PDA assistance device

Abstract

The invention relates to a PDA assisting device for performing a method for localizing the puncture site for a peridural catheter system (PDA), wherein a paramedian distance of an ultrasound head or a paramedian angular inclination of the ultrasound head can be input or adjusted on a first measuring scale, wherein a distance measured with the ultrasound head from the skin to the posterior complex can be input or adjusted on a hypotenuse measuring scale, wherein a depth of the posterior complex from the median incision can be calculated or read on a depth scale, wherein a cranial or caudal offset of the puncture site can be input or adjusted based on the first measuring scale, wherein a puncture depth and / or a puncture angle of a cannula can be determined by means of the PDA assisting device. The puncture depth and / or the puncture angle can either be calculated by means of software or read by means of a measuring board.The measuring board has a base (8), on which a depth scale (9) is applied. A slide (10) is displaceable along the depth scale (9). The slide (10) has an arm (11) extending perpendicular to the depth scale (9). The arm (11) has a measuring scale (12) for setting the paramedian distance or the offset of the puncture site (P). A swing arm (13) is arranged on the base (8) so as to be pivotable about a zero point of the depth scale (9). The swing arm (13) has a hypotenuse measuring scale (14), and the hypotenuse measuring scale (14) is used for setting the distance and for reading the puncture depth.

Description

[0001] The invention relates to a PDA helper device having the features of the preamble of patent claim 1.

[0002] The placement of an epidural catheter (PDA) is a critical step in medical practice, particularly in pain management and anesthesia. Currently, anatomical landmarks are primarily used to locate the puncture site for the PDA, and various techniques such as the loss-of-resistance method, the hanging-drop technique, and the administration of a test dose are employed to verify the position. Despite these established procedures, accurately predicting the insertion depth and angle of the cannula remains a challenge for physicians, as they must largely rely on their experience and skill.

[0003] From DE 24 43 558 A1, it is known to use an ultrasound head to precisely position cannulas for biopsy, anesthesia, or the like, in order to locate the target area for the cannula. In order to guide the cannula into the target area located by the ultrasound head, it is known to attach a guide device for the cannula to the ultrasound head. The guide device serves to force the cannula into the located target area, whereby the cannula and its positioning can also be observed in the ultrasound image. It is known to attach a holder to the ultrasound head, on which a guide sleeve is pivotably arranged in the scanning plane (cross-sectional image plane, scan plane) of the ultrasound head. The guide sleeve can be pivoted at an angle and fixed by means of a clamping screw. The cannula is axially displaceable in the guide sleeve.

[0004] US 2016 / 0 022 308 A1 describes a medical system for the precise placement of needles, for example, during epidural anesthesia or lumbar punctures. It combines an ultrasound probe, a body guide, and an instrument guide that guides the needle perpendicular to the body surface. The body guide lies flat on a locally flat area of ​​the body surface and serves as a reference surface for the vertical guidance of the needle. The instrument guide is designed to guide the needle precisely perpendicular to the body surface. The probe captures a 3D volume image of the target area, including the needle, and can be positioned at variable angles (5°–85°). The system processes the image data, calculates an image plane running in the direction of needle insertion, and generates "thick-slice" images. These enable continuous monitoring of the needle position in real time, thus increasing safety and accuracy during needle placement.

[0005] The invention is based on the object of providing a PDA helper device that improves the safety and accuracy of PDA placement.

[0006] The invention is achieved by a PDA assistive device with the features of patent claim 1. The PDA assistive device serves to carry out a method for locating the puncture site for a peridural catheter (PDA). A paramedian distance of an ultrasound head or a paramedian angle of the ultrasound head can be input or adjusted on a first measuring scale. A distance measured with the ultrasound head from the skin to the posterior complex can be input or adjusted on a hypotenuse measuring scale. A depth of the posterior complex from the median section can be calculated or read off a distance scale. A medial or caudal offset of the puncture site can be input or adjusted using the first measuring scale. A puncture depth and / or an insertion angle of a cannula can be determined and displayed using the PDA assistive device.

