A quick look at the literature suggests the correct name should be Macrodiplodiopsis desmazieri.
The original name Sphaeria platani Ces., 1854 was illegitimate, and so when treated in Splanchonema the correct name for that fungus is the replacement name S. platanti Barr, 1984.
Hendersonia desmazieri Mont., 1849 has been generally considered to be the asexual form of the same fungus. That is now known as Macrodiplodiopsis desmazieri and if the two are considered synonyms it provides the earliest epithet for the taxon. It was argued at one point that they refer to different species. However, more recently an epitype was selected for M. desmazieri to pin it down. That epitype was from the sexual morph and produced a splanchnonema anamorph in culture. There are other sequences deposited as S. platani that are very close (although not identical). I guess somebody could come along and decide S. platani is still a different but related species, and then they would need to declare an epitype and create the combination Macrodiplodiopsis platani based on Barr's replacement name. I don't think anybody would do that without good reason.
An outstanding issue is that the generic name Splanchonema has not been pinned down because the type species, Splanchnonema pustulatum, has not been sequenced. It is conceivable that Splanchonema might prove to be an earlier generic name than Macrodiplodiopsis, and thus the correct name would be become S. desmazieri. But that is work to be done.
That is my reading of the current situation.

That currently still leaves M. desmazieri as the correct name and S. platani as a synonym. The Macrodiplodia name is already added to iNat,