Laparoscopic nephrectomy for inflammatory renal conditions.

PURPOSE: Inflammatory and infectious renal conditions may result in severe perirenal fibrosis, making the laparoscopic approach challenging. The theoretical advantages of laparoscopy for managing inflammatory and infectious renal conditions have been questioned. We identified whether laparoscopy for inflammatory renal conditions is associated with higher morbidity than for other benign renal conditions. Furthermore, several technical modifications are discussed that may help to improve the outcome. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients who underwent laparoscopic nephrectomy for inflammatory and infectious renal conditions between 1998 and 2000. The transperitoneal approach was used and specimens were removed after morcellation. Operative data were compared with those from a similar group of patients who underwent laparoscopic nephrectomy for other benign conditions. RESULTS: Laparoscopic nephrectomy done for inflammatory or infectious conditions in 12 cases and for other benign conditions in 9 matched cases was completed successfully in 10 (83%) and 9 (100%), respectively. In the inflammatory and benign groups mean blood loss plus or minus standard deviation was 155 +/- 163 and 59 +/- 23 ml. (p = 0.099), mean operative time was 284 +/- 126 and 226 +/- 62 minutes (p = 0.225), and mean postoperative hospital stay was 4.1 +/- 2 and 3 +/- 1 days (p = 0.157), respectively. CONCLUSIONS: Laparoscopic nephrectomy can be performed safely in most cases of inflammatory renal conditions. Although they were not statistically significant, a higher conversion rate and longer operative time should be expected. Early conversion may be required due to failure to progress. Similar advantages were observed in patients with inflammatory and other benign renal conditions via the laparoscopic approach.

Novel method of assessing surgical margin status in laparoscopic specimens.

OBJECTIVES: To develop a novel method of inking laparoscopic specimens before piecemeal extraction to evaluate the surgical margins. METHODS: Methylene blue, indigo carmine, and India ink were tested in vitro on cadaveric bovine kidneys before manual morcellation in laparoscopic retrieval bags, and subsequently in pigs in vivo undergoing laparoscopic nephrectomy. Tissue fragments were examined both grossly and microscopically after routine histologic processing. On the basis of the findings in these experiments, we used India ink clinically in 4 cases of laparoscopic nephrectomy and adrenalectomy for suspected tumor and assessed the ability to indicate specimen margins grossly and microscopically. RESULTS: Methylene blue and India ink were the substances that best covered the surface of the surgical specimen completely, were best retained on the tissue, and were most easily washed from the retrieval bag. Gross inspection of the morcellated specimens easily distinguished the inked pieces, signifying tissue present at the surgical margin, from the uninked pieces. During morcellation, neither contamination of central tissue with ink nor leakage of ink from the bag occurred. India ink consistently endured fixation, embedding, and sectioning, with the black, inked margins of the specimen visible microscopically. CONCLUSIONS: Application of India ink before laparoscopic organ morcellation specifically marks the margins of the specimen. This technique allows pathologic determination of the surgical margin status, as well as fractionation of the tissue fragments, and addresses a criticism of organ morcellation. These improvements in the pathologic analysis of laparoscopically excised specimens may obviate the need for intact organ removal.

Radially expanding laparoscopic access for renal/adrenal surgery.

OBJECTIVES: To use a radially expanding system (Step) and a modified port location for intra-abdominal access to decrease the access-related complications in renal and adrenal surgery. Access-related complications during laparoscopic renal surgery are frustrating and are more common in patients with previous abdominal surgery and associated adhesions. METHODS: Laparoscopic upper tract procedures were performed in 62 patients using radially expanding trocars, and the results were reviewed with regard to access, port placement, and associated complications. For initial access, a Veress needle was placed subcostally in the midclavicular line. An expandable mesh sleeve trocar was used for trocar insertion after a pneumoperitoneum was established. A blunt-tipped fascial dilator was used to dilate to 10 or 12 mm. Additional ports were placed in an L shape (nephrectomy) or a subcostal configuration (adrenalectomy) under direct vision using the Step ports. RESULTS: Of 62 patients, 24 had had prior abdominal surgery. Open insertion of the mesh sleeve was necessary in 20%, of whom 60% had had prior abdominal surgery. In 9% of cases, the liver was punctured with the initial pass of the Veress needle. Only minimal bleeding from the injury site was noticed. The liver punctures did not require cauterization and did not result in conversion to an open procedure. At a mean follow-up of 12 months, no access-related complications or port-site hernias were noted. CONCLUSIONS: Placement of the initial access subcostally at the level of the midclavicular line helps to prevent visceral injury, especially in patients with previous abdominal surgery. The use of the radially expanding access system with the modification of port location allows safe and rapid laparoscopic access for upper urinary tract surgery. This trocar system is an excellent alternative to the standard laparoscopic trocars.

