Abstract:
A vitrectomy probe includes a hand-graspable body and an external tube extending from the hand-graspable body and sized to penetrate an eye of a patient during an ocular surgery. In an aspect, the external tube includes a closed end and a plurality of ports sized to receive vitreous material. In another aspect, an internal tube has a first cutting edge facing in a proximal direction and a second cutting edge facing in a distal direction. The first cutting edge oscillates across the port of the external tube to cut tissue in the port with the first cutting edge when the internal tube moves in the proximal direction and to cut tissue in the port with the second cutting edge when the internal tube moves in the distal direction.

Description:
PRIORITY CLAIM 
     This application claims the benefit of priority of U.S. Provisional Patent Application Ser. No. 61/738,509 titled “MULTI-PORT VITRECTOMY PROBE WITH DUAL CUTTING EDGES,” filed on Dec. 18, 2012, whose inventors are Oded M. Nissan and Dana Tendler, which is hereby incorporated by reference in its entirety as though fully and completely set forth herein. 
    
    
     BACKGROUND 
     The present invention pertains to vitrectomy probes, systems, and methods. More particularly, but not by way of limitation, the present invention pertains to vitrectomy probes, systems, and methods utilizing a multi-port member or a dual cutting edge design. 
     Microsurgical procedures frequently require precision cutting and/or removing various body tissues. For example, certain ophthalmic surgical procedures require cutting and removing portions of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic fibrils that are often attached to the retina. Therefore, cutting and removing the vitreous must be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself. In particular, delicate operations such as mobile tissue management (e.g. cutting and removal of vitreous near a detached portion of the retina or a retinal tear), vitreous base dissection, and cutting and removal of membranes are particularly difficult. 
     The use of microsurgical cutting probes in posterior segment ophthalmic surgery is well known. These cutting probes typically include a hollow outer cutting member, a hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, and a port extending radially through the outer cutting member near the distal end thereof. Vitreous humor and/or membranes are aspirated into the open port, and the inner member is actuated, closing the port. Upon the closing of the port, cutting surfaces on both the inner and outer cutting members cooperate to cut the vitreous and/or membranes, and the cut tissue is then aspirated away through the inner cutting member. 
     While the conventional design is suitable for many applications, increases in cutting rate or in aspiration rate may increase efficiency of the surgical procedures, providing benefits to both the patients and the surgeon. 
     The present disclosure is directed to addressing one or more of the deficiencies in the prior art. 
     SUMMARY 
     In an exemplary aspect, the present disclosure is directed to a vitrectomy probe including a hand-graspable body and an external tube extending from the hand-graspable body and sized to penetrate an eye of a patient during an ocular surgery. The external tube may include a closed end and a port sized to receive vitreous material. The vitrectomy probe also includes an internal tube having a first cutting edge facing in a proximal direction and a second cutting edge facing in a distal direction. The internal tube may be disposed within the external tube so that the first cutting edge oscillates across the port of the external tube to cut tissue in the port with the first cutting edge when the internal tube moves in the proximal direction and to cut tissue in the port with the second cutting edge when the internal tube moves in the distal direction. A motor drives the internal tube in a reciprocating motion relative to the external tube. 
     In an aspect, the external tube comprises a plurality of ports. In an aspect, the plurality of ports is disposed at the distal end of the external tube and is evenly spaced about the circumference of the external tube. In an aspect, the internal tube comprises a distal portion and a proximal portion, where the distal portion comprises the first cutting edge facing the proximal portion and comprises the second cutting edge facing in the distal direction. In an aspect, the distal portion is rigidly fixed to and spaced apart from the proximal portion by an extending shaft. 
     In another exemplary aspect, the present disclosure is directed to a vitrectomy probe including a hand-graspable body and an external tube extending from the body and sized to penetrate an eye of a patient, the external tube having a closed end, the external tube having a plurality of ports sized to receive vitreous of an eye. An internal tube may be disposed within and axially slidable relative to the external tube. The internal tube may have a first cutting edge facing in a distal direction, and may be disposed within the external tube so that the first cutting edge oscillates across the port of the external tube to cut tissue in the plurality of ports with the first cutting edge when the internal tube moves in the distal direction. A motor may drive the internal tube in a reciprocating motion. 
     In an aspect, the internal tube includes a second cutting edge facing in a proximal direction, the internal tube being disposed within the external tube so that the second cutting edge oscillates across the port of the external tube to cut tissue in the port with the second cutting edge when the internal tube moves in the proximal direction. In an aspect, the internal tube comprises a distal portion and a proximal portion, the distal portion comprising the first cutting edge facing the distal direction and comprising the second cutting edge facing in the proximal direction. 
