Neurosurgical Monitoring

Details

Title

Neurosurgical Monitoring

Type

Stage Two

Module code

HPS256

Requirement

Optional

Module objective

By the end of this module the Clinical Scientist in HSST will be able to apply their expert knowledge of the principles, instrumentation, methodology, clinical application and risks of neurological monitoring in adults and children, including supratentorial monitoring, cranial nerve monitoring, peripheral nerve monitoring and sacral nerve monitoring. Their knowledge will include the clinical indications for each type of monitoring, selection of equipment and techniques, interpretation of monitoring information and communication with the multidisciplinary team.

The Clinical Scientist in HSST will be expected to perform a range of technical, clinical and communication skills, and consider the needs and views of the patients and their families undergoing procedures requiring neurological monitoring, treating patients and their families with kindness and compassion. They will be able to identify opportunities for innovative approaches to the development, delivery and evaluation of new clinical services and lead these developments. In addition they will have expert knowledge of management systems for the integration, dispersal, storage and access of results. They will keep up to date with the evidence base underpinning developments in technology that may be translated to and enhance neurological monitoring, including patient safety and the development of clinical services. The Clinical Scientist in HSST will also consistently demonstrate the attitudes and behaviours necessary for the role of a Consultant Clinical Scientist.

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 to monitor and map the neural structures for neurosurgical procedures, including:

• supratentorial surgery, including:
  • glioma resection
  • resection of epileptic foci
  • arteriovenous malformations
  • deep brain stimulation
• posterior fossa surgery, including:
  • vestibular schwannomas
  • cerebellar pontine angle tumours
  • microvascular decompression
• spinal cord surgery, including:
  • cervical cord tumours
  • intramedullary spinal cord tumours
  • extradural lesions
  • nerve root tumours
• sacral surgery, including:
  • spinal dysraphism
  • lipomeningomyelocele
  • diastematomyelia
  • selective dorsal rhizotomy.

The Clinical Scientist in HSST will also be able to analyse, synthesise, evaluate and critically apply their expert knowledge to:

Underpinning science:

• the clinical and functional anatomy, physiology and pathophysiology relevant to neurological monitoring, including development and embryology;
• the pharmacology relevant to spinal cord surgery and monitoring.

Clinical considerations:

• clinical investigations relevant to neurological monitoring;
• protecting patients of paediatric age and vulnerable adults from maltreatment, abuse, neglect, or exploitation (safeguarding);
• informed consent in adults and children;
• surgical procedures for which neurological monitoring is undertaken;
• risks and mechanisms of neurological injury associated with surgical procedures;
• current guidelines for performance of intraoperative neurological 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:

• the importance of technical considerations, including:
  • electrode characteristics
  • filter settings
  • amplifier characteristics
• the principles of computerised signal averaging and artefact rejection;
• how to recognise and correct common artefacts during recordings;
• the importance of regular system calibration for stimulators and recorders;
• the effects of anaesthesia and systemic factors on the nervous system and the recorded neurophysiological potentials recorded during surgery;
• how to formulate a plan with surgical and anaesthetic staff to monitor and map the neurological structures at risk during neurosurgery and other surgeries and devise a strategy for timely and effective feedback.

Supratentorial monitoring:

• pathophysiology of conditions where neurophysiology recordings are indicated during surgery involving the cerebrum, including
  • epilepsy surgery
  • supretentorial tumour resection
  • cerebrovascular surgery:
    • aneurysm surgery
    • arteriovenous malformations

• functional neurosurgery (deep brain stimulation):
  • Parkinson’s diseasetranscranial MEPs to monitor the corticobulbar pathways;
• the role of somatosensory localisation techniques for neurosurgical procedures around the sensorimotor cortex;
• the role of direct cortical stimulation to monitor the corticospinal tracts during surgical procedures involving the motor cortex;
• the role of subcortical stimulation to map the white matter tracts during surgical procedures involving the motor cortex;
• the role of direct cortical and subcortical stimulation to map the eloquent speech and language areas during awake craniotomies;
• the use of SEPs and MEPs.

