Patent Publication Number: US-2020276010-A1

Title: Graft tissue injector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims priority to U.S. Provisional Patent Application No. 62/812,001, filed Feb. 28, 2019, entitled GRAFT TISSUE INJECTOR, the entirety of which is incorporated herein by reference. 
    
    
     GOVERNMENT RIGHTS STATEMENT 
     None. 
     TECHNICAL FIELD 
     This disclosure relates generally to a device and method for aspirating graft tissue and delivering the graft tissue to a target delivery site, such as within an anterior chamber of an eye. 
     BACKGROUND 
     Corneal transplants or grafts are the most common and successful transplantation procedures in medicine. In fact, more than 280,000 donor corneas are recovered every year and at least 180,000 corneal transplants are performed annually worldwide. According to a global survey that was conducted between 2012 and 2013, around 40% of the corneas were recovered in the United States. 
     The cornea is the clear, protective outer layer of the eye, and consists primarily of three layers, namely, the corneal epithelium (outer layer), the corneal stroma, and the corneal endothelium (inner layer). Each layer has different characteristics. For example, the corneal epithelium is a thin multicellular epithelial tissue layer of fast-growing and easily regenerated cells. The corneal stroma is a thick transparent middle layer that includes regularly arranged collagen fibers and keratocytes, which are the cells that help maintain the structure of the corneal stroma. The corneal stroma consists of approximately 200 layers of mainly type I and type V collagen fibers. Up to 90% of the corneal thickness is composed of stroma. 
     Finally, the corneal endothelium is a monolayer of mitochondria-rich cells. These cells are responsible for regulating fluid and solute transport between the aqueous humor and corneal stroma. Unlike the corneal epithelium, endothelial cells do not regenerate. Instead, they stretch to compensate for dead cells, which reduces the overall cell density of the endothelium, which affects fluid regulation. If endothelial cells can no longer maintain a proper fluid balance, stromal swelling due to excess fluids and subsequent loss of transparency will occur, which may cause corneal edema. 
     Fuchs&#39; endothelial dystrophy and pseudophakic bullous keratopathy (PBK) are two of the most frequent indications for corneal transplantation. Until a few years ago, full thickness corneal transplantation was the only available treatment for endothelial layer replacement. However, although this procedure is able to restore corneal endothelial function, it has several drawbacks, such as high post-operative astigmatism, risk of tissue dehiscence and risk of infections and tissue rejection. 
     In the 1960s, a method of endothelial keratoplasty (EK) using an anterior approach via a laser-assisted in situ keratomileusis (LASIK) flap was described, and in 1999, a technique for posterior lamellar keratoplasty was developed. In a procedure called posterior lamellar keratoplasty (PLK), the posterior lamella, Descemet&#39;s membrane, and endothelium was dissected through a 9-mm sclerocorneal incision. A donor button consisting of posterior stroma, Descemet&#39;s membrane, and endothelium was then inserted and held in place by an air bubble while the patient lay supine. 
     In the 1990s, as the PLK procedure was further modified and a procedure called deep lamellar endothelial keratoplasty (DLEK) was developed. DLEK eliminated surface corneal sutures and incisions, leading to faster visual rehabilitation. However, DLEK requires the manual lamellar dissection of the deep corneal stroma from both donor and recipient, which is considered by surgeons to be difficult and laborious. 
     This consequently led to the development of Descemet&#39;s stripping endothelial keratoplasty (DSEK). DSEK has the advantages of being easier for the surgeon to perform and of providing a smoother interface on the recipient side for the visual axis. Preparation of the donor tissue in endothelial keratoplasty has also been made easier with the utilization of an automated microkeratome. The addition of this component to the surgical procedure has been popularized as Descemet&#39;s stripping automated endothelial keratoplasty (DSAEK). 
     Descemet&#39;s membrane endothelial keratoplasty (DMEK) is a partial-thickness cornea transplant procedure that involves a selective transplantation of a monolayer of donor endothelial cells and Descemet&#39;s membrane in the absence of a stromal tissue carrier. While the idea of DMEK was first introduced in 1998, the first successful report of DMEK did not occur until 2006. 
     In the DMEK technique, the donor corneoscleral rim is positioned with the endothelial side up. The scleral spur and Descemet&#39;s membrane are separated for 360 degrees, after which a superficial trephination of approximately 9 mm is made in the posterior stroma. The donor corneoscleral rim is submerged under Optisol or balanced saline solution (BSS) to decrease the surface tension and lower the risk of a potential Descemet&#39;s membrane tear. The endothelium is stripped from the posterior donor stroma with nontoothed forceps, creating a circular sheet of Descemet&#39;s membrane with an endothelial monolayer of cells. Owing to the elastic properties of the Descemet&#39;s membrane, a “Descemet&#39;s roll” forms spontaneously after the circular layer of endothelium/Descemet&#39;s membrane is removed from the donor posterior stroma, with the endothelium on the outside of the roll. The roll of tissue is stained with 0.06% trypan blue. The tissue is next placed in a tissue injector. Next, a scleral or corneal incision is made. With a reverse Sinskey hook, a circular portion of Descemet&#39;s membrane is scored and stripped from the recipient posterior stroma, completing a 9.0-mm diameter “descemetorhexis.” The stripped Descemet&#39;s membrane and endothelium are removed from the eye. Using the injector, the donor tissue roll is inserted into the anterior chamber and the graft is oriented endothelial side down by indirect manipulation of the tissue with air and/or fluid. While maintaining the anterior chamber with fluid and air, the graft is gently spread out over the iris. Then, an air bubble is injected underneath the donor Descemet&#39;s membrane to position the tissue onto the recipient posterior stroma. The anterior chamber is completely filled with air for 30 to 60 minutes followed by an air-liquid exchange to pressurize the eye. 
     Loading of the tissue into the injector and inserting the tissue into the anterior chamber are two of the most important steps in the DMEK procedure. Loading of the tissue requires controlled vacuum to draw the tissue towards the injector. Some injectors require the tissue to be loaded through the injection end, which is narrow and makes the aspiration more difficult and traumatic. For this reason, new injectors allow the tissue to be loaded through the connection part of the injector, which has a larger diameter and makes the aspiration easier and less traumatic for the tissue. However, these types of injectors require extra tubing to aspirate the tissue, as the syringe cannot be adapted to the connection part of the injector. Additionally, aspiration of the tissue requires vacuum, which sometimes is difficult to control and causes the tissue to be aspirated too rapidly or to slowly. This can cause the tissue to hit the walls of the injector, potentially causing endothelial cell loss. 
     On the other hand, insertion of the tissue into the anterior chamber is performed by pressing the plunger of a syringe preloaded with BSS. Unfortunately, pressure cannot be accurately controlled and the tissue is often injected too rapidly into the anterior chamber and hits the anterior chamber angle, which can cause endothelial cell loss. Additionally, to minimize the induced astigmatism caused by the incision and to improve chamber stability, new injectors have a smaller diameter that can go through small incisions of approximately 2.5 mm. However, this smaller injector diameter causes more friction against the tissue and may also cause endothelial cell loss during tissue insertion. 
     SUMMARY 
     Some embodiments advantageously provide a device, system, and method for aspirating graft tissue and delivering the graft tissue to a target delivery site. In one non-limiting example, the device and method may be used to deliver graft tissue to a location within an anterior chamber of an eye when performing Descemet&#39;s membrane endothelial keratoplasty. In one embodiment, an injector comprises: a cylinder; and a plunger at least partially located within the cylinder, the plunger being rotatably advanceable within the cylinder and one of rotatably retractable and linearly retractable within the cylinder. 
     In one aspect of the embodiment, the plunger is rotatably retractable within the cylinder, rotating the plunger in a first direction within the cylinder is configured to controllably aspirate a graft tissue into the injector and rotating the plunger in a second direction opposite the first direction is configured to controllably eject the graft tissue from the injector. In one aspect of the embodiment, the plunger includes: a shaft having a first portion and a second portion opposite the first portion, the second portion having a free end; and a knob coupled to the first portion, an outer surface of at least a portion of the first portion defining threading. In one aspect of the embodiment, the cylinder includes a body having an inner surface, at least a portion of the inner surface defining threading that is complementary to the threading of the first portion of the outer surface of the shaft of the plunger. 