     In another exemplary aspect, the present disclosure is directed to a method of cutting vitreous with a vitrectomy probe. The method may include axially sliding an internal cutting tube within an external cutting tube in a proximal direction to cut vitreous with a proximally facing cutting edge on the internal cutting tube, axially sliding the internal cutting tube within the external cutting tube in a distal direction to cut vitreous with a distally facing cutting edge on the internal cutting tube, and aspirating the cut vitreous through the internal cutting tube. 
     In an aspect, the method includes cutting the vitreous with cross-blades extending across a first open distal end of a distal portion of the internal cutting tube, and aspirating the vitreous past cross-blades extending across a second open distal end of a proximal portion of the internal cutting tube. In an aspect, the method may include receiving vitreous into a plurality of ports of the external cutting tube for cutting by the internal cutting tube. In an aspect the method may include pulling a distal portion of the internal cutting tube in the proximal direction with a central bar extending between the distal portion of the internal cutting tube and a proximal portion of the internal cutting tube. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate embodiments of the devices and methods disclosed herein and together with the description, serve to explain the principles of the present disclosure. 
         FIG. 1  is an illustration of an exemplary surgical system according to one aspect of the present disclosure consistent with the principles and teachings described herein. 
         FIG. 2  is a box diagram of aspects of the exemplary surgical system of  FIG. 1  according to one aspect described herein. 
         FIG. 3  is an illustration of an exemplary vitrectomy probe in cross-section operable in accordance with the principles and teachings described herein. 
         FIG. 4  is an illustration of an exemplary distal end of the vitrectomy probe in partial cross-section consistent with the principles and teachings described herein. 
         FIG. 5  is an illustration of an exemplary outer cutting tube consistent with the principles and teachings described herein. 
         FIG. 6  is an illustration of an exemplary inner cutting tube in partial cross-section consistent with the principles and teachings described herein. 
         FIGS. 7A-7D  are illustrations showing the inner and outer cutting tubes in partial cross-section and in different positions during a cutting cycle. 
         FIG. 8  is an illustration of an exemplary inner cutting tube consistent with the principles and teachings described herein. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described systems, devices, and methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the systems, devices, and/or methods described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts. 
     The present disclosure is directed to surgical devices, systems, and methods for performing ophthalmic surgeries. The devices, systems, and methods are arranged and configured to increase a cut rate and/or an aspiration rate during a vitrectomy procedure. To accomplish this, the system incorporates a cutter that includes multiple outer ports and includes a cutter that cuts in both directions during a cutting cycle. This may result in shorter surgeries overall and may result in faster cut rates and aspiration rates that may lead to decreased traction in the vitreous. 
       FIG. 1  illustrates a vitrectomy surgical system, generally designated  100 , according to an exemplary embodiment. The surgical system  100  includes a base housing  102  and an associated display screen  104  showing data relating to system operation and performance during a vitrectomy surgical procedure. The surgical system  100  includes a vitrectomy probe system  110  that includes a vitrectomy probe  112 . 
       FIG. 2  is a schematic of the vitrectomy probe system  110 . The probe system  110  includes the vitrectomy probe  112 , a pneumatic pressure source  120 , a probe driver shown as an adjustable directional on-off pneumatic driver  122 , a muffler  124 , and a controller  126 . As can be seen, the source  120 , the driver  122 , the muffler  124 , and the probe  112  are in fluid communication with each other along lines representing flow paths or flow lines. The controller  126  is in electrical communication with the driver  122 . 
       FIG. 3  shows a cross-sectional illustration of an exemplary vitrectomy probe, referenced by the numeral  112 . In this example, the vitrectomy probe  112  is a pneumatically driven probe that operates by receiving pneumatic pressure alternating through first and second ports  140  and  142 . The probe  112  includes as its basic components a cutter  150  comprising an outer cutting tube  152 , an inner cutting tube  154 , and a probe actuator or motor shown here as a reciprocating air driven diaphragm  156 , all partially encased by a housing  158 . The housing  158  includes an end piece  160  at the probe proximal end with the first and second air supply ports  140 ,  142  and one suction port  162 . 
     As can be seen, the cutter  150  extends from the housing  158  and includes a distal end  166 .  FIG. 4  shows the distal end  166  of the cutting tube  150  in greater detail. It is a partial cross-sectional view showing the outer cutting tube  152  in cross-section and showing the inner cutting tube  154  in place in the outer cutting tube  152 . Referring to  FIG. 4 , the inner cutting tube  154  fits within the outer cutting tube  152  in a coaxial manner, and the inner tube is axially moveable relative to the outer cutting tube.  FIG. 5  shows the distal end of the outer cutting tube  152  in an isometric view. 
