Neurosurgical Management of Complex Malignant Skull Base Lesions

I was awarded an HCA International Foundation Scholarship in 2015 to learn advanced neurosurgical techniques for treatment of poorly controlled neuropathic pain in the palliative patient group. The principal objective of the scholarship was to learn how to do cordotomies at the Vancouver General Hospital but, by very careful use of the scholarship monies, I managed to achieve more than expected. I visited two different units to learn surgical techniques for the control of neuropathic pain.


Background


The Functional Neurosurgical Service at Queen’s Hospital, Romford was established in 2008 and, at that time, was the newest out of 15 similar units in the United Kingdom. Its original remit was to establish a deep brain stimulation service for Essex. In the ensuing years, the unit has grown into the third most active functional neurosurgical service in London and the ninth in the UK. We now not only offer deep brain stimulation for movement disorders such as tremor, dystonia and Parkinson’s disease but also deep brain and motor cortex stimulation for pain, vagal nerve stimulation for epilepsy, resectional surgical procedures for epilepsy and the implantation of intrathecal pumps for spasticity and pain. During the same period, there has been a significant increase in the population of Northeast London and Essex and a corresponding rise in the number of cancer cases.

It has been estimated that almost all patients with disseminated cancer will experience pain at some stage. The pattern of pain depends on the type of tumour: breast and lung cancers tend to cause bone, chest and spinal pain, abdominal visceral cancers cause poorly defined abdominal pain and tumours involving the salivary glands are notorious for causing very severe, intractable facial pain. The majority of cases can be controlled with drugs. However, in approximately 2%of cases, drugs are either ineffective or are associated with severe side effects. In the Northeast London and Essex region, this equates to almost 1500 patients. Our oncologists (Queen’s Hospital) estimate that they encounter approximately 8 cancer patients per year with pain symptoms that defy conventional pharmacological treatments.

My aim was therefore to try to offer an alternative treatment to patients falling into this group. Pain neurosurgery seeks to surgically disrupt the neural pathways involved the transmission and perception of pain. We had previously shown that neurostimulatory procedures are effective in controlling neuropathic pain but the cost and the length of such procedures precludes its use in patients who are often frail and have a relatively short survival. Lesioning procedures are relatively cheap, fast, less taxing for the patient and very effective. However the effects wane after a year. Lesioning is therefore ideal in patients where the survival is expected to be less than 1 year.

Vancouver

The quintessential lesioning procedure for neuropathic pain is the cervical cordotomy. This can be performed as a open procedure or via the less invasive percutaneous technique. Cordotomies are particularly effective for unilateral chest and limb pain. At the present moment, there are only 3 units in the UK offering this service: Liverpool, Cosham and Oldham. The cordotomies are performed by pain specialists (not neurosurgeons) and by using an image intensifier. I arranged to go to the Vancouver General Hospital to learn how to do CT-guided cordotomies and my mentor was Professor Honey. I went to Canada in January 2016 for a 2 week period. During this time, I not only observed but was directly involved in the selection and the execution of the procedure. The results were significant and instantaneous. Patients who could hardly move before surgery due to pain could transfer from bed to trolley without help within minutes of a cordotomy.
Whilst there, I also learnt how to do trigeminal nucleotractomies. This procedure involves the creation of lesions within the spinal trigeminal nucleus. This procedure was extremely effective for pain in the head and neck region (areas not covered by a percutaneous cervical cordotomy). There are less than 5 centres in the world offering this technique and I was very fortunate to assist in one such case.

The third technique I learnt was the mesencephalic tractotomy. This involved lesioning the brainstem spinothalamic pathway. Its main indication was for pain involving the whole of one side of the body, including the face. I also watched midline myelotomies for the control of visceral pain.
I also had the opportunity to discuss cases and watch operations by the plastic surgery team. I was particularly interested in the use of peripheral nerve decompressions and transections to control pain.

Cosham

My next port of call was the Queen Alexandra Hospital in Cosham. I went to the pain unit several times to learn how to do image intensifier guided percutaneous cordotomies under Dr Nick Campkin. This unit was run by pain specialist hence it did not perform procedure involving the brainstem and the brain.

Outcome of scholarship

I shall summarise the outcomes :

  1. Development of a peripheral nerve decompression/ transection service at the neurosurgical unit in Romford

    - we have now performed 3 decompressions for meralgia paraesthetica and 2 operations for anterior abdominal cutaneous pain syndromes. The results have been very encouraging and we have published one such case (Triantafyllidis A, Mosharaf A, Low HL (2016) Chronic abdominal pain due to anterior cutaneous entrapment syndrome following an appendectomy: case report. Neurol Sci. 37(5): 823-824)

    - I have started an ultrasound guided peripheral nerve infiltration service together with the pain team and headache neurologists. Patients responding well to nerve blocks are considered for nerve decompressions. We have started a project comparing the outcomes of occipital nerve decompressions, occipital nerve blocks and occipital nerve stimulation for headaches

  2. In the process of developing a business case for a percutaneous cervical cordotomy service for terminally ill patients with poorly controlled pain. We have ascertained the level of interest and engaged interested palliative care and pain physicians, developed the referral pathway and obtained the quotes for the necessary equipment. Now all theatis left is the approval from the finance team. We hope to offer a cordotomy service by late 2017 for London and East of England. We estimate approximately 5 patients in the first year with the numbers rising in due course.

  3. We also hope to offer a trigeminal nucleotractotomy service for patients with poorly controlled head and neck pain and a mesencephalic tractotomy service for patients with hemibody pain


I thank the HCA International Committee for awarding me the Scholarship to acquire these new skills.