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Lu D, Moritz W, Arafa HM, Yang Q, Jacobson L, Ostojich D, Bai W, Guo H, Wu C, Li S, Li S, Huang Y, Xu Y, Yan Y, Westman AM, MacEwan MR, Rogers JA, Pet MA. Intramuscular Microvascular Flow Sensing for Flap Monitoring in a Porcine Model of Arterial and Venous Occlusion. J Reconstr Microsurg 2023; 39:231-237. [PMID: 35952677 DOI: 10.1055/s-0042-1755261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
BACKGROUND Commercially available near infrared spectroscopy devices for continuous free flap tissue oxygenation (StO2) monitoring can only be used on flaps with a cutaneous component. Additionally, differences in skin quality and pigmentation may alter StO2 measurements. Here, we present a novel implantable heat convection probe that measures microvascular blood flow for peripheral monitoring of free flaps, and is not subject to the same issues that limit the clinical utility of near-infrared spectroscopy. METHODS The intratissue microvascular flow-sensing device includes a resistive heater, 4 thermistors, a small battery, and a Bluetooth chip, which allows connection to a smart device. Convection of applied heat is measured and mathematically transformed into a measurement of blood flow velocity. This was tested alongside Vioptix T.Ox in a porcine rectus abdominis myocutaneous flap model of arterial and venous occlusion. After flap elevation, the thermal device was deployed intramuscularly, and the cutaneous T.Ox device was applied. Acland clamps were alternately applied to the flap artery and veins to achieve 15 minutes periods of flap ischemia and congestion with a 15 minutes intervening recovery period. In total, five devices were tested in three flaps in three separate pigs over 16 vaso-occlusive events. RESULTS Flow measurements were responsive to both ischemia and congestion, and returned to baseline during recovery periods. Flow measurements corresponded closely with measured StO2. Cross-correlation at zero lag showed agreement between these two sensing modalities. Two novel devices tested simultaneously on the same flap showed only minor variations in flow measurements. CONCLUSION This novel probe is capable of detecting changes in tissue microcirculatory blood flow. This device performed well in a swine model of flap ischemia and congestion, and shows promise as a potentially useful clinical tool. Future studies will investigate performance in fasciocutaneous flaps and characterize longevity of the device over a period of several days.
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Affiliation(s)
- Di Lu
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - William Moritz
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Hany M Arafa
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Quansan Yang
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Lauren Jacobson
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Diana Ostojich
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Wubin Bai
- Department of Applied Physical Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hexia Guo
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Changsheng Wu
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Shuo Li
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Shupeng Li
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois
| | - Yonggang Huang
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois
| | - Yameng Xu
- Department of Neurosurgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Ying Yan
- Department of Neurosurgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Amanda M Westman
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Matthew R MacEwan
- Department of Neurosurgery, School of Medicine, Washington University, St. Louis, Missouri
| | - John A Rogers
- Center of Bio-Integrated Electronics, Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois
| | - Mitchell A Pet
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
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2
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Malik MS, Akoh JA, Houlberg K. The Use of the Implantable Doppler Probe as a Blood Flow Monitoring Device in Clinical Settings: A Narrative Review of the Evidence. EXP CLIN TRANSPLANT 2023; 21:83-92. [PMID: 36919717 DOI: 10.6002/ect.2022.0349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
OBJECTIVES In the past decade, the implantable Doppler probe has been studied widely as a blood flow-monitoring device in reconstructive and transplant surgical specialities. Its utility as an effective postoperative monitoring technique is still debatable, with no clear guidelines in clinical practice. Here, we mapped the current evidence on the usefulness of the implantable Doppler probe as a blood flow-monitoring device. The objective was to present an up-to-date assessment of the benefits and limitations of using implantable Doppler probes in clinical and experimental clinical settings. MATERIALS AND METHODS We conducted a literature search using the Cochrane Library and Healthcare Databases Advanced Search and using implantable Doppler probe, transplant, graft, and flap as key words. The search yielded 184 studies, with 73 studies included after exclusions. We evaluated, synthesized, and summarized the evidence from the studies in tabular form. RESULTS There is clinical equipoise regarding the effectiveness of implantable Doppler probe as a flow sensing technique. The main reason is the lack of information and gaps in the evidence regarding the benefits and limitations of using implantable Doppler probes in clinical practice. CONCLUSIONS The implantable Doppler probe has the potentialto be used as an adjunctpostoperativeblood flow-monitoring device. However, keeping in view of technical limitations, its signals should be interpreted alongside traditional clinical assessment techniques to determine the patency of microvascular anastomosis. Although evidence in this review will inform clinical practice in transplant and reconstructive surgical specialties, a prospective randomized controlled study with a larger patient cohort is required to evaluate the effectiveness of this probe in clinical settings.
