Role of the optic nerve sheath diameter in the assessment of the effectiveness of decompressive surgery after malignant middle cerebral artery infarction

Invasive and Noninvasive Techniques for Intracranial Pressure Monitoring After Decompressive Craniectomy: A Systematic Review and Meta-Analysis

The use of invasive or noninvasive intracranial pressure (ICP) monitoring post-decompressive craniectomy (DC) has been a continuous matter of debate. Accordingly, this meta-analysis aims to examine the existing evidence of both approaches and compare their impact among patients undergoing DC, guiding clinical decision-making in the management of elevated ICP. The databases used were Pubmed, Cochrane, Web of Science, and Embase. Inclusion criteria included: (1) English studies; (2) randomized and nonrandomized studies; (3) reporting on invasive OR noninvasive ICP monitoring after DC; (4) with at least one of the outcomes of interest: incidence of mortality, new cerebral hemorrhages, and the Glasgow Outcome Scale. The study followed the Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Thirty-six studies were included in this meta-analysis, resulting in a sample of 1624 patients. One thousand two hundred eighty-six underwent invasive monitoring, and 338 underwent noninvasive methods. In the invasive group, a mortality rate of 17% (95% confidence interval [CI]: 12%-22%), a good outcome rate of 58% (95% CI: 38%-49%), a poor outcome rate of 42% (95% CI: 21%-62%), and an overall incidence of new hemorrhages of 4% (95% CI: 0%-8%) were found. Whereas in the noninvasive sample, a mortality rate of 20% (95% CI: 15%-26%) and a good outcome rate of 38% (95% CI: 25%-52%) were obtained. It seems that the effectiveness of invasive and noninvasive ICP monitoring methods are comparable in post-DC patients. While invasive monitoring remains gold standard, noninvasive methods offer a safer and cost-effective alternative, potentially improving post-DC patient care, and can mostly be used simultaneously with invasive methods.

Effect of General Anesthesia on MR Optic Nerve Sheath Diameter in the Pediatric Population

BACKGROUND

Papilledema is thought to be the hallmark sign of increased intracranial pressure (ICP). Distension of the subarachnoid space within the optic nerve sheath is also commonly reported in MR studies as an indirect sign of increased ICP.

HYPOTHESIS

General anesthesia and positive pressure ventilation might result in changes in optic sheath diameter (OSD) observed on clinical brain MRI.

STUDY TYPE

Retrospective.

POPULATION

One hundred forty-five  patients (154 MRI scans, 7.3 years ± 5.1); 97 studies in the anesthesia group (4.4 years ± 3.4) of which 22 had papilledema, and 57 in the non-anesthesia group (12.3 years ± 3.2), of which 28 had papilledema.

FIELD STRENGTH/SEQUENCE

1.5T or 3.0T volumetric T2 images. T2 images were obtained from different vendors.

ASSESSMENT

OSD, optic nerve diameter (OND), and peri-optic cerebrospinal fluid (CSF) were measured manually on T2-weighted MR images for various population subgroups (with and without anesthesia; with or without papilledema). The correlation between these measurements and the clinical diagnosis of papilledema was evaluated via receiver operating characteristic (ROC) analysis.

STATISTICAL TESTS

Chi-square test; Mann-Whitney Test; Spearman's test and ROCs; Interclass correlation coefficient, P = 0.05.

RESULTS

General anesthesia resulted in significantly larger mean OSD in patients with or without papilledema (7.3 ± 1.0 mm vs. 6.1 ± 1.1 mm and 6.7 ± 1.0 mm vs. 5.4 ± 0.9 mm, respectively). In the non-anesthesia group, the average OSD values (6.1 ± 1.1 mm) were significantly higher in papilledema patients compared to non-papilledema patients (5.4 ± 0.9 mm), with larger peri-optic CSF rim (1.6 ± 0.4 mm vs. 1.3 ± 0.3 mm). In the anesthesia group, OND was significantly larger in papilledema patients (3.4 ± 0.4 mm vs. 3.1 ± 0.5 mm), though the average peri-optic CSF rim did not reach a significance in papilledema compared with non-papilledema patients (2.0 ± 0.3 mm vs. 1.8 ± 0.4 mm, P = 0.06). In patients with general anesthesia, peri-optic CSF rim had a limited correlation with increased ICP.

DATA CONCLUSION

In the pediatric population, imaging findings of increased OSD on brain MRI might be related to general anesthesia rather than increased ICP. The interpretation of optic nerve sheath distention should be reported cautiously in conjunction with anesthesia status, especially in the pediatric population.

EVIDENCE LEVEL

4 Technical Efficacy: 5.