Patent Application
20190388144
The invention relates generally to medical instruments used for endoscopic mucosal resection and submucosal dissection.
One of the most common forms of cancer is colon cancer. Most cases begin with formation of small, noncancerous clumps of cells called lesions or polyps in the large intestine. The polyps may produce few, if any, symptoms, but the polyps can become colon cancer over time. Physicians recommend screening and polyp removal before the polyps turn into cancer.
Colonoscopy may be used for diagnosis and removal of the polyps. The procedure uses a long, flexible, slender tube attached with a camera to view the colon and rectum. If suspicious areas are found, the physician may pass surgical tools through the tube. The surgical tools may be used to take tissue samples and remove polyps.
When the entire polyp is removed, there is a lower risk of reoccurrence of polyps in the removal area. Removing each polyp as a whole, or “en bloc”, allows for further study of the polyp and is useful for diagnostic and treatment purposes. In the removal procedure, a surgical tool would be used to cut into the mucosal layer and the submucosal layer to remove the polyp. Complications arise when cutting beyond the submucosal layer. For example, the physician may cut into the muscular layer and may perforate the colon, there may be excess bleeding or infection, and there may be increased recovery time.
Removal of the entire lesion or polyp, while keeping the lesion or polyp intact, is difficult when using traditional, rigid surgical tools that require extensive training before use and have a complicated method of use. The present invention provides a medical instrument with a flexible, rotatable knife that uses an electric current to cut into the tissue layers and a simple removal process for removal of lesions or polyps. The flexible knife has a spear-shaped insulated tip that guides the flexible knife and prevents the knife from cutting into the muscular layer. The present invention may be used for en bloc resection or dissection of lesions or polyps and provides an easy, effective procedure.
The flexible knife may extend from the flexible tubing or sheath to expose different lengths of the knife. For example, the flexible knife may extend a further distance from a distal end of the sheath and thus extend a further distance from the distal end of the endoscope than traditional knives. For example, a flexible knife according to the present invention may extend about 2 cm from the distal end of the sheath, which is a length greater than the 1-2 mm length offered by traditional knives. This allows the sheath to avoid contacting the lesion or polyp while the knife is used to cut the lesion or polyp, thereby maintaining the integrity of the lesion or polyp. This also allows for better view of the procedure, as a camera in an endoscope through which the instrument is received may not be impeded by blood flow resulting from cutting the lesion or polyp.
Furthermore, a procedure using a flexible knife of the present invention has a shorter duration than a similar procedure using a traditional knife. When using a traditional knife, the tip of the knife and the end of the endoscope are close in distance to the polyp or lesion to be removed. While cutting the polyp or lesion, the process must be stopped in order to cauterize the wound and halt excess bleeding which impedes the view of the endoscope camera. In a process according to the present invention, the endoscope camera is located a further distance away from the polyp or lesion to be removed. In addition, the sweeping motion of cutting the polyp or lesion with the electric current produces less excess bleeding and thus does not require stopping of the process to cauterize wound as frequently. Because there is less stopping to cauterize, removal of a polyp or lesion using a procedure according to the present invention has a shorter duration than similar processes using traditional knives. Additionally, the flexible knife of the medical instrument is easier to use and has less training time than the traditional short, rigid-tipped surgical tools.
Typically, traditional knives have tips that are short and hard, have a transparent hood, and have less rotation and length adjustment. The traditional knives are used to carve out the lesion or polyp and are restricted by a short distance and limited vision when cutting. The length of the knife is not adjustable for cutting at different depths. While cutting, the knife has to be very close to the lesion or polyp, with the nose of the knife pointed downward and then rising to carve out the lesion or polyp. The integrity of the lesion or polyp may be damaged if the end of the knife and the cover of the knife directly touch the lesion or polyp. The knife does not exhibit flexibility when cutting. The angle of approach may not be ideal with the traditional knife, as the end of the knife is rigid and cannot bend or contour over the surface of the gastrointestinal (GI) tract. This may lead to cutting through the tissue layers and into the muscular layer.
The present invention may be used for endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD). EMR and ESD are two procedures conducted to remove lesions or polyps in the GI tract. The EMR procedure takes less time and is a less complicated procedure than the ESD procedure. However, EMR does not achieve en bloc removal of lesions or polyps, does not allow for precise histological stage, and there is a high risk of reoccurrence of polyps or lesions in the removal area. The medical instrument of the present invention may be used for EMR and ESD. The sheath of the medical instrument may further be configured to operate within a working channel in an endoscope.
In an aspect of the invention, a medical instrument comprises a proximal handle comprising an electrical connection plug, a slidable handle portion, and a rotatable handle portion. A sheath extends from the proximal handle, the sheath comprising a lumen and a distal end away from the proximal handle. A cutting assembly extends through the sheath, the cutting assembly comprising a wire and a working end, the cutting assembly and sheath moveable relative to each other to cover and reveal the working end such that the working end has a retracted position and a working position. The working end comprises a flexible knife comprising a distal end, a proximal end, and an insulated portion. An insulated spear-shaped tip is provided at the distal end of the flexible knife, and the insulated spear-shaped tip preventing cutting of a layer other than a mucosal layer or a submucosal layer. The insulated spear-shaped tip further acts as a pivot point when the distal end of the flexible knife is pushed down, which allows the cutting edge to be rotated about that pivot point.
The slidable handle portion can be manipulated by a user to move the working end forward and backward between the retracted position and working position. The rotatable handle portion can be manipulated by the user to rotate the cutting assembly. The rotatable handle may also be manipulated to stay in a locked position so that no rotation occurs. Alternatively, the sheath can be operable by the proximal handle to cover and reveal the working end of the cutting assembly from the distal end of the sheath.
