Bradley F. Schwartz

The vesical calculus.

Bladder calculi account for 5% of urinary calculi and usually occur because of foreign bodies, obstruction, or infection. Males with prostate disease or previous prostate surgery and women who undergo anti-incontinence surgery are at higher risk for developing bladder calculi. Patients with SCI with indwelling Foley catheters are at high risk for developing stones. There appears to be a significant association between bladder calculi and the formation of malignant bladder tumors in these patients. Transplant recipients are not at increased risk for developing vesical calculi in the absence of intravesical suture fragments and other foreign bodies. Patients who undergo bladder-augmentation procedures using a vascularized gastric patch appear to be protected from vesicolithiasis, perhaps by the acidic environment. Ileum and colon tissues, however, are colonized by urease-producing organisms, producing an alkaline pH that promotes stone formation. Children remain at high risk for bladder-stone development in endemic areas. Diet, voiding dysfunction, and uncorrected anatomic abnormalities, such as posterior urethral valves and vesicoureteral reflux, predispose them to bladder-calculus formation. Finally, there are a number of techniques and modalities available to remove bladder stones. Relieving obstruction, eliminating infection, meticulous surgical technique, and accurate diagnosis are essential in their treatment.

IMAGING CHARACTERISTICS OF INDINAVIR CALCULI

PURPOSE Indinavir sulfate is an effective protease inhibitor of the human immunodeficiency virus type 1. Use is associated with a significant incidence of crystallization and stone formation in the urinary tract, and these calculi are not visible on plain radiographs. Previously all urinary stones, including uric acid and matrix, were believed to be radiodense on computerized tomography (CT). We conducted a retrospective study to evaluate the radiographic appearance of indinavir calculi. MATERIALS AND METHODS Retrospective chart review of 36 patients taking indinavir sulfate and presenting with renal colic was performed with attention to presentation, urinalysis, radiographic evaluation and management. Specifically, imaging characteristics on CT were addressed. RESULTS All patients complained of ipsilateral flank pain and 35 had nausea and/or vomiting. Of 30 patients with dysuria or urgency the majority had hematuria, and most had pyuria and/or proteinuria. No stones were visualized on abdominal radiography. Diagnosis was confirmed on 1 of 13 excretory urograms and 4 of 11 renal ultrasounds. None of 12 CT scans was diagnostic of renal lithiasis. CONCLUSIONS Indinavir sulfate is a protease inhibitor with poor solubility and significant urinary excretion. Crystallization and stone formation are demonstrated in as many as 20% of patients taking the medication. Most patients present with flank pain, nausea or vomiting and hematuria. Previously CT was thought to identify all urinary calculi with clarity but it cannot reliably confirm the presence of indinavir calculi.

Robot-Assisted Laparoscopic Sacrocolpopexy as Management for Pelvic Organ Prolapse

BACKGROUND AND PURPOSE Robot-assisted laparoscopic sacrocolpopexy (RALS) is a new surgical management option for pelvic organ prolapse that secures the apex of the vagina to the sacral promontory. Limited literature exists on outcomes of this procedure. We present our initial experience with RALS. PATIENTS AND METHODS Women with vaginal vault prolapse and significant apical defects as defined by a Baden-Walker score of 3 or greater were offered RALS without any other procedure. Chart review was performed to analyze operative and perioperative data, including urodynamics (UDS) and Baden-Walker classification before and after surgery. Data were analyzed with comparison of presurgical and postsurgical data. RESULTS From July 2005 through July 2007, 21 patients underwent RALS. Blood loss was negligible. Average operative time, including robot docking, was 3 hours, 14 minutes. Nineteen patients were discharged on postoperative day 1. UDS were not changed significantly. One patient had an apical recurrence. There were no operative complications or conversions; however, one patient had a small bowel obstruction 5 days after surgery necessitating laparotomy. Of the 21 patients, 12 have undergone anterior and posterior repair, 5 await repair, and 4 patients have opted for conservative management. CONCLUSIONS RALS is effective to repair apical vaginal defects in patients with significant pelvic organ prolapse. Operative time is manageable and complications are few. Cystocele, rectocele, and UDS remain essentially unchanged by RALS. Most, if not all, patients with cystocele and rectocele will need further vaginal reconstruction after RALS, if desired. Greater follow-up and numbers are needed to further establish the role of this procedure.

