Fixing the head to the spine (and the broken bones in between)

The head sits on seven bones of the neck, perfectly balanced like a ball on a stick.  Three of these cervical vertebrae are quite different from the others in shape and in function – the seventh on which the others perch and the first and second upon which the head sits.

Whole books have been written about the ‘craniocervical junction’ and some neurosurgical authorities make their names and reputations in it.  I enjoy craniocervical surgery and often think it and intradural surgeries are two of the operations that fall more into the repertoires of complex spinal neurosurgeons (versus complex spinal orthopaedic surgeons).

The atlas (C1) rotates on the peg of the axis (C2) and the head flexes and extends on the atlas, all of these structures being attached by several short, strong ligaments and muscles.  In a variety of conditions from trauma, infection, cancer, abnormal development to rheumatoid arthritis (much more rare in the last decade with modern advances in disease modifying drugs), these bones or their attachments can become broken or deranged, necessitating fixation.

The neck can be ‘fixed’ simply by wearing a hard collar for a couple of months, but it does not always fix in the right position and the bones may not always unite in the correct orientation.  An alternative is fitting of a halo jacket which uses four pins in the skull and a tight fitting mould over the shoulders and chest to keep the neck rigid.  It can be uncomfortable, difficult to bathe in and, for some, difficult to breathe easily in.  I have seen the best results from halos in children, rather than the elderly who more commonly fracture cervical vertebrae.

There are several operations that can fix C1 to C2, should their connections be disrupted by breaking part of the odontoid peg of C2 or the ring of C1 for example.  In some circumstances a  ‘peg screw’ placed through the front of the neck can pull it down and into alignment and fix it in place.  More commonly, the fracture is such that surgery from the back of the neck is indicated.

We recently published a significant case series of a very strong construct for fixing C1 to C2:

Combined C1-C2 Transarticular with C1 Lateral Mass Screw Fixation for the Treatment of Atlantoaxial Instability: A Single Center Experience

I contributed most of the patient data to this case series, operated on by one of my complex spinal surgery mentors, Mr. Tom Cadoux-Hudson.  I was proud to publish the results in an Indian journal, firstly because the operation was first described by an Indian neurosurgeon who has made his name in the craniocervical junction, Prof. Atul Goel of Mumbai whom I once met in Kuala Lumpur in 2010 and who was most cordial in encouraging me to visit and see how he operated.  Secondly because around that time, I published a case report on the same operation to treat a particular type of infection by the spine grandly called La Maladie de Grisel, and had a slightly heated correspondence with him about the origins and nuances of his ‘double insurance’ operation.  Finally, the paper was a career defining one for my contemporary at Oxford University Hospitals, Mr. Murtuza Sikander, who also trained in India and was recently able to establish himself at Oxford after its publication.

There are a few methods of fixing C1 and C2 posteriorly:

The early Goel method which we describe in the paper.

Magerl’s method of just passing a long screw through the joint between C1 and C2.

Harms’ method of passing C1 lateral mass and C2 pars screws and joining them with rods on each side.  This is most surgeons’ (including my) preferred method as it is very strong with less risk of vertebral artery injury than the above two methods.

Slightly more historically,

Brooks’ fusion

Gallie fusion

All of this illustrates that there are many ways to skin a cat, even (especially?) in neurosurgery and complex spinal surgery and that one should choose an experienced surgeon exposed to most if not all of these methods and comfortable with at least one which they choose for good clinical and scientific reasons, not just because that’s the one they were taught.  With more experience, I now perform a different operation (Harms) to the one I was first taught (early Goel) as I think to all practical purposes it is just as strong, but less risky and less difficult to do well.  Neurosurgeons shouldn’t do the most difficult operation they can just because they think they can.  It comes back to the Hippocratic aphorism that entitles the recent bestseller of my St George’s consultant neurosurgeon colleague whose many stories from the neurosurgical frontline I thoroughly enjoy listening to, Mr. Henry Marsh.  Do no harm.

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


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.