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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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Guo F, Yu X, Jiang H. [Current progress of laser-assisted cartilage reshaping for prominent ear]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2018; 32:769-772. [PMID: 29905059 DOI: 10.7507/1002-1892.201712074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Objective To summarize the current progress of laser-assisted cartilage reshaping (LACR) for prominent ear. Methods The domestic and abroad article concerning the LACR in treatment of prominent ear was reviewed and analyzed. Results As a new technique, there were three types of LACR therapies that been used for prominent ear. LACR with the 1 064 nm Nd/YAG laser is painful and the penetration depth of the 1 064 nm Nd/YAG laser is greater than that of the 1540 nm Er/Glass laser which is caused more tissue injury. LACR with the 1 540 nm Er/Glass laser has high absorption by the ear cartilage and produce less injury to the surrounding tissue. Use of the CO 2 laser permitted cartilage reshaping combined with both vaporization and incisions, which complicates the technique, although, with low recurrence rate and definite effect. Insisting on wearing ear mold is the key to get satisfactory effectiveness for postoperative patients. The complications of LACR for prominent ear, such as the dermatitis, perforation of the skin, hematoma, or infection, should be noticed. Conclusion Application of LACR for prominent ear just has a short period of time, limited number of cases, and few relevant literature reports. Its effectiveness needs to be further studied and clarified.
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Affiliation(s)
- Fengfeng Guo
- The Seventh Department of Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100144, P.R.China
| | - Xiaobo Yu
- The Seventh Department of Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100144, P.R.China
| | - Haiyue Jiang
- The Seventh Department of Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100144,
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Chu EA, Li M, Lazarow FB, Wong BJF. Mid-infrared laser orbital septal tightening: ex vivo dosimetry study and pilot clinical study. JAMA FACIAL PLAST SU 2016; 16:425-31. [PMID: 25275274 DOI: 10.1001/jamafacial.2014.671] [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
IMPORTANCE Blepharoplasty is one of the most commonly performed facial aesthetic surgeries. While myriad techniques exist to improve the appearance of the lower eyelids, there is no clear consensus on the optimal management of the orbital septum. OBJECTIVES To evaluate the safety and feasibility of the use of the holmium:yttrium aluminum garnet (Ho:YAG) laser for orbital septal tightening, and to determine whether modest use of this laser would provide some degree of clinical efficacy. DESIGN, SETTING, AND PARTICIPANTS Direct laser irradiation of ex vivo bovine tissue was used to determine appropriate laser dosimetry using infrared thermal imaging and optical coherence tomography before conducting a pilot clinical study in 5 patients. Laser irradiation of the lower eyelid orbital septum was performed through a transconjunctival approach. Standardized preoperative and postoperative photographs were taken for each patient and evaluated by 6 unbiased aesthetic surgeons. EXPOSURE Use of the Ho:YAG laser for orbital septal tightening. MAIN OUTCOME AND MEASURE To determine appropriate laser dosimetry, infrared thermal imaging and optical coherence tomography were used to monitor temperature and tissue shape changes of ex vivo bovine tissue that was subjected to direct laser irradiation. For the clinical study, preoperative and postoperative photographs were evaluated by 6 surgeons on a 10-point Likert scale. RESULTS Optical coherence tomography demonstrated that laser irradiation of bovine tissue to a temperature range of 60°C to 80°C resulted in an increase in thickness of up to 2-fold. There were no complications or adverse cosmetic outcomes in the patient study. Patient satisfaction with the results of surgery averaged 7 on a 10-point Likert scale. For 3 patients, 3 (50%) of the evaluators believed there was a mild improvement in appearance of the lower eyelids after surgery. The remaining patients were thought to have no significant changes. CONCLUSIONS AND RELEVANCE Transconjunctival Ho:YAG laser blepharoplasty is a safe procedure that may ameliorate mild pseudoherniation of lower eyelid orbital fat and is a first step toward the development of percutaneous techniques.
