Background
Intraoperative neurophysiological monitoring (IONM) provides the surgeon operating on the spine with a highly sensitive and specific early warning of potentially reversible neurological change1. It has become a standard of care during spinal deformity surgery in the US and demand is growing exponentially in Europe. The traditional “wake-up test” has a number of well-documented limitations2,3. that make it inadequate for monitoring during spinal deformity surgery and it has become obsolete in many centres4. Multimodal IONM techniques enable safe and continuous assessment of motor and sensory pathways, as well as individual nerve roots, where necessary. Neurophysiological monitoring technology is evolving at a startling rate and it is increasingly important that the IONM provider is well trained, qualified and highly experienced. Their role is to work alongside surgical and anaesthetic staff to accurately identify true positive neurological changes in spinal cord function and avoid common pitfalls that can lead to false positive and false negative errors.
In the last few years, the Clinical Society of Neurophysiology has acknowledged a UK-wide shortage of Consultant Clinical Neurophysiologists (CCNs). This, combined with shortening Department of Health waiting time targets and increasing numbers of patients requiring neurophysiological monitoring, has led to an unworkable situation which could lead to greater morbidity in terms of irreversible pathophysiology and patient outcomes5. In an effort to improve the quality and throughput of neurophysiological investigations, there has been a marked extension in the working practice of Clinical Physiologists (CPs), formerly known as Medical Technical Officers or Neurophysiology Technicians. Senior, “Highly Specialised” Clinical Physiologists (HSCPs) are now found working in theatres autonomously without any attendance by a CCN or with remote supervision by a CCN.
Suitably qualified and experienced HSCPs must aim to provide comprehensive IONM services that are robust, reliable and readily adaptable to the needs of the individual patient and particular surgical conditions.
High quality IONM not only offers the surgeon protection medically but also medico-legally. If a patient were to sustain a severe iatrogenic neurological complication during spinal surgery, it is possible that damages awarded may run into the millions. The IONM provider may be asked to be a witness in court or produce a statement. For this reason, it is essential that the IONM event log, compiled throughout the surgery by the HSCP and time-locked to the recorded waveforms, is of impeccable quality: continuous, complete and tamperproof.
It is likely that the emergence of HSCP-led services will continue throughout Europe over the next decade and so associated systems must be implemented to monitor quality of practice and ensure that high standards are maintained.
Safety audit
The Scottish National Spine Deformity Service is a well-established centre, based at the Royal Hospital for Sick Children and the Royal Infirmary in Edinburgh, providing care for children and young adults with a range of spinal deformities. Patient conditions may include: idiopathic scoliosis, congenital spine deformities, Scheuermann’s kyphosis, severe spondylolisthesis and neurological conditions such as cerebral palsy and Duchenne muscular dystrophy. The service depends largely upon a highly skilled, experienced and dedicated team of surgeons, clinical physiologists, nurses, anaesthetists, operating department practitioners and many other contributing health professionals.
In 2000, Dr Michael Glasby, a Consultant Clinical Neurophysiologist (CCN), designed and set-up a service with the aim of providing routine intraoperative neurophysiological monitoring of spinal cord function during surgery for treatment of scoliosis or other spinal pathology. Dr Glasby routinely provided this successful service, until his retirement in 2009.
In 2007, prior to his retirement, and in the absence of a CCN successor, the decision was made to “hand-over” the service to a small team of Highly Specialised Clinical Physiologists (HSCPs) working within the Department of Clinical Neurophysiology. Over a period of two years, the HSCPs were intensively trained and in 2009, they began performing IONM in pairs, with no attendance by a CCN.
The HSCP team were mindful of the significant transition from a CCN to a clinical physiologist-led neurophysiology service and the crucial need for quality control. Therefore in 2010, with the full involvement of Mr Christopher Adams (Consultant Spinal Surgeon) and Dr Glasby, the HSCP team embarked on an audit entitled “Can clinical physiologists provide a safe, independent intra-operative monitoring (IOM) service in paediatric spine deformity surgery?”, the full results of which are soon to be published6. This audit was performed in accordance with the current National Institute for Clinical Excellence guidelines (2002) -“Principles of Best Practice in Clinical Audit”7.
The audit involved the analysis and comparison of IONM records over two time periods, each lasting two months: April – June 2009 (Group 1) and April – June 2010 (Group 2). All HSCPs were blinded to the study.
The incidence and nature of neurophysiological “events” during these two periods were reviewed retrospectively by the CCN and the data compared with those identified intra-operatively by the HSCP team.
Group 1 (pre-intervention)
The first time period was shortly after the “hand-over” of the IONM service from the experienced CCN to the HSCP team. The waveforms, event logs and reports fr