- Medical ninjutsu uses chakra and 1000 year outdated bio theories to get results similar to modern medicine. Weaker in some areas, stronger in others.
- Medical jutsu give better tools of observation than historic doctors had access to. Chakra weirdness adds degrees of freedom, makes empirical discovery more challenging, adds another organ system + bloodlines to the balance.
- Outdated bio theories. How much doctor ninjutsu is wasted on placebo or worse?
I think it's relatively unlikely that
ninjutsu is being wasted on placebo. From what we've seen, a lot of medical
procedures in MfD-world are based on inaccurate knowledge, as in the example below:
"I apologise for disturbing you, Lady Murasaki," he said, giving her his most charming smile. Fortunately, the woman was old enough to be his mother, so this did not quite provoke a homicidal response from Yuno. "I happen to be a medic-nin back home, and I was hoping you'd allow me to learn a little from the Isan medical tradition."
"Pfah," Murasaki snorted. "The last thing I need is some barbarian rushing into my treatment chamber, bringing bilious spirits and the viridian taint and oxygoblins into a purified environment. Now get out."
"Actually," Noburi said, "I performed the propitiating rites for bilious spirits before I came in, both the deosil and the widdershins versions. And I sprinkled salt on my heels to disgust the viridian taint." No one really believed in the viridian taint anymore, as it was well-established that brain shakes were caused by demonic possession. However, it had been safe to assume that Isan would be behind the curve when it came to medical theory. "I've never heard of oxygoblins before, though, so I'm sorry about that."
"Made those up," Murasaki grunted. "Fine. You can come in. Leave the cursed child at the door."
But what we've seen of medical ninjutsu makes it seem basically like using medical chakra to directly manipulate flesh, with chakra's own processing capacity handling the details of healing. The "mednin" stat doesn't seem to represent knowledge of a wide variety of medical jutsu, many of which are useless; instead, it seems mainly to represent skill with medical chakra, which acts as an endless toolbox for surgery, disinfection, etc.. That means there's probably limited scope for improvement in how the basic MedNin stat is used, without designing new and specialized medical techniques, because medical chakra probably doesn't have the control resolution for you to tell it "fix this person's genetic defect", even if you understand what DNA is, without a stupidly high MedNin that almost no one will actually have. (In particular, that
Oro probably doesn't have; even he only has so many high-level pyramid slots.)
- Magical herbs? Magical disease.
- Cadaver study.
- Not much study into the brain.
- No treatment for mental illness.
- On the other hand, biopuppets.
- Most pressure for scientific discovery is on treatments for traumatic combat injuries.
- Blunt trauma. Blood loss. Broken bones. Elemental burns + shocks.
- How does the healing work?
- Enhance natural recovery mechanisms of body?
- Stimulate pluripotent stem cells?
- Feedback loop of true bio knowledge and direct observation and adjustment of medical ninjutsu in action is potent. Huge gains over modern medicine on the table.
- Better study of medicinal pathways of effect.
SImilarly, I think this feedback loop is unlikely, primarily because I don't think MedNin has high enough resolution for improvements in understanding to really matter. Specific techniques that rely on it are absolutely something you could investigate, and I wouldn't be too surprised if it were possible to create e.g. an organism-wide DNA editing technique, if you understand what DNA is; but that's not knowledge that you'd get from just having a microscope. It would require a huge amount of biochemical research, and I don't think medical ninjutsu is likely to help very much with accelerating that. Remember that MS8 was considered revolutionary by Noburi for medical work; that puts limits on how detailed the diagnostics medical ninjutsu gives you can be.
- Microscopy radical enough to observe chromosomes cracks open bloodline research. Traces of the Sage's work.
- Microorganisms. Structure of cells. Cell specialization.
- Compare development of embryos with or without bloodlines.
- Orochimaru will not be distracted from bio studies forever.
- With a strong microscope, Noburi gets there first? Warns us of dangers ahead.
I'll give you this one; it's possible that people with certain bloodlines visibly have additional or altered chromosomes that would give an obvious starting point for understanding how bloodlines work. However, without the capacity to actually do genome mapping, I don't think Oro's likely to get very far researching that. Unlike in the real world, he can't use animal models because bloodlines are unique to humans and probably don't have anything in common with chakra beasts, and human generation times are far too long to do any kind of linkage mapping given the population sizes Oro has to work with; and as I said above, it would take a lot of hard biochemical work for him to get to the point of even understanding what DNA is, and I don't think medical ninjutsu is likely to help much with that. Remember, Oro probably doesnt even know what
atoms are; he'd have to get pretty far into chemistry before he could start on biochemistry, and we have no real reason to think he's done that.