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3
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Xie R, Liu Q, Zhang Y, Guo C, Huang X, Liu M. A wireless infrared thermometry device for postoperative flap monitoring: Proof of concept in a porcine flap model. Int Wound J 2022. [DOI: 10.1111/iwj.14034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 11/16/2022] [Indexed: 12/24/2022] Open
Affiliation(s)
- Ruijie Xie
- Department of Hand & Microsurgery, The Affiliated Nanhua Hospital, Hengyang Medical School University of South China Hengyang PR China
| | - Qianlong Liu
- Department of Hand & Microsurgery, The Affiliated Nanhua Hospital, Hengyang Medical School University of South China Hengyang PR China
| | - Ya Zhang
- Department of Gland Surgery, The Affiliated Nanhua Hospital, Hengyang Medical School University of South China Hengyang PR China
| | - Chengyi Guo
- Department of Hand & Microsurgery, The Affiliated Nanhua Hospital, Hengyang Medical School University of South China Hengyang PR China
| | - Xiongjie Huang
- Department of Hand & Microsurgery, The Affiliated Nanhua Hospital, Hengyang Medical School University of South China Hengyang PR China
| | - Mingjiang Liu
- Department of Hand & Microsurgery, The Affiliated Nanhua Hospital, Hengyang Medical School University of South China Hengyang PR China
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4
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Wu C, Rwei AY, Lee JY, Ouyang W, Jacobson L, Shen H, Luan H, Xu Y, Park JB, Kwak SS, Ni X, Bai W, Franklin D, Li S, Liu Y, Ni X, Westman AM, MacEwan MR, Rogers JA, Pet MA. A Wireless Near-Infrared Spectroscopy Device for Flap Monitoring: Proof of Concept in a Porcine Musculocutaneous Flap Model. J Reconstr Microsurg 2021; 38:96-105. [PMID: 34404105 DOI: 10.1055/s-0041-1732426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Current near-infrared spectroscopy (NIRS)-based systems for continuous flap monitoring are highly sensitive for detecting malperfusion. However, the clinical utility and user experience are limited by the wired connection between the sensor and bedside console. This wire leads to instability of the flap-sensor interface and may cause false alarms. METHODS We present a novel wearable wireless NIRS sensor for continuous fasciocutaneous free flap monitoring. This waterproof silicone-encapsulated Bluetooth-enabled device contains two light-emitting diodes and two photodetectors in addition to a battery sufficient for 5 days of uninterrupted function. This novel device was compared with a ViOptix T.Ox monitor in a porcine rectus abdominus myocutaneous flap model of arterial and venous occlusions. RESULTS Devices were tested in four flaps using three animals. Both devices produced very similar tissue oxygen saturation (StO2) tracings throughout the vascular clamping events, with obvious and parallel changes occurring on arterial clamping, arterial release, venous clamping, and venous release. Small interdevice variations in absolute StO2 value readings and magnitude of change were observed. The normalized cross-correlation at zero lag describing correspondence between the novel NIRS and T.Ox devices was >0.99 in each trial. CONCLUSION The wireless NIRS flap monitor is capable of detecting StO2 changes resultant from arterial vascular occlusive events. In this porcine flap model, the functionality of this novel sensor closely mirrored that of the T.Ox wired platform. This device is waterproof, highly adhesive, skin conforming, and has sufficient battery life to function for 5 days. Clinical testing is necessary to determine if this wireless functionality translates into fewer false-positive alarms and a better user experience.