[0007] A convex ultrasound transducer is placed paramedianally, i.e. a few millimeters to centimeters lateral to the spine, perpendicular to the skin and tilted to the side to visualize the posterior complex in the sagittal oblique section (the "paramedian" section). A "paramedian" section is chosen because a median section directly above the spine is not possible at all levels of the spine, depending on the patient. After identifying the posterior complex in the "paramedian" section, the distance from the skin to the posterior complex is measured, which is possible with most ultrasound machines. There are then two possible further procedures. First, the angle of the ultrasound transducer can be used. A plumb line is drawn perpendicular to the measured depth of the back, and the angle can be estimated or measured by tilting the ultrasound transducer.The second option is to measure the distance from the spine to the center of the ultrasound probe. These values ​​are then input into the PDA helper device. This measures the depth of the posterior complex from the median section, i.e., directly on the spine from the skin. This value, plus the desired insertion depth (either caudal, downward, or cranial, upward), is then input into the PDA helper device, and the output values ​​determine the insertion depth and insertion angle of the cannula.

[0008] Two different embodiments of the invention are described below.

[0009] In a first embodiment of the invention, the PDA helper device comprises a data processing system, wherein software is stored on a memory of the data processing system and the software is executable by means of a processing unit, wherein the software has at least one input field for the paramedian distance and / or for the paramedian angular inclination, an input field for the distance measured with the ultrasound head from the skin to the posterior complex and an input field for the cranial or caudal offset of the puncture site.

[0010] The software can be used to calculate the penetration depth and angle.

[0011] The PDA helper device automatically performs various calculations via the software to determine the missing values, namely the insertion depth and the insertion angle, based on the given inputs “paramedian offset distance a_para” or “paramedian angular inclination gamma_para”, “measured distance E_sag of the posterior complex in the sagittal oblique section” and “caudal or medial offset V”.

[0012] The calculation of the depth T of the posterior complex from the median section can be done using the Pythagorean theorem: T=(E_sag 2 -a_para 2 ) ^1 / 2 when the paramedian offset is entered.

[0013] If the paramedian angular inclination gamma_para is entered relative to the normal to the skin, then the depth of the posterior complex can be calculated using T=cos(gamma_para)*E_sag.

[0014] The calculation of the penetration depth ET is also carried out using the Pythagorean theorem: ET=(T 2 +V 2 ) 1 / 2

[0015] The insertion angle alpha between the skin and the cannula can be calculated by alpha = arcsin (T / ET).

[0016] The angular offset beta of the cannula relative to the perpendicular position to the skin can be calculated as beta=90°-alpha.

[0017] These calculations allow the program to determine the relevant parameters for the placement of an epidural catheter, thereby improving the accuracy and safety of the procedure.

[0018] The data processing system has a display and the software can be used to show the penetration depth and the penetration angle on the display.

[0019] The data processing system is preferably part of an ultrasound system. The ultrasound images are initially shown on the display.

[0020] The ultrasound system preferably features a convex ultrasound transducer placed paramedian on the skin to allow for accurate visualization of the posterior complex in the sagittal oblique section. Using this approach allows for consideration of patient anatomical variations and more precise localization of the puncture site.

[0021] The invention further relates to a computer program product comprising program code implementing instructions that can be executed to perform the method.

[0022] The PDA helper device works by measuring the distance from the skin to the posterior complex and inputting this data into the PDA helper device. The helper device then calculates the insertion depth and angle of the cannula based on the measured ultrasound values ​​and user input. Integrating ultrasound technology into the PDA process provides an additional safety measure, reducing reliance on purely empirical methods and improving placement precision.

[0023] In an alternative embodiment, the PDA assistant device is designed as a mechanically operating device. The PDA assistant device acts as a kind of "measuring board" on which several values ​​can be set and read.

[0024] The PDA assistant device comprises a base, particularly in the form of a base plate, with a depth scale applied to the base. A slider is movable along the depth scale. The slider can engage a slot extending along the depth scale in the base, and the slider is movable along the slot.

[0025] The slider has an arm extending perpendicular to the depth scale, the arm having the first measuring scale for adjusting the paramedian distance and for adjusting the offset of the puncture site.

[0026] At the base, a pivoting arm is arranged so as to pivot around a zero point of the depth scale, whereby the pivoting arm has the hypotenuse measuring scale and the hypotenuse measuring scale is used to set the distance and to read the puncture depth.

[0027] This invention aims to protect the described PDA helper device and to promote its application in medical practice by enabling the PDA helper device to perform an advanced and reliable method for locating the puncture site for epidural catheter insertions.

