Intraoperative Patient Selection for Tubeless Percutaneous Nephrolithotomy

This study was conducted to report our experience of intraoperative patient selection for tubeless percutaneous nephrolithotomy (PCNL) based on a tentative decision-making algorithm. Thirty-four consecutive patients who were scheduled to undergo tubeless PCNL were included and medical records were obtained from a prospectively maintained database for these patients. After completion of PCNL, the nephrostomy site was observed with a safety guidewire in place. If there was no significant bleeding through the tract, tubeless PCNL was performed, and in cases with significant bleeding or other complications, nephrostomy catheter insertion was performed as usual. In 29 cases (85.3%), tubeless PCNL was performed according to our decision-making protocol. Mean stone size was 7.33 ± 9.35 cm². Mean hospital stay was 2.61 ± 1.01 days. The difference between preoperative and postoperative hemoglobin was 0.68 ± 1.22 g/dL (p > 0.05). Visual analog pain scale scores immediately post-operation, on postoperative day one and on the day of discharge were 4.62 ± 1.80, 3.25 ± 1.68 (postoperative day one vs. operative day; p = 0.001), and 1.87 ± 0.83 (the day of discharge vs. operative day; p = 0.001), respectively. The success rate with insignificant remnant stones was 85.2% and complete stone-free rate was 76.5%. In conclusion, tubeless PCNL was performed successfully with low complication rate and reduced pain score through our decision-making algorithm.Key words: Renal stone, Percutaneous nephrolithotomy, Tubeless, Patient selectionCurrently, percutaneous nephrolithotomy (PCNL) is the treatment of choice for large, complex renal stones due to low postoperative morbidity and low complication rate.^1,2 Placement of a nephrostomy catheter is done routinely after PCNL, as it provides proper drainage of urine, prevention of urinary extravasation and tamponade of bleeding.^3,4 In addition, it might be used for a tract for a second-look PCNL.⁵Recently, the need for placement of a nephrostomy catheter has been questioned due to an increase in postoperative discomfort, low incidence of second-look operation, and increase in morbidity.^6,7 Tubeless PCNL has been attempted with proper drainage of urine through an indwelling anterograde stent instead of a nephrostomy tube, or alternatively without an internal stent at all.⁸ Tubeless PCNL is not yet widespread despite the potential benefits of this approach, because there has been a concern for potentially fatal complications such as massive bleeding without a nephrostomy tube.⁹ Several studies have demonstrated the feasibility of tubeless PCNL for the last two decades; however, it has not been determined how to choose patients to undergo either conventional PCNL or tubeless PCNL. Therefore, this study was conducted to report our experience of intraoperative patient selection for tubeless PCNL based on a tentative decision-making algorithm.     

Thiosulfate Reduces Calcium Phosphate Nephrolithiasis

An uncontrolled trial reported that sodium thiosulfate reduces formation of calcium kidney stones in humans, but this has not been established in a controlled human study or animal model. Using the genetic hypercalciuric rat, an animal model of calcium phosphate stone formation, we studied the effect of sodium thiosulfate on urine chemistries and stone formation. We fed genetic hypercalciuric rats normal food with or without sodium thiosulfate for 18 wk and measured urine chemistries, supersaturation, and the upper limit of metastability of urine. Eleven of 12 untreated rats formed stones compared with only three of 12 thiosulfate-treated rats (P < 0.002). Urine calcium and phosphorus were higher and urine citrate and volume were lower in the thiosulfate-treated rats, changes that would increase calcium phosphate supersaturation. Thiosulfate treatment lowered urine pH, which would lower calcium phosphate supersaturation. Overall, there were no statistically significant differences in calcium phosphate supersaturation or upper limit of metastability between thiosulfate-treated and control rats. In vitro, thiosulfate only minimally affected ionized calcium, suggesting a mechanism of action other than calcium chelation. In summary, sodium thiosulfate reduces calcium phosphate stone formation in the genetic hypercalciuric rat. Controlled trials testing the efficacy and safety of sodium thiosulfate for recurrent kidney stones in humans are needed.Nephrolithiasis is one of the most common disorders of the urinary tract, affecting approximately 12% of men and 6% of women during their lifetimes in industrialized countries.¹ Approximately 80% of kidney stones are composed primarily of calcium salts. Despite the high prevalence of kidney stone disease, there has been little progress in developing new therapies to prevent stone formation, especially in patients who have formed a kidney stone and who are at significantly increased risk for forming additional stones. The lack of progress in identifying new therapies for nephrolithiasis has been disappointing to the many patients who experience recurrent stone formation.Sodium thiosulfate (STS), Na₂S₂O₃, is a compound with a long history of medicinal use.^2,3 Currently, it is used for treatment of cyanide toxicity and as a neutralizing agent to reduce the toxicity of cisplatin chemotherapy.^4–6 The effectiveness of STS in these diseases lies in its antioxidant activity and the availability of a sulfur group for donation. In 1985, Yatzidis⁷ reported on using STS as treatment for recurrent calcium nephrolithiasis. In a 4-yr study of 34 patients, he reported an 80% reduction in stone rates, compared with the patients’ own pretreatment stone formation rate. Unfortunately, no follow-up, prospective, controlled trials have been performed to determine the effectiveness of STS in preventing recurrent stone formation; however, anecdotal reports of successful treatment of calciphylaxis with STS in patients with end-stage kidney disease have stimulated interest in this compound as a potential therapy for disorders of calcium deposition, including stone disease.^8–16 The mechanism by which STS affects calcium deposition is not known.Before pursuing new studies in humans, we chose first to study this drug in the genetic hypercalciuric stone-forming (GHS) rats because 40 to 50% of humans with kidney stones will have hypercalciuria, making it the most common metabolic abnormality. The GHS rat colony has been bred for hypercalciuria and now excretes approximately 8 to 10 times more urine calcium than similarly fed control rats.¹⁷ The pathophysiology of the hypercalciuria seems similar to that in humans in that it involves intestinal hyperabsorption,^18,19 reduced renal tubular reabsorption,²⁰ and increased bone mineral lability.^21,22 Virtually all of the GHS rats form kidney stones, whereas control rats have no evidence of stone formation.²³ On a standard rat diet, the kidney stones formed contain only calcium and phosphate.²⁴ Here we report the results of a controlled trial to determine whether STS reduces stone formation in an animal model of spontaneous calcium phosphate stone formation.     