Cranial nerve monitoring:

• pathophysiology of conditions where neurophysiology recordings are indicated during surgery involving the brainstem, including:
  • cerebellar pontine angle/posterior fossa tumours:
    • vestibular schwannoma resection
    • extra axial tumours
    • intra axial tumours
• microvascular decompressive surgery:
  • trigeminal neuralgia
  • hemifacial spasm
  • glossopharyngeal neuralgia
• the application of cranial nerve monitoring techniques for surgery in and around the brainstem;
• the use of cranial nerve recordings to monitor and map the neurological function of the during neurosurgical procedures;
• recording and stimulating techniques for the motor cranial nerves (III, IV, V, VI, VII, IX, X, XI, XII);
• transcranial MEPs to monitor the corticobulbar pathways;the utility of free-running and evoked EMG recordings to map and monitor the integrity of the sacral nerve roots;
• stimulating and recording techniques for the auditory nerve (brainstem auditory evoked potentials);
• stimulating and recording techniques for the lateral spread response to determine the extent of microvascular decompression of the facial nerve for hemifacial spasm.

Spinal cord monitoring:

• pathophysiology of conditions where neurophysiology recordings are indicated during surgery involving the spinal cord, including:
  • intramedullary spinal cord tumours
  • spinal tumours
  • spinal root schwannomas
  • aortic aneurysm dissection/grafting
• the role of somatosensory and MEP recordings to monitor the functional integrity of the spinal cord during neurosurgical and vascular procedures that place the nervous system at risk;
• the utility of epidural motor recordings (D waves) to maintain motor monitoring during intramedullary spinal cord tumour resection.

Sacral nerve monitoring:

• pathophysiology of conditions where neurophysiology recordings are indicated during surgery of the sacral and cauda equina region, including:
  • sacral tumours
  • tethered cord release
  • selective dorsal rhizotomy for spastic diplegia
• the role of somatosensory and transcranial MEP recordings to monitor the integrity of the sacral nerve roots;
• the utility of free-running and evoked EMG recordings to map and monitor the integrity of the sacral nerve roots;
• the role of the bulbocavernosus reflex to assess the ascending, intraspinal and descending pathways involved in this response;
• the role of neurophysiological mapping techniques for the identification and subsequent grading of dorsal rootlets during neurosurgical procedures to relieve spasticity (selective dorsal rhizotomy);
• the intraoperative neurophysiological correlates of certain clinical conditions such as neurological, neurosurgical and orthopaedic disorders;
• optimising the diagnostic value of intraoperative neurological monitoring;
• the sensitivity and specificity of a range of methods of neurological monitoring of the spinal cord to predict impending neural injury;
• monitoring the outcome of surgery, including the patient perspective.

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:

• design and develop suitable multimodal recording techniques that are tailored for the patient’s clinical disorder and which meet the needs of the supervising surgeon;
• perform SEPs and MEPs during neurosurgical and other procedures involving the spinal cord and nerve roots;
• perform cranial nerve monitoring and mapping techniques during neurosurgical procedures in and around the brainstem;
• record and interpret SEPs to localise the sensory cortex/central sulcus (phase reversal);
• record MEPs after cortical and subcortical stimulation to monitor and to map the corticospinal tracts;
• interpret and collate the results of SEPs and MEP recordings to the vascular supply during cerebrovascular surgery;
• identify neural tissue during detethering procedures;
• record and interpret the bulbocavernosus reflex (BCR);
• determine the stimulus threshold of the individual nerve roots during selective dorsal rhizotomy;
• grade the response to titanic stimulation of individual nerve rootlets during selective dorsal rhizotomy;
• interpret the neurophysiological recordings obtained during neurosurgical procedures in light of pathologic changes;
• reflect on the challenges of applying research to practice in relation to the use of spinal cord monitoring in clinical practice and suggest improvements, building on a critique of available evidence;
• promote the importance of innovation in neurological cord monitoring.

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 neurosurgical procedures that put the nervous system at risk of damage and compromise. 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;
• perform the appropriate investigations, taking into account pathologic and non-pathologic contraindications and risks that affect the intraoperative neurophysiological recordings;
• take a holistic approach to neurological monitoring and provide an accurate and comprehensive assessment of the patient’s clinical problem;
• analyse all the recorded neurophysiological data during the surgical procedure;
• 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, clinical examination and surgical procedure;
• produce a clear and informative clinical report;
• advise and communicate effectively with patients, relevant clinicians and the public, and other healthcare professionals working within the multidisciplinary team;
• strive to adapt current tests and develop novel intraoperative recording techniques to better facilitate monitoring and mapping of the cerebrum, spinal cord, brainstem and sacral nerves during surgery, ensuring the safety of the patient at all times;
• 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 and 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 and parents to develop and update patient information materials appropriate to service requirements;
• share data on clinical practice standards with service users and managers to encourage dialogue and debate;
• 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 neurological monitoring services, with particular reference to auditing practice, evidence- based practice, innovation, new and improved technologies;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.