Chemical, Chromatographic and Electron Microscopic Analysis of the Bubbles Emerging During Holmium:YAG Laser Lithotripsy of Cystine Stone

Chemical, Chromatographic and Electron Microscopic Analysis of the Bubbles Emerging During Holmium:YAG Laser Lithotripsy of Cystine Stone | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Chemical, Chromatographic and Electron Microscopic Analysis of the Bubbles Emerging During Holmium:YAG Laser Lithotripsy of Cystine Stone Muzaffer Tansel Kılınç, Mehmet Serkan Özkent, Yunus Emre Göger This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3487502/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Jan, 2024 Read the published version in Urolithiasis → Version 1 posted 7 You are reading this latest preprint version Abstract The primary aim of the present in vitro study is to analyze the chemical content of the bubbles occurring during the fragmentation of cystine stone with high-power and low-power Ho:YAG laser. The secondary aim of our study is to discuss their clinical importance. Human renal calculi (calcium oxalate monohydrate (COM), cystine, and uric acid) were fragmanted with low-power and high-power Ho:YAG laser in separate experimental setups at room temprature, and it was observed whether the gas production during this time. After laser lithotripsy, a cloudy colored gas was obtained only fragmentation of cystine stone. Qualitative gas content analysed performed with Gas chromatography–mass spectrometry device. In addition, the fragments in the aqueous cystine calculi setup were dried and taken to the laboratory to be examined with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction analysis. No gas production was observed after fragmentation in the COM and uric acid stone. Free cystine, sulfur, thiophene, and hydrogen sulfide gas were produced by low-power and high-power Ho:YAG laser lithotripsy of cystine stone. In SEM-EDX mapping analysis, free cystine molecule containing 42.8% sulfur (S), 21% oxygen (O), 14.9% carbon (C), 21% nitrogen (N) atom was detected in the cystine stone experimental setup. The evidence obtained that hydrogen sulfide emerges in the gaseous environment during Ho:YAG laser fragmentation of cystine stone requires caution against the risk of in vivo production and toxicity. Chemical Decomposition Chromatographic Analysis Cystine Stone Holmium:YAG Laser Photothermal Ablative Mechanism Toxicity Figures Figure 1 Figure 2 Figure 3 Figure 4 INTRODUCTION Cystinuria is an autosomal recessive disease characterized by defective reabsorption of cystine and dibasic amino acids in the renal proximal tubule. The high concentration of cystine in the urine and its low solubility at normal urinary pH may result in cystine stone formation. Cystine stones constitute 1–3% of urinary system stones in adults and 6–8% in children [ 1 ]. Although the frequency of cystine stones is low, they constitute an important health problem due to high rates of recurrence and surgical interventions [ 2 ]. Patients have an increased risk of kidney damage due to recurrent surgical interventions and episodes of obstruction. Therefore, management and treatment of cystine stones is of vital importance especially in children. Retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PNL) are often used in the endourological treatment of renal cystine stones, and the holmium: yttrium-aluminium-garnet (Ho:YAG) laser is extensively used lithotripter device [ 3 , 4 ]. Adjustable power settings and high absorption peak in water at a wavelength of 2140 nm make the Ho:YAG laser is the most employed, safe, and effective lithotripsy system in urolithiasis [ 5 ]. The Ho:YAG laser causes stone fragmentation by photoacoustic and photothermal ablative mechanism [ 6 ]. The photoacoustic mechanism is based on the fragmentation of the stone by the shock wave produced during plasma expansion and bubble collapse with laser energy. In the photothermal ablative mechanism, the stone surface heats up to a thermal threshold with laser energy and fragmentation occurs. It has been proven in the study of Chan et al. that the dominant mechanism in stone fragmentation in the Ho:YAG laser is the photothermal ablative mechanism [ 7 ]. This mechanism may cause a change in the chemical structure of the stone and the formation of by-products. For example, Teichman et al. showed in their in vitro study that Ho:YAG laser lithotripsy of uric acid stones produced cyanide [ 8 ]. Cyanide inhibits oxidative phosphorylation and cellular ATP synthesis [ 9 ]. This can result in clinical manifestations ranging from dizziness, headache to lethal cardiac arrhythmia and hypoxia [ 10 ]. The emergence of potentially toxic by-products for the patient and operating room personnel raises additional safety issues in Ho:YAG laser lithotripsy. Similarly, chemical structure changes also occur in cystine stone during Ho:YAG laser lithotripsy [ 7 ]. In previous studies, it has been stated that free cysteine, cystine, and free sulfur were detected in the aqueous medium after in-vitro laser fragmentation of cystine stone [ 7 , 11 ]. In the clinical observation of most urologists, visible bubbles occur during the fragmentation of cystine stone with Ho:YAG laser. These bubbles appear as cloudy white, hydrophobic bubbles in the saline and recognized by most urologists for their specific "rotten egg odor". According to our best knowledge, currently there is not any study in the relevant literature about the chemical content of these bubbles and discussing their clinical importance. The primary aim of the present in vitro study is to analyze the chemical content of the bubbles occurring during the fragmentation of cystine stone with high-power and low-power Ho:YAG laser. The secondary aim of our study is to discuss their clinical importance. MATERIALS AND METHODS In vitro cystine stone fragmentation, experimental setup and gas extraction: Human renal calculi (calcium oxalate monohydrate (COM), cystine, and uric acid) were obtained from Necmettin Erbakan University Urology clinic. Stone analyzes were performed by X-ray diffraction analysis before the in vitro fragmentation. The calculi were placed into the sterile biochemistry tubes separately, full-filled with sterile 0.9% sodium chloride solution. Tube and luer lock connector are integrated to each other with airtight latex material. 