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Affiliation(s)
- Changsheng Wu
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Alina Y Rwei
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois.,Department of Chemical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Jong Yoon Lee
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois.,Sibel Inc., Evanston, Illinois
| | - Wei Ouyang
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Lauren Jacobson
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Haixu Shen
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois
| | - Haiwen Luan
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Yameng Xu
- Department of Neurosurgery, School of Medicine, Washington University, St. Louis, Missouri
| | | | - Sung Soo Kwak
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Xiaoyue Ni
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Wubin Bai
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois
| | - Daniel Franklin
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Shuo Li
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Yiming Liu
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois
| | - Xinchen Ni
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois
| | - Amanda M Westman
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
| | - Matthew R MacEwan
- Department of Neurosurgery, School of Medicine, Washington University, St. Louis, Missouri
| | - John A Rogers
- Department of Materials Science and Engineering, Querrey Simpson Institute for Bioelectronics, Northwestern University, Chicago, Illinois.,Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois.,Department of Mechanical Engineering, Northwestern University, Evanston, Illinois.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois.,Department of Chemistry, Northwestern University, Evanston, Illinois.,Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Mitchell A Pet
- Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Washington University, St. Louis, Missouri
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5
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Molitor M, Mestak O, Pink R, Foltan R, Sukop A, Lucchina S. The use of sentinel skin islands for monitoring buried and semi-buried micro-vascular flaps. Part I: Summary and brief description of monitoring methods. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2021; 165:113-130. [PMID: 33821844 DOI: 10.5507/bp.2021.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 02/26/2021] [Indexed: 11/23/2022] Open
Abstract
Micro-vascular flaps have been used for the repair of challenging defects for over 45 years. The risk of failure is reported to be around 5-10% which despite medical and technical advances in recent years remains essentially unchanged. Precise, continuous, sensitive and specific monitoring together with prompt notification of vascular compromise is crucial for the success of the procedure. In this review, we provide a classification and brief description of the reported methods for monitoring the micro-vascular flap and a summary of the benefits over direct visual monitoring. Over 40 different monitoring techniques have been reported but their comparative merits are not always obvious. One looks for early detection of a flap's compromise, improved flap salvage rate and a minimal false-positive or false-negative rate. The cost-effectiveness of any method should also be considered. Direct visualisation of the flap is the method most generally used and still seems to be the simplest, cheapest and most reliable method for flap monitoring. Considering the alternatives, only implantable Doppler ultrasound probes, near infrared spectroscopy and laser Doppler flowmetry have shown any evidence of improved flap salvage rates over direct visual monitoring.
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Affiliation(s)
- Martin Molitor
- Department of Plastic Surgery, First Faculty of Medicine Charles University and Na Bulovce Hospital, Prague, Czech Republic
| | - Ondrej Mestak
- Department of Plastic Surgery, First Faculty of Medicine Charles University and Na Bulovce Hospital, Prague, Czech Republic
| | - Richard Pink
- Department of Maxillofacial Surgery, University Hospital Olomouc and Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic
| | - Rene Foltan
- Department of Maxillofacial Surgery, General University Hospital and 1st Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Andrej Sukop
- Department of Plastic Surgery, University Hospital Kralovske Vinohrady and 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Stefano Lucchina
- Hand Unit, General Surgery Department, Locarno's Regional Hospital, Via Ospedale 1, 6600 Locarno, Switzerland
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6
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Vennemann B, Obrist D, Rösgen T. A smartphone-enabled wireless and batteryless implantable blood flow sensor for remote monitoring of prosthetic heart valve function. PLoS One 2020; 15:e0227372. [PMID: 31935231 PMCID: PMC6959614 DOI: 10.1371/journal.pone.0227372] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022] Open
Abstract
Aortic valve disease is one of the leading forms of complications in the cardiovascular system. The failing native aortic valve is routinely surgically replaced with a bioprosthesis. However, insufficient durability of bioprosthetic heart valves often requires reintervention. Valve degradation can be assessed by an analysis of the blood flow characteristics downstream of the valve. This is cost and labor intensive using clinical methodologies and is performed infrequently. The integration of consumer smartphones and implantable blood flow sensors into the data acquisition chain facilitates remote management of patients that is not limited by access to clinical facilities. This article describes the characteristics of an implantable magnetic blood flow sensor which was optimized for small size and low power consumption to allow for batteryless operation. The data is wirelessly transmitted to the patient's smartphone for in-depth processing. Tests using three different experimental setups confirmed that wireless and batteryless blood flow recording using a magnetic flow meter technique is feasible and that the sensor system is capable of monitoring the characteristic flow downstream of the valve.
