Sonographic monitoring of midline shift in hemispheric infarctions

Background and objective: Transcranial color-coded sonography (TS) allows a noninvasive, accurate evaluation of lateral displacement of the third vent ricle. The authors studied the prognostic value of TS monitoring of the mid line shift (MLS) in acute hemispheric stroke. Method: Sixteen patients with acute middle cerebral artery (MCA) occlusion were investigated. On admissi on, the median modified Scandinavian Stroke Scale (mSSS) score was 6.0 (ran ge, 5 to 8). Five patients died from cerebral herniation (group 1), 10 surv ived (group 2), and 1 patient (Patient 16) survived after decompressive sur gery. TS was performed on days 1 to 4 (10 +/- 3, 32 +/- 4, 57 +/- 5, and 82 +/- 5 hours after onset of symptoms). Distance from the TS probe to the ce nter of the third ventricle was measured both from the symptomatic (A) and asymptomatic (B) sides. MLS was calculated using the formula MLS = (A - B)/ 2. Results: Ten hours after stroke onset, MLS and mSSS scores were not sign ificantly different between the two groups. At 32, 57, and 82 hours, MLS wa s higher in group 1 (32 hours, p = 0.001; 57 hours, p = 0.003; 82 hours, p = 0.023) whereas there was no difference in mSSS score after 32 hours. All patients with an MLS < 4 mm at 32 hours survived, whereas patients with an MLS > 4 mm died as a result of cerebral herniation, with the exception of t he one patient who underwent decompressive hemicraniectomy. Conclusions: Th e study of MLS at 32 hours after stroke onset in patients with severe MCA i nfarctions may identify patients who are unlikely to survive. The value of MLS in determining the indication of decompressive craniectomy merits furth er study.