Effect of percutaneous nephrolithotomy on differential renal function as measured by mercaptoacetyl triglycine nuclear renography

OBJECTIVES To determine the impact on differential renal function of percutaneous nephrolithotomy for complex renal calculi. METHODS From July 1999 to December 2000, 45 patients underwent percutaneous nephrolithotomy. Of these, 19 agreed to participate in the study. All patients completed a quantitative assessment of differential renal function preoperatively and postoperatively with technetium 99m mercaptoacetyl triglycine nuclear renography and serum creatinine measurements. RESULTS The mean patient age was 49 years (range 11 to 75) for the 13 female and 6 male patients. The mean stone burden was 1432 mm(2) (range 156 to 5220). The mean surgical time was 2.57 hours (range 1.17 to 5.08). The median hospital stay was 2.0 days (range 1 to 19). Of the 19 patients, 13 (68%) were stone free after one procedure. Four patients underwent ureteroscopy with stone extraction for residual fragments. One patient underwent secondary extracorporeal shock wave lithotripsy. One patient underwent nephrectomy for poor renal function. Renal function, for the entire group, increased from 36.8% preoperatively to 38.5% postoperatively. Renal function was preserved in 16 (84%) of 19 patients, including improvement of function in 7 (37%) of 19 patients. Serum creatinine was unchanged in the two groups. CONCLUSIONS Percutaneous nephrolithotomy does not result in loss of renal function when treating complex renal calculi as measured by nuclear scintigraphy. Operative and hospitalization times were decreased compared with historical open nephrolithotomy and stone clearance was similar.

Metal Ureteral Stent for Benign and Malignant Ureteral Obstruction

PURPOSE Metal ureteral stents are a relatively new version of a device with a long history of relieving ureteral obstruction. Metal stents are effective for relieving ureteral obstruction but success regarding patient tolerability has been variable. We present our single institution experience with long-term metal ureteral stent placement. MATERIALS AND METHODS The charts of patients undergoing metal ureteral stent placement for chronic ureteral obstruction were reviewed. Data collected included patient age, gender, diagnosis/cause of obstruction, laterality, duration of indwelling metal stent, number of routine metal stent changes, complications and early discontinuations or stent changes. RESULTS A total of 23 patients underwent placement of metal ureteral stents between February 2008 and September 2010. Bilateral stents were placed in 5 patients and 9 underwent a yearly metal stent exchange for a total of 42 ureteral units treated with metal ureteral stents. All metal stents were placed to relieve ureteral obstruction due to ureteral stricture, ureteropelvic junction obstruction, retroperitoneal fibrosis or extrinsic malignant obstruction. There were 3 metal stent failures in 2 patients with malignant ureteral obstruction. There were no complications, or early discontinuations or changes due to adverse symptoms, patient dissatisfaction, worsening renal function or progressive hydronephrosis. CONCLUSIONS Metal ureteral stents are effective for benign and malignant ureteral obstruction in the absence of urolithiasis. Good tolerability and annual stent exchange make metal stents an appealing alternative for patients with chronic ureteral obstruction treated with indwelling ureteral stents.

Calcium nephrolithiasis: effect of water hardness on urinary electrolytes

OBJECTIVES To analyze the impact of water hardness from public water supplies on calcium stone incidence and 24-hour urine chemistries in patients with known calcium urinary stone formation. Patients are frequently concerned that their public water supply may contribute to urinary stone disease. Investigators have documented an inverse relationship between water hardness and calcium lithogenesis. Others have found no such association. METHODS Patients who form calcium stones (n = 4833) were identified geographically by their zip code. Water hardness information from distinct geographic public water supplies was obtained, and patient 24-hour urine chemistries were evaluated. Drinking water hardness was divided into decile rankings on the basis of the public water supply information obtained from the Environmental Protection Agency. These data were compared with patient questionnaires and 24-hour urine chemistries. The calcium and magnesium levels in the drinking water were analyzed as independent variables. RESULTS The number of total lifetime stone episodes was similar between patients residing in areas with soft public water and hard public water. Patients consuming the softest water decile formed 3.4 lifetime stones and those who consumed the hardest water developed 3.0 lifetime stones (P = 0.0017). The 24-hour urine calcium, magnesium, and citrate levels increased directly with drinking water hardness, and no significant change was found in urinary oxalate, uric acid, pH, or volume. CONCLUSIONS The impact of water hardness on urinary stone formation remains unclear, despite a weak correlation between water hardness and urinary calcium, magnesium, and citrate excretion. Tap water, however, can change urinary electrolytes in patients who form calcium stones.