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Affiliation(s)
- Bernhard Vennemann
- Institute of Fluid Dynamics, ETH Zürich, Zürich, Switzerland
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Thomas Rösgen
- Institute of Fluid Dynamics, ETH Zürich, Zürich, Switzerland
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7
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Hoare D, Bussooa A, Neale S, Mirzai N, Mercer J. The Future of Cardiovascular Stents: Bioresorbable and Integrated Biosensor Technology. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900856. [PMID: 31637160 PMCID: PMC6794628 DOI: 10.1002/advs.201900856] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/26/2019] [Indexed: 05/15/2023]
Abstract
Cardiovascular disease is the greatest cause of death worldwide. Atherosclerosis is the underlying pathology responsible for two thirds of these deaths. It is the age-dependent process of "furring of the arteries." In many scenarios the disease is caused by poor diet, high blood pressure, and genetic risk factors, and is exacerbated by obesity, diabetes, and sedentary lifestyle. Current pharmacological anti-atherosclerotic modalities still fail to control the disease and improvements in clinical interventions are urgently required. Blocked atherosclerotic arteries are routinely treated in hospitals with an expandable metal stent. However, stented vessels are often silently re-blocked by developing "in-stent restenosis," a wound response, in which the vessel's lumen renarrows by excess proliferation of vascular smooth muscle cells, termed hyperplasia. Herein, the current stent technology and the future of biosensing devices to overcome in-stent restenosis are reviewed. Second, with advances in nanofabrication, new sensing methods and how researchers are investigating ways to integrate biosensors within stents are highlighted. The future of implantable medical devices in the context of the emerging "Internet of Things" and how this will significantly influence future biosensor technology for future generations are also discussed.
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Affiliation(s)
- Daniel Hoare
- BHF Cardiovascular Research CentreUniversity of GlasgowG12 8TAGlasgowScotland
| | - Anubhav Bussooa
- BHF Cardiovascular Research CentreUniversity of GlasgowG12 8TAGlasgowScotland
| | - Steven Neale
- James Watt South BuildingSchool of EngineeringUniversity of GlasgowG12 8QQGlasgowScotland
| | - Nosrat Mirzai
- Bioelectronics UnitCollege of Medical, Veterinary & Life Sciences (MVLS)University of GlasgowG12 8QQGlasgowScotland
| | - John Mercer
- BHF Cardiovascular Research CentreUniversity of GlasgowG12 8TAGlasgowScotland
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8
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Schlemm L. Disability Adjusted Life Years due to Ischaemic Stroke Preventable by Real-Time Stroke Detection-A Cost-Utility Analysis of Hypothetical Stroke Detection Devices. Front Neurol 2018; 9:814. [PMID: 30327638 PMCID: PMC6174318 DOI: 10.3389/fneur.2018.00814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 09/10/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Ischaemic stroke remains a significant contributor to permanent disability world-wide. Therapeutic interventions for acute ischaemic stroke (AIS) are available, but need to be administered early after symptom onset in order to be effective. Currently, one of the main factors responsible for poor clinical outcome is an unnecessary long time between symptom onset and arrival at a hospital (pre-hospital delay). In the future, technological devices with the capability of real-time detection of AIS may become available. The health economic implications of such devices have not been explored. Methods: We developed a novel probabilistic model to estimate the maximally allowable annual costs of different hypothetical real-time AIS detection devices in different populations given currently accepted willingness-to-pay thresholds. Distributions of model parameters were extracted from the