected landmarks and with their help calculates the location of the projection of the pathological focus on the skin. This area is marked with a sterile medical dye, such as fucorcin or brilliant green. Then the borders of the trepanation window and the scalp incision line are marked.

The disadvantage of this method is that the calculated and marked landmarks remain on the skin and are not visible after the scalp flap is retracted. In addition, before the skin incision, the surgical field is treated with an antiseptic solution, which often washes away the dye. An opaque sterile underwear and an incise film are glued onto the skin around the incision line, which hide the markings, as well as those anatomical landmarks with respect to which it was calculated.

After retracting the scalp flap, the surgeon opens the bones of the skull, which contain a number of landmarks: cranial sutures (coronary, sagittal, lambdoid, etc.), superior temporal line, processes and protrusions of the external base of the skull (zygomatic arch, external occipital protrusion, etc.) . However, these formations are not always included in the access zone. Even if one of the borders of the planned trepanation window is located close to these landmarks, the remaining borders may be far away and are often covered by an overhanging scalp flap, especially if it is thickened or economically cut. In addition, the seams may not be expressed, and the protrusions may be smoothed out.

Thus, the pathological focus and the trepanation zone can be projected onto the skin and marked with a dye, however, at the stage of exposing the bones of the skull, many landmarks are lost, which creates conditions for malposition of the trepanation window.

A known method of projection of the pathological focus - frameless neuronavigation [1], which includes the combination of the patient's head, its computer model, built on the basis of CT and MRI images, as well as a special sterile pointer in a single coordinate system of the navigation station. When touching the tip of the pointer to the bones of the skull, skin, etc. the surgeon can see on the screen of the station the location of the touch point in relation to the pathological focus and other structures of the head. Based on this, intraoperative marking is carried out, including the bones of the skull.

The disadvantage of this method is that the equipment for frameless neuronavigation is bulky, expensive, difficult to handle and repair. Its installation and configuration require time and advanced computer skills. Not all surgical centers have this equipment.

Disclosure of invention

The technical result of the proposed invention is to provide a simple and quick transfer of landmarks for performing trepanation from the skin to the skull bones.

To achieve this technical result, a method has been developed that includes positioning the patient on the operating table, fixing the head in the required position, marking landmarks for performing trepanation on the skin using a sterile medical dye, scalp incision and performing craniotomy, characterized in that after marking the landmarks, syringe with a sterile dye and inject it into the periosteum of the skull through points on the skin related to marked landmarks; after cutting and retracting the scalp visualize stains of the dye on the periosteum; in places of contact of the colored areas of the periosteum with the bones of the skull, markings are made for performing trepanation.

Fukortsin can be used to mark the skin.

The patient's venous blood can be used as a sterile dye to mark the skull bones.

Marking landmarks for trepanation can be performed using a monopolar electrode.

The claimed technical result is ensured due to the fact that the periosteum at the injection site deposits the dye, which is clearly visible after raising the scalp flap. An example of a suitable dye is venous autologous blood, a genetically homogeneous, biocompatible and readily available material that is processed in the body without consequences after surgery.

If the initial marking of landmarks on the skin is done correctly, then the transfer of the corresponding points from the skin to the bones of the skull contributes to the effective implementation of trepanation within the planned boundaries. This prevents the surgeon from spending time, effort and materials to correct his own mistakes, usually made at this stage.

The proposed method can be carried out quickly and easily, without the use of additional equipment.

Description of the Drawings FIG. 1. Schematic representation of a fixed patient's head. A rectangular trepanation is planned, mainly in the right parasagittal region, with exposure of the superior sagittal sinus. Relevant landmarks, tumor projection, trepanation contours and scalp incision line are marked with dye on the skin.

Fig. 2. Marking the bones of the skull by injecting a dye into the periosteum. The dye was introduced at four points corresponding to the tops of the trepanation zone.

Fig. 3. Draperies. The head was treated with an antiseptic and covered with sterile linen and incise film. The cut line of the scalp is visible through the film.

