Synthetic Data Improve Survival Status Prediction Models in Early-Onset Colorectal Cancer.

PURPOSE: In artificial intelligence-based modeling, working with a limited number of patient groups is challenging. This retrospective study aimed to evaluate whether applying synthetic data generation methods to the clinical data of small patient groups can enhance the performance of prediction models. MATERIALS AND METHODS: A data set collected by the Cancer Registry Library Project from the Yonsei Cancer Center (YCC), Severance Hospital, between January 2008 and October 2020 was reviewed. Patients with colorectal cancer younger than 50 years who started their initial treatment at YCC were included. A Bayesian network-based synthesizing model was used to generate a synthetic data set, combined with the differential privacy (DP) method. RESULTS: A synthetic population of 5,005 was generated from a data set of 1,253 patients with 93 clinical features. The Hellinger distance and correlation difference metric were below 0.3 and 0.5, respectively, indicating no statistical difference. The overall survival by disease stage did not differ between the synthetic and original populations. Training with the synthetic data and validating with the original data showed the highest performances of 0.850, 0.836, and 0.790 for the Decision Tree, Random Forest, and XGBoost models, respectively. Comparison of synthetic data sets with different epsilon parameters from the original data sets showed improved performance >0.1%. For extremely small data sets, models using synthetic data outperformed those using only original data sets. The reidentification risk measures demonstrated that the epsilons between 0.1 and 100 fell below the baseline, indicating a preserved privacy state. CONCLUSION: The synthetic data generation approach enhances predictive modeling performance by maintaining statistical and clinical integrity, and simultaneously reduces privacy risks through the application of DP techniques.

Prognostic value of baseline and early treatment response of neutrophil-lymphocyte ratio, C-reactive protein, and lactate dehydrogenase in non-small cell lung cancer patients undergoing immunotherapy.

Background: Not all non-small cell lung cancer (NSCLC) patients will benefit from immune checkpoint therapy and use of these medications carry serious autoimmune adverse effects. Therefore, biomarkers are needed to better identify patients who will benefit from its use. Here, the correlation of overall survival (OS) with baseline and early treatment period serum biomarker responses was evaluated in patients with NSCLC undergoing immunotherapy. Methods: Patients diagnosed with NSCLC undergoing immunotherapy (n=597) at a tertiary academic medical center in South Korea were identified between January 2010 and November 2021. The neutrophil-lymphocyte ratio (NLR), C-reactive protein (CRP), and lactate dehydrogenase (LDH) levels in the survival and non-survival groups were examined at baseline and early treatment periods. Additionally, aberrant laboratory parameters at each period were used to stratify survival curves and examine their correlation with one-year OS. Results: In the non-survival group, the NLR, CRP, and LDH levels at the early treatment period were higher than those at the baseline (P<0.001). The survival curves stratified based on aberrant laboratory findings in each period varied (log-rank test P<0.001). Multivariate Cox regression analysis revealed that having prescribed more than 3rd line of chemotherapy [hazard ratio (HR) =3.19, 95% confidence interval (CI): 1.04-9.82; P=0.043] and early treatment period CRP (HR =3.88; 95% CI: 1.55-9.72; P=0.004) and LDH (HR =4.04; 95% CI: 2.01-8.12; P<0.001) levels were significant predictors of one-year OS. Conclusions: Early treatment period CRP and LDH levels were significant predictors of OS in patients with NSCLC undergoing immunotherapy.

Correction of Condylar Displacement of the Mandible Using Early Screw Removal following Patient-Customized Orthognathic Surgery.