literature. Effectiveness of the intervention was quantified as reduction in disability-adjusted life-years associated with faster access to thrombolysis and mechanical thrombectomy. Incremental costs were calculated from a societal perspective including acute treatment costs and long-term costs for nursing care, home help, and loss of production. The impact of individual model parameters was explored in one-way and multi-way sensitivity analyses. Results: The model yields significantly shorter prehospital delays and a higher proportion of acute ischaemic patients that fulfill the time-based eligibility criteria for thrombolysis or mechanical thrombectomy in the scenario with a real-time stroke detection device as compared to the control scenario. Depending on the sociodemographic and geographic characteristics of the study population and operating characteristics of the device, the maximally allowable annual cost for the device to operate in a cost-effective manner assuming a willingness-to-pay threshold of GBP 30.000 ranges from GBP 22.00 to GBP 9,952.00. Considering the results of multiway sensitivity analyses, the upper bound increases to GBP 29,449.10 in the subgroup of young patients with a very high annual risk of ischaemic stroke (50 years/20% annual risk). Conclusion: Data from probabilistic modeling suggest that real-time AIS detection devices can be expected to be cost-effective only for a small group of highly selected individuals.
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Affiliation(s)
- Ludwig Schlemm
- Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Stroke Research Berlin, Charité-Universitätsmedizin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,Department of Health Policy, London School of Economics and Political Science, London, United Kingdom
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9
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Howe C, Mishra S, Kim YS, Chen Y, Ye SH, Wagner WR, Jeong JW, Byun HS, Kim JH, Chun Y, Yeo WH. Stretchable, Implantable, Nanostructured Flow-Diverter System for Quantification of Intra-aneurysmal Hemodynamics. ACS NANO 2018; 12:8706-8716. [PMID: 30021063 DOI: 10.1021/acsnano.8b04689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Random weakening of an intracranial blood vessel results in abnormal blood flow into an aneurysmal sac. Recent advancements show that an implantable flow diverter, integrated with a medical stent, enables a highly effective treatment of cerebral aneurysms by guiding blood flow into the normal vessel path. None of such treatment systems, however, offers post-treatment monitoring to assess the progress of sac occlusion. Therefore, physicians rely heavily on either angiography or magnetic resonance imaging. Both methods require a dedicated facility with sophisticated equipment settings and time-consuming, cumbersome procedures. In this paper, we introduce an implantable, stretchable, nanostructured flow-sensor system for quantification of intra-aneurysmal hemodynamics. The open-mesh membrane device is capable of effective implantation in complex neurovascular vessels with extreme stretchability (500% radial stretching) and bendability (180° with 0.75 mm radius of curvature) for monitoring of the treatment progress. A collection of quantitative mechanics, fluid dynamics, and experimental studies establish the fundamental aspects of design criteria for a highly compliant, implantable device. Hemocompatibility study using fresh ovine blood captures the device feasibility for long-term insertion in a blood vessel, showing less platelet deposition compared to that in existing implantable materials. In vitro demonstrations of three types of flow sensors show quantification of intra-aneurysmal blood flow in a pig aorta and the capability of observation of aneurysm treatment with a great sensitivity (detection limit as small as 0.032 m/s). Overall, this work describes a mechanically soft flow-diverter system that offers an effective treatment of aneurysms with an active monitoring of intra-aneurysmal hemodynamics.