270 micron Ho:YAG laser fiber was passed through the connector and placed in a way that it would contact the stone. The air tightness of each experimental setup was confirmed with a leak tester (Karl Storz, Tuttlingen, Germany). Then, a 5-cc injector was placed to the connector to obtain the bubbles after laser fragmentation (Fig. 1 a). COM, cystine, and uric acid calculi were fragmented with low-power and high-power Ho:YAG laser in separate experimental setups at room temperature, and it was observed whether the injector was filled with gas during this time. In order to avoid evaporation of the water in the sodium chloride solution, a rise in the temperature of more than 10°C during the fragmentation was prevented. Low-power Ho:YAG laser (Energy settings: 1 joule/pulse at 8 Hz, 30-Watts, Medilas H Solvo®, Dornier MedTech Europe GmbH, Wessling, Germany) and high-power Ho:YAG laser (Energy settings: 1 joule/pulse at 50 Hz, 150- Watts, MultiPulse HoPlus, Jena Surgical, Jena, Germany) were used for laser fragmentation. After both low-power laser and high-power laser lithotripsy, a cloudy colored gas was obtained only fragmentation of cystine stone (Fig. 1 b). After the gas was injected into the airtight screw top clear vials (Agilent Technologies, Santa Clara, Palo Alto, CA, USA) it was immediately taken to the gas chromatography laboratory. In addition, the fragments in the aqueous cystine calculi setup were dried and taken to the laboratory to be examined with scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction analysis. Gas chromatography–mass spectrometry (GC/MS) analysis: An Agilent 7890B GC System (Santa Clara, Palo Alto, CA, USA) equipped with an Agilent Technologies GC Sampler 80 Autosampler and an Agilent J&W DB-WAX GC Column, 60 m, 0.25 mm, 0.25 µm was used. Moreover, headspace sampling was used for analysis. The following conditions were set for the oven: 35°C, maintain for 6 min; 35–50°C at intervals of 2°C/min, hold for 5 min; 50–80°C at intervals of 5°C/min, hold for 5 min. The temperature at the inlet was set to 240°C. With a 3.0 mL/min flow rate, 99.999% pure helium was used as the carrier gas for chromatographic analysis. An injection volume of 1 mL was analyzed in the split mode (10:1). The interface MS temperature was set to 230°C. The detection was performed with an Agilent 5977A MSD mass spectrometer (Santa Clara, Palo Alto, CA, USA), operating in the electron ionization mode (EI) at 70 eV. The selected ion monitoring (SIM) mode was used to acquire the Hydrogen sulfide (H 2 S) signal at m/z 34 and 32. The ion m/z 32 and 34 was also investigated during the simultaneous scan monitoring to guarantee H 2 S identification. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX): Dried fragments were directly mounted on specimen stubs via double sided adhesive discs, and then coated with gold in a Poleron SC7620 sputter coater for the SEM studies. Micrographs were taken with a Zeiss LS-10. SEM–EDX was carried out on a Zeiss LS-10 SEM operating at 15 kV with a probe current of 2500 pA to which a Bruker AXS detector EDX system had been interfaced. Ethics and Consent to Participate: All procedures performed in this study were conducted in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Necmettin Erbakan University Meram Faculty of Medicine Ethics Committee granted the consent, in line with the Helsinki declaration, before the onset of the study (No: 2021/3450). RESULTS No gas production was observed after fragmentation in the COM and uric acid stone experimental setup. In the cystine stone experimental setup, gas output was observed after fragmentation with both low power and high power Ho:YAG laser, and analyzed separately. Qualitative content analysis was performed on both samples with GC-MS device. In the scanning analysis performed on the GC-MS device, peaks belonging to 7 components were observed. In the library scanning on these peaks, high quality content was detected in the 3rd and 7th peaks. It was determined that the 3rd peak belonged to H 2 S (Retention time 6.106 minutes, Quality 64%) and the 7th peak belonged to Thiophene (C 2 H 4 S, Retention time 19.886 minutes, Quality 95%, Fig. 2 a). In addition, free sulfur was detected in the scan mode. In order to detect H 2 S, the SIM analysis performed after simultaneous scan monitoring, using 34 and 32 ions. In the SIM analysis, peaks belonging to four components were observed. In the library scan, high quality content was found to the 1st and 3rd peaks. Both peaks belonged to H 2 S (Retention time 5.59 and 5.96 minutes, Quality 83%, Fig. 2 b). In SEM-EDX mapping analysis, free cystine molecule containing 42.8% sulfur (S), 21% oxygen (O), 14.9% carbon (C), 21% nitrogen (N) atom was detected in the experimental environment (Fig. 3 ). Cystine molecule was detected in the X-ray diffraction analysis of the dried fragments. DISCUSSION The present in vitro study showed that free cystine, sulfur, thiophene, and hydrogen sulfide gas emerged during low-power and high-power Ho:YAG laser lithotripsy of cystine stones. The clinical significance is that Ho:YAG laser lithotripsy of cystine stone lead to the risk of in vivo hydrogen sulfide production which emerge as cloudy white, hydrophobic bubbles in the kidney during the fragmentation (Fig. 4 ). These, hydrogen sulfide-containing gas bubbles may complicate the surgery and pose a potential risk of toxicity to the patient as well as to the personnel in the operating room. Laser lithotripters have been utilized in urologic surgical interventions for about four decades. Q-switched Nd:YAG (neodymium-doped yttrium aluminum garnet) and pulsed dye laser are the first conventional lasers used in lithotripsy. These lasers cause the plasma expansion and bubble collapse in the aqueous working environment. The shock waves that occur during this plasma expansion and bubble collapse, cause fragmentation of the calculi surface via a mechanical effect [ 12 ]. However, the most important limitation of conventional lasers was their low efficiency to fragmentation of hard calculi such as COM, cystine [ 13 , 14 ]. Currently, the Ho:YAG laser, which is effective in all stone types is the most commonly used laser lithotripter [ 5 , 15 ]. The main lithotripsy mechanism of the Ho:YAG laser, differing from conventional lasers, is its “Photothermal Ablative Mechanism” [ 7 , 16 ]. The Ho:YAG laser energy increases the temperature on the stone surface up to a critical threshold with the vapor channel until chemical breakdown. In other words, the shock wave of the bubbles formed by the laser energy does not play the main role in the fragmentation. Instead, the laser energy is absorbed by the calculus, resulting in a chemical decomposition with thermal energy [ 17 , 18 ]. The shock waves (photoacoustic mechanism) are thought to play a lesser role in stone fragmentation. Therefore, chemical structural changes may occur in stone during the Ho:YAG laser lithotripsy. Observation of the by-products derived from different calculi such as free sulfur and cysteine from cystine calculi, calcium carbonate from