Surgical spatula

Abstract

A manual surgical spatula is described, manufactured as a single, substantially flattened piece. When not in use, the spatula is arched; however, when in use, as the surgeon moves human tissue with the spatula, the spatula is susceptible to elastic bending and tends to flatten, i.e., straighten into a flattened configuration, in response to the force the patient's tissue applies to the end of the spatula. The spatula is equipped with one or more tactile and / or visual indicators aligned along the longitudinal axis, each indicator indicating a gripping position that uniquely corresponds to a bending load value of the spatula. This arrangement makes it possible to manufacture the spatula in such a way that when gripped at a particular tactile and / or visual indicator, flattening of the spatula occurs in response to a pressure value uniquely corresponding to that indicator. This means that the surgeon has objective and quantitative feedback of the pressure applied to the tissue. The spatula may also be equipped with a light source, in which case the light propagates through the material of the spatula like an optical fiber; thereby making it possible to illuminate the pulled tissue.

Description

Technical Field

[0001] The present invention relates to a surgical spatula, and more particularly to a surgical spatula for vascularized tissue.

Background Art

[0002] In the surgical field, the use of instruments called retractors, dilators or dissectors is known, and they have the function of moving the tissues of the patient undergoing surgery at the surgical site and providing access to, for example, a tumor to be removed or a tissue to be examined for the surgeon.

[0003] Among the most widely used retractors, there is a "spatula" which, like all surgical instruments, is subject to certification and sales approval obligations.

[0004] Conventional manual spatulas are manufactured like medical stainless steel foils, i.e., elongated elements with a very small thickness compared to their length and width. The spatula is flat with a rectangular cross-section or has a wavy or spoon shape with a U-shaped cross-section.

[0005] The manual spatula is held by the surgeon with one hand and inserted into the surgical site to hold and push aside the tissue that needs to be temporarily moved to access the underlying area of interest.

[0006] Manual spatulas are used in various surgical procedures, but are particularly important in craniotomy, where the brain tissue is very delicate and it is necessary to temporarily move a part of the brain to access the area of interest. In fact, if the pressure applied to the brain tissue, i.e., the brain retraction pressure (BRP), becomes excessive, it can easily cause damage to the patient. Especially in skull base surgery, the tumor lesion may be located very deep in a dangerous brain area, and in such cases, it is necessary to use one or more surgical spatulas to ensure sufficient surgical space, but this often poses a risk of damage to important brain structures and brain parenchyma.

[0007] A further drawback is that the edges of conventional metal manual spatulas are known to be particularly dangerous, as the pressure applied by the spatula to the brain parenchyma tends to concentrate at the edges. Additionally, when manipulating the spatula, surgeons often perform displacements involving rotation in addition to anterior-posterior movement, resulting in a further localized increase in BRP at the edges.

[0008] Possible brain traction injuries include contusions, hematomas, hemorrhages, and nerve damage, which set the pattern for direct iatrogenic injury or include parenchymal ischemic attacks due to metabolic hemodynamic changes. All of these complications affect the favorable outcome of surgical treatment and can therefore invalidate the favorable outcome of the patient's surgical procedure. The literature has shown that the incidence of complications from surgical traction is as high as 45%, when postoperative radiography is considered as an injury detector. (Recinos PF, Raza SM, Jallo GI, Recinos VR. Use of minimally invasive tubular traction systems for deep tumors in pediatric patients: technical notes. J. Neurosurg Pediatr. 2011;7(5):516-521. Doi:10.3171 / 2011.2.PEDS10515. Serarslan Y, Cokluk C, Aydin K, Iyigun O. Soft microballoon pads for brain traction for nerve tissue protection. Minim Invasive Neurosurg MIN. 2006;49(6):373-375. doi:10.1055 / s-2006-955067. Singh L, Agrawal N. Stitch retractor - a simple technique for brain traction. World Neurosurg. 2010;73(2):123-127. doi:10.1016 / j.surneu.2009.01.031).

[0009] The threshold for BRP pressure applied to tissue that exceeds the threshold at which tissue damage occurs is not universally recognized and depends on the nature of the tissue, its condition, and the duration of application, i.e., the duration of traction.

[0010] For example, in the following paper: - Rosenφrn J, Diemer NH. - Decrease in local cerebral blood flow during cerebral traction pressure loading in rats. Journal Neurosurg. 1982;56(6):826-829. doi:10.3171 / jns.1982.56.6.0826; - Rosenφrn J, Diemer NH. Effects of intermittent and paired continuous cerebral traction pressure on local cerebral blood flow and neuropathology in rats. Acta Neurochir (Wien). 1988;93(1-2):13-17. doi:10.1007 / BF01409896. The authors explain that maintaining a BRP pressure of 30-40 mm mercury columns for 15 minutes results in a significant decrease in local cerebral blood flow (rCBF) and causes brain damage, while performing the same experiment with intermittent application of a BRP pressure of 40 mm mercury columns for 5-7 consecutive minutes at 1-minute intervals, no damage is detected.

[0011] In general, studies suggest that intermittent application of BRP pressure is desirable to avoid damaging human brain tissue, provided the maximum pressure is approximately 40 millimeters of mercury and the application time does not exceed 7 minutes. If it is necessary to apply PRC pressure at longer time intervals, such as 10 consecutive minutes, the PRC pressure value must necessarily be lower before each interval, for example, 30 millimeters of mercury.

[0012] However, these are not universally applicable time intervals, and in practice, it is left to the surgeon to evaluate the intensity and duration of intermittent BRP pressure application based on the need for the surgical procedure being performed at that time.

