Epidural simulator

Abstract

The description pertains to an epidural simulator 100 which is capable of simulating variable depths from the patient's skin to the epidural space to represent variable patient anatomy. The epidural simulator is comprised of a base plate, a back screen, a ligament holder and an adjustment mechanism. The back screen has at least one hole sized to allow an epidural needle to pass therethrough. The back screen is coupled to said base plate and oriented in a generally parallel fashion to the ligament holder. The ligament holder is coupled to the base plate and configured to secure a removable simulated ligament. It is configured in such a manner to expose at least part of the removable simulated ligament on a first side of the ligament holder between the ligament holder and the back screen. The distance between the back screen and the ligament holder is variable by means of the adjustment mechanism to mimic different patient body types.

Description

EPIDURAL SIMULATORFIELD OF THE INVENTION

[0001] The invention pertains to a device for simulating tissue penetrated by a needle. More specifically, the invention pertains to a device for simulating tissue penetrated by a needle during an epidural procedure.BACKGROUND

[0002] Current epidural simulators are effective at simulating tissue leading up to the ligamentum flavum and the epidural space itself. Typical simulators are composed of various materials such as foam or silicone to represent the tissue that is penetrated by a needle during the epidural procedure. However, when conducting epidurals in a clinical setting, clinicians are presented with a population of patients who have variable height, weight, and body mass index (BMI). As a result, the depth to the epidural space can vary significantly from patient to patient. Research suggests that the skin to epidural space distance is less than 33 mm for the 2.5thpercentile and greater than 56 mm for the 97.5thpercentile of BMI. There are substantially different user needs and human factors present for the different depths, as the needle may be anywhere from fractionally inserted to fully inserted to the needle hub, impacting how a user may be able to hold and interact with devices attached to that needle. Training on both shallow and deep penetration depths is important as there are different user needs for the clinician performing the procedure.When inserting an epidural needle into a patient, it is important that the needle tip is placed within the epidural space. This can be challenging since the width of the epidural space is typically 5 mm or less. If the needle is advanced too far beyond the epidural space it can result in puncturing of the dura, the outermost layer of protection around the spinal cord. This can result in serious conditions such as painful headaches or paralysis. However, if the needle is not advanced far enough such that the needle tip has not yet entered the epidural space, the medication cannot be administered properly. This delays the procedure and results in prolonged discomfort for the patient. For these reasons it is important that the clinician has access to sufficient training, preferably using an epidural simulator. Existing epidural simulators used to train clinicians on preforming an epidural procedure are limited and have only one depth to the simulated epidural space. Since the depth from a patient’s skin to the epidural space will vary based on their body shape and composition, these simulators are of limited use in trainingclinicians for a variety of patient body types. There remains a need for an epidural simulator that allows for variability in the depth of the epidural space.SUMMARY OF THE INVENTION

[0003] The description pertains to an epidural simulator 100 which is capable of simulating variable depths from the patient’s skin to the epidural space to represent variable patient anatomy. The epidural simulator is comprised of a base plate, a back screen, a ligament holder and an adjustment mechanism. The back screen has at least one hole sized to allow an epidural needle to pass therethrough. The back screen is coupled to said base plate and oriented in a generally parallel fashion to the ligament holder. The ligament holder is coupled to the base plate and configured to secure a removable simulated ligament. It is configured in such a manner to expose at least part of the removable simulated ligament on a side of the ligament holder parallel to the ligament holder and the back screen. The distance between the back screen and the ligament holder is variable by means of the adjustment mechanism to mimic different patient body types.

[0004] One embodiment pertains to an epidural simulator comprising a base plate, and a back screen having at least one hole sized to allow an epidural needle to pass therethrough. The back screen is coupled to the base plate and oriented in a generally parallel fashion to a ligament holder. The ligament holder is coupled to the base plate and configured to secure a removable simulated ligament. The ligament holder is configured to expose at least part of the removable simulated ligament on a first side between the ligament holder and the back screen. The epidural simulator also comprises an adjustment mechanism for varying the distance between the ligament holder and the back screen to simulate a range of depths to an epidural space.

[0005] In a further embodiment, the adjustment mechanism is a linear adjustment mechanism which allows for linear movement of the back screen relative to the ligament holder.

[0006] In yet a further embodiment, the back screen further comprises one or more holes to allow for insertion and removal of a needle.

[0007] In yet a further embodiment, the back screen is configured to mimic the size and shape of a human back.

[0008] In yet a further embodiment, the epidural simulator further comprises a simulated ligament. The simulated ligament is sized to be retained by the ligament holder, yet removable, and is made of an elastomer that has a density similar to that of a human ligamentum flavum.

