Patent Publication Number: US-2021169519-A1

Title: Trocar device and method

Description:
Claim of Priority 
     This application is a continuation of and claims the benefit of priority under 35 U.S.C. §  120  to U.S. patent application Ser. No. 16/092,719, filed on Oct. 10, 2018, which is a U.S. National Stage Filing under 35 U.S.C. 371 from International Application No. PCT/US2017/180739 A1, filed on Apr. 12, 2017, and published as WO 2017/180739 A1 on Oct. 19, 2017, which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 62/321,571, filed on Apr. 12, 2016, each of which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     This invention relates to devices and methods for insertion of a cannula. 
     BACKGROUND 
     A number of ophthalmological procedures require insertion of a cannula into an eye. Use of a cannula allows insertion and removal of instruments through a single opening, without making additional incisions. Existing technologies for insertion of a cannula use a blade to make an incision, however the blade is often smaller than an inner diameter of the cannula being placed. This can lead to a less precise fit between the incision and the cannula than is desired. Improved devices and procedures are desired to place cannulas into an eye. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A-1C  shows a trocar device according to the prior art. 
         FIG. 2  shows a trocar device according to an embodiment of the invention. 
         FIG. 3A-3B  shows a trocar device blade according to an embodiment of the invention. 
         FIG. 4A-4C  shows a trocar device blade according to an embodiment of the invention. 
         FIG. 5A-5C  shows a trocar device blade according to an embodiment of the invention. 
         FIG. 6A-6B  shows a trocar device blade according to an embodiment of the invention. 
         FIG. 7  shows an example method of inserting a trocar according to an embodiment of the invention. 
         FIG. 8  shows another example method of inserting a trocar according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, or logical changes, etc. may be made without departing from the scope of the present invention. 
       FIG. 1A  shows an example of a cannula  100 . The cannula includes a tube  102  and a cap  104 .  FIG. 1B  shows the cannula  100  when used with a trocar placement tool  110 . The obturator may be used to place the cannula  100  into an eye or other cavity for use in a surgical procedure. The trocar placement tool  110  includes an obturator  112  and a handle  116 . In the example shown, the obturator  112  includes a tip  114 . In the example shown, the tip  114  includes a blade that is used to make an incision to place the cannula  100 .  FIG. 1C  shows an example with the cannula  100  inserted into an eye  120 . The tube portion  102  of the cannula  100  is placed within the eye  120 , while the cap portion  104  remains outside the eye  120  and butts up against an outer surface of the eye  120 . 
       FIG. 2  shows another example of a trocar placement tool  200 . In the example of  FIG. 2 , the trocar placement tool  200  includes a handle  202 , and a gripper  204  that may be used to hold a cannula  220 . Although a single gripper  204  is shown, two or more grippers may also be included. In the example shown, the cannula  220  is similar in size and shape to the example cannula  100  shown in  FIGS. 1A-1C . The cannula  220  is shown with a tube portion  222  and a cap portion  224 . 
     An obturator  210  is shown in  FIG. 2  with a portion  214  that has an outer diameter sized to fit within an inner diameter of the cannula  220 . The obturator  210  of  FIG. 2  further shows a blade  212  at a tip of the obturator  210 . The blade  212  is shown with a width that is wider than the inner diameter of the tube portion  222 . In the example shown, the blade  212  further includes a width that is wider than an outer diameter of the tube portion  222  of the cannula  220 . In one example, the blade  212  is a flexible blade as described in examples below. 
       FIG. 3A  shows one example of a trocar assembly  300  according to an embodiment of the invention. The trocar assembly  300  is shown in a first state that may be used for insertion of a cannula. The trocar assembly  300  includes a shaft portion  302  and a blade portion  304  of an obturator. The blade portion  304  is shown having a first width  306  in an non-deformed state.  FIG. 3A  further shows a tube portion  310  of a cannula located around the shaft portion  302 . In the first state, as illustrated in  FIG. 3A , the first width  306  of the blade  304  is wider than an inner diameter  312  of the tube portion  310 . In one example in the first state, as illustrated in  FIG. 3A , the first width  306  of the blade  304  is also wider than an outer diameter  313  of the tube portion  310 . In one example (not shown) in the first state the first width  306  of the blade  304  may be equal to an outer diameter  313  of the tube portion  310 . 
