MXPA97001540A - Grooved needle for emulsification of f - Google Patents

Abstract

A phaco-emulsification needle provided for use with a plastic or elastomeric sleeve, the needle having a portion of a middle region defining a plurality of outwardly extending projections that form longitudinally oriented grooves that provide appropriate irrigating flow rates to the anterior chamber of the eye in even when the entry cut compresses the sleeve against the outer surface of the needle, thus reducing the risk of collapse of the anterior chamber due to inadequate irrigating flow and reducing the risk of excessive heat transfer at the cut of enters

Description

The present invention relates generally to needles for phacoemulsification and more particularly to needles that provide better irrigation and which reduce the risk of corneal or scleral lesions in the tissues. BACKGROUND OF THE INVENTION A disease known as cataracts, in which the lens of the eye is opaque, is common and can lead to blindness. It has become common practice to relieve this condition by surgically removing the lens affected by the cataract and replacing it with an artificial intraocular lens. The lens affected by the cataract is usually removed by manual extraction or phacoemulsification.

The manual extraction requires aspiration of the lens nucleus through a cut of a length of approximately 12 mm. The technique known as phacoemulsification described for example in US Pat. No. 3,589,363 allows the removal of a lens affected by cataracts through a much smaller incision of approximately 2.5-4 mm, for example from 3.2 mm. This is accomplished using high frequency ultrasonic energy typically at a frequency of 40 kHz, which is transmitted by a phacoemulsification needle to fragment or emulsify the lens core affected by cataracts.

Once fragmented or emulsified, the nuclear material is aspirated through a phaco-emulsification needle channel. During the aspiration of the fragmented core, a simultaneous liquid flow is provided in the eye around the needle through a soft plastic or elastomeric sleeve which is arranged concentrically on the needle to form an annular space. This fluid flow in the eye is essential to prevent collapse of the anterior chamber of the eye when the emulsified fragmented core is aspirated through the phacoemulsification needle. Also, the liquid that enters serves to cool the needle, which reduces the heat generated by the ultrasonic vibration of the needle. If, instead, this heat were allowed to pass through the cut-in of the eye, thermal damage to the corneal or scleral tissues could occur. One of the difficulties encountered in the practice of the phaco-emulsification technique is the need to maintain tightness with minimal leakage between the cut-in of the eye and the sleeve or sheath surrounding the phaco-emulsification needle. If the entry cut is too small, the sleeve could be compressed against the needle, thereby restricting the flow of irrigation to the anterior chamber and allowing the transmission of frictional heat to the cut.

