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Writing books and learning neurosurgery by questions and answers

I recently published a book mainly aimed at doctors doing neurosurgery for their post-graduate end-of-training examinations, both the US residency boards and the UK FRCS(Neuro.Surg) exams among others.  It was quite an undertaking largely tackled by its hard working first author.

Neurosurgery Self-Assessment: Questions and Answers

It’s only my second foray into academic book publishing.  My first book published earlier in 2016 was more of an academic monograph related to my doctoral research with Mr. Alex Green and Mr. Jonathan Hyam in

Surgery of the Autonomic Nervous System

I have written over 20 book chapters, notably chapters on epilepsy surgery and imaging in the well known neurosurgical textbook Schmidek and Sweet, and recently the Basal Ganglia chapter with Prof. Tipu Aziz of the famous medical tome Gray’s Anatomy.  However, to write a whole academic book is a much more daunting commitment over a couple of years and it’s very gratifying to learn that the final product has been well received both in print and in its interactive online versions on ExpertConsult and Inkling.  The book is unique in containing the type of extended matching questions increasingly used in the British and other examinations.

I am delighted to learn from Elsevier that the question book is a best-seller among the neurosurgical community and that they are now doing a reprint within a few months of its release.  This gives us a great opportunity to incorporate feedback from the trainees and established neurosurgeons who have read it and spotted any first edition typos or other minor points for correction!

Amount of spinal tumour removed determines how much leg function improves (and experience, not tick boxes, turns novice neurosurgeons into experts)

Much of surgery consists of intuitive decision making.  This, in part, explains why patients seek out experienced surgeons.  It is hoped that neurosurgical experience, be it personal, from reading or researching, or from observing others, creates a rich frame of reference to draw upon when making both clinical decisions and fine hand movements  when manipulating someone’s brain or spine during an operation – or reacting to the unexpected.

I have an interest in surgical education and there is a particular scientific literature on the amount of experience and cognitive processing of it required to transition from novice to expert which is quite intriguing.  It’s often oversimplified to 10,000 hours  – which is probably the clinical experience gained in a good British neurosurgical training programme, although no high quality studies have been done either to confirm this or the validity of the many tick box exercises that UK neurosurgical trainees now have to go through.

I recently published a paper looking at clinical outcomes of surgery for spinal ependymoma, a particular type of common spinal tumour occurring intradurally (inside the dura mater lining the spinal cord and spinal nerves) and arising from ependymal cells that line the internal fluid spaces of the spinal cord.

Optimising treatment strategies in spinal ependymoma based on 20 years of experience at a single centre.

As a study of 61 patients with spinal ependymoma, it is one of the largest single centre studies published.  We confirmed what many surgeons suspect intuitively – the more tumour that is removed, the better the patient’s outcome, both in terms of survival and improvement in leg power and function.

On deeper analysis, the finding is not quite as intuitive as it sounds because the tumour surgeon’s dilemma is whether removing the last remnants of a tumour might damage normal functional neural tissue and cause a new deficit.  This is a particular challenge in eloquent brain tumour surgery and numerous tools from special dyes and awake surgery to intra-operative stimulation, electrical monitoring and transcranial magnetic stimulation have been introduced to assist resections.

The message is that careful and diligent gross, total resection of intradural spinal tumours remains desirable for best outcomes.  This is something that I endeavour to do in my practice as a neurosurgeon and complex spinal surgeon.  Transient, and unfortunately permanent, weakness remain risks of surgery on spinal tumours, but in my experience aggressive surgical resection confers best outcome.

Can deep brain stimulation or spinal cord stimulation improve spinal cord injury?

This is an exciting field of research.  I am lucky to be working as an academic consultant neurosurgeon in a University Hospital with an academic neurosurgeon colleague, Professor Marios Papadopoulos, an experienced general, complex spinal and vascular neurosurgeon whose current research is yielding fascinating insights into acute spinal cord injury (SCI) that may change its initial treatment and improve outcomes.

One of my research interests lies at the interface of spinal cord injury and neuromodulation with the question of whether brain computer interfaces can improve the disabling signs and symptoms of SCI.  We just published a review of the field:

Surgical Neurostimulation for Spinal Cord Injury.

SCI is a devastating neurological condition characterized by a constellation of symptoms including paralysis, paraesthesia, pain, cardiovascular, bladder, bowel and sexual dysfunction. Current treatment for SCI involves acute resuscitation, aggressive rehabilitation and symptomatic treatment for complications. Despite the progress in scientific understanding, regenerative therapies are lacking. In this review, we outline the current state and future potential of invasive and non-invasive neuromodulation strategies including deep brain stimulation, spinal cord stimulation, motor cortex stimulation, transcutaneous direct current stimulation and repetitive transcranial magnetic stimulation in the context of SCI. We consider the ability of these therapies to address pain, altered sensation, weakness, blood pressure and bladder problems (autonomic dysregulation) associated with SCI. In addition to the potential to make important contributions to SCI treatment, neuromodulation has the added ability to contribute to our understanding of spinal cord neurobiology and the pathophysiology of SCI.

