Case for microkeratome blade

A small case for protecting a microkeratome blade while allowing inspection and cleaning of the blade cutting edge incorporates adjacent walls which are hinged together to open and close relative to an inserted microkeratome blade. In position, when the case is closed the blade is set in a recess in one of the walls and held in position by an opposing surface on the other wall. Windows encompassing the cutting edge in each of the walls allow visual inspection and cleaning, if desired. When the case is opened, a converging guide groove extending from a side of one wall into the blade unit and to a point behind the cutting edge allows a surgeon to insert and guide a forceps into the blade unit so that it can be gripped and removed without contacting the cutting edge.

FIELD OF THE INVENTION

This invention relates to surgical instrument holders and more specifically to a case for retaining microkeratome blades up to the time of use at the operative site.

BACKGROUND OF THE INVENTION

Microkeratome blades are now widely used for in situ ophthalmic surgeries employing laser correction. In such surgical systems, the eye is drawn into a fixed exposed position so that a cutting blade can move in a curved or linear path across the cornea, tangential to the curve of the eye, and at a preselected depth. The blade thereby cuts a flap of controlled thickness in the cornea across the center of the eye. The flap can then be raised, so that a computer controlled laser beam can be directed against the exposed portion and corneal tissue selectively ablated to introduce the needed optical correction. The flap is then returned back into position on the principal body of the cornea and no further surgical treatment such as a suture is typically needed.

The blades used in these operations are small (about ½ inch in cutting edge length) and are formed as an integrated unit with a small holder or driver, via which the blade can be reciprocated in oscillating fashion. The nature of the incision cut into the cornea is highly dependent upon providing and preserving a precise cutting edge on the blade, inasmuch as an irregular tissue surface, such as a serrated or torn surface resulting  from the cut, affects both the vision of the patient and the healing process. In addition at least the cutting edge portion of the blade must be assuredly sterile.

Microkeratome blades are usually used only for a single operation, because of the need for a sharp, uniform cutting edge and the dangers of cross contamination. Prior to use they are conventionally kept in small cases, in sterile condition within an enclosing package. After the sterile package is opened, the blade is withdrawn from its case at the operative site. Prior to extraction of the blade from its case, surgeons often wish to inspect the cutting edge under magnification, and swab the cutting edge to make sure that it is antiseptically clean. The cases heretofore used for these purposes have not permitted complete inspection and treatment of both sides of the cutting edge without removal from the case, and have been structured in such ways as to require special tools or intricate or dexterous manipulation to remove the blade from the case.

SUMMARY OF THE INVENTION

A case for storage and presentation of a microkeratome blade at an operative site comprises a hinged body, which clamps the blade and its driver securely between opposing surfaces. Each of the halves of the hinged body are apertured around the cutting edge of the inserted blade, such as to permit access for visual inspection and, if desired, assured sterilization. The hinged body can be opened by separation of wing-shaped clasps to reveal the blade and driver in retained position. The blade edge is forceps accessible from the side of the case via a tapered opening with converging surfaces which guide the forceps tips to an exposed portion adjacent the blade cutting edge. Thus in a single guided motion a surgeon can grasp and remove the blade by use of conventional forceps without danger of contacting the cutting edge, so as to place the  blade and its associated driver into the microkeratome machine. The halves of the body can be molded as an integral unit about a central hinge, with pins on one half engaging mating post holes on the other to permit secure retention that is readily overcome manually when the blade is to be used.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIGS. 1–5, a microkeratome blade10(FIGS. 1,2and5) has a cutting edge12at what will be called its front and a single back edge14that is curvilinear in outline. The blade10includes an aperture16near its back edge in which  an upstanding boss part18of a triangular (in section) driver20is secured. Microkeratome blades typically have a straight front edge although the remaining periphery can be of different shapes, and the driver as well, although the driver forms a three dimensional block that protrudes from the blade surface. In the microkeratome machine, the cutting edge12of the blade10is driven from side to side by elements acting on a slot (not shown) in the driver20, as the blade is advanced through the cornea. The triangular-sided driver20(best seen inFIG. 5) seats in a mating recess to position and hold the blade10, as will be described.

The body of a case30for the blade10may be molded of a single unitary part of suitable synthetic resin such as polyvinyl. Although two or more pieces can be employed the angle molded part has cost and convenience advantages. The two halves of the case30are hinged about an integral hinge line32formed by two curved segments34,35joined by a small but adequately strong central hinge or spine36(FIG. 4). The two major halves of the case30extend oppositely from the central hinge36, but are not symmetrical. As seen inFIG. 3, what is to be the lower part40of the case30includes a wing-shaped clasp42extending from its periphery opposite the hinge36, on which is imprinted an embossed or relief pattern designating “up”, for the guidance of the surgeon. This lower half40includes an angled driver recess44(the internal angle, which mates with the triangular cross-section of the driver20, is best seen inFIGS. 4 and 5) within a raised border46. Two adjacent postholes48,49are positioned to receive pins for securing the halves together, although other frictional retaining elements can be used for releasable clamping. On the opposite side of the driver recess44is a lower window50,  the midregion of which is in alignment with the cutting edge12of the microkeratome blade10when installed. This relationship is illustrated most clearly inFIGS. 2 and 5.

At one side of the driver recess44and the window50a converging forceps ramp54(FIGS. 1–3particularly) that converges on three sides extends inwardly from one side of the lower half40toward a space immediately adjacent side of the inserted blade10, as seen inFIG. 2. The forceps ramp54angles upwardly as the sides converge to the side of the blade10, so that with an open forceps the surgeon need only insert the tip portion into the forceps ramp54and follow the inclined surface to engage the blade10behind its cutting edge12.

On the opposite side of the case30from the centerline32, the upper half60of the body includes a pair of pins62,63each positioned, when the hinged assembly is closed, to engage in a different one of the post holes,48,49. At closure a window65in the face of the upper half60encompasses the cutting edge12of the blade10providing visual and physical access from this side as well. The upper half of the upper window65includes a beveled edge68(seeFIGS. 4 and 5) to facilitate access to the cutting edge12for inspection and/or safeguarding sterilization. When the two halves40,60of the case30are closed together, the pins62,63fit in the postholes48,49with a light press fit. A wing-shaped clasp70on the upper half60of the case30includes raised dimples72which provide surface irregularities which aid in finger control of the wing clasps42,70during both opening and closing.

It can thus be seen that a relatively low cost blade case is provided that has all the desired attributes, namely secure retention of a protected blade in position, with the blade and holder being fully visually inspectable from both sides, as well as accessible for  cleaning and sterilization if desired, but at the same time so designed as to allow a surgeon to seize and remove the blade in simple but assured fashion.

Although there have been described above various forms and modifications in accordance with the invention, the invention encompasses all variations and versions within the scope of the appended claims.