Pressure measurement system, patient body position fixture for lithotomy position surgical operation, and method of collecting pressure information

Abstract

To provide a pressure measurement system for measuring pressure allied on a sacral region of a patient when a surgical operation is performed at a lithotomy position.SOLUTION: A pressure measurement system for measuring a pressure applied onto a sacral region of a patient when a surgical operation is performed at a lithotomy position, comprises: a pressure sensor array; and a calculation part calculating a measured value of pressure around the sacral region of a patient obtained from the pressure sensor array. When gravity-direction is defined as Z-direction, a direction orthogonal to the gravity-direction is defined as X-direction, and a direction orthogonal to the Z-direction and the X-direction is defined as Y-direction, the pressure sensor array can measure stresses in the X-direction and Y-direction when the sacral region of a patient comes into contact with the pressure sensor array. When a direction from the right side to the left side of the patient or a direction from the left side to the right side of the patient when the patient is viewed in front is defined as X-direction, and a direction from the feet to the head of the patient or a direction from the head to the feet of the patient when the patient is viewed in front is defined as Y-direction, the calculation part partitions the pressure sensor array into prescribed areas and calculates stresses in the X-direction and the Y-direction by the partitioned area unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The disclosure in the present application relates to a pressure measurement system for measuring the pressure on the sacrum of a patient during surgery in the lithotomy position, a patient position fixing device for lithotomy surgery including the pressure measurement system, and a method for collecting pressure information related to a pressure sensor array when the patient's position is changed to the lithotomy position.

Background Art

[0002] It is known that surgical-related pressure disorders occur due to long-term pressure on tissues during surgery. In particular, the lithotomy position used in lower gastrointestinal, urological, and gynecological surgeries is a special position, so it is considered to have a high risk of surgical-related pressure disorders. In addition, in laparoscopic surgery and robot-assisted surgery, which have become popular in recent years, since position conversion is required during surgery, the risk of surgical-related pressure disorders is further increased.

[0003] As a method for measuring the pressure on a patient supported by a patient position fixing device, for example, Patent Document 1 describes measuring the pressure exerted by the patient on the mat by arranging a sensor array on the mattress.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the invention described in Patent Document 1 only discloses a general technique for measuring the pressure of a patient supported by a patient position fixing device. It is not known what pressure on the patient, when measured for a patient supported in the lithotomy position, can reduce the risk of surgical-related pressure disorders occurring.

[0006] The disclosure in the present application is made to solve the above problems. As a result of intensive research by the present inventors, it has been newly found that the above problems can be solved by (1) measuring the pressure around the sacrum using a pressure sensor array and (2) dividing the pressure sensor array into predetermined regions and calculating the stress in the X direction and the Y direction in units of the divided regions.

[0007] That is, the object of the disclosure in the present application is to provide a pressure measurement system for measuring the pressure on the patient's sacrum during surgery in the lithotomy position, a patient position fixing device for lithotomy surgery including the pressure measurement system, and a method for collecting pressure information related to a pressure sensor array when the patient's position is changed to the lithotomy position.

Means for Solving the Problems

[0008] The disclosure of the present application relates to the following pressure measurement system, patient position fixing device for lithotomy surgery, and method for collecting pressure information.

