Fig. 1

Monitoring of middle cerebral artery blood flows of 28 patients included in the study. a Preoperative CT images of a 40-year male patient shows the presence of SDH in the right brain, disappearance of bilateral basal cisterns (black arrows) and a midline shift of 12 mm (yellow line). b When standard DC was performed, the skin was first incised at Kocher’s point (black arrow). A cranial burr hole was then created and puncturing was performed in the direction of the given sagittal plane (white arrow) to puncture the frontal horn of the ventricular system for the acquisition of ICP data. In this case, the measured ICP was 46.2 mmHg. Severe brain bulge occurred 15 min after the intraoperative cutting of the dura mater, with brain tissue protruding more than 4 cm beyond the bone window. The yellow arrow indicates the cranial hole used for the implantation of the ICP probe. c After emergency closure of the cranial cavity, a CT re-examination revealed the presence of brain bulge beyond the bone window, complete disappearance of the basal cistern and ventricle (black arrows), and accurate positioning of the ICP probe in the ventricle (red arrow). d Before making the scalp incision, the middle cerebral artery blood flow was monitored through the temporal window, and the values of relevant haemodynamic parameters were recorded. e Scatter plot and correlation analysis of preoperative ICP and PI/RI values of middle cerebral artery flow on the SDH side of the 28 TBI patients. PI = 0.05035 × ICP − 0.02721, r = 0.9316, P < 0.0001, n = 28. RI = 0.009002 × ICP + 0.3338, r = 0.8338, P < 0.0001, n = 28. CT: computer tomography; DC: decompressive craniectomy; ICP: intracranial pressure; PI: pulsatility index; RI: resistance index; SDH: subdural haematoma; TBI: traumatic brain injury