[0028] There are now numerous possibilities for embodying and developing the invention. For this purpose, reference is first made to the claims subordinate to claim 1. A preferred embodiment of the invention is explained in more detail below with reference to the drawing and the accompanying description. The drawing shows: Fig. 1 in section along the transverse plane, highly schematically an ultrasound head arranged paramedian on the back, Fig. 2 in section along the sagittal plane, a highly schematic view of a puncture site for epidural catheters, and Fig. 3 shows a schematic plan view of a PDA helper device in the form of a measuring board.

[0029] Fig. Figure 1 shows how a particularly convex ultrasound probe 6 is placed paramedianally, i.e., a few millimeters to centimeters lateral to the spine 2, vertically onto the skin 1 and tilted to the side to visualize the posterior complex 4 in the sagittal oblique section (paramedian section). The spinal space 3 and the anterior complex 5 are also sketched in a highly schematic manner. The ultrasound probe 6 is inclined by the angle gamma_para to the perpendicular (not shown). The inclination, and thus the angle gamma_para, is measured or estimated.

[0030] A "paramedian" section is chosen because a median section, which lies directly above spine 2, is not possible at all levels of spine 2, depending on the patient. After identifying the posterior complex 4 in the "paramedian" section, the distance from skin 1 to the posterior complex 4 is measured, which is possible with most ultrasound scanners.

[0031] The value a_para describes the paramedian offset of the ultrasound probe. The value gamma_para describes the paramedian angular inclination of the ultrasound probe. The value E_sag describes the distance of the posterior complex measured using the ultrasound probe 6 in the sagittal oblique section.

[0032] There are two ways to determine the depth T of the posterior complex. First, the angle of the ultrasound probe can be used. A plumb line is drawn perpendicular to the measured depth of the back, and the angle gamma_para can be estimated or measured by tilting the ultrasound probe. The second option is to measure the paramedian offset a_para from spine 2 to the center of the ultrasound probe 6.

[0033] These values ​​are then entered into the PDA helper device. This determines the depth T of the posterior complex 4 from the median section, i.e., directly on the spine 2 from the skin 1.

[0034] In one embodiment, the PDA helper device is implemented by a data processing system with software for calculating and displaying the puncture depth and the puncture angle.

[0035] The calculation of the depth T of the posterior complex 4 from the median section is carried out using the software with the Pythagorean theorem: T=(E_sag 2 -a_para 2 ) ^12 when the paramedian offset is entered into the data processing system.

[0036] If the paramedian angular inclination gamma_para relative to the normal to the skin is entered into the data processing system, then the depth T of the posterior complex 4 can be calculated using T=cos(gamma_para)*E_sag.

[0037] Then you enter this value T plus the offset V (see Fig. 2) the puncture site P either caudally, downwards, or cranially, upwards into the PDA helper device, and the output values ​​​​determine the puncture depth and the puncture angle of the cannula.

[0038] The software also calculates the penetration depth ET using the Pythagorean theorem ET=(T 2 +V 2 ) 1 / 2

[0039] The penetration angle alpha between the skin and the cannula can be calculated using the software as alpha = arcsin(T / ET) or alpha = arctan(T / V). The values ​​are then displayed on a screen, specifically the ultrasound display. The software can be run on the ultrasound system's data processing unit.

[0040] In Fig. 3 shows a mechanical variant of the PDA helper device in the form of a so-called measuring board 7, on which several values ​​can be set and read.

[0041] The PDA aid device comprises a base plate 8, on which a depth scale 9 is applied. A slider 10 is arranged to be displaceable along the depth scale 9. The slider 10 engages with two guide lugs 18 in a slot 17 extending along the depth scale 10 in the base plate 8, and the slider 10 is displaceable along the slot 17.

[0042] The slider 10 has an arm 11 extending perpendicular to the depth scale 10, wherein the arm 11 has a measuring scale 12 for setting the paramedian offset a_para and for setting the offset V of the puncture site P. The measuring scale 12 begins at the depth scale 10.

[0043] A pivoting arm 13 is mounted on the base plate 8, pivotable about a zero point of the depth scale 10. The pivoting arm 13 has a hypotenuse measuring scale 14, which serves to set the distance E_sag and read the penetration depth ET. The pivoting arm 13 is pivotable along an angle scale 16, with the angle scale 16 being arranged in two sections for better readability. The angle scale indicates the angle of the pivoting arm 13 relative to the longitudinal extent of the depth scale 10.

