1. Field of the Invention
The present invention relates to a multi-component fiber optic handpiece that is particularly safe, practical and economical for use in medical laser treatment.
2. Information Disclosure Statement
An optical fiber handpiece is generally used in ophthalmic, dental, and orthopedic surgical procedures where the treatment area is confined and particularly difficult to reach. Typically, laser light is transmitted from a laser source through an optical fiber to the treatment site. The optical fiber terminates proximally in a laser connector for connection to the laser source and terminates distally in a handpiece, which is manipulated by the surgeon.
As can be appreciated, because of the potential for spreading infection, a handpiece used during one procedure cannot be used with another patient in a subsequent procedure unless some form of sterilization is performed. Unfortunately, the handpieces that were initially introduced to the marketplace were not designed to withstand sterilization procedures and were therefore discarded after use on a single patient. However, this method is not cost-effective.
Since that time, attention has been given to improving the design of the handpiece so that it can be resterilized. Various handpieces have been manufactured and sold which can be resterilized using gas techniques. Unfortunately, gas sterilization is a relatively time consuming and costly approach. In contrast, high temperature steam sterilization in an autoclave is faster and less expensive. However, handpieces were generally incapable of withstanding the high temperatures that are encountered in an autoclave.
U.S. Pat. No. 5,304,172 provides a partial solution to this problem by carefully selecting materials for the handpiece body that can withstand the maximum heat that is encountered in an autoclave, which is about 132 degrees centigrade. However, the optical fibers that are incorporated into the handpiece failed or were damaged during reuse. The disclosed fiber optic probe utilizes a two-piece optic fiber to deliver laser radiation through the handpiece. The two pieces are held in place by spring-biased ferrules that force the mating ends of the fibers together. No means are disclosed to protect the optical fiber during insertion or prior to adhesively securing the optical fibers to the ferrules.
It has been found through research that exposure to the input face of the fiber to the cycling of the pressurized steam occurring during sterilization in an autoclave enhanced and accelerated the formation of cracks in the silica glass at the fiber surface. It has been previously reported that water molecules in the presence of cracks in glass can accelerate the breakdown of bonds. (See, xe2x80x9cThe Fracturing of Glass,xe2x80x9d Michalske and Bunker, Scientific American, December, 1987, pages 122-129). As can be appreciated, the high temperatures generated in an autoclave can force steam molecules into any microscopic cracks that are present in the fiber, accelerating the breakdown of atomic bonds. It is also believed that when the autoclave is rapidly depressurized, turbulence is created, forcing debris into the input face of the fiber thereby increasing the damage. These cracks and other imperfections lead to breakdown of the fiber during use.
Accordingly, it would be desirable to provide a handpiece that could be sterilized in an autoclave without the complications associated with the prior art.
One possible solution is to remove the optical fiber prior to resterilization. However, the fiber can be damaged during insertion and an adequate means to removably lock the fiber in position would be required. Misalignment of the fiber is prevalent when the fiber is not permanently incorporated into a handpiece device, which can result in damage to the fiber during assembly and actual use of the handpiece.
U.S. Pat. No. 5,489,205 discloses a syringe tip locking assembly comprising means for compressing a handpiece body against a removable syringe. The four part holding mechanism described may work for a metal syringe, but will not necessarily work on a glass fiber. In a holding means such as that disclosed, if the fiber were not perfectly centered prior to being locked in place, it would be possible to lock a fiber with only 3 of the 4 prongs, thereby placing unbalanced forces on the fiber. Stress crazing could result in catastrophic failure of the fiber.
It is therefore an object of the present invention to find a solution to the handpiece-fiber combination that is both economical and practical for medical laser treatment.
It is an object of the present invention to provide a handpiece-fiber combination without the complications associated with the prior art. In particular, a multi-component handpiece is described that is safe, practical and economical for medical laser treatment.
It is another aim of the present invention to provide a means to protect the optical fiber before and during insertion into a handpiece device.
It is a further aim of the present invention to describe a means to prevent longitudinal movement of an optical fiber during surgical laser therapy.
It is an even further aim of the present invention to eliminate the transmission of disease from one patient to the next without having to dispose of the entire handpiece following every laser procedure.
Briefly stated, the present invention describes a multi-component handpiece that is both economical and practical for surgical laser treatment. A disposable optical fiber is inserted into a reusable handpiece. The distal end of the optical fiber is protected by a micro-walled protective tube to prevent the disposable fiber from chipping before and during insertion into the handpiece. Once the optical fiber is protected, it is inserted into the handpiece by threading the optical fiber through the cap, body, and needle cannula of the handpiece until the fiber extends slightly beyond the distal end of the cannula. The micro-walled protective tube is removed from the end of the optical fiber, the optical fiber is positioned, and the cap is tightened. The cap and body of the handpiece cooperate to produce a tight friction fit that prevents longitudinal movement of the optical fiber. The tight friction fit holds the optical fiber in place without the use of adhesives to eliminate the problem of residual glue on the handpiece device and to allow for facilitated removal of the disposable fiber after use. Furthermore, a disposable fiber allows for convenient resterilization of the handpiece, eliminating the transmission of disease from one patient to the next without having to dispose of the entire handpiece following every laser procedure.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description read in conjunction with the accompanying drawings.