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Goshtasbi K, Nguyen TV, Prasad KR, Hong EM, Sterritt N, Dilley KK, Kozlowski K, Ha A, Wong BJF. Impact of Tissue Handling and Size Modification on Septal Chondrocyte Viability. Laryngoscope 2024; 134:4259-4265. [PMID: 38924582 DOI: 10.1002/lary.31546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/11/2024] [Accepted: 05/13/2024] [Indexed: 06/28/2024]
Abstract
INTRODUCTION The physical modification of cartilage grafts during rhinoplasty risks chondrocyte death at the margins where the tissue is cut. This study compares chondrocyte viability between diced, scaled, and pate samples in human models, and further computes percent chondrocyte viability as a function of sequential dicing size in a computational model. METHODS Septal cartilage from 11 individuals was prepared as follows: diced (1 mm cubic), scaled (shaved to <1 mm thickness ~ translucent), pate (0.02 g of scraped cartilage surface), positive control (2 × 2 mm diced), and negative control (2 × 2 mm diced soaked in 70% EtOH). Viability analysis was performed using Live/Dead assay™ and confocal microscopy. Numerical simulation of cartilage dicing in 0.05 mm increments was performed using MATLAB assuming 250 chondrocytes/mm3 with each average chondrocyte size of 65 μm2. RESULTS Chondrocyte viability was similar between 1 mm diced cartilage, scaled cartilage, and positive control samples (p > 0.05). Conversely, pate samples had significantly less viability compared to positive controls, diced samples, and scaled samples (all p < 0.01 after Bonferroni correction). Pate samples had similar chondrocyte viability compared to negative controls (p = 0.36). On computational modeling, cartilage viability decreased to 50% as the diced sample was cut from 1 mm edge length to 0.7-0.8 mm. Similarly, cartilage viability decreased to 26% at 0.55-0.65 mm, 11% at 0.4-0.5 mm, and <5% at <0.4 mm edge length. CONCLUSION Modifying septal cartilage grafts into 1 mm diced or scaled samples maintains ideal chondrocyte viability whereas pate preparations result in significant chondrocyte death. According to computational analysis, chondrocyte viability sharply decreases as the cartilage is diced below 0.7-0.8 mm. LEVEL OF EVIDENCE N/A Laryngoscope, 134:4259-4265, 2024.
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Affiliation(s)
- Khodayar Goshtasbi
- Department of Otolaryngology-Head and Neck Surgery, University of California Irvine, Irvine, California, U.S.A
| | - Theodore V Nguyen
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
| | - Karthik R Prasad
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
| | - Ellen M Hong
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
| | - Naya Sterritt
- School of Biomedical Engineering, University of California Irvine, Irvine, California, U.S.A
| | - Katelyn K Dilley
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
| | - Konrad Kozlowski
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
| | - Alexis Ha
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
| | - Brian J F Wong
- Department of Otolaryngology-Head and Neck Surgery, University of California Irvine, Irvine, California, U.S.A
- Beckman Laser Institute, University of California Irvine, Irvine, California, U.S.A
- School of Biomedical Engineering, University of California Irvine, Irvine, California, U.S.A
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Abello EH, Nguyen TV, Dilley KK, Hong D, Kim JS, Nair PS, Bitner BF, Jia W, Wong BJF. Temperature Profile Measurement From Radiofrequency Nasal Airway Reshaping Device. Laryngoscope 2024; 134:1063-1070. [PMID: 37594207 DOI: 10.1002/lary.30942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/17/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023]
Abstract
OBJECTIVE Nasal airway obstruction (NAO) is caused by various disorders including nasal valve collapse (NVC). A bipolar radiofrequency (RF) device (VivAer®, Aerin Medical, Sunnyvale, CA) has been used to treat NAO through RF heat generation to the upper lateral cartilage (ULC). The purpose of this study is to measure temperature elevations in nasal tissue, using infrared (IR) radiometry to map the spatial and temporal evolution of temperature. STUDY DESIGN Experimental and computational. METHODS Composite porcine nasal septum was harvested and sectioned (1 mm and 2 mm). The device was used to heat the cartilage in composite porcine septum. An IR camera (FLIR® ExaminIR, Teledyne, Wilsonville, OR) was used to image temperature on the back surface of the specimen. These data were incorporated into a heat transfer finite element model that also calculated tissue damage using Arrhenius rate process. RESULTS IR temperature imaging showed peak back surface temperatures of 49.57°C and 42.21°C in 1 and 2 mm thick septums respectively. Temperature maps were generated demonstrating the temporal and spatial evolution of temperature. A finite element model generated temperature profiles with respect to time and depth. Rate process models using Arrhenius coefficients showed 30% chondrocyte death at 1 mm depth after 18 s of RF treatment. CONCLUSION The use of this device creates a thermal profile that may result in thermal injury to cartilage. Computational modeling suggests chondrocyte death extending as deep as 1.4 mm below the treatment surface. Further studies should be performed to improve dosimetry and optimize the heating process to reduce potential injury. Laryngoscope, 134:1063-1070, 2024.