[0013] Furthermore, it is known that if traction damage has already occurred, some of the damage can be immediately visualized during surgery. However, if any damage can be detected during surgery, the surgeon can adjust the applied pressure. On the other hand, there is another problem: damage that the surgeon cannot confirm with the naked eye or microscopically during surgery. This is precisely damage to the brain parenchyma, which cannot be immediately detected during surgery and can only be identified retrospectively by postoperative CT or MRI radiological examinations, that is, only after the surgery is completed. Therefore, the aforementioned damage is more dangerous because the surgeon cannot detect it during surgery and thus cannot adjust the pressure applied to the brain.

[0014] The severity of the above can be even more pronounced in children. This is because the available space within a child's skull is more limited than that of an adult, requiring more pressure to be applied to the brain tissue in order to move it, thus increasing the likelihood of errors.

[0015] US6,093,145 describes a surgical spatula for brain surgery comprising an internal metal core having a rectangular cross-section covered with a soft, elastically deformable material with flexible wings and rounded edges. The covering material is preferably silicone. This solution makes it possible to achieve a spatula with a central section having a hardness between 50 and 70 Shore and an edge hardness between 20 and 40 Shore, and is therefore far less dangerous than the edges of conventional uncoated spatulas.

[0016] JP2005323793A describes a spatula constrained to a cylindrical grip in a telescopic manner, which also functions as a container for surgical fluids released during surgery and as a sheath for guiding surgical instruments. This solution minimizes the length of the spatula's edge that comes into contact with patient tissue at any given time, with only the edge of the portion of the spatula extended from the grip coming into contact with the tissue.

[0017] As mentioned above, the effectiveness of manual spatulas basically depends on the surgeon's sense and precision; that is, if an error occurs in tissue traction (compression) using a manual spatula, exceeding the BRP threshold, there is no way to correct or mitigate it. Conventional manual surgical spatulas essentially transmit the pressure applied by the surgeon directly to the tissue.

[0018] To provide feedback to surgeons, a sensor-equipped spatula has recently been proposed, namely one pressure sensor and a corresponding electronic control circuit PCB; the sensor is positioned at the end of the spatula intended to be inserted between tissues and generates an electrical signal indicating the BRP pressure applied to the sensor (by the patient's tissue). The control circuit receives and processes the signal generated by the pressure sensor and emits an acoustic and / or optical signal when a threshold is exceeded. In this way, the surgeon has feedback on the PRC pressure applied to the spatula and can adapt it to the current conditions so as not to exceed the threshold.

[0019] Spatulas equipped with pressure sensors are described, for example, in JP6856198, CN204181665(U), CN115227300A and CN114129206A.

[0020] Therefore, on the one hand, manual surgical spatulas are easy and inexpensive to manufacture but do not provide feedback to the surgeon and leave no room for human error, while on the other hand, sensor-equipped surgical spatulas provide feedback but are more complex, and therefore difficult and expensive to manufacture, and generally occupy a larger area than conventional surgical spatulas due to the fact that they house sensors, control circuits and associated connections.

[0021] US2007 / 208226 describes a single-piece manual surgical spatula extending along a longitudinal axis between a first end and a second surgical end, with a grip provided at the first end. The thickness of the surgical spatula is negligible compared to its length and is approximately equal to its width, as a portion of the spatula has a substantially square cross-section. The spatula is manufactured from polycarbonate and can be functionally coupled to an LED light source at the grip. Light propagates through the polycarbonate from the LED light source to the opposite end of the surgical spatula. The flattened portion of the surgical spatula near the surgical end has a faceted surface shaped like a Fresnel lens, which serves to guide the light inside the spatula outward and further forward towards the surgical end, like a headlight. This faceted surface guides the light generated by the LED light source during use of the spatula, allowing it to illuminate the tissue.

[0022] GB1242374 describes a spatula with a substantially rigid surgical end and multiple holes. The holes may be harmful to the brain parenchyma, they may cause microtrauma to tissue, and since the tissue is soft rather than solid, it can penetrate the holes and the tissue may be damaged.

[0023] US3,888,117 describes a rigid surgical spatula with a stainless steel core and a pressure sensor. The sensor then includes several beads inserted into appropriate holes arranged at a constant pitch along the spatula. The beads are enclosed in an insulating housing and, by moving within their respective holes, can come into contact with a conductive tape inside the spatula, thus closing an electrical circuit and enabling the generation of a signal. The beads are electrically connected to a single longitudinal wire, and for this reason, they cannot be selectively pulled back into their respective holes.

[0024] US2018 / 317902 describes a flexible surgical spatula equipped with multiple light sources such as LEDs driven by batteries arranged at a constant pitch along the spatula. The spatula has a suction tube located on the side of the surgical spatula and can be connected to an external suction source. The light sources illuminate the surgical site and have the function of providing the surgeon with an indication of the depth at which the surgical spatula is pressed between the patient's tissues.

Summary of the Invention

[0025] The underlying technical problem of the present invention is, therefore, to provide a manual surgical spatula, i.e., a manual surgical spatula without electronic sensors and circuits, which has a simple structure, is reliable, ergonomic, inexpensive, and can overcome the limitations of conventional solutions, and by limiting or completely preventing exceeding the threshold pressure at which the patient's vascularized tissue is damaged during traction (spatulation), i.e., to provide a spatula that provides appropriate feedback to the surgeon.

[0026] Yet another object of the present invention is to provide a surgical spatula for brain surgery, i.e., for adult and pediatric craniotomies, which does not prevent the surgeon from seeing the spatulated tissue.