     In one aspect of the embodiment, the plunger is linearly retractable within the cylinder. In one aspect of the embodiment, the cylinder includes an inner surface, at least a portion of the inner surface having an interrupted threading with a threaded portion and a non-threaded portion extending longitudinally through the threaded portion; and the plunger includes a shaft having a follower, the follower being configured to travel within the threaded portion when the plunger is rotatably advanced and being configured to travel within the non-threaded portion when the plunger is linearly retracted. 
     In one aspect of the embodiment, the cylinder includes a body having: a first opening; a second opening opposite the first opening; and a chamber, the chamber being in fluid communication with the first opening and the second opening. In one aspect of the embodiment, the cylinder further includes an end wall at least partially defining the second opening and a connection extension, the connection extension having: a first end meeting the end wall; a second end opposite the first end, the second end defining an opening; and a lumen, the lumen being in fluid communication with the second opening of the body and the second opening of the connection extension. In one aspect of the embodiment, the body has a first longitudinal axis and the connection extension has a second longitudinal axis that is different than the first longitudinal axis, the second longitudinal axis being oriented at an angle from the first longitudinal axis. 
     In one aspect of the embodiment, the angle is less than approximately 90°. 
     In one aspect of the embodiment, the second longitudinal axis is oriented at an angle from the first longitudinal axis, the angle being between approximately 22.5° and approximately 67.5°. 
     In one aspect of the embodiment, the injector further comprises a tissue cartridge including: a first portion defining a first opening and having a first outer diameter, the first opening having a first diameter; a second portion opposite the first portion and defining a second opening, the second portion having a second outer diameter that is less than the first outer diameter of the first portion and the second opening having a second diameter that is less than the first diameter of the first opening; and a chamber, the chamber being in fluid communication with the first opening of the tissue cartridge and the second opening of the tissue cartridge. In one aspect of the embodiment, the connection extension has an outer diameter that is slightly smaller than the first diameter of the first opening of the tissue cartridge, such that the connection extension is removably insertable within the first opening of the tissue cartridge and securable therein by friction fit; and the connection extension has an inner diameter that is slightly larger than the outer diameter of the second portion of the tissue cartridge, such that the second portion of the tissue cartridge is removably insertable within the connection extension and securable therein by friction fit. 
     In one aspect of the embodiment, the tissue cartridge further includes an inner surface and an outer surface, at least a portion of at least one of the inner surface and the outer surface being coated with at least one layer of a nano-ceramic material. 
     In one embodiment, a kit for corneal transplant comprises: an injector including: a cylinder, the cylinder having a bent configuration; and a plunger at least partially insertable into the cylinder, the plunger being rotatably advanceable within the cylinder and at least one of rotatably and linearly retractable within the cylinder; and a container including a tissue cartridge with a graft tissue therein, the tissue cartridge including a first portion with a first opening and a second portion with a second opening opposite the first opening, the tissue cartridge being reversibly couplable to the cylinder of the injector. In one aspect of the embodiment, the container further includes: a reservoir portion; a lid; a latch mechanism configured to couple the reservoir portion and lid; and a chamber defined between the reservoir portion and the lid, the chamber being sized and configured to contain the tissue cartridge. In one aspect of the embodiment, the container further includes: at least one first positioning element coupled to the lid and extending in a first direction; at least one second positioning element coupled to the reservoir portion and extending in a second direction opposite the first direction; and at least one containment element, the at least one first positioning element and the at least one second positioning element being configured to retain the tissue cartridge therebetween and the at least one containment element being configured to at least partially obstructing the first opening of the tissue cartridge when the lid is coupled to the reservoir portion and the tissue cartridge is within the chamber. In one aspect of the embodiment, the cylinder has a connection extension, the cylinder having a first longitudinal axis and the connection extension having a second longitudinal axis that is different than the first longitudinal axis, the second longitudinal axis being oriented relative to the first longitudinal axis by an angle of between approximately 22.5° and approximately 67.5°. 
     In one embodiment, a method of delivering corneal graft tissue to a delivery site comprises: inserting a connection extension of a cylinder of an injector into a first opening of a first portion of a tissue cartridge, the cylinder having a body with a first longitudinal axis, the connection extension extending from the body and having a second longitudinal axis that is different than the first longitudinal axis, an inner surface of the cylinder having a first threading; inserting a second portion of the tissue cartridge having a second opening through an incision and into an anterior chamber of a patient&#39;s eye, the second portion of the tissue cartridge having an outer diameter that is smaller than an outer diameter of the first portion of the tissue cartridge; and rotating a plunger in a first direction within the cylinder to advance a shaft of the plunger within the cylinder to inject the graft tissue into the anterior chamber of the patient&#39;s eye through the second opening of the tissue cartridge, the shaft of the plunger having a second threading that is complementary to and engages the first threading. In one aspect of the embodiment, the method further comprising, before the step of inserting a connection extension of a cylinder of an injector into a first opening of a first portion of a tissue cartridge: inserting the second portion of the tissue cartridge within an opening of the connection extension; positioning the first opening of the tissue cartridge proximate the graft tissue; rotating the plunger in a second direction opposite the first direction within the cylinder to retract the shaft of the plunger within the cylinder to aspirate the graft tissue into the tissue cartridge through the first opening of the tissue cartridge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of embodiments described herein, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  shows an exemplary embodiment of a graft tissue injector having a plunger and a tissue cartridge in accordance with the present disclosure, the plunger being in a first position and the tissue cartridge being in an injection configuration; 
         FIG. 2  shows the graft tissue injector of  FIG. 1 , the plunger being in a second position and the tissue cartridge being in the injection configuration in accordance with the present disclosure; 
         FIG. 3  shows the graft tissue injector of  FIG. 1 , the tissue cartridge being in an aspiration configuration in accordance with the present disclosure; 
         FIG. 4  shows an exemplary embodiment of the plunger for a graft tissue injector, for example, a graft tissue injector of  FIG. 1 , in accordance with the present disclosure; 
         FIG. 5  shows an exemplary embodiment of a cylinder of the graft tissue injector of  FIG. 1  in accordance with the present disclosure; 
         FIG. 6  shows an exemplary embodiment of a tissue cartridge for the graft tissue injector in accordance with the present disclosure; 
         FIG. 7  shows an exemplary embodiment of a graft tissue injector having a plunger and a tissue cartridge in accordance with the present disclosure, the plunger being in a first position and the tissue cartridge being in an aspiration configuration; 
         FIG. 8  shows the graft tissue injector of  FIG. 7 , the plunger being in a second position and the tissue cartridge being in the injection configuration in accordance with the present disclosure; 
         FIG. 9  shows an exemplary embodiment of a plunger for a graft tissue injector, for example, a graft tissue injector of  FIG. 7 , in accordance with the present disclosure; 
         FIG. 10  shows a further exemplary embodiment of a plunger for a graft tissue injector, for example, a graft tissue injector of  FIG. 1  in accordance with the present disclosure; 
         FIG. 11  shows a further exemplary embodiment of a cylinder of a graft tissue injector in accordance with the present disclosure; 
         FIG. 12  shows an exemplary embodiment of a retainment element for use with a graft tissue injector in accordance with the present disclosure; 
         FIG. 13  shows an exemplary embodiment of a container for a tissue cartridge in accordance with the present disclosure; 
         FIG. 14  shows a side view of the container and positioning elements and a tissue cartridge therein, in accordance with the present disclosure; 
         FIG. 15  shows a close-up view of a latch mechanism of the container of  FIG. 13  in accordance with the present disclosure; 
         FIG. 16  shows a stylized view of an exemplary kit including a graft tissue injector and a container having a pre-loaded tissue cartridge therein, in accordance with the present disclosure; 
         FIG. 17  shows an exemplary method of aspirating graft tissue into a graft tissue injector in accordance with the present disclosure; and 
         FIG. 18  shows an exemplary method of injecting graft tissue from a graft tissue injector in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and steps related to aspirating graft tissue into an injector and delivering (injector or ejecting) the graft tissue to a delivery location. Accordingly, the system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
     As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     The terms “corneal transplant” and “corneal graft” are used interchangeably herein to refer to a medical procedure, and the term “corneal graft tissue” is used herein to refer to the tissue used for the medical procedure of corneal transplant or corneal graft. 
