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Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP)
Includes bibliographical references
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Surgery
2016
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| _version_ | 1867613205253062656 |
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| access_status_str | Open Access |
| author | Padayachy, Llewellyn |
| author2 | Fieggen, Anthony Graham |
| author_browse | Fieggen, Anthony Graham Padayachy, Llewellyn |
| author_facet | Fieggen, Anthony Graham Padayachy, Llewellyn |
| author_sort | Padayachy, Llewellyn |
| collection | Thesis |
| description | Includes bibliographical references |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/16787 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:26.116Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Surgery |
| publisherStr | Department of Surgery |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/16787 Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) Padayachy, Llewellyn Fieggen, Anthony Graham Selbekk, Tormod Neurosurgery Includes bibliographical references Background: Assessment of intracranial pressure (ICP) is an essential aspect in the management of most neurosurgical conditions in children. While invasive ICP monitoring is considered the criterion standard, the need for a reliable, non-invasive, easy-to-use and accurate method to detect and monitor raised ICP has inspired the development of many useful techniques. The present study examined the relationship between transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) and invasively measured ICP in children, as well as the influence of relevant physiological and demographic variables on this relationship. Methodology: ONSD measurement was performed using a high frequency, small footprint linear array probe, and prior to invasive ICP measurement. All patients were under general anaesthesia and being mechanically ventilated. Physiological variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate, temperature, respiratory rate and end tidal carbon dioxide (ETCO2) level were recorded at the time of ONSD measurement. The ONSD measurements were analysed for repeatability, intra- and inter-observer variability as well for correlation between images acquired in different planes and those obtained from either eye. The diagnostic accuracy of ONSD measurement for detecting ICP at different thresholds of 20, 15, 10 and 5 mmHg was analysed. This analysis included evaluation of age-related thresholds for defining different ONSD cut-off values in children. Dynamic image acquisition was performed and analysed to evaluate the relevant pulsatile motion of the ONS as a marker of the sheath stiffness. Results: One hundred and seventy four children undergoing diagnostic or therapeutic surgical procedures were included in this study. ONSD measurement demonstrated good correlation with ICP across the entire patient cohort (r = 0.66, p < 0.001), but was better in children > 1 year or with a closed anterior fontanelle (AF) (r = 0.7, p < 0.001). Age above and below 1 year was found to be an appropriate age threshold for defining two different sets of ONSD cut-off values. The study however, supported using patency of the AF as a stronger clinical marker for describing different ONSD cut-off values in children. The second part of this work described a dynamic technique for analysing the pulsatile motion of the ONS. Analysis of the deformability index (DI) as an indirect marker of ONS stiffness, revealed a statistically significant relationship with ICP (sensitivity of 90%, specificity of 87% for detecting ICP ≥ 20 mmHg). Conclusion: Measurement of the ONSD is a sensitive surrogate marker of raised ICP, but demonstrated poorer specificity. This relationship was more reliable in older children, particularly when the AF was closed. Analysis of the dynamic characteristics of the ONS appeared to provide useful additional information as an independent marker, and may contribute to our overall understanding of ONSD measurement in raised ICP. 2016-02-05T07:24:50Z 2016-02-05T07:24:50Z 2015 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/16787 eng application/pdf Department of Surgery Faculty of Health Sciences University of Cape Town |
| spellingShingle | Neurosurgery Padayachy, Llewellyn Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) |
| thesis_degree_str | Doctoral |
| title | Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) |
| title_full | Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) |
| title_fullStr | Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) |
| title_full_unstemmed | Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) |
| title_short | Ultrasound as a non-invasive diagnostic tool in paediatric neurosurgery : relationship between the optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) |
| title_sort | ultrasound as a non invasive diagnostic tool in paediatric neurosurgery relationship between the optic nerve sheath diameter onsd and intracranial pressure icp |
| topic | Neurosurgery |
| url | http://hdl.handle.net/11427/16787 |
| work_keys_str_mv | AT padayachyllewellyn ultrasoundasanoninvasivediagnostictoolinpaediatricneurosurgeryrelationshipbetweentheopticnervesheathdiameteronsdandintracranialpressureicp |