OBJECTIVE: Orthognathic surgery (OGS) is a surgical intervention that corrects dentofacial deformities through the movement of maxillary and mandibular segments to achieve adequate masticatory function, joint health, and facial harmony. However, some patients present with occlusal discrepancies, condylar sag, and/or temporomandibular disorders after OGS. Various methods have been employed to solve these problems after surgery. This study aimed to evaluate the effectiveness of early screw removal in patients with occlusal discrepancies after OGS using three-dimensional cone-beam computed tomography (CBCT). METHODS: In 44 patients with dentofacial deformities, patient-customized OGSs with customized plates were performed to correct facial deformities using customized guides with computer-aided surgical simulation. Of the 44 patients, eight patients complained of occlusal discrepancies and temporomandibular disorders after OGS. These eight patients underwent screw removal under local anesthesia around four weeks. The temporomandibular joint spaces at three time points (pre-surgical, post-surgical, and after screw removal) in the sagittal and coronal planes were compared using CBCT. RESULTS: Eight patients showed an increase in joint space on CBCT images immediately after surgery (T1), but after early screw removal (T2), these spaces almost returned to their pre-surgical state, and the temporomandibular joint problem disappeared. CONCLUSIONS: The removal of screws located in the distal segment under local anesthesia between three and four weeks post-surgically may be a treatment option for patients with post-OGS occlusal discrepancies, condylar sag, and/or temporomandibular disorder.

Sagittal Relationship between the Maxillary Central Incisors and the Forehead in Digital Twins of Korean Adult Females.

OBJECTIVE: Digital twins of adult Korean females were created as a tool to evaluate and compare the sagittal relationship between the maxillary central incisors and the forehead before and after orthodontic treatment. METHODS: Digital twins were reconstructed for a total of 50 adult female patients using facial scans and cone-beam computed tomography (CBCT) images. The anteroposterior position of the maxillary central incisor and the forehead inclination were measured. RESULTS: The control group presented a mean of 6.7 mm for the sagittal position and 17.5° for forehead inclination. The study group showed a mean of 9.3 mm for the sagittal position and 13.6° for forehead inclination. Most Korean females seeking orthodontic treatment had their maxillary central incisor anterior to the glabella. In contrast, fewer Korean females who completed their orthodontic treatments had their maxillary central incisor anterior to the glabella. Furthermore, patients who had completed the orthodontic treatment were more likely to have the maxillary central incisor between the forehead facial axis and glabella. CONCLUSION: The use of digital twins for three-dimensional (3D) analysis of the profile implies a high clinical significance. In addition, as the facial profile of Koreans is different from that of Caucasians, careful consideration should be made when setting treatment goals for the anteroposterior position of the maxillary central incisors.

Transforaminal Endoscopic Discectomy for Hard or Calcified Lumbar Disc Herniation: A New Surgical Technique and Clinical Outcomes.

OBJECTIVE: Hard or calcified discs are often adherent to surrounding nerve tissue. The whole herniated disc is difficult to remove by pulling part of the hernia mass, which makes obtaining good results through endoscopic treatment difficult. The purpose of this study was to describe the details of the transforaminal endoscopic lumbar discectomy technique for a hard or calcified disc and report the clinical results. METHODS: From October 2016 to June 2019, 43 consecutive cases diagnosed as hard or calcified lumbar disc herniation at our institution and treated with transforaminal endoscopic discectomy were evaluated. Endoscopic decompression was performed in patients with hard or calcified lumbar disc herniation. RESULTS: The preoperative visual analog scale score for leg pain (mean ± standard deviation) was 7.09 ± 1.74. The score improved to 2.55 ± 1.35 at 1 week postoperatively, 1.88 ± 1.29 at 4 weeks postoperatively, and 1.58 ± 1.0 at 26 weeks postoperatively (P < 0.01 for all). The preoperative Oswestry Disability Index (mean ± standard deviation) was 55.4 ± 23.04, which improved to 30.89 ± 13.64 at 1 week postoperatively, 23.08 ± 11.64 at 4 weeks postoperatively, and 16.42 ± 9.76 at 26 weeks postoperatively (P < 0.01 for all). Two patients developed a dural laceration. Both patients were discharged after several hours of observation. None of the patients had postoperative infection, epidural hematoma, or delayed neurological deterioration. CONCLUSIONS: Transforaminal endoscopic discectomy could be an effective treatment method for a selected group of patients with hard or calcified lumbar disc herniation.

A Simple and Safe Approach for Maxillary Sinus Augmentation with the Advanced Surgical Guide.

