Advanced Electrophysiology

Details

Title

Advanced Electrophysiology

Type

Stage Two

Module code

HPS251

Requirement

Compulsory

Module objective

By the end of this module the Clinical Scientist in HSST, in respect to advanced electrophysiology, will be able to apply their expert knowledge, skills and experience in the clinical setting to review emerging evidence of new developments in scientific, technological and clinical practice with respect to advanced electrophysiological techniques in the clinical setting and also those undertaken during intraoperative monitoring. These techniques will include:

• somatosensory evoked potentials following sensory nerve stimulation;
• magnetic stimulation of the central and peripheral the nervous system;
• somatosensory evoked potentials during surgery of the spinal cord;
• motor evoked potentials during surgery of the spinal cord.The Clinical Scientist in HSST will also be able to formulate an appropriate investigation/monitoring strategy for each patient, analyse, interpret and where appropriate provide comprehensive supervised clinical reports. Within their scope of practice they will be able to form differential diagnoses and will formulate an appropriate plan for investigation and management, in conjunction with medical colleagues, being aware of the need to expedite investigation in suspected serious disease. They will be aware of the need to refer appropriately for medical intervention or further investigation by other healthcare practitioners.

This spans the design and application of appropriate neurophysiological measurement techniques to measure, assess and monitor the functional integrity of the peripheral and central sensory and motor pathways in a range of disease conditions and the function of the spinal cord during orthopaedic surgery in and around the spinal canal, and the design and application of appropriate neurophysiological measurement techniques to evaluate the function of the sensory and corticomotor pathways of the central and peripheral nervous system.

The Clinical Scientist in HSST will also be able to formulate an appropriate investigation/monitoring strategy for each patient, analyse, interpret and where appropriate provide comprehensive supervised clinical reports. Within their scope of practice they will be able to form differential diagnoses and will formulate an appropriate plan for investigation and management, in conjunction with medical colleagues, being aware of the need to expedite investigation in suspected serious disease. They will be aware of the need to refer appropriately for medical intervention or further investigation by other healthcare practitioners.

The Clinical Scientist in HSST will also be expected to identify opportunities for innovative approaches to the development, delivery and evaluation of new clinical electrophysiology services and lead these developments.

Knowledge and understanding

By the end of this module the Clinical Scientist in HSST will be able to analyse, synthesise, evaluate and critically apply their expert knowledge, including:

Underpinning science:

• clinical and functional anatomy and physiology of the central and peripheral sensory and motor pathways;
• the pathophysiology of diseases that affect the sensory and motor pathways;
• clinical and functional anatomy, physiology and pathophysiology relevant to spinal cord surgery, and function and the monitoring of these pathways during surgery, including embryology and development;
• pharmacology and therapeutics relevant to spinal cord monitoring and assessment in a clinical setting and during surgery.

Clinical considerations:

• protecting patients of paediatric age and vulnerable adults from maltreatment, abuse, neglect, or exploitation (safeguarding);
• informed consent in adults and children;
• clinical investigations relevant to disorders of the sensory and motor peripheral and central nervous system pathways;
• current guidelines and standards used for magnetic stimulation;
• safety and contraindications of transcranial electrical and magnetic stimulation;
• current guidelines and standards used for somatosensory evoked potentials following cutaneous nerve or dermatomal stimulation;
• clinical investigations relevant to spinal cord surgery and monitoring;
• surgical procedures undertaken in spinal deformity correction and other spinal surgery requiring neurophysiological monitoring;
• risks and mechanisms of neurological injury associated with surgical procedures;
• current guidelines for performance of intraoperative neurophysiological monitoring techniques;
• current guidelines on individual responsibilities of members of the monitoring team and advised action relating to adverse events;
• the importance of performing all neurophysiological procedures in accordance with recognised guidelines.

Technical and clinical monitoring:

• important technical considerations, such as:
  • electrode characteristics
  • filter settings
  • amplifier characteristics
  • the principles of computerised signal averaging and artefact rejection
  • how to recognise and correct common artefacts during recordings
  • regular system calibration for stimulators and recorders
  • the effects of medication and anaesthesia and other systemic factors on the nervous system and the recorded neurophysiological potentials
• formulating a plan with surgical and anaesthetic staff to monitor and map the neurological structures at risk during spinal and orthopaedic surgery and devise a strategy for timely and effective feedback;
• formulating an investigative plan with the referring clinicians to select the most relevant test for the recording of the pathway under investigation;
• stimulus modalities;
• pathophysiology of conditions where neurophysiology recordings are indicated during spinal deformity surgery, including:
  • scoliosis
  • kyphosis
  • spondylolisthesis
  • thoracic/lumbar fusion/decompression/correctiondisease
• pathophysiology of conditions where neurophysiological recordings of the central sensory and motor pathways using somatosensory and motor evoked potentials are indicated, including:
  • peripheral neuropathy
  • radiculopathy
  • myoclonus
  • multiple sclerosis
  • cerebrovascular
  • coma

Indications for and limitations of:

Somatosensory evoked potentials:

• selection of cutaneous and dermatomal stimulation sites of the upper and lower limb;
• significance of using appropriate stimulus levels to elicit the responses;
• selection of peripheral and central and cortical recording sites to record the potentials;
• the effects of disease on the nervous system.

