Grooved optical fiber jacket

An optical fiber is disclosed which includes a protective outer jacket. The outer protective jacket is grooved to include one or more peripheral grooves formed into the jacket. In operation of a laser device, laser energy passes through the optical fiber to the distal tip of the optical fiber. As the distal tip erodes, the outer protective jacket also erodes in a controlled fashion such that portions of the outer jacket flake off as the fiber tip erodes to the position of the peripheral grooves formed in the outer jacket rather than in a random fashion.

FIELD OF THE INVENTION

This application relates to optical fibers for medical laser devices and in particular to coverings or jackets for such optical fibers and improvements in such jackets to enhance their ability to rupture and self-destruct when in operation.

BACKGROUND OF THE INVENTION

Optical energy which is produced by medical lasers is often delivered to a target tissue through the use of an optical fiber or flexible hollow waveguide. A wide variety of medical lasers with appropriate delivery systems are known and used for wide spectrum of treatments, including kidney stone or other stone disintegration, tissue ablation, and tissue coagulation, the way of example only. However, optical fibers and waveguides tend to be fragile and requires some degree of the mechanical support. This usually involves the placement of a polymeric, Teflon or other suitable material jacket covering and surrounding the optical fiber to provide such support.

Moreover, an optical fiber or waveguide consists of a concentric core element surrounded by one or more layers of cladding materials. In some cases, the core element may be a silica core or simply a hollow waveguide. The cladding material in a hollow waveguide may be silver or other internal coating while, in the case of an optical fiber, such cladding material may be a transparent solid material. A polymeric jacket may have an appropriate optical characteristic to serve not only as a protection for the cladding element but also serve as a secondary cladding material in addition to its mechanical support purposes.

During treatment, in which laser energy is passed through an optical fiber or waveguide's proximal end, the laser beam energy will exit from the distal tip of for example, the optical fiber. This distal tip will tend to become eroded during laser treatment due to the intensity of the laser's power. This is because in medical treatment such as ablation treatments or treatments in which the laser is used to disintegrate or break up for example kidney stones, the higher level of energies and fluence which are delivered through the optical fiber and the interference of tissue or stone fragments tend to cause erosion and disintegration of the fiber tip. This tip erosion is known to affect mainly the fiber core, the cladding materials, and, as mentioned, the fiber tip. Due to the materials and structure of the jacketing material there is less proportionate erosion of the jacketing materials.

During operation, as the distal tip of the fiber erodes and diminishes in length, the jacket itself tends not to erode, as mentioned above, at the same rate.FIGS. 1A and 1Billustrate this phenomena. As can be seen inFIG. 1A, whereas the fiber tip 1 has eroded there is little erosion in the jacket material 2. Since, in a number of procedures, it is necessary or at least desirable to place the fiber tip against the bodily material that is to be ablated, it can be seen inFIG. 1Athat the remaining jacket material prevents such contact. In addition, as can be seen inFIG. 1B, the jacket material 4, due in part to heating from the laser beam energy, may become jagged and may further make it difficult to contact the bodily material to be ablated. Another disadvantage is that the field of vision may be limited. Finally, when the jacketing material those fragment and separate from the remainder of the optical fiber and jacket combination, fragments which have separated may be large enough to interrupt the optical path of the laser beam, further complicating the medical procedure.

Thus, what is needed is an optical fiber jacket which eliminates the problems described above yet which provides an orderly destruction, erosion or disintegration of the optical fiber jacket more in synchronization with the erosion of the optical fiber tip itself.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Turning now toFIGS. 2A,2B, and3A-3E, these figures illustrate one or more aspects of the present invention. The present invention incorporates one or more peripheral grooves into the outer jacket material. These peripheral grooves may totally encompass or only partially encompass the periphery of the jacking material. The grooves may be a single groove or number of grooves, and the distance between grooves may be selected to place such grooves close to or far apart from one another. The depth of the grooves may also vary. The jacket, as mentioned above, may be either a polyimide, Teflon or other suitable material and generally has uniform thickness along the optical fiber waveguide. In one or more aspects of the present invention, the depth of the groove or grooves may be: less than the jacket thickness itself, be nearly the thickness of the jacket, or even equal to or exceed the thickness of the jacket itself.

