Safety, Feasibility, and Patient-Rated Outcome of Sonolucent Cranioplasty in Extracranial-Intracranial Bypass Surgery to Allow for Transcranioplasty Ultrasound Assessment

Abstract

Objective We sought to analyze the safety and feasibility of elective sonolucent cranioplasty in the setting of extracranial-to-intracranial (EC-IC) bypass surgery to monitor bypass patency using ultrasound. Methods Patients who underwent direct EC-IC bypass surgery agreed to sonolucent cranioplasty at the time of surgery and received a sonolucent polymethyl methacrylate (PMMA) implant. Besides monitoring clinical outcome, all patients received transcranioplasty ultrasound (TCUS) on postoperative day 1 and at last follow-up. In addition, bypass patency was confirmed using catheter angiogram and fit of implant using computed tomography. Patient-rated outcome was assessed through phone questionnaire. Results EC-IC bypass surgery with PMMA cranioplasty was successful in all 7 patients with patent bypasses on postoperative angiogram. Direct TCUS was feasible in all patients, and bypass patency was monitored. There were no complications such as postoperative hemorrhagic/ischemic complications related to the bypass procedure in this patient population, as well as no complications related to the PMMA implant. Postoperative computed tomography showed favorable cosmetic results of the PMMA implant in both the pterional area for superficial temporal artery−middle cerebral artery bypasses and parietooccipital area for occipital artery−middle cerebral artery bypasses as confirmed by high-rated overall patient satisfaction with favorable cosmetic, pain, and sensory patient-rated outcomes. Conclusions In this study we were able to show that this novel technique is safe, allows for patency assessment of the EC-IC bypass using bedside TCUS technique, and is cosmetically satisfying for patients.

Ultrasounds induce blood–brain barrier opening across a sonolucent polyolefin plate in an in vitro isolated brain preparation

“…The presented findings represent the necessary preliminary step to propose polyolefin-based material as US-permeable skull prostheses to be used for repetitive BBB openings in a clinical setting. The concept of implanting sonolucent cranioplasties for imaging purposes has already been fostered by various authors 27 – 29 ; most recently, two articles were published by Jan-Karl Burkhardt’s group proposing such concept to be exploited in the follow-up of intracranial bypasses with satisfactory safety and efficacy 30 , 31 . However, only one article from 1987 had theorized the implantation of US-permeable cranioplasty materials for TUS purposes: Tobias and collaborators already proposed US-based ablative treatments to be performed across a sonolucent window to preserve the mechanical protection of the skull while allowing full penetration of the US waves 32 ; in their study, these authors proved that homogenous and low-porosity materials cause the least attenuation and distortion of the incident beam.…”

Neuroimaging through Sonolucent Cranioplasty: A Systematic Scoping Review Protocol

“…Altogether, this review will identify current evidence and gaps in knowledge on SC to motivate future research. Larger clinical trials are currently ongoing to evaluate TCUS in larger patient populations following extracranial–intracranial bypass, stroke, tumor, and external ventricular drain placement [ 3 , 17 ]. The hope is for this review to motivate controlled, quantitative data-focused clinical trials, which would enhance the likelihood that clinicians consider using sonolucent materials to perform cranioplasty.…”

“…However, fontanelle closure makes it impossible to leverage this method as a diagnostic tool in adult neurosurgery [ 2 ]. Sonolucent cranioplasty (SC) implants provide an unprecedented opportunity in adult neurosurgery to conduct neuromonitoring, evaluate hemodynamics, visually track devices located within the implant, and perform focused ultrasound treatments [ 2 , 3 , 4 , 5 , 6 ]. Current research on SC has utilized polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), and polyolefin as sonolucent materials [ 7 , 8 , 9 ].…”

“…Despite a large amount of clinical evidence supporting the use of cranioplasty and the frequency that these surgical procedures are performed, there is a dearth of knowledge about outcomes and risk factors associated with SC. Previous research on SC has been largely limited to proof-of-concept studies and case series [ 3 , 7 , 8 ].…”

Double-barrel STA-MCA bypass for cerebral revascularization: lessons learned from a 10-year experience

“…Bypass flows can be monitored over time using angiography, quantitative MRA, 15 or a novel technique, transcranioplasty Doppler ultrasound. 16,17 In addition to increased flow overall, double-barrel bypass can distribute flow to two at-risk territories to be targeted simultaneously. In steno-occlusive disease, patients often have more than one region of hypoperfusion.…”