The present invention relates to an insertable sleeve or tube for use in trans corneal procedures to protect the cornea and other eye layers during the procedures as well as sealing the eye from rapid outflow. The sleeve or tube is inserted into an incision and protects the incision and eye layers inside from disturbance or damage. The sleeve or tube are also self-sealing and prevent unintended outflow from the eye.
Intraocular surgery in the anterior portion of the eye has evolved over time. Initially an eye would be opened for cataract surgery with a large 10+ mm opening at the scleral corneal border then sutured closed after the procedure was complete. With the advent of a method of lens extraction using vacuum and ultrasound and flexible intraocular lenses, the incision size was reduced and the entry area moved from the scleral corneal border to the clear cornea.
Currently clear cornea is the predominant method for most procedures involving the anterior segment of an eye. In this method a blade is used to create a self-sealing incision. Though there are many small variants on the technique in general, the surgeon begins the entrance at the scleral corneal border bringing the path parallel to the surface for the initial 2-3 mm and then angling into the anterior chamber. Over time this incisional dimension is believed to give the best balance of freedom to work in the eye, control of outflow during surgery and self-sealing without need or a suture closure at the end of the procedure. The dimensions of the corneal opening can vary but a square or somewhat rectangular incision is the normal result. With a blade there is often significant variation with the length often being longer or shorter than intended. If the incision length is longer, the angle of instrumentation down to the cataract is greater and the cornea must be depressed under the incision which can lead to distortion or inability to optimally use instruments in the eye to access the cataract under the incision. If the incision length is too short, the incision may not be self-sealing, and unintentional iris extrusion during or after the procedure is possible from expulsion of water out of the incision. As the amount of stroma is less, forgiveness of the physical trauma to the stroma is greater and these short incisions are more likely to leak and give way post operatively. A suture may be needed to secure the incision in the immediate postoperative period.
The cornea is composed of a skin layer based on a tough thin layer called Bowman's. Below the Bowman's layer is a lamellar tissue known as the stroma. It is crosslinked and more adherent to itself near the surface and becomes more hydrated and less dense near the interior of the eye. The inner layer of the cornea is an important tissue based on a membrane known as Descemet's membrane. The Descemet's membrane includes cells that are pumping cells and are critical to corneal function. These cells are called endothelial cells. If these cells are injured or dislodged from their base, the cornea above them will thicken from fluid. Normal thickness of a cornea is variable but generally is 540 um centrally and 6-700 um at the corneal scleral rim where the incision is created. Without endothelial pumping, the cornea will become opaque from swelling of fluid and the thickness can double from normal. To protect these cells during cataract surgery a viscoelastic hyaluronic gel is placed into the anterior chamber that coats these cells. The significant fluid flow and ultrasound used could injure them. If the surgeon contacts the endothelial cells with an instrument the Descemet's membrane can be dislodged creating a ‘flap” of these cells which are now not attached, and the eye will thicken above. Often after completion of modern cataract extraction, a gap is seen where the inner opening of the eye has been stretched or the devices have pushed back a small section of the endothelium. If this occurs near the center of the cornea the results can be minor to major alterations of vision from the distortion created by the regional swelling. The total count of cells varies across the cornea but humans are born with 2500-3500 cells per square mm and the count may fall throughout a lifetime. When the number falls below 1000 and especially near 500 the cornea will have an excess of fluid which leads to micro cysts under the surface known as “bullous keratopathy” and corneal fogging from the water altering the architecture of the layers.