     Referring now to the figures in which like reference designators are used for like elements, a graft tissue injector  10  (also referred to herein as an injector  10 ) is shown in  FIGS. 1-3 .  FIGS. 1 and 2  show the injector  10  in an injection configuration (or second configuration, when the injector  10  is in use) and  FIG. 3  shows the injector  10  in an aspiration configuration (or first configuration, when the injector  10  is in use). The injector  10  is configured for use in a medical procedure, such as in a Descemet&#39;s membrane endothelial keratoplasty (DMEK). In one embodiment, the corneal tissue injector is configured to aspirate a rolled piece of donor corneal tissue (referred to herein as “graft tissue”), including at least a portion of an endothelium and a Descemet&#39;s membrane, into the injector  10  for subsequent injection into an anterior chamber of a patient&#39;s eye (the aqueous humor-filled space inside the eye between the iris and the corneal endothelium). 
     Generally referring to the figures, in some embodiments the injector  10  generally includes a plunger  12 , a cylinder  14 , and includes or is configured to include a tissue cartridge  16  that is removably couplable to the cylinder  14 . When the injector  10  is assembled, the injector  10  has a bent shape, with a first portion having a first longitudinal axis  17  and a second portion having a second longitudinal axis  18  that is different than the first longitudinal axis  17 . In one embodiment, the first portion includes the plunger  12  and at least a portion of the cylinder  14  and the second portion includes at least a portion of the cylinder  14  and the tissue cartridge  16  (for example, as shown in  FIG. 1 ). To use the injector  10 , the user engages with the plunger  12  to retract the plunger  12  a distance within the cylinder  14 , thereby aspirating a graft tissue into the injector  10 . Conversely, to inject the graft tissue from the injector  10  into or at a delivery site, the user engages with the plunger  12  to advance the plunger  12  in an opposite direction a distance within the cylinder  14 , thereby ejecting the graft tissue from the injector  10 . Additionally, as is discussed in greater detail below, in one embodiment the tissue cartridge  16  is in a first position when graft tissue is aspirated into the graft tissue injector  10  (for example, as shown in  FIG. 3 ) and the tissue cartridge  16  is in a second position when graft tissue is injected from the graft tissue injector  10  (for example, as shown in  FIG. 2 ). 
     Referring now generally to  FIGS. 1-5 , the injector  10  generally includes a threaded plunger  12  and a threaded cylinder  14 . In one exemplary method of use, to aspirate graft tissue into the injector  10 , the plunger  12  is turned or rotated in a first direction (for example, counter-clockwise) to draw the plunger  12  within the cylinder  14  and away from the tissue cartridge  16  (for example, in the direction indicated by the arrow in  FIG. 1 ). Conversely, to inject the graft tissue from the injector  10  into or at a delivery site, the plunger  12  is turned in a second direction opposite the first direction (for example, clockwise) to advance the plunger  12  within the cylinder  14  toward the tissue cartridge  16  (for example, in the direction indicated by the arrow in  FIG. 2 ). 
     Referring now to  FIG. 4 , the plunger  12  is shown in greater detail. In one embodiment, the rotating plunger  12  has an elongated shape and generally includes a knob  19  and a shaft  20 . In one embodiment, the knob  19  is polygonal in cross section, but it will be understood that the knob  19  may have any suitable size, shape, and/or configuration that is easily graspable by the user. In one embodiment, the shaft  20  has an elongated shape and includes a first portion  22  coupled to, fused with, or extending from the knob  19  and a second portion  24  opposite the first portion  22 , the second portion  24  including a free end  26 . At least a portion of the shaft  20  is threaded. In one embodiment, an outer surface of the first portion  22  of the shaft  20  includes a continuous threading  28  extending from the knob  19  to a location between the first portion  22  and the second portion  24  of the shaft  20 . In one embodiment, the lower edge of the continuous threading  28  defines the boundary between the first portion  22  and the second portion  24 . However, it will be understood that the continuous threading may extend over the shaft  20  in any suitable location and/or over any suitable distance. As used herein, the term “continuous threading” refers to a threading pattern that extends around the shaft  20  at least once, or at least 360°, without break or interruption. Optionally, the shaft  20  may also include one or more areas, such as at or proximate the free end  26 , that include a material  30  such as rubber or a similar material, or simply protrusions from and formed of the same material as the shaft  20 , that enhances contact between the shaft  20  and an inner surface  31  of the cylinder  14 . This may prevent leaks and thereby help force liquid, and the graft tissue, from the injector  10  when the plunger  12  is rotated to advance the shaft  20  of the plunger  12  within the cylinder  14 . Further, in some embodiments the free end  26  includes or is coupled to an end piece of material  30 , which may be composed of, for example, rubber or a similar material. In some embodiments, the free end  26  is co-molded or formed with an integrated stopper that is composed of the same or different material than the shaft  20 . In some embodiments, the stopper is an end piece of material  30  that is affixed, adhered, or otherwise coupled to the free end  26 . 
     Referring now to  FIG. 5 , the cylinder  14  is shown in greater detail. In one embodiment, the cylinder  14  includes a body  32  and a connection extension  34  that is coupled to or extends from one end of the body  32 . In one embodiment, the body  32  has an elongated (and, in one embodiment, tubular or at least substantially tubular) shape and generally includes a first end  36 , a second end  38  opposite the first end  36 , and a chamber  40  therebetween. The chamber  40  is at least partially defined by the inner surface  31  of the body  32 . 
     Continuing to refer to  FIG. 5 , in one embodiment the first end  36  of the body  32  defines a first opening  42  and the second end  38  of the body  32  defines a second opening  44 , and the first opening  42  has a larger inner diameter than the second opening  44 . The first opening  42  and the second opening  44  are each in fluid communication with the chamber  40 . In some embodiments, the body  32  has a continuous, or at least substantially continuous, outer diameter and/or inner diameter along its entire length. In one non-limiting example, the chamber  40  has a continuous, or at least substantially continuous, diameter (that is, the body  32  has a continuous, or at least substantially continuous, inner diameter) along its length that is the same as, or at least substantially the same as, the inner diameter of the first opening  42 . In other embodiments, the body  32  has a varying outer and/or inner diameter. In one non-limiting example, a portion of the body  32  proximate the first end  36  has a larger outer diameter and a larger inner diameter than a portion of the body  32  proximate the second end  38  (for example, as shown in  FIGS. 5-7 ). In some embodiments, the cylinder  14  includes a finger grip or flange  46  extending from the first end  36  of the body and extending at least partially around the first opening  42 . 
     Continuing to refer to  FIG. 5 , in one embodiment the first opening  42  and at least a portion of the chamber  40  (for example, a portion of the chamber  40  that is proximate the first end  36  of the body  32 ) is sized and configured to receive at least a portion of the shaft  20  of the plunger  12  in close tolerance, such that fluid does not escape the injector  10  when the shaft  20  is rotated or advanced within the body  32 . Additionally, at least a portion of the body  32  includes threading  48  within the chamber  40 , on the inner surface  31  of the body  32 . In one embodiment, the body  32  includes threading  48  within the chamber  40  on the inner surface extending from the first opening  42  toward the second opening  44  and over a distance that is equal to, or at least substantially equal to (for example, within ±3 mm) the distance over which the first portion  22  of the shaft  20  of the plunger  12  is threaded. Further, the number of times the threading  28 ,  48  passes around 360° of the outer surface of the shaft  20  and the inner surface of the body  32 , respectively, depends on the characteristics of the threading  48 , such as pitch, size, thread angle, and the like. However, it will be understood that the threaded distances of the shaft  20  and the inner surface of the body  32  may be the same or different. The threading  48  in the chamber  40  is sized and configured to rotatably engage with the continuous threading  28  on the shaft  20  of the plunger  12 . Put another way, the threading of  28  of the shaft  20  is complementary to and engageable with the threading  48  in the chamber  40 . Thus, the shaft  20  of the plunger  12  may be screwed into, and rotatably movable within (that is, advanceable and retractable along the first longitudinal axis  17  of the cylinder  14 ), at least a portion of the chamber  40  of the body  32 . 
