Treatment of small and medium-sized vestibular schwannoma—a need for better evidence

Excerpt

Medical and surgical practice is based on experience gained through individual clinical experience as well as evidence gained through studies of various kinds. Obtaining experience may be challenging; many neurosurgical procedures require training past residency and many neurosurgical disorders such as vestibular schwannoma are indeed rare. Evidence is graded at levels depending on study design. The hierarchy of blinded, randomized, prospective, and retrospective non-randomized studies is well known. Case series and expert opinion represents less robust evidence, but these types of publications are very common in the medical/surgical literature. When performing a study, one needs to define valid and reliable endpoints. For example, an early postoperative MRI scan showing complete tumor removal may be reliable, but less valid if the patient became incapacitated postoperatively. Patient-reported data using a standardized questionnaire may be highly valid, but unreliable if the attending surgeon assists the patient in filling it out. …