Alternatively, if the cut is too large to avoid compression of the jacket, unacceptably high leakage around the jacket could occur eg at 25 cc / minute. The liquid that is lost through the leak must be replaced by liquid that enters through an annular space between the plastic sleeve and the needle, which reduces the margin of safety necessary to maintain a constant volume in the anterior chamber. Accordingly, in order to avoid collapse of the anterior chamber, the flow of liquid entering through the annular space should never be less than the total liquid flow exiting through the phacoemulsification channel and through the phacoemulsification channels. leaks around the shirt. In response to these problems, a variety of techniques have been developed that attempt to reduce leaks from the cut by improving the tightness between the cut and the jacket, and at the same time avoiding the transmission of heat to the cut. In a first technique a rigid plastic jacket constructed from a material such as a polysulfone is used instead of a softer silicone material, since the polysulfone resists the compression caused by the cut. Another technique, which has been described in US Pat. No. 5,282,786, incorporates a plastic or rigid metal shirt that is disposed on the outer circumference of a softer silicone jacket so that the rigid plastic makes contact with the inlet of the cut. These techniques however have the disadvantage that they increase the distortion of the wound and tend to extend the cut during the procedure, which increases the escape. A second technique described for example in U.S. Patent Nos. 5,286,256 and 5,354,265, employs a rigid metal or plastic intermediate sleeve that is inserted into the annular space between the conventional soft outer silicone sleeve and the phaco needle. emulsification. The rigid intermediate jacket is allowed to "float" on the outside of the phacoemulsification needle, and said needle may have a reduced external diameter in a medial region to limit the longitudinal path of the intermediate jacket. The reduced middle region of the needle allows a small incision to be made while maintaining a flow of fluid around the phacoemulsification needle. However, it is believed that such benefits are more than compensated for by the increase in the overall diameter of the apparatus to accommodate the intermediate jacket and by the overall reduction of the area of the cross-sectional irrigation flow caused by the presence of the intermediate jacket. A third technique which attempts to solve the problems of fluid escape by inlet cutting and heat transmission has been described in US Patents Nos. 4,634,420, 4,643,717, 4,808,154 and 5,242,385. Each of the shirts described in these patents includes a plurality of inwardly extending projections serving to reinforce the sleeve against compression, in order to limit the contact between the sleeve and the phaco-emulsification needle, and Provide flow channels in case the sleeve is compressed against the needle. All these designs share the common drawback that the projections increase the stiffness of the sleeve, which causes the risk of transmitting more frictional heat to the input cut. In addition, all these designs require a larger entry cut to accommodate the added dimension of the projections. Further, if protrusion of silicone or other elastomeric material or soft plastic is formed, it is likely that the compressive loads transmitted to said jackets from the inlet cut compress the projections to a degree where even unacceptably low flow rates may occur. In view of the foregoing, it would be convenient to have a phaco-emulsification needle that overcomes the drawbacks of previously known needle and sleeve systems by allowing the use of a smaller size cut, and that would reduce the risk of restriction of the Fluid flow around the needle. It would further be convenient to provide a phaco-emulsification needle that will provide a reduced contact area between the needle and the sleeve, thereby reducing the transmission of heat to the adjacent tissue, with an attendant reduction in the risk of tissue injury. It would also be convenient to provide a phaco-emulsification needle that ensures an adequate flow of irrigation and even in those cases in which the shirt is compressed against the outside of the needle. It would also be additionally convenient to have a device that could be used with a phaco-emulsification needle to improve fluid flow and reduce heat transmission in those cases in which the jacket is subjected to high compression loads in the input cut . SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a phaco-emulsification needle that overcomes the drawbacks of previously known needle and sleeve systems, allowing the use of a small size cut, and that reduced the risk of restricting fluid flow around the needle. It is another object of the invention to provide a phaco-emulsification needle that provides a reduced contact area between the needle and the jacket thus reducing the transmission of heat to adjacent tissue., with the concomitant reduction of the risk of tissue injuries. It is yet another object of the present invention to provide a phaco-emulsification needle that ensures an adequate flow of irrigation even in those cases in which the sleeve is compressed against the outside of the needle.

