The original Hessburg-Barron Vacuum Trephine? was developed in collaboration with Dr. Philip Hessburg, president of the Detroit Institute of Ophthalmology. The instrument is fabricated from the highest grade stainless steel and FDA-approved polymer materials. It is delivered in a sterile transparent plastic tray with a hermetically-sealed Tyvek lid, which is sealed inside an outer hermetic pouch so that attending personnel can open the pouch and transfer the sealed tray onto a sterile field without touching the tray. The operating physician or gloved assistant can then open the tray and place the trephine onto the sterile field for use.
The Hessburg-Barron Vacuum Trephine? was developed to be self-contained, with no need for auxiliary vacuum equipment. It uses a simple hand-operated syringe to create a vacuum to hold the cornea against the trephine during trephination. This causes the cornea to be held in its natural contour, thereby producing a perpendicular incision in the cornea to provide an optimal recipient opening for donor tissue.
As shown in the schematic on the right, an inner ring and outer ring form a vacuum chamber when the unit is placed on the cornea. The blade is located only 0.07 mm inside of the inner ring, which allows for secure support of the cornea during trephination.
As with all BPI trephine products, the blade of the Hessburg-Barron Trephine? ?is fabricated from the hardest stainless steel that is available, and its manufacture employs a proprietary, multiple-stage honing of the blade edge to give unsurpassed sharpness. Some other manufacturers of vacuum trephines construct their instruments with thin (0.1 mm thick) bent razor blades that are not perfectly circular and are easily nicked or chipped. BPI uses a process that was developed to yield quality blades that are uniquely suited for corneal surgery. The blades in the BPI trephines are perfectly circular and have no edge interruption as is found with trephines fabricated from bent razor blades.
To facilitate optimal location of the trephine as it is positioned on the patient?s eye, fine crosshairs are incorporated inside each trephine blade. These help physicians to align the trephine with the center of the desired cut. The crosshairs are positioned in a way such that they are as close to the surface of the cornea as possible without contacting the epithelium. The blade is mounted in a spoke adapter that allows the blade to be precisely lowered at a rate of 0.25 mm per each revolution.
The Hessburg-Barron Vacuum Trephines? come in 11 diameters, ranging from 6.0mm to 9.0mm. There is a family of donor cornea punches that can be used in conjunction with the Hessburg-Barron Vacuum Trephines?, the punch sizes being available in 0.25 mm- diameter increments to provide flexibility in matching donor tissue with the incision made by the trephine. The Hessburg-Barron Vacuum Trephines are available directly from Barron Precision Instruments or from JedMed Instrument Company.