The flexible knife of the invention uses electrical current to cut tissue. In particular, part of the flexible knife may be exposed in order to use the electrical current for cutting. The part of the flexible knife that is not used for cutting may be insulated. The electrical connection plug in the proximal handle is configured to connect to an electric power source to supply the electrical current. The wire extending through the sheath may be insulated. The proximal end of the flexible knife connects to the wire. In an embodiment, the flexible knife comprises a wire loop. The insulated portion may comprise a portion of the flexible knife from the insulated spear-shaped tip to the proximal end of the flexible knife.
Looking at the knife when extended from the sheath, one side of the knife may be exposed and used for electrical cutting action. The remaining portion of the knife may be insulated from the spear-shaped tip on the distal end of the knife to the sheath. The insulated part of the knife clings to the tissue while the knife is electrically cutting, helping to guide and contour the knife over the terrain and prevent cutting into other layers.
The medical instrument of the present invention may be used to electrically cut tissue, such as a polyp or lesion. Dissection or resection of the lesion or polyp involves cutting the lesion or polyp out of the mucosal and/or submucosal layer. However, cutting too deep may result in cutting the muscular layer and perforating the intestinal wall. The insulated spear-shaped tip of the present invention guides the flexible knife into the lesion or polyp and prevents cutting of a layer other than a mucosal layer or a submucosal layer.
Further, the present invention uses a sweeping cutting motion instead of cutting away a polyp or lesion in a carving manner, such as used by traditional knives. For example, electrically cutting is in a sweeping motion may entail cutting from one side of the lesion or polyp to the opposite side of the lesion or polyp.
Other aspects and advantages of the invention will be apparent upon consideration of the following detailed description thereof.
The present invention provides a medical instrument having a flexible knife that is rotatable, extends from a sheath, uses electric current to cut, and is operable by a proximal handle. A distal end of the flexible knife has an insulated spear-shaped tip. The tip helps to guide the flexible knife into a lesion or polyp, contour to terrain, and prevent the flexible knife from cutting into layers that are not the mucosal layer or submucosal layer, e.g. the muscular layer. The flexible knife may comprise a wire loop. Looking at the knife when extended from the sheath, one side of the knife may be exposed and used for electrical cutting action. The remaining portion of the knife may be insulated from the spear shaped tip on the distal end of the knife to the sheath. The insulated part of the knife clings to the tissue while the knife is electrically cutting.
The present invention has greater flexibility and rotation capabilities than a knife having a short, rigid tip. For instance, the flexible knife can extend from the sheath and embody different lengths. The knife may be fully retracted in the sheath, may extend partially out of the sheath, or may extend fully out of the sheath. The knife may comprise a flexible, electrically conductive wire. The wire may be a braided wire.
Traditional knives require use of transparent hoods or caps during EMR or ESD procedures. The cap is used to maintain visualization when using a traditional knife during an EMR or ESD procedure, as the cap keeps the resected flap of mucosa off of the endoscope lens. The present invention does not require a transparent hood. The adjustable knife length of the present invention allows extension of the knife from the sheath and provides options for length of the knife during use. As such, the dissection or resection may be carried out at a distance from the endoscope.
Traditional knives also have knife tips that are difficult to insert into the submucosa layer. Insertion difficulty of the knife tip on a traditional knife may lead to using excess force and cutting deeper than the submucosa layer. In the present invention, the insulated spear-shaped tip experiences less difficulty plunging into the submucosa and prevents the knife from cutting into the muscular layer.
Furthermore, when using traditional knives, any cutting direction adjustment is carried out by endoscopy. The present invention allows for adjustment of the cutting direction by using endoscopy or by adjusting the cutting assembly by manipulation of the proximal handle. The cutting assembly is flexible and rotatable. Further, the present invention has options for the length of extension or protrusion of the cutting assembly from the sheath, thereby allowing for use of different lengths of the exposed knife for electrical cutting.
One aspect of the medical instrument of the present invention is that the instrument 1 may be received within an endoscope 5, such as shown in
A body 41 of the proximal handle 30 may further comprise graduated markings or gradient markers 47. The gradient markers 47 may correspond to a length of the wire 81 for extending or retracting the working end 74 of the cutting assembly 70 from the sheath 50.
Optionally, a setting clip 45 may be used to specify a distance for moving the slidable handle portion 39 and the second slidable handle portion 33. The setting clip 45 may be arranged on the body 41 of the proximal handle 30 at a position marked by the gradient markers 47. The setting clip 45 may be arranged on the body 41 of the proximal handle 30 at a position between the slidable handle portion 39 and the second slidable handle portion 33.
The procedural steps for EMR and ESD are similar. The lesion or polyp is marked, fluid is injected into the submucosa to elevate the lesion or polyp, the mucosa surrounding the lesion or polyp is cut, and the submucosa beneath the lesion or polyp is dissected. Marking may be done using cautery or small electrosurgical burns (e.g. argon plasma coagulator) to mark the periphery of the lesion or polyp. A saline solution that includes a dye (e.g. indigo carmine, methylene blue) is typically used for injection.
The core step of EMR or ESD is resection or dissection of the lesion or polyp to produce a sample to be used for diagnosis and evaluation. En bloc resection is more desirable than piecemeal resection, as it allows for more accurate assessment and appropriateness of the therapy. As such, ESD is preferably performed, as ESD provides a sample of the lesion or polyp en bloc. The collected sample may then undergo strict and precise pathological diagnosis and evaluation. Complications may arise from the procedure, such as perforation, bleeding, stenosis, etc., which may lead to increased recovery time and long-term follow-up. Steps for the resection or dissection procedure include marking the lesion or polyp, injection, incision, dissection, sample collection of the lesion or polyp, and wound management.
The resection or dissection steps are shown in
Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein will become apparent to those skilled in the art from the full contents of this document. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.