The prospect of using spinal cord stimulation to improve spinal cord injury is appealing as it is a procedure I already perform regularly to treat chronic pain when medicines don’t work.  Similarly, I do deep brain stimulation surgery frequently to treat Parkinson’s disease.  I also perform deep brain stimulation and motor cortex stimulation for chronic pain, but unfortunately these treatments are generally not NHS funded so I can only do the surgeries privately or internationally.

My own doctoral research during my neurosurgical training investigated the role of deep brain stimulation of a structure called the midbrain periaqueductal grey to relieve chronic pain, and its effect upon autonomic function, supervised by two established academic functional neurosurgeons at Oxford University, Mr. Alex Green and Prof. Tipu Aziz.  Modern biomedical science progresses through incremental discoveries building on a body of knowledge and expertise, rather than Eureka moments, so to investigate deep brain stimulation for SCI would be a natural continuation of that award winning research.

Saving patients radiation (and the NHS money) by avoiding unnecessary X-rays after spinal surgery

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The British Journal of Neurosurgery, which has published a few of my papers in the last decade and which I believe in supporting as it is the journal of my society – The Society of British Neurological Surgeons, just published my recent paper on cervical spine surgery:

Routine radiographs one day after anterior cervical discectomy and fusion are neither necessary nor cost-effective.

This refers to a particular type of surgery commonly done by myself and other neurosurgeons for slipped discs in the neck causing neck or arm pain or limb weakness called anterior cervical discectomy and fusion (ACDF).  The surgery involves clearing out the disc space (ideally with a microscope!  do please ask your spinal surgeon if they use one) and replacing it with a small cage made from a special plastic, PEEK, or titanium and bone graft or substitute.  We showed that not doing X-rays one day after surgery not only reduced the patient’s stay in hospital by up to a day or two, but also reduced radiation to the patient and did not change their management.  The tiny proportion of patients who had problems after surgery would have MRI scans ultimately.  We estimated saving that department (neurosurgery at Oxford University Hospitals) close to half a million pounds a year with this service improvement audit.

There are minor caveats to this practice.  One needs to use X-rays during surgery to check that the correct level has been operated on and it’s good to do another X-ray 2-3 months later to confirm that the cage has fused the spinal bodies together.  Not X-raying one day after surgery is best restricted to single and two level ACDFs as for multi-level constructs, knowing the shape of the neck and cage positions after surgery is desirable.  I performed and published one of the few robust case series of three and four level ACDF surgeries without need for additional plating, together with one of my complex spinal surgery mentors, Mr Tom Cadoux-Hudson, a truly inspiring role model and great neurosurgeon who taught me many dexterous tricks during my Oxford neurosurgical training.

XLIF lumbar spinal fusion improves pain and quality of life in challenging situations

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I recently published a case series of patients with either complex medical problems or complex past spinal surgery (or both!) who had received XLIF surgery.  This was from work and surgeries done during my complex spinal surgery fellowship at Guy’s and St Thomas’ Hospital with Mr. Khai Lam, a technically excellent orthopaedic spinal surgeon now working at London Bridge Hospital.

XLIF (eXtreme Lateral Interbody Fusion) is a minimally invasive spinal fusion surgery where a small cut is made in the patient’s flank and an artificial cage filled with bone substitute inserted into the disc space.  Our experience was that it was best complemented by minimally invasive percutaneous pedicle screws placed on both sides of the spine to keep the construct straight and strong.  My take home message from my research is that, with XLIF being a brief surgery with a small cut and minimal tissue disruption and muscle cutting compared to some other fusion surgeries like conventional TLIF or PLIF, it is well suited to patients who might have medical problems like obesity, diabetes, atrial fibrillation or otherwise not be the best candidates for a bigger operation.  Patients went home soon after surgery with pain and quality of life much improved.  My research showed it can effectively ‘indirectly decompress’ moderately squashed spinal nerves.

Other advantages of XLIF are that the wider surface area of the cage means fusion should be at least as good as for TLIF and for patients with a curved or a flat back, the scoliosis can be corrected somewhat and the lordosis improved.

Two important drawbacks to XLIF are that it is limited to certain levels of the lumbar spine (best from T12 to L5) and that there is a fair risk of altered or reduced sensation in the legs, in particular the feet.  This commonly resolves after a few weeks and is usually due to traction on the lumbosacral plexus.  I’ve found the best way to minimise this risk is to be in and out of the XLIF part of the surgery as quickly as possible.  I use lumbosacral plexus monitoring for the surgery to keep this risk down.

XLIF is a recent and useful addition to the complex spine surgeon’s thoracolumbar spinal surgical toolbox and I’m pleased to be able to make a contribution to the literature on it and add it to the list of surgeries I can offer patients for whom it is best suited.