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Affiliation(s)
- Eric H Abello
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
- Department of Otolaryngology - Head and Neck Surgery, University of California - Irvine Medical Center, Orange, California, USA
| | | | - Katelyn K Dilley
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
| | - Donggyoon Hong
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
| | - Justin S Kim
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
| | - Pranav S Nair
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
| | - Benjamin F Bitner
- Department of Otolaryngology - Head and Neck Surgery, University of California - Irvine Medical Center, Orange, California, USA
| | - Wangcun Jia
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
| | - Brian J F Wong
- Beckman Laser Institute and Medical Clinic, Irvine, California, USA
- Department of Otolaryngology - Head and Neck Surgery, University of California - Irvine Medical Center, Orange, California, USA
- Department of Biomedical Engineering, Henry Samueli School of Engineering, Irvine, California, USA
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Pham TT, Stokolosa AM, Borden PA, Hansen KD, Hong EM, Krasieva TB, Sivoraphonh RH, Moy WJ, Heidari AE, Lee LH, Kim EH, Sun CH, Jia W, Mo JH, Kim S, Hill MG, Wong BJF. Electrochemical degradation and saponification of porcine adipose tissue. Sci Rep 2020; 10:20745. [PMID: 33247200 PMCID: PMC7695738 DOI: 10.1038/s41598-020-76678-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/19/2020] [Indexed: 02/01/2023] Open
Abstract
Body contouring achieved via subcutaneous adipose tissue reduction has notably advanced over the past century, from suction assisted lipectomy to techniques with reduced degrees of invasiveness including laser, radiofrequency, high frequency focused ultrasound, cryolipolysis, and drug-based injection approaches. These costly techniques have focused on damaging adipocyte cell membranes, hydrolyzing triglycerides (TGs), or inducing apoptosis. Here, we present a simple, low-cost technique, termed electrochemical lipolysis (ECLL). During ECLL, saline is injected into the subcutaneous adipose tissue, followed by insertion of needle electrodes and application of an electrical potential. Electrolysis of saline creates localized pH gradients that drive adipocyte death and saponification of TGs. Using pH mapping, various optical imaging techniques, and biochemical assays, we demonstrate the ability of ECLL to induce acid and base injury, cell death, and the saponification of triglycerides in ex vivo porcine adipose tissue. We define ECLL's potential role as a minimally-invasive, ultra-low-cost technology for reducing and contouring adipose tissue, and present ECLL as a potential new application of an emerging electrochemical redox based treatment modality.
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Affiliation(s)
- Tiffany T Pham
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Anna M Stokolosa
- Department of Chemistry, Occidental College, Los Angeles, CA, 90041, USA
| | - Pamela A Borden
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
- Department of Biomedical Engineering, Beckman Laser Institute, University of California - Irvine, 1002 Health Sciences Road, Irvine, CA, 92697, USA
| | - Kyle D Hansen
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
- Department of Biomedical Engineering, Beckman Laser Institute, University of California - Irvine, 1002 Health Sciences Road, Irvine, CA, 92697, USA
| | - Ellen M Hong
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Tatiana B Krasieva
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Ryan H Sivoraphonh
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Wesley J Moy
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
- Department of Biomedical Engineering, Beckman Laser Institute, University of California - Irvine, 1002 Health Sciences Road, Irvine, CA, 92697, USA
| | - Andrew E Heidari
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
- Department of Biomedical Engineering, Beckman Laser Institute, University of California - Irvine, 1002 Health Sciences Road, Irvine, CA, 92697, USA
| | - Lauren H Lee
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Eun-Hee Kim
- Beckman Laser Institute-Korea, Dankook University College of Medicine, Cheonan-si, Chungnam, 31116, Republic of Korea
| | - Chung- Ho Sun
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Wangcun Jia
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA
| | - Ji -Hun Mo
- Department of Otorhinolaryngology, Dankook University College of Medicine, Cheonan-siChungnam, 31116, Republic of Korea
| | - Sehwan Kim
- Department of Biomedical Engineering, Dankook University College of Medicine, Cheonan-siChungnam, 31116, Republic of Korea
| | - Michael G Hill
- Department of Chemistry, Occidental College, Los Angeles, CA, 90041, USA
| | - Brian J F Wong
- Beckman Laser Institute and Medical Clinic, University of California - Irvine, Irvine, CA, 92612, USA.