It is yet another object of this invention to provide a device that is used with a phacoemulsification needle that improves fluid flow that improves fluid flow and reduces heat transmission in those cases in which the jacket is subjected to high Compressive loads at the entrance cut. These and other objects of the invention are achieved in accordance with the principles of the present invention by providing a phacoemulsification needle comprising a cannula having an axially extending channel for extracting material from an eye, and at least in the middle region of the needle, one or more channels or axially extending grooves disposed externally to the channel, for supplying fluid to the eye during aspiration. With the phaco-emulsification needle of the present invention, even when a soft plastic or elastomeric sleeve is pressed against the needle, the channels or flutes allow a continuous flow of fluid and at the same time reduce the contact area between the sleeve and the sleeve. needle, which reduces the risk of thermal injuries at the entrance of the wound. In a second embodiment of the present invention, a jacket is provided having a plurality of projections extending outward, and which may be disposed on the outer surface of a phacoemulsification needle. The sleeve of the second embodiment may be disposed in a middle region of reduced circumference of the needle to provide benefits similar to those of the first embodiment described above. Other features of the invention, its nature and various advantages will become more apparent in the accompanying drawings and in the following detailed description of the preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal section of the previously known phacoemulsification needle; Figure 2 is a perspective view of a phacoemulsification needle constructed in accordance with the present invention; Figure 2b is a section along line 2B-2B of the phacoemulsification needle of Figure 2A showing the needle disposed within a sleeve; Figure 3 is an enlarged cross-section according to line 3-3 of Figure 2A; Figure 4 is an enlarged cross-section according to line 4-4 of Figure 2A; Figures 5A and 5B are respectively a perspective view and a cross section of an alternative embodiment of the needle of Figure 2A; Figure 6 is a perspective view of another alternative embodiment of the phacoemulsification needle of Figure 2A; Figures 7A to 7D are alternative designs for the tip 18 of the phacoemulsification needles of the present invention; Figure 8A is a perspective view of a liner with projections or ribs and a phacoemulsification needle according to another alternative embodiment of the present invention; Fig. 8B is a cross-section according to line 8B-8B of the phacoemulsification needle of Fig. 8A showing the needle disposed within a sleeve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to Figure 1, a previously known phaco-emulsification needle 10 is shown comprising a hub or core 12 and a hollow cannula 14 extending from the hub 12. A threaded portion 16 extends from the hub 12 in the proximal portion of the cannula 14 as is conventional. The cannula 14 ends at the tip 18 of the distal end (ie remote from the hub 12). The needle 10 contains a central channel 13 extending axially through which material can be sucked from an eye using techniques. known as those described above. The sleeve 17, which typically comprises a soft silicone material, is disposed over the needle 10 to form an annular space 19 through which liquid can be supplied to the anterior chamber of the eye during aspiration. As further described in the foregoing, the jacket 17 may be compressed by the eye, and in particular, the portion surrounding the entrance of the cut, in order to reduce the flow of liquid to an unacceptable degree. With reference to Figures 2A and 2B, a phacoemulsification needle 20 constructed in accordance with the present invention is described, in which like numbers indicate equal parts. As will be understood by those skilled in the art, Figures 2A and 2B are not drawn to scale, but are simply provided for illustrative purposes. The needle 20 that is typically constructed with titanium comprises a hub 12, a channel 13, a threaded portion 16, a tip 18 and a tubular portion 21 located in the middle region 25 between the tip 18 and the hub 12. Also with reference to 3, the tubular portion 21 illustratively comprises a hollow cylindrical member 22 of reduced circumference having a plurality of equidistant protrusions or ribs 24 extending radially outwardly from the outer surface of the member 22. As shown in Figure 2B if the projection 24 of the middle region 25 is alternately viewed from the perspective of the outer diameter of adjacent or remote adjacent regions, the interstices between the adjacent projections 24 appear as channels or grooves 30 oriented longitudinally on the outer surface of the needle 10. The projections 24 on the cylindrical member 22 of reduced circumference can have their external surfaces flush with the outer surface of the needle 20 in the proximal and remote regions of the middle region 25 (such as in Fig. 2B), or they may extend slightly below or beyond the outer surface of the needle 20 in the adjacent adjacent regions and away. To accommodate the projections 24 (and therefore the grooves 30), the channel 13 can have a reduced diameter in the central region 25, as can be seen by comparing Figures 3 and 4. The projections 24 and the circumferential cylindrical member 22 reduced may be arranged only in the middle or middle region of the needle 20, which is the region that is typically subject to the compressive load of the tissue surrounding the entry cut, or which may alternatively extend along the outer surface of the needle 20 to the tip 18. Arranged around and spaced apart from the tubular portion 21 is the jacket 17, which may be formed of elastomeric material or soft plastic, for example silicone. When the tubular jacket 17 is subjected to compression and comes into contact with the needle 20, the adjacent projections 24 together with the intermediate portion of the cylindrical member 22 of reduced circumference, and the external surface of the jacket 17, form channels or grooves 30 that They extend along the needle 20. Therefore, if the needle 20 is subjected to pressure along its middle region during a procedure for the removal of the lens affected by cataracts, the reduction of the cross-sectional areas of the channels 30, is inhibited by the presence of the projections 24. The flow of liquid through the jacket 17 by means of the channels 30 can therefore be maintained at a satisfactory level to remove the liquid extracted by aspiration in the anterior chamber Of the eye. Furthermore, special external jackets are not necessary to ensure adequate irrigation using the needle 20. Therefore, the tightness between the jacket 17 and the inlet cut can be achieved by the previously known sleeve 17 as described in Figure 1. , while maintaining the required cutting size within the range of 2.5-3.2 mm. The tubular portion 21 may have a variety of cross-sectional shapes, including circular and elliptical configurations, and may have an outer circumference less than, equal to, or greater than the circumference of the adjacent portions proximal and remote from the needle 20.