[0009] (1) A pressure measurement system for measuring the pressure on the patient's sacrum during surgery in the lithotomy position, the pressure measurement system comprising: a pressure sensor array; and an arithmetic unit that calculates the measured values of the pressure around the patient's sacrum obtained from the pressure sensor array; and the pressure sensor array is configured to: when the Z direction is defined as the direction of gravity, the X direction is defined as the direction perpendicular to the direction of gravity, and the Y direction is defined as the direction perpendicular to the Z direction and the X direction, when the patient's sacrum comes into contact, the stress in the X direction and the Y direction can be measured; the arithmetic unit is configured to: when the patient is viewed from the front, the X direction is defined as the direction from the right side to the left side or from the left side to the right side of the patient; when the patient is viewed from the front, the Y direction is defined as the direction from the head to the feet or from the feet to the head of the patient; Divide the pressure sensor array into a predetermined area, and calculate the stress in the X direction and the Y direction in units of the divided areas. Pressure measurement system. (2) A plurality of pressure-sensitive elements are arranged in the pressure sensor array. The calculation unit divides the area so that the number of pressure-sensitive elements included in one area is 1. The pressure measurement system according to (1) above. (3) A plurality of pressure-sensitive elements are arranged in the pressure sensor array. The calculation unit divides the area so that the number of pressure-sensitive elements included in one area is 2 or more, and the divided areas are even numbers. The pressure measurement system according to (1) above. (4) The calculation unit calculates the vectors of the stress in the X direction and the Y direction for each of the divided areas. The pressure measurement system according to (3) above. (5) The pressure sensor array can measure the stress in the Z direction. The calculation unit In addition to calculating the stress in the X direction and the Y direction in units of the divided areas, Calculate the stress in the Z direction in units of the divided areas. The pressure measurement system according to (1) above. (6) Further includes a display unit that displays the results calculated by the calculation unit. The pressure measurement system according to any one of (1) to (5) above. (7) Further includes a determination unit that determines whether a patient is likely to develop a surgery-related pressure disorder based on the results calculated by the calculation unit. The pressure measurement system according to any one of (1) to (5) above. (8) Includes the pressure measurement system according to any one of (1) to (5) above. Patient position fixing device for lithotripsy surgery. (9) A method for collecting pressure information related to a pressure sensor array when performing surgery in the lithotomy position using a pressure measurement system, The pressure measurement system is A pressure sensor array, a calculation unit that calculates measurement values of pressure around the sacrum of a patient obtained from the pressure sensor array, comprising, The method includes: a step of arranging the patient so that the sacrum of the patient abuts against the approximate center of the pressure sensor array; a posture changing step of changing the posture of the patient positioning fixture on which the patient is placed to a posture during surgery in the lithotomy position; a calculation step of calculating the pressure applied to the pressure sensor array after the posture changing step; comprising, defining the direction of gravity as the Z direction, the direction perpendicular to the direction of gravity as the X direction, and the direction perpendicular to the Z direction and the X direction as the Y direction, defining the direction from the right side to the left side or from the left side to the right side of the patient as the X direction when viewing the patient from the front, defining the direction from the head to the feet or from the feet to the head of the patient as the Y direction when viewing the patient from the front, The calculation step includes: dividing the pressure sensor array into a predetermined region, and calculating the stress in the X direction and the Y direction in units of the divided regions. Method.

Advantages of the Invention

[0010] By the pressure measurement system, the patient positioning fixture, and the method for collecting pressure information disclosed in the present application, the risk of occurrence of surgery-related pressure disorders can be reduced during surgery in the lithotomy position.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0012] Hereinafter, the pressure measurement system, the patient body position fixing device for lithotripsy surgery, and the method for collecting pressure information disclosed in the present application will be described. Note that the positions, sizes, ranges, etc. of the respective components shown in the drawings may not represent the actual positions, sizes, ranges, etc. for the sake of easy understanding. For this reason, the disclosure of the present application is not necessarily limited to the positions, sizes, ranges, etc. disclosed in the drawings.

[0013] Also, in this specification, (1) The numerical range represented by using "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value, (2) Regarding numerical values, numerical ranges, and qualitative expressions (for example, expressions such as "identical" and "the same"), they indicate numerical values, numerical ranges, and properties including generally acceptable errors in the technical field. (3) When described as "roughly 〇〇", in addition to the exact 〇〇, it includes shapes that are grasped as roughly 〇〇. It is interpreted as follows.

[0014] (Definition of directions) In this specification, the gravitational direction is defined as the Z direction. Also, the direction perpendicular to the gravitational direction is defined as the X direction, and the direction perpendicular to the Z direction and the X direction is defined as the Y direction.

[0015] (Embodiments of the pressure measurement system) With reference to FIGS. 1 to 3, some examples of embodiments of the pressure measurement system will be described. FIG. 1 is a schematic diagram showing the outline of the pressure measurement system. FIG. 2 is a diagram for explaining the outline of a patient position fixing device used in lithotripsy surgery. FIG. 3 is a schematic diagram for explaining the area divided by the calculation unit.

[0016] The pressure measurement system 1 according to the embodiment is used to measure the pressure on the sacrum of a patient during surgery in the lithotomy position. The pressure measurement system 1 includes at least a pressure sensor array 2 and a calculation unit 3.