[0027] Therefore, the present invention relates to a surgical spatula according to claim 1.

[0028] The surgical spatula is of the manual type, i.e., of a type without any electronic sensors and their respective control circuits, and is manufactured as a single unit, i.e., as a single element rather than an assembly of assembled components.

[0029] The spatula extends along the vertical axis between a first end and a second end, and has a substantially thin plate-like or flat shape, which means that the thickness of the spatula is smaller than its length and width and is preferably negligible. The second end is the surgical end and is intended to come into contact with the patient's tissue during a surgical procedure. Preferably, the thickness of the spatula is negligible compared to its length and width.

[0030] The spatula can be held by a surgeon with one hand between the first end and the second end.

[0031] The spatula is arched, i.e., concave, in its normal state, i.e., when stationary and not in use; however, when in use, when the surgeon uses the spatula to move human tissue, the spatula is elastically flexible and easily flattens, i.e., transforms into a straight-line shape, under the pressure (load) exerted by the patient's tissue on the tip of the spatula.

[0032] Thus, the spatula flexibly transforms from a concave or arched configuration to a flat configuration corresponding to reaching a pressure threshold value in response to the stress applied by the surgeon during spatula operation. Further, if bending continues and the curvature of the spatula reverses beyond the flat configuration, the user recognizes that the spatula has exceeded the threshold value.

[0033] The spatula comprises one or more tactile and / or visual indicators arranged along its longitudinal axis, and each indicator indicates a gripping position that uniquely corresponds to an exact value of the bending load of the spatula, and this bending load value is a quantitatively preset, measured and measurable pre-set value set in advance by the manufacturer and common to all spatulas produced.

[0034] The bending load value of the spatula, and the value corresponding to each tactile and / or visual indicator, is provided together with documentation regarding the method of operating the spatula, such as an instruction manual or a conformity / approval certificate, and can also be described directly on the surgical spatula.

[0035] Advantageously, surgical spatulas can be certified by the manufacturer to provide a precise and unique match between each tactile and / or visual indicator and its corresponding bending load value. This allows surgeons to always maintain control over the maximum pressure applied to tissue during surgical procedures.

[0036] Simply put, tactile and / or visual indicators constitute a stepped scale of the bending load of the surgical spatula, i.e., a measure of the bending load the surgical spatula exhibits relative to straightening; straightening of the spatula means reaching the corresponding maximum pressure value when grasped at its precise tactile / visual indicator position.

[0037] This configuration allows the spatula to be manufactured so that, when grasped at a specific tactile and / or visual indicator site, the spatula flattens to a pressure value uniquely corresponding to that indicator. This means that when the surgeon grips the spatula at the tactile and / or visual indicator location, pressure is applied to the patient's tissue through the second end of the spatula, particularly through its pre-set contact area; this pressure is below the corresponding threshold at which the spatula becomes completely straightened (flattened).

[0038] The pre-defined contact area serves as the working area for applying pressure to the tissue, acting as an alternative to the edge of the spatula. In practice, areas other than this contact area are not used for several main reasons. Firstly, using the edge of the spatula can easily damage the brain parenchyma and cause undesirable rotation of the spatula. Furthermore, the brain inherently has a curved shape, and therefore, when the brain must be spatulamed to reach deep tissues during surgery, ensuring the entire contact area of ​​the spatula is in close contact with the brain surface provides maximum conformity to the brain's shape and optimal maneuverability for the surgeon.

[0039] Tactile and / or visual indicators, therefore, allow for the calibration of pressure applied to the patient's tissues according to quantitative values ​​rather than qualitative values, which is a clear benefit to favorable outcomes of surgical procedures.

[0040] Therefore, the spatula provides the surgeon with passive but immediate feedback. Unlike sensor-equipped solutions that emit audible or visual alarm signals, the spatula according to the present invention provides the surgeon with purely mechanical / visual feedback. That is, when the surgeon applies enough pressure to the patient's tissue through the contact area of ​​the second end to straighten, or flatten, the spatula, the surgeon recognizes that a pressure threshold corresponding to a specific tactile and / or visual indicator is reached where the spatula is currently being grasped. Furthermore, if the pressure applied exceeds the specific bending load value indicated by the straightening of the spatula, the surgeon understands that the pressure being applied to the patient's brain tissue exceeds the value corresponding to the specific indicator being grasped, and also realizes that further increasing the pressure could damage the patient's brain tissue. In other words, the surgeon is always in control of the pressure being applied.

[0041] Clearly, it is possible to manufacture a spatula with a single tactile and / or visual indicator, but preferably the spatula is manufactured with multiple indicators.

[0042] For a single tactile and / or visual indicator, the user, i.e., the surgeon, has three grasping positions available: one on the indicator, one immediately in front of the indicator, and one immediately behind the indicator. Thus, this configuration makes it possible to have three thresholds of (maximum) pressure applied to the tissue when the spatula is straightened.

[0043] Clearly, when the spatula is gripped in the intermediate portion located between two consecutive tactile and / or visual indicators, the feedback provided to the surgeon corresponds to a pressure value that lies midway between two thresholds uniquely corresponding to these two indicators.

[0044] Preferably, there are four tactile and / or visual indicators, corresponding to the maximum pressure values ​​applied (on the patient's tissue) at one end of the spatula, equal to 15 mm of mercury, 22 mm of mercury, 30 mm of mercury, and 45 mm of mercury, respectively, and equal to 1999.83 Pascals, 2933.084 Pascals, 3999.66 Pascals, and 5999.49 Pascals.