[0009] In yet a further embodiment, the simulated ligament restricts the flow of fluid through a needle when the needle tip is occluded by the simulated ligament.

[0010] In yet a further embodiment, the epidural simulator further comprises a removable spinous process component that simulates the geometry of the spinous processes and is removably coupled to the ligament holder between the back screen and the ligament holder.

[0011] In yet a further embodiment, the ligament holder is stationary relative to the base plate and the adjustment mechanism is coupled to the back screen to move the back screen relative to the base plate.

[0012] In another embodiment, the back screen is stationary relative to the base plate and the adjustment mechanism is coupled to the ligament holder to move the ligament holder relative to the back screen.

[0013] In yet a further embodiment, the epidural simulator contains the simulated ligament described in as well as additional simulated tissue layers such as intermediary ligaments, muscle tissue, and subcutaneous tissue, with properties similar to that of human tissue.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The features of the invention will become more apparent in the following detailed description in which reference is made to the appended drawings wherein:

[0015] Figure 1 is a perspective view of one embodiment of the epidural simulator;

[0016] Figure 2a is a sideview of one embodiment of the epidural simulator with a depth configuration set to mimic a large patient;

[0017] Figure 2b is a sideview of one embodiment of the epidural simulator with a depth configuration set to mimic a medium-sized patient;

[0018] Figure 2c is a sideview of one embodiment of the epidural simulator with a depth configuration set to mimic a small patient;

[0019] Figure 3a is a front perspective view of one embodiment of the epidural simulator with a depth configuration set to mimic a larger patient;

[0020] Figure 3b is a front perspective view of one embodiment of the epidural simulator with a depth configuration set to mimic a smaller patient;

[0021] Figure 4 is a perspective view of a second embodiment of the epidural simulator wherein the plane of the back screen is generally parallel to the plane of the base plate; and

[0022] Figure 5 is a side view of the second embodiment of the epidural simulator wherein the plane of the back screen is generally parallel to the plane of the base plate.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Figure 1 shows a preferred embodiment of an epidural simulator 100. The epidural simulator 100 is capable of simulating variable depths from the patient’s skin to the epidural space to represent variable patient anatomy.

[0024] The epidural simulator 100 includes an elastomer layer 102 to simulate the ligamentum flavum. This layer is resistant to fluid flow to simulate resistance to injecting air or saline when the tip of the needle 103 is inserted into the patient’s ligament. The simulated ligament layer 102 can be removed and replaced with a fresh piece of material after it degrades over repeated uses. Immediately anterior to the simulated ligament 102 is a region open to air that simulates the epidural space. This is a region of low or negligible resistance to fluid flow. In one embodiment the epidural space is simply air on the anterior side of the simulated ligament 102. Alternatively, the epidural space could be simulated by a physical component, such as, but not limited to, tubing or other suitable structure which has low or negligible resistance to fluid flow. The simulated ligament 102 is supported by a rigid ligament holder 104 connected to a rigid base plate 106. The base plate 106 can optionally connect to a securement mechanism 108, such as a clamp or other suitable device known to a person skilled in the art, to secure the epidural simulator 100 onto a suitable surface, such as a table. The device has a back screen 110 to simulate the patient’s back. The back screen 110 mounts onto the base plate 106. In the preferred embodiment, the back screen 110 mounts onto the base plate 106 with an adjustable connection 112 to allow for varying the distance from the simulated patient’s back to the simulated epidural space. In the example shown in the figures, the adjustable connection 112 uses two sliders with thumb screws to fasten the back screen 110 to the base plate 106 at any location along the slider slot 114. Alternative mechanisms could be used to secure the back screen 110 to the base plate 106 at various distances from the simulated ligament 102. The ability to mount the back screen 110 at varying distances from the simulated ligament 102 simulates different distances from skin to epidural space, as would be found in different patients. The back screen 1 10 has holes 116 to allow for inserting the needle 103 through the back screen 110 and into the simulated ligament 102. One embodiment of the epidural simulator 100 includes a removable rigid spinous processes component 118 to simulate the spinous processes as shown in figures 2a and 2b. The spinous processes component 118 attaches posterior to the simulated ligament 102 and anterior to the back screen 110. In the preferred embodiment, the spinous processes component 118 is removable to allow for increased visibility of the simulated ligament 102 or added to enhance realism. While many different attachment mechanisms wouldbe known to a person skilled in the art, in a preferred embodiment, magnets are used to attach the spinous processes 118 to the ligament holder 104. Alternatively, the spinous processes 118 could be held within the ligament holder 104, between the interior wall of the posterior side of the ligament holder and the simulated ligament 102. It can be appreciated that a variety of other attachment mechanisms would be known to a person skilled in the art.

