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Mondal A, Visner GA, Kaza AK, Dupont PE. A novel ex vivo tracheobronchomalacia model for airway stent testing and in vivo model refinement. J Thorac Cardiovasc Surg 2023; 166:679-687.e1. [PMID: 37156367 PMCID: PMC10524727 DOI: 10.1016/j.jtcvs.2023.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/14/2023] [Accepted: 04/10/2023] [Indexed: 05/10/2023]
Abstract
OBJECTIVES We sought to develop an ex vivo trachea model capable of producing mild, moderate, and severe tracheobronchomalacia for optimizing airway stent design. We also aimed to determine the amount of cartilage resection required for achieving different tracheobronchomalacia grades that can be used in animal models. METHODS We developed an ex vivo trachea test system that enabled video-based measurement of internal cross-sectional area as intratracheal pressure was cyclically varied for peak negative pressures of 20 to 80 cm H2O. Fresh ovine tracheas were induced with tracheobronchomalacia by single mid-anterior incision (n = 4), mid-anterior circumferential cartilage resection of 25% (n = 4), and 50% per cartilage ring (n = 4) along an approximately 3-cm length. Intact tracheas (n = 4) were used as control. All experimental tracheas were mounted and experimentally evaluated. In addition, helical stents of 2 different pitches (6 mm and 12 mm) and wire diameters (0.52 mm and 0.6 mm) were tested in tracheas with 25% (n = 3) and 50% (n = 3) circumferentially resected cartilage rings. The percentage collapse in tracheal cross-sectional area was calculated from the recorded video contours for each experiment. RESULTS Ex vivo tracheas compromised by single incision and 25% and 50% circumferential cartilage resection produce tracheal collapse corresponding to clinical grades of mild, moderate, and severe tracheobronchomalacia, respectively. A single anterior cartilage incision produces saber-sheath type tracheobronchomalacia, whereas 25% and 50% circumferential cartilage resection produce circumferential tracheobronchomalacia. Stent testing enabled the selection of stent design parameters such that airway collapse associated with moderate and severe tracheobronchomalacia could be reduced to conform to, but not exceed, that of intact tracheas (12-mm pitch, 0.6-mm wire diameter). CONCLUSIONS The ex vivo trachea model is a robust platform that enables systematic study and treatment of different grades and morphologies of airway collapse and tracheobronchomalacia. It is a novel tool for optimization of stent design before advancing to in vivo animal models.
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Affiliation(s)
- Abhijit Mondal
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass; Department of Surgery, Harvard Medical School, Boston, Mass.
| | - Gary A Visner
- Division of Pulmonary Medicine, Boston Children's Hospital, Boston, Mass; Department of Pediatrics, Harvard Medical School, Boston, Mass
| | - Aditya K Kaza
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass; Department of Surgery, Harvard Medical School, Boston, Mass
| | - Pierre E Dupont
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass; Department of Surgery, Harvard Medical School, Boston, Mass
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A New Removable Helical Metallic Stent for the Treatment of Tracheomalacia in Children: Study in Pathological Animal Model. J Clin Med 2022; 11:jcm11226757. [PMID: 36431234 PMCID: PMC9695607 DOI: 10.3390/jcm11226757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Congenital tracheomalacia is a pathology with no consensus of medical or surgical approach. The permanent nature and the major complications associated with metallic stents have limited their use over the years. The purpose of this study was to evaluate the feasibility of a helical stent design removal. METHODS Ten dogs diagnosed with tracheal collapse and treated with the helical stent were involved in the study. Animals were classified into three groups depending on stent indwelling time. Prior to the removal, endoscopic evaluation was performed to assess endothelization grade, mucous accumulation, and the presence of stenosis. During the removal, bleeding, fracture, or impossibility of removal were noted. After the removal, all macroscopic mucosal changes were recorded. RESULTS Technical success was 100%, without any complications. Complete epithelization of the stent was visualized in 7/10 animals. The removal procedure duration ranged from 2-12 min. At post-removal endoscopy, bleeding or epithelial damage, was visualized in any case. Stent fracture during removal occurred in one animal. CONCLUSIONS The removal of a metallic stent with spiral geometry is feasible, simple, and without complications, regardless of the degree of neo-epithelialization.
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Mencattelli M, Mondal A, Miale R, Van Story D, Peine J, Li Y, Artoni A, Kaza AK, Dupont PE. In Vivo Molding of Airway Stents. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2010525. [PMID: 34335133 PMCID: PMC8323946 DOI: 10.1002/adfm.202010525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Indexed: 06/13/2023]
Abstract
Like ready-to-wear clothing, medical devices come in a fixed set of sizes. While this may accommodate a large fraction of the patient population, others must either experience suboptimal results due to poor sizing or must do without the device. Although techniques have been proposed to fabricate patient-specific devices in advance of a procedure, this process is expensive and time consuming. An alternative solution that provides every patient with a tailored fit is to create devices that can be customized to the patient's anatomy as they are delivered. This paper reports an in vivo molding process in which a soft flexible photocurable stent is delivered into the trachea or bronchi over a UV-transparent balloon. The balloon is expanded such that the stent conforms to the varying cross-sectional shape of the airways. UV light is then delivered through the balloon curing the stent into its expanded conformal shape. The potential of this method is demonstrated using phantom, ex vivo and in vivo experiments. This approach can produce stents providing equivalent airway support to those made from standard materials while providing a customized fit.
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Affiliation(s)
- Margherita Mencattelli
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115 USA
| | - Abhijit Mondal
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115 USA
| | - Roberta Miale
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115 USA
| | - David Van Story
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115 USA; currently at Therapeutic Technology Design and Development Lab, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139 USA
| | - Joseph Peine
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115 USA
| | - Yingtian Li
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115 USA; currently at Institute of Biomedical & Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
| | - Alessio Artoni
- Dipartimento di Ingegneria Civile e Industriale, Universita di Pisa, Largo Lucio Lazzarino 2, 56122 Pisa, Italy
| | - Aditya K Kaza
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA 02115 USA
| | - Pierre E Dupont
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA 02115 USA
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Mondal A, Kaza AK, Dupont PE. Response to comments on preclinical evaluation of a pediatric airway stent for tracheobronchomalacia. J Thorac Cardiovasc Surg 2020; 163:e109. [DOI: 10.1016/j.jtcvs.2020.07.099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/09/2020] [Accepted: 07/15/2020] [Indexed: 11/26/2022]
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Overbey DM, Turek JW, Andersen ND. Commentary: Malacia got you down? Unwind with a helical stent. J Thorac Cardiovasc Surg 2020; 161:S0022-5223(20)31020-5. [PMID: 32451075 DOI: 10.1016/j.jtcvs.2020.04.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 04/21/2020] [Indexed: 01/14/2023]
Affiliation(s)
- Douglas M Overbey
- Duke Children's Pediatric & Congenital Heart Center, Duke Children's Hospital, Durham, NC
| | - Joseph W Turek
- Duke Children's Pediatric & Congenital Heart Center, Duke Children's Hospital, Durham, NC
| | - Nicholas D Andersen
- Duke Children's Pediatric & Congenital Heart Center, Duke Children's Hospital, Durham, NC.
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Bryant R. Commentary: Toward a more ideal pediatric airway stent for tracheobronchomalacia. J Thorac Cardiovasc Surg 2020; 161:S0022-5223(20)30974-0. [PMID: 32414600 DOI: 10.1016/j.jtcvs.2020.04.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/03/2020] [Accepted: 04/03/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Roosevelt Bryant
- Division of Congenital Heart Surgery, The Heart Center, Phoenix Children's Hospital, Phoenix, Ariz.
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