Fig. 4. Incision and detachment of the scalp. The aponeurotic skin flap is retracted, and hemostatic clips are placed on its edges. Landmarks previously marked on the skin are not visible at this stage. Dye spots are visualized in the periosteum.

Fig. 5. Incision and detachment of the periosteum. The periosteal flap is retracted. Notches were made at the points of contact of the colored points of the periosteum with the bones of the skull, then they were combined into the contour of the trepanation window.

Fig. 6. Trepanation of the skull. A craniotomy was performed along the marked contour, the bone flap was raised and temporarily removed. The superior sagittal sinus is exposed.

Fig. 7. Opening of the dura mater. The dural flap was retracted medially. A parasagittal meningioma is visible in the center of the trepanation, its edges are equidistant from the contour of the trepanation window.

Designations:

1 - Head

2 - Projection of the coronal suture on the skin

3 - Middle line

4 - Bregma projection (crossing of the sagittal and coronal suture)

5 - Projection of the tumor on the skin

6 - Projection of the contour of the trepanation window on the skin

7 - Scalp incision line

8 - Syringe

9 - Sterile dye

10 - Drapery

11 - Aponeurosis (inner surface of the skin-aponeurotic flap)

12 - Hemostatic skin clips

13 - Periosteum

14 - Dye spots in the periosteum

15 - Sagittal suture

16 - Contour of the trepanation window (marking on the bones)

17 - Trepanation window

18 - Dura mater

19 - Superior sagittal sinus

20 - Brain

21 - Tumor

Implementation of the invention

The method of marking the bones of the skull includes positioning the patient on the operating table, fixing the head in the required position, marking landmarks for performing trepanation on the skin using a sterile medical dye, incision of the scalp and performing trepanation of the skull. In this case, after the initial marking of the landmarks, a sterile dye is drawn into the syringe and injected into the periosteum of the skull through points on the skin related to the marked landmarks. After cutting and retracting the scalp, dye spots on the periosteum are visualized. In places where the colored areas of the periosteum come into contact with the bones of the skull, landmarks are marked for performing trepanation.

The proposed method can be used when performing neurosurgical operations in patients with various intracranial focal pathologies: extra- and intracerebral tumors, arteriovenous malformations, cavernomas, focal cortical dysplasia, etc.

To perform the method, it is necessary that the skull bones be preserved in the area of the planned trepanation. In the presence of a bone (postoperative) defect, there is no need for marking; in addition, the injection in this case can be dangerous in view of the risk of damage to the substance of the brain and blood vessels supplying it.

Before starting the operation, the surgeon carefully studies the neuroimaging data (MPT, CT, etc.) and calculates the location of the projection of the pathological focus on the skin relative to visually or palpation accessible anatomical landmarks (midline, cranial sutures, etc.). Taking into account the calculations performed, they draw up a diagram of the trepanation zone indicating its shape, location and size. In this case, it is necessary to plan an indentation inward from the edge of the trepanation window for a comfortable incision and suturing of the dura mater, as well as, if necessary, plasty of the dural defect.

After entering the operating room, the patient is immersed in anesthesia, positioned on the operating table, and his head is fixed in the required position with the help of a head holder. Hair (if any) is treated with an antiseptic solution, combed and distributed in such a way that it does not interfere with the search for landmarks and skin marking.

Next, relevant anatomical landmarks are determined and marks are placed in the places of their projection on the skin with a sterile medical dye (fucorcin, brilliant green, etc.). Important landmarks include: the midline, the upper edge of the frontal sinus, the upper edge of the pyramid of the temporal bone, bregma (the junction of the coronary and sagittal sutures), lambda (the junction of the lambdoid and sagittal sutures), stephanion (the junction of the coronary suture and the superior temporal line), etc. .

The points belonging to the trepanation zone are also marked with a dye: you can mark its center (in the case of a round shape) or vertices (if the shape is square, triangular, etc.).

The scalp incision line is marked: linear, arcuate, S-shaped, etc. The hair around the incision line is shaved, before or after its marking.