     Referring to both  FIGS. 4 and 5 , the outer cutting tube  152  has a closed end  164  and a plurality of outer ports  168  that receive tissue, such as ophthalmic tissue. The outer ports  168  are in fluid communication with an inner channel  170  of the outer cutting tube  152 . In the exemplary embodiment shown, the outer cutting tube  152  includes four ports evenly spaced about the circumference of the outer tube  154 . However, different numbers of ports may be used. Conventional systems employ a single port on a single side. However, multiple ports may allow a surgeon to perform surgeries in a more efficient manner because the surgeon need not rotate the vitrectomy device to align the port in a desired radial direction. In the example shown in  FIGS. 4 and 5 , the ports  168  are oval shaped and are configured to cooperate with the inner cutting tube  154  to cut tissue during an ophthalmic surgery. In some embodiments, the distal and proximal edges of the ports  168  are sharpened to aid in the cutting of the vitreous. The inner distance from the distal most edge of the ports  168  to the proximal facing wall of the closed end  164  may be a distance D. 
       FIGS. 4 and 6  show the inner cutting member  154  in greater detail.  FIG. 4  shows a side view of the inner cutting member  154  disposed within the sectioned outer cutting member  152 .  FIG. 6  shows a partial cross-sectional view of the cutting member  154 . 
     The inner cutting tube  154  has a main tube  172  forming proximal portion and has a cutting element or cutting head  174 . The main tube  172  is a cylindrical tube having an inner bore  180  and an open end  182 . In this embodiment, the open end  182  includes a tapered leading edge  184  on its inner diameter. This facilitates the passage of tissue, as is explained further below. The inner bore  180  is in fluid communication with an aspiration line (not shown) that connects to a vacuum pressure that pulls tissue into the plurality of outer ports  168  when the inner cutting tube  154  is located away from the ports  168 . The inner cutting tube  154  moves within the inner channel  170  of the outer cutting tube  152  in a cyclic motion to drive the cutting head  174  to cut tissue that is pulled into the outer ports  168  by the aspiration system. The ophthalmic tissue received by the outer ports  168  is preferably vitreous or membranes. 
     The cutting head  174  includes an anterior portion  190  and a posterior portion  192 . These portions  190 ,  192  are spaced apart from each other and are rigidly secured together by a connecting portion  194 , which in this embodiment is disclosed as a centrally disposed shaft. 
     The posterior portion  192  is disposed within the inner bore  180  of the main tube  172  and includes a plurality of cross-blades  200 . These cross-blades  200  radially extend from a central intersection  202 . The cross-blades  200  are sized so that their outer-facing edges  204  engage or connect to the interior of the inner bore  180  of the main tube  172 , holding the cutting head  174  in place. These may be secured in place using welding, brazing, cements, or adhesives, friction fits, or other methods. In the embodiment shown, the cross-blades  200  of the posterior portion  192  of the cutting head  174  extend a sufficient length into the main tube  172  to anchor the cutting head  174  against displacement from the main tube  172  during the cutting cycle. Because the exemplary posterior portion  192  includes three radially extending cross-blades, the inner bore  180  of the main tube  172  is divided into three passages, each forming about a third of the area of the main tube  172 . While shown with three cross-blades, other embodiments include two cross blades, while yet others include four or more. 
     The anterior portion  190  is spaced from the posterior portion  192  and from the open end  182  of the main tube  172 . It includes an outer cutting blade  208  and anterior radial cross-blades  210  that converge at an intersection  212 . The outer cutting blade  208  is a cylindrically shaped cutting blade having an outer diameter that substantially matches the outer diameter of the main tube  172 . As such, it is configured to also slide within the inner bore  170  of the outer cutting tube  152 . The outer cutting blade  208  includes a distal cutting edge  216  and a proximal cutting edge  218  separated by body having a length L. In some embodiments, the distal and proximal cutting edges  216 ,  218  are tapered or sharpened on their inner diameters in order to cleanly cut vitreous with a minimal of tissue shearing. This may reduce trauma to the vitreous remaining in the eye. 
     These anterior cross-blades  210  support or carry the outer cutting blade  208  and radially extend from the central intersection  212 . Like the cross-blades  200 , the cross-blades  210  are sized so that their outer-facing edges engage or connect to the interior of the outer cutting blade  208 . In the embodiment shown, the cross-blades  200  extend the length L of the outer cutting blade  208 ; however, in other embodiments, the cross-blades do not have the same length as the outer cutting blade  208 . 