Activity,Energy Intake,Obesity, and the Risk of Incident Kidney Stones in Postmenopausal Women: A Report from the Women’s Health Initiative

Obesity is a strong risk factor for nephrolithiasis, but the role of physical activity and caloric intake remains poorly understood. We evaluated this relationship in 84,225 women with no history of stones as part of the Women’s Health Initiative Observational Study, a longitudinal, prospective cohort of postmenopausal women enrolled from 1993 to 1998 with 8 years’ median follow-up. The independent association of physical activity (metabolic equivalents [METs]/wk), calibrated dietary energy intake, and body mass index (BMI) with incident kidney stone development was evaluated after adjustment for nephrolithiasis risk factors. Activity intensity was evaluated in stratified analyses. Compared with the risk in inactive women, the risk of incident stones decreased by 16% in women with the lowest physical activity level (adjusted hazard ratio [aHR], 0.84; 95% confidence interval [95% CI], 0.74 to 0.97). As activity increased, the risk of incident stones continued to decline until plateauing at a decrease of approximately 31% for activity levels ≥10 METs/wk (aHR, 0.69; 95% CI, 0.60 to 0.79). Intensity of activity was not associated with stone formation. As dietary energy intake increased, the risk of incident stones increased by up to 42% (aHR, 1.42; 95% CI, 1.02 to 1.98). However, intake <1800 kcal/d did not protect against stone formation. Higher BMI category was associated with increased risk of incident stones. In summary, physical activity may reduce the risk of incident kidney stones in postmenopausal women independent of caloric intake and BMI, primarily because of the amount of activity rather than exercise intensity. Higher caloric intake further increases the risk of incident stones.The prevalence of kidney stones is 8.8%, or 1 in 11 people, in the United States, and during the last 15 years the prevalence has increased by almost 70%.¹ The increased prevalence is especially pronounced among women and may be due to increased rates of obesity, weight gain, and metabolic syndrome.^1–3 Most visits for kidney stones occur in the outpatient setting. From 1992 to 2000, physician office visits primarily for kidney stones increased 43%, representing up to 1,825,000 annual visits.⁴ This represents a significant burden of disease, and additional efforts are needed to help with prevention.The increase in the prevalence of kidney stones has paralleled epidemic rates of obesity.⁵ In multiple prior studies, obesity has been recognized as a strong and consistent risk factor for kidney stones.^2,6–9 The cause of this increased risk is not well understood. Although obesity and higher body mass index (BMI) are associated with changes in urinary pH and electrolytes, the link with nephrolithiasis probably involves more than an increased solute load due to excess nutrient intake.^{6–8,10–12} It has been hypothesized that the proinflammatory state is associated with obesity and that metabolic syndrome may lead to stone formation.^13,14Several dietary factors have been linked to an increased risk of kidney stones.^9,15–18 For example, in clinical practice we recommend increased fluid intake, low sodium and low animal-protein intake, and normal calcium intake because these have all been shown to reduce stone recurrence.^19–21 Patients are often interested in dietary modification to prevent stone recurrence.²²A person’s present-day BMI reflects their historic balance between energy intake and energy expenditure. A restriction in dietary energy intake or increase in energy expenditure might partially offset the risk of stone formation imparted by BMI. The purpose of this study was to evaluate the independent relationship between physical activity, dietary energy intake, and BMI and the risk of incident kidney stone formation.     

DASH-Style Diet Associates with Reduced Risk for Kidney Stones

The impact of the Dietary Approaches to Stop Hypertension (DASH) diet on kidney stone formation is unknown. We prospectively examined the relation between a DASH-style diet and incident kidney stones in the Health Professionals Follow-up Study (n = 45,821 men; 18 yr of follow-up), Nurses'' Health Study I (n = 94,108 older women; 18 yr of follow-up), and Nurses'' Health Study II (n = 101,837 younger women; 14 yr of follow-up). We constructed a DASH score based on eight components: high intake of fruits, vegetables, nuts and legumes, low-fat dairy products, and whole grains and low intake of sodium, sweetened beverages, and red and processed meats. We used Cox hazards regression to adjust for factors that included age, BMI, and fluid intake. Over a combined 50 yr of follow-up, we documented 5645 incident kidney stones. Participants with higher DASH scores had higher intakes of calcium, potassium, magnesium, oxalate, and vitamin C and had lower intakes of sodium. For participants in the highest compared with the lowest quintile of DASH score, the multivariate relative risks for kidney stones were 0.55 (95% CI, 0.46 to 0.65) for men, 0.58 (95% CI, 0.49 to 0.68) for older women, and 0.60 (95% CI, 0.52 to 0.70) for younger women. Higher DASH scores were associated with reduced risk even in participants with lower calcium intake. Exclusion of participants with hypertension did not change the results. In conclusion, consumption of a DASH-style diet is associated with a marked decrease in kidney stone risk.Diet plays a major role in the development of kidney stones, and dietary changes likely have contributed to the substantial increase in nephrolithiasis over the past several decades.^1,2 A wide variety of dietary factors either promote or inhibit the formation of calcium oxalate kidney stones,^1,2 the most common type of stone.³Despite previously observed associations between individual dietary factors and kidney stone risk,² relatively few studies have examined the impact of overall diet or dietary patterns on risk. The identification of an effective stone prevention diet is difficult partly because most diets are isocaloric: if an individual reduces the intake of certain foods, he or she will increase the intake of other foods to maintain constant energy intake.⁴ As a result, consuming less of one dietary factor (such as animal protein⁵) to decrease stone risk may lead to the consumption of other factors (such as sucrose or fructose⁶) that increase risk.The Dietary Approaches to Stop Hypertension (DASH) diet, which is high in fruits and vegetables, moderate in low-fat dairy products, and low in animal protein represents a novel potential means of kidney stone prevention. The consumption of fruits and vegetables increases urinary citrate,⁷ an important inhibitor of calcium stone formation, and a diet with normal to high calcium content but low in animal protein and sodium decreases the risk of calcium oxalate stone recurrence by 51%.⁸ The DASH diet also lowers BP,⁹ which is particularly appealing given the high rates of prevalent and incident hypertension in stone formers.^10–14 Because the DASH diet would be expected to contain higher amounts of oxalate and vitamin C, both of which may increase calcium kidney stone risk,^15,16 the impact of the DASH diet on stone risk is currently unknown.To examine the relation between a DASH-style diet and the risk of incident kidney stones, we conducted prospective studies in three large cohorts: the Health Professionals Follow-up Study (HPFS), the Nurses'' Health Study I (NHS I), and the Nurses'' Health Study II (NHS II). Previously, we identified associations between individual dietary factors and stone risk in each of these study populations.^5,6,15–18 For the first time, we now report the impact of a specific dietary pattern on risk.     

