Study aims to prevent blindness in patients with neurological condition

01 April 2021

A new clinical trial being led by the University of Birmingham and University Hospitals Birmingham NHS Foundation Trust (UHB) aims to identify the best surgical treatment option to prevent blindness in patients with a neurological condition.

Funded by almost £1.5 million from the National Institute for Health Research (NIHR), it is hoped the research will lead to changes in healthcare policy for the treatment of patients with Idiopathic intracranial hypertension (IIH).

Thus far, there is no known cause for the neurological condition, which increases intracranial pressure around the brain without the presence of tumour or disease.  Common symptoms of IIH, which is strongly associated with weight, include headaches, visual loss, pulsatile tinnitus, and back and neck pain. If left untreated, the disorder can lead to blindness.

The condition is managed with weight loss and medication, however, in severe cases that present as an emergency with decreasing vision, surgery is needed to prevent blindness.

Currently two different types of surgeries – dural venous sinus stenting (stenting) and cerebrospinal fluid (CSF) shunting – are used to prevent blindness, however there have been no clinical trials to determine which is the best operation.  The team will carry out a clinical trial involving up to 138 IIH patients with rapid vision deterioration to establish which of the surgical procedures is the best at saving vision; the safest with least complications; and the most cost effective.

The research, which has been developed in consultation with patient charity IIH UK, will be carried out by a team of experts the University of Birmingham, UHB, and at sites around the UK.

Alex Sinclair, Professor of Neurology at the University of Birmingham, Honorary Consultant Neurologist at UHB and Chief Investigator of the new research project, explained: “CFS shunting involves implanting a thin tube known as a shunt in the brain, which allows the excess cerebrospinal fluid flow to another part of the body, thus rapidly reducing brain pressure.

“However, within the first year of surgery many tubes become blocked or infected and stop working.  This, and other complications, have a significant impact on patients’ lives and have important cost implications for the NHS.

“More recently, stenting has been used, which involves placing a small stent across a narrowing of certain blood vessels in the brain, which can improve blood flow and lower brain pressure.”

Philip White, Professor of Interventional and Diagnostic Neuororadiology at the University of Newcastle and Co-Investigator, added: “So far, studies have not provided high quality evidence to show that this procedure can prevent blindness when vision is rapidly declining.

“Additionally, we need to confirm procedural durability compared with the surgery, which may need to be repeated and establish its safety is at least comparable.”

Miss Susan Mollan, Director of Ophthalmic Research at UHB and Co-Investigator, added: “We hope that the results of our study will provide evidence that will influence NHS policy and will lead to improved care for IIH patients, ensuring they receive the best possible treatment to prevent them from losing their eye sight.”

Amanda Denton, IIH UK Trustee and Research Representative, said: “IIH UK is delighted that this important trial is being carried out. Identifying the best types of intervention is one of our members’ top ten research priorities.

“Many of our members have shunts and stents to prevent them losing their sight and research to find the most effective method with the least complications is vital to improve their quality of life.”

The trial, will see participants being allocated to CSF shunting or stenting, which will be decided at random by a computer. The main outcome of the trial to be evaluated will be preservation of vision. A number of key additional outcomes, including treatment-related complications, headache and patient reported quality of life, will also be assessed.

Dr Ben Wakerley, Consultant Neurologist at UHB and Co-Investigator, comments: “The impact of these interventions on headache and quality of life have been highlighted to be of key importance by patients.”

An economic evaluation will be performed, led by Professor Emma Frew, University of Birmingham Co-Investigator, to estimate the cost-effectiveness of shunting versus stenting. Participants will be asked to attend routine hospital check-up visits over a year. Their health would then be monitored through linked NHS database records for longer-term follow up at two years.