OBJECTIVE: The development of digital dentistry has contributed to the astonishing advancement of implant dentistry. Furthermore, digital technology is expected to be applied extensively to sinus augmentation, which is an advanced technique for implant surgery. This study introduces a simple method for a safer and more precise lateral window opening for sinus augmentation using a navigation program. METHODS: Five eligible patients with residual alveolar bone of 4 mm or less are presented, requiring lateral approach for sinus augmentation. Navigation system was opted for the sinus lift with simultaneous implant placement. Virtual planning started with establishing the adequate position of the lateral window based on the radiographic images and the scanned file of the dentition. The position of the window was indicated on the guide within the program. Afterwards, the virtually designed surgical guide was fabricated either with 3D printer or milling machine for the actual surgery. RESULTS: All the patients who underwent surgery with the surgical guide showed no sign of clinical complications including pain, swelling, nausea, epistaxis, or early loss of the implants. Results of radiographic evaluation also showed adequate placement of the implants in a pre-planned position, and the sinus window was also formed in the desired location. CONCLUSION: Lateral window opening combined with digital navigation system is believed to be a promising technique for a more precise as well as safer sinus augmentation.

Long-term Stability after Reduction of Mandible Fracture by Keyhole Plate: Evaluation at the Time of Plate Removal.

BACKGROUND: Various types of miniplates have been developed and used for the reduction of facial bone fractures. We introduced Yang's Keyhole (YK) plate, and reported on its short-term stability. The purpose of this study was to evaluate the long-term stability of the YK plate, as a follow-up study, by examining the patients who had used the YK plate among the patients with the reduction of mandible fractures and who visited for plate removal. METHODS: We reviewed the medical records of 16 patients who underwent mandibular fracture fixation using a YK plate (group I) and 17 patients who underwent mandibular fracture fixation using a conventional plate (group II). Assessment was then made on malunion, occlusal stability, discomfort during the application, and clinical symptoms. RESULTS: From January 2015 to December 2017, a total of 36 patients underwent mandibular fracture surgery using a YK plate. A total of 16 patients received plate removal. Among them, 15 were male and 1 female. The average age was 26 years. The applied surgical sites were the 12 on mandibular angle, 4 on mandibular symphysis, and 2 on subcondyle. The application period of YK plate was an average of 335 days. During the same period, 45 people underwent surgery on the conventional plate. A total of 17 patients received plate removal. Among them, 15 were male and 2 females. The average age was 36 years. The applied surgical sites were the 8 on mandibular angle, 4 on mandibular symphysis, and 2 on subcondyle. The application period of the conventional plate was an average of 349 days. No malocclusion occurred at the time of removal, and occlusion was stable. No patient complained of joint disease or discomfort. CONCLUSION: The YK plate system, in which the screw was first inserted and the plate was applied, for clinical convenience did not cause any particular problem and no significant difference from the conventional plate.

Transforaminal Endoscopic Decompression for Lumbar Spinal Stenosis: A Novel Surgical Technique and Clinical Outcomes.

OBJECTIVE: Transforaminal endoscopic treatment has been reported to be an effective treatment option in patients with lumbar disc herniation. However, it is rarely performed for spinal stenosis because of the limitation of endoscopic working mobility caused by the exiting nerve root and foraminous bony structure. The objective of this study was to describe a novel transforaminal endoscopic decompression technique for spinal stenosis and report the clinical results. METHODS: From October 2015 to October 2016, 30 consecutive cases were diagnosed as lateral recess stenosis in our institution and underwent transforaminal endoscopic decompression. Visual analog scale (VAS) of back and leg pain and the Oswestry Disability Index (ODI) were measured preoperatively and at follow-up. RESULTS: The mean ± SD value of preoperative VAS leg pain score was 7.6 ± 1.17. The score improved to 2.2 ± 1.11 at 1 week postoperatively, 1.73 ± 0.96 at 4 weeks postoperatively, and 1.63 ± 0.95 at 26 weeks postoperatively (P < 0.01). The mean ± SD value of the preoperative ODI score was 65.69 ± 14.22. The score improved to 24.29 ± 11.89 at 1 week postoperatively, 21.25 ± 9.25 at 4 weeks postoperatively, and 15.62 ± 10.49 at 26 weeks postoperatively (P < 0.01). There were no patients with postoperative infection, dural tear, delayed neurologic deterioration, or conversion to open surgery. CONCLUSIONS: Transforaminal endoscopic decompression under local anesthesia could be an effective treatment method for the selected group of patients with spinal stenosis.