- Department of Biomedical Engineering, Beckman Laser Institute, University of California - Irvine, 1002 Health Sciences Road, Irvine, CA, 92697, USA.
- Department of Otolaryngology - Head and Neck Surgery, School of Medicine, University of California - Irvine, Orange, CA, 92868, USA.
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Yafit D, Basov S, Katzir A, Fliss D, DeRowe A. Laser Soldering of Cartilage Graft Interposed Into a Tracheal Incision in a Porcine Model. Laryngoscope 2018; 129:58-62. [PMID: 30208211 DOI: 10.1002/lary.27468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVES/HYPOTHESIS Investigate the feasibility of soldering a free cartilage graft into a tracheal defect by laser heating and assessing the resulting burst pressure and thermal damage to the cartilage. STUDY DESIGN Animal study. METHODS A 20 × 8 mm defect was created in fresh cadaveric pig tracheas, a cartilage graft of the same size was harvested from the thyroid ala cartilage, and the graft was fitted into the defect. The soldering process involved covering the edges with liquid albumin and using a fiber-laser system for heating the edges to temperature T under temperature control. This was done for groups of grafts at various temperatures T = 60°C to 90°C. The tracheas were sealed, for each group the burst pressure was measured, and a histologic examination of the soldered incisions was performed. RESULTS The burst pressures were in the range of 66 to 409 mm Hg. The median burst pressure was 78, 157, 231, and 146 mm Hg, respectively, for T = 60°C, 70°C, 80°C, and 90°C. Statistical analysis revealed significant differences in burst pressures between the T = 60°C group and the T = 80°C and T = 90°C groups (P < .05). The highest burst pressure was measured in the T = 80°C group. Histologic examination revealed no thermal damage to the cartilage at this temperature. CONCLUSIONS Performing a sutureless laser soldering of a free cartilage graft to a tracheal defect, achieving an immediate watertight bond, is feasible. At T = 80°C the highest burst pressures were achieved. No histologic damage was observed. In vivo studies are needed before implementation of this technique in laryngotracheopasty. LEVEL OF EVIDENCE NA Laryngoscope, 129:58-62, 2019.
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Affiliation(s)
- Daniel Yafit
- Department of Otolaryngology-Head and Neck and Maxillofacial Surgery, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Svetlana Basov
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Abraham Katzir
- School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
| | - Dan Fliss
- Department of Otolaryngology-Head and Neck and Maxillofacial Surgery, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ari DeRowe
- Department of Otolaryngology-Head and Neck and Maxillofacial Surgery, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Gandy JR, Lemieux B, Foulad A, Wong BJF. Modular Component Assembly Approach to Microtia Reconstruction. JAMA FACIAL PLAST SU 2016; 18:120-7. [PMID: 26720326 DOI: 10.1001/jamafacial.2015.1838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Current methods of microtia reconstruction include carving an auricular framework from the costal synchondrosis. This requires considerable skill and may create a substantial defect at the donor site. OBJECTIVE To present a modular component assembly (MCA) approach that minimizes the procedural difficulty with microtia repair and reduces the amount of cartilage to a single rib. DESIGN, SETTING, AND PARTICIPANTS Ex vivo study and survey. A single porcine rib was sectioned into multiple slices using a cartilage guillotine, cut into components outlined by 3-dimensional printed templates, and assembled into an auricular scaffold. Electromechanical reshaping was used to bend cartilage slices for creation of the helical rim. Chondrocyte viability was confirmed using confocal imaging. Ten surgeons reviewed the scaffold constructed with the MCA approach to evaluate aesthetics, stability, and clinical feasibility. The study was conducted from June 5 to December 18, 2014. MAIN OUTCOMES AND MEASURES The primary outcome was creation of a modular component assembly method that decreases the total amount of rib needed for scaffold construction, as well as overall scaffold acceptability. The surgeons provided their assessments through a Likert-scale survey, with responses ranging from 1 (disagree with the statement) to 5 (agree with the statement). Thus, a higher score represents that the surgeon agrees that the scaffold is structurally and aesthetically acceptable and feasible. RESULTS An auricular framework with projection and curvature was fashioned from 1 rib. The 10 surgeons who participated in the survey indicated that the MCA scaffold would meet minimal aesthetic and anatomic acceptability. When embedded under a covering, the region of the helix and antihelix of the scaffold scored significantly higher on the assessment survey than that of an embedded alloplast implant (mean [SD], 4.6 [0.97] vs 3.5 [1.27]; P = .007). Otherwise, no significant difference was found between the embedded MCA and alloplast implants (4.42 [0.48] vs 3.87 [0.41]; P = .13). Cartilage prepared with electromechanical reshaping was viable. CONCLUSIONS AND RELEVANCE This study demonstrates that 1 rib can be used to create an aesthetic and durable framework for microtia repair. Precise assembly and the ability to obtain thin, uniform slices of cartilage were essential. This cartilage-sparing MCA approach may be an alternative to classic techniques. LEVEL OF EVIDENCE NA.
