Patent Application
20090157111
The present invention is related to microsurgical probes and more specifically to ophthalmic microsurgical probes such as vitrectomy probes.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Ophthalmic surgical procedures on the posterior segment of the eye generally require the cutting and/or removal of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic transparent fibers that are often attached to the retina. Therefore, cutting and removal of the vitreous must be done with great care to avoid traction on the retina, i.e., the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself.
The use of microsurgical cutting probes in posterior segment ophthalmic surgery is well known. Such vitrectomy probes are typically inserted via an incision in the sclera near the pars plana. The surgeon may also insert other microsurgical instruments such as a fiber optic illuminator, an infusion cannula, or an aspiration probe during the posterior segment surgery. The surgeon may perform the surgical procedure while viewing the eye under a microscope.
Conventional vitrectomy probes typically include a hollow outer cutting member, a hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, and a port extending radially through the outer cutting member near the distal end thereof. Vitreous humor is aspirated into the open port, and the inner member is actuated, closing the port. Upon the closing of the port, cutting surfaces on both the inner and outer cutting members cooperate to cut the vitreous, and the cut vitreous is then aspirated away through the inner cutting member.
During posterior segment ophthalmic surgery, it is generally desirable to remove as much of the overlying vitreous as possible prior to any procedure to repair the underlying retina. However, a surgeon is limited in how close to the retina he or she can dispose a conventional vitrectomy probe due to both the probe's geometry and due to the risk of pulling or tearing vitreous strands near the retina that could lead to separation of the retina. Therefore, a need continues to exist for an improved vitrectomy probe that does not suffer from the above-described limitations.
In accordance with one aspect of the present application, an end-cutting vitrectomy probe is provided. The probe includes a hollow sleeve having an opening in the sleeve at its distal end portion, and a tapered annular surface disposed in the interior of the sleeve's distal end. The end-cutting vitrectomy probe further includes a cutting member having a distal end defining a circumferential cutting edge, where the cutting member is slidably disposed within the hollow sleeve. The cutting member is movable towards the distal end of the sleeve, such that the circumferential cutting edge frictionally engages the tapered annular surface within the hollow sleeve, to thereby cut vitreous tissue disposed therebetween. The end-cutting vitrectomy probe may further include a drive mechanism for slidably displacing the cutting member within the hollow sleeve in a reciprocating manner, such that the cutting member oscillates between a position of engagement and disengagement with the tapered annular surface. The end cutting vitrectomy probe may further include a pneumatic device configured to apply a vacuum to the interior of the hollow sleeve, for aspirating vitreous tissues in through the opening such that portions of the vitreous tissues may be cut.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Various embodiments and their advantages are best understood by referring to
It is essential to ensure that proper cutting of vitreous between the cutting member and end of the sleeve occurs. This is critical, since vitreous tissue strands near the retina must be cut cleanly to avoid pulling of vitreous strands that could cause pulling the retina away from the eye wall. Accordingly, one important aspect of the present application addresses the engagement between the cutting member and a cutting block, plate or disc element, to provide for alignment of the cutting member that ensures adequate cutting engagement for cleanly cutting vitreous tissues.
As shown in
Referring to
Referring to
Alternatively, the tapered annular surface on the disc element may form part of a raised portion 118 on a disc element 111, as shown in
The drive mechanism 130 may further be configured to rotate the cutting member 120 within the sleeve 102, as shown by arrow 132 in
When the cutting member 120 is moved toward the distal end of the sleeve 102 into a position of contact with the disc element 110, it is essential to ensure that proper engagement between the circumferential cutting edge 122 and the disc 110 occurs. This is critical, since vitreous near the retina must be cut cleanly to avoid pulling of vitreous strands that could cause pulling the retina away from the eye wall. Accordingly, one important aspect of the tapered annular surface 112 on the disc element 110 is to provide for alignment of the cutting member 120 to ensure adequate cutting engagement for cleanly cutting vitreous. Upon contact between the cutting member 120 and the tapered annular surface 112, the tapered annular surface 112 guides or adjusts the circumferential cutting edge 122, to concentrically align the end of the cutting member 120 with the tapered annular surface 112. This alignment ensures that a substantial portion of the circumference of the cutting edge 122 engages the tapered annular surface 112, to thereby provide for a clean cut of any vitreous between the cutting edge 122 and the disc's tapered annular surface 112.
It should be noted that some embodiments may include only the sleeve 102, disc 110 and cutting element 120 as part of a disposable, easily-replaced component, for use with any number of end-cutting vitrectomy probe systems. Alternatively, other embodiments may include one or more of the above mentioned elements. In a second embodiment, an end-cutting vitrectomy probe assembly is provided that includes a cutting member within a hollow sleeve having an opening in a side wall of the sleeve's distal end portion, and a tapered annular surface disposed in the interior of the sleeve's distal end. The cutting member is movably disposed within the hollow sleeve, and has a cylindrical distal end defining a circumferential cutting edge. When the cutting member is fully displaced against the distal end of the sleeve, it frictionally engages the tapered annular surface within the hollow sleeve, to thereby cut any vitreous tissue disposed between the circumferential cutting edge and the tapered annular surface. The end-cutting vitrectomy probe assembly further includes a pneumatic device configured to apply a vacuum to the interior of the hollow sleeve, for aspirating vitreous tissues in through the opening and into the interior of the hollow sleeve, such that portions of the vitreous tissues may be drawn through the opening and cut. The end-cutting vitrectomy probe assembly further includes a drive mechanism for slidably displacing the cutting member within the hollow sleeve in a reciprocating manner. This permits the cutting member to oscillate between a position of engagement with the tapered annular surface, and a position spaced apart from the tapered annular surface, to thereby provide for repetitive cutting action.
In another aspect of the present application, the end-cutting vitrectomy probe is further configured to provide for alignment of the cutting member to ensure adequate cutting engagement for cleaning cutting vitreous tissues. The drive mechanism may be configured to rotate the cutting member in a first rotation direction as shown in
From the above, it may be appreciated that the present invention provides improved apparatus and methods of performing vitrectomy surgery. The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art.
It is believed that the operation and construction of the present invention will be apparent from the foregoing description. While the apparatus and methods shown or described above have been characterized as being preferred, various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims.