Clinical application of 3D-printed-step-bolus in post-total-mastectomy electron conformal therapy.

The 3D-printed boluses were used during the radiation therapy of the chest wall in six patients with breast cancer after modified radical mastectomy (MRM). We measured the in-vivo skin doses while both conventional and 3D-printed boluses were placed on the chest wall and compared the mean doses delivered to the ipsilateral lung and the heart. The homogeneity and conformity of the dose distribution in the chest wall for both types of boluses were also evaluated. The uniformity index on the chest skin was improved when the 3D-printed boluses were used, with the overall average skin dose being closer to the prescribed one in the former case (-0.47% versus -4.43%). On comparing the dose-volume histogram (DVH), it was found that the 3D-printed boluses resulted in a reduction in the mean dose to the ipsilateral lung by up to 20%. The precision of dose delivery was improved by 3% with the 3D-printed boluses; in contrast, the conventional step bolus resulted in a precision level of 5%. In conclusion, the use of the 3D-printed boluses resulted in better dose homogeneity and conformity to the chest wall as well as the sparing of the normal organs, especially the lung. This suggested that their routine use on the chest wall as a therapeutic approach during post-mastectomy radiation therapy offers numerous advantages over conventional step boluses.

Therapeutic effect of topical application of curcumin during treatment of radiation burns in a mini-pig model.

Curcumin protects the skin against radiation-induced epidermal damage and prevents morphological changes induced by irradiation skin, thereby maintaining the epidermal thickness and cell density of basal layers. In this study, the effects of topical curcumin treatment on radiation burns were evaluated in a mini-pig model. Histological and clinical changes were observed five weeks after radiation exposure to the back (6°Co gamma-radiation, 50 Gy). Curcumin was applied topically to irradiated skin (200 mg/cm²) twice a day for 35 days. Curcumin application decreased the epithelial desquamation after irradiation. Additionally, when compared to the vehicle-treated group, the curcumin-treated group showed reduced expression of cyclooxygenase-2 and nuclear factor-kappaB. Furthermore, irradiation prolonged healing of biopsy wounds in the exposed area, whereas curcumin treatment stimulated wound healing. These results suggest that curcumin can improve epithelial cell survival and recovery in the skin and therefore be used to treat radiation burns.

Outcome of conservative percutaneous cholecystostomy in high-risk patients with acute cholecystitis and risk factors leading to surgery.

BACKGROUND: Laparoscopic cholecystectomy (LC) is the treatment of choice for acute cholecystitis. However, the morbidity and mortality rates are high in elderly patients or in those with co-morbidities at the time of surgery. Percutaneous cholecystostomy (PC) is a safe treatment for acute inflammation of the gall bladder. This study aimed to evaluate the safety and efficacy of PC for acute cholecystitis and investigate the post-PC factors leading to subsequent LC. MATERIALS AND METHODS: Ninety-three patients with acute cholecystitis who underwent PC between August 2006 and December 2012 were retrospectively reviewed for clinical course, outcomes, and prognosis. We evaluated patient age, the presence of co-morbidities, American Society of Anesthesiologists (ASA) score, duration of drainage of the PC tube, performance of LC, conversion rate, hospital stay, recurrence, and 30-day mortality. We compared these characteristics in two study groups: 31 were treated with only conservative PC (group I) and 62 with PC followed by elective LC (group II). RESULTS: Patients in group I were older than those in group II (80.38 ± 10.05 vs. 70.50 ± 11.81 years, p < 0.001). More group I patients had an ASA score of III or IV (deemed high risk for surgery) compared to group II patients (80.6 %, n = 25 vs. 37.0 %, n = 23, p = 0.0012). Age, ASA score, and cerebrovascular accident (CVA) were significantly correlated when analyzing factors used to decide surgery (R (2) = 0.15, p < 0.001; R (2) = 0.21, p < 0.001; R (2) = 0.05, p = 0.05, respectively). Two patients in group I died within 30 days. Six patients (19.3 %) in group I experienced recurrent cholecystitis after PC tube removal. CONCLUSIONS: PC is a safe and effective therapeutic option in high-risk patients with acute cholecystitis, or for preoperative management. The decisive risk factors for surgery after PC were age, ASA score, and CVA.