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Affiliation(s)
- Jessica R Gandy
- Medical student, School of Medicine, University of California-Irvine, Irvine2Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine
| | - Bryan Lemieux
- Medical student, School of Medicine, University of California-Irvine, Irvine2Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine
| | - Allen Foulad
- Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine3Department of Otolaryngology, Head and Neck Surgery, University of California-Irvine, Orange
| | - Brian J F Wong
- Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine3Department of Otolaryngology, Head and Neck Surgery, University of California-Irvine, Orange4Department of Otolaryngology, Head and Neck Surgery, University of California-
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Yau AYY, Manuel C, Hussain SF, Protsenko DE, Wong BJF. In vivo needle-based electromechanical reshaping of pinnae: New Zealand White rabbit model. JAMA FACIAL PLAST SU 2015; 16:245-52. [PMID: 24854476 DOI: 10.1001/jamafacial.2014.85] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Electromechanical reshaping (EMR) is a low-cost, needle-based, and simple means to shape cartilage tissue without the use of scalpels, sutures, or heat that can potentially be used in an outpatient setting to perform otoplasty. OBJECTIVES To demonstrate that EMR can alter the shape of intact pinnae in an in vivo animal model and to show that the amount of shape change and the limited cell injury are proportional to the dosimetry. DESIGN, SETTING, AND SPECIMENS In an academic research setting, intact ears of 18 New Zealand white rabbits underwent EMR using 6 different dosimetry parameters (4 V for 5 minutes, 4 V for 4 minutes, 5 V for 3 minutes, 5 V for 4 minutes, 6 V for 2 minutes, and 6 V for 3 minutes). A custom acrylic jig with 2 rows of platinum needle electrodes was used to bend ears at the middle of the pinna and to perform EMR. Treatment was repeated twice per pinna, in proximal and distal locations. Control pinnae were not subjected to current application when being bent and perforated within the jig. Pinnae were splinted for 3 months along the region of the bend using soft silicon sheeting and a cotton bolster. MAIN OUTCOMES AND MEASURES The ears were harvested the day after splints were removed and before euthanasia. Photographs of ears were obtained, and bend angles were measured. Tissue was sectioned for histologic examination and confocal microscopy to assess changes to microscopic structure and cellular viability. RESULTS Treated pinnae were bent more and retained shape better than control pinnae. The mean (SD) bend angles in the 7 dosimetry groups were 55° (35°) for the control, 60° (15°) for 4 V for 4 minutes, 118° (15°) for 4 V for 5 minutes, 88° (26°) for 5 V for 3 minutes, 80° (17°) for 5 V for 4 minutes, 117° (21°) for 6 V for 2 minutes, and 125° (18°) for 6 V for 3 minutes. Shape change was proportional to electrical charge transfer, which increased with voltage and application time. Hematoxylin-eosin staining of the pinnae identified localized areas of cell injury and fibrosis in the cartilage and in the surrounding soft tissue where the needle electrodes were inserted. This circumferential zone of injury (range, 1.5-2.5 mm) corresponded to dead cells on cell viability assay, and the diameter of this region increased with total electrical charge transfer to a maximum of 2.5 mm at 6 V for 3 minutes. CONCLUSIONS AND RELEVANCE Electromechanical reshaping produced shape change in intact pinnae of rabbits in this expanded in vivo study. A short application of 4 to 6 V can achieve adequate reshaping of the pinnae. Tissue injury around the electrodes increases with the amount of total current transferred into the tissue and is modest in spatial distribution. This study is a critical step toward evaluation of EMR in clinical trials. LEVEL OF EVIDENCE NA.