     Continuing to refer to  FIG. 5 , in one embodiment the connection extension  34  is coupled to or extends from the second end  38  of the body  32 . In one embodiment, the second end  38  of the body  32  includes an end wall  50  that surrounds or defines the second opening  44 . In one embodiment, the connection extension  34  extends from the end wall  50  at an acute angle to define the second longitudinal axis  18  of the injector  10 . In one embodiment, the connection extension  34  generally has a tubular shape, with a first end  52 , a second end  54  opposite the first end  52 , and a lumen  56  therebetween. The second end  54  defines an opening  58  in fluid communication with the lumen  56 . As shown in  FIG. 5 , in one embodiment the first end  52  of the connection extension  34  is coupled to or meets the end wall  50  of the body  32  such that the second opening  44  of the body  32  (and, therefore, the chamber  40 ) is in fluid communication with the lumen  56  and the opening  58  of the connection extension  34 . 
     Continuing to refer to  FIG. 5 , in one embodiment the connection extension  34  has an outer diameter that is less than at least the diameter of the end wall  50 . Likewise, in one embodiment the lumen  56  of the connection extension  34  has a diameter that is less than the diameter of the chamber  40  within at least a portion of the body  32  (that is, the connection extension  34  has an inner diameter that is less than the inner diameter of at least a portion of the body  32 ). Further, as is shown in  FIG. 5 , the connection extension  34  is canted relative to the body  32 . Put another way, the body  32  has a first longitudinal axis that is the same as, or at least substantially the same as, the first longitudinal axis  17  of the first portion of the injector  10  and the connection extension  34  has a second longitudinal axis that is the same as, or at least substantially the same as, the second longitudinal axis  18  of the second portion of the injector  10  (for example, as shown in  FIG. 1 ). In one embodiment, the first and second longitudinal axes  17 ,  18  intersect at an angle α of less than approximately 90° (±5°). In one embodiment, the angle α is between approximately 22.5° and approximately 67.5° (±5°). Thus, the injector  10  may be referred to as having a bent configuration, and this configuration may facilitate handling during both aspiration of the graft tissue and insertion of the graft tissue into the delivery site, such as the anterior chamber of the patient&#39;s eye. When the tissue cartridge  16  is coupled to the connection extension  34 , the tissue cartridge  16  lies along the same longitudinal axis as the tissue cartridge  16  (i.e. the second longitudinal axis  18 ). Likewise, although axes  17 ,  18  are not shown in  FIGS. 3 and 5 , it will be understood that the injector  10  has the same bent configuration regardless of how the tissue cartridge  16  is coupled to the connection extension  34  (or whether a tissue cartridge  16  is coupled to the connection extension  34 ). 
     Continuing to refer to  FIG. 5 , in one embodiment, the connection extension  34  and the body  32  are formed as a single, unitary piece. In another embodiment, the connection extension  34  is rigidly or flexibly coupled to the end wall  50  of the body  32 . In one embodiment the body  32  and the connection extension  34  are composed of the same material. For example, the entire cylinder  14  may be composed of a rigid material that is transparent and/or translucent, such as glass, plastic, or polymer. Thus, the connection extension  34  may be rigidly connected to or extend from the end wall  50  of the body  32  and, therefore, tissue cartridge  16  may be at a fixed position relative to the body  32  when connected to the connection extension  34 . In another embodiment, the body  32  and the connection extension  34  are composed of different materials. In one non-limiting example, the body  32  may be composed of a rigid first material (that is either opaque or transparent and/or translucent), such as glass, plastic, or polymer, whereas the connection extension  34  may be composed of a second material (that is either opaque or transparent and/or translucent) that is more flexible than, or that has a durometer that is less than, the material from which the body  32  is composed. This may allow some flexibility in the second portion of the injector  10  when in use. Put another way, when connected to the connection extension  34 , the tissue cartridge  16  may be at least somewhat movable relative to the body  32 . 
     Referring now to  FIG. 6 , the tissue cartridge  16  is shown in greater detail. In one embodiment, the tissue cartridge  16  generally has an elongated shape (and, in some embodiments, has a flute shape, as shown in  FIG. 8 ) and includes a first portion  60 , a second portion  62  opposite the first portion  60 , and a chamber  64  therebetween. The chamber  64  is defined by an inner surface of the tissue cartridge  16 . In one embodiment, the first portion  60  defines a first opening  66  and the second portion  62  defines a second opening  68 , and the first and second openings  66 ,  68  are each in fluid communication with the chamber  64 . In one embodiment, the first opening  66  has a larger diameter than the second opening  68 . Further, in one embodiment the first portion  60  has a first outer diameter and the second portion  62  has a second outer diameter that is less than the first outer diameter. The tissue cartridge  16  may also include a transition portion  69  between the first and second portions  60 ,  62  that has varying outer diameters between the first and second outer diameters. Likewise, in one embodiment the chamber  64  within the first portion  60  has a first diameter and the second portion  62  has a second diameter that is less than the first diameter (that is, the first portion  60  of the tissue cartridge  16  has an inner diameter that is greater than greater than the inner diameter of the second portion of the tissue cartridge  16 ). The chamber  64  within the transition portion  69  may also have varying diameters between the diameters of the first and second portions  60 ,  62  (that is, the transition portion  69  of the tissue cartridge  16  may have a varying inner diameter, or plurality of inner diameters, between the inner diameters of the first and second portions  60 ,  62 ). Put another way, in one embodiment the tissue cartridge  16  and chamber  64  therein have a tapered shape, and the second portion of the tissue cartridge may be an elongate tube of reduced diameter that is sized and configured to be at least partially inserted through a corneoscleral incision for injection and placement of the graft tissue within the anterior chamber of the patient&#39;s eye. Further, in some embodiments, the second portion  62  of the tissue cartridge  16  may have a blunt shape where the second portion  62  defines the second opening  68  (for example, as shown in  FIG. 6 ), and in other embodiments the second portion  62  has a beveled shape where the second portion  62  defines the second opening  68  (for example, as shown in  FIGS. 7 and 8 ). 
     Continuing to refer to  FIG. 6 , in one embodiment, the first portion  60  has a slight flute or flange shape surrounding the first opening  66 . Further, in one embodiment the first opening  66  of the tissue cartridge  16  and at least a portion of the chamber  64  (for example, the portion of the chamber  64  within the first portion  60  of the tissue cartridge  16 ) is sized and configured to fit over at least the second end  54  of the connection extension  34  of the cylinder  14 , such that the tissue cartridge  16  may be secured to the cylinder  14  by a friction fit and the chamber  64  of the tissue cartridge  16  is in fluid communication with the lumen  56  of the connection extension  34  and, therefore, the chamber  40  of the body  32 . Put another way, the inner diameter of the first opening  66  and at least a portion of the chamber  64  is slightly larger than the outer diameter of at least the second end  54  of the connection extension  34  such that the tissue cartridge  16  may be secured coupled to and removed from the connection extension  34  by hand. Further, in one embodiment the outer diameter of the second portion  62  of the tissue cartridge  16  is sized and configured to fit within the opening  58  of the connection extension  34  of the cylinder  14 , such that the tissue cartridge  16  may be secured to the cylinder  14  by a friction fit and the chamber  64  of the tissue cartridge  16  is in fluid communication with the lumen  56  of the connection extension  34  and, therefore, the chamber  40  of the body  32 . Put another way, the inner diameter of the opening  58  is slightly larger than the outer diameter of second portion  62  of the tissue cartridge  16 . As is described in greater detail below, in one embodiment the second portion  62  of the tissue cartridge  16  is engaged with the connection extension  34  when aspirating fluid and graft tissue (as shown in  FIG. 3 ), and the first portion  60  of the tissue cartridge is engaged with the connection extension  34  when injecting fluid and graft tissue (as shown in  FIGS. 1 and 2 ). Additionally, an inner and/or outer surface of the connection extension  34  and an inner and/or outer surface of the tissue cartridge  16  may optionally be matably threaded so the tissue cartridge  16  may be screwed onto or into the connection extension  34 . Further, in some embodiments, the injector  10  further includes a cap  70  that is removably coupled or couplable to the second end  62  of the tissue cartridge  16  to prevent graft tissue from escaping the chamber  64  through the second opening  68  once the injector  10  has been used to aspirate graft tissue and/or for pre-loaded tissue cartridges  16 A, as discussed in greater detail below. 
