In a number of suttas, mainly in the Majjhima, we encounter a kind of physician called a sallakatta. This is usually combined with bhisakka, “healer, doctor”. In MN 63, MN 101, and MN 105 this doctor is called upon to extract an arrow (salla). This term has been previously discussed by Jayarava, but only in the context of MN 63.
Elsewhere in the EBTs (with one exception, see below) the term is used either in a list of various medical specialists (DN 2, etc.) or as a spiritual epithet. In neither case can we infer anything about the kind of specialty they practice.
It would seem likely that it is no coincidence that the specialist’s descriptor refers to an arrow or dart. However, in Pali translations it has typically been translated as “surgeon”. This seems insufficiently specialized. I am not sure, but it seems this reading implies the compound is resolved “applier of the blade”, reading katta from kar, “to do”. However, the Sanskrit term is śalyakarttṛ, or perhaps śalyahartṛ, which seems better attested. But both these terms have a similar sense, to “cut”, not “do”. This agrees with the commentarial gloss, sallakantana. Monier Williams gives the sense “‘cutter or remover of splinters’, a surgeon” for śalyakarttṛ. This isn’t entirely satisfactory, however, as a surgeon generally is not a specialist in removing darts.
The basic sense would therefore seem to be an “arrow extracting doctor”. It seems like an odd medical specialty, but there we are. Perhaps it began as a military doctor, a field surgeon for treating battlefield wounds. This is supported by the commentarial gloss, which says the man was struck by an opposing army (parasenāya ṭhitena viddho bhaveyya). So maybe we should, in fact, translate as “field surgeon”. Presumably such doctors would ply their trade in times of peace as well.
This is complicated, however, because in the Milinda the bhisakka sallakatta is applied in a variety of settings, including “easing a disease with medicine” (Mil 3.1.3), treating someone with “multiple afflictions” (Mil 6.1.5), and so on. Clearly the sense “arrow extractor” is inadequate here.
Given that the early use is mostly consistent, and the later use is much broader, perhaps what we are witnessing is an unwarranted generalization based on the early sutta passages. These similes, of the man struck by an arrow, were very famous, and perhaps they simply entered the Pali lexicon from there.
If this is the case, it is further possible that this process had already begun during the compilation of MN. For in MN 75, bhisakka sallakatta is used for a doctor who treats a leper, with no arrow in sight. So it seems that we should either find a new explanation for the term, or accept that this semantic drift was underway during the compilation of MN.
So I would suggest that sallakatta means a physician who specialized in battlefield wounds, especially for treating soldiers struck by arrows. As such specialists moved among the general populace, the term became applied more generally, a process probably facilitated in the Pali (and later Buddhist literature) by the somewhat automatic echoing of the well-known early idioms from the Majjhima. I would therefore suggest translating either as “arrow extracting doctor” if literalness is desired, or “field surgeon” for more idiomatic general use.