The chainsaw was originally invented for childbirth. In the 1780s, two Scottish doctors independently designed a small, hand-cranked chain saw to cut through pelvic bone during difficult deliveries. The tool bore almost no resemblance to the massive gas-powered machines used in forestry today, but the core mechanism, a toothed chain moving along a guide, is the same concept that eventually made its way into the timber industry over a century later.
The Surgical Problem It Solved
Before cesarean sections became safe and routine, a obstructed labor could be fatal for both mother and baby. One option surgeons had was a procedure called symphysiotomy: cutting through the cartilage and bone of the pubic joint to widen the pelvis enough for the baby to pass through. In the late 18th century, doctors performed this procedure with knives and hand saws, which were slow, imprecise, and caused significant trauma to surrounding tissue.
Around 1783 to 1785, Scottish doctor John Aitken designed a fine serrated chain that cut on its inner (concave) edge, powered by a hand crank. He illustrated it in his 1785 textbook on midwifery and used it in his dissecting room. Around the same time, fellow Scottish surgeon James Jeffray independently came up with the same idea, though he wasn’t able to have a working version produced until 1790. Jeffray argued that the chain saw allowed a smaller wound and better protected the nerves and blood vessels near the cutting site. Obstetricians at the time considered it a major improvement over the knives and straight saws they had been using.
How the Original Chainsaw Worked
The design was modeled on a watch chain. Small, sharp teeth were set along linked segments, and a hand crank drove the chain in a loop. It was a handheld instrument, nothing like the bulky machines that came later. A surgeon would wrap or position the chain around the bone that needed cutting, then turn the crank to draw the teeth through.
Beyond childbirth, the chain saw was also used for excision of diseased bone in joints like the knee and elbow. Jeffray specifically promoted it for this purpose, and other surgeons adopted the technique for removing infected or damaged sections of bone with less collateral damage than traditional tools allowed.
Heine’s Osteotome: The Next Step
In the 1830s, German surgeon Bernhard Heine refined the concept into a more sophisticated instrument called the osteotome. His version looked even more like a miniature chainsaw: a toothed chain driven around a guide blade, with configurable guards that minimized the cutting surface and protected soft tissue. Surgeons could use it for bone resections and even to cut openings in the skull without leaving bone splinters or damaging the brain underneath. This mattered enormously at a time when anesthesia was rarely available. Cutting through bone quickly, without repeated blows from a hammer and chisel, reduced the duration of what was already an agonizing experience.
The osteotome required considerable skill, and few surgeons could wield it as effectively as Heine himself. Still, it represented a clear line of evolution from Aitken and Jeffray’s original chain saw toward the mechanical cutting tools that would eventually leave the operating room entirely.
From Operating Rooms to Forests
The chainsaw didn’t enter the logging industry until the early 20th century, more than 130 years after its medical debut. In 1926, German engineer Andreas Stihl patented the first electric chainsaw to enter mass production. It weighed 116 pounds, requiring two people to operate, and was a far cry from the portable saws loggers use today. The following year, in 1927, the German company Dolmar developed the first gasoline-powered chainsaw.
Through the 1930s, Stihl shifted to gasoline-powered models that proved far more practical for fieldwork since they didn’t need an electrical connection. These early gas saws were still enormously heavy, but they established the template for the modern chainsaw: a self-contained, portable, engine-driven cutting tool. Over the following decades, engineering improvements steadily reduced the weight and increased the power until one-person operation became standard.
What Replaced the Medical Chainsaw
As surgical technique advanced, symphysiotomy fell out of favor in most of the world, replaced by the cesarean section once it could be performed safely with proper anesthesia and sterile conditions. The chain saw’s role in bone surgery was largely taken over by newer instruments. In 1894, Italian surgeon Leonardo Gigli invented a flexible wire saw originally designed for a variation of the same pelvic procedure. His saw turned out to be even more useful for cutting openings in the skull, and it remains part of neurosurgical instrument sets today, more than a century later.
So while the original chainsaw concept disappeared from delivery rooms, its descendants persisted in surgery in simplified forms. The version that became world-famous, though, was the one that traded bone for timber and a hand crank for a gasoline engine.