     Continuing to refer to  FIG. 6 , in one embodiment the tissue cartridge  16  is composed of a rigid material that is transparent and/or translucent, such as glass, plastic, or polymer. For example, in one embodiment the tissue cartridge  16  is composed of a clear polymer. This allows the tissue cartridge  16  to have the same inner diameter(s), but smaller outer diameter(s), than commercially known tissue cartridges composed of glass because certain polymers are more flexible and resistant to breakage than glass. Additionally, at least the portion of the second portion  62  surrounding the second opening  68  may be rounded or blunted to create an atraumatic tip. Alternatively, the portion of the second portion  62  surrounding the second opening may be beveled or include a bevel, which may facilitate insertion of the tissue cartridge into the eye. Thus, the tissue cartridge  16  of the present disclosure may be not only less traumatic when used to inject a tissue graft because of its reduced outer diameter(s) (at least the outer diameter of the second portion  62 ) and/or rounded tip, which allows for a smaller incision, but also more break-resistant than tissue cartridges  16  composed of glass. Further, in one embodiment at least a portion of the tissue cartridge  16  is coated with at least one layer of a lubricious material that lowers the coefficient of friction of that portion of the tissue cartridge  16 , such as polytetrafluoroethylene (PTFE), a nano-ceramic, or the like. In one embodiment, the lubricious material has a coefficient of friction of between approximately 0.1 and approximately 0.5 (±0.1). For example, a nano-ceramic coating that has a coefficient of friction that is at least 50% less than glass may be used on the inner surface and/or the outer surface of the tissue cartridge  16 , which reduces the likelihood of damage of the tissue graft and the patient&#39;s tissue during insertion. In one embodiment, both the inner surface (within the chamber  64 ) and the outer surface of the second portion  62  of the tissue cartridge  16  may be coated with at least one layer of a lubricous material or combination of lubricous materials. 
     Referring now to  FIGS. 7-9 , a further embodiment of a graft tissue injector  10  is shown (also referred to as injector  10 ). Unless otherwise noted, and where indicated by a common reference number, the components of the injector  10  in some embodiments are the same as are as described above regarding the injector  10  of  FIGS. 1-5  and will therefore not be discussed here for the sake of brevity.  FIG. 7  shows a side view of an exemplary injector  10  in an aspiration configuration;  FIG. 8  shows a side view of the injector  10  in an injection configuration; and  FIG. 9  shows an exemplary plunger  12  of the injector  10  in greater detail. 
     Referring now to  FIGS. 7 and 8 , the injector  10  has the same bent configuration as the injector  10  of  FIGS. 1-3 , and generally includes a cylinder  14  with a connection extension  34  and includes or is configured to include a tissue cartridge  16  that is removably couplable to the cylinder  14 . Further, the tissue cartridge  16  is removably couplable to the cylinder  14  in an aspiration configuration (as shown in  FIG. 7 ) or an injection configuration (as shown in  FIG. 8 ), as shown and described above regarding  FIGS. 1-6 . 
     Continuing to refer to  FIGS. 7 and 8 , the body  32  of the cylinder  14  includes a threading that is different than the threading  48  of the injector  10  of  FIGS. 1-3 . The threading shown in  FIGS. 7 and 8  is an interrupted threading  74  wherein the threaded track extends around only a portion (that is, less than the entire circumference or less than 360°) of the inner surface  31  of the cylinder  14 . The interrupted threading  74  thus defines a threaded portion  76  and an interrupted, non-threaded portion  78 . The non-threaded portion  78  has a width that is less than the diameter of the chamber  40  and extends longitudinally along at least a portion of the inner surface and, in some embodiments, passes through an entirety of the length of the interrupted threading  74 . 
     Referring now to  FIG. 9 , the plunger  12  is shown in greater detail. Unless otherwise noted, and where indicated by a common reference number, the components of the plunger  12  of  FIG. 9  are in some embodiments are the same as the plunger  12  of  FIG. 4  and will therefore not be discussed here for the sake of brevity. In one embodiment, the first portion  22  is not threaded, but does include a follower  80  that protrudes from a surface of the first portion  22  of the shaft  20 , as shown in  FIG. 9 . The follower  80  is sized and configured to not only travel within the channels of the threaded portion  76 , but also to pass through the non-threaded portion  78 . In one non-limiting example, the follower  80  has a width that is less than the width of the non-threaded portion  78 , and is oriented at non-orthogonal angle to the longitudinal axis  82  of the shaft  20 . For example, the follower  80  may be oriented such that it can pass through the channels of the threaded portion  76 . Further, in some embodiments, the follower  80  may be sized and oriented such that the plunger  12  may be used with the cylinder  14  of the injector  10  of  FIGS. 1-5  (that is, the follower  80  may be sized and configured to pass within the tracks of the continuous threading  48 ). 
     Continuing to refer to  FIG. 9 , in one exemplary method of use, the user draws the plunger  12  through the chamber  40  in a direction away from the tissue cartridge  16  to aspirate the graft tissue. For example, the user aligns the follower  80  with the non-threaded portion  78  and draws the plunger  12  longitudinally (that is, linearly along the first longitudinal axis  17  of the cylinder  14  without rotation) through the chamber  40  with the follower  80  passing through the non-threaded portion  78  and toward the first opening  42  of the body  32 . Following the non-threaded portion  78  allows the user to retract the plunger  12 , and thereby aspirate the graft tissue, faster than if the plunger  12  were rotated through the interrupted threading  74 . Further, in one exemplary method of use, the user rotates the plunger  12  through the channels of the threaded portion  76  in a direction toward the tissue cartridge  16  to controllably inject or deliver the graft tissue to the delivery site. For example, the user aligns the follower  80  with the channels of the threaded portion  76  and rotates the plunger  12  (for example, in the clockwise direction) to advance the plunger  12  through the chamber  40  with the follower  80  passing through the threaded portion  76  and toward the tissue cartridge  16 . Following the threaded portion  76  allows the user to advance the plunger  12 , and thereby inject the graft tissue, more slowly and in a more controlled manner than if the plunger  12  were rapidly advanced through the chamber  40  with the follower  80  in the non-threaded portion  78  of the interrupted threading  74 . 
     Referring now to  FIG. 10 , a further exemplary embodiment of a plunger  12  is shown. Unless otherwise noted, and where indicated by a common reference number, the components of the plunger  12  of  FIG. 10  in some embodiments are the same as are as described above regarding the plungers  12  of  FIGS. 4 and 9  and will therefore not be discussed here for the sake of brevity. In one embodiment, the plunger  12  of  FIG. 10  is substantially the same as the plunger  12  of  FIG. 4  and/or  FIG. 9 , except the plunger  12  of  FIG. 10  does not include the continuous threading  28  as in  FIG. 4  or the follower  80  as in  FIG. 9 . Instead, in some embodiments the plunger  12  of  FIG. 10  includes an engagement element  86  that extend around the outer surface of the first portion  22  of the shaft  20  by approximately one rotation (that is, approximately 360°±20°). In one non-limiting example, the engagement element  86  includes a plurality of spaced-apart elongated tabs or protrusions  88  that are aligned in approximately one threading rotation, to create a minimal threading pattern. Thus, in some embodiments the plunger  12  is configured to be used with the continuous threading  48  of the cylinder  14  of  FIGS. 1-5  (that is, the protrusions  88  of the engagement element  86  are configured to matingly engage the continuous threading  48  of the cylinder  14 ). In some embodiments, the plunger  12  is also configured to be used with the interrupted threading  74  of the cylinder  14  of  FIGS. 7 and 8 ; however, each protrusion  88  may have a length that is greater than the width of the non-threaded portion  78  of the interrupted threading  74  and, therefore, the plunger  12  could not be freely drawn longitudinally through the chamber  40 . The engagement element  86  may result in the plunger  12  being easier to manufacture than, for example, the continuous threading  28  of the plunger  12  and may also reduce the precision required when matching the continuous threading  28  of the plunger  12  with the continuous threading  48  of the cylinder  14 . 