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Affiliation(s)
- Amy Y Y Yau
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine
| | - Cyrus Manuel
- Beckman Laser Institute, University of California, Irvine
| | - Syed F Hussain
- Department of Biomedical Engineering, University of California, Irvine
| | | | - Brian J F Wong
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine2Beckman Laser Institute, University of California, Irvine3Department of Biomedical Engineering, University of California, Irvine
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Chlebicki CA, Protsenko DE, Wong BJ. Preliminary investigations on therapy thresholds for laser dosimetry, cryogen spray cooling duration, and treatment cycles for laser cartilage reshaping in the New Zealand white rabbit auricle. Lasers Med Sci 2014; 29:1099-109. [PMID: 24202858 PMCID: PMC4040347 DOI: 10.1007/s10103-013-1471-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 10/13/2013] [Indexed: 10/26/2022]
Abstract
Previous studies have demonstrated the feasibility of laser irradiation (λ = 1.45 μm) in tandem with cryogen spray cooling (CSC) to reshape rabbit auricular cartilage using a total energy density of 14 J/cm(2). The aim of this study was to further explore and identify the dosimetry parameter space for laser output energy, CSC duration, and treatment cycles required to achieve shape change while limiting skin and cartilage injury. Ten New Zealand white rabbits were treated with the 1.45 μm diode laser combined with cryogen spray cooling (Candela Smoothbeam™, Candela Co., Wayland, MA, USA). The ear's central portion was bent around a cylindrical jig and irradiated in consecutive spots of 6 mm diameter (13 or 14 J/cm(2) per spot) along three rows encompassing the bend. CSC was delivered during irradiation in cycles consisting of 25-35 ms. At thin and thick portions of the ear, 4-7 and 6-10 treatment cycles were delivered, respectively. After surgery, ears were examined and splinted for 6 weeks. Treatment parameters resulting in acceptable (grades 1 and 2) and unacceptable (grade 3) skin injuries for thick and thin regions were identified, and shape change was observed. Confocal and histological analysis of cartilage tissue revealed several outcomes correlating to laser dosimetry, CSC duration, and treatment cycles. These outcomes included expansion of cartilage layers (thickening), partial cartilage injuries, and full-thickness cartilage injuries. We determined therapy thresholds for laser output energy, cryogen spray cooling duration, and treatment cycles in the rabbit auricular model. These parameters are a starting point for future clinical procedures aimed at correcting external ear deformities.
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Affiliation(s)
- Cara A. Chlebicki
- Beckman Laser Institute and Medical Clinic, University of California Irvine, 1002 Health Sciences Road East, Irvine, California 92612
| | - Dmitry E. Protsenko
- Beckman Laser Institute and Medical Clinic, University of California Irvine, 1002 Health Sciences Road East, Irvine, California 92612
| | - Brian J. Wong
- Beckman Laser Institute and Medical Clinic, University of California Irvine, 1002 Health Sciences Road East, Irvine, California 92612
- Department of Otolaryngology, Head and Neck Surgery, University of California Irvine, 101 The City Drive, Orange, California 92668
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Oliaei S, Manuel C, Karam B, Hussain SF, Hamamoto A, Protsenko DE, Wong BJF. In vivo electromechanical reshaping of ear cartilage in a rabbit model: a minimally invasive approach for otoplasty. JAMA FACIAL PLAST SU 2013; 15:34-8. [PMID: 23117484 DOI: 10.1001/2013.jamafacial.2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To report the first successful study to date of in vivo electromechanical reshaping of ear cartilage in a rabbit model. METHODS Ears of New Zealand white rabbits were reshaped using percutaneous needle electrode electromechanical reshaping (5 V for 4 minutes) and were then bolstered for 4 weeks. Ten ears were treated, with 2 undergoing sham procedures and serving as controls. The treatment was performed using a platinum array of electrodes consisting of 4 parallel rows of needles inserted across the region of flexures in the ear. After 4 weeks, the animals were killed, and the ears were photographed and sectioned for conventional light microscopy and confocal microscopy (live-dead fluorescent assays). RESULTS Significant shape change was noted in all the treated ears (mean, 102.4°; range, 87°-122°). Control ears showed minimal shape retention (mean, 14.5°; range, 4°-25°). Epidermis and adnexal structures were preserved in reshaped ears, and neochondrogenesis was noted in all the specimens. Confocal microscopy demonstrated a localized zone of nonviable chondrocytes (<2.0 mm in diameter) surrounding needle sites in all the treated ears. CONCLUSIONS Electromechanical reshaping can alter the shape of the rabbit auricle, providing good creation and retention of shape, with limited skin and cartilage injury. Needle electrode electromechanical reshaping is a viable technique for minimally invasive tissue reshaping, with potential applications in otoplasty, septoplasty, and rhinoplasty. Further studies to refine dosimetry parameters will be required before clinical trials.