The ROKS Nomogram for Predicting a Second Symptomatic Stone Episode

Most patients with first-time kidney stones undergo limited evaluations, and few receive preventive therapy. A prediction tool for the risk of a second kidney stone episode is needed to optimize treatment strategies. We identified adult first-time symptomatic stone formers residing in Olmsted County, Minnesota, from 1984 to 2003 and manually reviewed their linked comprehensive medical records through the Rochester Epidemiology Project. Clinical characteristics in the medical record before or up to 90 days after the first stone episode were evaluated as predictors for symptomatic recurrence. A nomogram was developed from a multivariable model based on these characteristics. There were 2239 first-time adult kidney stone formers with evidence of a passed, obstructing, or infected stone causing pain or gross hematuria. Symptomatic recurrence occurred in 707 of these stone formers through 2012 (recurrence rates at 2, 5, 10, and 15 years were 11%, 20%, 31%, and 39%, respectively). A parsimonious model had the following risk factors for recurrence: younger age, male sex, white race, family history of stones, prior asymptomatic stone on imaging, prior suspected stone episode, gross hematuria, nonobstructing (asymptomatic) stone on imaging, symptomatic renal pelvic or lower-pole stone on imaging, no ureterovesicular junction stone on imaging, and uric acid stone composition. Ten-year recurrence rates varied from 12% to 56% between the first and fifth quintiles of nomogram score. The Recurrence of Kidney Stone nomogram identifies kidney stone formers at greatest risk for a second symptomatic episode. Such individuals may benefit from medical intervention and be good candidates for prevention trials.The prevalence of nephrolithiasis in the United States population is increasing, and 9% of men and 6% of women have had a symptomatic stone episode.¹ After the first symptomatic kidney stone episode, knowledge regarding the risk of a second symptomatic episode would greatly help caregivers optimize prevention and management strategies. It is well known that patients with frequent symptomatic stone episodes are at increased risk for future episodes and need subspecialty care.² It is less clear which, if any, patients who have had only one symptomatic stone episode need more than modest dietary and lifestyle recommendations. If the subset at high risk for another episode can be identified, subspecialty evaluation with 24-hour urine chemistries, radiographic monitoring for stones, medical therapy, or more intensive dietary counseling may be of benefit. Early effective interventions may spare such individuals the morbidity of painful stone episodes and potential long-term complications, such as kidney failure.^3,4 Alternatively, those at low risk for a second episode would be spared the expense of subspecialty evaluations, potential harm from stone prevention medications, and a restrictive stone prevention diet (e.g., low dietary oxalate).Several studies have identified predictors for recurrence after the first stone episode,^5–9 although to our knowledge, no formal prediction tool has been developed for routine use in clinical care.¹⁰ Limitations of past studies include small sample size, inadequate ascertainment of potential predictors, and referral-based study populations (stone clinics). Previous studies combined symptomatic stone episodes with radiographic detection or growth of asymptomatic stones, but the latter is not a clinical event. It is the contribution of asymptomatic radiographic stones to the risk of symptomatic recurrence that is relevant to the patient. Patients seen in stone clinics have extensive laboratory evaluations but are also likely to have severe kidney stone disease that is recurrent. Conversely, most first-time symptomatic stone formers in the general population have a limited evaluation without urine chemistries.⁸This lack of medical intervention among most first-time stone formers provides an opportunity to study the natural history of symptomatic recurrence.⁸ We performed a general population cohort study of all validated incident kidney stone formers in Olmsted County, Minnesota, from 1984 to 2003 and followed them for a second episode. Our objective was to develop a prediction tool for stone formers to estimate risk of a second symptomatic episode using only characteristics commonly available at the time of the first episode.     

Renal sarcoma and associated malignant pulmonary embolism: a report of 2 cases

Renal sarcoma with venous tumour thrombus is usually an aggressive malignancy that necessitates complete surgical extirpation to achieve cure. Due to the rarity of these tumours, clinicians rely on case reports to better understand and treat patients with this disease. We recently encountered 2 patients with renal sarcoma who developed malignant pulmonary embolus. Our cases, combined with those previously published, suggest renal sarcoma tumour thrombus is at high risk for spontaneous and intraoperative embolization. This report details our experience and outlines measures that may decrease the rate of venous tumour embolization in patients with sarcoma.Sarcomas represent approximately 1% of primary renal neoplasms. To our knowledge, there are only 10 cases in the medical literature of postpubertal patients with primary renal sarcoma associated with inferior vena cava (IVC) tumour thrombus.^1–10 Of these cases, 3 suffered a malignant pulmonary embolus (PE).^4,6,8 We present 2 additional cases of renal sarcomas with IVC thrombus and malignant PE.     

Subsequent prostate cancer detection in patients with prostatic intraepithelial neoplasia or atypical small acinar proliferation

Introduction:

To evaluate the predictors of prostate cancer in follow-up of patients diagnosed on initial biopsy with high-grade prostatic intraepithelial neoplasia (HGPIN) or atypical small acinar proliferation (ASAP).

Methods:

We studied 201 patients with HGPIN and 22 patients with ASAP on initial prostatic biopsy who had subsequent prostatic biopsies. The mean time of follow-up was 17.3 months (range 1–62). The mean number of biopsy sessions was 2.5 (range 2–6), and the median number of biopsy cores was 10 (range 6–14).

Results:

On subsequent biopsies, the rate of prostate cancer was 21.9% (44/201) in HGPIN patients. Of these, 32/201 patients (15.9%), 9/66 patients (13.6%) and 3/18 patients (16.6%) were found to have cancer on the first, second and third follow-up biopsy sessions, respectively. In ASAP patients, the cancer detection rate was 13/22 (59.1%), all of whom were found on the first follow-up biopsy. There was a statistically significant difference between the cancer detection rate in ASAP and HGPIN patients (p < 0.001). Multivariate analysis showed that the independent predictors of cancer were the number of cores in the initial biopsy, the number of cores (> 10) in the follow-up biopsy and a prostate specific antigen (PSA) density of ≥ 0.15 (odds ratio 0.77, 3.46 and 2.7,8 respectively; p < 0.04). Conversely, in ASAP patients none of these variables were found to be associated with cancer diagnosis.

Conclusion:

ASAP is a strong predictive factor associated with cancer when compared with HGPIN. The factors predictive of cancer on follow-up biopsy of HGPIN are number of cores on initial biopsy, more than 10 cores in rebiopsy and elevated PSA density. As the cancer detection rate on repeated biopsy of HGPIN patients is the same as that of patients without HGPIN, perhaps the standard of repeat biopsy in all patients with HGPIN should be revisited.Owing to the widespread use of prostate specific antigen (PSA) as a screening tool for prostate cancer associated with increasing use of transrectal ultrasound (TRUS) guided prostate needle biopsy and the increasing number of sampling cores per biopsy, the histological findings of high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical small acinar proliferation (ASAP) has also increased.The detection rate of HGPIN in TRUS-guided needle biopsies performed owing to an elevated PSA level or an abnormal digital rectal examination (DRE), was found to be between 4% and 25% of patients^1–4 and the cancer detection rate on repeated biopsy was reported from 2% to 47% of patients.^1,3,5,6,7 Conversely, the rate of ASAP on initial biopsy was reported to range from 2.4% to 3.7%^3,8,9 the cancer detection rate on repeated biopsy was found to be as high as 52% in isolated ASAP^3,8,10 and 72% in ASAP associated with HGPIN.^3,11The management of patients found to have HGPIN on initial biopsy varies considerably, ranging from immediate rebiopsy to close observation at varying intervals.^12–15 Our aim was to examine our experience with prostatic rebiopsy in patients with HGPIN, ASAP or both.     

