“…In most cases Figure 2, no intra-operative complications were reported in the selected studies. We found that there was a higher percentage for certain types of surgery, such as in the case of neurosurgical pathology [16,24,28,29,32], both cranial and spinal [15,18,19,36,42,49]. In some cases, the risk factor for PRES was sustained by hypertension caused by incomplete postoperative pain control [67].…”