Letter to the Editor. Ultrasonography of the optic nerve sheath and decompressive craniectomy

Free access

If the inline PDF is not rendering correctly, you can download the PDF file here.

TO THE EDITOR: The evaluation of the elevation of intracranial pressure is a relevant issue during the management of patients with traumatic brain injury (TBI). We read the interesting article by Wang et al.10 in which the authors share their experience with ultrasonography to measure the optic nerve sheath diameter, which they correlate with intracranial pressure (ICP), and identify the process as an accurate noninvasive method in patients with decompressive craniotomy (Wang J, Li K, Li H, et al: Ultrasonographic optic nerve sheath diameter correlation with ICP and accuracy as a tool for noninvasive surrogate ICP measurement in patients with decompressive craniotomy. J Neurosurg [epub ahead of print July 19, 2019. DOI: 10.3171/2019.4.JNS183297]).

We have some questions that must be clarified to extrapolate and validate their results. First of all, the authors report that the patients underwent decompressive craniectomy without defining the surgical technique. Why is this topic important? It has been established that the size of the craniectomy influences ICP values in the postoperative period.7 It would be interesting to know the details of the surgical technique as this would add to the validity of the results and thus reduce the bias related to the inclusion of patients.

Interestingly, several studies have demonstrated the relevance of evaluating the optic nerve for early detection of intracranial hypertension.4,6 These studies are not extrapolated to the general population; cohorts of specific populations are required. Acting as a confounding factor to establish the normal diameter of the optic nerve sheath, ethnicity also needs to be carefully evaluated. Ethnicity can limit interpretation of the results and their applicability in daily practice.2,8

The laterality of the lesion and its correlation with the elevation of the optic nerve sheath diameter are other relevant aspects. This is not reported in the data presented by the authors. Multiple studies have reported these findings and it would be interesting to know if this was evaluated in the study.1,3,5

Compartmentalization of the ICP is another relevant aspect.9 It has been established that the parenchymal ICP measurement corresponds to the evaluation of a local parameter indicative of a regional phenomenon and that evaluation with the intraventricular catheter would be more useful than that with intraparenchymal monitors. What was the reason for not using intraventricular ICP monitoring in the authors’ study? On the other hand, the heterogeneity of brain injury should be taken into account, and the authors included heterogeneous intracranial lesions (acute subdural hematoma, acute intracerebral hematoma, cerebral contusion/laceration, and diffuse brain injury), which can alter the results.

Finally, given the potential benefits of the application of optic nerve ultrasound in patients with TBI and especially in those undergoing decompressive craniectomy, we suggest conducting studies in specific populations and multicentric studies to compare results that are relevant in the management of these patients. We congratulate the authors on their study despite the potential limitations.

Disclosures

The authors report no conflict of interest.

References

  • 1

    Frumin ESchlang JWiechmann WHata SRosen SAnderson C: Prospective analysis of single operator sonographic optic nerve sheath diameter measurement for diagnosis of elevated intracranial pressure. West J Emerg Med 15:2172202014

    • Search Google Scholar
    • Export Citation
  • 2

    Goeres PZeiler FAUnger BKarakitsos DGillman LM: Ultrasound assessment of optic nerve sheath diameter in healthy volunteers. J Crit Care 31:1681712016

    • Search Google Scholar
    • Export Citation
  • 3

    Golshani KEbrahim Zadeh MFarajzadegan ZKhorvash F: Diagnostic accuracy of optic nerve ultrasonography and ophthalmoscopy in prediction of elevated intracranial pressure. Emerg (Tehran) 3:54582015

    • Search Google Scholar
    • Export Citation
  • 4

    Kimberly HHShah SMarill KNoble V: Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 15:2012042008

    • Search Google Scholar
    • Export Citation
  • 5

    Roque PJWu TSBarth LDrachman DKhor KNLovecchio F: Optic nerve ultrasound for the detection of elevated intracranial pressure in the hypertensive patient. Am J Emerg Med 30:135713632012