SLC26A6 and NaDC-1 Transporters Interact to Regulate Oxalate and Citrate Homeostasis

The combination of hyperoxaluria and hypocitraturia can trigger Ca²⁺-oxalate stone formation, even in the absence of hypercalciuria, but the molecular mechanisms that control urinary oxalate and citrate levels are not understood completely. Here, we examined the relationship between the oxalate transporter SLC26A6 and the citrate transporter NaDC-1 in citrate and oxalate homeostasis. Compared with wild-type mice, Slc26a6-null mice exhibited increased renal and intestinal sodium-dependent succinate uptake, as well as urinary hyperoxaluria and hypocitraturia, but no change in urinary pH, indicating enhanced transport activity of NaDC-1. When co-expressed in Xenopus oocytes, NaDC-1 enhanced Slc26a6 transport activity. In contrast, Slc26a6 inhibited NaDC-1 transport activity in an activity dependent manner to restricted tubular citrate absorption. Biochemical and physiologic analysis revealed that the STAS domain of Slc26a6 and the first intracellular loop of NaDC-1 mediated both the physical and functional interactions of these transporters. These findings reveal a molecular pathway that senses and tightly regulates oxalate and citrate levels and may control Ca²⁺-oxalate stone formation.Formation of calcareous stones is a major health problem, mainly afflicting the kidney¹ and salivary glands.² Most stones are Ca²⁺-oxalate, with the minority being Ca²⁺-phosphate.¹ Ca²⁺-oxalate stone formation can result from hyperoxaluria, hypercalciuria, or reduction in the major urinary Ca²⁺ buffer citrate.³ Ca²⁺-oxalate stones can form in the absence of hypercalciuria when hyperoxaluria is coupled with hypocitraturia. The anion transporter slc26a6 (National Center for Biotechnology Information [NCBI] accession no. {"type":"entrez-nucleotide","attrs":{"text":"NM_134420","term_id":"158341685","term_text":"NM_134420"}}NM_134420) has a major role in controlling systemic oxalate metabolism.⁴ Slc26a6 is expressed at high levels in most epithelia, including the proximal intestine, renal proximal tubule, salivary glands, and pancreas.⁵ Slc26a6 functions as a 1Cl⁻/2HCO₃ ⁶ or 1Cl⁻/1oxalate and 1Cl⁻/1formate exchanger.⁷ Its pivotal role in oxalate homeostasis was demonstrated in slc26a6^−/− mice, where the most prominent phenotype is increased serum and urine oxalate that lead to Ca²⁺-oxalate kidney stones.⁸Dietary oxalate is an important source of exogenous oxalate and is absorbed by the intestinal epithelium via the paracellular pathway.⁹ The liver is the main source of endogenous oxalate; however, under physiologic conditions, a small fraction of the bodily oxalate is derived from hepatic production.¹⁰ Studies using slc26a6^−/− mice showed that increased serum oxalate is the result of impaired intestinal excretion that, in turn, leads to increased filtered renal oxalate load and formation of Ca²⁺-oxalate stones.⁸ However, under normal physiologic conditions, two major factors prevent Ca²⁺-oxalate stones formation. Slc26a6 mediates oxalate clearance via the intestine,⁹ and urinary citrate chelates the Ca²⁺ to reduce the free Ca²⁺ available for binding to oxalate.¹¹ Citrate binds Ca²⁺ at a higher affinity than does oxalate;¹² thus, in the presence of a high citrate concentration, Ca²⁺-oxalate does not reach the super-saturation needed for stone formation. In addition, once crystals are formed, citrate adsorbs to the crystal surfaces and suppresses their growth and attachment to epithelia.¹³ By attaching to crystal surfaces, citrate also amplifies the protective effect of other stone inhibitors, such as the Tamm-Horsfall protein¹⁴ and osteopontin.¹⁵At a pH of 7.4, citrate is mostly in the form of a tricarboxylic acid, but it can be reabsorbed only by the proximal tubule epithelium in its divalent form.¹⁶ The luminal pH at the proximal tubule drops from 7.4 to 6.5,¹⁷ which favors the divalent form of citrate and thereby allows citrate transport. In mammals, the major luminal citrate transporter in both the intestine and proximal tubule is the Na⁺-dependent dicarboxylate co-transporter, NaDC-1 (NCBI accession no. {"type":"entrez-nucleotide","attrs":{"text":"AY186579","term_id":"28195240","term_text":"AY186579"}}AY186579).¹⁸ NaDC-1 (Slc13a2), the second member of the SLC13 family, has 11 transmembrane domains, with cytoplasmic N- and extracellular C-termini.¹⁸ In light of the importance of the citrate/oxalate balance in regulating free Ca²⁺ in bodily fluids, we hypothesized that citrate/oxalate balance may be regulated by a molecular mechanism that fine-tunes citrate and oxalate concentrations. Such a mechanism should involve the two major transporters, slc26a6 and NaDC-1.In the present work, we report on a new pathway that involves interplay between slc26a6 and NaDC-1 that determines citrate/oxalate homeostasis. The pathway involves the mutual but reciprocal regulation of slc26a6 (activation) and NaDC-1 (inhibition). The interaction between the oxalate and citrate transporters is mediated by the slc26a6 STAS domain and the NaDC-1 first intracellular loop (ICL1), which recapitulate the function of the full-length transporters. These findings reveal a molecular pathway that tightly regulates oxalate and citrate to guard against Ca²⁺-oxalate stone formation.     

Dynamic Three-Dimensional Ultrasound to Evaluate Scapular Movement Among Manual Wheelchair Users and Healthy Controls

Background:

A large percentage of individuals with spinal cord injury (SCI) report shoulder pain that can limit independence and quality of life. The pain is likely related to the demands placed on the shoulder by transfers and propulsion. Shoulder pathology has been linked to altered scapular mechanics; however, current methods to evaluate scapular movement are invasive, require ionizing radiation, are subject to skin-based motion artifacts, or require static postures.

Objective:

To investigate the feasibility of applying 3-dimensional ultrasound methods, previously used to look at scapular position in static postures, to evaluate dynamic scapular movement.

Method:

This study evaluated the feasibility of the novel application of a method combining 2-dimensional ultrasound and a motion capture system to determine 3-dimensional scapular position during dynamic arm elevation in the scapular plane with and without loading.

Results:

Incremental increases in scapular rotations were noted for extracted angles of 30°, 45°, 60°, and 75° of humeral elevation. Group differences were evaluated between a group of 16 manual wheelchair users (MWUs) and a group of age- and gender-matched able-bodied controls. MWUs had greater scapular external rotation and baseline pathology on clinical exam. MWUs also had greater anterior tilting, with this difference further accentuated during loading. The relationship between demographics and scapular positioning was also investigated, revealing that increased age, pathology on clinical exam, years since injury, and body mass index were correlated with scapular rotations associated with impingement (internal rotation, downward rotation, and anterior tilting).