[0045] A surgical spatula according to a preferred embodiment is typically arched, that is, when not in use, extends along an arc of a circumference defined by radius R, for example, equal to 150-200 millimeters, and with a central angle equal to, for example, 50-60 degrees. Considering this geometric configuration, the angular pitch between tactile and / or visual indicators, calculated in relation to the central angle in a stationary state for an arched spatula, corresponds to 4-6 degrees. Thus, with this angular pitch, the distance between tactile and / or visual indicators is equal to approximately 5 millimeters.

[0046] Preferably, the first tactile and / or visual indicator is at an angle of 22 degrees center with respect to the first end of the spatula, and the fourth tactile and / or visual indicator is at an angle of 36 degrees center with respect to the first end of the spatula.

[0047] In a preferred embodiment, tactile and / or visual indicators are bosses protruding from the upper surface of the spatula. The bosses may be 0.5 to 1 millimeter thick and they can be felt by touch from a gloved surgeon.

[0048] Preferably, the surgical spatula is 15-20 centimeters long, 1-2 centimeters wide, and 1-4 millimeters thick. The radius of curvature of the spatula in a stationary state is in the range of 150-200 millimeters.

[0049] Preferably, surgical spatulas are manufactured from a material having a rigidity between 2 and 4 gigapascals.

[0050] More preferably, the spatula is made of a transparent polymer material, which allows the surgeon to directly observe the spatula-treated tissue during the procedure and confirm that no excessive pressure is being applied. Of particular note is the problem that with conventional opaque spatulas, the tissue under compression cannot be visualized during the procedure, and brain damage is only confirmed after the spatula has been removed.

[0051] In preferred embodiments, the spatula is manufactured from a material selected from polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), and low-density polyethylene (LDPE). These are transparent polymers.

[0052] In one embodiment, the surgical spatula is provided with a constricted section in its cross-section, the function of which is to allow two portions of the spatula located on opposite sides of the constricted section to rotate relative to each other. The constricted section thus forms an elastic joint that limits or prevents the transmission of rotational force from the portion of the spatula held by the surgeon to the portion of the spatula in contact with the patient's tissue, thereby reducing the pressure that the edge of the spatula applies to the tissue.

[0053] In situations where a surgeon inadvertently tilts the grasped portion of the spatula toward the tissue being spatulate, the portion of the spatula in contact with the patient's tissue will actually rotate less than the portion of the spatula grasped by the surgeon, and therefore the spatula will not act only on the edge or primarily on that edge.

[0054] Therefore, the constricted portion of the cross-section functions as a rotational limiting device, ensuring that the spatula portion in contact with the patient's tissue remains as flat and in close contact with the tissue as possible, and limiting or preventing the spatula from cutting the tissue with any of its edges.

[0055] Preferably, the constricted section is formed by two notches or indentations located on either side of the longitudinal axis of the spatula, each of which is cut into the edge of the spatula. The constricted section is the portion of the spatula between these two notches. More preferably, the two notches extend perpendicular to the longitudinal axis of the spatula and extend toward each other to a portion of the spatula that is, for example, the intermediate portion between the third and fourth indicators, or between the two tactile and / or visual indicators.

[0056] In other words, the spatula portion located between the two notches forms an elastic hinge, allowing the spatula portion on one side of the notch, which the surgeon is holding, to rotate relative to the spatula portion on the opposite side of the notch, which is intended to contact the patient's tissue.

[0057] Preferably, the constricted portion of the cross-section extends 2 to 5 millimeters along the longitudinal axis and is located at 40 to 50 percent of the spatula's length, which is closer to the second end than to the first end when measured from the second end (i.e., the opposite end from the gripping end).

[0058] An optional additional feature of the spatula is that by forming the spatula from a transparent material such as polycarbonate, it can be used to guide light to the surgical site. It is sufficient to have a light source at the first end of the spatula, so that the light ray propagates inside the spatula, reflects repeatedly on its inner surface, reaches the second end, and then exits to illuminate the tissue. In other words, the spatula functions like an optical fiber, and the light generated by the light source is reflected at the tissue in the area of ​​contact with the spatula, where it is most needed, which is beneficial to the surgeon. [Brief explanation of the drawing]

[0059] Further features and advantages of the present invention will become clearer from the description of preferred but non-exclusive embodiments described below with reference to the accompanying drawings. These embodiments are illustrative for illustrative purposes only and are not limiting.

[0060] [Figure 1] Figure 1 is a perspective view of the surgical spatula according to the present invention.

[0061] [Figure 2] Figure 2 is a top view of the surgical spatula shown in Figure 1.

[0062] [Figure 3] Figure 3 is a side view of the surgical spatula shown in Figure 1.

[0063] [Figure 4] Figure 4 is a photographic perspective view of a surgical spatula according to the present invention, showing the first configuration corresponding to an applied pressure of 15 millimeters of mercury (approximately 1999 Pascals) when pulling on pig brain tissue.

[0064] [Figure 5] Figure 5 is a photographic perspective view of the surgical spatula according to the present invention, showing a second configuration corresponding to the applied pressure of 22 millimeters of mercury (approximately 2933 pascals) when pulling on pig brain tissue.

[0065] [Figure 6] Figure 6 is a photographic perspective view of the surgical spatula according to the present invention, showing a third configuration corresponding to the applied pressure of 30 millimeters of mercury (approximately 3999 Pascals) when pulling on pig brain tissue.