The Use of Internal Stents in Chronic Ureteral Obstruction

PURPOSE Despite the lack of a well delineated definition, chronic ureteral obstruction imposes significant quality of life loss, increased pathological morbidity and risk of mortality as well as substantial economic burden. Ureteral stenting serves as an important therapeutic option to alleviate obstruction. Thus, we assessed the recently published literature on chronic ureteral obstruction; treatment options; types, benefits and shortcomings of current ureteral stents; as well as outcomes and complications of chronic ureteral stenting, with the goal of providing concise management guidelines. MATERIALS AND METHODS A systemic literature review was performed on Embase™, PubMed®, Cochrane Controlled Trials Register and Google Scholar™ on ureteral obstruction and internal ureteral stents. Relevant reviews, original research articles and their cited references were examined, and a synopsis of original data was generated on a clinically oriented basis. RESULTS Chronic ureteral obstruction can be classified into compression that is either intrinsic or extrinsic to the ureteral wall, or obstruction that is of a benign or malignant origin. Patients with malignant ureteral obstruction generally have a poor prognosis and are often difficult to treat. The aim of stenting is to adequately drain the upper urinary tracts while minimizing hospitalization and the negative impact on quality of life. Facing the challenge of chronic ureteral obstruction, novel stents with new compositions, materials, coatings and designs have been developed. Metallic stents are emerging as efficacious and financially viable alternatives. Early stent related complications include iatrogenic injury, stent migration or patient discomfort, while late complications include infection, difficulties with stent exchange, hardware malfunction, infection and stent encrustation. CONCLUSIONS Stenting in chronic ureteral obstruction is a complex and challenging problem. Much work is being done in this area and many options are being explored.

COMPLICATIONS OF RETROGRADE BALLOON CAUTERY ENDOPYELOTOMY

PURPOSE Adult ureteropelvic junction obstruction is increasingly managed with endoscopic techniques. Retrograde balloon cautery endopyelotomy is quick, requires minimal hospital stay and allows most patients a rapid return to work. The complication rate of retrograde balloon cautery endopyelotomy ranges from 13 to 34%, with vascular injury in 0 to 16% of patients. We report 5 uncommon complications, including 4 vascular injuries, that clinicians should be familiar with when using this technique. MATERIALS AND METHODS We reviewed 52 retrograde endoscopic endopyelotomy procedures performed during a 5-year period. There were 5 uncommon complications. RESULTS Accessory lower pole renal artery injuries occurred in 3 patients, 1 of whom presented 12 days after endopyelotomy. Embolization was successfully performed in all 3 cases and none had subsequent hypertension. In 1 case a right ovarian vein laceration was not evident on preoperative or postoperative angiography. Emergency post-embolization abdominal exploration revealed a 2 mm. injury to the right ovarian vein before entering the right renal vein close to the ureteropelvic junction incision. Nephrectomy and ovarian vein ligature were curative. In 1 case the electrocautery wire broke intracorporeally after firing, resulting in a bobby pin-like configuration. Successful removal was accomplished by twisting the catheter and wrapping the wire around the tip, enabling atraumatic removal. CONCLUSIONS Retrograde balloon cautery endopyelotomy is an emerging technology with potential adverse outcomes. The complications we noted are complex and potentially life threatening. Awareness of these complications may help avoid poor outcomes and expedite appropriate treatment.

Rethinking the role of urinary magnesium in calcium urolithiasis

BACKGROUND AND PURPOSE The role of magnesium in urinary stone formation remains undefined. In vivo, magnesium inhibits stone formation in hyperoxaluric rats, and small clinical studies suggest a protective effect of magnesium supplementation in calcium oxalate stone formers. We performed a retrospective review of more than 7,000 stone patients to see if there is a relation between urinary magnesium and other stone risk variable constituents. MATERIALS AND METHODS A national database of stone formers categorized by residential ZIP code was queried, and, using strict inclusion criteria, 2,147 patients having pure calcium oxalate stones were identified. There were 1,912 (89%) eumagnesuric (43-246 mg/24 hours) and 235 (11%) hypomagnesuric (<43 mg/24 hours) patients. RESULTS Patients with decreased urinary magnesium excretion had significantly less daily urine excretion of citrate, calcium, oxalate, uric acid, and sodium than the eumagnesuric group (p < 0.0001). Stone recurrence was slightly more common in the hypomagnesuric group, although the difference was not statistically significant. The percentage of patients voiding <1 L of urine per day was significantly higher in the hypomagnesuric group. In the eumagnesuric group, males outnumbered females 2:1, whereas hypomagnesuric patients showed a female predominance of 1.4:1. CONCLUSION The beneficial effects of urinary magnesium on stone formation may be less than previously reported. The role of oral magnesium supplementation and the subsequent increase in urinary magnesium in calcium urinary stone formation remains unknown. Our data suggest that its effect on or interaction with citrate may be influential on urinary citrate concentrations. If magnesium has a protective effect, it may work through pathways that enhance citrate excretion.

Supracervical Robotic-Assisted Laparoscopic Sacrocolpopexy for Pelvic Organ Prolapse

Supracervical robotic-assisted laparoscopic sacrocolpopexy was found to be an effective repair of apical vaginal defects in patients with pelvic organ prolapse who had not undergone previous hysterectomy.