Conclusion:

Individuals with SCI, as well as other populations who are susceptible to shoulder pathology, may benefit from the application of this imaging modality to quantitatively evaluate scapular positioning and effectively target therapeutic interventions.Key words: kinematics, scapula, ultrasound, wheelchair userThe shoulder is a common site of injury across many populations. Because it is the most mobile joint in the body, the high prevalence of disorders is not surprising. Individuals are at increased risk for shoulder pathology when exposed to high forces, sustained postures, and repetitive movements.¹ Wheelchair users are exposed to all of these factors in activities of daily living. Among manual wheelchair users (MWUs), 35% to 67% report shoulder pain.^2–7 In this population, the presence of shoulder dysfunction significantly affects function and decreases quality of life.^8,9 With altered scapular kinematics being linked to a multitude of shoulder problems, the identification of changes in kinematics may allow for earlier detection of pathology and targeting of appropriate interventions.^10–25 However, evaluation of dynamic scapular movement is a challenging task, as the scapula rotates about 3 axes while also gliding underneath overlying tissue. Direct visualization of the bone is ideal but is often limited by cost, availability, and exposure to radiation, and skin-based systems are prone to error.^26–33The overall goal of this study was to investigate the feasibility of applying 3-dimensional ultrasound methods, previously used to look at scapular position in static postures, to evaluate dynamic scapular movement.³⁴ The specific goals were as follows:

1. Evaluate intermediate angles of functional elevation during dynamic movement (30°, 45°, 60°, and 75°). We hypothesize that we will see incremental increases in external rotation, upward rotation, and posterior tipping throughout the movement to maintain the distance between the acromion and humerus.
2. Compare dynamic scapular movement between MWUs and able-bodied controls (ABs). We anticipate that the nature of wheelchair propulsion and demands of activities of daily living will elucidate differences between this population and ABs with comparably lower daily demands on the shoulder.
3. Evaluate the effect of loading on scapular movement, as other studies have suggested that differences in kinematics are clearer in the presence of loading.^10,35,36
4. Investigate the relationship between shoulder pathology, age, years since injury, and body mass index (BMI) and scapular positioning.

     

Initial experience with robotic-assisted laparoscopic radical prostatectomy in the Canadian health care system

Background:

Robotic-assisted laparoscopic radical prostatectomy (RALRP) has gained popularity in the United States due to claims of its superior 3-dimensional magnified vision and improved manual dexterity for surgeons that shorten the learning curve and facilitate the transition from standard open radical prostatectomy to laparoscopic prostatectomy as a minimally invasive procedure. The Canadian health care system, however, faces unique challenges when dealing with the introduction of new technologies. We report the initial experience with the use of the da Vinci robot for RALRP at the University of Western Ontario.

Methods:

We retrospectively reviewed the records of the initial 30 cases of RALRP with a minimum of 6 months follow-up. Data included the surgical times of various operative segments from cases 1–15 and 16–30, perioperative complications, early oncology and early functional results.

Results:

The lack of dedicated resources initially led to sporadic and infrequent cases. Nevertheless, there was improvement in surgical proficiency with significant difference in operative times between cases 1–15 and 16–30. Perioperative complications, though significant, were commensurate with reported early experiences from other centres worldwide, which reflects the learning curve with RALRP.

Conclusion:

Initiating a new surgical program that involves significant capital and maintenance costs, such as an RALRP program, within the Canadian health care system poses unique challenges for the surgical team. Nevertheless, our initial experience has encouraged us to proceed with the next phase of evaluation for the urological and oncological application of the technology.Laparoscopic radical prostatectomy, first described in the early 1990s,¹ was popularized by several European groups,^2–4 with the main impetus being to decrease operative morbidity while upholding principles of oncological therapy and theoretically minimizing long-term morbidity, such as incontinence and erectile dysfunction.Surgical robotics have improved laparoscopic surgical proficiency by:

• providing superior 3-dimensional “up close” magnification and an unparalleled view of the deep pelvis and retropubic space;
• facilitating surgical manipulation with superior dexterity via “wristed motions” and increased degrees of surgical freedom; and
• improving precision of dissection by tremor filtration and movement scaling.⁵

The pioneering efforts of some US centres using the da Vinci surgical robot (Intuitive Surgical, Sunnyvale, Calif.) have popularized robotic-assisted laparoscopic radical prostatectomy (RALRP),^5,6 reporting a significantly shortened learning curve for laparoscopic radical prostatectomy and facilitating the “transition” from open radical prostatectomy to RALRP.⁷Although several Canadian centres are routinely performing laparoscopic prostatectomy, with our health care budgetary constraints, only 2 centres in Canada are currently equipped with a da Vinci robot capable of performing RALRP. In contrast, with the US health care system and the marketing initiatives of various centres, there has been a proliferation of da Vinci robots in the United States, with an exponential increase in the number of RALRPs performed in the past few years. Despite the numerous reports suggesting the superiority of RALRP over open approaches, there has not been high-level evidence to support this contention. Our objective was to establish a RALRP program at the University of Western Ontario, with the initial step of conducting a technical feasibility study of 30 cases, possibly as a lead-in to a Phase III randomized study between RALRP and standard open radical retropubic prostatectomy for clinical localized prostate cancer. Herein, we report the first short-term Canadian experience with RALRP, and we examine the challenges of implementing this technology in Canada.     

Supracostal Approach for PCNL: Is 10th and 11th Intercostal Space Safe According to Clavien Classification System?