[0066] [Figure 7]Figure 7 is a photograph showing a fluoroscopic view of the surgical spatula according to the present invention, illustrating a fourth configuration corresponding to the applied pressure of 45 millimeters of mercury (approximately 5999 Pascals) when pulling on pig brain tissue.

[0067] [Figure 8] Figure 8 is a combination of six photographs of pig brain tissue magnified 40 times under a microscope, showing the tissue before traction and after traction using a conventional spatula technique.

[0068] [Figure 9] Figure 9 is a combination of 12 microscopic images of pig brain tissue magnified 40 times, showing the tissue before traction and after traction using a conventional spatula technique.

[0069] [Figure 10] Figure 10 is a longitudinal cross-sectional view of the spatula shown in Figure 1, and is equipped with a light source. [Modes for carrying out the invention]

[0070] The surgical spatula 1 according to the present invention (hereinafter referred to as "spatula 1" for simplicity) is shown in Figure 1 as a perspective view from below. Spatula 1 has a one-piece structure, that is, it is not an assembly of multiple parts, but is molded from a single element. Spatula 1 has a thin plate-like shape, and its length and width are much larger than its thickness. Spatula 1 extends from a first end 2 for the surgeon to grasp (intended to be held with one hand) to a second end 3 located on the opposite side of the first end 2, for applying pressure to the patient tissue and performing traction.

[0071] In particular, in Figure 2, at the second end 3, a region 3' corresponding to the area where the spatula 1 is in ideal contact with the tissue to be pulled is hatched. This region 3' can also be defined as a pre-set contact area 3' or working area 3' at the end 3 of the spatula 1. In the illustrated example, the area of ​​the contact area 3' is approximately 315 square millimeters. As will be discussed later, the pressure values ​​applied during pulling assume that the spatula 1 is in ideal contact with the tissue across the entire contact area 3'.

[0072] Figure 2 shows a top view of spatula 1 in a straightened (flattened) state, and Figure 3 is a side view of spatula 1.

[0073] As shown in Figures 1 and 3, the spatula 1 is normally arched, that is, curved in an arc when not in use. As will become clear below, the spatula 1 may undergo elastic bending during use, as a result of which the spatula 1 may become completely straight and reach a horizontal configuration, i.e., a flat state. The reference symbol R indicates the radius of curvature, which is equal to 167 millimeters in the example of the spatula 1 shown, but can generally range from 150 millimeters to 200 millimeters.

[0074] In the examples shown in Figures 1-3, the spatula 1 has a length L of approximately 17 centimeters; the width W2 of the first end 2 is equal to 12 millimeters, and the width W3 of the second end 3 is equal to 15 millimeters, i.e., the second end 3 is slightly wider than the first end 2. Generally, the width dimension can be in the range of 1 to 2 centimeters. The thickness S of the illustrated spatula 1 is equal to 2 millimeters, and generally can be in the range of 1 to 4 millimeters.

[0075] Spatula 1 is transparent and is preferably manufactured by molding polycarbonate (PC). Alternatively, other transparent polymers, such as polymethyl methacrylate (PMMA), polystyrene (PS), or low-density polyethylene (LDPE), can be used.

[0076] Ideally, Spatula 1 is manufactured from polycarbonate with a rigidity between 2 and 4 gigapascals.

[0077] Spatula 1 is equipped with one or more tactile and / or visual indicators 4-7. In the example shown in Figures 1-3, spatula 1 includes four tactile and / or visual indicators 4-7; these are bosses 4-7 protruding from the top surface of spatula 1. Bosses 4-7 are aligned along the longitudinal axis X of the spatula and are 0.5-1 millimeter thick. Bosses 4-7 can be visually observed by the surgeon and can also be detected by touch through a glove. Each boss 4-7 has the task of indicating the precise gripping position of spatula 1, which uniquely corresponds to the precise value of the bending load of spatula 1, as will be described later.

[0078] The bosses 4 are positioned along the vertical axis X according to the pitch interval. As shown in Figure 3, O indicates the vertex of the central angle formed by the spatula 1 in a stationary state, and R indicates the radius of curvature. The first boss 4 is located at a central angle of 22 degrees with the first end 2 of the spatula 1, the second boss 5 is located at a central angle of 27 degrees with the first end 2 of the spatula 1, the third boss 6 is located at a central angle of 31 degrees with the first end 2 of the spatula 1, and the fourth boss 7 is located at a central angle of 36 degrees with the first end 2 of the spatula 1.

[0079] Therefore, the first boss 4 and the second boss 5 are spaced at an angle of equal pitch of 5 degrees, the second boss 5 and the third boss 6 are spaced at an angle of equal pitch of 4 degrees, and the third boss 6 and the fourth boss 7 are spaced at an angle of equal pitch of 5 degrees.

[0080] Spatula 1 also includes a section of constriction 8 located between the third boss 6 and the fourth boss 7, as shown in the examples in Figures 1-3. The section of constriction 8 is achieved by providing two opposing notches 9 and 10 on the edge of spatula 1. The notches 9 and 10 are 1-2 millimeters deep, opposite each other, and have a longitudinal range L' equal to 2-5 millimeters. The distance of the section of constriction 8 calculated from the second end 3 is between 40-50% of the length L of spatula 1.

[0081] Each tactile and / or visual indicator 4–7 corresponds to a gripping position in which the surgeon holds the spatula 1, and at that gripping position, the spatula 1 provides a predetermined bending load that is quantitatively known and certified by the manufacturer. In other words, the tactile and / or visual indicators 4–7 constitute a stepped scale of the bending load of the spatula, i.e., a stepped scale of the load that the spatula 1 provides when straightened, and therefore the pressure applied to the tissue being pulled by the same spatula 1.