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Affiliation(s)
- Eugene A Chu
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine School of Medicine, Irvine
| | - Michael Li
- Beckman Laser Institute, University of California, Irvine
| | | | - Brian J F Wong
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine School of Medicine, Irvine2Beckman Laser Institute, University of California, Irvine
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Leclère FM, Vogt PM, Casoli V, Vlachos S, Mordon S. Laser-assisted cartilage reshaping for protruding ears: A review of the clinical applications. Laryngoscope 2015; 125:2067-71. [PMID: 25891156 DOI: 10.1002/lary.25260] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2015] [Indexed: 11/11/2022]
Abstract
OBJECTIVES/HYPOTHESIS In 2006, our institute reported the first clinical use of laser-assisted cartilage reshaping (LACR) for protruding ears. Since then, the technique has been developed and refined. This article reviews the literature on the clinical application of LACR. STUDY DESIGN Literature review. METHODS A MEDLINE literature search was performed on LACR combined with cross-referencing. The period of search was 1993 to 2014. Search terms used were: laser, cartilage reshaping, protruding ears, LACR. RESULTS Only seven clinical studies using three different wavelengths were found in the literature: 1,064 nm (Nd:YAG), 10,600 nm (CO2), and 1540 nm (Er:Glass). Clinical outcomes, laser wavelength and parameters, and patient satisfaction are discussed in each case. CONCLUSIONS The success rate for ear reshaping achieved with LACR appears promising. The use of this noninvasive technique will increase in the near future.
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Affiliation(s)
- Franck Marie Leclère
- Department of Plastic and Transsexual Surgery, Burn Surgery, Hand Surgery, CHU University of Bordeaux, Pellegrin Hospital Group, Bordeaux, France.,Department of Plastic Surgery, Hannover Medical School, Hannover, Germany.,French Institute of Health and Medical Research U703, University of Lille, Lille, France
| | - Peter M Vogt
- Department of Plastic Surgery, Hannover Medical School, Hannover, Germany
| | - Vincent Casoli
- Department of Plastic and Transsexual Surgery, Burn Surgery, Hand Surgery, CHU University of Bordeaux, Pellegrin Hospital Group, Bordeaux, France
| | - Spiros Vlachos
- Department of Plastic Surgery , Private Hospital, Athens, Greece
| | - Serge Mordon
- French Institute of Health and Medical Research U703, University of Lille, Lille, France
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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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Zemek AJ, Protsenko DE, Wong BJ. Mechanical properties of porcine cartilage after uniform RF heating. Lasers Surg Med 2012; 44:572-9. [PMID: 22886463 PMCID: PMC4141677 DOI: 10.1002/lsm.22057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2012] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVES Thermally mediated modalities of cartilage reshaping utilize localized heating of cartilage combined with mechanical deformation to achieve new geometries. We sought to determine the steady state elastic modulus of thermally modified cartilage without deformation, as this provides a constraint in mechanical models of the shape change process. STUDY DESIGN/MATERIALS AND METHODS The main objective of this study was to characterize the steady state elastic modulus of porcine septal cartilage after uniform heating with radiofrequency (RF) to peak temperatures of 50 ± 5, 65 ± 5, and 85 ± 5°C. The cartilage was divided into three equally sized regions, designated as anterior, middle and posterior. Each region was then sectioned into two specimens with the proximal component serving as a paired control. RESULTS The data confirm that there is high baseline variability in control steady state elastic moduli between animals. Also, the control values confirm a decreasing steady state elastic modulus from anterior to posterior. There is no statistical significance (P > 0.05) found between the elastic moduli of control and treated samples. CONCLUSIONS Although shape change and retention have been fairly well characterized, little is known about the specific relation between steady state elastic modulus of cartilage and maximum treatment temperature. We determined that the difference of steady state elastic modulus between control and treated porcine septal samples was not statistically significant after uniform heating with RF to peak temperatures of 50 ± 5, 65 ± 5, and 85 ± 5°C. Ultimately, the results of this study do not pertain to the regions of heated cartilage that are shaped to hold a new form; however, it does show that the regions that are not mechanically deformed do return to the original pre-treatment elastic modulus. This is still useful information that may be used in finite element models to predict changes in internal stress distributions of cartilage after laser reshaping.