During cataract surgery, a corneal incision will have several instruments inserted through the incision to first remove a cataract and then insert an intraocular lens. The primary instrument, named a phacoemulsifier, uses ultrasound that is generated in the handle and then directed into the metal tip directionally to soften and then allow vacuum extraction of lens material. When ultrasound is required to soften the cataract a small amount of heat is generated. To modulate this the device has a silicone sleeve and water is flowing around the metal needle to equal the flow out of the eye as lens material is vacuumed out. Without this and sometimes with it heat can injure the tissue causing a mild to severe burn in the cornea. Severe burns are rare today and minor inflammation is likely more common especially in cases requiring higher need for ultrasound. The tip of the phaco instrument is metal, sharp and either straight or angled. It must pass through an incision tunnel to begin the surgery and is moved in and out to manipulate the lens and capture lens fragments. There is significant flow around the needle tip out of the eye which hydrates the tissue of the stroma and especially the less crosslinked inner cornea. This increases the risk of weakening the attachment of Descemet's membrane. The lamellar tissue of the cornea is layered and the devices sliding in and out of the eye separate the layers from frictional and hydrational effects. Following lens removal, another instrument is introduced to remove the softer cells that surround the cataract and that are adherent to the lens capsule and then are reintroduced after the IOL is placed. To remove the “cortex” or the cells adherent to the delicate lens capsule the tip has a smaller opening and it is angled with stripping motion to “peel” the cells off the capsule. There is more stretching and incisional stress in this step of the procedure as the tip is angled to reach the area adjacent and underneath the incision. With both of these instruments the sleeve is in constant contact with the endothelial edge of the incision sliding in and out of the eye, and as it is narrower than the phaco instrument a significant amount of backflow will pass along the outside as pressure builds in the eye. It is often after withdrawal of this device that iris tissue will flow with it out through the incision. Finally, a tube containing the intraocular lens (IOL) is inserted into the incision to push the IOL into the eye. The width of this tube is variable by the style, volume and flexibility of the implant. Larger lenses are thicker and will require a larger tube. This step is often the incision size limiting point. The current variability is 2.2 mm to 3.0 mm on average. 2.4 mm to 2.6 mm is required to complete most cataract surgery. As these instruments are round it should be noted that the diameter of the inserted instruments is not the incisional size. The tube width or diameter at 2.4 incision cannot be more than 1.5 mm. This tip is angled through the incision which is often just large enough to pass it. The tube is made of a distensible plastic. It can catch the lip of the inner part of the incision and strips back a small area of the Descemet's membrane and endothelial cells. Though it has not been studied it is likely a point where this particular incisional trauma occurs. To balance the needs of lens insertion, minimal back flow during surgery and self-sealing at the end of the case have been the guiding issues surrounding incision size and care. Indeed, larger incisions would likely be more commonly used if the incision was secure during and after surgery.
A cataract surgery typically also uses a second smaller incision of approximately 1 to 1.5 mm that is made laterally to the primary incision. This incision receives the most amount of instrumentation. It is often referred to as the “sideport” incision. This second incision is then used to push fluids and gels into the eye, manipulate the lens using a hooked instrument to “chop” the cataract, position the IOL and experience the largest amount of out flow during the surgery as the primary incision is more occluded by larger instruments and their sleeves. Any need to work laterally into the eye uses this incision. As the surgeon angles thin instruments through this opening the internal pressure of the eye is relieved and water can be observed flowing rapidly. If 150 cc of balanced saline solution is required in a cataract surgery ⅓ to ½ of this will flow from this incision. Again, its inner edge often remains gaped after the procedure though rarely recognized due to its small size. It often has leakage at the conclusion of the surgery from stretching and manipulation. The maintenance of a stable anterior posterior environment is essential in cataract surgery as the vacuuming tips are working within less than a mm of the lens capsule. If this capsule is inadvertently torn the vitreous held back by the capsule will come forward and lens particles can fall into the back of the eye. The intraocular lens may not be well centered and it generally cannot be placed into its normal position inside the capsular bag as it would not be supported. The lens power must be reduced and the lens is placed on top of the capsule if possible. These patients are at higher risk of post op issues like cystoid macular edema and endophthalmitis. Maintaining a stable anterior chamber is about reducing sudden motion which is normally from a sudden reduction in the internal pressure as water ejects from an incision. Sealing these incisions therefore stabilizes the eye, and leads to a reduction in the total amount of fluid needed to complete the cataract.