[0025] As discussed above, the epidural simulator 100 can be adjusted to simulate different sizes of patients. Figures 2a and 3a show the epidural simulator 100 set to simulate a large patient. In this configuration, the ligament holder 104 is spaced substantially from the back screen 110. In the preferred embodiment, this is facilitated by loosening the thumb screw 112 and sliding the back screen 110 posteriorly along slider slot 114. Since the thumb screw 112 is coupled to the back screen 110, the back screen also moves posteriorly with respect to the ligament holder 104. Figures 2c and 3b show the epidural simulator 100 adjusted for a small patient. In this configuration, the thumb screw 112 and coupled back screen 110 are moved anteriorly along the slider slot 114. This brings the back screen 110 closer to the ligament holder 104. For completeness, figure 2b shows the epidural simulator 100 configured to simulate a medium sized patient.

[0026] In one embodiment, the back screen 110 is configured with slots 120 which slide along guide rails 122 to maintain the relative angle of the back screen 110 on the base plate 106. This holds the orientation of the back screen 110 generally parallel to the ligament holder 104.

[0027] While the preferred embodiment shown in the figures shows the back screen moving relative to the base plate, it can be appreciated by a person skilled in the art, that the same effect could be achieved if the back screen 110 was stationary and the ligament holder 104 moved relative to the back screen 110. Furthermore, it would be possible that both the back screen 110 and the ligament holder 104 could be moveable.

[0028] In another embodiment shown in figures 4 and 5, the plane of the ligament holder 104 and the plane of the back screen 110 are oriented generally parallel to the plane of the base plate 106. This embodiment is particularly advantageous for physicians that prefer to administer the needle vertically from above. In this embodiment, the base plate 106 is configured to be clamped using clamp 108 to a flat surface, such as a table. The back screen 110 is coupled to the baseplate 106 to allow for movement of the back screen 110 in a vertical direction toward and away from the ligament holder 104. While various methods to accomplish this variation in spacing between the back screen 110 and the baseplate 106 would be known to a person skilled in the art, in the preferred embodiment shown in the figures, the back screen 110 is configured with a receiving plate 124. The receiving plate 124 has a threaded hole to receive a threaded bolt coupled to knob 112. The threaded bolt coupled to knob 112 can be moved vertically within slot 114. When the knob 112 is tightened, the location of the back screen is held in position. Ascan be appreciated by the figures, this height adjustment mechanism is preferably on both sides of the back screen 110.

[0029] Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto.

Claims

What is claimed is:1 . An epidural simulator comprising: a base plate; a back screen having at least one hole sized to allow an epidural needle to pass therethrough; said back screen coupled to said base plate and oriented in a generally parallel fashion to a ligament holder; the ligament holder coupled to said base plate and configured to secure a removable simulated ligament; the ligament holder configured to expose at least part of the removable simulated ligament on a first side between the ligament holder and the back screen; and an adjustment mechanism for varying the distance between said ligament holder and said back screen to simulate a range of depths to an epidural space.

2. The epidural simulator as claimed in claim 1 wherein the adjustment mechanism is a linear adjustment mechanism which allows for linear movement of the back screen relative to the ligament holder.

3. The epidural simulator as claimed in claim 1 wherein the back screen further comprises a grid of holes to allow for insertion and removal of a needle.

4. The epidural simulator as claimed in claim 3 wherein the back screen is configured to mimic the size and shape of a human back.

5. The epidural simulator as claimed in claim 3 further comprising a simulated ligament; the simulated ligament is sized to be retained by said ligament holder, yet removable; and wherein the simulated ligament is made of an elastomer that has a density similar to that of a human ligamentum flavum.

6. The epidural simulator of claim 5 wherein the simulated ligament restricts the flow of fluid through a needle when the needle tip is occluded by the simulated ligament.

7. The epidural simulator of claim 1 further comprising a removable spinous processes component that simulates the geometry of the spinous processes and is removably coupled to the ligament holder between said back screen and said ligament holder.

8. The epidural simulator of claim 2 wherein the ligament holder is stationary relative to the base plate and the adjustment mechanism is coupled to the back screen to move the back screen relative to the base plate.

9. The epidural simulator of claim 2 wherein the back screen is stationary relative to the base plate and the adjustment mechanism is coupled to the ligament holder to move the ligament holder relative to the back screen.

10. The epidural simulator of claim 2 wherein the plane of the ligament holder and the plane of the back screen are generally perpendicular to the plane of the base plate.11 . The epidural simulator of claim 2 wherein the plane of the ligament holder and the plane of the back screen are generally parallel to the plane of the base plate.

12. The epidural simulator of claim 6 with additional simulated tissue layers such as intermediary ligaments, muscle tissue, and subcutaneous tissue. The simulated tissue layers have properties similar to that of human tissue.

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