Next, a sterile dye is drawn into a disposable syringe with a volume of 5-10 ml for marking the bones of the skull. A synthetic dye can be used, such as 1% aqueous methylene blue. It is also possible to use the patient's venous blood, which the anesthetist draws from a peripheral or central catheter under aseptic conditions. Marking usually requires up to 1 ml of dye per marking point. The syringe needle can have a diameter of 21-23G: 0.6, 0.7 or 0.8 mm - with a blue, black or green pavilion, respectively.

The surgeon treats the scalp with an antiseptic in the marking area and injects the dye into the periosteum of the skull through points on the skin related to the marked landmarks. The syringe needle must be inserted perpendicular to the skin surface so that no angular displacement occurs, until the tip of the needle is felt to touch the bone. Up to 1 ml of dye is injected into each marking point.

The time from marking the landmarks on the skin to the introduction of the dye into the periosteum is about 5 minutes.

The standard processing and draping of the surgical field is carried out using sterile underwear and incise films.

Under aseptic conditions, a scalp incision is performed, hemostasis of the incision edges, and the soft tissue flap is retracted using a retractor, rubber bands, springy hooks, etc. The incision is made up to the periosteum, while the skin-aponeurotic flap is peeled off from it, constantly pulling with a hook, until colored spots appear in the field of view - points of dye accumulation. It is necessary to expose all points of the intended contour.

Next, the periosteum is cut and peeled off from the bone, while at the points of contact of the dye spots with the bone, marks are made using a monopolar electrode. The periosteal flap on the feeding leg is taken aside and, if necessary, fixed to the skin-aponeurotic flap with a ligature. The marks obtained on the bone are connected into one contour, bordering the planned trepanation window.

Sometimes it is required to perform a scalp incision immediately to the bone with simultaneous detachment of all layers of tissues, including the periosteum. In this case, marks on the bone are made in the places of its contact with the stains of the dye as the soft tissue flap is gradually detached, while the periosteum remains on its inner side.

The contour of the trepanation window outlined on the skull bones is visualized. Burr holes are applied using a perforator, bur or brace. Along the perimeter of the holes, the dura mater is peeled off from the inner bone plate using a bone spoon or dissector. Trepanation of the skull bones is performed along the intended boundaries using a craniotomy, a wire saw, etc. The mobilized bone flap is lifted using an elevator.

The dura mater is opened with a scalpel and dural scissors. It is necessary to remember about the gap between the edge of the shell incision and the edge of the bone window, which is necessary for comfortable suturing or plasty of the shell. It must be at least 5 mm.

After completion of the access and the main stage of the operation, the final hemostasis is performed and, if necessary, duroplasty. To do this, you can use a fragment from a previously prepared periosteal apron. At this stage, dye spots in the periosteum help to quickly and easily find a flap of the required shape and size.

The wound is then closed using the standard technique.

List of used literature

1. Kim S, Kim KN. How to use neuronavigation for the brain. Journal of the Korean Society of Stereotactic and Functional Neurosurgery 2021;17(2): 126-132. doi:10.52662/jksfh.2021.00080.

Claims (4)

1. A method for marking the bones of the skull, including positioning the patient on the operating table, fixing the head in the required position, marking landmarks for performing trepanation on the skin using a sterile medical dye, incision of the scalp and performing trepanation of the skull, characterized in that, after marking the landmarks, they are drawn into a syringe sterile dye and introduce it into the periosteum of the skull through points on the skin related to marked landmarks; after cutting and retracting the scalp visualize stains of the dye on the periosteum; in places of contact of the colored areas of the periosteum with the bones of the skull, markings are made for performing trepanation. 2. The method according to p. 1, characterized in that fucorcin is used to mark the skin. 3. The method according to p. 1, characterized in that for marking the bones of the skull, venous blood of the patient is used as a sterile dye. 4. The method according to p. 1, characterized in that the marking of landmarks for performing trepanation is performed using a monopolar electrode.