[0017] The lithotomy position surgery is a position obtained by placing a patient on the patient position fixing device 4 shown in FIG. 2A, placing the patient in the supine position, spreading both legs, and fixing the lower limbs in a state where the knees are bent. The pressure sensor array 2 of the pressure measurement system 1 disclosed in the present application is arranged on the body pressure distribution mat 41 of the patient position fixing device 4 shown in FIG. 2A. FIG. 2B is a schematic diagram of the patient seen from the back. The patient is arranged on the body pressure distribution mat 41 in a state of looking up so that the sacrum is in contact with approximately the center of the pressure sensor array 2. Therefore, the pressure sensor array 2 can measure the pressure when it comes into contact with the periphery of the patient's sacrum.

[0018] The lithotomy position is mainly used in pelvic surgeries in the fields of lower gastrointestinal surgery, urology, and gynecology. Also, in laparoscopic surgery and robot-assisted surgery, a change in body position is required during the operation in the lithotomy position. The operation time takes about 3 to 6 hours, and the patient maintains the same posture during the operation. Therefore, when changing the patient's position to the lithotomy position or during the operation, if pressure is unevenly applied to the patient after the position change, surgical-related pressure disorders may occur.

[0019] In the example shown in FIG. 1, the pressure sensor array 2 includes a base material 21 and pressure-sensitive elements 22, and a plurality of pressure-sensitive elements 22 are arranged on the base material 21. The base material 21 is preferably deformed in accordance with the body shape of the patient when the patient is placed on the body pressure dispersion mat 41. Therefore, the base material 21 is preferably formed of a flexible material, for example, a thin resin sheet, cloth, etc., although it is not limited thereto. The pressure-sensitive element 22 is not particularly limited as long as it can measure at least the stress in the X and Y directions.

[0020] When changing the position to the lithotomy position, the pressure applied to the area around the sacrum is considered to be much smaller in the X and Y directions compared to the Z direction, considering the vector components of the weight. As described in paragraph

[0062] of Patent Document 1, "the pressure exerted by the patient on the mat is detected by the incorporated sensor array 22." The invention described in Patent Document 1 has in mind the measurement of pressure in the direction of gravity. On the other hand, as described above, the pressure measurement system 1 disclosed in the present application calculates the stress in the X and Y directions when calculating the pressure in the arithmetic unit, but does not include the stress in the Z direction in the calculation. When calculating the three directions of X, Y, and Z together, since the stress in the Z direction is large as described above, the value in the Z direction has a large influence when comparing the calculation results, and it is difficult to accurately analyze the difference in pressure between the X and Y directions. The pressure measurement system 1 disclosed in the present application has a remarkable and unprecedented effect that it can measure the imbalance on the patient when changing the position to the lithotomy position by analyzing the pressure in the X and Y directions that does not include the measured value in the Z direction.

[0021] The number of the pressure-sensitive elements 22 is not particularly limited as long as the pressure distribution around the sacrum can be measured. Although not limited, examples include 4 or more, 8 or more, 16 or more, 24 or more, 36 or more, 48 or more, 64 or more, 80 or more, 96 or more, etc. Note that the number of the pressure-sensitive elements 22 is the number arranged on one base material 21. Alternatively, the pressure sensor array 2 may be used by combining a plurality of pressure sensor arrays 2. In that case, the number of the pressure-sensitive elements 22 exemplified above means the total number of the pressure-sensitive elements 22 arranged in each pressure sensor array 2.

[0022] The pressure sensor array 2 is not particularly limited as long as it can measure the stresses in two directions, i.e., the X direction and the Y direction, as described above. Since the arithmetic unit 3 may calculate the stresses in two directions, i.e., the X direction and the Y direction, the pressure-sensitive element 22 itself may be able to measure the pressures in three directions including the Z direction. A commercially available product can be used as the pressure sensor array 2. Although not limited, examples include a shear stress sensor evaluation kit manufactured by Nissha Co., Ltd., an optical flexible pressure sensor sheet (https: / / www.t.u-tokyo.ac.jp / press / pr2023-09-12-001), etc.

[0023] The calculation unit 3 calculates the measured values of the pressure around the sacrum of the patient obtained from the pressure sensor array 2. More specifically, when the patient is placed on the pressure sensor array 2 and viewed from the front (see FIG. 1. The patient is omitted, but Head, Foot, Right, and Left correspond to the body orientation when the patient is viewed from the front.), when the direction from the right side to the left side or from the left side to the right side of the patient is defined as the X direction, and when the direction from the head to the foot or from the foot to the head of the patient is defined as the Y direction when viewed from the front, the calculation unit 3 divides the pressure sensor array 2 into predetermined regions and calculates the stress in the X direction and the Y direction in units of the divided regions. In FIG. 1, an example is shown in which the direction from the right side to the left side of the patient is the positive direction of the X direction and the direction from the head to the foot of the patient is the positive direction of the Y direction, but the positive direction may be the opposite direction to that in FIG. 1. Also, as a result obtained by the calculation unit 3 calculating the stress in the X direction and the Y direction, there are shear stresses in the X direction and the Y direction, vectors obtained by adding the stresses in the X direction and the Y direction, and the like.

