Patent Application
20070203516
The present invention relates to a medical device and method. More particularly, the present invention relates to an apparatus and method for creating an opening or orifice in a septum (or membrane). Specifically, the invention discloses an apparatus and methods for using the apparatus to make an opening in the membrane floor of a ventricle in the brain during an endoscopic third ventriculostomy (ETV) procedure.
Non-communicating hydrocephalus is a condition that results in the enlargement of the ventricles caused by abnormal accumulation of cerebrospinal fluid (CSF) within the cerebral ventricular system.
In non-communicating hydrocephalus there is an obstruction at some point in the ventricular system. The cause of non-communicating hydrocephalus usually is a congenital abnormality, such as stenosis of the aqueduct of Sylvius, congenital atresia of the foramina of the fourth ventricle, or spina bifida cystica. There are also acquired versions of hydrocephalus that are caused by a number of factors including subarachnoid or intraventricular hemorrhages, infections, inflammation, tumors, and cysts.
The main treatment for hydrocephalus is venticuloperitoneal (VP) shunts. The VP shunts are catheters that are surgically lowered through the skull and brain. The VP shunts are then positioned in the lateral ventricle. The distal end of the catheter is tunneled under the skin and positioned in the peritoneal cavity of the abdomen, where the CSF is absorbed.
However, the VP shunts have an extremely high failure rate, e.g., in the range of 30 to 40 percent. Failure includes clogging of the catheter, infection, and faulty pressure valves or one-way valves.
Another relatively newly re-introduced treatment for non-communicating hydrocephalus is the procedure known as an endoscopic third ventriculostomy (ETV). This procedure involves forming a burr hole in the skull. A probe is passed through the burr hole, through the cerebral cortex, through the underlying white matter and into the lateral and third ventricles. The probe is then used to create (fenestrate) an opening in the floor of the third ventricle and underlying membrane of Lillequist.
To verify that the procedure is successful, i.e., that an opening is formed in the floor of the third ventricle and the underlying membrane of Lillequist, the patient is observed with magnetic resonance imaging (MRI) after the puncture. The MRI is used to verify a flow of CSF through the opening in the floor of the third ventricle.
If the MRI is unable to detect the flow of CSF, a determination is made that an opening in the floor of the third ventricle was not formed, and the ETV procedure is repeated.
Since the MRI is typically located at a separate location, the ETV procedure typically requires the patient to be moved from location to location. This, in turn, increases the procedure time as well as the expense and complexity of the ETV procedure.
After the formation of an opening is verified, a catheter delivered balloon can be used to enlarge the opening. Even after successfully forming an opening in the floor of the third ventricle, the opening sometimes closes, typically within two weeks to two months after the ETV procedure. In this event, the patient will have to undergo another ETV procedure or risk serious injury or death. One potential reason for closing is that when the opening is fenestrated, it is formed as more of a rip such that the edges of the opening can appose and seal the opening closed.
Thus it would be beneficial to have a device and method for forming openings in the floor of the third ventricle that would allow a clinician to know that the opening had been formed without having to move the patient to a separate location for an MRI procedure. Such a device that would reduce the potential for the edges of openings to heal back together would be advantageous.
It should be noted that the term distal end as used herein shall be taken to mean the end of the element being described that is furthest from a clinician who will be operating the apparatus. Stated another way, the distal end of an element is the first end of the element that will be inserted into the body of a patient when an apparatus of the type disclosed here is being used to remove a section of tissue from a tissue membrane in a body.
The current invention discloses preferred embodiments of an apparatus for creating an opening in a tissue membrane and methods for using the apparatus to create an opening in the floor of the third ventricle of a brain. Some embodiments of the apparatus comprise a cutting device that can include a cutting element and a resisting element located on the ends of elongate members. The cutting device can be manipulated so that the cutting element and resisting element are on opposite sides of a tissue membrane. Alternate preferred embodiments of the apparatus do not include a resisting element.
In some embodiments of the apparatus, the cutting device may be configured to tear a section of tissue from a tissue membrane rather than to cut the section away. However, all embodiments of the apparatus disclosed herein are intended to be used to create a hole in a tissue membrane by removing a portion of tissue from the membrane. This tissue may ultimately be removed from the body of a patient.