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Affiliation(s)
- Allison J. Zemek
- Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, California 92697
- Department of Biomedical Engineering, University of California Irvine, Irvine, California 92697
| | - Dmitry E. Protsenko
- Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, California 92697
- Department of Biomedical Engineering, University of California Irvine, Irvine, California 92697
| | - Brian J.F. Wong
- Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, California 92697
- Department of Biomedical Engineering, University of California Irvine, Irvine, California 92697
- Division of Facial Plastic Surgery, Department of Otolaryngology—Head and Neck Surgery, University of California Irvine, Orange, California 92697
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Wu EC, Protsenko DE, Khan AZ, Dubin S, Karimi K, Wong BJF. Needle electrode-based electromechanical reshaping of rabbit septal cartilage: a systematic evaluation. IEEE Trans Biomed Eng 2011; 58. [PMID: 21606017 DOI: 10.1109/tbme.2011.2157155] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electromechanical reshaping (EMR) provides a means of producing shape change in cartilage by initiating oxidation-reduction reactions in mechanically deformed specimens. This study evaluates the effect of voltage and application time on specimen shape change using needle electrodes. Rabbit septal cartilage specimens (20 x 8 x 1 mm, n = 200) were bent 90 degrees in a precision-machined plastic jig. Optimal electrode placement and the range of applied voltages were estimated using numerical modeling of the initial electric field within the cartilage sample. A geometric configuration of three platinum needle electrodes 2 mm apart from each other and inserted 6 mm from the bend axis on opposite ends was selected. One row of electrodes served as the anode and the other as the cathode. Constant voltage was applied at 1, 2, 4, 6, and 8 V for 1, 2, and 4 minutes, followed by rehydration in phosphate buffered saline. Samples were then removed from the jig and bend angle was measured. In accordance with previous studies, bend angle increased with increasing voltage and application time. Below a voltage threshold of 4 V, 4 minutes, no clinically significant reshaping was observed. The maximum bend angle obtained was 35.7 ± 1.7 º at 8 V, 4 minutes.
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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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Denton ML, Noojin GD, Foltz MS, Clark CD, Estlack LE, Rockwell BA, Thomas RJ. Spatially correlated microthermography maps threshold temperature in laser-induced damage. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:036003. [PMID: 21456867 DOI: 10.1117/1.3548881] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We measured threshold temperatures for cell death resulting from short (0.1-1.0 s) 514-nm laser exposures using an in vitro retinal model. Real-time thermal imaging at sub-cellular resolution provides temperature information that is spatially correlated with cells at the boundary of cell death, as indicate by post-exposure fluorescence images. Our measurements indicate markedly similar temperatures, not only around individual boundaries (single exposure), but among all exposures of the same duration in a laser irradiance-independent fashion. Two different methods yield similar threshold temperatures with low variance. Considering the experimental uncertainties associated with the thermal camera, an average peak temperature of 53 ± 2 °C is found for laser exposures of 0.1, 0.25, and 1.0 s. Additionally, we find a linear relationship between laser exposure duration and time-averaged integrated temperature. The mean thermal profiles for cells at the boundary of death were assessed using the Arrhenius rate law using parameter sets (frequency factor and energy of activation) found in three different articles.
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Affiliation(s)
- Michael L Denton
- TASC, Inc., Biomedical Sciences and Technology Department, San Antonio, Texas 78235, 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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Protsenko DE, Ho K, Wong BJF. Survival of chondrocytes in rabbit septal cartilage after electromechanical reshaping. Ann Biomed Eng 2010; 39:66-74. [PMID: 20842431 PMCID: PMC3010201 DOI: 10.1007/s10439-010-0139-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Accepted: 07/30/2010] [Indexed: 11/24/2022]
Abstract
Electromechanical reshaping (EMR) has been recently described as an alternative method for reshaping facial cartilage without the need for incisions or sutures. This study focuses on determining the short- and long-term viability of chondrocytes following EMR in cartilage grafts maintained in tissue culture. Flat rabbit nasal septal cartilage specimens were bent into semi-cylindrical shapes by an aluminum jig while a constant electric voltage was applied across the concave and convex surfaces. After EMR, specimens were maintained in culture media for 64 days. Over this time period, specimens were serially biopsied and then stained with a fluorescent live–dead assay system and imaged using laser scanning confocal microscopy. In addition, the fraction of viable chondrocytes was measured, correlated with voltage, voltage application time, electric field configuration, and examined serially. The fraction of viable chondrocytes decreased with voltage and application time. High local electric field intensity and proximity to the positive electrode also focally reduced chondrocyte viability. The density of viable chondrocytes decreased over time and reached a steady state after 2–4 weeks. Viable cells were concentrated within the central region of the specimen. Approximately 20% of original chondrocytes remained viable after reshaping with optimal voltage and application time parameters and compared favorably with conventional surgical shape change techniques such as morselization.