[0024] Referring to FIG. 3, the region divided by the calculation unit 3 will be described. In the example shown in FIG. 3A, the calculation unit 3 divides the region R1 so that the number of pressure-sensitive elements 22 included in one region R1 is 1. In the example shown in FIG. 3A, the calculation unit 3 calculates the stress in the X direction and the Y direction for each region R1, in other words, for each pressure-sensitive element 22. In the example shown in FIG. 3A, since the stress in the X direction and the Y direction can be calculated for each pressure-sensitive element 22, the calculation result can be quantified as a distribution for each pressure-sensitive element 22. Therefore, by, for example, displaying the calculation result as a heat map, it is possible to easily visually recognize which part of the pressure sensor array 2 is under a large pressure.

[0025] On the other hand, in the example shown in FIG. 3B, the calculation unit 3 divides the region R2 (the region surrounded by the dotted line in FIG. 3B) so that the number of pressure-sensitive elements 22 included in one region R2 is two or more, and the number of divided regions R2 is an even number. The number of regions R2 shown in FIG. 3B is four, but the number of regions R2 may be two, or may be six, eight, ten, twelve, fourteen, sixteen, eighteen, twenty, etc. In the example shown in FIG. 3B, it is possible to calculate the degree of stress in units of the region R2, such as vectorizing the stress in the X direction and the Y direction calculated for each divided region. As shown in the embodiments described later, when the stress in the X direction and the Y direction for each region R2 is made into one vector, based on the measurement result at the start of body position conversion, the risk of occurrence of surgery-related pressure disorder can be predicted with a high probability. Therefore, it is possible to prevent the patient from being subjected to uneven pressure by changing the patient's body position according to the measurement result before starting the surgery, and further repeating the pressure measurement and body position conversion. As a result, the risk of the patient developing surgery-related pressure disorder can be reduced.

[0026] The calculation unit 3 may be provided exclusively for the pressure measurement system 1. Alternatively, the calculation unit 3 may be created by installing a program for performing the calculations described in the calculation unit 3 on a commercially available personal computer.

[0027] [Optional matters] Next, optional matters that can be adopted by the pressure measurement system 1 according to the embodiment will be described.

[0028] (Stress in the Z direction) The pressure-sensitive element 22 arranged in the pressure sensor array 2 may measure the stress in the Z direction in addition to the X and Y directions. Further, in addition to calculating the stress in the X and Y directions in units of the divided regions (R1, R2), the calculation unit 3 may calculate the stress in the Z direction in units of the divided regions (R1, R2). Generally, when the external pressure applied to a patient reaches 32 mmHg or more, it induces capillary occlusion and ischemic nerve injury, and when it is 60 mmHg or more, the muscle blood flow decreases by 41% and the local vascular resistance increases by 32%. The cause of neuropathy caused by body position has been reported as a blood flow disorder in the nerves. The stress in the Z direction is caused by the patient's own body weight, and as described above, the stress in the Z direction is greater than the stress in the X and Y directions. Therefore, by measuring the stress in the Z direction separately from the stress in the X and Y directions, the risk of the patient developing surgery-related pressure disorders is reduced.

[0029] (Display unit) The pressure measurement system 1 may include a display unit 5. When the pressure measurement system 1 includes the display unit 5, by displaying the result calculated by the calculation unit 3 on the display unit 5, the risk of occurrence of surgery-related pressure disorders during surgery can be monitored. The display unit 5 is not particularly limited as long as it can display the calculated result, and a commercially available display device such as a liquid crystal or an organic EL may be used.

[0030] (Judgment unit) The pressure measurement system 1 may include a judgment unit 6 that judges whether the risk of the patient developing surgery-related pressure disorders is high based on the result calculated by the calculation unit 3. As shown in the embodiments described later, in the present application, by calculating the stress in the X and Y directions, it was possible to distinguish with high accuracy between the presence and absence of surgery-related pressure disorders. Therefore, when a predetermined cut-off value for pressure is set and a pressure exceeding the cut-off value is detected, the judgment unit 6 judges that the risk of the patient developing surgery-related pressure disorders is high, and the judgment result can be notified to the surgeon or the like. As a method of notifying the result, for example, a warning sound may be emitted, or if the display unit 5 is provided, a warning may be displayed on the display. When the pressure measurement system 1 includes the judgment unit 6, there is an effect that it is not necessary to always monitor the measurement result.