The cutting device is delivered to a tissue membrane using an elongate delivery device that can be routed through a working lumen in an endoscopic probe. The delivery device can also access the tissue membrane via means other than an endoscopic probe.
In one embodiment of a method for using the devices disclosed herein, a device is delivered to a location adjacent the floor of a third ventricle in a brain via and endoscopic probe through a burr hole in a skull. In another embodiment of a method for using the devices disclosed herein, the devices can be delivered to the floor of a third ventricle via a catheter that is navigated through the spinal subarachnoid space. The devices described herein can then be used to create an opening in the ventricle from the subarachnoid space side of the ventricular floor.
Embodiments of the invention can include a vacuum or suction lumen in the delivery device and a vacuum or suction source for stabilizing the tissue membrane relative to the apparatus and/or for removing sections of portions that are cut from the membrane (throughout this document, the term “vacuum” should be taken to mean “vacuum or suction”). The vacuum source can be any mechanical, electrical, or manually operated source that provides sufficient force for tissue stabilization relative to the cutting element (i.e., sufficient to force the tissue against a cutting edge of the device) and/or sufficient force to secure a portion of the tissue membrane for withdrawal from a body.
The present invention discloses methods and devices for creating an opening in the floor of a ventricle for performing an endoscopic third ventriculostomy. The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings, which are not to scale. The detailed description and drawings are merely illustrative of the invention, rather than limiting the scope of the invention being defined by the appended claims and equivalents thereof.
The invention will now be described in detail below by reference to the drawings, wherein like numbers refer to like structures. Referring to
The procedure can also include measuring the flow of CSF through the opening with a flow sensor, or using a pressure sensor to measure the pressure gradient across the opening. While not depicted in the drawings, the devices described herein can also include a lumen for injecting a contrast medium into the third ventricle such that a clinician can use fluoroscopy or other imaging modalities to determine if there is flow of CSF. The contrast injection lumen can be a separate lumen in the delivery devices described herein, or the contrast medium can be injected through a vacuum lumen or other lumen in the apparatus.
More particularly,
It should be noted that for the purposes of this document, discussions and descriptions of creating openings in the floor of the third ventricle or removing sections of the ventricle floor are meant to include creating openings in or removing sections of the membrane of Lillequist. Thus any such discussion referring to the floor of a third ventricle should be read to include the underlying membrane of Lillequist regardless of whether the membrane is specifically referenced in the discussion or description.
Referring to
The cutting device is delivered to the third ventricle inside of an elongated delivery device 220. The delivery device depicted in
In some embodiments of the invention, the delivery device can be inserted into a working lumen of an endoscopic third ventriculostomy probe such as the one shown in
The first elongate member 202 and the second elongate member 210 each have a distal end (as defined above) and a proximal end that may extend from a proximal end of the delivery device, so that a clinician will be able to use the elongate members 202 & 210 to manipulate the cutting element 204 and the resisting element 212. The elongate members can be constructed from the same material as the cutting element 204 and resisting element 212 or they can be constructed from other suitable biocompatible material that will allow a clinician sufficient control over the elements disposed on the distal end of the elongate members. In at least one embodiment of the apparatus, the elongate elements are flexible.
The cutting element 204 is disposed on the distal end of the first elongate member 202. The cutting element can be made from a biocompatible material, which may have shape memory properties. Examples of suitable materials include, but are not limited to, nitinol, stainless steel, a cobalt-based alloy, and MP35N®. In the embodiment depicted, the cutting element has a delivery configuration (as seen in
As can be further seen in
The resisting element 212 is disposed on the distal end of the second elongate member 210. The resisting element can be made from a biocompatible material, which may have shape memory properties. Examples of suitable materials include, but are not limited to, nitinol, stainless steel, a cobalt-based alloy, and MP35N®. In the embodiment depicted, the resisting element has a delivery configuration (as seen in
When the resisting element of the depicted embodiment is delivered to a tissue membrane, it will be deployed on the side of the membrane nearest to the delivery device while the cutting element is deployed on the opposite side of the membrane. The resisting element provides support to the tissue membrane and resistance to the sharpened edge portion on the base of the cutting element so that the cutting element can cut a section of tissue from the membrane. As will be explained below, when a clinician is using the embodiment of the invention depicted in
While the depicted embodiment shows the second elongate member having a channel communicating therethrough and the first elongate member disposed in that channel, in other embodiments of the invention the first elongate member is hollow and the second elongate member is disposed in the first elongate member. Additionally, at least one embodiment of the current invention does not include a resisting element.