The purpose of this study was to evaluate the success and morbidity of percutaneous nephrolithotomy (PCNL) performed through the 11th and 10th intercostal space. Between March 2005 and February 2012, 612 patients underwent PCNL, 243 of whom had a supracostal access. The interspace between the 11th and 12th rib was used in 204 cases (group 1) and between the 10th and 11th interspaces in 39 cases (group 2). PCNL was performed using standard supracostal technique in all patients. The operative time, success rate, hospital stay, and complications according to the modified Clavien classification were compared between group 1 and group 2. The stone-free rate was 86.8% in group 1 and 84.6% in group 2 after one session of PCNL. Auxiliary procedures consisting of ureterorenoscopy (URS) and shock wave lithotripsy (SWL) were required in 5 and 7 patients, respectively, in group 1; and in 1 patient each in group 2 . After the auxiliary procedures, stone-free rates increased to 92.6% in group 1 and 89.7% in group 2. A total of 74 (30.4%) complications were documented in the 2 groups according to modified Clavien classification. Grade-I complications were recorded in 20 (8.2%), grade-II in 38 (15.6%), grade-IIIa in 13 (5.3%), and grade-IIIb in 2 (0.8%) patients; grade-IVa was recorded in 1 (0.4%) patient. There were no grade-IVb or grade-V complications. Overall complication rate was 30.9% in group 1 and 28.2% in group 2. Supracostal PCNL in selected cases is effective and safe with acceptable complications. The modified Clavien system provides a standardized grading system for complications of PCNL.Key words: Percutaneous nephrolithotomy, Supracostal approach complications, Clavien classification, Kidney stonePercutaneous nephrolithotomy (PCNL) is the accepted treatment for staghorn stones, large renal stones, and some upper ureteric stones.¹ Optimal and atraumatic access to the desired calix is a vital step in a successful PCNL. Stone site and burden or calyceal anatomy may necessitate the need for upper pole renal access via a supracostal approach.² The indications for the upper pole approach are staghorn calculi, multiple calculi in the superior and inferior calyceal groups, and renal pelvis, and large upper ureteral calculi and calculi in specific anatomy. An access through the superior calix provides a straight tract along the long axis of the kidney with optimal visualization of the collecting system, and it is associated with less torquing, less bleeding, and ultimately better clearance. The advantage of the superior calyceal approach in percutaneous renal surgery has been reported by many authors.^2–7 However, it is usually a concern because of the potential complications of pneumothorax, hydrothorax, pleural effusion, and lung injury.Although large-series PCNL results have been reported, there is still a lack of consensus on how to define complications and grade their severity. The Clavien classification system has been proposed to grade complications of general surgery.⁸ The classification has recently been modified and tested in a cohort of 6336 patients who underwent elective general surgery,⁹ it has also been studied by urologists for PCNL.^10–12 The modified Clavien classification system determines the severity of a complication by using a scale with 5 grades. Grade-I complications are designated as any deviations from the normal postoperative course that do not require extra therapy (with the exception of antiemetic, antipyretic, analgesic, and diuretic drugs). Grade-II complications necessitate pharmacologic treatment with drugs other than the drugs mentioned for the grade-I complications, as well as the need for blood transfusion or total parenteral nutrition. Grade-III complications are defined as complications necessitating surgical, endoscopic, or radiologic intervention. This grade is subdivided into grades IIIa and IIIb on the basis of the need for general anesthesia. Grade-IV complications are life threatening and necessitate intensive care, often leaving the patient with residual disability. This grade is subdivided into grade IVa and grade IVb owing to the number of affected organs. A grade-V complication represents the death of a patient as the result of the complication.⁹To the best of our knowledge, until now no study has evaluated perioperative complications of supracostal PCNL using the modified Clavien classification. For this reason, we retrospectively evaluated the patients who underwent PCNL by an intercostal approach (10th or 11th intercostal space) at our institute.     

Kidney Stones Associate with Increased Risk for Myocardial Infarction

Kidney stones are a risk factor for chronic kidney disease (CKD), which, in turn, is a risk factor for myocardial infarction (MI). The objective of this study was to determine whether kidney stones associate with an increased risk for MI. We matched 4564 stone formers (1984 through 2003) on age and gender with 10,860 control subjects among residents in Olmsted County, Minnesota. We identified incident MI by diagnostic codes and validated events by chart review through 2006. We used diagnostic codes to determine incidence of kidney stones and presence of comorbidities (CKD, hypertension, diabetes, obesity, dyslipidemia, gout, alcohol dependence, and tobacco use). During a mean of 9 years of follow-up, stone formers had a 38% (95% confidence interval 7 to 77%) increased risk for MI, which remained at 31% (95% confidence interval 2% to 69%) after adjustment for CKD and other comorbidities. In conclusion, kidney stone formers are at increased risk for MI, and this risk is independent of CKD and other risk factors.Kidney stones have been identified as a risk factor for chronic kidney disease (CKD).¹ Of great concern with the development of CKD is an increased risk for coronary heart disease. Reduction in both GFR and albuminuria is associated with coronary heart disease in the general population.^2,3 It was hypothesized that the increased risk for CKD in individuals with kidney stones would lead to an increased risk for coronary heart disease. Alternatively, biological pathways that cause calcium kidney stones may also contribute to coronary artery calcification, a risk factor for coronary heart disease events. Myocardial infarction (MI) surveillance in Olmsted County, Minnesota, has been in place since 1979.^4–7 We sought to determine whether kidney stone formers in Olmsted County were at an increased risk for MI and whether this risk is related to the development of CKD.A total of 5081 incident stone formers and 14,144 matched control subjects were identified from the Olmsted County general population between 1984 and 2003. The International Classification of Diseases, Ninth Revision (ICD-9) code used to identify stone formers was 592 (calculus of kidney and ureter) in 4467 (88%), 594 (calculus of lower urinary tract) in 613 (12%), and 274.11 (uric acid nephrolithiasis) in one (<1%). Prevalent MIs were similar between stone formers (n = 178 [3.5%]) and control subjects (n = 489 [3.5%]). After exclusion of individuals with prevalent MI and those who lacked clinic visits at least 90 days after the index date, 4564 stone formers and 10,860 control subjects were followed for incident MI. Only 2.1% of these individuals were nonwhite, consistent with the racial distribution of the community (96% white in 1990). As a consequence of the matching, stone formers and control subjects were similar with respect to age (mean 44.6 versus 44.4 year), gender (59 versus 58% male), length of medical record documentation before the index date (mean 18.4 versus 21.9 years), and length of follow-up to last clinic visit or death (mean 8.7 versus 9.0 years). As shown in

俯卧分腿位一期经皮肾镜联合输尿管软镜治疗复杂性铸型结石的临床研究

目的探讨俯卧分腿位一期经皮肾镜（PCNL）联合逆行输尿管软镜（RIRS）治疗复杂性铸型结石的可行性、有效性和安全性。 方法回顾性分析我院2015年8月至2019年8月93例复杂性铸型结石患者的临床资料,其中PCNL组50例仅行PCNL,PCNL+RIRS组43例一期行PCNL联合RIRS,术前肾结石情况采用S.T.O.N.E评分系统进行评估;两组均在截石位下置入输尿管支架管（剪去头端）,PCNL组改为俯卧位,PCNL+RIRS组改为俯卧分腿位,比较两组的手术时间、术后血红蛋白下降值、术后发热率、再次手术率、结石清除率、术后住院天数及并发症。 结果两组的术前基本资料差异无统计学意义,所有患者均顺利完成手术,PCNL+RIRS组需要建立的通道显著少于PCNL组;PCNL+RIRS组在血红蛋白下降值、结石清除率、再次手术率、平均住院天数上均明显优于PCNL组;虽然两组在手术时间、术后发热率、手术并发症差异无统计学意义,但是PCNL组有1例需要介入栓塞患者,并且PCNL组患者术后发热比例高于PCNL+RIRS组,差异无统计学意义可能与本研究例数较少有关。 结论俯卧分腿位一期经皮肾镜联合逆行输尿管软镜治疗复杂性肾结石安全有效,可以减少穿刺通道和术中出血,提高结石清除率,降低再次手术率。     

Progression to metastatic disease from a small renal cell carcinoma prospectively followed with an active surveillance protocol

With the widespread use of abdominal imaging to evaluate other medical conditions, many renal tumours are being diagnosed at earlier stages. Older patients have experienced the most significant increase in the incidence of renal cell carcinoma (RCC). This age group frequently has significant medical comorbidities. This has led to the concept of active surveillance for select patients with renal lesions that may not affect their mortality. However, the ultimate risk of active surveillance is the potential for developing metastases. This case report presents the development of metastatic disease from a small, incidentally detected and prospectively followed RCC with asymptomatic progression.The incidence of renal cell carcinoma (RCC) is rising. It accounts for 3% of all adult malignancies.¹ Patients aged 70–90 years have experienced the most significant increase.^2,3 This age group frequently has significant medical comorbidities. With the more common use of abdominal imaging to evaluate other medical conditions, many renal tumours are being diagnosed at earlier stages.² The presentation of RCC by incidental detection has increased from 10% to greater than 60% over the past 30 years.⁴ This has led to the concept of active surveillance for select patients with renal lesions that may not affect their mortality. The ultimate risk of active surveillance is, however, the potential for developing metastasis, at which point curative treatment is no longer an option. This case report presents a patient with a small RCC who developed metastatic disease while on active surveillance.     