     In the example shown, the blade  304  includes a cut out  308  that enhances an ability for the blade  304  to deform in a controlled manner.  FIG. 3B  shows the trocar assembly  300  in a second state during removal of the obturator. The blade  304  is in a deformed state where the blade  304  now exhibits a second width  307 . As illustrated in  FIG. 3B , the second width is smaller or equal to the inner diameter  312  of the tube portion  310 . Although any of a number of geometries of cut outs  308  may be used, in the example shown in  FIG. 3B , the cut out  308  deforms at a location  309  to allow a wide portion of the blade  304  to deform to within the second width  307 . 
     In one example, the cut out  308  facilitates deformation of the blade portion  304  from the first width  306  to the second width  307 . Other examples may include a flexible blade portion  304  that does not utilize cut outs to enhance deformation, but otherwise utilizes thin blade material to permit deformation. In the example shown in  FIG. 3B , the deformation of the blade  304  is axial deformation. Other types of deformation may be used in other embodiments of the invention, as discussed below and shown in additional figures. 
       FIG. 4A  shows another example of a trocar assembly  400  according to an embodiment of the invention. The trocar assembly  400  is shown in a first state that may be used for insertion of a cannula. The trocar assembly  400  includes a shaft portion  402  and a blade portion  404  of an obturator. The blade portion  404  is shown having a first width  406  in an non-deformed state.  FIG. 4A  further shows a tube portion  410  of a cannula located around the shaft portion  402 . In the first state, as illustrated in  FIG. 4A , the first width  406  of the blade  404  is wider than an inner diameter  412  of the tube portion  410 . In one example in the first state, as illustrated in  FIG. 4A , the first width  406  of the blade  304  is also wider than an outer diameter  413  of the tube portion  410 . In one example (not shown) in the first state the first width  406  of the blade  404  may be equal to an outer diameter  413  of the tube portion  410 . 
     In the example shown, the blade  404  includes a multiple cut outs  408  that enhance an ability for the blade  404  to deform in a controlled manner.  FIG. 4B  shows the trocar assembly  400  in a second state during removal of the obturator. The blade  404  is in a deformed state where the blade  404  now exhibits a second width  407 . As illustrated in  FIG. 4B , the second width is smaller or equal to the inner diameter  412  of the tube portion  410 . In contrast to the example of  FIGS. 3A-3B , the cut outs  408  of blade  404  facilitate flexion upwards (or downwards) out of a plane of the blade  304 .  FIG. 4C  shows an end view of the blade  404  with portions  405  is a deformed state, flexed out of a plane of blade  404 . 
     Similar to the example of  FIGS. 3A-3B , examples of the invention are not limited to configurations that include cut outs  408 . Other examples may include a flexible blade portion  404  that does not utilize cut outs to enhance deformation, but otherwise utilizes thin blade material to permit deformation. 
       FIG. 5A  shows one example of a trocar assembly  500  with a flexible blade that does not include a cutout according to an embodiment of the invention. The trocar assembly  500  is shown in a first state that may be used for insertion of a cannula. The trocar assembly  500  includes a shaft portion  502  and a blade portion  504  of an obturator. The blade portion  504  is shown having a first width  506  in an non-deformed state. End view illustration  508  also shows the non-deformed state, 
       FIG. 5A  further shows a tube portion  510  of a cannula located around the shaft portion  502 . In the first state, as illustrated in  FIG. 5A , the first width  506  of the blade  504  is wider than an inner diameter  512  of the tube portion  510 . In one example in the first state, as illustrated in  FIG. 5A , the first width  506  of the blade  504  is also wider than an outer diameter  513  of the tube portion  510 . In one example (riot shown) the first state the first width  506  of the blade  504  may be equal to an outer diameter  513  of the tube portion  510 . 
     End view illustration  509  shows the blade  504  in a second state during removal of the obturator. The blade  504  is in a deformed state where the blade  504  now exhibits a second width  507 . The second width  507  is smaller or equal to the inner diameter  512  of the tube portion  510 . The example of  FIGS. 5A-5C  shows another example of flexion out of a plane of the blade  304 . End view  509  illustrates a distributed flexing gradient across substantially all of the blade  504 . The blade  504  is shown with a substantially smooth curve. 
       FIG. 5B  shows an end view of the blade  504  that further illustrates the tube portion  510 . In  FIG. 5B , the blade  504  is in an non-deformed state, and the end view  508  is wider than an inner diameter  512  of the tube portion  510 . In this example the blade  504  is also wider that the outer diameter  513  of the tube portion  510 .  FIG. 5C  shows an end view of the blade  504  in a deformed state, flexed out of a plane of blade  504 . and the end view  509  is thinner than the inner diameter  512  of the tube portion  510 . 