In addition, the central channel 13 of the needle 20 may have a single diameter over its total length or it may be formed by a reduced diameter in the middle region of the tubular portion 21. Likewise, the projections 24 (and the ridges 30) may be in greater or lesser amounts than those shown in the accompanying drawings, and may form portions of the outer circumference of the central portion 25 larger or smaller than those shown in the accompanying drawings, which must consider only examples. In addition, it is not necessary that the projections 24 be spaced equidistantly around the circumference of the tubular portion 24, but may be concentrated in the upper and lower portions of the needle 20, which are likely to be experienced by the compressive loads. With reference to Figures 5 and 6, alternative embodiments of the phaco-emulsification needle of the present invention are shown, in which again the same numbers refer to equal parts. In the figure. 5A the needle 20 'has projections 24 oriented longitudinally, spirally around the circumference of the cylindrical member 22, thereby creating spiral-shaped channels. As illustrated in FIG. 5B the projections 24 can be formed or machined to create hollow channels 26 communicating with the channel 13, thereby increasing the flow area through the middle portion of the needle. Of course, as will be understood by those skilled in the art, the protrusions or ribs 24 of any of the embodiments of Figures 2-5 may advantageously include hollow channels 26. In addition, the channels may be disposed either in the middle portion of the needle , or they can extend over the entire length of the total internal surface of the needle. In Figure 6, the projections 24 of the needle 20 are formed as individual diamond-shaped islands longitudinally oriented and extending outwardly from the outer circumference of the cylindrical member 22, for example by cutting helical grooves of opposite direction on the needle of the needle. As will be understood by those skilled in the art, splines 30 may be arranged on a needle 20 'and 20"by rotating the needle as grooves 30 are formed. In a preferred embodiment of the needle of FIGS. 6, the projections 24 and the cylindrical member 22 can be formed by machining a single piece of titanium to give it the desired shape. Alternatively, a phacoemulsification needle according to the present invention can be formed from stainless steel, a suitably resistant plastic compound or a combination thereof. Likewise, the projections 24 can be formed in a variety of configurations that can be easily manufactured, for example in the form of circumferential channels with longitudinally oriented communications, or can even have cylindrical shapes of the cube type. With reference to FIGS. 7A to 7B, alternative designs of the tip 18 of the needle 20 are illustrated. FIG. 7A shows the channel 13 in the portion remote from the needle 20 that expands to the tip 18 in the form of a cannula; Figure 7B shows the channel 13 having a curved configuration of the type of a horn as it expands to the tip 18. The figures. 7C and 7D illustrate alternative embodiments in which the channel 13 expands to the tip 18 through a series of multi-camera stages 13A-13B and 13A-13C. The above channel and tip configurations can be advantageously used, with any of the phacoemulsification needles of the present invention. Referring now to FIGS. 8A and 8B, another alternative embodiment of the phacoemulsification needle of the present invention is described, which is the needle 40, in which again identical numbers denote identical parts. The needle 40 includes a portion 21 of reduced circumference in the middle region 25. The projections or ribs 24 and the cylindrical member 22 form a separate insert 41 which is disposed in the reduced circumference portion of the needle 40. An insert 41 may be formed. with an elastomeric material or soft plastic, for example silicone, and is preferably dimensioned so as to form the space 42 between the inner surface of the cylindrical member 22 and the outer surface of the reduced circumference portion 21. The cylindrical member 22 may also include a longitudinal slit that allows the cylindrical member 22 to be easily installed on a reduced circumference portion 21. Alternatively, the cylindrical member 22 may be sized to holster a conventional phaco-emulsification needle 10 such as It is shown in Figure 1 but then it may be necessary to use a larger shirt 17 and a larger inlet cut. When installed either in the reduced circumference portion 21 of the needle 40 or in the standard needle 10, the insert 41 is expected to provide many of the advantages described above with respect to the needle embodiments of the figures , 2-6. The applicant has carried out some experiments using a silicone "eyes" model used in phaco-emulsification training workshops, in which the silicone "cornea" can be interchanged. In particular, the Applicant used a Master 10,000 series emulsification system provided by Alcon Surgical, Fort Orth, Texas, to compare the cooling capacity behavior of a needle constructed in accordance with the embodiment of Figure 2 with a needle. phaco-emulsification Master standard. The experiments were carried out with an energy setting of 70 in the Master system, a vacuum of 100 mmHg, a vessel with a height of 65 cm, an irrigation flow rate of 20 cc / min and an initial irrigation temperature of 25.6ßC. By varying the size of the incision from 2.75 mm to 4.1 mm in the silicone cornea (obtained using a keratome), the temperature of the liner at the compression point caused by the incision was measured with a thermocouple for both the standard needle as for the needle of figure 2 after 15 seconds of operation. The results are shown in Table 1.