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Affiliation(s)
- Sepehr Oliaei
- Division of Facial Plastic Surgery, Department of Otolaryngology–Head and Neck Surgery, University of California-Irvine, 101 The City Drive S, Orange, CA 92868, USA
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Viability and Regeneration of Chondrocytes after Laser Cartilage Reshaping Using 1,460 nm Diode Laser. Clin Exp Otorhinolaryngol 2013; 6:82-9. [PMID: 23799165 PMCID: PMC3687067 DOI: 10.3342/ceo.2013.6.2.82] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/01/2013] [Accepted: 05/02/2013] [Indexed: 11/08/2022] Open
Abstract
Objectives Cartilage reshaping by laser irradiation is used to correct septal and auricular cartilage deformities. Chondrocyte viability following laser irradiation and reshaping has been well established. However, the regeneration process of chondrocyte after laser irradiation has not been revealed yet. The aims of this study were to determine the mechanism of cartilaginous thermal injury and the regenerative process of damaged cartilage following laser irradiation. Methods Laser irradiation was performed on human septal cartilage and rabbit auricular cartilage using a 1,460-nm diode laser. We observed change in the shape of cartilage and evaluated the extent of cartilage injury using live/dead cell assay via confocal microscopy. Hoechst and propidium iodide (PI) staining was used to evaluate the mechanism of chondrocyte injury after laser irradiation. To evaluate the regeneration of cartilage, laser irradiated cartilages were reimplanted into a subperichondrial pocket and were harvested at 1, 2, and 4 weeks after reimplantation for viability assessment and histologic examination. Results Laser irradiation using a 1,460-nm diode laser produced a marked shape change in both human septal and rabbit auricular cartilages. Thermal damage on cartilage was correlated with the exposure time and the laser power. Hoechst and PI staining showed that chondrocyte death by laser irradiation was due to mainly necrosis, rather than apoptosis. In lower power treatment group (0.3 W and 0.5 W), all the chondrocytes regenerated within 4 weeks, however, in 1 W treatment group, chondrocytes could not regenerate until 4 weeks. Conclusion Reshaping of cartilage using 1,460 nm diode laser was attained concurrently with the thermal injury to the chondrocytes. The extent of thermal damage on chondrocytes was dependent on the exposure time and the laser power and the damaged chondrocytes irradiated with lower level of laser power could be regenerated after reimplantation into subperichondrial pocket.
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Badran K, Manuel C, Waki C, Protsenko D, Wong BJF. Ex vivo electromechanical reshaping of costal cartilage in the New Zealand white rabbit model. Laryngoscope 2013; 123:1143-8. [PMID: 23553270 DOI: 10.1002/lary.23730] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 08/15/2012] [Accepted: 08/20/2012] [Indexed: 11/05/2022]
Abstract
OBJECTIVES/HYPOTHESIS Determine the effective electromechanical reshaping (EMR) parameters for shape change and cell viability in the ex vivo rabbit costal cartilage model. STUDY DESIGN Ex vivo animal study combined with computer modeling to guide electrode placement and polarity selection. METHODS Rabbit costal cartilages were secured in a jig that approximated the shape of the rabbit auricle framework. Finite element modeling was used to select the initial electrode geometry, polarity, spacing, and estimate dosimetry parameters. Porcine costal cartilage was utilized to refine the selection of dosing parameters. Parametric analysis was performed to determine the effect of voltage and application time on tissue shape change. Next, rabbit rib cartilage was reshaped, varying voltage and application time to identify the lowest parameters to produce acceptable shape change mimicking native auricular cartilage. Acceptable qualitative shape change was determined on a five-point Likert scale analyzed using one-way general linear analysis of variance. Confocal microscopy with live/dead cell viability analysis determined the degree of injury and the distribution of live and dead cells. RESULTS The minimum acceptable deformation of rabbit costal cartilage was found at 4 V-3 minutes. Viability analysis of cartilage reshaped at 4 V-3 minutes demonstrates cell injury extending 2 mm away from each electrode with viable cells found between the electrodes. CONCLUSIONS The EMR parameters of 4 V-3 minutes demonstrates appropriate shape change producing grafts that resemble the native auricle and contains the viable cells adequate for clinical evaluation. The rabbit auricular reconstruction model using EMR is a feasible one.
