The retrosigmoid approach is a surgical approach used in neurosurgery to access the posterior fossa of the brain through a small opening made behind the ear. This approach is commonly used for the resection of acoustic neuromas, meningiomas, and other tumors located in the cerebellar-pontine angle. The approach provides excellent access to structures in the posterior fossa while minimizing the risk of damaging critical structures such as the facial nerve and the cerebellum. It is considered a safe and effective technique for accessing and treating tumors in this region of the brain.