In at least one embodiment, the position of the resisting element (supported by the second elongate member) and the cutting element (supported by the first elongate member) relative to the distal end of the device is reversed such that the resisting element pierces the tissue membrane. When the resisting element of this embodiment is in its delivery configuration, the end can be sharpened or beveled so that it forms a pointed end on the distal most end of the second elongate member. The cutting element of this embodiment is disposed on the end of the first elongate member such that the sharpened edge portion is oriented distally. In such an embodiment, the resisting element is inserted through the tissue membrane and the cutting element is deployed on the side of the tissue member nearest the deployment device.
The cutting element of the depicted device is conical in shape, but other embodiments of the cutting element have different shapes. At least one embodiment of the current invention has a parabolic/dome shaped cutting element and another embodiment has a ring shaped cutting element that is attached to the elongate member with a plurality of attachment members. In another embodiment, the cutting element is wire that is shaped such that it can be manipulated to cut a section of tissue from a tissue membrane.
Embodiments of the cutting element and the resisting element may be made from a biocompatible material that has sufficient elastic properties to permit deformation from a deployment configuration into a delivery configuration and subsequent reformation of the members back into the deployment configuration. Other embodiments of the cutting elements and resisting elements can be deformed from a delivery configuration into a deployment configuration and then undergo subsequent reformation of the members back into the delivery or retrieval configuration.
Materials for use in making the various embodiments of the cutting element and resisting element include any biocompatible material. These materials may have shape memory properties. Such materials can include shape memory metals, shape memory alloys, and plastics having shape memory properties. Suitable materials also have properties that will allow a cutting edge to be sharp enough to cut through a tissue membrane. The cutting elements and resisting elements of the current invention can be attached to the elongate members using any suitable technique that is selected based on the materials used for the various components. Examples of suitable techniques include welding and soldering. Examples of suitable materials include, but are not limited to, nitinol, stainless steel, a cobalt-based alloy, and MP35N®.
In at least one embodiment of the cutting devices disclosed herein, the cutting element and the resisting element are formed in the deployment configuration. The formed members can be heat set to provide the shape memory so that the members can be placed in a delivery configuration, but will re-form into the deployment configuration after delivery to a tissue membrane. In other embodiments having one of a cutting element or a resisting element, that member is formed in the deployment configuration and can then be heat set so that it will re-form to the deployment configuration from the delivery configuration.
Referring now to
Referring to
Once the ventricle floor is secured to the distal end of the delivery device, the cutting element 204 is deployed from the device and advanced through the ventricle floor. A clinician may advance the cutting element by pushing on the first elongate member 202. The vacuum source may then be deactivated or it can remain active through the remainder of the procedure. In various embodiments of a method for using an apparatus as disclosed herein, the vacuum source may be alternately activated and deactivated at various steps depending on the step being performed.
Referring now to
Referring to
Referring to
Once the tissue section has been removed, a clinician can evaluate the flow of CSF through the opening and place a flow meter in the body to monitor the flow if desired. A membrane eyelet can also be placed in the opening to further insure that the opening remains open.
In one embodiment of the apparatus of the current invention, the cutting device (cutting and resisting elements) is withdrawn completely into the delivery device after a section of tissue has been removed from the floor of the ventricle. In another embodiment, the vacuum source may be activated to assist in securing tissue that is removed from the ventricle floor so that it can be withdrawn from a patient's body. In another embodiment of the invention, the tissue section that is removed from a tissue membrane is not withdrawn from a patient's body.
The size of the opening in the floor of the third ventricle will vary based on the age of the patient, the preference of the clinician, and other factors. Preferred embodiments of the devices disclosed herein have cutting elements for creating openings that range in size from 1 mm to 15 mm in diameter. One preferred embodiment of the invention has a cutting element for creating an opening smaller than 1 mm and at least one other embodiment has a cutting element for creating an opening larger than 15 mm. Embodiments of the devices disclosed herein can have cutting elements and resisting elements that are larger in diameter than a delivery device after they are deployed from the delivery device. In at least one embodiment, the diameter of the opening created in the ventricle floor will be larger than the diameter of the delivery device.