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Affiliation(s)
- Karam Badran
- School of Medicine, University of California-Irvine, Irvine, California, USA
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Foulad A, Ghasri P, Garg R, Wong B. Stabilization of costal cartilage graft warping using infrared laser irradiation in a porcine model. ACTA ACUST UNITED AC 2011; 12:405-11. [PMID: 21079118 DOI: 10.1001/archfacial.2010.93] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To develop a method to rapidly stabilize the shape change process in peripheral slices of costal cartilage by using infrared laser irradiation in a porcine model. METHODS Forty peripheral porcine costal cartilage specimens (40 × 10 × 2 mm) were harvested. Thirty of these specimens were immediately irradiated with an Nd:YAG laser (λ = 1.32 μm; spot size, 2-mm diameter) using 1 of 3 exposure treatments: 6 W, 2 seconds, and 4 spots; 8 W, 3 seconds, and 4 spots; or 6 W, 2 seconds, and 8 spots. Ten control specimens were only immersed in 0.9% saline solution. Angle of curvature was measured from photographs taken at 0 minutes, immediately after irradiation, and at 30 minutes, 1 hour, 5 hours, and 24 hours. Infrared imaging was used to measure surface temperatures during irradiation. Cell viability after irradiation was determined using a live/dead assay in conjunction with fluorescent confocal microscopy. RESULTS Compared with the untreated controls, the irradiated grafts underwent accelerated shape change within the first 30 minutes to reach a stable geometry. Thereafter, irradiated grafts underwent little or no shape change, whereas the control group exhibited significant change in curvature from 30 minutes to 24 hours (P < .001). The average peak irradiated spot temperatures ranged from 76°C to 82°C. Cell viability measurements at the laser spot sites demonstrated a hemispherically shaped region of dead cells with a depth of 0.8 to 1.2 mm and a surface diameter of 1.9 to 2.7 mm. CONCLUSIONS Laser irradiation of peripheral costal cartilage slices provides an effective method for rapidly stabilizing acute shape change by accelerating the warping process. The temperature elevations necessary to achieve this are spatially limited and well within the limits of tolerable tissue injury.
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Affiliation(s)
- Allen Foulad
- Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Rd E, University of California, Irvine, CA 92612, USA
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Garg R, Shaikh M, Foulad A, Wong B. Chondrocyte viability in human nasal septum after morselization. ACTA ACUST UNITED AC 2010; 12:204-6. [PMID: 20479439 DOI: 10.1001/archfacial.2010.35] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Manuel CT, Foulad A, Protsenko DE, Sepehr A, Wong BJF. Needle electrode-based electromechanical reshaping of cartilage. Ann Biomed Eng 2010; 38:3389-97. [PMID: 20614240 PMCID: PMC2949569 DOI: 10.1007/s10439-010-0088-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 05/26/2010] [Indexed: 01/26/2023]
Abstract
Electromechanical reshaping (EMR) of cartilage provides an alternative to the classic surgical techniques of modifying the shape of facial cartilages. The original embodiment of EMR required surface electrodes to be in direct contact with the entire cartilage region being reshaped. This study evaluates the feasibility of using needle electrode systems for EMR of facial cartilage and evaluates the relationships between electrode configuration, voltage, and application time in effecting shape change. Flat rabbit nasal septal cartilage specimens were deformed by a jig into a 90° bend, while a constant electric voltage was applied to needle electrodes that were inserted into the cartilage. The electrode configuration, voltage (0–7.5 V), and application time (1–9 min) were varied systematically to create the most effective shape change. Electric current and temperature were measured during voltage application, and the resulting specimen shape was assessed in terms of retained bend angle. In order to demonstrate the clinical feasibility of EMR, the most effective and practical settings from the septal cartilage experimentation were used to reshape intact rabbit and pig ears ex vivo. Cell viability of the cartilage after EMR was determined using confocal microscopy in conjunction with a live/dead assay. Overall, cartilage reshaping increased with increased voltage and increased application time. For all electrode configurations and application times tested, heat generation was negligible (<1 °C) up to 6 V. At 6 V, with the most effective electrode configuration, the bend angle began to significantly increase after 2 min of application time and began to plateau above 5 min. As a function of voltage at 2 min of application time, significant reshaping occurred at and above 5 V, with no significant increase in the bend angle between 6 and 7.5 V. In conclusion, electromechanical reshaping of cartilage grafts and intact ears can be effectively performed with negligible temperature elevation and spatially limited cell injury using needle electrodes.
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Affiliation(s)
- Cyrus T Manuel
- Beckman Laser Institute, University of California Irvine, Irvine, CA 92612, USA.
