Today the majority of surgical operations in the NHS
require a scalpel for incisions and other operations. It is perhaps one of the
most important instruments a surgeon possesses yet to most of us it is nothing
more than just a sharp blade. A scalpel is typically a small, thin and very
sharp knife used predominantly for surgical operations and dissections. There
are two parts to any scalpel, the handle and the blade. In the past, various
sharp materials have been used for scalpel blades such as the obsidian blade (a
volcanic rock) and glass, however, the main material in use today is
martensitic stainless steel. In an interview I conducted with a general surgeon
from Kings College Hospital, I explored the various properties required for a
scalpel. Unsurprisingly, the ones which came up were weight, sharpness,
shininess and corrosion resistance. Corrosion resistance is a standard property
for any surgical instrument and a shiny blade allows the surgeon to see the
point at which he is cutting. A heavier scalpel gives the surgeon more control
but there must be a playoff between control and practicality when considering
what would make the ideal scalpel.
Stainless
steel – the material used for the blade of the scalpel – is an alloy, which is
a metal made by combining two or more different metals to enjoy superior
characteristics such as increased strength and corrosion resistance. There are
five different grades of stainless steel. Identifiable by their different
microstructures, they have different properties due to the balance of their
constituent elements e.g. Chromium gives varying resistance to corrosion,
nickel helps with ductility and increases the strength of the material, as does
carbon. Martensitic steels contain from 12 to 18% chromium, 2% nickel and about
1% carbon. Martensitic steels are chosen due to their adequate corrosion
resistance and ductility, which allows them to be shaped into the blades as
well as their strength after being quenched.
The scalpels used in NHS hospitals
are either disposable or reusable. The disposable ones are less common and are
only used in minor theatre whereas the reusable scalpels are used for large
scale operations in major theatre. The difference between the two is the
handle, although the size of the blade may also vary depending on the
requirements of the operation. Reusable scalpels have a stainless steel handle
whereas disposable scalpels have plastic handles. However, due to health and
safety issues, the blades of the reusable scalpels are never reused. The training
required and the potential for injuries in the cleaning blades means that it is
not only economically beneficial to buy new blades but also safer to do so. The
stainless steel handles are sterilised and reused.
The whole surgical process has evolved over the years and stainless steel scalpels seem to be where we are at now. However, it is widely believed that the future holds something very different for surgery. Femtosecond lasers are considered to be the most advanced form of carrying out surgery in the 21st Century. A femtosecond is one quadrillionth of a second (10-15seconds). Femtosecond lasers produce very brief, high-energy light pulses that can sear targeted tissue so quickly and accurately that the lasers’ heat has no time to escape and damage nearby healthy cells. It gives surgeons the ability to operate on a micron scale, which is why lasers are mainly used in eye surgery.
