The Russian-language Wikipedia (ru.wikipedia.org) lists two towns named Vydumka in the area you suggest. Both are in what is now the Zhitomir oblast (area) of Ukraine. They were founded in 1846 and 1930, so perhaps the older one is more likely. It's in the Korostyshev rayon (region) and only had 31 inhabitants in 2001. its coordinates are 50/13E, 29/11N, which you can copy and paste into Google Maps. Brusilov is about 15 miles east and slightly north of this Vydumka.

Alan Shuchat
Newton, MA

SHUCHAT (Talnoye, Simferopol, Sevastopol, Odessa, Balta (Abazovka),
Tavrig, Pogrebishche)
VINOKUR (Talnoye), KURIS (Mogilev-Podolskiy, Ataki, Berdichev)
SILVERMAN (Soroki, Kremenets), BIRNBAUM (Kamenets-Podolskiy)
KITAIGORODSKI (Zvenigorodka)