[0031] Note that the above-mentioned optional additional matters are merely illustrative. Other optional additional matters may be combined as long as they are within the scope where the pressure measurement system 1 disclosed in the present application exhibits its effects. Also, some of the illustrated optional additional matters may be combined with some of the embodiments described in the pressure measurement system.

[0032] The pressure measurement system 1 disclosed in the present application exhibits the following effects. (1) The pressure measured by the pressure sensor array 2 can be calculated as the stress in the X and Y directions. And since the stress in the Z direction is not considered during the calculation, relatively small stresses in the X and Y directions related to the patient can also be measured. (2) The calculation unit 3 can calculate the X-direction shear stress, which is the difference in the X-direction stress of adjacent pressure-sensitive elements 22, and the Y-direction shear stress, which is the difference in the Y-direction stress of adjacent pressure-sensitive elements 22. In that case, based on the shear stress at the start of body position conversion, the risk of occurrence of surgery-related pressure disorders can be predicted with a high probability. Therefore, by converting the patient's body position before starting the surgery, the risk of the patient developing surgery-related pressure disorders can be reduced. (3) The calculation unit 3 can divide the region R2 so that the number of pressure-sensitive elements 22 included in one region R2 is two or more, and can vectorize the calculated X-direction and Y-direction stresses for each divided region R2. In that case, based on the vector at the start of body position conversion, the risk of occurrence of surgery-related pressure disorders can be predicted with a high probability. Therefore, by converting the patient's body position before starting the surgery, the risk of the patient developing surgery-related pressure disorders can be reduced. (4) The pressure measurement system 1 disclosed in the present application is formed compactly with the pressure sensor array 2 and the calculation unit 3. Therefore, by arranging the pressure sensor array 2 on an existing patient body position fixing device for lithotripsy surgery (for example, on the body pressure dispersion mat 41), the patient body position fixing device for lithotripsy surgery that can predict the risk of occurrence of surgery-related pressure disorders with a high probability can be improved.

[0033] (Embodiment of the patient body position fixing device for lithotripsy surgery) Next, a patient position fixing device for lithotomy surgery according to an embodiment will be described. The patient position fixing device for lithotomy surgery includes at least the pressure measurement system 1 according to any of the above-described embodiments. Since the pressure measurement system 1 has already been described in the above (embodiment of the pressure measurement system), detailed description thereof will be omitted. Further, the patient position fixing device for lithotomy surgery according to the embodiment is the same as a known patient position fixing device for lithotomy surgery except that it includes any of the embodiments of the pressure measurement system 1 disclosed in the present application. Therefore, detailed description of the patient position fixing device for lithotomy surgery will be omitted. Note that the patient position fixing device may optionally include a pressure sensor array 2 included in the pressure measurement system 1 and a body pressure dispersion mat 41 for dispersing the body pressure of the patient. The patient position fixing device for lithotomy surgery according to the embodiment has the same effect as the above-described pressure measurement system 1.

[0034] (Embodiment of the method for collecting pressure information) Next, a method for collecting pressure information according to an embodiment (hereinafter, may be simply referred to as "method") will be described. The method is performed using the patient position fixing device for lithotomy surgery described above. When performing surgery in the lithotomy position, the patient position fixing device is fixed on the operating table. The method includes (1) a step of arranging the patient so that the sacral region of the patient abuts on the substantially center of the pressure sensor array 2; (2) a posture changing step of changing the patient position fixing device on which the patient is arranged to the posture during lithotomy surgery; (3) a calculation step of calculating the pressure related to the pressure sensor array 2 after the posture changing step; and includes. (4) Then, when viewing the patient from the front, when the direction from the right side to the left side or from the left side to the right side of the patient is defined as the X direction, and when the direction from the head to the feet or from the feet to the head of the patient is defined as the Y direction when viewing the patient from the front, the calculation step divides the pressure sensor array 2 into predetermined regions and calculates the stress in the X direction and the Y direction in units of the divided regions.

