Vishwani Chauhan
Inaugural Talk: Imran Liaquat
and Neurosurgery
Early in his talk, Dr Imran told us that glioma is the biggest cause of death after unintentional injuries and suicide in people under 40. The cancer has no risk factors and surgery can have a variety of consequences depending on the anatomical localisation of where you cut. Dr Imran discussed not only the subject of gliomas, but also talked about the implications of treatment on the patient, evaluated EBM against anecdotal medicine, and put into perspective the ups and downs of a career in healthcare. This article hopes to touch on some of the highlights of his talk.
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Dr Imran began the talk by sharing that only 15% of practised medicine is EBM (RCTs). Most medicine that is practised is anecdotal and all studies in low grade gliomas are retrospective, so evidence and data to support the area are weak. Based on the studies that do exist, the practice of medicine evolves: earlier, surgery would only be carried out at the high grade stage, when the tumour started to transform. However now, surgery is only attempted if 90% or more of the tumour can be resected. This is because of two American studies(1,2) showing that patient outcomes are only significantly better when over 90% of the tumour is resected. The caveat to this change in practice, however, is that when carrying out the surgery, only about 70% of the time was more than 90% of the tumour actually resected in the operating theatre (when, according to plan, 90% or more of the tumour was supposed to be resected).
Tumours location has massive impact on this outcome. Dr Imran highlighted examples of areas of the brain where tumours can and cannot be successfully resected because of the consequences on quality of life. An example of an area where large parts of tumours can be resected is the eloquent cortex, which makes up about 40% of diffuse gliomas. Here, one can aim for a 70-80% resection due to CNS plasticity. However, in this scenario, iatrogenic damage still has a 20% risk of neurological deficit, which can be reduced by intraoperative monitoring to 10%. Insular tumours, on the other hand, have a high risk of morbidity from resection and have a 20-30% random risk of stroke, allowing resection to be attempted in select cases only.
Due to the possible consequences of surgery on attention, language, memory, and executive functions, and to justify the effects this would have on a person’s performance at work, a neuropsychology assessment is carried out before and after a surgery. It is also important to time the surgery around major life events if consequences on cognition and brain function will impact a patient’s ability to fully experience them.
Finally, in order to minimise neurological deficits post-surgery, the role of technology in the pre-operative workup cannot be understated. The classic MRI and PET scan can pick up hot spots that correlate with increased cellular activity, which is associated with cancer cells. This allows the healthcare team to identify the site of the pathology. Transcranial Magnetic Stimulation and Navigation adds to this by helping with surgical planning and decision making in eloquent lesions.
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Following this, an image guidance system is often used to reduce the size of the craniotomy and maximise tumour exposure. This system is known as neuronavigation and current technologies for this are Brainlab and Medtronic. Neuronavigation is integrated with microscope and ultrasound techniques. Ultrasound at the end of resecting a tumour helps identify any residual tumour. There is a learning curve to successfully identify residual tumour, but in experienced hands ultrasound is thought to be nearly as sensitive as an intraoperative MRI scan.
Dr Imran concluded his talk by reflecting on his career path and a surgeon’s behaviour. He discussed how the path to becoming an expert requires deliberate sustained practice, but he emphasised that there are always bumps along the way, reminding the audience that no one has gone through life without experiencing a major setback in their journey towards a goal. Quoting Prof K A Ericsson, a psychologist at Florida State University, Dr Imran concluded that “the differences between expert performers and normal adults are not immutable, that is, due to genetically prescribed talent. Instead, these differences reflect a life-long period of deliberate effort to improve performance.”
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References:
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(1)McGirt, Matthew J., et al. "Extent of surgical resection is independently associated with survival in patients with hemispheric infiltrating low-grade gliomas." Neurosurgery 63.4 (2008): 700-708.
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(2)Smith, Justin S., et al. "Role of extent of resection in the long-term outcome of low-grade hemispheric gliomas." Journal of Clinical Oncology 26.8 (2008): 1338-1345.
Dr Imran Liaquat is a consultant neurosurgeon based at the Western General Hospital. He has experience in all aspects of General Neurosurgery and Neuro-oncology including Awake Craniotomy, Fluorescence guided tumour resection, and management of Low Grade Gliomas. He is also a Senior Clinical Lecturer and Clinical Tutor at the University of Edinburgh.
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