At the end of a procedure water is injected into the cornea to expand the tissue laterally and tighten the pocket to reduce fluid egress and ingress post operatively. The more the incision has been manipulated, stretched and stripped, the poorer this is likely to work in the minutes to hours after the patient is discharged. The injected fluid into the tissue resolves within minutes of the patient leaving the OR and if wound leakage is more likely in an eye that has had a large amount of instrumentation. There is evidence that in longer surgeries and surgeries where complication led to more instrumentation that a higher rate of endophthalmitis can occur. This is a rare but sight threatening infection inside the eye. These wounds can be seen years later as with haze and scarring from instrumentation trauma.
Careful examination of these incisions will demonstrate swelling and endothelial cell loss under and around these incisions. A gap or tear in the Descemet's membrane and the endothelial cells adherent to it is a ubiquitous finding. In many corneas the area can be observed to have thickening and fogginess associated with endothelial dysfunction. The longer term sequelae are less common. A persistent area of edema or thickening creates a foreign body or “dry eye” sensation. The thickening of the cornea may create a light or “fog” visual effect from the cornea being swollen laterally.
There are also many reasons for the iris or colored part of the eye to be traumatized during cataract surgery. The common cause of injury is from this thin friable tissue flowing back out of the eye through the incision. This is known as iris extrusion. The pressure in the eye is elevated by fluid flowing into the eye and on removal of an instrument a rush of water carries the iris through the incision. The surgeon must decrease the pressure inside the eye and carefully move the iris back into the eye. When this happens, the pigment covering this tissue is dislodged and light can now pass through the tissue leading to glare and secondary images. This is made worse when the patient feels pain as this tissue is sensitive and when it is squeezed out of the incision it induces further squeezing. Using viscoelastic and patience, the surgeon can often regain control and finish the case. Unfortunately, the iris is now injured. The pigment is stripped and the pupil may not return to a normal round shape. A short incision and can occur in any case even without the pathologies described. And as the short incision is less effective at sealing the eye, the likelihood of extrusion is increased. As the surgeon is aware of this, currently there is no effective method to assure that extrusion will not occur. A glare effect from light passing through the damaged area, a distorted pupil or both is the result of this uncontrolled flow out of the incision. The dependence on the random hand-made incision is a weakness of modern cataract surgery for this reason alone. Backflow out of the eye is a random and sight threatening event that occurs regularly with current technique and tools.
A thin iris is often light in color or has been weakened by drugs. A condition known as IFIS or Intraoperative Floppy Iris Syndrome is common and can be the result of the use of alpha1-antagonists for Benign Prostatic Hypertrophy as well as a myriad of other conditions. If a pupil is weak and thin, it can obscure visibility adequate for cataract extraction and require the use of hooks to capture the iris or a device extruded into the eye like a Malyugin ring. Often the dilation is adequate, but the risk of iris extrusion is so high that the ring is used to control the iris from extruding.
The insertion of an IOL is often the moment when the most stress is placed on the incision as this is the widest instrument used. It is likely that the stripping of the endothelium is occurring often in this step as the surgeon pushes against resistance to stretch the incision to get the nozzle of the inserter beyond the inner lip of the cornea.
It is an object of the present invention to overcome or reduce the challenges of intraocular eye surgery as explained above. The intent of these devices is to protect the cornea from instrumentation, to seal the eye to decrease uncontrolled outflow and to act as a conduit into the eye for treatments and monitoring.
Simple and inexpensive devices are described herein for protecting the corneal tissue from instrumentation and to seal the eye from uncontrolled outflow. As it is a sealed conduit into the eye other uses may be applied. These devices include sleeves or tubes that may be inserted into the eye during surgery. The devices provide a passage from an eye incision into the portion of the eye where a procedure is performed. The sleeve protects all of the various components of the eye that must be passed through by instruments during a procedure. A proximal end of the sleeve is anchored to the corneal incision to prevent the sleeve from being pushed into the eye. The distal end of the sleeve inside the eye is supported so that the sleeve is stable with instrumentation during a procedure. The device seals backflow as the sleeve is stretched against itself or a plate. The tube has a collapsible valve to prevent backflow.
