Multisession SRS treatment of vestibular schwannomas results in an excellent rate of tumor control. The hearing, trigeminal nerve, and facial nerve function preservation rates reported here are promising.

The standard approach for sectioning of the filum terminale for a tethered spinal cord can be achieved via a limited S₁ exposure. This is performed with the commonly believed idea that the filum fuses with the dura at S₂. We dissected 27 cadavers to exclusively look at the level at which the filum pierces/fuses with the dura and also the level at which the dural sac ends. Most of the fila fused at S₂ with a range from L₅ to S₃. The majority of dural sacs ended at S₂ with a range from S₁ to S₃. However, 15% of the fila (4 of 27) fused above the S₁ level. In addition, 11% of the fila (3 of 27) fused off the midline. We hope that this anatomical information may be useful for neurosurgeons when standard approaches fail to identify the filum at its usual level and location.

Larger cochlear volume is associated with lower risk of hearing loss following trisession SRS for vestibular schwannoma. Controlling for this phenomenon, higher radiation dose and larger irradiated cochlear volume are significantly associated with higher risk of hearing loss. This study confirms and quantifies the risk of hearing loss following trisession SRS for vestibular schwannoma.