Radially expanding single-step nephrostomy tract dilator.

OBJECTIVES: To compare the radial and axial forces produced by balloon, Amplatz, and radially expanding single-step nephrostomy (RESN) systems and report our initial clinical results using the new RESN device. Balloon, Amplatz, and Alken dilators are commonly used to establish nephrostomy tracts in percutaneous surgery. They require multiple steps, with the potential for kinking and displacement of the working guidewire. In contrast, the new RESN tract dilator expands a unique sleeve conduit and places an Amplatz-like sheath in a single step with less dependence on a guidewire for dilation. METHODS: An experimental model was designed using a perforated silicon disc with a 10F central opening to measure the axial force transmission as 30F balloon, Amplatz, and RESN systems were inserted through the silicon discs. We also report our first 9 patients who underwent percutaneous dilation with the RESN system. RESULTS: Thirty French expansion was achieved with each dilator tested. Substantially lower axial forces were transmitted with the RESN device compared with the balloon and Amplatz dilators (5.2 versus 13.1 and 19.2 lb, respectively, P <0.001). Intraoperatively, all 9 patients were successfully dilated, and the kidney was relatively stationary as imaged with fluoroscopy. One patient with multiple prior renal procedures was successfully dilated with RESN system after failed attempts with balloon dilation. CONCLUSIONS: The RESN dilator is a rapid, single-step access system successfully used in our first 9 patients. Intraluminal sleeve dilation eliminates guidewire dependence for maintaining access, limits renal displacement, and facilitates appropriate vector force for percutaneous dilation.

Kidney morcellation in laparoscopic nephrectomy for tumor: recommendations for specimen sampling and pathologic tumor staging.

Laparoscopic nephrectomy is a novel approach for small renal tumors in selected patients; however, removal of the kidney through the small laparoscopic abdominal wall incision site requires the kidney to be morcellated into small fragments while still in situ. Morcellation presents two problems for the pathologist. First, guidelines for optimal sampling of morcellated fragments have not been described. Second, morcellation precludes complete pTNM tumor staging, in particular, tumor size, margins, and renal vein involvement. Based on our initial experience with 23 laparoscopic nephrectomies/nephroureterectomies (13 clinically suspected neoplasms, confirmed pathologically as renal cell carcinoma [RCC, n = 7], urothelial carcinoma of the renal pelvis [n = 3], angiomyolipoma [n = 1], and cystic nephroma [n = 1], and 10 clinically benign entities) and a conservative statistical model, we present a decision analysis model of various specimen sampling protocols that optimize cost, labor, or time to diagnosis (single vs sequential sampling). Using the tumor-to-kidney volume ratio (TKR), calculated from preoperative radiologic imaging and specimen gross weight, several specimen sampling algorithms were compared. For the average situation in which TKR is > or =0.15, the algorithm that most significantly optimizes cost and labor is one that initially samples 5% of the morcellated specimen. However, additional sampling may be required in one fourth of the cases. The optimal amount of sampled tissue may indeed be less than 5% because this assumes no suspicious tissue is grossly visible and in all our cases of RCC grossly visible tumor was identified. Additional nomograms for a spectrum of TKR, sampling success, and cost are presented to allow pathologists their own discretion in determining optimal sampling of the morcellated kidney. Tumor staging is severely limited by morcellation. Tumor size, renal capsule involvement, and renal vein involvement cannot be fully pathologically evaluated for RCC, whereas invasion cannot be definitively assessed for urothelial carcinoma of the renal pelvis. Knowledge of the radiologic features (lesion size, capsule, and vein involvement) is important in sampling and staging morcellated kidneys removed laparoscopically.