In one example, a protector for a trans-corneal incision comprises a tubular sleeve that defines a width and length, wherein the sleeve has a proximal end and a distal end. The proximal end includes wings that extend outwardly from the width of the sleeve, and the proximal end is adapted to engage the perimeter of an ocular incision and the wings extend outside of the perimeter of the ocular incision to prevent the sleeve from being pushed into an eye. Wherein the distal end is adapted to extend into intraocular eye space in the direction of the length of the membrane. The tubular sleeve may be a flexible membrane. The protector may further comprise a frame that is connected to the sleeve and holds the sleeve in an expanded position to secure the sleeve in an eye. The tubular sleeve membrane may be multilayered and comprise a sealed bladder that is open to an exterior valve. The tubular sleeve membrane is expandable by injecting air or fluid into the sealed bladder in the membrane and through the valve. The sleeve may further comprise a plurality of small spikes that project outwardly from the outside of the sleeve for securement of the sleeve in an intraocular incision. In another example, the tubular sleeve may comprise a rigid tube. The rigid tube may have an expandable bladder mounted around an outside portion of the rigid tube. The sleeve may have a sealed inner layer of fluid therein in order to moderate heat transfer through the membrane wall. The sleeve may be colored or clear. The sleeve may be coated on its outside surface with an antibiotic material or an anti-inflammatory material. The sleeve may further comprise an expandable spring to actuate the expansion of the sleeve. The frame may comprise two arms connected by an arch, and the arch having raised elements on its posterior surface to secure to the flexible membrane.
The device described herein is engineered to protect corneal tissue during intraoperative procedures. The various design elements serve to seal the incision from backflow. In one example, a sleeve is stretched over the frame to create a seal when closed and allow passage of instrument of variable size. The sleeve is described herein in terms of two examples. Similar protector devices may be designed that are also covered by this disclosure. The first example is a polymer or fabric sleeve that expands and is secured into an incision that will then be the passage for all instruments entering the eye. It will also seal the eye from backflow of liquids and tissue out of the passageway. The second example is a relatively rigid tube with an external bladder that is expandable into the incision to secure it from movement and acts as a valve for passage into the eye without backflow.
The first example of a sleeve described herein is used in intraocular procedures to pass from outside the eye to inside the eye encompassing the width and length of an incision made to access the anterior chamber. The protector device includes a sleeve that enables the use of tools used in an intraocular procedure to pass into and out of the intraocular space without coming into direct contact with the tissue along its length. It effectively seals the eye eliminating inadvertent backflow and stabilizing the intraocular environment from collapse because it is stretched apart by a number of described devices. The sleeve is secured to the eye incision by several methods both externally and internally. The protector sleeve may be composed of elastic material that allows it to be expanded into the exact fit of the incision while sealing around instruments as they are inserted into the eye. These materials include latex, rubber, alginate polyacrylamide, a hydrogel, polymers, neoprene, fabric material like spandex, nitrile rubber or synthetic rubber, polyvinyl chloride and other known elastic materials. The sleeve is open externally by a securing method to allow for easy access. The distal end of the sleeve inside the eye will be stretched closed when an instrument is not passing through it. The sleeve effectively acts as an extension of the incision deep into the eye as it seals similar to the “pocket” like incision.
The first protector device, an example of which is shown in
In another example of a protector 111, as shown in
The expansion arms 30 (
One method of expansion is a spreading of the sleeve 12 and 130 by using a flexible plastic to form the frame 14 and 110 that is molded and biased toward expansion and that is squeezed together by a surgeon for insertion and, when released, expands the sleeve into the width of the incision. The arch 34 and 114 is the expansive force holding the protector 10 and 111 in place at the incision. The distal end 20 of the sleeve 12 is wider than the proximal end 22 of the sleeve. Between the arms 30 and 112 of the protector 10 and 111 past the incision, a flat crossmember 36 and 116 with the V shape made of the same flexible plastic as the rest of the frame 14 and 110 will add further structure and expansive force to the device. The crossmember 36 and 116 may also assist in securing in place a patient's iris by bearing against it during a procedure. This crossmember 36 and 116 will have a thin extension which is a landing pad for instruments to guild them into the eye over the top of the sleeve. The sleeve 12 and 132 is designed to remain in place against movement of medical instruments through the sleeve both in and out during a procedure. The sleeve 12 and 132 can elongate as it passes over the external arch and folded back under the arch. As shown, a crown of pegs 120 or spikes may be added to secure the flap of sleeve 12 and 132 draping over the arch 34 and 114. One example of a sleeve 132 may have lateral holes 134 to be captured by the pegs 118 in the first 1-2 mm of the internal arms 112. No holes are necessary for this additional securing point of the sleeve. Also, the crossmember may not be necessary for securing the protector 10 and 111.