     In the example shown in  FIG. 6 , the anterior portion  190  includes four radially extending cross-blades  210 , which divides an inner bore formed by the outer cutting blade  208  into four passages, each forming about a quarter of the area of the inner diameter of the outer cutting tube  208 . Accordingly, the area of each of the four passages is smaller than the area of each of the three passages formed by the posterior portion  192 . These anterior cross-blades  210  therefore, may cut tissue, such as vitreous into segments small enough to easily pass beyond the posterior cross-blades  200  into the inner bore  180  of the main tube  172 . In the embodiment shown, the main tube  172  and the outer cutting blade  208  have substantially the same inner diameter and substantially the same outer diameter. While shown with four anterior cross-blades  210 , other embodiments include two or three cross blades, while yet others include five or more. In the embodiment shown, each of the cross-blades may include a sharpened leading surface on one or both edges to contribute to cutting the vitreous into small segments for easy aspiration. 
     The connecting portion  194  extends between and connects the intersection  202  and the intersection  212 . In this embodiment, it extends along the central axis of the inner cutting tube  154 . Other embodiments have two or more connecting portions that secure the anterior portion with the cutting blade  208  to the main tube  172 . 
     The area between the anterior and posterior portions  190 ,  192 , is referred to herein as the posterior cavity  222 . In the embodiment shown, the posterior cavity  222  has a longitudinal length greater than the longitudinal length of the ports  168 . Accordingly, tissue may enter the ports  168  into the posterior cavity  222  unimpeded when the posterior cavity is aligned with the ports  168 . In other embodiments, however, the posterior cavity  168  has a longitudinal length smaller than the longitudinal length of the ports  168 . In these embodiments, the full length of the port  168  may not be open to receive tissue at the same time. 
       FIGS. 7A-7D  show a cutting cycle of the vitrectomy cutter  150 .  FIG. 7A  represents the portion of a cutting cycle when the inner cutting tube  172  is in the proximal position. In this position, the ports  168  are open, and vacuum pressure in the inner cutting tube  154  pulls tissue into the ports  168  and into the inner channel  170  of the outer cutting tube  152 . 
     As shown in  FIG. 7B , inner cutting tube  154 , including the outer cutting blade  208  on the anterior portion of the cutting tube  154 , travels distally toward distal end  164  of the outer cutting tube. As it moves, the distal cutting edge  216  cuts vitreous tissue that has entered the ports  168 , severing the tissue within the inner channel  170 . The severed tissue is pulled through the inner bore  180  of the inner cutting tube  154  by the aspiration system. At the same time, the vacuum pressure from the aspiration system continues to pull tissue into the ports  168  and into the inner channel  180 . The inner cutting tube  154  moves distally until the outer cutting blade  208  is beyond the ports  168 , as shown in  FIG. 7C . At this point, the posterior cavity  222  is aligned with the ports  168  and the tissue is entering through the ports  168  and into the posterior cavity  222  formed between the anterior portion and the posterior portion of the cutting head  174 . In some exemplary embodiments, the distance D ( FIG. 4 ) showing the distance between the distal most edge of the ports  168  and the end  164  of the outer cutting tube is equal to or greater than the length L ( FIG. 4 ) of the outer cutting blade  208 . Accordingly, the outer cutting blade  208  can entirely pass beyond the ports  168  to permit vitreous to enter unimpeded. 
     As shown in  FIG. 7D , the inner cutting tube  154  then moves in the proximal direction, drawing the outer cutting blade  208  in the proximal direction. As the outer cutting blade  208  moves in the proximal direction, the proximal cutting edge  218  cuts vitreous tissue that has entered the posterior cavity  222  through the ports  168 , severing the tissue within the inner channel  170 . The severed tissue is pulled through the inner bore  180  of the inner cutting tube  154  by the aspiration system, and the inner cutting tube  154  returns to the position shown in  FIG. 7A . 
     Here, the tissue cut by the anterior portion  190  of the cutting head  174  may be diced into small segments by the anterior cross-blades  210 . Since the segments defined by the area between cross-blades  210  in the anterior portion  190  is smaller than the segments defined by the area between cross-blades  200  in the posterior portion  192 , tissue segments may more easily aspirate past the posterior cross-blades  200 . Any tissue that is too large to pass the posterior cross-blades  200  may be further severed by the cross-blades  200 . 
     Because the cutting action occurs as the inner blade moves in both the proximal and the distal directions, the cutting blade performs a dual-action cutting cycle. This may double the cut rate of the vitrectomy probe. For example, while still operating the motor of the vitrectomy probe  112  at 10000 cycles/min., the effective cut rate is 20000 cycles/min since each cycle provides both an anterior cut and a posterior cut. 