[0082] For example, the accuracy of the certification can be verified by conducting a test using a pressure sensor; specifically, the contact area of ​​spatula 1 is brought into contact with the pressure sensor, and pressure is applied until spatula 1 is completely straightened and flattened. At this point, the pressure applied to the sensor is measured, and the value must match the certified pressure.

[0083] When a surgeon performs tissue traction with spatula 1, the spatula tends to straighten, bending from the arched configuration shown in Figure 3 to the flat configuration shown in Figure 2, with no further bending possible, switching from concave to convex. Thus, each tactile and / or visual indicator 4-7 provides an indication of the maximum pressure applied to the tissue during traction when spatula 1 is straightened.

[0084] In the illustrated example, the four tactile and / or visual indicators 4–7 correspond to maximum pressure values ​​equivalent to 15 mm of mercury, 22 mm of mercury, 30 mm of mercury, and 45 mm of mercury, respectively. These values ​​correspond to the pressure applied when the surgeon has the entire contact area 3' in contact with the tissue, and not the pressure applied by only a portion of the end 3' or only the edge.

[0085] The constricted portion 8 constitutes an elastic hinge that allows the portion of the spatula held by the surgeon to rotate relative to the portion of the spatula 1 that is in contact with the tissue being pulled. In other words, the constricted portion 8 is a rotation limiting device that restricts the transmission of rotation to the portion of the spatula 1 that is in contact with the tissue in order to prevent the tissue from being cut by any of the edges of the spatula 1.

[0086] The functions of bosses 4-7 and the constricted section 8, as well as the general operation of spatula 1, will be explained in relation to Figures 4-7.

[0087] Figures 4-7 are photographs related to craniotomy experiments in anesthetized pigs. In particular, photographs 4-7 show the pig brain after the dura mater has been opened, which is the thick outermost tissue that protects the spinal cord and contains cerebrospinal fluid. Accordingly, a traction test of the brain parenchyma P was performed with a spatula 1' according to the present invention. The spatula 1' has four black-colored visual indicators 4-7 on the transparent plastic material of the spatula 1'.

[0088] Figure 4 shows a scene of traction of brain parenchyma P. The surgeon holds the spatula 1' between the thumb and index finger of his left hand, so that the first visual indicator 4 is barely visible. In this position, the surgeon is aware that the pressure applied to brain parenchyma P is certainly less than 15 millimeters of mercury, as long as the spatula 1 still retains some curvature and is not completely straightened, as long as it is in contact with the tissue across its entire contact area 3'. The surgeon is also aware that by increasing the pressure applied to the spatula 1, the pressure will reach 15 millimeters of mercury when the spatula 1 is completely straightened. Therefore, a surgeon who always wants to apply a pressure of less than 15 millimeters of mercury to brain parenchyma P can perform tissue traction without completely straightening the spatula 1'.

[0089] Figure 5 shows another moment during traction of brain parenchyma P. The surgeon grasps the spatula 1' in his left hand between his thumb and index finger at the position of the second visual indicator 5. In this position, the surgeon recognizes that the pressure applied to the brain parenchyma will be equal to a maximum of 22 millimeters of mercury when the spatula 1 is fully straightened, by maintaining contact across the entire contact area 3'. Therefore, a surgeon who always wants to apply a pressure of less than 22 millimeters of mercury to parenchyma P only needs to perform the tissue traction without fully straightening the spatula 1'.

[0090] Figure 6 shows another moment during traction of brain parenchyma P. The surgeon grasps the spatula 1' in his left hand between his thumb and index finger, at the position of the third visual indicator 6. In this position, the spatula 1' is fully straightened, and the surgeon recognizes that the pressure applied to the brain parenchyma is exactly equal to a 30-millimeter column of mercury by maintaining contact across the entire contact area 3'. Therefore, a surgeon who always wants to apply a pressure of less than a 30-millimeter column of mercury to parenchyma P only needs to perform the tissue traction without fully straightening the spatula 1'.

[0091] Figure 7 shows another moment during traction of brain parenchyma P. The surgeon grasps the spatula 1' in his left hand between his thumb and index finger at the position of the fourth visual indicator 7. In this position, the spatula 1' is fully straightened, and the surgeon recognizes that the pressure applied to the brain parenchyma is exactly equal to a 45 millimeter column of mercury by maintaining contact across the entire contact area 3'. Therefore, a surgeon who always wants to apply a pressure of less than a 45 millimeter column of mercury to parenchyma P only needs to perform the tissue traction without fully straightening the spatula 1'.

[0092] From the above perspective, Spatula 1 allows surgeons to accurately calibrate the maximum pressure applied to the tractioned tissue, which offers a clear advantage in terms of favorable surgical outcomes.

[0093] The sectional constriction 8 is located between the third visual indicator 6 and the fourth visual indicator 7; as long as the surgeon grasps the spatula 1' at the position of visual indicator 4, 5, or 6, and therefore upstream of the sectional constriction 8, any rotation that the surgeon mistakenly imparts to part 2 of the spatula 1' will be propagated to part 3 of the spatula 1' only to a limited extent, i.e., with a smaller amplitude. This is precisely due to the elastic deformation of the sectional constriction 8. Thus, the function of the sectional constriction 8 is to ensure that the end 3 of the spatula 1' is in complete contact with the brain parenchyma P over as much of its entire surface as possible, thereby suppressing or preventing a situation that is prone to tissue damage, where only the edge of the spatula 1' comes into contact with the tissue.