The size of the arch 34 and 114 would vary by incisional size. Before insertion the width may be 3 mm or greater for a primary incision version. Inserted the width across the arch 34 and 114 would be whatever the incision size determined. A common result would be 2.4-2.6 mm. This width would allow for passage of many instruments including an intraocular lens inserter.
Another example of a protector 280 is shown in
The protector may have multiple sizes intended for different-sized incisions as required in different procedures. The dimension of the sleeve portion of a protector may be 1.0 mm to any width and length required to encompass the width and depth of an incision. In larger forms, the protector may have width and length dimensions of from about 3 mm to 5.5 mm, or alternatively about 2.6 to 3.5 mm. In smaller versions of the device, the width and length dimensions may be from about 1 mm to 2.5 mm, or alternatively about 1.5 mm to 2.5 mm. In all examples, a sleeve may be sized so that the expansion of the sleeve after insertion into an eye can create a watertight seal to the eye for infusion or extraction of fluid into and out of the eye.
Surgical glove materials are a good material to form a sleeve because of their elasticity and resistance to tearing. An arch or the other mechanisms for expansion described will stretch the sleeve portion to create the seal and protection of the tissues in the passage into the eye. The internal, distal part of the sleeve expands out further than the external, proximal portion of the sleeve adding additional sealing and reducing lateral locking of motion of the instruments working in the eye. The internal crossmember will add additional stretch internally to aid in creating a seal and will also push the iris down under the incision. This further reduces the likelihood of expulsion of iris out of the incision.
As shown in
The sleeve can be lubricated with viscoelastic. As the sleeve will be used for thrusting instruments into the eye to reduce friction inside the sleeve may aid in maintaining the sleeve and giving free movement to the instruments being used through it. Some materials like silicone become slippery when wet, so no additional lubrication may be needed. On the other hand, using a small amount of hyaluronate would facilitate smooth movement. This substance is used routinely at the beginning of cataract surgery to fill the eye so a thin line of it left inside the sleeve would aid in passing instruments during the procedure.
Examples of the use of a protector such as protector 10 are shown in
A second general example of a protector is now described in
Surrounding this tube is a thin “bladder” with a connecting tube and one-way valve. When the tube is inserted in an eye, the bladder is then filled with saline or hydrogel or air to expand and seal the tube into the incision. The outside of the bladder may have ridges, barbs, spike like projections or other texture shapes to reduce slippage. The expansion of the wall of the membrane would be accomplished using a one-way valve and a cannula to fill and remove filler to the wall of the device. The bladder surrounding the tube could be thin and add minimal width to the incisional width. Not inflated, the bladder may add 0.1 mm. The working passage tube must be stiff enough to resist the expansion of the bladder in the area passing through the cornea. The inner aspect must be flexible to allow the collapse of the tip or the movement of the valve leaves. As incisions are often variable in size the expansion of the bladder would be large enough to encompass a range of incision sizes and the tube portion would be the same for every case. The tube may be wedged shaped to allow for it to secure itself with minimal to no bladder inflation. The system could be used for the main incision and would encompass the size of the “phaco” probe and the IOL tube, in the example of a cataract procedure. Externally, the inner stiff tube will extend laterally to create wings to give support and resist the device being pushed into the eye and when held the device pulling out of the eye. Alternatively, the inflation tube may be crimped into a slit in the wing portion of the device. These types of protectors can be trocar systems. In this iteration, the tip of the trocar for insertion is a sharp cutting shape to allow the tube to be inserted through the cornea. Once inserted the cutting sleeve is removed and the expansion bladder is employed
The material used will be polyamide, poly methyl methacrylate, natural rubber as well as numerous specialty materials like Poron or Neoprene and EDPM. The optimal expansion and resistance to tearing will dictate the ideal material. The bladder system can use latex, rubber, or other expansile materials with surface scaling or pointed or rough elements to reduce slippage. A fabric material can be molded or glued to the surface of the bladder that could allow for the roughed elements to be pushed into the tissue by bladder expansion. The external aspect of the tube will be secured by a ring with two side supports extending on either side of the tunnel device. The inflation valve may be attached to these elements to keep it out of the way of the tunnel area. Alternatively, a slit may be used to crimp the inflation tube eliminating the need for a valve or being used in addition to the valve.
