Neurofibromatosis

Neurofibromatosis Type 2 is a genetic condition that results in people having a predisposition to benign tumours of the nerves and ‘linings’ of the central nervous system and in their brain. These non-malignant tumours can be life threatening due to their rate of growth and location. Schwannomas can grow on cranial, spinal root and peripheral nerves; meningioma and ependymomas also occur. Vestibular schwannomas (acoustic neuromas) are a particular problem because they affect the auditory nerve.
Preservation of hearing, avoidance of disability and facial palsy from surgery and maximising life expectancy are the key aims for treatment.

Challenge for rare disease

There was emerging evidence on the different approaches to treatment – surgery (which can lead to loss of hearing) versus a policy of ‘watch and wait’ with careful monitoring of tumour growth.

Network

The national network was formed of four expert centres, as a hub-spoke model with satellite clinics and stereotactic radiosurgery provided at regional hospitals.
The network of centres met on an annual basis to share agreed clinical outcomes at an annual Peer Learning Workshop, presenting outcomes in a standardised format to enable comparison. The Peer Learning Workshop was structured around three areas to enable learning:

1. Sharing of agree clinical outcomes and profiled against case mix
2. Discussion of rare or complex cases
3. Presentation of new and emerging evidence, audit results

The Peer Review Learning Workshops enable clinical leads to identify new emerging best practice, innovation and development of surgical and treatment philosophies.

Clinical Outcomes

• Length of time that useful hearing, as measured by speech discrimination, is maintained in at least one ear from date of diagnosis. (Speech discrimination of >60%)
• Facial palsy rates of <20%, as measured by House Brackmann scores of 4-6, 18 months post surgery for vestibular schwannoma – Proportion of full time users of an Auditory Brain Stem Implant or cochlear implant of those who would otherwise have no useful hearing. Expected that >80% will be full time users
• Reduction in disease related mortality
• Timing between presentation of symptoms and surgical intervention

Emerging best practice and innovation from peer learning

Patients experienced improvements to the outcomes of their treatment and surgery including:

• The development of surgical philosophy avoiding destructive neurosurgery wherever possible.
• The adoption of a cancer drug (Avastin) based on a small US publication, as a research protocol, found ‘faster growing’ vestibular schwannoma tumours responded most to treatment with Avastin due to the effect on blocking angiogenesis by inhibiting vascular endothelial growth factor A (VEGF-A)
• Following the research protocol, the network had the largest collection of scans from Avastin patients and the service was able to assess the impact Avastin had on meningioma and ependymomas.
• Adoption of ‘head-wrapping’ for patients with a cochlear implant for an MRI scan, which stop patients from having surgery to remove CI batteries.
• Evidence emerged that a cochlear implant on a damaged cochlear nerve, has a poor hearing outcome, but was better than the more expensive auditory brainstem implant.