Treatment of refractory kidney transplant ureteral strictures using balloon cautery endoureterotomy.

OBJECTIVES: To report our long-term clinical results with the use of endoureterotomy in patients undergoing renal transplant with a minimum follow-up of 23 months. METHODS: Six renal transplant patients developed persistent ureteral obstruction demonstrated by elevated serum creatinine levels, renal ultrasound, and antegrade pyelography. Stent placement and balloon dilation were performed as the initial therapy in all patients. Persistent ureteral obstruction was managed with balloon cautery endoureterotomy. Ureteral stents were removed cystoscopically 6 weeks after the procedure. RESULTS: Four men and 2 women, mean age 45 years (range 38 to 54), underwent eight procedures: six by way of an antegrade percutaneous approach and two in an endoscopic retrograde fashion. The sites of ureteral stricture were ureterovesical junction (n = 4), ureteropelvic junction (n = 1), and midureteroureteral (n = 1). Two patients required a second endoureterotomy 3 months after the first attempt. Patients were followed up for a mean of 27 months (range 23 to 34). The mean serum creatinine level for all patients at follow-up was 2.6 mg/dL (range 1.6 to 3.9), including a mean serum creatinine level of 1.8 mg/dL (range 1.6 to 1.9) for nonrejected kidneys and a mean of 3.4 mg/dL (range 2.5 to 3.9) in those found to have concurrent rejection. Overall, five (63%) of eight procedures were successful in 5 (83%) of 6 patients. No intraoperative complications occurred and no blood transfusions were required. CONCLUSIONS: Balloon cautery endoureterotomy was successful in this select group of renal transplant patients with persistent ureteral strictures after initial balloon dilation and stenting failed. This modality proved durable to 27 months of follow-up without significant complications.

Laparoscopic nephrectomy and autotransplantation for severe iatrogenic ureteral injuries.

OBJECTIVES: To evaluate the efficacy of laparoscopic nephrectomy with autotransplantation in cases of severe proximal ureteral damage. Many patients with complex proximal ureteral injuries have good functional renal parenchyma and wish to salvage their kidney. Autotransplantation is a viable alternative to nephrectomy in these frustrating situations. METHODS: Two patients, aged 32 and 36 years, underwent laparoscopic nephrectomy and autotransplantation for treatment of severe proximal ureteral injuries. The injuries included a ureteropelvic junction avulsion and a proximal ureteral avulsion, respectively. Both patients had good functional renal parenchyma. A transperitoneal laparoscopic approach was used, and the kidney was removed by way of a Gibson incision. RESULTS: The procedures were successful, with immediate return of renal function in both patients. A pyeloureterostomy to the native distal ipsilateral ureter was required in one and a direct ureterovesical anastomosis was performed in the other. In the 2 patients, the warm ischemia time was 4.5 and 4 minutes, the transplant operative time 175 and 150 minutes, and the estimated blood loss 150 and 75 mL, respectively. No intraoperative complications occurred. At follow-up, the kidneys were functional, and the patients had returned to their normal activity. CONCLUSIONS: Laparoscopic nephrectomy with autotransplantation is an excellent alternative to nephrectomy or bowel interposition in patients with proximal ureteral loss, irrespective of the contralateral renal function. This procedure is associated with acceptable morbidity and preserves the renal function. This approach is desirable in those patients who have had complications from other surgical procedures and are otherwise facing the loss of a normally functioning kidney.

Transperitoneal preperitoneal laparoscopic lumbar incisional herniorrhaphy.

