In 1934 at the University of Basel under Eugen Ludwig, Josef Klingler developed a new method of dissection based on a freezing technique for brain tissue that eloquently revealed the white matter tracts.
In 1908 the first successful lumbar discectomy was initiated and performed by the German neurologist Heinrich Oppenheim (1858-1919) and the surgeon Fedor Krause (1857-1937); however, neither recognized the true pathological condition of discogenic nerve compression syndrome. With the landmark report in The New England Journal of Medicine in 1934, the two American surgeons William Jason Mixter (1880-1958) and Joseph Seaton Barr (1901-1963) finally clarified the pathomechanism of lumbar disc herniation and furthermore, propagated discectomy as the standard therapy.
Walter Edward Dandy is credited with the first accurate diagnosis and successful removal of a Brainstem cavernous malformation in 1934, but few cases were documented in the following decades because neurosurgeons considered intervention too dangerous 1).
In Germany various surgeons performed individual cranial operations before the 1870s, and neurosurgery evolved as a distinct discipline in Germany around 1934 2).
Torkildsen A. The Gross Anatomy of the Lateral Ventricles. J Anat. 1934 Jul;68(Pt 4):480-91. PubMed PMID: 17104497; PubMed Central PMCID: PMC1249003 3).