     Referring now to  FIG. 11 , a further exemplary embodiment of a cylinder  14  for an injector  10  is shown. Unless otherwise noted, and where indicated by a common reference number, the components of the cylinder  14  of  FIG. 11  are in some embodiments the same as are as described above and will therefore not be discussed here for the sake of brevity. For example, in one embodiment, the external appearance of the cylinder  14  of  FIGS. 1-5  and the cylinder  14  of  FIGS. 7 and 8 . However, unlike the cylinder  14  embodiments discussed above, in one embodiment the cylinder  14  of  FIG. 11  includes an inner surface  31  that is free of threading or other structural features for engagement with the plunger  12 . Thus, any of the plungers discussed herein and/or other plungers may be used with the cylinder  14  of  FIG. 11 . To accommodate this, the diameter of the chamber  40 , at least within the portion of the body  32  proximate the first end  36 , may be somewhat larger than the diameter of the chamber  40  of the cylinder of  FIG. 1-5 or 7 or 8 , while still allowing a fit between the body  32  and at least a portion of the plunger in close tolerance to prevent the leakage of fluid. In one non-limiting example, the plunger may include an end piece of material  30  that is wide enough to contact the inner surface  31  of the cylinder  14 . 
     Referring now to  FIG. 12 , a retainment element  90  is shown. In one embodiment, the retainment element  90  is includes a sleeve portion  92  at a first end and a collar portion  94  at a second end opposite the first end. In one embodiment, the sleeve portion  92  is sized and configured to receive at least a portion of the flange  46  of the body  32  and the collar portion  94  is configured to receive a portion of the shaft  20  of the plunger  12 . Further, in one embodiment, the sleeve portion  92  is configured such that the sleeve portion  92  may be slid over and entrap at least a portion of the flange  46 , thereby preventing movement of the sleeve portion  92  and, therefore, the retainment element  90  in a direction parallel to the longitudinal axis  17  of the cylinder  14 . That is, the retainment element  90  is passed over the flange  46  in a direction that is orthogonal to the longitudinal axis  17  of the cylinder. Further, as the sleeve portion  92  is slid over the flange  46 , the collar portion  94  at least partially surrounds the shaft  20  of the plunger. In some embodiments, the plunger  12  includes threading, a follower, an engagement element, or other structural feature protruding from the shaft  20 . However, in some embodiments the collar portion  94  defines an opening or cut out that is sized to fit in close tolerance with the shaft  20 , or is at least smaller than the overall diameter of the shaft  20 , including the structure feature(s). Therefore, when the retainment element  90  is coupled to the cylinder  14  and the structural feature(s) of the shaft  20  are positioned within the chamber  40  of the cylinder  14 , the structural feature(s) cannot pass through the collar portion  94  and the retainment element  90  prevents the plunger  12  from retracting out of the cylinder  14 . 
     Thus, it will be appreciated that various combinations of cylinder  14  and plunger  12  are contemplated. For example, in some embodiments the injector  10  includes a cylinder  14  and a plunger  12 . In one embodiment, the cylinder  14  includes an inner surface  31  having continuous threading  28  and this cylinder  14  is configured to be used with any of the following plungers  12 : (1) a plunger  12  having complementary continuous threading  48  on at least a portion of the shaft  20 ; (2) a plunger  12  that is not threaded but includes a follower  80  on the shaft  20  that is sized and configured to travel within the continuous threading  28  within the cylinder  14 ; (3) a plunger  12  that includes an engagement element  86  that circumscribes the shaft  20  of the plunger  12  approximately once (for example, 360°±20°), the engagement element  86  including a plurality of protrusions  88  from the shaft  20  and being sized and configured to travel within the continuous threading  28  within the cylinder  14 ; and (4) a plunger without threading or other engagement feature. In one embodiment, the cylinder includes an inner surface  31  that has an interrupted threading  74 , the interrupted threading  74  including a threaded portion  76  and a non-threaded portion  78 , and this cylinder  14  is configured to be used with any of the following plungers  12 : (1) a plunger  12  having complementary continuous threading  48  on at least a portion of the shaft  20 ; (2) a plunger  12  that is not threaded but includes a follower  80  on the shaft  20  that is sized and configured to travel within the threaded portion  76  and to move longitudinally through the non-threaded portion  78 ; (3) a plunger  12  that includes an engagement element  86  that circumscribes the shaft  20  of the plunger  12  approximately once (for example, 360°±20°), the engagement element  86  including a plurality of protrusions  88  from the shaft  20  and being sized and configured to travel within the continuous threading  28  within the cylinder  14 ; and (4) a plunger without threading or other engagement feature. In one embodiment, the cylinder has an inner surface  31  that is free of threading or other structural feature protruding from or into the inner surface  31  and this cylinder  14  is configured to be used with any of the following plungers  12 : (1) a plunger  12  having complementary continuous threading  48  on at least a portion of the shaft  20 ; (2) a plunger  12  that is not threaded but includes a follower  80  on the shaft  20  that is sized and configured to travel within the threaded portion  76  and to move longitudinally through the non-threaded portion  78 ; (3) a plunger  12  that includes an engagement element  86  that circumscribes the shaft  20  of the plunger  12  approximately once (for example, 360°±20°), the engagement element  86  including a plurality of protrusions  88  from the shaft  20  and being sized and configured to travel within the continuous threading  28  within the cylinder  14 ; and (4) a plunger without threading or other engagement feature. Further, it will be understood that any of these combinations may include a retainment element  90 . 
     It will be further appreciated that more than one injector  10  may be used during a given procedure or series of procedures. For example, a user may use both a first injector  10  having a cylinder  14  without threading (as in  FIG. 11 ) to aspirate graft tissue into the tissue cartridge  16  (as the plunger may be rapidly withdrawn through the cylinder  14  to quickly aspirate the graft tissue) and a second injector  10  having a cylinder  14  and plunger  12  combination that is usable to controllably inject the graft tissue from the tissue cartridge  16  into the delivery site (for example, as shown in  FIGS. 1-5  and/or  FIGS. 7-10 ). In one non-limiting example, the user may aspirate the graft tissue using the first injector  10  (with the second portion  62  of the tissue cartridge  16  coupled to the connection extension  34 ), remove the tissue cartridge  16  from the first injector  10  and then secure the cap  70  to the tissue cartridge  16  to obstruct or cover the second opening  68 , and then connect the first portion  60  of the tissue cartridge  16  to the connection extension  34 . Once the user is ready to begin the graft tissue delivery procedure, the user may the remove the cap  70  from the tissue cartridge  16 . However, it will be understood that the user may use a single injector  10  or any combination of multiple injectors  10  and/or combinations of cylinder(s)  14  and plunger(s)  12 , depending on the type of procedure, time between aspiration and delivery of graft tissue, user preference, or the like. 
     Referring now to  FIGS. 13-15 , a container  95  for a tissue cartridge  16  is shown.  FIG. 13  shows a perspective view of an exemplary embodiment of a container  95 ,  FIG. 14  shows a side view of the container  95  with a containment element  96  and positioning elements  97  and a pre-loaded tissue cartridge  16 A therein, and  FIG. 15  shows a close-up view of a latch mechanism  98  of the container. In one embodiment, the container  95  is sized and configured to receive and retain a pre-loaded tissue cartridge  16 A (that is, a tissue cartridge  16  with graft tissue therein) and an amount of storage solution. Further, in one embodiment, the container  95  is a single-use container that, once opened, cannot be resealed (using the latch mechanism). In another embodiment, the container  95  is a multi-use container that can be opened and resealed many times. In some embodiments, the container  95 , with a pre-loaded tissue cartridge  16 A, and the injector  10  are sold together as a kit  99  (for example, as shown in  FIG. 14 ). In other embodiments, the container  95 , with or without a pre-loaded tissue cartridge  16 , is sold separately from the injector  10 . 