    • Search Google Scholar
    • Export Citation
  • 6

    Rosenberg JBShiloh ALSavel RHEisen LA: Non-invasive methods of estimating intracranial pressure. Neurocrit Care 15:5996082011

    • Search Google Scholar
    • Export Citation
  • 7

    Skoglund TSEriksson-Ritzén CJensen CRydenhag B: Aspects on decompressive craniectomy in patients with traumatic head injuries. J Neurotrauma 23:150215092006

    • Search Google Scholar
    • Export Citation
  • 8

    Soldatos TKarakitsos DChatzimichail KPapathanasiou MGouliamos AKarabinis A: Optic nerve sonography in the diagnostic evaluation of adult brain injury. Crit Care 12:R672008

    • Search Google Scholar
    • Export Citation
  • 9

    Vender JWaller JDhandapani KMcDonnell D: An evaluation and comparison of intraventricular, intraparenchymal, and fluid-coupled techniques for intracranial pressure monitoring in patients with severe traumatic brain injury. J Clin Monit Comput 25:2312362011

    • Search Google Scholar
    • Export Citation
  • 10

    Wang JLi KLi HJi CWu ZChen H: Ultrasonographic optic nerve sheath diameter correlation with ICP and accuracy as a tool for noninvasive surrogate ICP measurement in patients with decompressive craniotomy. J Neurosurg [epub ahead of print July 19 2019. DOI: 10.3171/2019.4.JNS183297]

    • Search Google Scholar
    • Export Citation
Keywords:

Response

We are grateful to Drs. Moscote-Salazar, Joaquim, and Agrawal for their interest and insightful comments regarding our article. Their first question relates to the surgical technique and the size of the craniotomy, both of which may influence ICP. A larger craniotomy produced a larger decrease in ICP8 in patients with TBI. The area of the bone window was approximately 12 × 15 cm in unilateral decompressive craniotomy (DC) and about double 12 × 15 cm in bilateral and frontal DC in our unit. The dura mater or artificial dura substitutes loosely covered the brain surface. Three patients with diffuse brain injury underwent bilateral or frontal DC among the 48 TBI patients potentially eligible for our study, and 2 died within 24 hours after DC. Among the 35 ultimately enrolled patients, 1 underwent bilateral and 34 underwent unilateral DC. We did not exclude a bilateral DC patient who had mildly elevated ICP.

The second question relates to optic nerve sheath diameter (ONSD) of the general population and ethnicity. Healthy volunteers who met the physical examination criteria underwent ultrasound examination in a calm state, and their ICP was considered normal. These volunteers provided written informed consent before ONSD examination.2

We agree that the laterality of the lesion influences the value of the ONSD. When ONSD measurements were performed, the operator did not find obvious differences in the ONSDs between the two eyes except in orbital injury, which was an exclusion criterion. We just compared the mean differences in left and right ONSDs, which were 0.31 ± 0.05 mm and 0.27 ± 0.03 mm in healthy volunteers and TBI patients, respectively (p = 0.53). The mean ONSD value was considered in the statistical analysis in this study. Both single (left/right)6 and mean values of ONSD7 were used as the parameters in different studies.

The other relevant aspect is compartmentalization of the ICP. External ventricular drainage (EVD) for ICP monitoring was considered as the gold standard for assessing ICP.4 Insertion of an EVD is not always possible when brain swelling causes shift or compression of the ventricles in severe TBI patients.1 While the Codman MicroSensor for ICP monitoring has good concordance with the EVD5 and the MicroSensor ICP is highly accurate and stable in the tissue and subdural space,3 we implanted a MicroSensor transducer into the subdural space to monitor ICP in our unit. Heterogeneity of brain injury definitely influences the ICP values, but this may not affect the correlation between ICP and ONSD.