calcium oxalate monohydrate calculi, and cyanide from uric acid calculi support this thermo-chemical change [ 19 ]. The production of solid or liquid phase by-products in the working environment as a result of chemical decomposition during Ho:YAG laser fragmentation of cystine stone was previously determined [ 7 , 8 , 17 ]. However, the production of gaseous by-products has not been sufficiently investigated. The accumulation of hydrogen sulfide containing hydrophobic gas bubbles during cystine stone fragmentation may lead to two clinical problems: First, hydrophobic, clustered bubbles may reduce image quality during RIRS and PNL and thus to prolonged operative time and decreased stone-free rate. Second, hydrogen sulfide gas carries a risk of inhaler toxicity for patients and healthcare professionals in the operating room. Cystine stones are harder than most of stones and more challenging to manage with endourological procedures. Previous studies stated that cystine stone reduces the stone-free rate and increases the need for multiple tracts in PNL[ 20 , 21 ]. Tendency to multiple calyceal localization, hard chemical structure, increased recurrence rate are the main reasons that complicate the management. In addition, hydrophobic bubbles formed during Ho:YAG laser fragmentation may hide stone fragments. Inability to detect stone fragments surrounded by bubbles may reduce the stone-free rate. In addition, lithotripsy of detected fragments may prolong operative time due to reduced image quality. Hence the bubbles emerging during Ho:YAG laser fragmentation of cystine stone may challenge the surgical intervention. Moreover, these bubbles bear the risk of toxicity as they contain H 2 S. H 2 S is now recognized as an endogenous signal “gasotransmitter” in mammals. It can be produced endogenously in mammalian cells or synthesized from bacteria in the intestinal microbiota [ 22 ]. It affects the regulation of oxidative stress, glucose and lipid metabolism and mitochondrial functions at cellular level. Therefore, it provides the regulation of immune system cells and hepatic cell functions and has a neuroprotectant and neuromodulator role in the nervous system [ 22 – 24 ]. However, H 2 S is toxic to humans when physiological levels are exceeded. Hydrogen sulfide is the second most common cause of fatal gas inhalation exposures, after carbon monoxide. Hydrogen sulfide toxicity is produced in conditions where sulfur containing compounds decompose under reducing conditions by chemical or microbial action (For example, oil and natural gas, sewage, animal waste, and geological resources) [ 25 ]. As the present study has established, hydrogen sulfide can also emerge during Ho:YAG laser lithotripsy of the sulfur containing cystine stone. Hydrogen sulfide gas can exert different toxic effects at various concentrations. Whereas low concentration levels may cause headache, fatigue, nausea, conjunctivitis, high level exposure may cause fatal clinics such as, pulmonary edema, cardiac arrhythmia, and immediate collapse [ 26 ]. The effectiveness of the treatments to be applied in case of exposure is not satisfactory. Although hyperbaric oxygen therapy, nitrate therapy and various pharmacological treatments are applied, the results are not satisfactory in case of severe toxicity [ 27 ]. Therefore, it becomes even more important to be aware of toxic hazard risk to prevent toxicity. Acute and chronic hydrogen sulfide toxicity hazard risk awareness should be raised among urologists, and protective measures should be discussed further for the patient and operating room personnel. There are some precautions against the potential effects of bubbles emerging during Ho:YAG laser fragmentation of cystine stone. As the mechanically affecting lithotripters (ultrasonic, pneumatic) will not cause chemical decomposition, these could be used in cystine stone surgery [ 28 ]. Therefore, PNL with mechanical lithotripters could be preferred in large volume cystine stones. In endourological procedures where the Ho:YAG laser is used, some surgical instruments can be used to eliminate the bubbles. Flexible-tip suction ureteral access sheaths in RIRS and suction devices in PNL are used safely during surgery and increase stone-free rates [ 29 , 30 ]. These relatively new surgical instruments can be used for bubble suction. Thus, the potential side effects of hydrogen sulphate containing bubbles can be avoided. Perhaps most important to urologists is the awareness of possible hydrogen sulfide toxicity in cystine stone patients undergoing Ho:YAG laser lithotripsy. The inherent limitations of the present study are the following: It is a qualitative study about chemical content analysis. Quantitative measurements such as mass-loss measurement could have contributed to the study. Different laser lithotripters such as thulium fiber laser, which are used almost daily, are not used in the present study. Despite all these inherent limitations, the significance of the present study is that it is the first evidence of hydrogen sulfide gas production and highlighting its potential clinical importance during Ho:YAG laser fragmentation of cystine stone. However, the data obtained in the present study is to be supported with further in vivo studies that include quantitative measurements. CONCLUSIONS The evidence obtained that hydrogen sulfide emerges in the gaseous environment during Ho:YAG laser fragmentation of cystine stone requires caution against the risk of in vivo production. Clinical studies investigating toxicity in cystine stone patients may highlight the importance of this under-researched condition. Declarations Acknowledgments: The authors thank Selçuk University Advanced Technology Research and Application Center for helping with exprimental organization for the study. Authorship contributions statement : Writing – original draft (lead); Conceptualization- Formal analysis- Visualization -Resources: [Muzaffer Tansel Kılınç]; Resources- Data curation- Methodology: [Mehmet Serkan Özkent]; Supervision (lead); Conceptualization- Formal analysis- Visualization -Resources- Review and editing: [Yunus Emre Göger] Competing interests: The authors declare that they have no competing interests exist. Funding: No funding was received for conducting this study. Employment: None. Financial Interests: The authors declare they have no financial interests. Non- Financial Interests: None. References Servais, A., et al., Cystinuria: clinical practice recommendation , in Kidney Int . 2021. p. 48-58. Moore, S.L., B.K. Somani, and P. 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Ganesamoni, R., et al., Prospective randomized controlled trial comparing laser lithotripsy with pneumatic lithotripsy in miniperc for renal calculi. J Endourol, 2013. 