     Referring now to  FIG. 14 , in one embodiment, the container  95  generally includes a reservoir portion  100 , a lid  102 , and at least one latch mechanism  98  configured to couple the lid  102  to the reservoir portion  100 . The reservoir portion  100  and the lid  102  together define a chamber  104  within the container  95  that is sized and configured to hold the tissue cartridge  16  and, optionally, a volume of preservation solution. In one embodiment, the container  95  also includes at least one containment element  96  configured to physically block the first opening  66  of the tissue cartridge  16 A to prevent the graft tissue from escaping the tissue cartridge  16 A during storage, shipping, and the like, and at least one positioning element (for example, positioning elements  97 A-C shown in  FIG. 14 ) configured to be in contact with and secure the tissue cartridge  16 A within the container  95 . The containment element(s)  96  and the positioning elements  97 A- 97 C are not shown in  FIG. 13  for clarity, but it will be understood that the container  95  of  FIG. 13  may also include these elements. Alternatively, in some embodiments, the container  95  may not include containment and/or positioning elements. 
     Continuing to refer to  FIG. 14 , in one embodiment, the first positioning element  97 A extends downward from an inner surface of (and is fixedly coupled to or integrated with) the lid  102  toward the floor of the reservoir portion  100 , and the second positioning element  97 B extends upward from (and is fixedly coupled to or integrated with) the floor of the reservoir portion  100  toward the lid  102  (that is, the first and second positioning elements  97 A,  97 B extend in opposite directions toward the tissue cartridge  16 A). In one non-limiting example, each of the first and second positioning elements  97 A,  97 B includes a free end with a contoured or cutaway portion that sized and configured to retain at least a portion of the second portion  62  of the tissue cartridge  16 A and/or the cap  70 . In one non-limiting example, the third positioning element  97 C extends upward from (and is fixedly coupled to or integrated with) the floor of the reservoir portion  100  toward the lid  102  and includes a free end with a contoured or cutaway portion that sized and configured to retain at least a portion of the first portion  60  of the tissue cartridge  16 A. Thus, the tissue cartridge  16 A is secured in place between the positioning elements  97 A- 97 C within the chamber  104 , and is prevented from shifting or moving, when the container  95  is closed, with the lid  102  secured to the reservoir portion  100 . In one embodiment, the containment element  96  extends downward from an inner surface of (and is fixedly coupled to or integrated with) the lid  102  toward the floor of the reservoir portion  100  and is sized and shaped to block or obstruct at least a portion of the first opening  66  of the tissue cartridge  16 A. In one embodiment, the containment element  96  is sized and shaped to obstruct at least a portion of the first opening  66  of the tissue cartridge  16 A that is sufficient to prevent the graft tissue from escaping the tissue cartridge  16 A and into the chamber  104 . Likewise, a cap  70  may be coupled to the second portion  62  of the tissue cartridge  16 A that obstructs the second opening  68  and prevents the graft tissue from escaping the tissue cartridge  16 A and into the chamber  104  or out of the tissue cartridge  16 A once the tissue cartridge  16 A is removed from the container  95  and coupled to the injector  10 , at least until the user is ready to deliver the graft tissue to the delivery site. Additionally, when the container  95  is opened, the first positioning element  97 A and the containment element  96  are lifted away from the tissue cartridge  16 A with the lid  102 . However, the second and third positioning elements  97 B,  97 C maintain the position of the tissue cartridge  16 A. The connection extension  34  of the injector  10  can then be inserted into the first opening  66  of the tissue cartridge  16 A, without disrupting the tissue cartridge  16 A and while the cap  70  maintains obstruction of the second opening  68  to keep the graft tissue within the chamber  64  of the tissue cartridge  16 A. The cap  70  may remain on the tissue cartridge  16 A until the user is ready to deliver the graft tissue to the delivery site. However, in other embodiments, the container  95  includes a second containment element that is sized and configured to obstruct at least a portion of the first opening  68 . Further, it will be understood that the positioning elements  97 A- 97 C and/or the at least one containment element  96  may have other sizes, shapes, and configurations other than those shown. For example, in some embodiments the positioning elements  97 A- 97 C and/or the at least one containment element  96  may extend into the chamber  104  from locations on inner surfaces of the container  95  other than those shown and described, such as from a side wall of the reservoir portion  100 , from the inner surface of the lid  102  rather than the floor of the reservoir portion  100 , or the like. 
     Referring now to  FIG. 15 , in one embodiment, the latch mechanism  98  includes a latch  106  that is hingedly connected to clip elements  108  extending from an edge  110  of the lid  102 , and a tab  112  that extends orthogonally from the side wall  114  of the reservoir portion  100 . In one embodiment, the latch  106  includes an opening  116  that is sized and configured to accept at least a portion of the tab  112 , and the tab  112  includes a protrusion  118  extending downward from the tab  112  and away from the lid. Thus, when the tab  112  extends through the opening  116  of the latch  106  far enough that the protrusion  118  also passes through the opening  116 , the protrusion  118  holds the latch  106  in place to secure the lid  102  to the reservoir portion  100 . Put another way, the latch  106  is configured to be securably snapped onto the tab  112 . However, it will be understood that coupling elements other than the latch mechanism  98  shown in  FIGS. 13 and 14  may be used, such as a clamp, a clasp, a tab and groove, a snap, or other suitable mechanism. Further, in some embodiments, words, symbols, or other indicia may be printed, etched, integrally molded with, or otherwise displayed on the lid  102 , reservoir portion  100 , or other portion of the container. In one non-limiting example, the lid  102  may be molded with words “single use only” in relief; however, it will be understood that any text or indicia may be used. 
     Referring now to  FIG. 16 , an exemplary kit is shown, such as a kit for performing corneal transplant. In one embodiment, the kit  99  includes a container  95  with a pre-loaded tissue cartridge  16 A therein, and an injector  10 . However, it will be understood that the kit  99  may, in some embodiments, include additional components and/or a tissue cartridge  16 A that is not pre-loaded (that is, a tissue cartridge  16  that does not include graft tissue therein at the time of sale). 
     Referring now to  FIGS. 17 and 18 , an exemplary method of delivering graft tissue to a delivery site is shown. In one embodiment, the method may include aspirating graft tissue into an injector  10  (as shown in  FIG. 17 ) and then delivering or injecting the graft tissue from the injector  10  into or at the delivery site (as shown in  FIG. 18 ). In another embodiment, such as when the injector  10  is used with a pre-loaded tissue cartridge  16 A, the method may include only delivering or injecting the graft tissue from the injector  10  into or at the delivery site (as shown in  FIG. 18 ). 
     Referring now to  FIG. 17 , an exemplary method of aspirating a graft tissue with the injector  10  is shown. The graft tissue may be contained within a volume of suitable solution, such as balanced saline solution (BSS) or similar fluid. In use, the injector  10  may be partially filled with a solution suitable for containing the graft tissue without damage, such as BSS. Further, before aspirating the graft tissue, the user ensures the plunger  12  is in a position such that the shaft  20  may be further retracted within the chamber  40  in a direction away from the tissue cartridge  16 . That is, the shaft  20  must be retracted within the chamber  40  in a direction opposite the tissue cartridge  16  at least over a distance sufficient to aspirate the graft tissue. In one non-limiting example, the user ensures the shaft  20  is fully advanced within the chamber  40  of the body  32  such that the free end  26  of the shaft  20  is in contact with an inner surface of the end wall  50  and/or that the rotating plunger  12  cannot be further advanced within the chamber  40  by rotating the knob in a first or clockwise direction. However, it will be understood that in some examples the shaft  20  is less than fully advanced. 
     Continuing to refer to  FIG. 17 , in a first step  150  the user engages the tissue cartridge  16  with the connection extension  34  of the cylinder  14  in a first or aspiration configuration. In one embodiment, the user inserts at least a portion of the second portion  62  of the tissue cartridge  16  into the opening  58  of the connection extension  34 , thereby leaving the first portion  60 , and the first opening  66 , of the of the tissue cartridge  16  available for aspirating fluid and graft tissue into the chamber  64  of the tissue cartridge  16  (for example, as shown in  FIG. 3 ). The first opening  66  is wider than the second opening  68 , which may reduce the likelihood of graft tissue damage during aspiration. 