The aim of this study was to assess the association between ONSD and ICP in TBI patients after a DC operation. There were lots of factors influencing the ICP, such as the surgical technique, the size of craniectomy,8 and the heterogeneity of brain injury. We intend to evaluate the impact factors of ICP and ONSD by expanding the sample size and optimizing the study design in the future. We thank Drs. Moscote-Salazar, Joaquim, and Agrawal for pointing out these important issues, and we wish to cooperate with them in the future.

References

  • 1

    Bhatia AGupta AK: Neuromonitoring in the intensive care unit. I. Intracranial pressure and cerebral blood flow monitoring. Intensive Care Med 33:126312712007

    • Search Google Scholar
    • Export Citation
  • 2

    Chen HDing GSZhao YCYu RGZhou JX: Ultrasound measurement of optic nerve diameter and optic nerve sheath diameter in healthy Chinese adults. BMC Neurol 15:1062015

    • Search Google Scholar
    • Export Citation
  • 3

    Gray WPPalmer JDGill JGardner MIannotti F: A clinical study of parenchymal and subdural miniature strain-gauge transducers for monitoring intracranial pressure. Neurosurgery 39:9279321996

    • Search Google Scholar
    • Export Citation
  • 4

    Harary MDolmans RGFGormley WB: Intracranial pressure monitoring—review and avenues for development. Sensors (Basel) 18:E4652018

  • 5

    Koskinen LOOlivecrona M: Clinical experience with the intraparenchymal intracranial pressure monitoring Codman MicroSensor system. Neurosurgery 56:6936982005

    • Search Google Scholar
    • Export Citation
  • 6

    Maissan IMDirven PJHaitsma IKHoeks SEGommers DStolker RJ: Ultrasonographic measured optic nerve sheath diameter as an accurate and quick monitor for changes in intracranial pressure. J Neurosurg 123:7437472015

    • Search Google Scholar
    • Export Citation
  • 7

    Robba CDonnelly JCardim DTajsic TCabeleira MCiterio G: Optic nerve sheath diameter ultrasonography at admission as a predictor of intracranial hypertension in traumatic brain injured patients: a prospective observational study. J Neurosurg [epub ahead of print March 8 2019. DOI: 10.3171/2018.11.JNS182077]

    • Search Google Scholar
    • Export Citation
  • 8

    Skoglund TSEriksson-Ritzén CJensen CRydenhag B: Aspects on decompressive craniectomy in patients with traumatic head injuries. J Neurotrauma 23:150215092006

    • Search Google Scholar
    • Export Citation

If the inline PDF is not rendering correctly, you can download the PDF file here.

Article Information

Contributor Notes

Correspondence Luis Rafael Moscote-Salazar: rafaelmoscote21@gmail.com.INCLUDE WHEN CITING Published online November 22, 2019; DOI: 10.3171/2019.8.JNS192114.Disclosures The authors report no conflict of interest.
Headings
References
  • 1

    Frumin ESchlang JWiechmann WHata SRosen SAnderson C: Prospective analysis of single operator sonographic optic nerve sheath diameter measurement for diagnosis of elevated intracranial pressure. West J Emerg Med 15:2172202014

    • Search Google Scholar
    • Export Citation
  • 2

    Goeres PZeiler FAUnger BKarakitsos DGillman LM: Ultrasound assessment of optic nerve sheath diameter in healthy volunteers. J Crit Care 31:1681712016

    • Search Google Scholar
    • Export Citation
  • 3

    Golshani KEbrahim Zadeh MFarajzadegan ZKhorvash F: Diagnostic accuracy of optic nerve ultrasonography and ophthalmoscopy in prediction of elevated intracranial pressure. Emerg (Tehran) 3:54582015

    • Search Google Scholar
    • Export Citation
  • 4

    Kimberly HHShah SMarill KNoble V: Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 15:2012042008