As described above, the resisting element is made from a biocompatible material having shape memory properties. The resisting element has a delivery configuration in which the element is collapsed such that it can be easily delivered through the delivery lumen 323 to a location in a body where the resisting device will be used. When the resisting element is in the delivery configuration, the folded element can be sharpened or beveled so that it forms a point on the distal most end of the second elongate member, that can easily penetrate the floor of a third ventricle. The resisting element also has a deployment configuration in which the element assumes a generally planar configuration that is larger in diameter than the diameter of the sharpened edge portion of the cutting element. Another preferred embodiment has a resisting element with a surface that is smaller than the diameter of the base of the cutting element, while yet another embodiment has a resisting element that is the same size as the diameter of the base of the cutting element.
The first elongate member can also serve as the delivery device for the apparatus shown in
To use the embodiment of apparatus disclosed in
An exterior vacuum source can then be activated to secure the ventricle floor 108 snugly against the distal most end of the first elongate member 302. The resisting element 312 is then deployed from the first elongate member such that it is on the opposite side of the floor from the sharpened edge portion of the first elongate member.
The sharpened edge portion (308) of the first elongate member and the resisting element (312) are then manipulated so that they are directly against the floor of the ventricle on opposite sides of the floor. A clinician can then create an opening in the ventricle floor by manipulating the first elongate member to push the cutting element toward the resisting element while simultaneously manipulating the second elongate member so that the resisting element is urged toward the cutting element or at least moving one of the elements while the other is held in one location. The resulting section of tissue that is removed from the floor of the ventricle is secured inside the cutting element. The cutting element and the resisting element are then withdrawn to the distal end of the delivery device, which can then be withdrawn from the patient's body. In at least one embodiment of the invention, a vacuum source is activated to assist in securing tissue that is cut from the ventricle floor so that it can be withdrawn from a patient's body. In another embodiment, tissue that is removed from a tissue membrane is not removed from a patient's body.
Once the tissue section has been removed, a clinician can evaluate the flow of CSF through the opening and place a flow meter in the body to monitor the flow if desired. The clinician can also use a pressure sensor to monitor the pressure gradient of the CSF across the opening. A membrane eyelet can also be placed in the opening to further insure that the opening remains open.
The size of the opening in the floor of the third ventricle will vary based on the age of the patient, the preference of the clinician, and other factors. Embodiments of the apparatus described herein have cutting elements for creating openings in the range of sizes from 1 mm to 15 mm in diameter. One preferred embodiment of the invention has a cutting element for creating an opening smaller than 1 mm and at least one other embodiment has a cutting element for creating an opening larger than 15 mm. In at least one embodiment, the diameter of the opening created in the ventricle floor will be larger than the diameter of the delivery device.
One embodiment of an apparatus of the current invention has a cutting element similar to the cutting element shown in
Referring to
The apparatus of the current invention can also be delivered to a location adjacent to the floor of the third ventricle of a brain via a catheter inserted into the subarachnoid space. To accomplish such a delivery, the clinician must first determine that subarachnoid access (for example by cervical, thoracic, or lumbar puncture) could be performed without risk of cerebral herniation. The clinician would then perform, for example, a lumbar puncture with an introducer and attach a Touhy Borst valve. A catheter would then be inserted through the valve and introducer. The catheter would be navigated superiorly within the spinal subarachnoid space to a location adjacent the floor of the third ventricle. The procedure described herein would then be performed from the subarachnoid space side of the third ventricle floor.
This disclosure provides exemplary embodiments of an apparatus that can be used for creating an opening in a tissue membrane and methods of using the apparatus to create an opening in the floor of a third ventricle. The scope of the present invention is not limited by these exemplary embodiments. Numerous variations, whether explicitly provided for by the specification or implied by the specification or not, such as variations in structure, dimension, type of material and manufacturing process may be implemented by one of skill in the art in view of this disclosure.
