Cervical Biopsy Forceps: Tischler vs Kevorkian vs Schubert

Three patterns turn up on almost every colposcopy tray, and most clinicians inherit their preference from whoever trained them rather than from any comparison of the jaws. That is fine until the pathology report comes back saying the specimen is too superficial or too crushed to grade, at which point the instrument stops being a matter of habit.

Here is what actually separates the Tischler, the Kevorkian and the Schubert.

Bite figures differ between manufacturers by a millimetre or so. Treat the numbers above as the shape of the family, then confirm against the catalogue line you are actually ordering.

Tischler: the Default, and Why

The Tischler has a basket-shaped jaw in which both blades carry a cutting edge and close into a shallow cup. Because both blades cut, the tissue is severed rather than avulsed, and because the jaw is a cup rather than a flat plate, the sample arrives at the pot as a block with a recognisable epithelial surface and a base of underlying stroma.

That stromal base is the point. A colposcopic biopsy is being read to distinguish intraepithelial neoplasia from early invasion, and invasion is defined by what has happened below the basement membrane. A specimen that is all epithelium and no stroma cannot answer the question that was asked, and the report will say so.

The upper blade of most Tischler patterns is fitted with a fine tenaculum spike or a serrated lip. It anchors the jaw on a mobile cervix so the instrument bites where the colposcopist aimed rather than skidding off a wet convex surface.

The Baby Tischler is the same architecture at roughly half the bite. It is the right choice on an atrophic postmenopausal cervix, on a nulliparous cervix with a tight os, and whenever the acetowhite area is small enough that a full-size bite would remove all of it and leave nothing for a repeat.

Kevorkian-Young: the Flat-Blade Alternative

Where the Tischler closes into a cup, the Kevorkian-Young closes a rectangular upper blade onto a flat, plate-like lower blade. The lower blade sits against the cervical surface and the sample is punched down onto it.

Two consequences follow. The instrument sits lower in profile, so it reaches lesions that run out to the lateral fornix or sit flush against the vaginal wall where a bulkier basket jaw fouls the speculum blade. And the specimen it produces is a flatter slab, which some laboratories prefer for embedding because orientation is more obvious.

The trade-off is depth. A flat-blade punch is more dependent on operator technique to get adequate stroma, because there is no cup to hold the tissue block as the blade travels. On a firm cervix that is a non-issue; on a soft, friable one it can produce a thin sample.

The Kevorkian name also attaches to an endocervical curette — a small, sharp, square-tipped curette used to sample the canal above the transformation zone. It is a different instrument from the biopsy forceps and is often on the same tray. Do not let a stores request for “Kevorkian” arrive as one when you meant the other; specify pattern and function on the order line.

Schubert: the Wedge

The Schubert takes a triangular bite. In practice that means a wedge with two converging cut faces meeting at a point, rather than a rectangular or cup-shaped block.

It is the least common of the three in routine screening clinics and the most useful when the question is about a margin — where a lesion stops, whether disease extends to a particular edge — because the wedge geometry preserves a clear orientation between the surface and the deep apex. It is also used for uterine and endometrial sampling in some units.

If your clinic runs a single pattern for everything, it will not be this one. If it runs three, this is the third.

Sharpness Is the Specification That Matters

Every one of these is a cutting instrument, and cutting instruments in gynaecology fail quietly. Nobody reports a blunt punch. What happens instead is that the pathologist starts writing “marked crush artefact” and “epithelium not assessable”, and three months later somebody wonders why the inadequate-sample rate has drifted up.

A dull jaw does not cut tissue. It compresses it, tears it, and pulls it. The epithelial architecture the pathologist needs to grade dysplasia is precisely what compression destroys.

Three practical controls:

• Test on a proxy, not on a patient. A properly sharp punch will cleanly cut two layers of thin latex or a folded piece of chamois with no drag and no tail.
• Track the inadequate-sample rate by tray, not just by clinician. A rising rate on one set is an instrument problem until proven otherwise.
• Set a service interval. Cutting edges are consumable. Send them out for professional resharpening rather than waiting for failure, in the same way you would with scissors and rongeurs.

Materials and Construction

Cervical biopsy forceps are made from martensitic stainless steel, normally AISI 420, hardened through the jaw to roughly 48–52 HRC. That range is the compromise: soft enough not to chip a fine edge on the opposing blade, hard enough to hold an edge through repeated reprocessing cycles. Shanks and handles are frequently AISI 410, which is tougher and less brittle but will not hold a cutting edge.

Ask for a satin or matt finish rather than a mirror polish. Colposcopy is done under a bright coaxial light source at magnification, and a mirror-finish shank throws glare straight back into the optics.

Passivation matters here more than the length of the instrument. The jaws sit in blood and acetic acid, then go through an alkaline wash and a steam cycle. A properly formed chromium-oxide layer is what keeps that combination from pitting the cutting edge, and pitting on a cutting edge is not cosmetic — it is the beginning of the crush-artefact problem described above. Our guide to instrument passivation covers what to require from a supplier.

Reprocessing Notes

1. Do not let the load dry. Cervical mucus and blood set hard in a basket jaw and in the spring housing.
2. Open the jaw fully before immersion, and brush the inner faces of the cup manually. Ultrasonic cavitation alone does not reliably clear a Tischler basket.
3. Flush the spring mechanism. Debris in the return spring is a common cause of sticky action that gets mistaken for a worn instrument.
4. Lubricate the hinge with a water-soluble instrument lubricant before sterilisation, not a mineral oil.
5. Steam sterilise at 134 °C, jaws open, not stacked under load.
6. Inspect the cutting edge under magnification at each reassembly, not annually.

Choosing for a New Clinic

If you are equipping a colposcopy service from scratch, the pragmatic answer is two Tischlers and one Baby Tischler per tray, with a Kevorkian-Young available for the awkward lateral lesion and a Schubert only if your pathology service specifically asks for wedge orientation.

Buy more of them than you think you need. The constraint on a colposcopy list is not the colposcope; it is how many sharp punches are through decontamination and back on the shelf. A clinic running four biopsies a session on two instruments is running one instrument permanently at the wrong end of its sharpness curve.

Sourcing

Fizza Surgical manufactures cervical biopsy forceps in Tischler, Baby Tischler, Kevorkian-Young and Schubert patterns in Sialkot, under ISO 13485 with CE marking against EU MDR. Jaws are AISI 420 hardened and passivated, supplied satin-finished for use under coaxial illumination. See the full surgical instrument range, and our related guides to vaginal speculum selection and biopsy punch instruments. Regulatory documentation is on our certifications page.