Temperatra in BC of the shirt Size of the incisionfmm ^ Needle standard Needle of the 2.75"53 37 3.00 50 32 3.25 47 32 3.50 44 30 4.10 33 28 As can be seen in Table 1, the jacket temperature was lower for the needle of Figure 2 in all incision sizes and always remained below 40ßC. In contrast, using the standard tip, the jacket reached temperature levels exceeding fifty degrees - a temperature below which it could be assumed that thermal injury and collagen shrinkage would occur. The applicant carried out similar experiments in which the size of the incision was maintained at 3.00 mm and the flow rate varied from 20 to 35 cc / min. Although neither the behavior of the standard needle nor that of the needle of Figure 2 varied greatly by changing the rate of irrigation flow, the temperature of the sleeve for the needle of Figure 2 was approximately 20BC less than for the standard needle. . In a third series of experiments, the applicant maintained the size of the incision at 3.00 mm, maintained the constant flow rate at 20 cc / min, and varied the height of the irrigating vessel from 65 to 75 cm. This also did not produce too much effect on the jacket temperature for any of the needles, but again the temperature of the needle sleeve of Figure 2 was approximately 20 ° C. less than for the standard needle. While the preferred illustrative embodiments of the present invention have been described above, it will be obvious to one skilled in the art that various changes and modifications may be made thereto if depart from the invention and in the appended claims cover all changes and modifications that fall within the scope of the invention.

Claims (35)