[0035] (1) When implementing the step of placing the patient, the pressure sensor array 2 may be a single pressure sensor array 2, or a combination of a plurality of pressure sensor arrays 2. Also, when placing the patient, it is desirable to place the patient at approximately the center of the placed pressure sensor array 2.

[0036] (2) The posture change step changes the patient body position fixing device to the posture when performing surgery in the general lithotomy position. Although not limited, examples include lowering the patient's head by 15 degrees from the horizontal state and lowering the right side of the patient by about 15 degrees.

[0037] (3) The calculation content of the calculation steps (3) and (4) is the same as the calculation content of the calculation unit 3 in the above (embodiment of the pressure measurement system). Therefore, since it would be a duplicate description, detailed explanation is omitted.

[0038] The method for collecting pressure information according to the embodiment has the same effect as the above-described pressure measurement system 1.

[0039] Examples are given below to specifically describe the embodiments disclosed in this application. However, these examples are merely for the purpose of explaining the embodiments and do not represent a limitation or restriction of the scope of the invention disclosed in this application.

Example

[0040] [Example 1: Fabrication of a Patient Body Position Fixing Device for Lithotomy Surgery] For the pressure sensor array 2, a shear stress sensor (Nissha Co., Ltd., Kyoto, Japan) was used. Fig. 4 shows a photograph of the pressure sensor array 2 used. The pressure sensor array 2 is in the form of a flexible film, and 11 × 11 = 121 pressure-sensitive elements are arranged. The shear stress sensor can be selected in the following two modes: (1) a mode in which each pressure-sensitive element measures the stress in the actual gravitational direction and the X-Y direction perpendicular to the gravitational direction regardless of the orientation of the pressure sensor array 2; (2) a mode in which the X-Y-Z directions follow the inclination of the pressure-sensitive element when the pressure-sensitive element inclines from the set state after first setting the X-Y-Z directions. In the example, the mode described in (1) was implemented. Also, the value calculated by each pressure-sensitive element of the shear stress sensor is a corrected value obtained by calculating the pressures in various directions related to each pressure-sensitive element. The pressure sensor array 2 was placed on the body pressure dispersion mat 41 placed on the patient position fixing device (Murakami Medical Instruments Co., Ltd.) for lithotripsy surgery. The calculation unit 3 was fabricated by programming a personal computer so that the calculations described later can be performed.

[0041] [Example 2: Implementation of a method for collecting pressure information] (1) Experimental procedure The patient was placed on the patient position fixing device while considering that the sacral region of the patient abutted against the approximate center of the pressure sensor array 2 of the patient position fixing device prepared in Example 1. The number of target patients from whom pressure information was collected was 37 who underwent laparoscopic surgery in the lithotomy position. After performing position changes to 15 degrees of Trendelenburg position and 15 degrees of right lower Trendelenburg position, the pressure related to the pressure sensor array 2 was continuously monitored for pressure information. In various calculations described later, the calculations were performed based on the pressure data at 0 minutes, 30 minutes, 60 minutes, 90 minutes, and 120 minutes after the position change.

[0042] (2) Evaluation of surgical-related pressure disorders Immediately after the operation, multiple members of the surgical team evaluated the presence and degree of skin damage in the sacral region. Patients with skin erythema were defined as the PI group (hereinafter sometimes referred to as "PIG"). Also, the group not included in PIG may be referred to as "non-PIG"). The PI group includes patients with pressure ulcers (pressure-induced erythema) and reactive hyperemia (erythema that disappears after pressure-induced erythema). Pressure ulcers were classified based on the National Pressure Ulcer Advisory Panel (NPUAP). Treatment of pressure ulcers was continued based on international clinical practice guidelines.

[0043] (3) Calculation method The calculation unit 3 includes a region R1 that contains each of the 121 pressure-sensitive elements 22 included in the pressure sensor array 2 one by one, and as shown in FIG. 5, except for the pressure-sensitive elements in the first row, the sixth row, the eleventh row, and the first column, the sixth column, and the eleventh column, it is divided into one region R2 (a to d) so that 16 pressure-sensitive elements 22 are included. Also, as shown in FIG. 5, the direction from the right side to the left side of the patient is defined as the positive direction of the X direction (the reverse direction is the negative direction), and the direction from the head to the foot of the patient is defined as the positive direction of the Y direction (the reverse direction is the negative direction). For each region R1, the stress value in the X direction, the stress value in the Y direction, and the stress value in the Z direction were calculated. The vector components of each region R1 were obtained from the stress value in the X direction and the stress value in the Y direction. The horizontal shear stress was calculated as the difference between adjacent regions R1. Regarding the region R2, the average values of the stresses in the X direction and the Y direction of the 16 pressure-sensitive elements included in each region R2 were calculated as vectors.

