The field of the application relates to devices and methods for accessing a space in a body, and more particularly, for devices and methods for accessing epidural space.
Epidural anesthesia blocks pain sensation at nerve roots that branch directly from the spinal cord by bathing them with local anesthetic agents or opioids delivered to the epidural space, a small region adjacent to the outer protective covering of the spinal cord. This route of drug delivery provides an effective method for pain control during childbirth, major surgery, and chronic back pain as well as many other types of pain that may be debilitating in nature or affect a patient's quality of life.
Accessing the epidural space to administer anesthetic remains challenging due to its small size and proximity to the spinal cord and risk of complications, such as dural puncture, epidural vein puncture, and failure of pain control. Existing technique for accessing the epidural space involves using a sharp needle to pierce through the ligamentum flavum. Once the distal tip of the needle reaches the epidural space, a separate catheter is then inserted through the needle to reach the epidural space, thereby allowing fluid to be delivered to the epidural space using the catheter. Such technique can lead to inadvertent puncture of the dura or damage to the tissue in the area of the spinal column as well as failure of pain control. In addition, inserting a separate catheter through the needle may lead to bending or kinking of the catheter, is inconvenient, and may complicate the process. Furthermore, such existing technique requires significant training to proficiency.
For the foregoing reasons, Applicants of the subject application determine that it would be desirable to have a new device and method for accessing the epidural space.
In accordance with some embodiments, a device for use in a process that involves accessing a bodily space includes a shaft having a proximal end, a distal end, and a lumen extending between the proximal and distal ends of the shaft, a flexible tube having a proximal end, a distal end, and a channel extending between the proximal and distal ends of the flexible tube, wherein at least a part of the tube is located in the lumen of the shaft, and a tissue engagement device coupled to the distal end of the flexible tube, wherein the shaft is detachably coupled to the tissue engagement device.
In accordance with other embodiments, a device for use in a process that involves accessing a bodily space includes a flexible tube having a proximal end, a distal end, and a channel extending between the proximal and distal ends of the flexible tube, and a tissue engagement device coupled to the distal end of the flexible tube, wherein the tissue engagement device comprises a body with threads and a port located on the body, the port being in fluid communication with the channel of the flexible tube.
In accordance with other embodiments, a method for use in a process that involves accessing a bodily space includes inserting a tissue engagement element into a body, the tissue engagement element coupled to a shaft, operating the shaft to cause the tissue engagement element to engage with tissue, decoupling the shaft from the tissue engagement element, pulling the shaft proximally to expose a flexible tube inside the body, and using the flexible tube to deliver fluid or an object into the body.
In accordance with other embodiments, a method for use in a process that involves accessing a bodily space includes inserting a tissue engagement element into a body, the tissue engagement element coupled to a flexible tube, inserting the tissue engagement element at least partially into ligamentum flavum tissue to anchor the tissue engagement element against the ligamentum flavum tissue, and using the flexible tube to deliver fluid or an object into the body.
Other and further aspects and features will be evident from reading the following detailed description of the embodiments, which are intended to illustrate, not limit, the invention.
The drawings illustrate the design and utility of embodiments, in which similar elements are referred to by common reference numerals. These drawings are not necessarily drawn to scale. In order to better appreciate how the above-recited and other advantages and objects are obtained, a more particular description of the embodiments will be rendered, which are illustrated in the accompanying drawings. These drawings depict only typical embodiments and are not therefore to be considered limiting of its scope.
Various embodiments are described hereinafter with reference to the figures. It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the embodiments. They are not intended as an exhaustive description of the invention or as a limitation on the scope of the invention. In addition, an illustrated embodiment needs not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated.
The tissue engagement element 30 has a distal end 32 with a blunt tip, and a proximal end 34 configured to detachably couple to the distal end 24 of the shaft 22. The tissue engagement element 30 also includes screw-type threads 36 configured for drilling into tissue. The tissue engagement element 30 further includes an opening 38 that is in fluid communication with the lumen 56 of the flexible tube 50.
During use, in one mode of operation, the shaft 22 may be coupled to the tissue engagement element 30 by the slot-protrusion arrangement, and the shaft 22 may be used to transmit torque applied at a proximal end to turn the tissue engagement element 30. In another mode of operation, the shaft 22 may be decoupled from the tissue engagement element 30 to expose the flexible tube 50. The method of using the device 10 will be discussed in further detail below.
As discussed, the shaft 22 may be coupled to the tissue engagement element 30 for turning the tissue engagement element 30. In some embodiments, the proximal end 26 or the handle 40 of the shaft 22 may be detachably coupled to a proximal end 54 of the flexible tube 50 as well. Such configuration allows the flexible tube 50 to be rotated together with the shaft 22.
In the above embodiments, the protrusions 82a, 82b are illustrated as being at the inner wall of the handle 40. In other embodiments, the protrusions 82a, 82b may be at the inner wall of the shaft 22 (e.g., at the proximal end 26 of the shaft 22).
