Journal club opic nerve sheath diameter

Department of Neurosurgery
Tribhuvan University Teaching Hospital
Journal club
Presenter- Sandesh Dahal, MCh resident
Date- 7th October, 2020
INTRODUCTION

INTRODUCTION

 Published in- BMC Neurology (2020) 20:354
 Link page- https://doi.org/10.1186/s12883-020-01931-w
 Impact factor- 2.350
 Published year- 22nd sept, 2020
INTRODUCTION

Background
 Decompressive hemicraniectomy (DHC) can save lives from malignant MCA
infarction.
 Some studies claim it improves functional outcomes as well.
 But all the studies to date have enrolled the patients after 12 hours of presentation.
 They have excluded the patients who have undergone endovascular therapy.
INTRODUCTION

 But DHC is not without risk.
 It has its own morbidity and mortality.
 Some study claim, DHC increases survival at the cost of increasing morbidity and
poor functional outcome.
 Different clinical and radiological parameters studied to predict the malignant
progression.
INTRODUCTION

 The predictors are,
 clinical parameters,
 initial infarct volume on DWI,
 Imaging, especially midline shift (MLS) in CT scan.
 ICP monitor has been employed in such conditions in trauma cases.
 ICP monitor in malignant anterior cerebral infarction has been inconsistent.
INTRODUCTION

 So, there is need of dynamic parameter in predicting the progression in these patients.
 Optic nerve sheath diameter (ONSD) and ONSD to ETD ratio (eye transverse
diameter) can be useful bedside predictor to asses the progression of these patients.
INTRODUCTION

 The principle is, the optic nerve subarachnoid space communicates with that of
chiasmatic cistern.
 Any increase in ICP transmits this pressure into the optic nerve causing its
enlargement.
 So, it is presumed to be a good dynamic parameter to asses ICP.
 The data need to be validated in the setting of huge anterior circulation infarction.
INTRODUCTION

Methods
 Retrospective single center study.
 Study period- January, 2010 to October, 2017.
 Study center- Department of Neurology, Ajou University School of Medicine, South
Korea.
Methodology

Method…
 Inclusion criteria
 Acute anterior circulation infarction DWI volume>82ml
 Presentation within 6 hours of presentation
 NIHSS score of >= 15.
 Exclusion criteria
 Significant contralateral stroke
Methodology

 Stroke management
 Intravascular therapy as per physician’s decision
 All patients underwent CT scan on presentation, CT angiography, and CT scan
on the following day.
 Medical Management of ICP as per hospital protocol.
 Use of osmolar therapy and hypothermia as per hospital protocol.
Methodology

 Classification CT time-points
 Siemens 128 slice CT scan
 5 mm axial cuts at 120 kv, 200mAs.
 CT done during arrival= CTbaseline
 CT done after angiography or endovascular procedure= CTpostprocedure
 CT done the following day= CTD1
Methodology

Malignant progression and DHC
 Done on the basis of clinical signs.
 Signs
 altered mental status,
 flexor or extensor motor posturing,
 pupillary abnormality,
 respiratory pattern changes,
 eye movement impairments, or
 respiratory pattern abnormalities
Methodology

 Those signs with CT features of impending herniation were classified as malignant
progressors.
 Malignant progressors were classified as
 Early- those occurring before CTD1
 Late- those occurring after CTD1
 DHC was done regardless of the age and whether thrombolysis done.
 ONSD was not used for clinical decision making.
Methodology

 CT scan were interpreted using commercial CT viewing software.
 ONSD/ETD measures in chest abdomen window, with five fold magnification.
 ONSD was measured at 3 mm from the retina perpendicular to the long axis of optic
nerve.
 ETD was calculated as max transverse diameter from retina to retina.
 All calculations made bilaterally and averaged.
Methodology

Methodology

 MLS was measured in the same CT scan.
 MLS calculated was displacement of septum pellucidum from midline.
 To minimize bias, all the reading were taken two weeks apart.
 Post-procedural hemorrhagic complications were classified in accordance with the
European Cooperative Acute Stroke Study criteria.
Methodology

ECASS criteria
Methodology

Statistical analysis
 The patients were grouped in two categories based on malignant progression.
 Difference in clinical characters analyzed between the two groups.
 CT difference between two groups were analyzed.
Statisticalanalysis

 longitudinal analysis of MLS and ONSD/ETD done.
 linear mixed-effects model to estimate mean levels of the parameters over time
within groups from baseline to D1 of follow-up, using available data done.
 The fixed effects were CT time points.
 Group and group-by time interaction effect and individual was included as a random
effect.
Statisticalanalysis