Radiation-induced eosinophilic, polymorphic, and pruritic eruption in a pig skin model.

Eosinophilic, polymorphic and pruritic eruption associated with radiotherapy (EPPER) can occur in cancer patients after irradiation. In this study, we characterized the clinical and histopathological features of pig skin that developed widespread polymorphic and pruritic skin lesions following localized 50 Gy gamma-irradiation. The pigs developed pruritus 5-7 weeks after irradiation, and infiltration of the dermis by eosinophils was detected 4-7 weeks after irradiation. The irradiated animals also showed transiently increased numbers of peripheral eosinophils 5-7 weeks after treatment. Irradiation induced desquamation after 2-4 weeks, which and the desquamation gradually resolved after 7 weeks. These pathological changes correspond to those seen in irradiated human skin, indicating that this model could be useful for elucidating the pathogenesis of EPPER and for developing therapeutic and prophylactic methods.

ß-irradiation (¹66Ho patch)-induced skin injury in mini-pigs: effects on NF-κB and COX-2 expression in the skin.

In the present study, the detrimental effect of ß-emission on pig skin was evaluated. Skin injury was modeled in mini-pigs by exposing the animals to 50 and 100 Gy of ß-emission delivered by (166)Ho patches. Clinicopathological and immunohistochemical changes in exposed skin were monitored for 18 weeks after ß-irradiation. Radiation induced desquamation at 2~4 weeks and gradual repair of this damage was evident 6 weeks after irradiation. Changes in basal cell density and skin depth corresponded to clinically relevant changes. Skin thickness began to decrease 1 week after irradiation, and the skin was thinnest 4 weeks after irradiation. Skin thickness increased transiently during recovery from irradiation-induced skin injury, which was evident 6~8 weeks after irradiation. Epidermal expression of nuclear factor-kappa B (NF-κB) differed significantly between the untreated and irradiated areas. One week after irradiation, cyclooxygenase-2 (COX-2) expression was mostly limited to the basal cell layer and scattered among these cells. High levels of COX-2 expression were detected throughout the full depth of the skin 4 weeks after irradiation. These findings suggest that NF-κB and COX-2 play roles in epidermal cell regeneration following ß-irradiation of mini-pig skin.

Proton pump inhibitor administration delays rebleeding after endoscopic gastric variceal obturation.

AIM: To clarify the efficacy of proton pump inhibitors (PPIs) after endoscopic variceal obturation (EVO) with N-butyl-2-cyanoacrylate. METHODS: A retrospective study was performed on 16 liver cirrhosis patients with gastric variceal bleeding that received EVO with injections of N-butyl-2-cyanoacrylate at a single center (Kyung Hee University Hospital at Gangdong) from January 2008 to December 2012. Medical records including patient characteristics and endoscopic findings were reviewed. Treatment results, liver function, serum biochemistry and cirrhosis etiology were compared between patients receiving PPIs and those that did not. Furthermore, the rebleeding interval was compared between patients that received PPI treatment after EVO and those who did not. RESULTS: The patient group included nine males and seven females with a mean age of 61.8 ± 11.7 years. Following the EVO procedure, eight of the 12 patients that received PPIs and three of the four non-PPI patients experienced rebleeding. There were no differences between the groups in serum biochemistry or patient characteristics. The rebleeding rate was not significantly different between the groups, however, patients receiving PPIs had a significantly longer rebleeding interval compared to non-PPI patients (22.2 ± 11.2 mo vs 8.5 ± 5.5 mo; P = 0.008). The duration of PPI use was not related to the rebleeding interval. A total of six patients, who had ulcers at the injection site, exhibited a shorter rebleeding interval (16.8 ± 5.9 mo) than patients without ulcers (19.9 ± 3.2 mo), though this difference was not statistically significant. CONCLUSION: PPI therapy can extend the rebleeding interval, and should therefore be considered after EVO treatment for gastric varices.

Comparison of peripheral arterial tonometry and flow-mediated vasodilation for assessment of the severity and complexity of coronary artery disease.