Nonstented tubularized incised plate urethroplasty with Y-to-I spongioplasty in non–toilet trained children

Introduction

This study was designed to evaluate the supportive role of spongioplasty during tubularized incised plate (TIP) urethroplasty repair of hypospadias.

Methods

All non–toilet trained children who underwent TIP repair for primary hypospadias by 1 surgeon over a 30-month period were included in our study. The divergent spongiosa was mobilized off the corpora cavernosa and was rotated toward the midline to wrap the neourethra. A dartos flap was used to cover the neourethra. The neourethra was calibrated immediately after surgery in all patients. A urethral stent was left in place only when difficult calibration was encountered. Complications and cosmetic appearance were documented at last follow-up.

Results

Thirty-two consecutive patients with a mean age of 18 (standard deviation [SD] 6) months were included in the study. The defects were distal and mid-shaft in 26 patients (81.3%) and proximal-shaft in 6 (18.8%). No intraoperative catheterization difficulties were encountered and all repairs were nonstented. Antibiotics and anticholinergics were not required. Mean follow-up was 9 (SD 6) months. Urinary extravasation developed in 1 patient (3.1%) on the second postoperative day. A urethral catheter was easily inserted and left indwelling for 5 days. One patient presented 6 days postoperatively with suspected voiding difficulty. Urethral calibration was easily performed excluding any mechanical obstruction. There were no urinary fistulae and reoperation was not required. An excellent cosmetic appearance was achieved in all patients.

Conclusion

TIP urethroplasty is a versatile operation that can be performed in almost all cases of penile hypospadias. A nonstented technique for hypospadias repair simplifies postoperative care and obviates the need for antibiotics and anticholinergics. We believe that spongioplasty provides good support to the neourethra and the hypoplastic distal urethra that may facilitate catheterization in the immediate and early postoperative periods, if required. Future controlled study is warranted to further evaluate the role of spongioplasty.Several authors have reported excellent results with a stent-free tubularized incised plate (TIP) urethroplasty repair without an increase in the complication rate.^1,2,2,4 However, early postoperative urinary retention occurs in 2%–24% of patients.^3,5,6 In such cases, urethral catheterization is discouraged, as it is believed to increase the risk of fistula formation. Suprapubic catheter placement has been recommended as the preferred treatment.³ This may necessitate another anesthetic and may add the risk of hematuria secondary to inadvertent bladder mucosal injury. The risk of urinary retention has led some surgeons to continue using stents during TIP repairs.Y-to-I wrap spongioplasty has been shown to recreate a nearly normal urethra in most cases.⁷ We hypothesized that spongioplasty can provide sufficient urethral support to withstand early urethral catheterization without compromising the repair. This study was designed to evaluate the supportive role of spongioplasty during TIP repair for various degrees of penile hypospadias.     

Lower pole stones: prone PCNL versus supine PCNL in the International Cooperation in Endourology (ICE) group experience

Purpose

To assess efficacy and safety of prone- and supine percutaneous nephrolithotomy (PCNL) for the treatment of lower pole kidney stones.

Methods

Data from patients affected by lower pole kidney stones and treated with PCNL between December 2005 and August 2010 were collected retrospectively by seven referral centres. Variables analysed included patient demographics, clinical and surgical characteristics, stone-free rates (SFR) and complications. Statistical analysis was conducted to compare the differences for SFRs and complication rates between prone- and supine PCNL.

Results

One hundred seventeen patients underwent PCNL (mean stone size: 19.5 mm) for stones harboured only in the lower renal pole (single stone: 53.6 %; multiple stones: 46.4 %). A higher proportion of patients with ASA score ≥ 3 and harbouring multiple lower pole stones were treated with supine PCNL (5.8 vs. 23.1 %; p = 0.0001, and 25 vs. 81.5 %; p = 0.0001, respectively, for prone- and supine PCNL). One-month SFR was 88.9 %; an auxiliary procedure was needed in 6 patients; the 3-month SFR was 90.2 %. There were 9 post-operative major complications (7.7 %). No differences were observed in terms of 1- and 3-month SFRs (90.4 vs. 87.7 %; p = 0.64; 92.3 vs. 89.2 %; p = 0.4) and complication rates (7.6 vs. 7.7 %; p = 0.83) when comparing prone- versus supine PCNL, respectively.

Conclusions

The results confirm the high success rate and relatively low morbidity of modern PCNL for lower pole stones, regardless the position used. Supine PCNL was more frequently offered in case of patients at higher ASA score and in case of multiple lower pole stones.     

Mechanisms of control of the free Ca2+ concentration in the endoplasmic reticulum of mouse pancreatic β-cells: interplay with cell metabolism and [Ca2+]c and role of SERCA2b and SERCA3

OBJECTIVE

Sarco-endoplasmic reticulum Ca²⁺-ATPase 2b (SERCA2b) and SERCA3 pump Ca²⁺ in the endoplasmic reticulum (ER) of pancreatic β-cells. We studied their role in the control of the free ER Ca²⁺ concentration ([Ca²⁺]_ER) and the role of SERCA3 in the control of insulin secretion and ER stress.

RESEARCH DESIGN AND METHODS

β-Cell [Ca²⁺]_ER of SERCA3^+/+ and SERCA3^−/− mice was monitored with an adenovirus encoding the low Ca²⁺-affinity sensor D4 addressed to the ER (D4ER) under the control of the insulin promoter. Free cytosolic Ca²⁺ concentration ([Ca²⁺]_c) and [Ca²⁺]_ER were simultaneously recorded. Insulin secretion and mRNA levels of ER stress genes were studied.

RESULTS

Glucose elicited synchronized [Ca²⁺]_ER and [Ca²⁺]_c oscillations. [Ca²⁺]_ER oscillations were smaller in SERCA3^−/− than in SERCA3^+/+ β-cells. Stimulating cell metabolism with various [glucose] in the presence of diazoxide induced a similar dose-dependent [Ca²⁺]_ER rise in SERCA3^+/+ and SERCA3^−/− β-cells. In a Ca²⁺-free medium, glucose moderately raised [Ca²⁺]_ER from a highly buffered cytosolic Ca²⁺ pool. Increasing [Ca²⁺]_c with high [K] elicited a [Ca²⁺]_ER rise that was larger but more transient in SERCA3^+/+ than SERCA3^−/− β-cells because of the activation of a Ca²⁺ release from the ER in SERCA3^+/+ β-cells. Glucose-induced insulin release was larger in SERCA3^−/− than SERCA3^+/+ islets. SERCA3 ablation did not induce ER stress.