[0044] The measuring board works as follows: Once the paramedian offset a_para has been determined, the corresponding position is selected on the measurement scale 12 of arm 11 on the slider. The measured distance E_sag of the posterior complex 4 in the sagittal oblique section is selected as the position on the hypotenuse scale 14 on the pivot arm 13. The pivot arm 13 and the slider are then pivoted and shifted such that the two selected positions form an intersection point of the pivot arm 13 and arm 11 of the slider 10. The resulting position of the slider 10 on the depth scale corresponds to the depth T of the posterior complex 4.

[0045] Once the paramedian angular inclination has been determined, the swivel arm 13 is aligned on the angle scale 16 at the corresponding angular position of the determined angular inclination. The measured distance E_sag of the posterior complex 4 in the sagittal oblique section is selected as the position on the hypotenuse scale 14 on the swivel arm 13. The slider 10 is moved so that its arm 11 is positioned at the selected position on the hypotenuse scale 14 of the swivel arm 13. The resulting position of the slider 10 on the depth scale corresponds to the depth T of the posterior complex 4.

[0046] The slider 10 is now held in this position. The pivoting arm 13 is then pivoted so that the intersection point of the pivoting arm 13 is located at the caudal or medial offset V of the puncture site P on the measuring scale 12. The puncture depth ET can now be read at the intersection point on the hypotenuse measuring scale 14, and the puncture angle alpha can be read on the angle scale 16. List of reference symbols 1 skin 2 Spine 3 Spinal space 4 Posterior complex 5 Anterior complex 6 Ultrasound head 7 PDA helper device in the form of a measuring board 8 Base plate 9 depth scale 10 sliders 11 Arm of the slider 12 measuring scale on arm 13 Swivel arm 14 Hypotenuse measurement scale 15 Bearing pin of the swivel arm 16 angle scale 17 Slot 18 guide lugs a_para paramedian offset gamma_para paramedian angle inclination E_sag measured distance of the posterior complex in the sagittal oblique section T Depth of the posterior complex from the median section P Puncture site V caudal or medial offset of the puncture site ET penetration depth Alpha insertion angle

Claims

[1] PDA helper device for carrying out a method for locating the puncture site for a peridural catheter (PDA), wherein a paramedian distance of an ultrasound head or a paramedian angular inclination of the ultrasound head can be entered or adjusted on a first measuring scale, wherein a distance measured with the ultrasound head from the skin to the posterior complex can be entered or adjusted on a hypotenuse measuring scale, wherein a depth of the posterior complex from the median section can be calculated or read off a depth scale, wherein a cranial or caudal offset of the puncture site can be entered or adjusted using the first measuring scale, wherein a puncture depth and / or a puncture angle of a cannula can be determined by means of the PDA helper device. [2] PDA helper device according to claim 1, characterized bythat the PDA helper device has a data processing system, wherein software is stored on a memory of the data processing system and the software can be executed by means of a processing unit, wherein the software has at least one input field for the paramedian distance and / or for the paramedian angular inclination, an input field for the distance measured with the ultrasound head from the skin to the posterior complex and an input field for the medial or caudal offset of the puncture site. [3] PDA helper device according to claim 2, characterized by that the penetration depth and the penetration angle can be calculated using the software. [4] PDA helper device according to claim 3, characterized by that the data processing system has a display and that the puncture depth and the puncture angle can be shown on the display using the software. [5] PDA helper device according to claim 4, characterized bythat the data processing system is part of an ultrasound system and that ultrasound images can be displayed on the display. [6] PDA helper device according to claim 1, characterized by that a base (8) is provided, a depth scale (9) being applied to the base (8), a slider (10) being displaceable along the depth scale (9), the slider (10) having an arm (11) extending perpendicular to the depth scale (9), the arm (11) having a measuring scale (12) for setting the paramedian distance or the offset of the puncture site (P), a pivoting arm (13) being arranged on the base (8) so as to be pivotable about a zero point of the depth scale (9), the pivoting arm (13) having a hypotenuse measuring scale (14) and the hypotenuse measuring scale (14) being used to set the distance and to read the puncture depth. [7] PDA helper device according to claim 6, characterized bythat the slider (10) engages in a slot (17) extending along the depth scale (9) in the base (8), wherein the slider (10) is displaceable along the slot (17). [8] A computer program product comprising program code implementing instructions executable to perform the method of any one of claims 1 to 5.

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