OBJECTIVE: Noninvasive flow-mediated vasodilation (FMD) is a widely used method to assess endothelial function, but its technical difficulty and problems remain obstacles for use in clinical practice. Reactive hyperemia-peripheral arterial tonometry (RH-PAT) was developed as a simpler and more reproducible method. We compared FMD and RH-PAT in patients with stable angina. Furthermore, the differences in these two techniques according to coronary artery disease (CAD) severity and complexity were also assessed. MATERIALS AND METHODS: We consecutively enrolled 80 patients who underwent elective coronary angiography. Endothelial function was assessed before angiography using brachial artery FMD and RH-PAT. The complexity and extent of the coronary lesions were assessed angiographically. The extent of CAD was defined as the number of diseased coronary arteries (>70%) and complexity of CAD was assessed by the SYNTAX score algorithm. RESULTS: In the overall study group (61±9 years, 57% men), the mean FMD was 8.5±5.1% and the mean reactive hyperemia index (RHI) measured by RH-PAT was 1.7±0.4. A significant correlation was observed between FMD and RHI irrespective of sex, diabetes, or presence of CAD. FMD and RHI were significantly lower in patients with multivessel and complex CAD. A receiver-operating characteristic curve analysis showed that both techniques were comparable in terms of predicting the presence of CAD and complexity. CONCLUSION: Assessment of RH-PAT could be a less operator-dependent and noninvasive method of evaluating vascular endothelial function in patients with stable angina.

Predicting factors for stent failure-free survival in patients with a malignant ureteral obstruction managed with ureteral stents.

PURPOSE: To determine predictive factors for stent failure-free survival in patients treated with a retrograde ureteral stent for a malignant ureteral obstruction. MATERIALS AND METHODS: We retrospectively reviewed 71 patients who underwent insertion of a cystoscopic ureteral stent due to a malignant ureteral obstruction between May 2004 and June 2011. Performance status, type of cancer, hydronephrosis grade, location of the obstruction, presence of bladder invasion, C-reactive protein (CRP), serum albumin, and inflammation-based prognostic score (Glasgow prognostic score, GPS) were assessed using a Cox proportional regression hazard model as predicting factors for stent failure. RESULTS: A univariate analysis indicted that hypoalbuminemia (<3.5 g/dL; hazard ratio [HR], 2.43; 95% confidence interval [CI], 1.21 to 4.86; p=0.012), elevated CRP (≥1 mg/dL; HR, 4.79; 95% CI, 2.0 to 11.1; p=0.001), and presence of a distal ureter obstruction (HR, 3.27; 95% CI, 1.19 to 8.95; p=0.021) were associated with stent failure-free survival. A multivariate analysis revealed that the presence of a mid and lower ureteral obstruction (HR, 3.27; 95% CI, 1.19 to 8.95; p=0.007), GPS ≥1 (HR, 7.22; 95% CI, 2.89 to 18.0; p=0.001), and elevated serum creatinine before ureteral stent placement (>1.2 mg/dL; HR, 2.16; 95% CI, 1.02 to 4.57; p=0.044) were associated with stent failure-free survival. CONCLUSIONS: A mid or lower ureteral obstruction, GPS ≥1, and serum creatinine before ureteral stent insertion >1.2 mg/dL were unfavorable predictors of stent failure-free survival. These factors may help urologists predict survival time.

Initial experience of transurethral resection with pediatric resectoscope for incomplete anterior urethral stricture.