27 (12): p. 1444-9. Gauhar, V., et al., A Feasibility Study on Clinical Utility, Efficacy and Limitations of 2 Types of Flexible and Navigable Suction Ureteral Access Sheaths in Retrograde Intrarenal Surgery for Renal Stones. Urology, 2023. De Stefano, V., et al., Suction in Percutaneous Nephrolithotripsy: Evolution, Development, and Outcomes from Experimental and Clinical studies. Results from a Systematic Review. European Urology Focus, 2023. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 08 Jan, 2024 Read the published version in Urolithiasis → Version 1 posted Editorial decision: Revision requested 15 Nov, 2023 Reviews received at journal 06 Nov, 2023 Reviewers agreed at journal 29 Oct, 2023 Reviewers invited by journal 29 Oct, 2023 Editor assigned by journal 25 Oct, 2023 Submission checks completed at journal 25 Oct, 2023 First submitted to journal 24 Oct, 2023 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3487502","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":242931234,"identity":"f6c6f8ad-041d-4ce6-b062-f589e53ed39a","order_by":0,"name":"Muzaffer Tansel 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1","display":"","copyAsset":false,"role":"figure","size":110256,"visible":true,"origin":"","legend":"\u003cp\u003eIn vitro cystine stone fragmentation with Holmium:YAG laser experimental setup (a: before fragmentation, b: gas production after fragmentation)\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3487502/v1/745bbf361ef299b9054ac8d6.jpg"},{"id":45388661,"identity":"dad13483-87c1-4b8c-8ea5-a5bcfa3d0400","added_by":"auto","created_at":"2023-10-29 01:56:44","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":125452,"visible":true,"origin":"","legend":"\u003cp\u003eChromatography curves (a: scanning analysis curves, b: the selected ion monitoring (SIM) analysis curves)\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3487502/v1/9454cd6fd65eab9f06aecacd.jpg"},{"id":45389006,"identity":"4bb65ab7-f4d6-4eed-97f9-9cd69db2b61a","added_by":"auto","created_at":"2023-10-29 02:04:44","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":181562,"visible":true,"origin":"","legend":"\u003cp\u003eScanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) image of dried cystine stone experimental setup fragments\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3487502/v1/94dac13a3a3582599d80b71f.jpg"},{"id":45388664,"identity":"30ae86c3-6ff4-4837-a2f3-30ab8f7a1190","added_by":"auto","created_at":"2023-10-29 01:56:45","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":86829,"visible":true,"origin":"","legend":"\u003cp\u003eThe bubbles formed during Holmium:YAG laser lithotripsy of cystine stone in kidney\u003c/p\u003e","description":"","filename":"Figure4..jpg","url":"https://assets-eu.researchsquare.com/files/rs-3487502/v1/848dbe589f2e5714fcced6a7.jpg"},{"id":49628562,"identity":"ca51c52b-c03d-407f-8562-9a972632211b","added_by":"auto","created_at":"2024-01-15 15:07:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":559013,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3487502/v1/1eb5edac-427d-4247-bfbf-924de8151bec.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Chemical, Chromatographic and Electron Microscopic Analysis of the Bubbles Emerging During Holmium:YAG Laser Lithotripsy of Cystine Stone","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eCystinuria is an autosomal recessive disease characterized by defective reabsorption of cystine and dibasic amino acids in the renal proximal tubule. The high concentration of cystine in the urine and its low solubility at normal urinary pH may result in cystine stone formation. Cystine stones constitute 1\u0026ndash;3% of urinary system stones in adults and 6\u0026ndash;8% in children [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Although the frequency of cystine stones is low, they constitute an important health problem due to high rates of recurrence and surgical interventions [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Patients have an increased risk of kidney damage due to recurrent surgical interventions and episodes of obstruction. Therefore, management and treatment of cystine stones is of vital importance especially in children.\u003c/p\u003e \u003cp\u003eRetrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PNL) are often used in the endourological treatment of renal cystine stones, and the holmium: yttrium-aluminium-garnet (Ho:YAG) laser is extensively used lithotripter device [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Adjustable power settings and high absorption peak in water at a wavelength of 2140 nm make the Ho:YAG laser is the most employed, safe, and effective lithotripsy system in urolithiasis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe Ho:YAG laser causes stone fragmentation by photoacoustic and photothermal ablative mechanism [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The photoacoustic mechanism is based on the fragmentation of the stone by the shock wave produced during plasma expansion and bubble collapse with laser energy. In the photothermal ablative mechanism, the stone surface heats up to a thermal threshold with laser energy and fragmentation occurs. It has been proven in the study of Chan et al. that the dominant mechanism in stone fragmentation in the Ho:YAG laser is the photothermal ablative mechanism [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis mechanism may cause a change in the chemical structure of the stone and the formation of by-products. For example, Teichman et al. showed in their in vitro study that Ho:YAG laser lithotripsy of uric acid stones produced cyanide [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Cyanide inhibits oxidative phosphorylation and cellular ATP synthesis [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This can result in clinical manifestations ranging from dizziness, headache to lethal cardiac arrhythmia and hypoxia [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The emergence of potentially toxic by-products for the patient and operating room personnel raises additional safety issues in Ho:YAG laser lithotripsy.\u003c/p\u003e \u003cp\u003eSimilarly, chemical structure changes also occur in cystine stone during Ho:YAG laser lithotripsy [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In previous studies, it has been stated that free cysteine, cystine, and free sulfur were detected in the aqueous medium after in-vitro laser fragmentation of cystine stone [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In the clinical observation of most urologists, visible bubbles occur during the fragmentation of cystine stone with Ho:YAG laser. These bubbles appear as cloudy white, hydrophobic bubbles in the saline and recognized by most urologists for their specific \"rotten egg odor\". According to our best knowledge, currently there is not any study in the relevant literature about the chemical content of these bubbles and discussing their clinical importance.\u003c/p\u003e \u003cp\u003eThe primary aim of the present in vitro study is to analyze the chemical content of the bubbles occurring during the fragmentation of cystine stone with high-power and low-power Ho:YAG laser. The secondary aim of our study is to discuss their clinical importance.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eIn vitro cystine stone fragmentation, experimental setup and gas extraction:\u003c/h2\u003e \u003cp\u003eHuman renal calculi (calcium oxalate monohydrate (COM), cystine, and uric acid) were obtained from Necmettin Erbakan University Urology clinic. Stone analyzes were performed by X-ray diffraction analysis before the in vitro fragmentation. The calculi were placed into the sterile biochemistry tubes separately, full-filled with sterile 0.9% sodium chloride solution. Tube and luer lock connector are integrated to each other with airtight latex material. 270 micron Ho:YAG laser fiber was passed through the connector and placed in a way that it would contact the stone. The air tightness of each experimental setup was confirmed with a leak tester (Karl Storz, Tuttlingen, Germany). Then, a 5-cc injector was placed to the connector to obtain the bubbles after laser fragmentation (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e1\u003c/span\u003ea).\u003c/p\u003e \u003cp\u003eCOM, cystine, and uric acid calculi were fragmented with low-power and high-power Ho:YAG laser in separate experimental setups at room temperature, and it was observed whether the injector was filled with gas during this time. In order to avoid evaporation of the water in the sodium chloride solution, a rise in the temperature of more than 10\u0026deg;C during the fragmentation was prevented. Low-power Ho:YAG laser (Energy settings: 1 joule/pulse at 8 Hz, 30-Watts, Medilas H Solvo\u0026reg;, Dornier MedTech Europe GmbH, Wessling, Germany) and high-power Ho:YAG laser (Energy settings: 1 joule/pulse at 50 Hz, 150- Watts, MultiPulse HoPlus, Jena Surgical, Jena, Germany) were used for laser fragmentation.\u003c/p\u003e \u003cp\u003eAfter both low-power laser and high-power laser lithotripsy, a cloudy colored gas was obtained only fragmentation of cystine stone (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e1\u003c/span\u003eb).\u003c/p\u003e \u003cp\u003eAfter the gas was injected into the airtight screw top clear vials (Agilent Technologies, Santa Clara, Palo Alto, CA, USA) it was immediately taken to the gas chromatography laboratory. In addition, the fragments in the aqueous cystine calculi setup were dried and taken to the laboratory to be examined with scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction analysis.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eGas chromatography\u0026ndash;mass spectrometry (GC/MS) analysis:\u003c/h2\u003e \u003cp\u003eAn Agilent 7890B GC System (Santa Clara, Palo Alto, CA, USA) equipped with an Agilent Technologies GC Sampler 80 Autosampler and an Agilent J\u0026amp;W DB-WAX GC Column, 60 m, 0.25 mm, 0.25 \u0026micro;m was used. Moreover, headspace sampling was used for analysis. The following conditions were set for the oven: 35\u0026deg;C, maintain for 6 min; 35\u0026ndash;50\u0026deg;C at intervals of 2\u0026deg;C/min, hold for 5 min; 50\u0026ndash;80\u0026deg;C at intervals of 5\u0026deg;C/min, hold for 5 min. The temperature at the inlet was set to 240\u0026deg;C. With a 3.0 mL/min flow rate, 99.999% pure helium was used as the carrier gas for chromatographic analysis. An injection volume of 1 mL was analyzed in the split mode (10:1). The interface MS temperature was set to 230\u0026deg;C. The detection was performed with an Agilent 5977A MSD mass spectrometer (Santa Clara, Palo Alto, CA, USA), operating in the electron ionization mode (EI) at 70 eV. The selected ion monitoring (SIM) mode was used to acquire the Hydrogen sulfide (H\u003csub\u003e2\u003c/sub\u003eS) signal at m/z 34 and 32. The ion m/z 32 and 34 was also investigated during the simultaneous scan monitoring to guarantee H\u003csub\u003e2\u003c/sub\u003eS identification.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eScanning electron microscopy with energy dispersive X-ray spectroscopy (SEM\u0026ndash;EDX):\u003c/h2\u003e \u003cp\u003eDried fragments were directly mounted on specimen stubs via double sided adhesive discs, and then coated with gold in a Poleron SC7620 sputter coater for the SEM studies. Micrographs were taken with a Zeiss LS-10.\u003c/p\u003e \u003cp\u003eSEM\u0026ndash;EDX was carried out on a Zeiss LS-10 SEM operating at 15 kV with a probe current of 2500 pA to which a Bruker AXS detector EDX system had been interfaced.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eEthics and Consent to Participate:\u003c/h2\u003e \u003cp\u003eAll procedures performed in this study were conducted in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Necmettin Erbakan University Meram Faculty of Medicine Ethics Committee granted the consent, in line with the Helsinki declaration, before the onset of the study (No: 2021/3450).\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eNo gas production was observed after fragmentation in the COM and uric acid stone experimental setup. In the cystine stone experimental setup, gas output was observed after fragmentation with both low power and high power Ho:YAG laser, and analyzed separately. Qualitative content analysis was performed on both samples with GC-MS device.\u003c/p\u003e \u003cp\u003eIn the scanning analysis performed on the GC-MS device, peaks belonging to 7 components were observed. In the library scanning on these peaks, high quality content was detected in the 3rd and 7th peaks. It was determined that the 3rd peak belonged to H\u003csub\u003e2\u003c/sub\u003eS (Retention time 6.106 minutes, Quality 64%) and the 7th peak belonged to Thiophene (C\u003csub\u003e2\u003c/sub\u003eH\u003csub\u003e4\u003c/sub\u003eS, Retention time 19.886 minutes, Quality 95%, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). In addition, free sulfur was detected in the scan mode.\u003c/p\u003e \u003cp\u003eIn order to detect H\u003csub\u003e2\u003c/sub\u003eS, the SIM analysis performed after simultaneous scan monitoring, using 34 and 32 ions. In the SIM analysis, peaks belonging to four components were observed. In the library scan, high quality content was found to the 1st and 3rd peaks. Both peaks belonged to H\u003csub\u003e2\u003c/sub\u003eS (Retention time 5.59 and 5.96 minutes, Quality 83%, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e2\u003c/span\u003eb).\u003c/p\u003e \u003cp\u003eIn SEM-EDX mapping analysis, free cystine molecule containing 42.8% sulfur (S), 21% oxygen (O), 14.9% carbon (C), 21% nitrogen (N) atom was detected in the experimental environment (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eCystine molecule was detected in the X-ray diffraction analysis of the dried fragments.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe present in vitro study showed that free cystine, sulfur, thiophene, and hydrogen sulfide gas emerged during low-power and high-power Ho:YAG laser lithotripsy of cystine stones. The clinical significance is that Ho:YAG laser lithotripsy of cystine stone lead to the risk of in vivo hydrogen sulfide production which emerge as cloudy white, hydrophobic bubbles in the kidney during the fragmentation (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e4\u003c/span\u003e). These, hydrogen sulfide-containing gas bubbles may complicate the surgery and pose a potential risk of toxicity to the patient as well as to the personnel in the operating room.\u003c/p\u003e \u003cp\u003eLaser lithotripters have been utilized in urologic surgical interventions for about four decades. Q-switched Nd:YAG (neodymium-doped yttrium aluminum garnet) and pulsed dye laser are the first conventional lasers used in lithotripsy. These lasers cause the plasma expansion and bubble collapse in the aqueous working environment. The shock waves that occur during this plasma expansion and bubble collapse, cause fragmentation of the calculi surface via a mechanical effect [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. However, the most important limitation of conventional lasers was their low efficiency to fragmentation of hard calculi such as COM, cystine [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Currently, the Ho:YAG laser, which is effective in all stone types is the most commonly used laser lithotripter [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe main lithotripsy mechanism of the Ho:YAG laser, differing from conventional lasers, is its \u0026ldquo;Photothermal Ablative Mechanism\u0026rdquo; [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The Ho:YAG laser energy increases the temperature on the stone surface up to a critical threshold with the vapor channel until chemical breakdown. In other words, the shock wave of the bubbles formed by the laser energy does not play the main role in the fragmentation. Instead, the laser energy is absorbed by the calculus, resulting in a chemical decomposition with thermal energy [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The shock waves (photoacoustic mechanism) are thought to play a lesser role in stone fragmentation. Therefore, chemical structural changes may occur in stone during the Ho:YAG laser lithotripsy. Observation of the by-products derived from different calculi such as free sulfur and cysteine from cystine calculi, calcium carbonate from calcium oxalate monohydrate calculi, and cyanide from uric acid calculi support this thermo-chemical change [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe production of solid or liquid phase by-products in the working environment as a result of chemical decomposition during Ho:YAG laser fragmentation of cystine stone was previously determined [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, the production of gaseous by-products has not been sufficiently investigated. The accumulation of hydrogen sulfide containing hydrophobic gas bubbles during cystine stone fragmentation may lead to two clinical problems: First, hydrophobic, clustered bubbles may reduce image quality during RIRS and PNL and thus to prolonged operative time and decreased stone-free rate. Second, hydrogen sulfide gas carries a risk of inhaler toxicity for patients and healthcare professionals in the operating room.\u003c/p\u003e \u003cp\u003eCystine stones are harder than most of stones and more challenging to manage with endourological procedures. Previous studies stated that cystine stone reduces the stone-free rate and increases the need for multiple tracts in PNL[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Tendency to multiple calyceal localization, hard chemical structure, increased recurrence rate are the main reasons that complicate the management. In addition, hydrophobic bubbles formed during Ho:YAG laser fragmentation may hide stone fragments. Inability to detect stone fragments surrounded by bubbles may reduce the stone-free rate. In addition, lithotripsy of detected fragments may prolong operative time due to reduced image quality. Hence the bubbles emerging during Ho:YAG laser fragmentation of cystine stone may challenge the surgical intervention.\u003c/p\u003e \u003cp\u003eMoreover, these bubbles bear the risk of toxicity as they contain H\u003csub\u003e2\u003c/sub\u003eS. H\u003csub\u003e2\u003c/sub\u003eS is now recognized as an endogenous signal \u0026ldquo;gasotransmitter\u0026rdquo; in mammals. It can be produced endogenously in mammalian cells or synthesized from bacteria in the intestinal microbiota [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. It affects the regulation of oxidative stress, glucose and lipid metabolism and mitochondrial functions at cellular level. Therefore, it provides the regulation of immune system cells and hepatic cell functions and has a neuroprotectant and neuromodulator role in the nervous system [\u003cspan additionalcitationids=\"CR23\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. However, H\u003csub\u003e2\u003c/sub\u003eS is toxic to humans when physiological levels are exceeded. Hydrogen sulfide is the second most common cause of fatal gas inhalation exposures, after carbon monoxide. Hydrogen sulfide toxicity is produced in conditions where sulfur containing compounds decompose under reducing conditions by chemical or microbial action (For example, oil and natural gas, sewage, animal waste, and geological resources) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. As the present study has established, hydrogen sulfide can also emerge during Ho:YAG laser lithotripsy of the sulfur containing cystine stone.\u003c/p\u003e \u003cp\u003eHydrogen sulfide gas can exert different toxic effects at various concentrations. Whereas low concentration levels may cause headache, fatigue, nausea, conjunctivitis, high level exposure may cause fatal clinics such as, pulmonary edema, cardiac arrhythmia, and immediate collapse [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The effectiveness of the treatments to be applied in case of exposure is not satisfactory. Although hyperbaric oxygen therapy, nitrate therapy and various pharmacological treatments are applied, the results are not satisfactory in case of severe toxicity [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTherefore, it becomes even more important to be aware of toxic hazard risk to prevent toxicity. Acute and chronic hydrogen sulfide toxicity hazard risk awareness should be raised among urologists, and protective measures should be discussed further for the patient and operating room personnel.\u003c/p\u003e \u003cp\u003eThere are some precautions against the potential effects of bubbles emerging during Ho:YAG laser fragmentation of cystine stone. As the mechanically affecting lithotripters (ultrasonic, pneumatic) will not cause chemical decomposition, these could be used in cystine stone surgery [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Therefore, PNL with mechanical lithotripters could be preferred in large volume cystine stones. In endourological procedures where the Ho:YAG laser is used, some surgical instruments can be used to eliminate the bubbles. Flexible-tip suction ureteral access sheaths in RIRS and suction devices in PNL are used safely during surgery and increase stone-free rates [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. These relatively new surgical instruments can be used for bubble suction. Thus, the potential side effects of hydrogen sulphate containing bubbles can be avoided. Perhaps most important to urologists is the awareness of possible hydrogen sulfide toxicity in cystine stone patients undergoing Ho:YAG laser lithotripsy.\u003c/p\u003e \u003cp\u003eThe inherent limitations of the present study are the following: It is a qualitative study about chemical content analysis. Quantitative measurements such as mass-loss measurement could have contributed to the study. Different laser lithotripters such as thulium fiber laser, which are used almost daily, are not used in the present study. Despite all these inherent limitations, the significance of the present study is that it is the first evidence of hydrogen sulfide gas production and highlighting its potential clinical importance during Ho:YAG laser fragmentation of cystine stone. However, the data obtained in the present study is to be supported with further in vivo studies that include quantitative measurements.\u003c/p\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eThe evidence obtained that hydrogen sulfide emerges in the gaseous environment during Ho:YAG laser fragmentation of cystine stone requires caution against the risk of in vivo production. Clinical studies investigating toxicity in cystine stone patients may highlight the importance of this under-researched condition.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u0026nbsp;\u003c/strong\u003eThe authors thank Sel\u0026ccedil;uk University Advanced Technology Research and Application Center for helping with exprimental organization for the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthorship contributions statement\u003c/strong\u003e: Writing \u0026ndash; original draft (lead); Conceptualization- Formal analysis- Visualization -Resources: [Muzaffer Tansel Kılın\u0026ccedil;]; Resources- Data curation- Methodology: [Mehmet Serkan \u0026Ouml;zkent]; \u0026nbsp;Supervision (lead); Conceptualization- Formal analysis- Visualization -Resources- Review and editing: [Yunus Emre G\u0026ouml;ger]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no competing interests exist.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eNo funding was received for conducting this study.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eEmployment:\u003c/strong\u003e\u003c/em\u003e None.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eFinancial Interests:\u003c/strong\u003e\u003c/em\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003eThe authors declare they have no financial interests.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eNon- Financial Interests:\u0026nbsp;\u003c/strong\u003e\u003c/em\u003e\u003cem\u003eNone.\u003c/em\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eServais, A., et al., \u003cem\u003eCystinuria: clinical practice recommendation\u003c/em\u003e, in \u003cem\u003eKidney Int\u003c/em\u003e. 2021. p. 48-58.\u003c/li\u003e\n\u003cli\u003eMoore, S.L., B.K. Somani, and P. Cook, \u003cem\u003eJourney of a cystinuric patient with a long-term follow-up from a medical stone clinic: necessity to be SaFER (stone and fragments entirely removed).\u003c/em\u003e Urolithiasis, 2019. \u003cstrong\u003e47\u003c/strong\u003e(2): p. 165-170.\u003c/li\u003e\n\u003cli\u003eBarreto, L., et al., \u003cem\u003eMedical and surgical interventions for the treatment of urinary stones in children\u003c/em\u003e, in \u003cem\u003eCochrane Database Syst Rev\u003c/em\u003e. 2018. p. Cd010784.\u003c/li\u003e\n\u003cli\u003eRuggera, L., et al., \u003cem\u003eRetrograde transureteral approach: a safe and efficient treatment for recurrent cystine renal stones.\u003c/em\u003e Urol Res, 2011. \u003cstrong\u003e39\u003c/strong\u003e(5): p. 411-5.\u003c/li\u003e\n\u003cli\u003ePierre, S. and G.M. 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Salath\u0026eacute;, \u003cem\u003eFragmentation process of current laser lithotriptors.\u003c/em\u003e Lasers Surg Med, 1995. \u003cstrong\u003e16\u003c/strong\u003e(2): p. 134-46.\u003c/li\u003e\n\u003cli\u003eThomas, S., et al., \u003cem\u003eThe pulsed dye laser versus the Q-switched Nd:YAG laser in laser-induced shock-wave lithotripsy.\u003c/em\u003e Lasers Surg Med, 1988. \u003cstrong\u003e8\u003c/strong\u003e(4): p. 363-70.\u003c/li\u003e\n\u003cli\u003eAdams, D.H., \u003cem\u003eHolmium:YAG laser and pulsed dye laser: a cost comparison.\u003c/em\u003e Lasers Surg Med, 1997. \u003cstrong\u003e21\u003c/strong\u003e(1): p. 29-31.\u003c/li\u003e\n\u003cli\u003eLeijte, J.A., J.R. Oddens, and T.M. Lock, \u003cem\u003eHolmium laser lithotripsy for ureteral calculi: predictive factors for complications and success.\u003c/em\u003e J Endourol, 2008. \u003cstrong\u003e22\u003c/strong\u003e(2): p. 257-60.\u003c/li\u003e\n\u003cli\u003eChan, K.F., et al., \u003cem\u003eA perspective on laser lithotripsy: the fragmentation processes.\u003c/em\u003e J Endourol, 2001. \u003cstrong\u003e15\u003c/strong\u003e(3): p. 257-73.\u003c/li\u003e\n\u003cli\u003eJacques, S.L., \u003cem\u003eLaser-tissue interactions. Photochemical, photothermal, and photomechanical.\u003c/em\u003e Surg Clin North Am, 1992. \u003cstrong\u003e72\u003c/strong\u003e(3): p. 531-58.\u003c/li\u003e\n\u003cli\u003eSchafer, S.A., et al., \u003cem\u003eMechanisms of biliary stone fragmentation using the Ho:YAG laser.