Intraoperative somatosensory evoked potentials (SEPs):

• upper limb SEPs, including:
  • the use of upper limb SEPs as a means to monitor the cervical nerve roots and cord during surgery in and around the cervical region
  • the significance of using appropriate stimulus and recording sites
  • the use of upper limb SEPs as a means of a control for surgery below the level of the cervical region
  • the significance of a significant change in neurophysiological potentials amplitude and latency during surgery
  • the effects of neurological disease on upper limb SEP potentials
• lower limb SEPs, including:
  • the use of lower limb SEPs as a means to monitor the lumbar roots during surgery in and around the lumbar region
  • the significance of using appropriate stimulus and recording sites
  • the use of lower limb SEPs as a means of to monitor the lumbar and thoracic cord during surgical procedures that put these structures at risk
  • the significance of a significant change in neurophysiological potentials amplitude and latency during spinal surgery
  • the effects of neurological disease on lower limb SEP potentials.

Transcranial motor evoked potentials:

• stimulus parameters, including:
  • the selection of cortical derivations to optimise the motor evoked potential of interest
  • the selection of stimulus parameters to optimise the motor evoked potential of interest
• peripheral recordings, including:
  • significance of muscle recording site selection
  • use of motor evoked potentials after transcranial electrical stimulation to monitor the integrity of the cervical, thoracic and lumbar spinal cord
  • significance of a significant change in recorded motor potential during surgery
  • the effects of neurological disease on motor evoked potentials.

Technical and clinical skills

By the end of this module the Clinical Scientist in HSST will have a critical understanding of current evidence and its application to the performance and mastery of a range of technical skills and will:

Intraoperative monitoring:

• perform ‘control’ upper limb somatosensory evoked potentials in theatre during surgery in and around the thoracic and/or lumbar region;
• design, develop, implement and evaluate appropriate recording techniques for the sensory spinal cord pathways;
• perform ‘control’ upper limb motor evoked potentials in theatre during surgery in and around the thoracic and/or lumbar region.

Somatosensory evoked potentials:

• perform ‘control’ dermatomal/cutaneous somatosensory evoked potentials in a range of patients;
• interpret the results in comparison to normative data.

Magnetic stimulation:

• perform ‘control’ transcranial magnetic evoked motor potentials to assess the functional integrity of the central nervous system;
• record the absolute latency and amplitude of the muscle potentials;
• calculate the central motor conduction time using peripheral measurement techniques (i.e. F-waves or foraminal stimulation);
• interpret the results in comparison to normative data.

By the end of this module Clinical Scientist in HSST will be expected to critically reflect and apply in practice a range of clinical and communication skills with respect to the recording and interpretation of a range of evoked potentials in a range of settings, including non-dedicated areas such as theatres. They will communicate effectively with patients, relevant clinicians and other healthcare professionals and will:

• take a relevant, focused history, when appropriate in collaboration with the supervising clinician;
• select and perform the appropriate investigations, taking into account pathologic and non-pathologic contraindications and risks that affect the neurophysiological recordings;
• analyse all the recorded neurophysiological data;
• discuss the effects of anaesthesia on the neurophysiological recordings with the anaesthetic team to determine the optimal regimen;
• communicate effectively with the anaesthetic and surgical teams any significant changes in the neurophysiological recordings and their underlying pathophysiology;
• provide a clinical interpretation of the neurophysiological data, placing the results in the context of patient history and clinical examination and surgical procedure;
• produce a clear and informative clinical report;
• advise and communicate effectively with relevant clinicians, patients and the public, and other healthcare professionals working within the multidisciplinary team;
• adapt current tests and develop novel evoked potential recording techniques to better facilitate the investigation the range of neurological conditions presented;
• consistently work to high standards of clinical practice applying knowledge and evidence, making decisions and evaluating the impact of those decisions;
• monitor, evaluate and maintain clinical practice standards;
• balance data confidentiality, security and protection, and the sharing of data with relevant stakeholders, including patients, to ensure high-quality patient- centred care;
• critically review the literature, disseminate findings and scientific data, and make recommendations for future activity;
• ensure clinical and scientist colleagues are kept up to date with new and novel techniques used within the service;
• work with patients, carers, parents and family members as appropriate to develop and update patient information materials appropriate to service requirements;discuss the effects of anaesthesia on the neurophysiological recordings with the anaesthetic team to determine the optimal regimen;
• share data on clinical practice standards with service users and managers to encourage dialogue and debate;critically reflect on the challenges of applying research to practice in relation to these areas of practice and suggest improvements, building on a critique of available evidence.
• support and contribute to the development of multidisciplinary clinical team working and work with the team to determine scientific service priorities;
• be committed to and support continuous improvement of neurophysiological services, with particular reference to auditing practice, evidence-based practice, innovation, new and improved technologies;
• critically reflect on the challenges of applying research to practice in relation to these areas of practice and suggest improvements, building on a critique of available evidence.