[0044] (4) Various calculation results (a) Horizontal plane shear stress FIG. 6 shows the calculated horizontal plane shear stress. The horizontal plane shear stress is a value calculated by the following procedure. · X direction The difference in the X-direction stress of 121 (11×11) adjacent pressure-sensitive elements was calculated, and the average value of the differences in the X direction was obtained. In the example shown in FIG. 5, the number of differences per row in the X direction is 10. In this specification, the shear stress in the X direction means the difference in the X-direction stress of adjacent pressure-sensitive elements. FIG. 6 shows the average value of the shear stress in the X direction. ·Y direction The difference in the Y-direction stress of 121 (11×11) adjacent pressure-sensitive elements was calculated, and the average value of the differences in the Y direction was obtained. In the example shown in FIG. 5, the number of differences per column in the Y direction is 10. In this specification, the shear stress in the Y direction means the difference in the Y-direction stress of adjacent pressure-sensitive elements. FIG. 6 shows the average value of the shear stress in the Y direction.

[0045] As is clear from FIG. 6, both the shear stress in the X direction and the shear stress in the Y direction of PIG were significantly higher than those of non-PIG. Furthermore, the difference in the shear stress in the Y direction between PIG and non-PIG was greater than that in the X direction. Also, the shear stress in the X direction and the Y direction of PIG was higher immediately after the body position conversion. Therefore, by presetting the cut-off values of the shear stress in the X direction and the shear stress in the Y direction in many cases and readjusting the body position at an early stage after the body position conversion, the risk of developing surgery-related pressure disorders can be reduced.

[0046] FIG. 6 shows the average value of the shear stress in the X direction and the average value of the shear stress in the Y direction, while FIG. 7 shows the heat maps of the calculated individual shear stresses in the X direction and the Y direction. The positional relationship of the heat maps shown in FIG. 7 is the same as that in FIG. 5, and the upper side of each heat map corresponds to the head side of the patient, the lower side corresponds to the foot side of the patient, the left side corresponds to the right side of the patient, and the right side corresponds to the left side of the patient. As is clear from the part particularly indicated by 〇 in the heat map of FIG. 7, in PIG, high-shear-stress sites are concentrated on the right side of the sacrum both in the X direction and the Y direction, and it was confirmed that the difference between PIG and non-PIG is greater in the Y direction.

[0047] (b) Vector Figure 8 shows the vectors of each calculated region R2(a, b, c, d). As is clear from Figure 8, after the body position transformation, for the vectors at 0 minutes, 30 minutes, 60 minutes, 90 minutes, and 120 minutes, in any region, PIG and non-PIG showed different directions. In particular, in regions c and d, the vector directions of PIG and non-PIG were significantly different at any time from 0 minute to 120 minutes. And in d, when the vectors were divided into four sections by ±, PIG and non-PIG belonged to different sections respectively. From the above results, it was confirmed that there was a significant difference between PIG and non-PIG even when calculating by combining the stresses in the X and Y directions.

[0048] Figure 9 shows only the vector at 0 minute after the body position transformation among the vectors of PIG and non-PIG in Figure 8. Also shown is the cosine similarity when comparing the vectors of each region a - d. Note that the cosine similarity is a measure representing the similarity of "how similar two vectors are", and it is the cosine value of the angle formed by two vectors. If the value of the cosine similarity is 1, it means the two vectors are "similar", and if it is -1, it means they are "dissimilar". As shown in Figure 9, for a vs d, b vs d, and c vs d, the cosine similarity of PIG was negative. From this result, by calculating and comparing vectors from the stresses in the X and Y directions of each region immediately after the body position transformation and readjusting the body position at an early stage after the body position transformation, the risk of developing surgery-related pressure disorders can be reduced.

[0049] (c) Z direction Figure 10 shows the heat map of the stress in the Z direction (gravity direction) measured by 121 pressure-sensitive elements. When collecting data, the patient's head was lowered by 15 degrees from the horizontal state, and the patient's right side was lowered by about 15 degrees. As is clear from Figure 10, with the passage of time, in PIG, the pressure on the right side of the patient increased. On the other hand, in non-PIG, no extreme difference was seen in the pressure distribution.