CONCLUSIONS

[Ca²⁺]_c and [Ca²⁺]_ER oscillate in phase in response to glucose. Upon [Ca²⁺]_c increase, Ca²⁺ is taken up by SERCA2b and SERCA3. Strong Ca²⁺ influx triggers a Ca²⁺ release from the ER that depends on SERCA3. SERCA3 deficiency neither impairs Ca²⁺ uptake by the ER upon cell metabolism acceleration and insulin release nor induces ER stress.Pancreatic β-cells stimulated by glucose display oscillations of the free cytosolic Ca²⁺ concentration ([Ca²⁺]_c) resulting from intermittent Ca²⁺ influx (1,2). Their endoplasmic reticulum (ER) takes up cytosolic Ca²⁺ by two sarco-endoplasmic reticulum Ca²⁺-ATPases (SERCAs): SERCA2b, ubiquitously expressed, and SERCA3, expressed only in islet β-cells (3,4). The role played by the ER in the [Ca²⁺]_c response to glucose is unclear. In particular, it has been suggested that Ca²⁺ influx through voltage-dependent Ca²⁺ channels facilitates the uptake of Ca²⁺ by the ER (5–10) or, on the contrary, triggers a release of Ca²⁺ from the ER (11–14), which might contribute to glucose-induced [Ca²⁺]_c oscillations (11,14) or to a sustained and pronounced [Ca²⁺]_c rise (12,13).The method of choice to monitor the free ER Ca²⁺ concentration ([Ca²⁺]_ER) in living cells uses genetically encoded, Ca²⁺-sensitive probes targeted to the organelle (15,16). One of them, D1ER, a ratiometric Ca²⁺ indicator, has been used in several cell types (17,18). However, the D1 Ca²⁺ sensor has a relatively high affinity for Ca²⁺ (60 µmol/L) (19). To yield a more suitable probe to monitor higher [Ca²⁺]_ER, we replaced D1 by D4 that has a lower affinity for Ca²⁺ (195 µmol/L) (20), and expressed it under the control of the insulin promoter in clusters of β-cells. In most experiments, [Ca²⁺]_ER (D4ER) and [Ca²⁺]_c (FuraPE3) were simultaneously recorded to evaluate the interplay between both parameters. Because SERCA2b and SERCA3 have been suggested to play distinct roles (4,5), we evaluated their respective roles on [Ca²⁺]_c and [Ca²⁺]_ER by using β-cells from wild-type (SERCA3^+/+, expressing SERCA2b and SERCA3) and SERCA3 knockout mice (SERCA3^−/−, expressing SERCA2b only) (21). We also assessed the role of SERCA3 in glucose tolerance, insulin secretion, and ER stress, as it was found that missense mutations of the human SERCA3 gene are associated with type 2 diabetes (22), SERCA3 expression is reduced in diabetic rat models (23), and SERCA3 is involved in ER stress (24).     

俯卧分腿位经皮肾镜碎石取石术治疗肾结石

目的分析俯卧分腿位在经皮肾镜碎石取石术（PCNL）治疗肾结石中的可行性、有效性和安全性。 方法选择2016年1月至2017年5月于我院接受治疗的360例肾结石患者,其中观察组189例行俯卧分腿位PCNL,对照组171例行传统俯卧位PCNL。观察组在俯卧分腿位下行患侧输尿管逆行插管建立人工肾积水,在超声定位下建立16~24 F经皮肾工作通道,从皮肾通道置入肾镜或输尿管镜,行碎石取石术。对照组采用截石位逆行插管建立人工肾积水,再变换为俯卧位,后续手术方法同前。记录建立通道时间、手术时间、术中出血量和住院时间等资料,通过Clavien-Dindo分级系统比较围手术期并发症,统计S.T.O.N.E结石评分、结石清除率和再次手术率等数据。 结果两组手术均顺利实施,观察组手术时间、建立通道时间、术中出血量、住院天数和再次手术率均低于对照组,对比差异有统计学意义（P<0.05）。结石取尽率、S.T.O.N.E结石评分和输血率两组对比差异无统计学意义（P>0.05）。Clavien-Dindo并发症分级系统中,Ⅰ、Ⅱ、Ⅲb两组对比差异无统计学意义（P>0.05）。 结论在肾结石患者的治疗中,使用俯卧分腿位PCNL安全可行,减少了手术时间、术中出血量,并降低了再次手术率,提高了手术的安全性和有效性。     

Endoscopic Combined Intrarenal Surgery in Galdakao-Modified Supine Valdivia Position: A New Standard for Percutaneous Nephrolithotomy?

Background

Percutaneous nephrolithotomy (PCNL), the gold standard for the management of large and/or complex urolithiasis, is conventionally performed with the patient in the prone position, which has several drawbacks. Of the various changes in patient positioning proposed over the years, the Galdakao-modified supine Valdivia (GMSV) position seems the most beneficial. It allows simultaneous performance of PCNL and retrograde ureteroscopy (ECIRS, Endoscopic Combined Intra-Renal Surgery) and has unquestionable anaesthesiological advantages.

Objective

To prospectively analyse the safety and efficacy of endoscopic combined intrarenal surgery (ECIRS) in GMSV position for the treatment of large and/or complex urolithiasis.

Design, setting, and participants

From April 2004 to December 2007, 127 consecutive patients who were followed in our department for large and/or complex urolithiasis were selected for surgery (American Society of Anesthesiologists [ASA] score 1–3, no active urinary tract infection [UTI], any body mass index [BMI]).

Intervention

All the patients underwent ECIRS in GMSV position. Technical choices about percutaneous access, endoscopic instruments and accessories, and postoperative renal and ureteral drainage are detailed.

Measurements

Patients’ mean age plus or minus standard deviation (± SD) was 53.1 yr ± 14.2. Of the 127 patients, 5.5% had congenital renal abnormalities, 3.9% had solitary kidneys, and 60.6% were symptomatic for renal colics, haematuria, and recurrent UTI. Mean stone size ± SD was 23.8 mm ± 7.3 (range: 11–40); 33.8% of the calculi were calyceal, 33.1% were pelvic, 33.1% were multiple or staghorn, and 4.7% were also ureteral.

Results and limitations

Mean operative time ± SD was 70 min ± 28, including patient positioning. Stone-free rate was 81.9% after the first treatment and was 87.4% after a second early treatment using the same percutaneous access during the same hospital stay (mean ± SD: 5.1 d ± 2.9). We registered overall complications at 38.6% with no splanchnic injuries or deaths and no perioperative anaesthesiological problems.

Conclusions

ECIRS performed in GMSV position seems to be a safe, effective, and versatile procedure with a high one-step stone-free rate, unquestionable anaesthesiological advantages, and no additional procedure-related complications.