     In operation, a surgeon may insert an obturator with a blade portion similar to blade portions  304 ,  404 , and  504  and shaft portions similar to shaft portions  310 ,  410 , and  510  into tissue such as eye tissue. In one state, as described above, the blade portions  304 ,  404 , and  504  are wider than or equal to outer diameters of the tube portions  310 ,  410 , and  510 . This facilitates an incision in tissue such as eve tissue that is wide enough to allow the tube portions  310 ,  410 , and  510  to pass through. Because the blade portions  304 ,  404 , and  504  are flexible, and are adapted to deform, they may be withdrawn through the inner diameter of the tube portions  310 ,  410 , and  510 . 
       FIGS. 6A and 6B  show a trocar assembly  600  according to another example of the invention. The assembly  600  includes a shaft portion  602  and a blade portion  604  of an obturator. In  FIG. 6A , the blade portion  604  is shown having a first width  607  in an non-deformed state. In  FIGS. 6A and 6B , the non-deformed state provides the first width  607  that is smaller or equal to an inner diameter  612  of a tube portion  610 . 
     In the example of  FIG. 6A , the blade portion  604  includes an internal space  608  that is normally compressed at location  609 . The compression at location  609  allows the width  607  of the blade portion  604  to be smaller or equal to the inner diameter  612  of the tube portion  610 . Although one possible configuration of a compression  609  is shown, other locations and/or configurations of compression features or constrictions are within the scope of the invention. 
     As in other examples presented above, the blade portion  604  is a flexible blade portion.  FIG. 6A  further shows a dilator  650  adapted to fit within the internal space  608  within the blade portion  604 . As a tip  652  of the. dilator  650  enters the internal space  608  of the blade portion  604 , the internal space  608  is expanded to a deformed state shown in  FIG. 6B . In  FIG. 6B , with the dilator  650  inserted within the internal space  608 , the blade portion  604  is deformed or otherwise expanded to a second width  606 . As illustrated in  FIG. 6B , the second width  606  of the blade  604  is wider than an inner diameter  612  of the tube portion  610 . In one example, as illustrated in  FIG. 6B , the second width  606  of the blade  604  is also wider than an outer diameter  613  of the tube portion  610 . In one example (not shown) the second width  606  of the. blade  604  may be equal to an outer diameter  613  of the tube portion  610 . 
     In operation, a surgeon may insert the obturator with the blade portion  604  and the shaft portion  620  inside the tube portion. Because the blade portion is in the non-deformed state shown in  FIG. 6A . the obturator will slide through the tube portion  610 . Then the dilator  650  may be inserted into the internal space  608  of the blade portion  604 . This will deform the blade portion  604  to the second width  606  as shown in  FIG. 6B . Now the blade portion  604  is wider than or equal to an outer diameter  613  of the tube portion  610 . This facilitates an incision in tissue such as eye tissue that is wide enough to allow the tube portion  610  to pass through. 
     The surgeon may then remove the dilator  650  from within the blade  604  of the obturator. The blade  604  will once again return to the width  607  that is smaller or equal to the inner diameter  612  of the tube portion  610 . The obturator and the blade  604  will thus be easily removed through the tube portion. 
     This procedure and the devices described allow a procedure to make a wide incision as a result of the temporary increased width  606 . This procedure and the devices described also allow the obturator to be withdrawn from within the tube portion  610  with a decreased width  607  after making the incision. 
       FIG. 7  shows an example method according to one example. In operation  702 , a trocar assembly is pushed into a tissue, the trocar assembly including a flexible blade having a width that is larger than an inner diameter of a cannula. Ire operation  704 , an incision is formed in the tissue wider than the inner diameter of the cannula using the flexible blade and guiding the cannula into the tissue through the incision. In operation  706 , the obturator and the blade are withdrawn, leaving the cannula in place. In operation  708 , the flexible blade is deformed while withdrawing the obturator and the blade such that the deformed blade has a width that is equal to or smaller than the inner diameter of the cannula. 
       FIG. 8  shows another method according to one example. In operation  802 , a trocar assembly is pushed into a tissue, the trocar assembly including a flexible blade at a tip of the obturator. In operation  804 , an incision is formed in the tissue wider than the inner diameter of the cannula using the flexible blade and guiding the cannula into the tissue through the incision. In operation  706 , a dilator is withdrawn, causing the flexible blade to have a second width that is equal to or less than the inner diameter of the cannula. In operation  708 , the obturator and the blade are withdrawn, leaving the cannula in place. 