To access the epidural space 160, the patient is positioned either seated or on his/her side, and is instructed to flex the back outward to maximize the spacing between the outer vertebral components. The spinal processes 178 are palpated, and the interlaminar space is estimated. The doctor then uses the introducer sheath 12, with the tissue engagement element 30 housed within it, to puncture the patient's skin 180 (
Next, the doctor then advances the handle 40 distally to push the tissue engagement element 30 out of the distal opening at the introducer sheath 12, and the doctor then turns the handle 40 to rotate the tissue engagement element 30, thereby drilling the tissue engagement element 30 into the ligamentum flavum 166 (
As the doctor rotates the handle 40, the doctor also applies pressure at the plunger 62 of the fluid source 60. While the tissue engagement element 30 is being advanced through the ligamentum flavum 166, the opening 38 is inside the layer of the ligamentum flavum 166, which prevents fluid from being delivered out of the opening 38. Thus, the doctor will sense a relatively high pressure at the plunger 62 while the tissue engagement element 30 is being drilled through the ligamentum flavum 166. Alternatively, a pressure application system may be used to automatically apply the pressure while the tissue engagement element 30 is being drilled through the ligamentum flavum 166. In such case, the pressure application system may include a pressure for sensing the pressure that is being applied.
As shown in
Next, the shaft 22 is decoupled from the tissue engagement element 30 (e.g., by pulling proximally relative to the tissue engagement element 30), and the shaft 22 is removed from the rest of the device 10 (
As illustrated in the above embodiments, having the flexible tube 50 built into the device 10 is advantageous because it obviates the need to have a separate delivery catheter, and it obviates the need to have the extra step of inserting the delivery catheter through the shaft 22 to reach the opening 38 of the tissue engagement element 30. This, in turn, eliminates the risk of bending and/or kinking of the flexible tube, misplacement of the catheter outside of the epidural space, and risk of infection (because one less piece of equipment is needed to be inserted into the patient). Also, as illustrated in the above embodiments, devices and methods described herein facilitate controlled entry into the epidural space 160 by controllably advancing the tissue engagement element 30 into the ligamentum flavum 166. This is advantageous because it reduces the risk of injuring the dura. Also, the blunt distal tip at the tissue engagement element 30 is advantageous because it further reduces the risk of injuring the dura.
In the above embodiments, the flexible tube 50 is described as being fixedly secured to the tissue engagement element 30. In other embodiments, the flexible tube 50 may not be fixedly secured to the tissue engagement element 30. Instead, the flexible tube 50 may be rotatably coupled to the tissue engagement element 30.
In further embodiments, the device 10 may optionally include a coupler 200 for coupling the shaft 22 and the flexible tube 50 to the fluid source 60 (
It should be noted that the configuration of the device 10 is not limited to the examples described herein, and that the device 10 may have other configurations in other embodiments. For example, in other embodiments, the flexible tube 50 may be configured (e.g., sized and/or shaped) to slidably couple to the tissue engagement element 30. In one implementation, the distal portion of the flexible tube 50 may be configured to have a frictional fit against an inner wall of the tissue engagement element 30. Such configuration allows the flexible tube 50 to couple to the tissue engagement element 30, while also allowing the flexible tube 50 to translate axially (e.g., distally or proximally) relative to the tissue engagement element 30. During use, after the tissue engagement element 30 has been anchored relative to the ligamentum flavum 166, the flexible tube 50 may be advanced distally so that its distal end 52 exits out of the opening 38 at the tissue engagement element 30. The flexible tube 50 may then be used to deliver substance, such as pain medication, agent, drug, etc., into the body. In further embodiments, the inner wall of the tissue engagement element 30 may have one or more protrusions for mating with respective one or more elongated grooves on the exterior surface of the flexible tube 50. The groove(s) extend longitudinally along at least a portion of a length of the tube 50, thereby allowing the flexible tube 50 to be slidably coupled to the tissue engagement element 30. In alternative embodiments, the protrusion(s) may be on the exterior surface of the flexible tube 50, and the groove(s) may be defined on the inner wall of the tissue engagement element 30.
In addition, in further embodiments, the tissue engagement element 30 does not need to have the configuration described previously, and the tissue engagement element 30 may have any configuration as long as it can be inserted into ligamentum flavum tissue 166, and/or anchor itself against the ligamentum flavum 166.
Also, in other embodiments, the device 10 may not include the handle 40. Instead, the proximal portion of the shaft 22 may be used as a handle. In addition, in other embodiments, the device 10 may further include a handle coupled to the proximal end 16 of the introducer sheath 12. In further embodiments, the device 10 may not include the introducer sheath 12. In such cases, the tissue engagement element 30 and the shaft 22 may be used to puncture the patient's skin to access the epidural space 160. In addition, in other embodiments, the proximal end 54 of the flexible tube 50 may include two ports, wherein one port is for fluid communication with the fluid source 60 (e.g., a syringe carrying saline) for use during advancement of the tissue engagement element 30, and the other port is for fluid communication with another fluid source (e.g., fluid source 90) for delivering fluid, such as pain medication, to the patient after the tissue engagement element 30 has been anchored against the ligamentum flavum 166. In such cases, the proximal end 54 of the flexible tube 50 may include a valve control for selectively allowing fluid flow to the distal end 52 from either one of the two fluid sources.
A person skilled in the art will appreciate the foregoing as only illustrative of the various embodiments, and that various modifications may be made to both the epidural space accessing devices and the methods presented without departing from the scope and spirit of the invention.
This invention was made with Government support under Grant No. 0848916 awarded by the National Science Foundation. The Government has certain rights in this invention.