15-year-old Matilda (Tilly) is the youngest person in the world to undergo awake brain surgery for an Arteriovenous Malformation (AVM).
The operation, performed at Alder Hey for the first time, required her to be conscious for part of the procedure so surgeons could safely treat the abnormal tangle of blood vessels in her brain that were at risk of rupturing at any time.
Tilly, from Warrington, underwent a complex procedure to treat an Arteriovenous Malformation (AVM), an abnormal tangle of blood vessels in the brain that can rupture without warning. The pioneering operation required her to be woken during surgery so specialists could safely remove the malformation while protecting vital brain function, the first time this procedure had been performed at Alder Hey and the youngest person in the world with the condition.
The surgery, which took place in December 2025, successfully treated the AVM, and Tilly continues to make a strong recovery.
I felt like it was a ticking time bomb in my brain and I just wanted it out. The AVM was causing me to have 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.” Tilly.
Tilly was diagnosed with an AVM following an MRI scan after experiencing psychogenic non-epileptic seizures.
AVMs are rare but serious conditions where arteries and veins become tangled, disrupting normal blood flow. If they rupture, they can cause stroke, brain damage and can be fatal.
Tilly’s AVM was located close to areas of the brain responsible for speech, movement and vision, making treatment particularly high-risk.
Consultant Paediatric Neurosurgeon Mr Conor Mallucci led the surgery alongside Mr Vejay N. Vakharia.
When an Arteriovenous Malformation (AVM) is located close to a critical area of the brain, treatment becomes far more complex. These regions control essential functions such as movement, speech and vision and are known as eloquent areas of the brain. In Tilly’s case, the AVM was located near the left side of her brain and close to several of these critical functions, which made surgery particularly high-risk. 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.”Consultant Paediatric Neurosurgeon Mr Conor Mallucci.
Standard treatments for AVMs can include minimally invasive procedures, surgery or radiosurgery. However, due to Tilly’s AVM’s location, these options carried an increased risk and could take years to work, and Tilly was already struggling with school and daily life.
After careful consideration, specialists at Alder Hey recommended an awake craniotomy, which is a highly specialised procedure rarely performed on children. During part of the operation, Tilly was woken so clinicians could monitor her speech and responses, allowing surgeons to precisely identify and protect vital areas of the brain.
In some neurosurgeries, patients are woken up during surgery and asked to answer simple questions for a short time before being put back to sleep while the surgeon continues to work. This allows us to treat as much abnormal tissue as possible while protecting the critical areas of the brain and is known as brain mapping. Awake surgery allows for greater precision and better long-term results but is not suitable for everyone.” Mr Vejay N. Vakharia.
Tilly was fully involved in the decision-making and decided to go ahead with this option in December 2025.
The procedure marked the first time this specific anaesthetic and surgical approach has been carried out at Alder Hey.
The surgery lasted over 12 hours, and Tilly was discharged just one week later. Follow-up scans have confirmed that the AVM has been successfully treated.
For Tilly and her family, the decision has been life-changing.
I still find it hard to recall some words and things like texting can be difficult but hopefully that will come with time. I’ve got my life back- I love spending time with my friends and our dogs. I feel like I can live my life to the very fullest now.” Tilly.
Tilly’s mum, Clare, is also thankful to the Alder Hey team.
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.” Clare (Tilly’s mum)
Supporting Quotes
Mr Vejay N Vakharia 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.”
Mr James Masters (pictured above), one of the lead Consultant Paediatric Anaesthetists alongside Dr Rishi Diwan, said: “There were a lot of challenges for us as anaesthetists. Firstly, we needed to make sure that Tilly was fully prepared both physically and psychologically to be woken during the procedure. This is a more common procedure in adults who are generally better able to understand and cooperate than most children. We had to carefully plan what medicines we could use that would strike the right balance between keeping her calm, comfortable and pain free but alert enough to respond to questions, which is a challenging combination. The brain doesn’t feel pain, but the skull and skin do, so she also required painkillers and local anaesthetic on board to numb the pain and help her tolerate that period of being awake.
“We also had to take out her breathing tube before waking her up, which was tricky due to her position and having an open wound. We modified her anaesthetic so that she was awake enough to communicate and almost immediately she was coherent and aware of her surroundings. I asked her: ‘Tilly do you know where you are’ and she replied ‘yes I’m in the operating theatre’ and then the neuro psychologists took over. Once they had finished their assessments, which took about half an hour, Tilly was anaesthetised again, we put the breathing tube back in and she went to sleep quite quickly while the operation continued. Once complete, Tilly woke up in recovery as normal.”
Dr Cathy Grant (pictured above) and Dr Stewart Rust, Consultant Clinical Psychologists, joined the surgery immediately before Tilly was woken up. Cathy said: “Tilly worked with me prior to surgery to develop her understanding of the tasks we would use to monitor her language function. During awake surgery, neuro-psychologists are listening out for any disruptions to language function associated with brain stimulation so that the area can be flagged as vital tissue by the neurosurgeons. Our role during awake surgery is also to help Tilly stay calm, engaged, and responsive so the surgical team can operate as safely and precisely as possible. Tilly was calm and she responded well to our questions. She engaged in a picture naming task and took it in her stride when stimulation halted her ability to name objects. It was such a pleasure to see her manage the procedure so well.”
Consultant Neurosurgeon Mr Jonathan Ellenbogen added: “Tilly has experienced only one seizure in the 12 weeks following surgery, which is a significant reduction from her pre-operative seizure frequency. We hope that removal of the AVM will help control this in the long term.”