[0094] Figure 8 shows microscopic images of a sample of porcine brain tissue, particularly brain parenchyma P. The sample was fixed in 10% neutral buffered formalin solution and embedded in paraffin using an automated tissue processing device (Donatello Series 2, Diapath BG, Italy). Sections 5 micrometers thick were cut (semi-automatic rotary microtome Galileo, Diapath, BG, Italy), and the sections were collected on poly-L-lysine coated slides. The tissue sections were deparaffinized with xylene, rehydrated stepwise with decreasing alcohol concentrations, and stained with hematoxylin-eosin and Masson-Goldner using an automated staining device (Giotto, Diapath, BG, Italy). The slides were then observed at 10x and 100x magnification under a microscope (Olympus) connected to a computer with image processing software.

[0095] In Figure 8: -A is an image of a control section of brain tissue, an unstrained section, magnified 40x; -B is an image of brain tissue from the same control section as A, but from a section that has not been subjected to traction, and is magnified 100 times; -C is an image of another section of the same brain tissue, which was pulled with a conventional spatula and magnified 40x. Nearly circular microhemorrhages due to localized tissue destruction are visible. This lesion was caused by excessive pressure applied locally with a conventional spatula; -D is an image of the same section of brain tissue shown in B, but magnified 100 times. A localized lesion where microhemorrhages have occurred is clearly visible. -E is an image of another section of the tractioned brain tissue, magnified 40x. Different areas of lesions are visible, characterized by microhemorrhages due to localized tissue destruction. These lesions were caused by excessive pressure applied locally with a conventional spatula; -F is an image of the same section of brain tissue shown in B, but magnified 100 times. The localized lesion where microhemorrhages occurred is clearly visible and occupies a large portion of the image.

[0096] A comparison of images C, D, E, and F with images A and B provides insight into the damage caused by excessive pressure applied to tissue, particularly brain tissue, with conventional spatulas.

[0097] Figure 9 shows the results of traction of porcine brain parenchyma P, which can be achieved by using spatula 1,1' according to the present invention. The sample was prepared as described above (hematoxylin-eosin staining).

[0098] In Figure 9: -A is an image of a control section of brain parenchyma P that was not subjected to traction, magnified 40 times; -B is an image of the same control section of brain parenchyma P from A, which was not subjected to traction, and is magnified 100 times; -C is an image of another section of the same brain parenchyma P, a section that has been tractioned and magnified at 40x magnification. Traction was performed using the spatula 1' of the present invention, grasped by the surgeon with the first visual indicator 4, as described and shown in relation to Figure 4, so that the pressure applied to the brain parenchyma P was always less than 15 millimeters of mercury (1999.83 Pascals), or at most 15 millimeters of mercury (with the spatula in a horizontal configuration). As shown in the figure, no lesions were observed; -D is an image of the same section of brain parenchyma P shown in C, but magnified 100 times; -E is an image of another section of the same brain parenchyma P, a section that has been tractioned and magnified at 40x magnification. Traction was performed using the spatula 1' of the present invention, grasped by the surgeon with a second visual indicator 5, so that the pressure applied to the brain parenchyma P was always less than 22 millimeters of mercury (2933.084 Pascals), or at most 22 millimeters of mercury (with the spatula in a horizontal configuration). As shown in the figure, minute lesions are observed, particularly hemorrhage in the localized area; -F is an image of the same section of brain parenchyma P shown in E, but magnified 100 times; -G is an image of another section of the same brain parenchyma P, a section that has been tractioned and magnified at 40x magnification. The traction was performed using the spatula 1' of the present invention, grasped by the surgeon with a third visual indicator 6, so that the pressure applied to the brain parenchyma P was always less than 30 millimeters of mercury (3999.66 Pascals), or at most 30 millimeters of mercury (with the spatula in a horizontal configuration). There is more microbleeding and early tissue destruction as shown in the figure.

[0099] -H is an image of the same section of brain parenchyma P shown in G, but magnified 100 times; -I is an image of another section of the same brain parenchyma P, a section that has been tractioned and magnified at 40x magnification. The traction was performed using the spatula 1' of the present invention, and was carried out by the surgeon grasping with the fourth visual indicator 7, so that the pressure applied to the brain parenchyma P was always less than 45 millimeters of mercury (5999.49 Pascals), as described and shown in relation to Figure 7. As shown in the figure, lesions, particularly hemorrhage and tissue destruction, are observed in a larger area than those in the aforementioned images C-H; -J is an image of the same section of brain parenchyma P shown in I, but magnified 100 times; -K is an image of another section of the same brain parenchyma P, a section that has been tractioned and magnified at 40x magnification. Traction was performed using the spatula 1' of the present invention. As can be seen from the figure, a lesion, in particular hemorrhage, is observed in a limited area of ​​the upper right; -L is an image of the same section of brain parenchyma P shown in K, but magnified 100 times, allowing for a clearer visualization of the lesion.

[0100] A comparison of Figures 8 and 9 shows that Spatula 1' can minimize lesions to the brain parenchyma P under all its usage conditions, offering virtually the same advantages as a sensor-equipped spatula, but with the simplicity of a completely manual solution. Furthermore, it is highlighted that damage to the brain parenchyma begins as early as a pressure value of 30 millimeters of mercury (3999.66 Pascals), consistent with data currently presented in the literature.