     With reference now to both  FIGS. 3 and 4 , the inner cutting tube  154  is driven by air pressure directed on opposing sides of the diaphragm  156 . In one example of operation, if air pressure is increased at the first port  140 , the diaphragm  156  will move distally, displacing the inner cutting tube  154  relative to the outer cutting tube  152 , thereby moving the cutting head  174  in the distal direction, and cutting tissue with the distal cutting edge  216 . This cuts any vitreous material which may have been aspirated into the tissue-receiving outer port  168  and aligns the posterior cavity  222  with the ports  168 . Venting the pressure at the first port  140  and increasing the pressure at the second port  214  moves the diaphragm  156  proximally, moving the outer cutting blade  208  in the proximal direction, cutting any vitreous material which may have entered into the posterior cavity. Its worth noting that other embodiments include alternative probe actuators. For example, some embodiments include a piston motor in place of a diaphragm. In this type of embodiment, the cutter  150  is arranged so that movement of the piston also moves the inner cutting tube  154  of the cutter  150 . Yet other embodiments include other types of pneumatic or electric motors that drive the inner cutting tube  154 . 
     Returning to  FIG. 2 , in the example shown, the vitrectomy probe system&#39;s pneumatic driver  122  is a standard four-way on-off valve. As is commonly known, the pneumatic driver  122  has a solenoid that operates to move the driver to one of the two on-off positions depicted in the example of  FIG. 2 . Here, the pneumatic driver  122  is in a position to provide pneumatic pressure to the first port  140 , and to vent pneumatic pressure from the second port  142 . In this position, pneumatic pressure can pass from the pressure source  120 , through the on-off pneumatic driver  122 , and to the first port  140  where the pneumatic pressure provides pneumatic power to the vitrectomy probe. At the same time, pneumatic pressure at the second port  142  can pass through the on-off pneumatic driver  122  to the muffler  124  where it is exhausted to the atmosphere. In the other position, the on-off pneumatic driver  122  allows pneumatic pressure to pass from the pressure source  120  to the second port  142  where the pneumatic pressure provides pneumatic power to the vitrectomy probe  112 . At the same time, pneumatic pressure at the first port  140  can vent through the on-off pneumatic driver  122  to the muffler  124  where it is exhausted to the atmosphere. The on-off pneumatic driver is configured to receive operating signals from the controller  126  as further described below. 
     In operation, pneumatic pressure is directed alternately from the source  120  to the first and second ports  140 ,  142  to operate the vitrectomy probe  112 . The on-off pneumatic driver  122  alternates between its two positions very rapidly to alternatingly provide pneumatic pressure to the first and second ports  140 ,  142 . 
     Although shown with a single pneumatic driver  122 , other embodiments include two pneumatic drivers, one associated with each of the two ports  140 ,  142 . These embodiments operate similar to the manner described, with the drivers being configured to independently receive operating signals from the controller  126 . Yet other arrangements are contemplated. 
     It is worth noting that the multiple ports on the outer cutting tube  152  may be used independently of the cutting head  174  on the inner cutting tube  154 . Likewise, the dual cutting edges on the inner cutting tube  154  may be used independently of the multiple ports on the outer cutting tube  152 . 
       FIG. 8  shows another embodiment of an inner cutting tube, referenced herein by the numeral  300 . The inner cutting tube  300  is arranged to cooperate with the outer cutting tube  152  and includes a main tube  302  and a cutting head  304  with a cutting blade having a distal cutting edge  306  and a proximal cutting edge  308 . In this embodiment, however, the connecting portion is not a centrally disposed shaft as in the embodiment of  FIG. 4 , but instead is a plurality of extending supports  310  that extend from the main tube  302  to the cutting head  304  and define a posterior cavity  312  therebetween. In use, the extending supports  310  align between the ports  168  in the outer cutting tube  152  so that the openings forming the posterior cavity  312  are aligned with the ports  168 . As such the extending supports  310  do not interfere with or block the ports  168 . 
     In one embodiment, the posterior cavity  312  is formed between the main tube and the cutting head  304  and may have an axial length equal to or greater than the ports  168  or may have an axial length less than that of the ports  168 . In one embodiment, the cutting head includes anterior cross-blades (not shown in  FIG. 8 ) as discussed above. 
     The systems, devices, and method described herein may improve surgical outcome by increasing cut rates and aspiration rates. 
     Persons of ordinary skill in the art will appreciate that the embodiments encompassed by the present disclosure are not limited to the particular exemplary embodiments described above. In that regard, although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure