Original Article: PDF OnlyElective Sonolucent Cranioplasty for Real-Time Ultrasound Monitoring of Flow and Patency of an Extra- to Intracranial BypassHadley, Caroline MD; North, Robert MD; Srinivasan, Visish MD; Kan, Peter MD; Burkhardt, Jan-Karl MDAuthor Information Department of Neurosurgery, Baylor College of Medicine, Houston, TX. Address correspondence and reprint requests to Jan-Karl Burkhardt, MD, Department of Neurosurgery, Baylor College of Medicine Medical Center, 7200 Cambridge Street, Suite 9B, Houston, TX, 77030; E-Mail: Jan-Karl.Burkhardt@bcm.edu Received 12 November, 2019 Accepted 17 November, 2019 The authors have no conflicts of interest to disclose. This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0 Journal of Craniofacial Surgery: March 06, 2020 - Volume Publish Ahead of Print - Issue - doi: 10.1097/SCS.0000000000006225 Open PAP Metrics Abstract Cross-sectional imaging studies or catheter angiogram are the imaging modalities of choice to evaluate bypass patency after extra- to intracranial (EC-IC) bypass surgery. Although providing accurate results, these imaging modalities are time-consuming and/or present radiation risk for the patient. Ultrasound imaging is a fast and widely available imaging modality, but is limited in this setting due to the non-sonolucent autologous bone flap covering the bypass after surgery. The recently FDA approved clear polymethyl methacrylate (PMMA) cranioplasty implant overcomes this limitation by its sonolucent characteristic, but has not yet been used in the setting of EC-IC bypass surgery. Here, the authors describe for the first time the feasibility of an elective sonolucent cranioplasty to monitor flow and patency of an EC-IC bypass in real time using ultrasound. This moyamoya patient underwent a direct superficial temporal artery to middle cerebral artery (STA-MCA) bypass, after which a PMMA implant was used to close the craniotomy defect, instead of reimplanting the autologous bone flap. Immediate postoperative bedside transcranioplasty ultrasound confirmed bypass patency and allowed for quantitative flow measurements as well as for exclusion of postoperative hemorrhage. Postoperative CTA and catheter angiogram confirmed patency of the bypass without complications. This report shows for the first time that this technique is feasible and permits bedside transcranioplasty ultrasound assessment of bypass flow in real time, confirmed with angiography. This technique may permit easy comparison of baseline findings with follow up assessments and facilitate less invasive monitoring of bypass patency. © 2020 by Mutaz B. Habal, MD.