A 16-year-old girl from Warrington has become the youngest known person in the world to undergo awake brain surgery for a rare and potentially fatal brain condition.
Matilda, known as "Tilly", underwent the groundbreaking operation at Alder Hey Children's Hospital after doctors discovered she had an arteriovenous malformation (AVM) - an abnormal tangle of blood vessels in her brain that could have ruptured without warning.
The procedure
The complex procedure, carried out in December 2025 when Tilly was 15, required surgeons to wake her during the operation so they could monitor her speech and brain function while removing the malformation. The surgery was the first of its kind to be performed at Alder Hey for an AVM.
Before the operation, Tilly had been suffering increasingly frequent seizures and said she felt like she was "living with a ticking time bomb".
She said: "I just wanted it out. The AVM was causing me to have frequent seizures and they were getting worse and I knew it could rupture at any point, which was really scary. I felt like my life was on hold."
Diagnosis and challenges
Tilly was diagnosed after an MRI scan following psychogenic non-epileptic seizures. Doctors found the AVM was positioned close to areas of the brain responsible for speech, movement and vision, making treatment particularly challenging.
Consultant paediatric neurosurgeon Conor Mallucci, who led the surgery alongside Vejay Vakharia, said operating on the malformation carried significant risks because it was located near critical areas of the brain.
He said: "The challenge for us is that it can be extremely difficult to differentiate between abnormal tissue and vital brain tissue, raising the risk of potentially damaging healthy brain tissue."
Awake craniotomy
Specialists decided an awake craniotomy offered Tilly the best chance of safely removing the AVM. During part of the 12-hour operation, she was brought round from the anaesthetic and asked to answer questions while neuropsychologists monitored her speech and language, allowing surgeons to identify and avoid damaging vital brain tissue.
Mr Vakharia said awake brain surgery is more commonly performed on adults and is only rarely considered for children because it relies on the patient remaining calm and cooperating throughout the procedure.
He said: "Because the procedure requires a lot of cooperation, it is not always offered to young patients but Tilly was so determined and so were we.
"While awake procedures have been performed on young patients for other neurological conditions like brain tumours, Tilly is among the youngest known individuals to undergo the surgery specifically for an AVM, which is extremely rare."
Recovery and outlook
The operation lasted more than 12 hours and Tilly was discharged from hospital just a week later. Follow-up scans have confirmed the AVM has been successfully treated, while doctors say she has experienced a significant reduction in her seizures.
Now 16, Tilly says she finally feels she has her life back.
She said: "Before the surgery, it felt like I was always worrying about what might happen.
"I've just finished my GCSEs and I can look forward to spending time with my friends, family, my dogs, enjoying the summer holidays and just getting on with being a normal teenager again. I'm so grateful to everyone who looked after me."
Tilly's mum, Clare, said: "This has been an incredibly difficult period for us all, especially Tilly. She has navigated things no child should have to but has shown such strength and resilience.
"I know her future looks bright thanks to Alder Hey. The care Tilly has received has been second to none. Everyone has been so kind, helpful and caring."