FIGS. 2A and 2Billustrate an optical fiber in an embodiment which includes a peripheral groove14in the jacket material of the present invention. While a single groove14is illustrated, it is understood that multiple grooves may be incorporated. As illustrated inFIG. 2A, the distal tip of the optical fiber has deteriorated to a position in which the peripheral groove14is almost reached. InFIG. 2B, the deterioration is to a position in which the peripheral groove14has been reached. InFIG. 2A, an optical fiber10has a jacket material12into which is incised a peripheral groove14. As shown inFIG. 2A, this figure illustrates the environment on the assumption that the laser beam has been activated and that the fiber tip has eroded more than the jacket itself. Excess jacket surplus16is shown as remaining attached to the optical fiber, and, as illustrated, may interfere with the operation of the laser beam since the axis jacket material is shown as partially obstructing the optical fiber path.FIG. 2Billustrates the operation of the peripheral groove14once the optical fiber tip has eroded to the position of the peripheral groove14. The weakness introduced by grooving the jacket causes the jacket material16to separate from the optical fiber itself in a controlled manner. Previously, without the peripheral groove(s) of the present invention, the breakaway of the excess jacket material was uncontrolled and somewhat random, increasing the likelihood of interference with the operation of the laser beam due to the presence of jacket material in the optical path of the laser beam. Thus, as can be seen inFIG. 2B, the excess jacket material does not interfere with the optical fiber path so that the medical procedure may proceed without such interference. According to an aspect of the present invention, the peripheral groove lines may create weaker peripheral lines such that the jacket is more easily breakable and tends to yield under mechanical and thermal strains imposed by the operation of the laser beam through the optical fiber. As a result, the excess surplus of jacket material will simply tear off at the peripheral lines and avoid further interaction with the laser beam which, as mentioned, may negatively affect the efficiency of the laser treatment.

FIGS. 3A through 3Dillustrate various implementations of peripheral grooves in an optical fiber. InFIG. 3A, for example, a plurality of grooves20are shown formed into the jacket material22. The distance between the peripheral grooves may be selected according to the material of the jacket, the type and power of the laser beam, such other criteria such as the material of the optical fiber itself. Clearly, if it is desired that there be smaller portions of jacketing material dislodges, the peripheral grooves may be spaced closer to one another. This may be desirable because in a number of medical procedures involving the use of lasers and optical fibers, the volume around the bodily material to be ablated may be surrounded by a fluid material. In such cases, when a portion of jacketing material is dislodged, it will tend to float around in the fluid material and may interfere with the laser beam attempting to contact and ablate the bodily material. Smaller pieces of jacketing material will tend to be less interfering with the application of the laser beam.

FIG. 3Billustrates two types of groove shapes or configurations. These include a circular shaped groove30and an elliptically shaped groove32. Other shapes or configurations may also be used so long as the group structure is such that it tends to break apart as the erosion of the tip approaches or nearly approaches the grooves. The grooves may be formed only in the distal portion of the optical fiber or in other portions as well.

FIG. 3Cillustrates an optical fiber40which has surrounding it a jacket42. Into the jacket42, one or more grooves44and46may be formed into the jacket42. The groove depth may be the depth of the jacket itself as shown in42or may be less than the depth of the jacket shown in46. Grooves of the type shown in44and46may be used alternatively such that, by way of example only, thy groove of the type44may alternate with grooves of type46and a desired sequence or organization. As shown inFIG. 3C, groove44reaches down to the cladding48itself. This is also shown inFIG. 3D.

FIG. 3Eillustrates yet another embodiment of the present invention. InFIG. 3E, the outer jacket50is formed with not only one or more circular shaped grooves52but also grooves54formed in a direction along the optical axis of the optical fiber and in contact with the one or more circular shaped grooves52. In this embodiment, the longitudinal sections56formed in the jacket will tend to “splay” away from the optical fiber tip once the optical fiber tip has been eroded to the distal portion of the longitudinal sections56. The portions56move away from the periphery of the optical fiber and tend not to interfere with the operation of the optical fiber tip. Once the optical fiber tip has eroded to the level the peripheral groove52, the longitudinal portions56will tend to break away entirely from the jacket50.

According to another aspect of the present invention, a method is disclosed using optical fibers for a medical laser procedure. This method includes forming one or more peripheral grooves towards the distal end of an optical fiber waveguide into the jacketing material prior to the medical laser procedure. The method may further include using an adjusted fiber stripper or cleaver which is designed to create the peripheral grooves into an optical fiber or waveguide jacketing material. These grooves may partially or totally penetrate the thickness of the jacketing material.

In order to form a peripheral grooves into the jacketing material of the types described above, a number of different modalities may be utilized. For example, a wire stripper of known construction may be utilized to cut through the desired amount of jacketing material without compromising the cladding material surrounding the optical fiber or compromising the optical fiber itself. Known wire strippers will strip the insulation off of wires and have adjustable penetration depths that may be set using a plurality of cutting faces. Such a device may create one for more grooves simultaneously. According to another aspect of the invention, the one or more peripheral grooves may be created by a single punch of the stripper. In yet another aspect of the invention such a device may create one or more grooves by a punching movement followed by rotation movement so that the full circumference of the outer jacket, at the point of grooving, is fully encompassed. Such a rotation movement may require rotating the device at an angle which is a function of the number of proving elements in the device. For example one type of grooving teeth may require almost or all of a 360° rotation, while two opposite teeth may perform the same function using only a 180° rotation.

Although the particular embodiments shown and described above will prove to be useful in many medical procedures involving the use of jacketed laser fibers to which the present invention pertains, further modifications of the present invention will occur to persons skilled in the art. All such modifications are deemed to be within the scope and spirit of the present invention as defined by the appended claims.