The inner lip of the device will collapse when instruments are removed from the eye. The inner lip may have a tongue and groove shape as necessary to create a watertight seal. The stretching of the sleeve itself will resist back flow of water. To enhance this effect however an enhanced edge that allows one side to fold into the other could further increase the resistance of outflow.
The sleeve in all of the foregoing examples may be colored. As visibility through the sleeve tunnel may be helpful in working under the incision, a clear material or minimally opaque or colored is preferred, but as the sleeve and tube are not in the surgical plane they will not block the view in the working area. As the sleeve may be difficult to see through the cornea in the eye and surgeons may wish to monitor that it is in place and functioning well a slight tint would aid in observing any defects as necessary. The bladder filler could be given a color dye as well to aid in visibility and to show its existence and volume.
In another example, the sleeve such as sleeve 12 or 132 may be coated with an antibiotic coating. Alternatively, a sleeve such as sleeve 12 or 132 may be coated with an anti-inflammatory medicine. In each case, the coating is not separately shown in the figures, except that it is coated onto the outside surface of those sleeves. In this manner, the coating may prevent or reduce the chance of swelling or infection after a procedure.
To get a second instrument in the eye in most procedures, a smaller incision of 1.0 mm to 1.5 mm is made about 90 degrees away from the primary incision. The smaller 1-2 mm protector used in a side port may, in some examples, have an inflatable sleeve to secure an infusion line or a pressure monitor. Placing the protector and then inflating it would secure the protector and surgical devices extending there through to the cornea. As the protector provides a sealed access to the anterior chamber in the eye, it could be used to monitor, sample, control and medicate the eye. This can be done through the smaller version inserted through the side port. A port could then be used to infuse and sample the anterior chamber. In cases of uncontrolled IOP it could act as a temporary shunt. In a case of endothelial graft air or gas could be infused. In a case of infection, the anterior chamber could be sampled and infused with antibiotics. In a case of hypotony or low pressure an infusion to maintain adequate IOP could be considered. In normal eye surgery, all of these methods would assist in providing a data source and a method for controlling the infusion of meds which could include dilation meds. The device could be used with a Trocar-like internal blade to place the tube and then be secured by the bladder inflation and the slide resistant elements on the side of the tube.
A hard plastic or soft external valve can be used for this device. The valve in this case would be enclosed in the external piece. The valve could be a hinged system with a plastic or metal valve. A ball valve that is displaced by insertion of a tool through the tube. A collapsible material like rubber, sponge or other elastic materials could seal tube until driven open by an inserting instrument.
This protector may be designed to inflate within the incision to provide a sealed incision while allowing access to a central passage for infusion of fluid into the eye or extraction of fluid out of the eye. The device could use the central tube to place a probe into the eye for exact measurement of intraocular pressure in real time. The water pressure expressed out of the tube could be measured with an external manometer. The IOP could be adjusted with feedback to an infusion pump. This could be used intraoperatively to place an implant without using visco elastic, to determine that the IOP is normal and that the wounds are watertight at the conclusion of the surgery. They could be used to maintain a normal pressure in a case of uncontrolled IOP crisis until another intervention could be used. The same protector could be placed through the sclera to measure the intravitreal pressure.
Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification. It is intended that the specification and figures be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
This application claims the benefit of U.S. Provisional Patent Application No. 62/841,493, filed May 1, 2019, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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62841493 | May 2019 | US |