Surgery – Instruments – Optic – otic or oral scrapper or abrader
Reexamination Certificate
2000-09-11
2003-06-10
Worrell, Danny (Department: 3765)
Surgery
Instruments
Optic, otic or oral scrapper or abrader
Reexamination Certificate
active
06575989
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a type of microsurgical instrument used in treatment of intraocular diseases such as proliferative vitreoreitnal disorders. The microsurgical tool may be configured to provide the surgeon with improved methods for the removal of proliferative membranes from the surface of the retina or for the removal of residual cortical vitreous proliferative membranes from the areas surrounding the macular hole.
2. Description of the Background
Proliferative vitreoretinal disorders are manifested in the intraocular cavity of the eye by the growth of proliferative membranes on the neurosensory retina. In the conventional treatment for vitreoretinal disorders, the membranes are removed from the neurosensory membranes with various microsurgical instruments such as intraocular forceps and intraocular picks. The microsurgical instruments are introduced into the intraocular cavity through an incision in the eye, and the membranes are carefully removed from the neurosensory surface of the retina without causing tears or hemorrhages.
Depending on the stage of the disorder and the growth of the membranes, the membranes have a different texture and composition. Mature membranes tend to be removed with less complication when compared with the removal of immature membranes. With conventional intraocular forceps and picks, the surgeon is generally able to remove mature membranes from the surface of the retina as a film. When the mature membranes are removed as a film, more complete removal from the surface of the retina is possible with a lower chance of membranes remaining on the surface. On the other hand, immature membranes tend to be friable in nature because they have not acquired the necessary cross-section to be removed with conventional intraocular picks and intraocular forceps. Being friable in texture, the immature membranes do not peel of as a film, and consequently, immature membranes, which are not fully removed during surgery, may be a nidus for future membrane formation, causing the patient to undergo future operations for removal of these membrane formations.
A recent invention, effective in the treatment of proliferative vitreoretinal disorders, has been developed to mechanically remove mature and immature proliferative membranes from the neurosensory surface of the retina without the use of intraocular picks or intraocular forceps. This invention described by Tano, et al. (U.S. Pat. No. 5,921,998 ('998), incorporated herein by reference) uses an abrasive media on a tip of the microsurgical instrument to scrape the membranes from the surface of the retina. The advantages of this invention are a reduced chance of retinal tearing and hemorrhaging and the ability to remove membranes despite the stage of the growth of the membrane.
The abrasive media of the '998 instrument is affixed on the distal end of a straight probe. The straight probe is introduced into the eye through a cannula that is inserted through an incision into the intraocular cavity in the eye. The abrasive media described in the '998 patent may be diamond, silicone carbide, quartz, or alumina. The abrasive particles are biologically inert and bonded to the distal end of the probe in a manner such that the shedding of particle into the retinal tissue is avoided. By using different instruments having tips with varying types of abrasive particles, it is possible for the surgeon to more carefully separate and remove these proliferative membranes from the retina without causing damage to the retina. The removal rate may be varied depending upon the type of particles that are bonded to the tip of the microsurgical instrument, where the rate of tissue removal is in proportion to the coarseness of the particles bonded to the tip. The surgeon may more carefully control the removal rate of the proliferative membranes ensuring retinal tears and other damage to the retina does not occur, in distinction to other methods that use intraocular picks and forceps to remove the proliferative membranes.
During surgery for the treatment of vitreoretinal disorders, the surgeon may use in conjunction with these previously mentioned surgical instruments other more common surgical instruments to execute the other functions required during the operation. These microsurgical instruments are also introduced into the intraocular cavity through the cannula. A common instrument is one that is designed to deliver an aspiration source locally to an area to remove tissue. Another common instrument is used to provide infusion to the surgical area for irrigation and flushing as required. The surgeon may use a combination of these instruments and techniques to condition the surface of the retina and remove membranes by the devices previously mentioned. In some conventional instruments, a single instrument capable of performing both of these functions has been used to perform both aspiration and infusion functions.
Other common instruments aid in the visualization of the surgical site. Often the surgeon wishes to illuminate the surgical site or surface of the retina for more complete visualization of the membranes. In conventional instruments, the surgical site may be illuminated or visualized by a fiber optic cable fitted into a probe that is inserted through the cannula into the eye. The fiber optic cable may also be fitted onto a conventional probe to transmit a video picture signal back to a display to give the surgeon a visual image of the surgical site on the surface of the retina. This enhanced visual representation of the surface of the retina allows the surgeon to evaluate the operation and to more completely remove the proliferative membranes during the operation.
Generally, during the course of the operation, the surgeon must alternate between probes to carry out the specific function required at a particular stage of the operation. When changing probes, the old probe must be removed from the cannula and a new probe must be inserted. Generally, the type of cannula used is either straight or curved depending upon the instruments to be used during the surgery and the location of the surgical site in relation to the incision site. Curved probes cannot be inserted through straight cannulas, and straight probes cannot be inserted through curved cannulas. In a surgical procedure using these conventional instruments, the surgeon must make an initial choice to the style or cannula and instrument to be used during the operation.
Sometimes, the surgeon will find that during the course of the operation, a surgical instrument having a straight probe will not efficiently deliver aspiration or infusion to the target area. This may be due to the positioning of the incision or instrument entry site in the eye relative to the target surgical site. The surgeon may decide that a curved probe would provide better range to deliver infusion or aspiration to the surgical site. This change also requires a change in the style of cannula or the use of the probe through the eye incision itself. Such a changeover complicates the operation and often produces additional and sometimes harmful stresses on the eye. Similarly, the delivery of the optical fiber to the surgical site is generally through a straight probe so that the surgeon may directly visualize or illuminate the affected area. Curved probes may also be used with curved cannulas that are aimed to the surgical site. The changeover also complicates the operation and often produces additional and sometimes harmful stresses on the eye.
To overcome these disadvantages of prior art microsurgical instruments used during ophthalmic surgical operations, what is needed is a microsurgical instrument, which combines the functions of infusion and aspiration with abrasive membrane scraping or the functions of illumination with abrasive membrane scraping. The invention could be provided in an adjustable curved member that is adaptable to a straight cannula, thus providing the surgeon with increased range for membrane scraping. The i
Auld Michael D.
Lumpkin Christopher F.
Scheller Gregg D.
Synergetics, Inc.
Thompson & Coburn LLP
Worrell Danny
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