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Garg R, Shaikh M, Foulad A, Wong B. Chondrocyte Viability in Human Nasal Septum After Morselization. ACTA ACUST UNITED AC 2010. [DOI: 10.1001/archfaci.2010.35] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Rohit Garg
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology–Head and Neck Surgery (Drs Garg and Wong), The Beckman Laser Institute (Drs Garg and Wong and Mssrs Shaikh and Foulad), and Departments of Biomedical Engineering and Surgery (Dr Wong), University of California, Irvine
| | - Mohammad Shaikh
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology–Head and Neck Surgery (Drs Garg and Wong), The Beckman Laser Institute (Drs Garg and Wong and Mssrs Shaikh and Foulad), and Departments of Biomedical Engineering and Surgery (Dr Wong), University of California, Irvine
| | - Allen Foulad
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology–Head and Neck Surgery (Drs Garg and Wong), The Beckman Laser Institute (Drs Garg and Wong and Mssrs Shaikh and Foulad), and Departments of Biomedical Engineering and Surgery (Dr Wong), University of California, Irvine
| | - Brian Wong
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology–Head and Neck Surgery (Drs Garg and Wong), The Beckman Laser Institute (Drs Garg and Wong and Mssrs Shaikh and Foulad), and Departments of Biomedical Engineering and Surgery (Dr Wong), University of California, Irvine
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Holden PK, Chlebicki C, Wong BJF. Minimally invasive ear reshaping with a 1450-nm diode laser using cryogen spray cooling in New Zealand white rabbits. ACTA ACUST UNITED AC 2010; 11:399-404. [PMID: 19917901 DOI: 10.1001/archfacial.2009.17] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Otoplasty is the current standard of care for treating prominent ears, a psychologically and sometimes functionally disabling disorder. The technically demanding procedure carries many risks such as poor aesthetic outcome, need for revision surgery, and need for general anesthesia. This study investigates the use of laser irradiation combined with cryogen skin cooling and stenting to reshape cartilage in the ears of New Zealand white rabbits. METHODS In this prospective, randomized, internally controlled animal study, the right ears of 9 rabbits were mechanically deformed with a jig and then irradiated with a 1450-nm diode laser combined with cryogen skin cooling (14 J/pulse with cryogen spray for 33 milliseconds per cycle and a 6-mm spot size). The left ear served as the control. The ears were splinted for 1, 3, or 4 weeks. The rabbits were then given a lethal dose of intravenous pentobarbital, and the splints were removed and ears examined and photographed. Light and confocal microscopy were performed on the specimens. RESULTS Shape change was observed in all 9 treated rabbit ears, while none of the control ears (stenting alone) showed significant change. Qualitatively, reshaped ears were stiffer after 4 weeks of splinting than after 1 or 3 weeks. None of the rabbits showed evidence of skin injury nor did they show signs of postprocedural pain. Findings from histologic analysis in the treated areas showed evidence of an expanded chondrocyte population in the region of laser irradiation, along with some perichondrial thickening and some fibrosis of the deep dermis. Confocal microscopy revealed minimal cellular death at 1 week and none thereafter. CONCLUSIONS Cartilage reshaping using laser energy can be performed safely transcutaneously using cryogen spray cooling in rabbits. This animal model has similarity to human ears with regard to skin and cartilage thickness and is a stepping stone toward developing minimally invasive laser auricle reshaping in humans.
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Affiliation(s)
- Paul K Holden
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine Medical Center, 101 The City Drive, Bldg 56, Ste 500, Orange, CA 92868, USA
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Holden PK, Li C, Da Costa V, Sun CH, Bryant SV, Gardiner DM, Wong BJF. The effects of laser irradiation of cartilage on chondrocyte gene expression and the collagen matrix. Lasers Surg Med 2009; 41:487-91. [PMID: 19639619 DOI: 10.1002/lsm.20795] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVES Laser reshaping of cartilage is an emerging technology aimed at replacing conventional techniques for aesthetic and reconstructive surgery. Little is known about the mechanisms of wound healing following the photothermal heating during laser reshaping and, ultimately, how collagen remodels in the irradiated tissue. Healthy hyaline and elastic cartilage as found in the ear, nose, larynx, and trachea does not express collagen type I which is characteristic of fibro-cartilage and scar tissue. The aim of the study was to determine if collagen I and II gene expression occurs within laser irradiated rabbit septal cartilage. METHODS Nasal septum harvested from freshly euthanized New Zealand White rabbits were irradiated with an Nd:YAG laser. After 2 weeks in culture, the laser spot and surrounding non-irradiated regions were imaged using immunofluorescence staining and evaluated using reverse transcription polymerase chain reaction (RT-PCR) to determine the presence of collagen I and II, and ascertain collagen I and II gene expression, respectively. RESULTS All laser irradiated specimens showed a cessation in collagen II gene expression within the center of the laser spot. Collagen II was expressed in the surrounding region encircling the laser spot and within the non-irradiated periphery in all specimens. Immunohistochemistry identified only type II collagen. Neither collagen I gene expression nor immunoreactivity were identified in any specimens regardless or irradiation parameters. CONCLUSIONS Laser irradiation of rabbit septal cartilage using dosimetry parameters similar to those used in laser reshaping does not result in the detection of either collagen I gene expression or immunoreactivity. Only collagen type II was noted after laser exposure in vitro following cell culture, which suggests that the cellular response to laser irradiation is distinct from that observed in conventional wound healing. Laser irradiation of cartilage can leave an intact collagen matrix which likely allows chondrocyte recovery on an intact scaffold.
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Affiliation(s)
- Paul K Holden
- Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, California 92612, USA
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