     To better illustrate the method and apparatuses disclosed herein, a non-limiting list of embodiments is provided here: 
     Example 1 includes a trocar assembly. The assembly includes a cannula, an obturator within the cannula, and a flexible blade at a tip of the obturator, the flexible blade having a width that is larger than an inner diameter of the cannula, wherein the flexible blade is adapted to deform sufficiently to allow the obturator to be withdrawn through the inner diameter of the cannula. 
     Example 2 includes the trocar assembly of example 1, wherein the flexible blade is substantially flat. 
     Example 3 includes the trocar assembly of any one of examples 1-2, wherein the width is larger than the outer diameter of the cannula. 
     Example 4 includes the trocar assembly of any one of examples 1-3, wherein the flexible blade is adapted to curl sufficiently to allow the obturator to he withdrawn through the inner diameter of the cannula. 
     Example 5 includes the trocar assembly of any one of examples 1-4, wherein the flexible blade is adapted to compress axially to allow the obturator to be withdrawn through the inner diameter of the cannula. 
     Example 6 includes the trocar assembly of any one of examples 1-5, wherein the flexible blade includes one or more cut outs within the blade to enhance flexing. 
     Example 7 includes the trocar assembly of any one of examples 1-6, wherein the flexible blade includes a central cut out within the blade to enhance flexing. 
     Example 8 includes the trocar assembly of any one of examples 1-7, wherein the flexible blade includes a pair of side cut outs within the blade to enhance flexing. 
     Example 9 includes the trocar assembly of any one of examples 1-4, wherein the flexible blade includes a steel blade. 
     Example 10 includes a trocar assembly. The assembly includes a cannula, an obturator within the cannula, a flexible blade at a tip of the obturator, the flexible blade haying an internal space within the blade, and a dilator adapted to fit within the internal space within the blade, wherein a first width of the blade is equal to or wider than an inner diameter of the cannula when the dilator is inserted within the internal space, and wherein a second width of the blade is equal to or smaller than the inner diameter of the cannula when the dilator is removed from the internal space. 
     Example 11 includes the trocar assembly of example 10, wherein the obturator and the blade are integrally formed. 
     Example 12 includes the trocar assembly of any one of examples 10-11, wherein the blade is substantially flat. 
     Example 13 includes the trocar assembly of any One of examples 10-12, wherein the flexible blade includes a steel blade. 
     Example 14 includes a method of inserting a trocar. The method includes pushing a trocar assembly into a tissue, the trocar assembly including a cannula, an obturator within the cannula, and a flexible blade at a tip of the obturator, the flexible blade having a width that is larger than an inner diameter of the cannula. The method also includes forming an incision in the tissue wider than the inner diameter of the cannula using the flexible blade and guiding the cannula into the tissue through the incision, withdrawing the obturator and the blade, leaving the cannula in place, and deforming the flexible blade while withdrawing the obturator and the blade such that the deformed blade has a width that is equal to or smaller than the inner diameter of the cannula. 
     Example 15 includes the method of example 14, wherein deforming the flexible blade includes curling the flexible blade. 
     Example 16 includes the method of any one of examples 14-15, wherein deforming the flexible blade includes axially compressing at least a portion of the blade. 
     Example 17 includes a method of inserting a trocar. The method includes pushing a trocar assembly into a tissue, the trocar assembly including a cannula, an obturator within the cannula, a flexible blade at a tip of the obturator, and a dilator within the flexible blade causing the flexible blade to have a first width that is larger than an inner diameter of the cannula. The method also includes forming an incision in the tissue wider than the inner diameter of the cannula using the flexible blade and guiding the cannula into the tissue through the incision, withdrawing the dilator, causing the flexible blade to have a second width that is equal to or less than the inner diameter of the cannula, and withdrawing the obturator and the blade, leaving the cannula in place. 
     Example 18 includes the method of example 17, wherein withdrawing the dilator includes withdrawing the dilator from an internal space within obturator and the blade, wherein the internal space tapers to a more narrow space within the blade. 
     These and other examples and features of the present infusion devices, and related methods will be set forth in part in the above detailed description. This overview is intended to provide non-limiting examples of the present subject matter—it is not intended to provide an exclusive or exhaustive explanation. 
     The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples((or one or more aspects thereof) shown or described herein. 
     In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the teen “or” is used to refer to a nonexclusive or, such that. “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may he grouped together to streamline the. disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment, Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.