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Affiliation(s)
- Dmitry E Protsenko
- Beckman Laser Institute, University of California Irvine, Irvine, CA, USA.
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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: 20] [Impact Index Per Article: 1.3] [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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Chae Y, Protsenko D, Holden PK, Chlebicki C, Wong BJF. Thermoforming of tracheal cartilage: viability, shape change, and mechanical behavior. Lasers Surg Med 2009; 40:550-61. [PMID: 18798288 DOI: 10.1002/lsm.20666] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVES Trauma, emergent tracheostomy, and prolonged intubation are common causes of severe deformation and narrowing of the trachea. Laser technology may be used to reshape tracheal cartilage using minimally invasive methods. The objectives of this study were to determine: (1) the dependence of tracheal cartilage shape change on temperature and laser dosimetry using heated saline bath immersion and laser irradiation, respectively, (2) the effect of temperature on the mechanical behavior of cartilage, and (3) tissue viability as a function of laser dosimetry. MATERIALS AND METHODS Ex vivo rabbit trachea cartilage specimens were bent and secured around a cylinder (6 mm), and then immersed in a saline bath (45 and 72 degrees C) for 5-100 seconds. In separate experiments, tracheal specimens were irradiated with a diode laser (lambda = 1.45 microm, 220-400 J/cm(2)). Mechanical analysis was then used to determine the elastic modulus in tension after irradiation. Fluorescent viability assays combined with laser scanning confocal microscopy (LSCM) were employed to image and identify thermal injury regions. RESULTS Shape change transition zones, between 62 and 66 degrees C in the saline heating bath and above power densities of 350 J/cm(2) (peak temperatures 65+/-10 degrees C) for laser irradiation were identified. Above these zones, the elastic moduli were higher (8.2+/-4 MPa) than at lower temperatures (4.5+/-3 MPa). LSCM identified significant loss of viable chondrocytes within the laser-irradiation zones. CONCLUSION Our results indicate a change in mechanical properties occurs with laser irradiation and further demonstrates that significant thermal damage is concurrent with clinically relevant shape change in the elastic cartilage tissues of the rabbit trachea using the present laser and dosimetry parameters.
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Affiliation(s)
- Yongseok Chae
- The Beckman Laser Institute, 1002 Health Sciences Rd East, Irvine, California 92697, USA.
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Choi IS, Chae YS, Zemek A, Protsenko DE, Wong B. Viability of human septal cartilage after 1.45 microm diode laser irradiation. Lasers Surg Med 2009; 40:562-9. [PMID: 18798294 DOI: 10.1002/lsm.20663] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND AND OBJECTIVES Chondrocyte viability following laser irradiation and reshaping has not been established for human nasal septal cartilage. Knowledge of the relationship between thermal injury and laser dosimetry is needed in order to optimize septal laser cartilage reshaping. The objective of this study was to determine the depth and width of thermal injury in human septal cartilage following laser irradiation. STUDY DESIGN/MATERIALS AND METHODS Excess fresh nasal septal cartilage sections from rhinoplasty or septoplasty operations were irradiated using a 1.45 microm diode laser 1.25-3.6 W (2.8 mm spot diameter) with 1 second fixed exposure time, and then at exposure times of 1-4 seconds for a fixed power of 1.25 W. An infrared camera recorded surface temperature profiles during irradiation, and the temperature data were incorporated into a rate process model to numerically estimate thermal damage. Calcein AM and ethidium homodimer-1 fluorescent dyes combined with confocal laser microscopy (CLM) were used to measure thermal damage. RESULTS CLM demonstrated clear demarcation between dead and living cells following irradiation. The extent of non-viable chondrocyte distributions increased with power and exposure time. The maximum depths of injury were 1,012 and 1,372 microm after 3.6 W 1 second and 1.25 W 4 seconds irradiation respectively. The damage predictions made by the rate process model underestimated thermal injury when compared with CLM measurements. CONCLUSIONS The assay system identified regions of non-viable chondrocytes in human septal cartilage and defined how thermal injury varies with dosimetry when using a 1.45 microm diode laser.
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Affiliation(s)
- Ick-Soo Choi
- Department of Otolaryngology, Head and Neck Surgery, Seoul Paik Hospital, Inje University, 5 Mareunnae Gil, Jung Gu, Seoul 100032, Korea.
