Terrapon APR, Zattra CM, Voglis S, et al. Adverse events in neurosurgery: the novel therapy-disability-neurology grade. Neurosurgery. 2021;89(2):236-245.

Gómez Vecchio T, Corell A, Buvarp D, Rydén I, Smits A, Jakola AS. Classification of adverse events following surgery in patients with diffuse lower-grade gliomas. Front Oncol. 2021;11:792878.

Li H, Zheng D, Wang Y, et al. Decision-making tree for surgical treatment in meningioma: a geriatric cohort study. Neurosurg Rev. 2023;46(1):196. doi:10.1007/s10143-023-02103-3 doi:10.1038/s41598-025-21065-8

Leistner T, Terrapon APR, Hostettler IC, Bozinov O, Zeitlberger AM, Neidert MC. Adverse events in meningioma surgery classified using the therapy-disability-neurology (TDN) grading system. J Neurooncol. 2025;176(2):125.

Kälin V, Terrapon APR, Zeitlberger AM, et al. Assessment of Adverse Events Using the Therapy–Disability–Neurology (TDN) Grading System in a Cohort of Aneurysmal Subarachnoid Hemorrhage Patients: A Single-Center Retrospective Cohort Study. Brain Sci. 2026;16(6):599. doi:10.3390/brainsci16060599

Terrapon APR, Kälin V, Zeitlberger AM, et al. International survey-based assessment of the reliability, validity, and interpretability of the TDN grade for neurosurgical adverse events. Sci Rep. 2025;15(1):37600.

Dr. Alexis P. R. Terrapon

PD Dr. Marian C. Neidert

Therapy-Disability-Neurology (TDN) Grade

therapy

neuro

Classifies the severity of adverse events and/or complications based on the associated therapy, disability, and neurological deficits, initially developed for neurosurgery.

Neurosurgery adverse events classification.

TDN Grade

The Therapy-Disability-Neurology (TDN) Grade classifies severity of adverse events after neurosurgery.

Therapy-Disability-Neurology (TDN) Grade Calculator

Describes the severity of adverse hematologic and lymphatic events from cancer treatment.

CTCAE

Assesses disability in patients with neck pain.

Predicts tracheostomy need in neurocritical care patients.

SETscore

The American Academy of Pediatrics (AAP) focuses on the health, safety, and well-being of infants, children, and young adults. With about 67,000 members, including pediatricians, medical subspecialists, and surgical specialists, the AAP supports optimal care. Over 45,000 members are board-certified Fellows of the AAP (FAAP). Its mission is to promote children's health and well-being while supporting members' professional needs.

American Academy of Pediatrics (AAP)

The American Association for Physician Leadership&reg; (AAPL) is the world&rsquo;s oldest and largest professional association dedicated solely to maximizing physician leadership.&nbsp;From the moment physicians begin their leadership journey through the time they are seasoned leaders, AAPL provides education and training, resources and tools, and content and experiences needed to close gaps between hands-on clinical care, organization system improvements and optimized business outcomes.

American Association for Physician Leadership (AAPL)

American Association for the Study of Liver Diseases

The American College of Emergency Physicians (ACEP) represents more than 38,000 emergency physicians, emergency medicine residents and medical students. ACEP promotes the highest quality of emergency care and is the leading advocate for emergency physicians and their patients, and the public. Members may earn up to 850 continuing medical education hours every year through ACEP&rsquo;s robust catalog of peer-reviewed publications and on-demand courses presented by world-renowned emergency medicine experts.

American College Of Emergency Physicians

The American College of Gastroenterology (ACG) supports clinicians in delivering high-quality, evidence-based care to gastroenterology patients. Its mission is to advance care for those with gastrointestinal disorders through excellence, innovation, and advocacy. ACG provides members with up-to-date scientific information through annual meetings, the American Journal of Gastroenterology, training courses, and research grants, focusing on digestive health and GI disorder treatments.

American College of Gastroenterology

American College of Rheumatology

The American Gastroenterological Association (AGA), founded in 1897, provides leadership and education to over 16,000 members worldwide, all dedicated to advancing gastroenterology. The AGA&rsquo;s mission is to empower clinicians and researchers to improve digestive health through clinical guidance, practice resources, and peer-reviewed research. Key journals include Gastroenterology, Clinical Gastroenterology and Hepatology, Cellular and Molecular Gastroenterology and Hepatology, and others.

American Gastroenterological Association

American Heart Association

American Society of Clinical Oncology

American Urological Association

EB Medicine is the premier provider of evidence-based clinical content and CME resources for emergency medicine practitioners.

EB Medicine

MDCalc Blog

MDCalc CME

Postgraduate Institute for Medicine

The Rome Foundation is a nonprofit organization dedicated to advancing the diagnosis and treatment of Disorders of Gut-Brain Interaction (DGBI), also known as functional gastrointestinal disorders. Its mission is to improve the lives of people with DGBI. For over 30 years, the Rome Foundation has worked with scientists and clinicians worldwide to classify and assess GI function and dysfunction, creating symptom-based criteria used in clinical trials and daily practice to guide diagnosis and treatment.

The ROME Foundation

Listen to the VACO co-creators break down how to use VACO, what it does, and what it doesn’t.