Comparative Analyses and Ablation Efficiency of Thulium Fiber Laser by Stone Composition

No AccessJournal of UrologyOriginal Research Articles1 Mar 2024Comparative Analyses and Ablation Efficiency of Thulium Fiber Laser by Stone CompositionThis article is commented on by the following:Editorial Comment Jeffrey Johnson, Justin Lee, Miyad Movassaghi, David Han, Srinath-Reddi Pingle, James Williams, Michael Schulster, Prakash Gorroochurn, Yinming Shao, and Ojas Shah Jeffrey JohnsonJeffrey Johnson https://orcid.org/0000-0001-6866-7117 , Justin LeeJustin Lee , Miyad MovassaghiMiyad Movassaghi , David HanDavid Han , Srinath-Reddi PingleSrinath-Reddi Pingle , James WilliamsJames Williams , Michael SchulsterMichael Schulster , Prakash GorroochurnPrakash Gorroochurn , Yinming ShaoYinming Shao , and Ojas ShahOjas Shah Corresponding Author: Ojas Shah, MD, Columbia University Irving Medical Center, 161 Fort Washington Ave, 11th Floor, New York, NY 10032 ( ([email protected]) View All Author Informationhttps://doi.org/10.1097/JU.0000000000003833AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract Purpose: There are limited data on ablation effects of thulium fiber laser (TFL) settings with varying stone composition. Similarly, little is known surrounding the photothermal effects of TFL lithotripsy regarding the chemical and structural changes after visible char formation. We aim to understand the TFL's ablative efficiency across various stone types and laser settings, while simultaneously investigating the photothermal effects of TFL lithotripsy. Materials and Methods: Human specimens of calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, struvite, cystine, carbonate apatite, and brushite stones were ablated using 13 prespecified settings with the Coloplast TFL Drive. Pre- and postablation mass, ablation time, and total energy were recorded. Qualitative ablative observations were recorded at 1-minute intervals with photographs and gross description. Samples were analyzed with Fourier-transform infrared spectroscopy pre- and postablation and electron microscopy postablation to assess the photothermal effects of TFL. Results: Across all settings and stone types, 0.05 J × 1000 Hz was the best numerically efficient ablation setting. When selected for more clinically relevant laser settings (ie, 10-20 W), 0.2 J × 100 Hz, short pulse was the most numerically efficient setting for calcium oxalate dihydrate, cystine, and struvite stones. Calcium oxalate monohydrate ablated with the best numerical efficiency at 0.4 J × 40 Hz, short pulse. Uric acid and carbonate apatite stones ablated with the best numerical efficiency at 0.3 J × 60 Hz, short pulse. Brushite stones ablated with the best numerical efficiency at 0.5 J × 30 Hz, short pulse. Pulse duration impacted ablation effectiveness greatly with 6/8 (75%) of inadequate ablations occurring in medium or long pulse settings. The average percent of mass lost during ablation was 57%; cystine stones averaged the highest percent mass lost at 71%. Charring was observed in 36/91 (40%) specimens. Charring was most often seen in uric acid, cystine, and brushite stones across all laser settings. Electron microscopy of char demonstrated a porous melting effect different to that of brittle fracture. Fourier-transform infrared spectroscopy of brushite char demonstrated a chemical composition change to amorphous calcium phosphate. Conclusions: We describe the optimal ablation settings based on stone composition, which may guide urologists towards more stone-specific care when using thulium laser for treating renal stones (lower energy settings would be safer for ureteral stones). For patients with unknown stone composition, lasers can be preset to target common stone types or adjusted based on visual cues. We recommend using short pulse for all TFL lithotripsy of calculi and altering the settings based on visual cues and efficiency to minimize the charring, an effect which can make the stone refractory to further dusting and fragmentation. REFERENCES 1. . 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Pulse-modulated holmium:YAG laser vs the thulium fiber laser for renal and ureteral stones: a single-center prospective randomized clinical trial. J Urol. 2023; 209(2):374-383. Link, Google Scholar Recusal: Dr Anderson, assistant editor of The Journal of Urology®, was recused from the editorial and peer review processes due to affiliation with Columbia University Medical Center. Support: Funding for the study and the TFL Drive laser were provided by Coloplast for an investigator-initiated trial. Conflict of Interest Disclosures: O.S. is a consultant to Coloplast. All other authors have nothing to disclose. Ethics Statement: In lieu of a formal ethics committee, the principles of the Helsinki Declaration were followed. Author Contributions: Conception and design: J.J., M.M., M.S., O.S.; Data analysis and interpretation: J.J., M.M., D.H., J.W., M.S., P.G., O.S.; Data acquisition: J.J., J.L., M.M., D.H., S.-R. P., J.W., M.S., Y.S., O.S.; Critical revision of the manuscript for scientific and factual content: J.J., J.L., M.M., D.H., S.-R. P., J.W., M.S., P.G., Y.S., O.S.; Drafting the manuscript: J.J., J.L., M.M., D.H., M.S., O.S.; Statistical analysis: D.H., M.S., P.G., Y.S.; Supervision: J.J., J.L., M.M., S.-R. P., J.W., M.S., O.S. Data Availability: Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study. © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetailsCited byTeichman J, Katta N and Milner T (2024) Editorial CommentJournal of Urology, VOL. 211, NO. 3, (454-454), Online publication date: 1-Mar-2024.Related articlesJournal of Urology15 Jan 2024Editorial Comment Volume 211Issue 3March 2024Page: 445-454Supplementary Materials Peer Review Report Open Peer Review Report Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.Keywordsthulium fiber lasernephrolithiasislithotripsyMetrics Author Information Jeffrey Johnson More articles by this author Justin Lee More articles by this author Miyad Movassaghi More articles by this author David Han More articles by this author Srinath-Reddi Pingle More articles by this author James Williams More articles by this author Michael Schulster More articles by this author Prakash Gorroochurn More articles by this author Yinming Shao More articles by this author Ojas Shah Corresponding Author: Ojas Shah, MD, Columbia University Irving Medical Center, 161 Fort Washington Ave, 11th Floor, New York, NY 10032 ( ([email protected]) More articles by this author Expand All Recusal: Dr Anderson, assistant editor of The Journal of Urology®, was recused from the editorial and peer review processes due to affiliation with Columbia University Medical Center. Support: Funding for the study and the TFL Drive laser were provided by Coloplast for an investigator-initiated trial. Conflict of Interest Disclosures: O.S. is a consultant to Coloplast. All other authors have nothing to disclose. Ethics Statement: In lieu of a formal ethics committee, the principles of the Helsinki Declaration were followed. Author Contributions: Conception and design: J.J., M.M., M.S., O.S.; Data analysis and interpretation: J.J., M.M., D.H., J.W., M.S., P.G., O.S.; Data acquisition: J.J., J.L., M.M., D.H., S.-R. P., J.W., M.S., Y.S., O.S.; Critical revision of the manuscript for scientific and factual content: J.J., J.L., M.M., D.H., S.-R. P., J.W., M.S., P.G., Y.S., O.S.; Drafting the manuscript: J.J., J.L., M.M., D.H., M.S., O.S.; Statistical analysis: D.H., M.S., P.G., Y.S.; Supervision: J.J., J.L., M.M., S.-R. P., J.W., M.S., O.S. Data Availability: Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study. Advertisement PDF downloadLoading ...