The medieval candidate for surgery could be described with four Ms: Male, military, moneyed, and mangled.
Most surgery developed around the war games that gradually grew more rule-bound and civilized but never ceased to be nearly as deadly as real war. Tournaments had one great life-saving advantage over war: a refereed time-out. There were lots of reasons why surgery didn’t happen on battlefields, and they’re too depressing to go into. But on a tournament field, conditions were perfect: everyone was rich, fighting was voluntary, and they could plan ahead for casualties.
The medieval surgeon’s bag contained some very sharp knives, a probe for examining wounds, and a cup to drain infections. Additionally, he carried silk thread and a needle, a short silver tube, and an iron instrument for cauterizing a wound (we might also call it a small branding iron).
The silver pipe was for removing barbed arrows, though these were more of a battlefield hazard than a tournament one. Removing a barbed arrow by pressing the pipe into the wound, enclosing the barbs in metal, was perhaps the simplest medieval surgery.
Silk thread was for stitching up ugly gashes, including trying to tuck intestines back into place. Abdominal wounds like that were among the serious wounds that had a *possibility* of successful surgery. Dirt had to be cleaned off the tissues, and after the wound was stitched, they learned that they needed to leave a drain hole for a while. (I’ll be keeping my eyes open for what they used as a drain tube in the days before latex or plastic. Will let you know if I find.)
Infections were a huge problem. One medieval theory held that the infectious wound was self-cleaning, so it should be kept warm and encouraged to swell and ooze. Another common practice was to use wine as a disinfectant.
At tournaments, head wounds were extremely common. Surgeons often tried to save a knight’s life with a trephine hole, bored with the sharp knife or with a small drill. This drain relieved pressure on the brain as the wound healed. While many or most patients died anyway, there’s evidence from buried skulls that some survived long enough for the trephine hole to close up with new bone as the patient went on with life.
There were two known elective surgeries: for cataract and for bladder stones. The cataract surgery was done by traveling amateurs and while it helped immediately, it later led to complete blindness. Stones were most likely treated in a monastery, where medical care was superior. The idea was to position the stone closer to the surface, perhaps trapping it in a fold of skin, and then make a very small cut or scoop to remove it. This sounds pretty reasonable until you imagine positioning a stone in the bladder or urinary tract without an ultrasound.