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Abstract
Lasers and optical technologies play a significant role in aesthetic and reconstructive surgery. The unique ability of optical technologies to target specific structures and layers in tissues to effect chemical, mechanical, or thermal changes makes them a powerful tool in cutaneous rejuvenation, hair removal, fat removal, and treatment of vascular lesions such as port-wine stains, among many other procedures. With the development of adjunct techniques such as epidermal cooling, lasers and optical technologies have become more versatile and safe. The constant improvement of existing applications and the emergence of novel applications such as photodynamic therapy, nanoparticles, spectroscopy, and noninvasive imaging continue to revolutionize aesthetic medicine by offering a minimally invasive alternative to traditional surgery. In the future, therapies will be based on individualized, maximum, safe radiant exposure to deliver optimal dosimetry. Lasers and optical technologies are headed toward safer, easier, more quantifiable, and more individualized therapy.
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Affiliation(s)
- Edward C Wu
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, 1002 Health Sciences Rd E, Irvine, CA 92612, USA
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Protsenko DE, Wong BJF. Engineering of a straighter septum: numerical model of mechanical stress relaxation in laser-heated septal cartilage. ACTA ACUST UNITED AC 2008; 2007:5399-402. [PMID: 18003229 DOI: 10.1109/iembs.2007.4353563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVES Successful application of laser cartilage reshaping (LCR) for the in-situ treatment of structural deformities in the nasal septum has generated increasing clinical interest, because septoplasty is among the top five most common operations performed. However, few studies have investigated stress fields existing in the nasal septal cartilage during LCR of septal deviations. The objectives of this study were to: (1) formulate a finite-element model describing stress fields in mechanically straightened septum, (2) calculate stress fields in the septum after a given pattern of laser irradiation produced thermally induced stress relaxation in selected sites, and (3) investigate the dependence of the overall stress relaxation in a straightened septum as a function of the number, location and size of laser irradiation sites. METHODS The cartilagenous nasal septum was modeled as 24 x 24 x 1.5 mm slab. The deviation was represented as a bulge in the center of the septum with a maximum elevation above the surface of 2 mm. A straightening deformation was represented in form of displacement boundary condition applied to the bulge. Laser irradiation applied in a rectangular pattern of several spots was assumed. The effect of thermally induced stress relaxation was modeled as a simultaneous change in the cartilage mechanical properties and reduction of strain occurring within irradiated spots according to the heating history. The finite-element method was used to calculate stress fields within the straightened septum and the force of reaction to the straightening deformation before and after laser irradiation. RESULTS Straightening deformation produced a highly non-homogeneous stress field with both regions of tension and compression present. Reaction force decreased with increasing number of irradiation sites and delivered laser energy. The model predicts that laser irradiation reducing reaction force by approximately 95% results in approximately 50% thermal damage to septal cartilage. CONCLUSIONS A numerical model of stress fields in laser-reshaped deviated septum has been developed. The model shows highly non-homogeneous stress distributions before and after laser treatment. The model predicts that sufficiently high reduction of reaction force can be obtained with a localized laser treatment.
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Miyazaki H, Kato J, Kakizaki H, Nagata T, Uetake H, Okudera H, Watanabe H, Hashimoto K, Omura K. Submucosal glycerol injection-assisted laser surgical treatment of oral lesions. Lasers Med Sci 2007; 24:13-9. [PMID: 18049794 DOI: 10.1007/s10103-007-0514-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 10/09/2007] [Indexed: 01/03/2023]
Abstract
Recently, we modified laser surgery for superficial lesions in the oral cavity by using submucosal glycerol injection. This procedure was based on a technique for endoscopic mucosal resection (EMR) in the gastrointestinal tract. The aim of this study was to evaluate the effectiveness of the modified laser surgery assisted by a submucosal glycerol injection. Eleven superficial oral lesions in ten patients were treated with diode laser (continuous wave mode, 3 W) after a submucosal injection of glycerol solution. Injection of glycerol solution created mucosal expansion, which enabled the procedures to be done without bleeding, over cutting, over coagulation and unintended irradiation. The surface of the wounds showed little carbonization, resulting in good healing. Submucosal glycerol injection for laser treatment in the oral cavity is a promising technique for treating superficial oral lesions by virtue of less invasion and good results.
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Affiliation(s)
- Hidetaka Miyazaki
- Oral and Maxillofacial Surgery, Department of Oral Restitution, Graduate School, Tokyo Medical and Dental University,Tokyo, Japan.
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