[Intraoperative complications in neurosurgical patients operated on in a seated position (personal observations)].

Specific intraoperative complications are described which occur as a result of sitting position of the patients: herniation of the cerebellar tonsils into the great occipital foramen in a case of tumour in cerebellar hemisphere and venous air embolism in another case of tumour in the cervical part of the vertebral canal. Attention is called to certain methods of prevention and diagnosis.