 For imaging analysis of the CTpostprocedure time point, both MLS changes and
ONSD/ETD changes adjusted for time by hours from CTbaseline to CTpostprocedure to
account for time based changes.
 Multivariate analysis done to confirm the clinical significance of time corrected
changes in ONSD/ETD and MLS in prediction of early malignant progression.
Statisticalanalysis

 In the CTD1 time point, both MLS changes and ONSD/ETD changes were adjusted
for time by days from CTbaseline to CTD1 to account for time based changes.
 Multivariate analysis done to confirm the clinical significance of time corrected
changes in ONSD/ETD and MLS in prediction of late malignant progression.
Statisticalanalysis

 The data are presented as the mean ± standard deviation or as the median
[interquartile range].
 A P-value less than 0.05 was considered statistically significant.
 Statistical analyses were performed using IBM SPSS Statistics software version 25.
 R software, version 3.6.2. (R Foundation for Statistical Computing, Vienna, Austria).
Statisticalanalysis

Results
39
12
7
Progression number of patients
non pregression early progression late progression
Total patients= 58
Results

Results

Baseline characters in two groups
Results

CT characters in two groups
Results

Results summary
 About 1/3rd patients had malignant progression.
 Those with malignant progression had worse outcome.
 Complex T shape occlusion was associated with malignant progression.
 One third of those going deterioration, went in late deterioration.
Results

 Factors significant for early deterioration are
 DWI infarct volume
 Those undergoing endovascular treatment
 Complex T type occlusion
 Hemorrhagic conversion
 Midline shift
 ONSD/ETD could not predict early deterioration from admission to angiography or
endovascular time.
Results

 Late progression
 Initial infarct volume does not correlate
 Hemorrhagic pattern also does not correlate
 Predicted by
 MLS in mm/day
 Change in ONSD/ETD ratio in %/day
Results

Discussion
 This study shows increase in ONSD/ETD ration from baseline to CTD1 correlates
with the malignant progression.
 Rate of change from baseline was significant predictor of late progression.
 Rate of change of MLS was predictor of malignant progression in both early and late
progression.
Discussion

 This non-invasive method can be equivalent to invasive ICP monitoring that is
done in trauma settings.
 ICP also changes with posture and procedures that cause pain.
 Similar things might have interfered the measurement of ONSD in the initial
time point.
 So, ONSD evaluation should be best done after stabilization.
Discussion

 ICP monitors used to assess ICP previously but inconsistent results, normal ICP on
sensor with brainstem compression, pupillary changes and evidence of herniation on
CT scan.
Discussion

 The current study may advocate CT or USG guided monitoring of the ONSD to
evaluate the malignant progression of infarction.
 Further prospective studies needed to confirm the results though.
Discussion

Discussion

Conclusion
 In acute stroke patients with malignant infarct cores, an increase in ONSD/ETD ratio
compared to baseline increases the odds of malignant progression, and may be used
as a marker for emergent therapeutic interventions.
Conclusion

Critical appraisal
 Strength
 CT protocol and criteria well defined.
 Patients presented earlier than12 hours included.
 Patients undergone endovascular therapy and hemorrhagic transformation
included.
Criticalappraisal

 Weakness
 Single center
 Retrospective
 Small sample size, inadequate for drawing conclusions and more so for sub-
group analysis.
 Poor outcome in DHC group, and all patients in malignant transformation has
undergone endovascular therapy. Separate analysis has not been done.
Criticalappraisal

 Admission status (GCS) except radiology unknown.
 Endovascular therapy and complication details not available. Angiography and
intervention given same gravity in data analysis.
 Eloquence of the infarction site not mentioned.
Criticalappraisal

Take home message
 ONSD is simple, easy and non invasive method of assessment.
 It correlates well with raised ICP.
 It’s a dynamic measurement.
 It may have very useful implications for prognostication as well as guiding the therapy in
ICU patients in trauma as well as non trauma settings, where imaging is risky and
cumbersome to do.
 Further validation with prospective study is helpful to guide its use for the neuro-critical
patients.
Takehomemessage

Thank you

Journal club opic nerve sheath diameter

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