Scissors

Metzenbaum or Mayo? It is the blade-to-shank ratio

The two most-used scissors in general surgery, and the confusion between them costs money.

A Metzenbaum has short blades on a long shank. That ratio is what makes it a dissecting scissor - the long shank reaches depth, the short blades open tissue planes with control, and the whole instrument is built light.

A Mayo has longer, heavier blades on a shorter shank. It is built to cut through substantial tissue and suture, and it cuts partly by mass.

Using a Metzenbaum to cut suture is the single most common way a good scissor is ruined. Suture is harder than the tissue a Metzenbaum's fine edge is ground for; a few cuts dull it, and a dull dissecting scissor chews planes instead of opening them. Keep a Mayo on the tray for suture and the Metzenbaum lasts years longer.

Iris scissors, and why there are so many

Iris scissors are short, fine and sharp-tipped - originally ophthalmic, now used anywhere delicate cutting is needed close to the surface. They appear here in straight, curved and angled forms, in supercut and tungsten carbide, in large-ring and standard handles.

The number to read is the length: an 11cm iris works in the fingertips at the surface, and anything longer is a different instrument for a different depth.

Curved, straight, or angled

Not a preference - each solves a different geometry problem.

Straight blades cut along the line of sight. Right for suture, dressings, and cutting towards yourself on a flat field.

Curved blades let the tip follow a plane that curves away, and let the surgeon see past the blade to the tissue beyond it. Most dissection is done curved for this reason.

Angled - the Potts-Smith range at 25°, 45° and 60° - puts the blade at an angle to the shank so it can enter a vessel lying across the working line. On an arteriotomy the angle is what keeps the surgeon's hand out of the view.

Tungsten carbide and supercut: two different upgrades

These get conflated and they solve unrelated problems.

Tungsten carbide means the cutting inserts are a harder material than the instrument body, usually marked with gold rings. The edge lasts substantially longer. That is all it does.

Supercut means one of the two blades carries a micro-serrated edge that stops tissue sliding forward ahead of the cut. It buys control on slippery, elastic tissue - not sharpness. An instrument can be either, both, or neither; see Super Cut Scissors for the detail, including why a supercut edge cannot be resharpened conventionally.

Frequently asked

Which scissors for suture? Mayo, or a dedicated stitch scissor - Spencer or Littauer. Not a Metzenbaum, not an Iris.

What are the gold rings? By convention, gold handles mark tungsten-carbide inserts and black handles mark supercut. It is a convention rather than a standard, so confirm against the catalogue number on a mixed tray.

Can these be resharpened? Conventional edges, yes, many times. Supercut edges need the original serration geometry restored, which most general services cannot do - they hone the serrated blade flat and the instrument quietly stops gripping.

What length do I need? Length follows depth of field, not the size of what you are cutting. Surface work takes 11-14cm; a deep pelvic or thoracic field needs 20cm or more.

Related collections

See also Super Cut Scissors, Surgical Knives & Knife Handles, General Surgery Instruments, Cardiothoracic Instruments and Needle Holders.

Other cutting instruments: Rib Shears, Wire Cutters & Nippers, Orthodontic Cutters, Dissectors, Dermal Instruments, Ophthalmic Instruments and Plastic Surgery.