Polyetheretherketone has become one of the most important material choices for cranioplasty surgery. It has been shown that conventional ultrasound can be performed through the polyetheretherketone material for the examination of brain tissue and ventricular morphology. Transcranial doppler ultrasound can obtain good images of cerebral hemodynamic parameters in patients through polyetheretherketone-covered temporal window. This trial is a clinical prospective observational study in which cases treated with polyetheretherketone cranioplasty, and transcranial doppler ultrasonography is performed preoperatively and 10 days postoperatively, and data were collected mainly including bilateral hemodynamic parameters of middle cerebral artery(MCA), terminal internal carotid artery(TICA), (anterior communicating artery)ACA, and posterior cerebral artery(PCA) (Vs, Vd, Vm, PI index, RI index) from temporal window.

Inclusion Criteria:

1. Age of 18 years or older;
2. Proposed polyetheretherketone cranioplasty;
3. Incomplete cranial bone in the lateral temporal window;
4. Signed informed consent for surgery and informed consent for research.

Exclusion Criteria:

1)Although cranioplasty is proposed, the cranial bone in the temporal region is intact.

1. Age of 18 years or older;
2. Proposed polyetheretherketone cranioplasty;
3. Incomplete cranial bone in the lateral temporal window.