PURPOSE: Endoscopic urethrotomy is an alternative method in treatment of urethral stricture. However, it have high recurrence rate because of the remained fibrotic tissue. Removal of the fibrotic tissue can maintain the patency of the urethral lumen after the procedure. We report the therapeutic efficacy of our initial experience using pediatric resectoscope for treating anterior urethral stricture in 16 cases. MATERIALS AND METHODS: From January 2009 to April 2011, transurethral resection with pediatric resectoscope was primarily performed on 16 patients with anterior urethral stricture. Retrograde urethrography, uroflowmetry, postvoid residual volume, IPSS score and QoL score were performed preoperatively. We used 11.5Fr pediatric resectoscope (Wolf) and monopolar electrosurgical generator. The stricture was incised under vision at the 12 o'clock location or the site of maximum scar tissue or narrowing in asymmetric strictures for working space. After incision, transurethral resection with pediatric resectoscope was performed to all scar tissues. Monopolar cutting current was set on 45 watt and coagulation current was set on 30 watt, fulgurate mode. Postoperatively, drainage of the bladder was performed for 7 days using an 18F latex catheter. Patients were followed up by IPSS score, QoL score, uroflowmetry and postvoid residual volume. RESULTS: Successful results without recurrence were achieved in 11 of 16 patients. Postoperative urethral dilation had been performed average 2.4 times (0~6 times). When we classified the results by etiology, the number of successful results in strictures with a trauma, iatrogenic, or unknown cause was 5 (7/11), 3 (3/4) and 1 (1/1), respectively. In 5 patients who failed treatment, we repeated transurethral resection with pediatric resectoscope in 1 patient, and periodic urethral dilation in 4 patients. No operative complications occurred in any patients. CONCLUSIONS: Transurethral resection with pediatric resectoscope is an effective therapeutic method for anterior urethral stricture. More long-term follow-up and large scale studies are needed to confirm the efficacy of this procedure.

Initial Experience of Transurethral Resection with Pediatric Resectoscope for Incomplete Anterior Urethral Stricture

Purpose Endoscopic urethrotomy is an alternative method in treatment of urethral stricture. However, it have high recurrence rate because of the remained fibrotic tissue. Removal of the fibrotic tissue can maintain the patency of the urethral lumen after the procedure. We report the therapeutic efficacy of our initial experience using pediatric resectoscope for treating anterior urethral stricture in 16 cases. Materials and Methods From January 2009 to April 2011, transurethral resection with pediatric resectoscope was primarily performed on 16 patients with anterior urethral stricture. Retrograde urethrography, uroflowmetry, postvoid residual volume, IPSS score and QoL score were performed preoperatively. We used 11.5Fr pediatric resectoscope (Wolf) and monopolar electrosurgical generator. The stricture was incised under vision at the 12 o'clock location or the site of maximum scar tissue or narrowing in asymmetric strictures for working space. After incision, transurethral resection with pediatric resectoscope was performed to all scar tissues. Monopolar cutting current was set on 45 watt and coagulation current was set on 30 watt, fulgurate mode. Postoperatively, drainage of the bladder was performed for 7 days using an 18F latex catheter. Patients were followed up by IPSS score, QoL score, uroflowmetry and postvoid residual volume. Results Successful results without recurrence were achieved in 11 of 16patients. Postoperative urethral dilation had been performed average 2.4 times (0∼6 times). When we classified the results by etiology, the number of successful results in strictures with a trauma, iatrogenic, or unknown cause was 5 (7/11), 3 (3/4) and 1 (1/1), respectively. In 5 patients who failed treatment, we repeated transurethral resection with pediatric resectoscope in 1 patient, and periodic urethral dilation in 4 patients. No operative complications occurred in any patients. Conclusions Transurethral resection with ...

Severe Hyponatremia Associated with the Use of Angiotensin II Receptor Blocker/thiazide Combinations.

There are several widely used combinations of angiotensin II receptor blocker (ARB)/thiazide. The complimentary mechanism of action for such anti-hypertensive therapies is that, while ARB inhibits the vasoconstricting and aldosterone-secreting effects of angiotensin II, hydrochlorothiazide affects the renal tubular mechanisms of electrolyte reabsorption and increases excretion of sodium and chloride in the distal tubule, consequently promoting water excretion. In addition, hypokalemia, which may be triggered by a hydrochlorothiazide-induced increase in urinary potassium loss, is resisted by the use of ARB. Hence, the ARB/thiazide combination is safe in terms of potassium imbalance. For these reasons, fixed-dose ARB/thiazide combination anti-hypertensive drugs have been widely used for the treatment of hypertension. However, there have not been many studies done regarding cases where patients under such regimens showed severe hyponatremia, even when the amount of thiazide included was low. Here we report two cases in which severe hyponatremia occurred following treatment with the ARB/thiazide combinations. Upon discontinuation of the regimen, both patients showed recovery from hyponatremia.