[0050] FIG. 11 is a graph in which the stress in the Z direction is averaged in units of regions a to d. As is clear from FIG. 11, it was confirmed that in the PIG, the stress on the right side of the patient (regions a and c) increases with time, while on the left side of the patient (regions b and d), there is almost no change. From the above results, it was confirmed that by observing the pressure in the Z direction over time and looking at the change information of the pressure distribution, the risk of developing surgery-related pressure disorders can be predicted.

Industrial Applicability

[0051] The pressure measurement system, the patient position fixing device for lithotripsy surgery, and the method for collecting pressure information disclosed in this application can reduce the risk of developing surgery-related pressure disorders when operating on a patient. Therefore, it is useful for the medical device industry.

Explanation of Signs

[0052] 1... Pressure measurement system, 2... Pressure sensor array, 21... Substrate, 22... Pressure-sensitive element, 3... Arithmetic unit, 4... Patient position fixing device, 41... Body pressure dispersion mat, 5... Display unit, 6... Judgment unit, R1, R2... Regions

Claims

1. A pressure measurement system for measuring the pressure applied to the sacrum of a patient during surgery in the lithotomy position, the pressure measurement system comprising: a pressure sensor array; a calculation unit that calculates measurement values of the pressure around the sacrum of the patient obtained from the pressure sensor array; and the pressure sensor array is configured such that: when the Z-direction is defined as the direction of gravity, the X-direction is defined as the direction perpendicular to the direction of gravity, and the Y-direction is defined as the direction perpendicular to both the Z-direction and the X-direction, when the sacrum of the patient comes into contact, the stress in the X-direction and the Y-direction can be measured; the calculation unit is configured such that: when viewing the patient from the front, the X-direction is defined as the direction from the right side to the left side or from the left side to the right side of the patient; when viewing the patient from the front, the Y-direction is defined as the direction from the head to the feet or from the feet to the head of the patient; the pressure sensor array is divided into predetermined regions, and the stress in the X-direction and the Y-direction is calculated for each of the divided regions; a pressure measurement system.

2. A plurality of pressure-sensitive elements are arranged in the pressure sensor array, and the calculation unit divides the regions such that the number of pressure-sensitive elements included in one region is 1. The pressure measurement system according to claim 1.

3. A plurality of pressure-sensitive elements are arranged in the pressure sensor array, and the calculation unit divides the regions such that the number of pressure-sensitive elements included in one region is 2 or more, and the number of the divided regions is an even number. The pressure measurement system according to claim 1.

4. The calculation unit calculates the vectors of the stress in the X-direction and the Y-direction for each of the divided regions. The pressure measurement system according to claim 3.

5. the pressure sensor array can measure the stress in the Z-direction, and the calculation unit, in addition to calculating the stress in the X-direction and the Y-direction for each of the divided regions, calculates the stress in the Z-direction for each of the divided regions. The pressure measurement system according to claim 1.

6. further comprising a display unit that displays the results calculated by the calculation unit. The pressure measurement system according to any one of claims 1 to 5.

7. further comprising a determination unit that determines whether the patient is likely to develop surgery-related pressure disorder based on the results calculated by the calculation unit. The pressure measurement system according to any one of claims 1 to 5.

8. A patient position fixing device for lithotomy surgery, comprising the pressure measurement system according to any one of claims 1 to 5.

9. A method for collecting pressure information related to a pressure sensor array during surgery at the lithotripsy site using a pressure measurement system, comprising: The pressure measurement system includes: a pressure sensor array; a calculation unit that calculates measured values of pressure around the sacrum of a patient obtained from the pressure sensor array; and The method includes: a step of arranging the patient so that the sacrum of the patient abuts on the approximate center of the pressure sensor array; a posture changing step of changing the patient posture fixing device on which the patient is arranged to the posture during surgery in the lithotripsy position; a calculation step of calculating the pressure related to the pressure sensor array after the posture changing step; and defining the gravity direction as the Z direction, the direction perpendicular to the gravity direction as the X direction, and the direction perpendicular to the Z direction and the X direction as the Y direction; defining the direction from the right side to the left side or from the left side to the right side of the patient as the X direction when viewing the patient from the front; when defining the direction from the head to the feet or from the feet to the head of the patient as the Y direction when viewing the patient from the front, the calculation step includes: dividing the pressure sensor array into predetermined regions, and calculating the stress in the X direction and the Y direction in units of the divided regions. Method

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