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Affiliation(s)
- Connor Howe
- Department of Mechanical and Nuclear Engineering, Institute for Engineering and Medicine, Center for Rehabilitation Science and Engineering , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
| | - Saswat Mishra
- George W. Woodruff School of Mechanical Engineering, College of Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Yun-Soung Kim
- George W. Woodruff School of Mechanical Engineering, College of Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Yanfei Chen
- Department of Industrial Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Sang-Ho Ye
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - William R Wagner
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Jae-Woong Jeong
- School of Electrical Engineering , Korea Advanced Institute of Science and Technology , Daejeon , Republic of Korea 34141
| | - Hun-Soo Byun
- Department of Chemical and Biomolecular Engineering , Chonnam National University , Yeosu , Jeonnam 59626 , South Korea
| | - Jong-Hoon Kim
- School of Engineering and Computer Science , Washington State University , Vancouver , Washington 98686 , United States
| | - Youngjae Chun
- Department of Industrial Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
- Department of Bioengineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Woon-Hong Yeo
- Department of Mechanical and Nuclear Engineering, Institute for Engineering and Medicine, Center for Rehabilitation Science and Engineering , Virginia Commonwealth University , Richmond , Virginia 23284 , United States
- George W. Woodruff School of Mechanical Engineering, College of Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
- Institute for Electronics and Nanotechnology, Bioengineering Interdisciplinary Program, Petit Institute for Bioengineering & Bioscience, and Center for Flexible Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
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10
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Rothfuss MA, Unadkat JV, Gimbel ML, Mickle MH, Sejdić E. Totally Implantable Wireless Ultrasonic Doppler Blood Flowmeters: Toward Accurate Miniaturized Chronic Monitors. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:561-578. [PMID: 28038789 DOI: 10.1016/j.ultrasmedbio.2016.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 10/27/2016] [Accepted: 11/12/2016] [Indexed: 06/06/2023]
Abstract
Totally implantable wireless ultrasonic blood flowmeters provide direct-access chronic vessel monitoring in hard-to-reach places without using wired bedside monitors or imaging equipment. Although wireless implantable Doppler devices are accurate for most applications, device size and implant lifetime remain vastly underdeveloped. We review past and current approaches to miniaturization and implant lifetime extension for wireless implantable Doppler devices and propose approaches to reduce device size and maximize implant lifetime for the next generation of devices. Additionally, we review current and past approaches to accurate blood flow measurements. This review points toward relying on increased levels of monolithic customization and integration to reduce size. Meanwhile, recommendations to maximize implant lifetime should include alternative sources of power, such as transcutaneous wireless power, that stand to extend lifetime indefinitely. Coupling together the results will pave the way for ultra-miniaturized totally implantable wireless blood flow monitors for truly chronic implantation.
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Affiliation(s)
- Michael A Rothfuss
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jignesh V Unadkat
- Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael L Gimbel
- Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Marlin H Mickle
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ervin Sejdić
- Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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11
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Implantable Doppler Probes for Postoperatively Monitoring Free Flaps: Efficacy. A Systematic Review and Meta-analysis. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2016; 4:e1099. [PMID: 27975015 PMCID: PMC5142481 DOI: 10.1097/gox.0000000000001099] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 09/02/2016] [Indexed: 11/25/2022]
Abstract
Background: Although clinical assessment remains the gold standard for monitoring the circulation of free flaps, several adjunct techniques promote timely salvage by detecting circulation compromise early. The objective of this systematic review was to evaluate the efficacy of an implantable Doppler probe for postoperatively monitoring free flaps. Materials and Methods: English-language articles evaluating the efficacy of implantable Doppler probes compared with clinical assessment for postoperatively monitoring free flaps were analyzed. The outcome measures were total flap failure rates, salvage rates, sensitivity, false-positive rates, and positive likelihood ratios. Results: Of the 504 citations identified, 6 comparative studies were included for meta-analysis. An implantable Doppler probe significantly lowered the flap failure rate (risk ratio: 0.40; 95% confidence interval: 0.21–0.75) and raised the successful salvage rate (risk ratio: 1.73; 95% confidence interval: 1.16–2.59). Pooled sensitivity was higher (1.00 vs 0.98), the positive likelihood ratio was lower (72.16 vs 220.48), and the false-positive rate was higher (0.01 vs 0) in the implantable Doppler probe group than in the clinical assessment group. Conclusion: An implantable Doppler probe is significantly more efficacious than clinical assessment for postoperatively monitoring free flaps.
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