[0101] Furthermore, the elastic hinge consisting of the cross-sectional narrowing portion 8 limits the rotation transmitted to the tissue, so that the spatulas 1, 1' function flat and do not cut the tissue at the edges; this means helps to achieve the excellent performance described above.

[0102] Figure 10 is a schematic, scale-independent longitudinal cross-sectional view of a straightened spatula 1 equipped with a light source 11 such as an LED. The LED 11 is located at the first end 2 and emits a ray 12, which propagates like an optical fiber within the material of the spatula 1, e.g., polycarbonate, and exits at the second end 3 to illuminate the pulled tissue, helping the surgeon identify any microbleeds in a timely manner.

Claims

1. A single-piece manual surgical spatula (1), which extends along a longitudinal axis (X) between a first end (2) and a second end (3), wherein the thickness (S) of the surgical spatula (1) is smaller than the length (L) and width (W2) of the surgical spatula (1), The surgical spatula (1) can be held with one hand between the first end (2) and the second end (3), The surgical spatula (1) is normally arched, and when in use, it can be bent in a direction that flattens or straightens depending on the pressure applied to one end (3) of the spatula. The surgical spatula (1) is characterized in that it comprises one or more tactile and / or visual indicators (4-7) aligned along the vertical axis (X), and each of these indicators indicates a gripping position that uniquely corresponds to a known bending load value of the surgical spatula (1).

2. A surgical spatula (1) according to claim 1, wherein the surgical spatula (1) has four tactile and / or visual indicators (4-7).

3. A surgical spatula (1) according to claim 2, wherein the tactile and / or visual indicators (4-7) correspond to the maximum pressure values ​​applied by the patient's tissue on the contact area (3') of the end (3) of the spatula when the spatula is fully straightened during use, and these maximum pressure values ​​are equal to 15 millimeters of mercury, 22 millimeters of mercury, 30 millimeters of mercury, and 45 millimeters of mercury, corresponding to approximately 1999 Pascals, 2933 Pascals, 3999 Pascals, and 5999 Pascals, respectively.

4. A surgical spatula (1) according to any one of the preceding claims, wherein the angular pitch between the tactile and / or visual indicators (4-7) is calculated with respect to the vertex (O) of the central angle intercepted by the surgical spatula (1) when the surgical spatula (1) is in an arch shape in a stationary state, and corresponds to 4 to 6 degrees.

5. A surgical spatula (1) according to claim 4, wherein the first tactile and / or visual indicator (4) is located at the first end (2) of the surgical spatula (1) at a central angle of 22 degrees, and the fourth tactile and / or visual indicator (7) is located at the first end (2) of the surgical spatula (1) at a central angle of 36 degrees.

6. A surgical spatula (1) according to any one of the preceding claims, wherein the tactile and / or visual indicators (4-7) are bosses protruding from the upper surface of the surgical spatula (1).

7. A surgical spatula (1) according to any one of the preceding claims, wherein the surgical spatula (1) has a length of 15 to 20 centimeters, a width of 1 to 2 centimeters, a thickness of 1 to 4 millimeters, and a radius of curvature (R) of 150 to 200 millimeters when the spatula is at rest.

8. A surgical spatula (1) according to any one of the preceding claims, wherein the surgical spatula (1) is made of a material having a rigidity of 2 to 4 gigapascals.

9. A surgical spatula (1) according to any one of the preceding claims, wherein the surgical spatula (1) is made from a transparent polymer material.

10. A surgical spatula (1) according to any one of the preceding claims, wherein the spatula (1) is made from a material selected from polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), or low-density polyethylene (LDPE).

11. A surgical spatula (1) according to any one of the preceding claims, comprising a constricted portion (8) in cross-section.

12. A surgical spatula (1) according to any one of the preceding claims, comprising two notches (9, 10) or indentations arranged opposite to the longitudinal axis (X), each indentation formed on the edge of the surgical spatula (1), wherein the two notches (9, 10) define a constricted portion (8) in the cross-section at a position where the surgical spatula (1) rotates.

13. A surgical spatula (1) according to claim 12, wherein the two notches (9, 10) extend perpendicular to the longitudinal axis (X) of the surgical spatula (1) and extend toward each other in the intermediate portion between the two tactile and / or visual indicators (6, 7).

14. A surgical spatula (1) according to claim 13, wherein a portion (8) of the surgical spatula (1) located midway between the two notches (9, 10) defines an elastic hinge, thereby enabling relative rotation between the portion of the spatula on one side of the notches (9, 10) and the portion of the spatula facing the notches (9, 10).

15. A surgical spatula (1) according to any one of claims 12 to 14, wherein the constricted portion (8) extends along the longitudinal axis, the constricted portion (8) extends 2 to 5 millimeters in length (L'), and further, the constricted portion (8) is located at 40 to 50 percent of the length of the surgical spatula (1), measured from the second end (3), that is, measured from the end opposite to the end of the grip.

16. A surgical spatula (1) according to any one of the preceding claims, comprising a transparent polymer material, a first end (2) comprising a light source, wherein light generated by the light source is reflected through the transparent material within the surgical spatula (1) and emitted from the second end (3) to illuminate a pulled tissue.

17. A surgical spatula (1) according to any one of the preceding claims, wherein the tactile and / or visual indicators (4-7) constitute a stepped scale of the bending load of the surgical spatula (1), that is, the load exerted when the surgical spatula (1) is straightened.

18. A surgical spatula (1) according to any one of the preceding claims, wherein the load value exerted when the surgical spatula (1) is straightened is certified for each tactile and / or visual indicator (4-7).

Images