immunosurgically

The story

1. Proto-Indo-European*mey-
2. Proto-Indo-European*moy-nós
3. Proto-Italic*moinos
4. Latinmūnus
5. Proto-Indo-European*né
6. Proto-Indo-European*n̥-
7. Proto-Italic*n̥-
8. Latinin-
9. Latinin- -is
10. Latinimmūnis
11. Middle Frenchimmun
12. Englishimmune
13. Englishimmuno-
14. Proto-Indo-European*ǵʰes-
15. Proto-Indo-European*ǵʰésōr
16. Proto-Hellenic*kʰéhər
17. Ancient Greekχείρ (kheír)
18. Proto-Indo-European*werǵ-
19. Proto-Indo-European*worǵós
20. Proto-Hellenic*worgós
21. Ancient Greekχειρουργός (kheirourgós)
22. Ancient Greekχειρουργῐκός (kheirourgĭkós)
23. Late Latinchīrurgicus
24. Proto-Indo-European*h₂el-
25. Proto-Indo-European*h₂élisder.?
26. Medieval Latincirurgicālis
27. Middle Frenchcirurgica
28. Middle Englishcirurgical
29. Englishsurgical
30. Englishimmunosurgical
31. Proto-Indo-European*leyg-
32. Proto-Germanic*līką
33. English todayimmunosurgically

From immunosurgical + -ly.