     Continuing to refer to  FIG. 17 , in a second step  152  the user positions the first opening  66  of the tissue cartridge  16  proximate the graft tissue. In one embodiment, the graft tissue is a narrow, elongate Descemet&#39;s roll formed spontaneously after a circular layer of endothelium/Descemet&#39;s membrane is removed from the donor posterior stroma, and is stained with blue stain such as 0.06% trypan blue. To aspirate the graft tissue through the first opening  66  and into the chamber  64  in a third step  154 , in one embodiment (for example, using the injector  10  of  FIGS. 1-4 ) the user slowly rotates the knob  19  of the plunger  12  in a second direction opposite the first direction (for example, the counter-clockwise direction). Rotation of the knob  19  in the second direction retracts the shaft  20  within the chamber  40  of the body  32  in a direction that is away from the tissue cartridge  16 , which in turn draws in the solution in which the graft tissue is located (for example, BSS), as well as the graft tissue. In another embodiment (for example, using the injector  10  of  FIGS. 9-11 ), the user retracts the plunger  12  longitudinally (that is, linearly along the first longitudinal axis  17  of the cylinder  14  without rotation) in a direction that is away from the tissue cartridge  16 , which in turn draws in the solution in which the graft tissue is located (for example, BSS), as well as the graft tissue. In one embodiment, the first opening  66  of the tissue cartridge  16  is sized and configured such that the graft tissue may pass without resistance through the first opening  66  and into the chamber  64 . Thus, upon aspiration of the graft tissue, the graft tissue is located within the chamber  64  of the tissue cartridge  16  within BSS or similar fluid. The plunger  12  allows the user to aspirate the graft tissue more slowly and with more precision and control than offered by currently known syringe-type injectors. 
     Referring now to  FIG. 18 , an exemplary method of injecting graft tissue from the injector  10  is shown. In some embodiments, the method of  FIG. 18  begins after the method of  FIG. 17  is performed. In other embodiments, such as when the injector  10  is used with a pre-loaded tissue cartridge  16 A (such as is discussed above regarding  FIGS. 13-15 ), the user may simply begin the method of  FIG. 18  by using the pre-loaded tissue cartridge  16 A. In any embodiment, in a first step  160 , the user engages the tissue cartridge  16  with the connection extension  34  of the cylinder  14  in a second or injection configuration. In one embodiment, the user inserts at least a portion of the connection extension  34  into the first opening  66  of the tissue cartridge  16 , thereby leaving the second portion  62 , and the second opening  68 , of the tissue cartridge  16  free to insert into the patient&#39;s eye and deliver or inject the graft tissue (as shown in  FIGS. 1 and 2 ). 
     Continuing to refer to  FIG. 18 , in a second step  162 , at least a portion of the second portion  62  of the tissue cartridge  16  (that is, the narrow tip of the tissue cartridge  16 ) is inserted through an incision, such as a scleral or corneal incision, and into the anterior chamber of the patient&#39;s eye. In a third step  164 , the second opening  68  of the tissue cartridge  16  is positioned at a target delivery site within the anterior chamber. In a fourth step  166 , in one embodiment (for example, using the injector  10  of  FIGS. 1-4 ) the user slowly rotates the knob  19  of the plunger  12  in the first direction (for example, the clockwise direction), which advances the shaft  20  within the chamber  40  of the body  32  in a direction that is toward the tissue cartridge  16 , which in turn ejects the fluid (for example, BSS) and the graft tissue from the tissue cartridge  16  and into the anterior chamber of the patient&#39;s eye. In another embodiment (for example, using the injector  10  of  FIGS. 7-9 ), the user rotates the plunger  12  in a direction, such as clockwise, to advance the shaft  20  in a direction toward the tissue cartridge  16 , which ejects fluid and the graft tissue from the tissue cartridge  16  and into the anterior chamber of the patient&#39;s eye. Further, the narrow diameter of the chamber  64  within the second portion  62  of the tissue cartridge  16  may help align the graft tissue in the proper orientation for delivery to the target delivery site. Rotating the plunger  12  to advance the plunger  12  allows the user to inject the graft tissue into the anterior chamber more slowly and with more precision and control than offered by currently known syringe-type injectors. Additionally, injecting the graft tissue and fluid more slowly into the anterior chamber may help prevent over-pressurization of the anterior chamber during delivery. 
     Other embodiments may include: 
     Embodiment 1 
     An injector comprising: a cylinder; and a plunger at least partially located within the cylinder, the plunger being rotatably and longitudinally advanceable within the cylinder. 
     Embodiment 2 
     The injector of Embodiment 1, wherein rotating the plunger in a first direction within the cylinder controllably aspirates a graft tissue into the injector and rotating the plunger in a second direction opposite the first direction controllably ejects the graft tissue from the injector. 
     Embodiment 3 
     The injector of Embodiment 1, wherein the cylinder includes a body having: a first portion defining a first opening; a second portion opposite the first portion, the second portion defining a second opening; and a chamber, the chamber being in fluid communication with the first opening and the second opening. 
     Embodiment 4 
     The injector of Embodiment 3, wherein the chamber has a first diameter within the first portion of the body and the chamber has a second diameter within the second portion of the body, the first diameter being greater than the second diameter. 
     Embodiment 5 
     The injector of Embodiment 3, wherein the cylinder further includes a connection extension having: a first end coupled to the second portion of the body; a second end opposite the first end, the second end defining an opening; and a lumen, the lumen being in fluid communication with the second opening of the body and the second opening of the connection extension. 
     Embodiment 6 
     The injector of Embodiment 5, wherein the body has a first longitudinal axis and the connection extension has a second longitudinal axis that is different than the first longitudinal axis. 
     Embodiment 7 
     The injector of Embodiment 6, wherein the second longitudinal axis is oriented at an angle from the first longitudinal axis, the angle being between approximately 22.5° and approximately 67.5°. 
     Embodiment 8 
     The injector of Embodiment 5, wherein the plunger includes: a shaft having a first portion and a second portion opposite the first portion, the second portion having a free end; and a knob coupled to the first portion of the shaft, an outer surface of at least a portion of the first portion of the shaft being threaded. 
     Embodiment 9 
     The injector of Embodiment 8, wherein at least a portion of an inner surface of the body within the chamber is threaded, the threaded portion of the shaft of the plunger being matably engageable with the threaded portion of the inner surface of the body. 
     Embodiment 10 
     The injector of Embodiment 5, further comprising a tissue cartridge including: a first portion defining a first opening and having a first outer diameter; a second portion opposite the first portion and defining a second opening, the second portion having a second outer diameter that is less than the first outer diameter; and a chamber, the chamber being in fluid communication with the first opening of the tissue cartridge and the second opening of the tissue cartridge. 
     Embodiment 11 
     The injector of Embodiment 10, wherein the first opening of the tissue cartridge has a first diameter and the second opening of the tissue cartridge has a second diameter that is less than the first diameter. 
     Embodiment 12 
     The injector of Embodiment 11, wherein: the connection extension has an outer diameter that is slightly smaller than the diameter of the first opening of the tissue cartridge, such that the connection extension is removably insertable within the first opening of the tissue cartridge and securable therein by friction fit; and the connection extension has an inner diameter that is slightly larger than the outer diameter of the second portion of the tissue cartridge, such that the second portion of the tissue cartridge is removably insertable within the connection extension and securable therein by friction fit. 
     Embodiment 13 
     The injector of Embodiment 10, wherein the tissue cartridge is composed of polymer. 
     Embodiment 14 
     The injector of Embodiment 13, wherein the body is composed of a material from the group consisting of plastic, glass, and polymer. 
     Embodiment 15 
     The injector of Embodiment 10, wherein at least a portion of the tissue cartridge is coated with at least one layer of a lubricious material. 
     Embodiment 16 
     The injector of Embodiment 15, wherein both an outer surface and an inner surface within the chamber of the second portion of the tissue cartridge are coated with the at least one layer of nano-ceramic material. 
     It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and the accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, delivery of corneal graft tissue to a delivery site. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention.