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INTRODUCTION: This article attempts to provide a comprehensive review of the learning objectives and importance of the supine percutaneous nephrolithotomy (PCNL) technique. MATERIAL METHOD: We retrospectively reviewed the cases of Supine PCNL between January 2018 and January 2024. We divided the groups into 3: residents between 2 and 3 years (Group 1), residents between 4 and 5 years (Group 2), and endourologist (Group 3). The 2-3-year resident started to perform PCNL for the first time, while the 4-5-year resident started to perform Supine PCNL for the first time while previously performing prone PCNL. RESULTS: Access, fluoroscopy, and operation time were higher in Group 1, shorter in Group 2, and shortest in Group 3 (p < 0.001). Postoperative length of stay and the need for additional treatment were found to be shorter (p < 0.001), and the stone-free rate (SFR) increased (p < 0.001) from Group 1 to Group 3. The highest complication rates were observed in Group 1 (p = 0.002). SFR rate increased as the number of cases increased in Group 1 patients. Success was stable after 46-60 cases in terms of SFR. In Group 2, the SFR rate was stable after 31-45. CASES: The most complications were observed in Group 1 and the least in Group 3. CONCLUSION: In 2-3-year residents, access time and fluoroscopy time decrease with experience. In 4-5-year residents, due to their expertise in prone PCNL, the operation time and fluoroscopy time decrease with the number of cases performed. SFR is higher after 46-60 cases for 2-3-year residents and 31-45 cases for 4-5-year residents.

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PURPOSE: To compare the image quality of magnetic resonance cholangiopancreatography (MRCP) in the supine position and prone position under the conditions of the same equipment, the same sequence (3D Navigator Triggered Sampling Perfection with Application-Optimized Contrast Using Different Flip-angle Evolutions, 3D-NT-SPACE) and the same patient, and to explore the clinical application value of prone position in MRCP examination to suppress respiratory motion artifacts. METHODS: 53 participants who underwent MRCP in our hospital from April 2020 to August 2022 were prospectively collected. The 3D-NT-SPACE sequence was used in these patients. The visibility of the common bile duct, common hepatic duct, main pancreatic duct, and first- and second- and third-level branches of the intrahepatic bile duct and the comfort of the participants in two positions were subjective-evaluated. The Signal-to-noise ratio (SNR) and contrast-to-noise ratio were objective-evaluated. Statistical analysis was performed using Shapiro-Wilk, Levene's, Mann Whitney U test, Pearson chi-square test, and one-sample chi-square test. RESULTS: 53 patients (51.92 years ± 2.02, 20 men) were evaluated. There were significant differences in the second- and third-level branches visibility score, the main pancreatic duct visibility score, the image quality score of the pancreaticobiliary tree, the blur and motion artifact score, the total image quality score, and SNR between the two positions (p < 0.05). CONCLUSIONS: The overall image quality of the prone position was better than that of the supine position. The prone position is a useful complement to the supine position.

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Background and Objective: Percutaneous Nephrolithotomy (PCNL) is recommended for large Kidney Stones. It is mostly done in prone position. However, PCNL in Supine position is another safe option. Only few centers in country are doing it and so it is challenging task to adopt supine PCNL approach in an institution initially. In this study our purpose was to assess initial experience of Supine PCNL in our center. Methods: It is a preliminary retrospective study of our first fifty-one supine PCNL procedures, performed by a single Surgeon, over Twelve months period, from April 2021 to April 2022. We managed a retrospective review of patients' records. Analysis was completed by utilizing SPSS version 20. Implementation of Mean along with standard deviation values was utilized for continuous variables. While frequency/percentages represented categorical factors. Results: Patients mean age was 39 years, comprising of 62.74% male and 37.25% female patients. Thirty patients had their stones treated on the left side. Mean Stone burden was 3.2 cm. Most of the stones were GUYs score one and two (complexity wise). The mean procedure time 147minutes. Mean hospital stay of 2.17 days was observed in this study. Forty patients were stone free. Only seven patients (14%) had level I-II complications (Clavien-Dindo classification). Conclusion: Supine PCNL can be adopted safely in an institute if careful selection of patients is done before surgery. In our center it had acceptable success rates and few complications.

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Background: In recent years, diaphragm ultrasound (DUS) has been used to identify diaphragm dysfunction in the intensive care unit (ICU). However, there are few studies on DUS parameters to evaluate function, normal ranges, and influencing factors in population. The aim of this study is to provide a methodological reference for clinical evaluation of diaphragm function by measuring different DUS parameters in a healthy population. Methods: A descriptive study was conducted 212 (105 males, 107 females) subjects with normal spirometry underwent ultrasound imaging in this study. The diaphragm contraction and motion related parameters and shear wave velocity (SWV) were measured in the supine position. The effects of gender, age, body mass index (BMI) and lifestyle on diaphragm ultrasound parameters were analyzed. Results: The diaphragm thickness at end-expiration (DT-exp) was 0.14 ±0.05 cm, the diaphragm thickness at end- inspiration (DT-insp) was 0.29±0.10 cm, with thickening fraction (TF) was 1.11±0.54. The diaphragm excursion (DE) was 1.68±0.37cm and diaphragm velocity was 1.45±0.41 cm/s during calm breathing. During deep breathing, the DE was 5.06±1.40cm and diaphragm velocity was 3.20±1.18 cm/s. The Diaphragm shear modulus-longitudinal view were Mean16.72±4.07kPa, Max25.04±5.58kPa, Min11.06±3.88kPa, SD2.56±0.98. The results of diaphragmatic measurement showed that the DT of males was significantly greater than that of females (P< 0.05), but there was no significant difference in TF. The DT-insp (r=0.155, P= 0.024) and the DT-exp (r=0.252, P=0.000) were positively correlated with age, and the DE during calm breathing was negatively correlated with age (r=-0.218, P= 0.001) and BMI (r=-00.280, P= 0.000). The DE (R=0.371, P=0.000) and velocity (R=0.368, P=0.000) during deep breathing were correlated with lifestyle. Conclusion: Our study provides normal reference values of the diaphragm and evaluates the influence of gender, age, body mass index and lifestyle on diaphragmatic morphology.

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Little is known about the physiological and biomechanical factors that determine individual preferences in lying posture during sleep. This study investigated relationships between position preference and position-specific arousals, awakenings, limb movements and limb movement arousals to explore the mechanisms by which biomechanical factors influence position preference. Forty-one mature-aged adults underwent 2 nights of at-home polysomnography ~2 weeks apart, on a standardised firm foam mattress, measuring nocturnal sleep architecture and position. The lateral supine ratio and restlessness indices specific to lateral and supine positions including limb movement index, limb movement arousal index, arousal index, wake index, respiratory arousal index and apnea-hypopnea index were calculated and analysed via linear mixed-effects regression. In the supine position, all restlessness indices were significantly increased compared with the lateral position, including a 379% increase in respiratory arousals (ß = 7.0, p < 0.001), 108% increase in arousal index (ß = 10.3, p < 0.001) and 107% increase in wake index (ß = 2.5, p < 0.001). Wake index in the supine position increased significantly with more lateral sleep (ß = 1.9, p = 0.0013), and significant correlation between lateral supine ratio polysomnography 1 and lateral supine ratio polysomnography 2 (ß = 0.95, p < 0.001) indicated strong consistency in sleep preference. Overall, the findings suggest that some individuals have low tolerance to supine posture, represented by a comparatively high wake index in the supine position, and that these individuals compensate by sleeping a greater proportion in the lateral position.

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In this study, intraocular pressure (IOP) was measured in sitting, supine, prone, and standing (ST) positions and again five minutes after standing (ST-5) utilizing a Tono-Pen AVIA in 124 eyes of 62 healthy subjects with ages ranging from 21 to 59 years (mean 30 ± 10 years). In each subject, the average IOP of both eyes was used for the statistical evaluation. The mean IOP difference between the ST and sitting positions was -0.13 ± 1.63 mmHg (p = 0.548); between ST-5 and sitting, it was 0.53 ± 1.24 mmHg (p = 0.001); between supine and sitting, it was 1.30 ± 1.48 mmHg (p < 0.001); between ST and supine, it was -1.43 ± 1.74 mmHg (p < 0.001); between ST-5 and supine, it was -0.77 ± 1.59 mmHg (p < 0.001); between prone and supine, it was 2.24 ± 1.92 mmHg (p < 0.001); between ST and ST-5, it was -0.67 ± 1.84 mmHg (range: -7.5 to 5 mmHg) (p = 0.007); between prone and ST, it was 3.46 ± 2.01 mmHg (p < 0.001); between ST-5 and prone, it was -2.46 ± 1.67 mmHg (p < 0.001); and between sitting and prone, it was -3.22 ± 1.56 mmHg (p < 0.001). The results show a significant IOP increase in the ST-5 position, suggesting that such measurements need to be performed in an attempt to explain the progression of glaucoma in apparently normal-tension patients.

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Background and Objectives: Percutaneous nephrolithotomy (PCNL) is a current treatment method with high success rates and low complication rates in treating large kidney stones. It can be conducted in different positions, especially supine and prone positions. PCNL in the supine position is becoming increasingly common due to its advantages, such as simultaneous retrograde intervention and better anesthesia management. This study aimed to assess how the choice of position impacts the PCNL learning curve. Materials and Methods: The results of the first 50 consecutive PCNL cases performed by two separate chief residents as primary surgeons in supine and prone positions in a reference center for stone treatment between August 2021 and January 2023 were evaluated. The two groups' demographic and clinical data, stone-free rates, operation times, and fluoroscopy times were compared. Results: While the mean operation time was 94.6 ± 9.8 min in the supine PCNL group, it was 129.9 ± 20.3 min in the prone PCNL group (p < 0.001). Median fluoroscopy times in the supine PCNL and prone PCNL groups were 31 (10-89) seconds and 48 (23-156) seconds, respectively (p = 0.001). During the operation, the plateau was reached after the 10th case in the supine PCNL group, while it was reached after the 40th case in the prone PCNL group. Conclusions: For surgeons who are novices in performing PCNL, supine PCNL may offer both better results and a faster learning curve. Prospective and randomized studies can provide more robust conclusions on this subject.

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BACKGROUND: Positional preferences, asymmetry of body position and movements potentially indicate abnormal clinical conditions in infants. However, a lack of standardized nomenclature hinders accurate assessment and documentation of these preferences over time. Video tools offer a safe and reproducible method to analyze and describe infant movement patterns, aiding in physiotherapy management and goal planning. The study aimed to develop an objective classification system for infant movement patterns with particular emphasis on the specific distribution of muscle tension, using methods of computer analysis of video recordings to enhance accuracy and reproducibility in assessments. METHODS: The study involved the recording of videos of 51 infants between 6 and 15 weeks of age, born at term, with an Apgar score of at least 8 points. Based on observations of a recording of infant spontaneous movements in the supine position, experts identified postural-motor patterns: symmetry and typical asymmetry linked to the asymmetrical tonic neck reflex. Deviations from the typical postural-motor system were indicated, and subcategories of atypical patterns were distinguished. A computer-based inference system was developed to automatically classify individual patterns. RESULTS: The following division of motor patterns was used: (1) normal patterns, including (a) typical (symmetrical, asymmetrical: variants 1 and 2); and (b) atypical (variants: 1 to 4), (2) positional preference, and (3) abnormal patterns. The proposed automatic classification method achieved an expert decision mapping accuracy of 84%. For atypical patterns, the high reproducibility of the system's results was confirmed. Lower reproducibility, not exceeding 70%, was achieved with typical patterns. CONCLUSIONS: Based on the observation of infant spontaneous movements, it is possible to identify movement patterns divided into typical and atypical patterns. Computer-based analysis of infant movement patterns makes it possible to objectify and satisfactorily reproduce diagnostic decisions.

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OBJECTIVES: To evaluate how the prone position influences mechanical power (MP) during elective surgical procedures. METHODS: In this prospective study carried out at Karadeniz Eregli Government Hospital, Zonguldak, Turkey, from January 2024 to February 2024, 76 patients under general anesthesia were evaluated at different time points during the surgical procedure. Hemodynamic, laboratory, and mechanical ventilation data were also recorded. RESULTS: The MP increased in the prone position at the beginning of surgery. Transitioning to the supine position at the end of surgery led to a decrease in MP. At the end of surgery, the mean MP in supine and prone positions was found to be higher compared to those measured in the first hour of surgery. Mechanical power and body mass index (BMI) exhibited a significant positive correlation. CONCLUSION: Position changes influence MP. Returning to the prone position increases MP. An increase in BMI is associated with an increase in MP.ANZCTR Reg. No.: ACTRN12623001281684.

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Sinus of Valsalva aneurysm (SoVA) is a rare disease with less than 1% prevalence in the population. Most cases are asymptomatic, however, significant clinical manifestations are possible due to fistula formation and sudden rupture resulting in cardiac shunt. Eventually it may develop into progressive heart failure with high morbidity. We report the case of a 33 year old female patient who presented with shortness of breath, ascites, and recurring hospitalisation. The cardiac examination revealed sinus tachycardia along with loud and continuous murmurs on the left parasternal border. Several standard diagnostic procedures could not be performed due to malignant arrhythmia in supine position. Echocardiography examination revealed SoV rupture with a gerbode defect, which was the underlying cause of severe retractable heart failure.

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Background: Double-lumen endotracheal tubes (DLT) are essential for one-lung ventilation during thoracic surgery. Bronchoscopy is crucial for correct placement of a DLT to avoid complications such as hypoxemia. This study evaluated the effectiveness of the triple-cuffed DLT (tcDLT) in the supine and lateral positions for correct placement without bronchoscopic guidance. Methods: This prospective observational study included 167 patients scheduled for elective thoracic surgery requiring one-lung ventilation. The incidence of successful placement of left-sided tcDLTs was compared between the supine and lateral decubitus positions under bronchoscopic surveillance. Successful tcDLT placement was defined as the placement of the proximal end of the bronchial cuff within 5 mm of the carina. Results: Among 153 patients who completed the study, the successful tcDLT placement rate in the lateral position (70.6%) was significantly higher than that in the supine position (50.3%). The rate of difference was 20.3% (95% confidence interval [CI], 10.6-29.9%). The extended successful placement rate, including slightly deeper placements, showed no significant differences between the positions (88.9%; 95% CI, 83.9‒93.9% in supine, 86.3%; 95% CI, 80.8‒91.7% in lateral). Conclusions: tcDLT facilitates correct tube placement in both the supine and lateral positions, with a higher lateral success rate. This finding supports the idea that tcDLTs offer a reliable alternative for lung separation when bronchoscopy is not feasible.

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Objective: Intraoperative mechanical ventilation practices can lead to ventilator-induced lung injury (VILI) and postoperative pulmonary complications in healthy lungs. Mechanical power (MP) has been developed as a new concept in reducing the risk of postoperative pulmonary complications as it considers all respiratory mechanics that cause VILI. The most commonly used intraoperative modes are volume control ventilation (VCV) and pressure control ventilation (PCV). In this study, VCV and PCV modes were compared in terms of respiratory mechanics in patients operated in the supine and prone positions. Methods: The patients were divided into 4 groups (80 patients), volume control supine and prone, pressure control supine and prone with 20 patients each. MP, respiratory rate, positive end-expiratory pressure, tidal volume, peak pressure, plato pressure, driving pressure, inspiratory time, height, age, gender, body mass index, and predictive body weight data of the patients included in the groups have been obtained from "electronic data pool" with Structured Query Language queries. Results: The supine and prone MP values of the VCV group were statistically significantly lower than the PCV group (P values were 0.010 and 0.001, respectively). Conclusion: Supine and prone MP values of the VCV group were calculated significantly lower than the PCV group. Intraoperative PCV may be considered disadvantageous regarding the risk of VILI in the supine and prone positions.

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OBJECTIVES: The supine sleep position and the rapid eye movement (REM) stage are widely recognized to exacerbate the severity of obstructive sleep apnea (OSA). Position-dependent OSA is generally characterized by an apnea-hypopnea index (AHI) that is at least twice as high in the supine position compared to other sleep positions. However, this condition can be misdiagnosed if a particular sleep stage-REM or non-REM (NREM)-predominates in a specific position. We explored the impact of the sleep stage on positional dependency in OSA. METHODS: Polysomnographic data were retrospectively analyzed from 111 patients with OSA aged 18 years or older, all of whom had an AHI exceeding five events per hour and slept in both supine and non-supine positions for at least 5% of the total sleep time. The overall ratio of non-supine AHI to supine AHI (NS/S-AHI ratio) was compared between total, REM, and NREM sleep. Additionally, a weighted NS/S-AHI ratio, reflecting the proportion of time spent in each sleep stage, was calculated and compared to the original ratio. RESULTS: The mean NS/S-AHI ratio was consistent between the entire sleep period and the specific sleep stages. However, the NS/S-AHI ratios for individual patients displayed poor agreement between total sleep and the specific stages. Additionally, the weighted NS/S-AHI ratio displayed poor agreement with the original NS/S-AHI ratio, primarily due to discrepancies in patients with mild to moderate OSA. CONCLUSION: The weighted NS/S-AHI ratio may help precisely assess positional dependency.

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Technique modifications that aim to improve ergonomics of the surgical procedure without repositioning the upper tract urothelial carcinoma patients remain a challenge to urologists. We offer a novel technique to perform intraperitoneal laparoscopic single-site radical nephroureterectomy and pelvic lymph nodes dissection/retroperitoneal lymph nodes dissection in a supine position. Our novel technique is feasible and offers a significant improvement in operative efficiency, particularly in patients with locally advanced disease.

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PURPOSE: To compare the efficacy, safety and advantages of the total tubeless (TT) percutaneous nephrolithotomy (PCNL) and standard PCNL in the supine position. METHODS: This study was carried out at Izmir Tepecik Health Application and Research Center. A total of 87 patients were examined. Forty-three patients who underwent TT procedure were defined as Group 1, and 44 patients who underwent standard procedure with a nephrostomy tube were defined as Group 2. Two techniques were evaluated with demographic data and outcome parameters. Univariate regression analyses were performed in these data sets for the parameters that predicted the TT procedure. RESULTS: The demographic data of the groups and all characteristics of the stones were similar. When the results were examined, the stone-free rates detected by non-contrast computed tomography (CT) in the postoperative 1st month were similar between the groups. Complication rates and secondary intervention rates were similar. Operation and fluoroscopy times were shorter in group 1, which were not statistically significant. Postoperative hemoglobin decreased, and creatinine values were similar. In Group 1, mean postoperative visual analog scale (VAS) scores and the percentage of VAS reporting > 5 points for pain level measurement were lower and statistically significant. In the univariate analysis of the factors predicting the TT procedure, no significant results were found in any parameter. CONCLUSION: Performing TT PCNL in the supine position in selected patients reduces postoperative pain without affecting the complication rates as in prone PCNL. Our study is the first to compare TT and standard PCNL in supine position.

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OBJECTIVES: The relationships among positional obstructive sleep apnea (POSA), obstructive sleep apnea (OSA), and periodic limb movements during sleep (PLMS) remain unclear. We investigated these relationships with respect to the severity of OSA and explored the underlying mechanisms. METHODS: We retrospectively reviewed 6,140 eligible participants who underwent full-night diagnostic polysomnography at four clinical centers over a 5-year period, utilizing event-synchronized analysis. We evaluated the periodic limb movement index (PLMI) and the periodic limb movement with arousal index (PLMAI). The impacts of POSA on the PLMI, PLMAI, and PLMS were analyzed in relation to the severity of OSA. RESULTS: The mean PLMI, the mean PLMAI, and the prevalence of PLMS were significantly lower in participants with severe OSA compared to the mild and moderate OSA groups. The mean PLMI among those with mild OSA exceeded that of control participants. Furthermore, the mean PLMI (4.8±12.7 vs. 2.6±9.8 events/hr, P<0.001), the mean PLMAI (0.9±3.7 vs. 0.5±3.3 events/hr, P<0.001), and the prevalence of PLMS (11% vs. 5.3%, P<0.001) were higher in patients with POSA than in those with non-positional OSA. This PLMS finding was particularly pronounced among those with severe OSA (odds ratio [OR], 1.554; 95% confidence interval [CI], 1.065-2.267) and was less evident in the mild (OR, 0.559; 95% CI, 0.303-1.030) and moderate (OR, 1.822; 95% CI, 0.995-3.339) groups. CONCLUSION: Patients with POSA, especially those with severe OSA, exhibit a comparatively high prevalence of PLMS. In cases involving prominent PLMS, the diagnosis and treatment of POSA and OSA should be considered.

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Background The deep inferior epigastric perforator (DIEP) and latissimus dorsi (LD) flaps are two widely used autologous breast reconstructions. Despite studies on flap-volume changes, the time of the first measurement is not immediately after surgery. Therefore, this study aimed to investigate the change in volume over time from the immediate postoperative period using a three-dimensional (3D) scanner. Methods Patients who underwent breast reconstruction with a DIEP or LD flap between October 2019 and December 2020 at Showa University Koto Toyosu Hospital were included. The Kinect 3D scanner was used to measure the reconstructed and healthy breast volumes immediately after surgery and at 1, 3, 6, and 12 months. The control group was the healthy side, and the volumes obtained at each time point and ratios (to the immediate postoperative period) were calculated and analyzed using a linear mixed model. Results Of the 25 patients and 26 breasts examined, the postoperative increase in volume ratios was statistically significant in the DIEP flap group, except for the sixth month, but decreased significantly in the LD group. Compared with the control group, the volume ratio was significantly higher up to 3 months in the DIEP flap group and decreased significantly after 3 months in the LD flap group. Conclusions The volume of the LD flap continued to decrease immediately after surgery, whereas the volume of the DIEP flap increased by 10% up to 1M. Therefore, this increase in volume should be taken into consideration in studies where the initial measurements were not taken immediately after surgery.

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Upper limb surgeons frequently encounter complex cases involving the proximal humerus, elbow joint, and proximal forearm, both in trauma and elective practice. Given the diverse pathology in these areas, various surgical approaches have been described, each with its advantages, limitations, and specific patient positioning requirements. We describe an operative technique that modifies the use of an existing, commercially available, dynamic pneumatic limb positioner, the TRIMANO FORTIS® (Arthrex, Maquet GmbH), for open and arthroscopic procedures of the elbow, proximal forearm, midshaft, and distal humerus. This technique offers simplicity, reproducibility, and enhanced surgical efficiency.

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Objective: To evaluate the learning curve and the success rate of the biplanar (0-90°) puncture technique in the flank-free modified supine position in comparison to the monoplanar puncture technique. Methods: Randomized controlled study included 68 patients more than 18 years with renal stones more than 2 cm from August 2021 to August 2022 were randomly classified by closed envelope method into group A (34 patients) scheduled for monoplanar renal puncture technique in flank-free modified supine PCN. Meanwhile, group B (34 patients) was scheduled for the 0-90° simplified fluoroscopic puncture technique. Morbid obese patients and patients with contraindications for PNL were omitted from the study. Results: There was no significant difference between both groups regarding stone distribution and patients' demographic data. There was a significant difference between both groups regarding puncture attempts. In 88.2% of patients in group B (Biplanar group), the success of renal puncture occurred from the 1st puncture attempt while in 11.2% of patients in group A (monoplanar group). There was a statistically significant difference between both groups in fluoroscopy time and total operation time (p-value <0.001 & p-value: 0.001), respectively. The stone-free rate was 85.2% vs. 88.2% in both groups, respectively, without significant difference. In this study puncture, attempt trials and puncture time were used as indicators for the easiness and rapid educability of the biplanar (0-90°) fluoroscopic guided renal puncture technique. In the biplanar (0-90°) group after 24 cases, the learning curve had reached the plateau. Conclusion: Biplanar (0-90°) puncture technique in flank-free modified supine position allows an easy puncture technique with an easy learning curve without affecting the success rate or complication rate.

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Intracranial pressure is one of the determinants of sympathetic activities, and sleep bruxism is associated with increased sympathetic activities. This study aimed to investigate effects of the low Fowler's sleep position and methazolamide treatment on the occurrence of rhythmic masticatory muscle activities/sleep bruxism episodes in patients with sleep bruxism in a randomized controlled trial. Polysomnographic recordings were performed on the patients with sleep bruxism sleeping in the low Fowler's (15°-30°) or supine position (n = 11), and with methazolamide or placebo treatment (100 mg, 3-4 hr before bedtime, P.O., n = 9), and changes in sleep variables and heart rate variance during sleep in the low Fowler's position or with methazolamide treatment were determined. Sleep bruxism index, number of masseter muscle electromyographic bursts per hour of sleep, ratio of rhythmic masticatory muscle activities/sleep bruxism duration to the total sleep duration, index of total limb movements, index of limb movements with rhythmic masticatory muscle activities, and number of sleep bruxism clusters per hour of sleep in the low Fowler's position and after methazolamide intake were significantly smaller (p < 0.05-0.001) than those in the supine position and after placebo intake, respectively. The low-frequency heart rate variance powers during non-rapid eye movement sleep stage 2 (N2) in the low Fowler's position and with methazolamide treatment were significantly lower (p < 0.05) than those during sleep in the supine position and with placebo treatment, respectively. In conclusion, sleep in the low Fowler's position and methazolamide treatment were associated with significant decreases in the occurrence of rhythmic masticatory muscle activities/sleep bruxism episodes, which might be due to a reduction in intracranial pressure and sympathetic activities mainly during non-rapid eye movement sleep stage 2.