    • Search Google Scholar
    • Export Citation
  • 5

    Roque PJWu TSBarth LDrachman DKhor KNLovecchio F: Optic nerve ultrasound for the detection of elevated intracranial pressure in the hypertensive patient. Am J Emerg Med 30:135713632012

    • Search Google Scholar
    • Export Citation
  • 6

    Rosenberg JBShiloh ALSavel RHEisen LA: Non-invasive methods of estimating intracranial pressure. Neurocrit Care 15:5996082011

    • Search Google Scholar
    • Export Citation
  • 7

    Skoglund TSEriksson-Ritzén CJensen CRydenhag B: Aspects on decompressive craniectomy in patients with traumatic head injuries. J Neurotrauma 23:150215092006

    • Search Google Scholar
    • Export Citation
  • 8

    Soldatos TKarakitsos DChatzimichail KPapathanasiou MGouliamos AKarabinis A: Optic nerve sonography in the diagnostic evaluation of adult brain injury. Crit Care 12:R672008

    • Search Google Scholar
    • Export Citation
  • 9

    Vender JWaller JDhandapani KMcDonnell D: An evaluation and comparison of intraventricular, intraparenchymal, and fluid-coupled techniques for intracranial pressure monitoring in patients with severe traumatic brain injury. J Clin Monit Comput 25:2312362011

    • Search Google Scholar
    • Export Citation
  • 10

    Wang JLi KLi HJi CWu ZChen H: Ultrasonographic optic nerve sheath diameter correlation with ICP and accuracy as a tool for noninvasive surrogate ICP measurement in patients with decompressive craniotomy. J Neurosurg [epub ahead of print July 19 2019. DOI: 10.3171/2019.4.JNS183297]

    • Search Google Scholar
    • Export Citation
  • 1

    Bhatia AGupta AK: Neuromonitoring in the intensive care unit. I. Intracranial pressure and cerebral blood flow monitoring. Intensive Care Med 33:126312712007

    • Search Google Scholar
    • Export Citation
  • 2

    Chen HDing GSZhao YCYu RGZhou JX: Ultrasound measurement of optic nerve diameter and optic nerve sheath diameter in healthy Chinese adults. BMC Neurol 15:1062015

    • Search Google Scholar
    • Export Citation
  • 3

    Gray WPPalmer JDGill JGardner MIannotti F: A clinical study of parenchymal and subdural miniature strain-gauge transducers for monitoring intracranial pressure. Neurosurgery 39:9279321996

    • Search Google Scholar
    • Export Citation
  • 4

    Harary MDolmans RGFGormley WB: Intracranial pressure monitoring—review and avenues for development. Sensors (Basel) 18:E4652018

  • 5

    Koskinen LOOlivecrona M: Clinical experience with the intraparenchymal intracranial pressure monitoring Codman MicroSensor system. Neurosurgery 56:6936982005

    • Search Google Scholar
    • Export Citation
  • 6

    Maissan IMDirven PJHaitsma IKHoeks SEGommers DStolker RJ: Ultrasonographic measured optic nerve sheath diameter as an accurate and quick monitor for changes in intracranial pressure. J Neurosurg 123:7437472015

    • Search Google Scholar
    • Export Citation
  • 7

    Robba CDonnelly JCardim DTajsic TCabeleira MCiterio G: Optic nerve sheath diameter ultrasonography at admission as a predictor of intracranial hypertension in traumatic brain injured patients: a prospective observational study. J Neurosurg [epub ahead of print March 8 2019. DOI: 10.3171/2018.11.JNS182077]

    • Search Google Scholar
    • Export Citation
  • 8

    Skoglund TSEriksson-Ritzén CJensen CRydenhag B: Aspects on decompressive craniectomy in patients with traumatic head injuries. J Neurotrauma 23:150215092006

    • Search Google Scholar
    • Export Citation
TrendMD
Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 202 202 202
PDF Downloads 14 14 14
EPUB Downloads 0 0 0
PubMed
Google Scholar