1. CLAIMS 1. A phacoemulsification needle comprising: a cannula having a proximal end, and a remote end, a middle region, a first circumference, and a longitudinal channel extending through the cannula from the proximal end to the far end; a hub that is disposed at the proximal end, the longitudinal channel extending through the hub; and a tip disposed at the distal end, where the middle region has a second circumference and a plurality of longitudinally extending projections extending outward, disposed from the second circumference.
2. 2. The phacoemulsification needle defined in claim 1 wherein the second circumference is different from the first circumference.
3. 3. The phacoemulsification needle defined in claim 2, wherein the second circumference is smaller than the first circumference.
4. 4. The phacoemulsification needle defined in claim 3 in which the projections have an external diameter, and the external diameter of the projections is flush with the first circumference.
5. The phacoemulsification needle defined in claim 1, wherein the longitudinal channel has a first cross-sectional area and, in the middle region, the channel has a second cross-sectional area that is smaller than the first cross sectional area
6. 6. The phacoemulsification needle defined in claim 1, wherein the projections extending outward form a plurality of ribs.
7. 7. The phacoemulsification needle defined in claim 6, wherein the ribs are hollow.
8. 8. The phacoemulsification needle defined in claim 6, wherein the plurality of ribs are mutually parallel.
9. 9. The phacoemulsification needle defined in claim 8, wherein the plurality of ribs form a spiral around the second circumference.
10. 10. The phacoemulsification needle defined in claim 6, wherein the plurality of ribs is spaced equidistantly around the second circumference.
11. 11. The. phaco-emulsification needle defined in claim 6, wherein the plurality of ribs defines a plurality of channels that are in communication with each other.
12. 12. The phacoemulsification needle defined in claim 1, wherein the plurality of outwardly extending projections extend radially outwardly from the second circumference.
13. 13. The phacoemulsification needle defined in claim 1, wherein the cannula is cylindrical.
14. The phacoemulsification needle defined in claim 1, wherein the longitudinal channel is expanded to the tip in a shape that is selected from the group consisting of a cannula shape, a horn shape, and a shape of stepped multi-cameras.
15. 15. The phacoemulsification needle defined in claim 1, wherein the phacoemulsification needle is machined from the single piece of titanium.
16. 16. A phaco-emulsification needle? comprising: a cannula having a proximal end, a distal end, a middle region, an outer circumference and a longitudinal channel extending through the cannula from the proximal end to the distal end; a hub disposed at the proximal end, the longitudinal channel extending through the hub; and a tip that is disposed at the far end; wherein the middle region comprises a portion having a plurality of grooves that are oriented longitudinally on the outer circumference of the cannula.
17. 17. The phacoemulsification needle defined in claim 16 in which the longitudinal channel has a first cross-sectional area and, in the middle region, the channel has a second cross-sectional area that is smaller than the first area. of cross section.
18. 18. The phacoemulsification needle defined in claim 16, wherein the plurality of longitudinally extending channels are spaced equidistantly around the second circumference.
19. 19. The phacoemulsification needle defined in claim 16, wherein the plurality of longitudinally extending grooves define a plurality of longitudinally extending projections and which are interposed between respective grooves of a plurality of longitudinally extending grooves, where at least some of the projections extending longitudinally are hollow.
20. 20. The phacoemulsification needle defined in claim 16, wherein the plurality of longitudinally extending ribs are aligned in a mutually parallel relationship.
21. 21. The phacoemulsification needle defined in claim 20, wherein the plurality of longitudinally extending ridges form a spiral around the middle region.
22. 22. The phacoemulsification needle defined in claim 16, wherein the plurality of longitudinally extending ribs are in communication with each other.
23. 23. The phacoemulsification needle defined in claim 16, wherein the cannula is cylindrical.
24. 24. The phacoemulsification needle defined in claim 16, wherein the phacoemulsification needle is machined from the single piece of titanium.
25. 25. The phacoemulsification needle defined in claim 16, wherein the longitudinal channel is expanded to the tip in a shape that is selected from the group consisting of a cannula shape, a horn shape, and a shape of stepped multi-cameras.
26. 26. A phacoemulsification needle comprising: a cannula having a proximal end, a distal end, a first circumference, a middle region having a second circumference, and a longitudinal channel extending through the cannula from the end next to the far end; a hub disposed at the proximal end, the longitudinal channel extending through the hub; and a tip disposed at the far end and a hollow sleeve disposed in the medical region having said hollow sleeve having an outer surface, and forming a portion of the hollow sleeve a plurality of outwardly extending projections, which are oriented longitudinally, arranged from the outer surface.
27. 27. The phacoemulsification needle defined in claim 26, wherein the second circumference is smaller than the first circumference.
28. 28. The phacoemulsification needle defined in claim 26, wherein the protrusions have an external diameter, and the external diameter of the protrusions is flush with the first circumference.
29. 29. The phacoemulsification needle defined in claim 26, wherein the longitudinal channel has a first cross-sectional area and in the middle region, the channel has a second cross-sectional area that is smaller than the first area. of cross section.
30. 30. The phacoemulsification needle defined in claim 26, wherein the plurality of outwardly extending projections form a plurality of projections that are spaced equidistantly around the outer surface.
31. 31. The. phacoemulsification needle defined in claim 30, wherein at least part of the plurality of ribs are hollow.
32. 32. The phacoemulsification needle defined in claim 30, wherein the plurality of ribs extend radially outwardly from the outer diameter.
33. 33. The phacoemulsification needle defined in claim 26, wherein the cannula is cylindrical.
34. 34. The phacoemulsification needle defined in claim 26, wherein the hollow sleeve is formed from an elastomeric or soft plastic material.
35. 35. The phacoemulsification needle defined in claim 26, wherein the longitudinal channel is expanded to the tip in a configuration that is selected from the group consisting of a cannula shape, a horn shape, and a stepped multi-chamber shape . RESJ EÜ A phaco-emulsification needle provided for use with a plastic or elastomeric liner, the needle having a portion of a mid region defining a plurality of outwardly extending projections that form longitudinally oriented grooves that provide irrigating flow regimes appropriate to the anterior chamber of the eye in even when the entry cut compresses the sleeve against the outer surface of the needle, thereby reducing the risk of collapse of the anterior chamber due to inadequate irrigating flow and reducing the risk of excessive transmission of heat at the entrance cut.