\u003c/em\u003e IEEE Trans Biomed Eng, 1994. \u003cstrong\u003e41\u003c/strong\u003e(3): p. 276-83.\u003c/li\u003e\n\u003cli\u003eVassar, G.J., et al., \u003cem\u003eHolmium: YAG lithotripsy: photothermal mechanism.\u003c/em\u003e J Endourol, 1999. \u003cstrong\u003e13\u003c/strong\u003e(3): p. 181-90.\u003c/li\u003e\n\u003cli\u003eKaygısız, O., et al., \u003cem\u003eRenal stone composition does not affect the outcome of percutaneous nephrolithotomy in children.\u003c/em\u003e World J Urol, 2018. \u003cstrong\u003e36\u003c/strong\u003e(11): p. 1863-1869.\u003c/li\u003e\n\u003cli\u003eTiryaki, T., M.N. 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Gautam, \u003cem\u003eHydrogen sulfide, nitric oxide, and neurodegenerative disorders.\u003c/em\u003e Transl Neurodegener, 2018. \u003cstrong\u003e7\u003c/strong\u003e: p. 3.\u003c/li\u003e\n\u003cli\u003eWu, D.D., et al., \u003cem\u003eHydrogen Sulfide as a Novel Regulatory Factor in Liver Health and Disease.\u003c/em\u003e Oxid Med Cell Longev, 2019. \u003cstrong\u003e2019\u003c/strong\u003e: p. 3831713.\u003c/li\u003e\n\u003cli\u003eGuidotti, T.L., \u003cem\u003eHydrogen sulfide intoxication.\u003c/em\u003e Handb Clin Neurol, 2015. \u003cstrong\u003e131\u003c/strong\u003e: p. 111-33.\u003c/li\u003e\n\u003cli\u003eGuidotti, T.L., \u003cem\u003eHydrogen sulfide: advances in understanding human toxicity.\u003c/em\u003e Int J Toxicol, 2010. \u003cstrong\u003e29\u003c/strong\u003e(6): p. 569-81.\u003c/li\u003e\n\u003cli\u003eNg, P.C., et al., \u003cem\u003eHydrogen Sulfide Toxicity: Mechanism of Action, Clinical Presentation, and Countermeasure Development.\u003c/em\u003e J Med Toxicol, 2019. \u003cstrong\u003e15\u003c/strong\u003e(4): p. 287-294.\u003c/li\u003e\n\u003cli\u003eGanesamoni, R., et al., \u003cem\u003eProspective randomized controlled trial comparing laser lithotripsy with pneumatic lithotripsy in miniperc for renal calculi.\u003c/em\u003e J Endourol, 2013. \u003cstrong\u003e27\u003c/strong\u003e(12): p. 1444-9.\u003c/li\u003e\n\u003cli\u003eGauhar, V., et al., \u003cem\u003eA Feasibility Study on Clinical Utility, Efficacy and Limitations of 2 Types of Flexible and Navigable Suction Ureteral Access Sheaths in Retrograde Intrarenal Surgery for Renal Stones.\u003c/em\u003e Urology, 2023.\u003c/li\u003e\n\u003cli\u003eDe Stefano, V., et al., \u003cem\u003eSuction in Percutaneous Nephrolithotripsy: Evolution, Development, and Outcomes from Experimental and Clinical studies. Results from a Systematic Review.\u003c/em\u003e European Urology Focus, 2023.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"urolithiasis","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ures","sideBox":"Learn more about [Urolithiasis](http://link.springer.com/journal/240)","snPcode":"240","submissionUrl":"https://submission.nature.com/new-submission/240/3","title":"Urolithiasis","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Chemical Decomposition, Chromatographic Analysis, Cystine Stone, Holmium:YAG Laser, Photothermal Ablative Mechanism, Toxicity","lastPublishedDoi":"10.21203/rs.3.rs-3487502/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3487502/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe primary aim of the present in vitro study is to analyze the chemical content of the bubbles occurring during the fragmentation of cystine stone with high-power and low-power Ho:YAG laser. The secondary aim of our study is to discuss their clinical importance. Human renal calculi (calcium oxalate monohydrate (COM), cystine, and uric acid) were fragmanted with low-power and high-power Ho:YAG laser in separate experimental setups at room temprature, and it was observed whether the gas production during this time. After laser lithotripsy, a cloudy colored gas was obtained only fragmentation of cystine stone. Qualitative gas content analysed performed with Gas chromatography\u0026ndash;mass spectrometry device. In addition, the fragments in the aqueous cystine calculi setup were dried and taken to the laboratory to be examined with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction analysis. No gas production was observed after fragmentation in the COM and uric acid stone. Free cystine, sulfur, thiophene, and hydrogen sulfide gas were produced by low-power and high-power Ho:YAG laser lithotripsy of cystine stone. In SEM-EDX mapping analysis, free cystine molecule containing 42.8% sulfur (S), 21% oxygen (O), 14.9% carbon (C), 21% nitrogen (N) atom was detected in the cystine stone experimental setup. The evidence obtained that hydrogen sulfide emerges in the gaseous environment during Ho:YAG laser fragmentation of cystine stone requires caution against the risk of in vivo production and toxicity.\u003c/p\u003e","manuscriptTitle":"Chemical, Chromatographic and Electron Microscopic Analysis of the Bubbles Emerging During Holmium:YAG Laser Lithotripsy of Cystine Stone","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-10-29 01:56:40","doi":"10.21203/rs.3.rs-3487502/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2023-11-16T04:28:41+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-11-06T10:29:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"b1731a5e-b540-44f2-9bf1-ab594c4e4965","date":"2023-10-29T15:07:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-10-29T15:02:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-10-26T01:24:01+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2023-10-26T01:24:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"Urolithiasis","date":"2023-10-24T20:25:38+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"urolithiasis","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ures","sideBox":"Learn more about [Urolithiasis](http://link.springer.com/journal/240)","snPcode":"240","submissionUrl":"https://submission.nature.com/new-submission/240/3","title":"Urolithiasis","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"6e963871-00e8-4f12-9b0c-fde51c1f087b","owner":[],"postedDate":"October 29th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-01-15T15:03:44+00:00","versionOfRecord":{"articleIdentity":"rs-3487502","link":"https://doi.org/10.1007/s00240-023-01517-4","journal":{"identity":"urolithiasis","isVorOnly":false,"title":"Urolithiasis"},"publishedOn":"2024-01-08 15:01:13","publishedOnDateReadable":"January 8th, 2024"},"versionCreatedAt":"2023-10-29 01:56:40","video":"","vorDoi":"10.1007/s00240-023-01517-4","vorDoiUrl":"https://doi.org/10.1007/s00240-023-01517-4","workflowStages":[]},"version":"v1","identity":"rs-3487502","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3487502","identity":"rs-3487502","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}