Therapy-Disability-Neurology Grade

The most used adverse events grading systems in neurosurgery are based on the therapy used to counteract them. This is an important limitation, as some frequent adverse events such as new neurologic deficits may have dramatic consequences on quality of life but cannot be treated and are thus regarded as low-grade in solely therapy-based grading systems. For example, a severe hemiparesis following tumor resection is usually reported as a grade 1 complication. As a solution, the Therapy-Disability-Neurology grade (TDN) takes into account the therapy used to treat adveres events , as well as the associated neurologic deficits and resulting disability. The TDN Grade was already validated on two cohorts with a total of 6071 patients and an association between the classification and functional outcome as well as costs was shown. The classification scheme was already used in other studies and the grading system is increasingly used in various countries.