History
Early descriptions
In 1777, Eduard Sandifort of Leiden, the Netherlands, wrote a postmortem first description of a vestibular schwannoma. He observed "a certain hard body adherent to the auditory nerve," and concluded this cause of deafness was beyond the reach of medication or surgery and was therefore incurable. The Schwann cells that multiply to form a VS on the vestibulocochlear nerve were identified 60 years later in 1838 by the German physiologist Theodor Schwann, the co-founder with the botanist Matthias Schleiden of the critically important cell theory that all living things are composed of cells. In 1895, Thomas Annandale, a general surgeon at the Royal Infirmary in Edinburgh, Scotland, was the first to successfully localize and surgically remove a VS. His achievement was exceptional. Finger dissection of VS to shell out the tumor was typical. The main goal when dealing with large tumors was preservation of life. Early surgeries
In the early 1900s the mortality rate for VS surgery was in the range of 75 to 85%. Surgeons typically delayed invasive intervention as long as possible as a last resort. Harvey Cushing (1869–1939) is known as the father of neurosurgery for VS. His basic study published in 1917 was entitled Tumors of the Nervus Acusticus and the Syndrome of the Cerebellopontine Angle. Cushing perfected the retrosigmoid surgical approach, and by doing suboccipital craniotomy and subtotal removals he was able to reduce mortality to 4% by 1931. Cushing worked at Brigham Hospital in Boston.
As space-occupying-lesions, the tumors can reach 3 to 4 cm or more in size and infringe on the facial nerve (facial expression) and trigeminal nerve (facial sensation). Advanced hearing loss and spells of true vertigo may occur. Very large tumors are life-threatening when they press on the cerebellum or cause brainstem compression. Late symptoms of very large VS include headache, nausea, vomiting, sleepiness, mental confusion and eventually coma. Neurofibromatosis Type 2 (NF2)
For the most part, unilateral sporadic vestibular schwannomas are readily treated successfully by modern medical techniques. Having bilateral VSs is a more troublesome condition. Bilateralism is considered to be the hallmark and main diagnostic criterion of Neurofibromatosis Type II (NF2), a genetic disorder that is heritable, progressive, difficult to manage, and has a 1 in 2 chance of being passed on to each offspring. NF2 patients tend to have a more severe mutation, although there are mild mosaic cases in which only some cells carry the mutation. Genetic testing confirming mutation of the NF2 gene is recommended. About 50% of people with NF2 have a de novo mutation, and about 50% of these new mutations will be mild mosaic cases which are less likely to be passed on. NF2 patients may develop other cranial and spine tumors. NF2 develops during the teens or early adulthood, whereas sporadic VSs are diagnosed mostly in patients between the ages of 40–60 years. Both varieties of VS (sporadic and NF2) are very rare, accounting for only about 8% of all primary brain tumors.