PURPOSE: Flank incisions may be associated with flank hernias, which may be complicated by incarceration and strangulation. Furthermore, they may be the cause of significant patient dissatisfaction with the surgical outcome. To avoid an open surgical procedure with its associated morbidity for hernia repair we describe a novel laparoscopic technique for repairing flank hernias with minimal morbidity and an excellent outcome. MATERIALS AND METHODS: Three cases of flank hernia were managed by the transperitoneal preperitoneal laparoscopic approach using polypropylene mesh to repair the fascial defect. An initial transperitoneal approach helps to identify the limits of the hernia. A 2 to 3 cm. margin of overlying peritoneum is incised around the hernia margin. It is important not to dissect overlying bowel. The mesh is placed behind the peritoneal envelope and secured with hernia staples. RESULTS: All cases were managed successfully via laparoscopy. There were no intraoperative or postoperative complications. At a mean followup of 12 months cosmesis has been excellent and there have been no recurrences. CONCLUSIONS: We describe a minimally invasive, versatile technique for laparoscopic repair of flank incisional hernias with excellent functional and cosmetic results. This approach avoids the significant morbidity associated with open repair of incisional flank hernias.

The laparoscopic cigarette sponge.

PURPOSE: Minor hemorrhage during laparoscopic procedures may obscure the operative field. We describe the use of an especially designed, 4 x 4 absorbent sponge for multiple laparoscopic applications. MATERIALS AND METHODS: The cigarette sponge, also known as the Kittner roll gauze, was routinely used for laparoscopic upper tract procedures. The sponge may be placed easily through ports 5 mm. or greater. RESULTS: The cigarette sponge was excellent for absorbing minor but bothersome bleeding, facilitating suction and blunt dissection, and assisting with retraction. CONCLUSIONS: This especially designed laparoscopic sponge dramatically eases laparoscopic procedures, especially for controlling bothersome hemorrhage and blunt dissection. It may decrease operative time and facilitate difficult laparoscopic procedures.

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.

Correlation of unilateral urolithiasis with sleep posture.

PURPOSE: Recurrent stone formers commonly present with calculi on the same side and the etiology of recurrent unilateral urolithiasis is unclear. Despite comprehensive metabolic evaluations, many patients will not be readily categorized into a treatable group. Data from the literature support that sleep posture may result in alterations of renal hemodynamics. We investigate the correlation of sleep posture with unilateral urinary stone formation. MATERIALS AND METHODS: A prospective study of 110 patients with recurrent unilateral nephrolithiasis was conducted. A questionnaire was used to evaluate patient sleep posture. Right or left side down and rotisserie-like sleep postures were defined. The side of stone formation was correlated with sleep posture using chi-square test. RESULTS: Of the patients 93 slept consistently with 1 side in a dependent position and the side of stone was identical to the dependent sleep side in 76% (p = 0.008). The positive predictive values of right and left side down sleep posture for formation of ipsilateral calculi were 82% and 70%, respectively. CONCLUSIONS: Although the exact pathophysiology of the association between sleep posture and recurrent unilateral stone disease remains to be elucidated, sleep posture may alter renal hemodynamics during sleep and promote stone formation. This observation needs further investigation and should be factored into the evaluation and prevention of unilateral urinary stone disease.

Laparoscopic live donor nephrectomy at the University of California San Francisco.

Laparoscopic donor nephrectomy is quickly becoming the preferred technique for kidney retrieval, since it removes many of the disincentives of kidney donation. Our experience at UCSF has confirmed that the procedure is safe, with excellent donor recovery. The transplanted kidney appears to function as well as any kidney retrieved using an open technique, at least in the short-term. Development of a successful laparoscopic donor program is best done initially with a team approach, utilizing the skills of an advanced laparoscopic surgeon, and with careful patient selection. With time, the technique can be done well by properly trained transplant surgeons with basic laparoscopic skills, with or without a hand-assist technique. As experience grows, this procedure can be applied to virtually every potential donor, and hopefully will improve live kidney donation rates.

Percutaneous management of caliceal diverticula.

The diagnosis of a caliceal diverticulum may be serendipitous or established owing to patient symptoms. Once the decision to treat a diverticulum has been made, a percutaneous approach should be considered. If stones are present, complete stone removal and obliteration of the diverticulum should be the goals of surgery. The authors prefer the direct puncture technique whenever possible to limit the risk for bleeding and to facilitate stone removal. Use of a percutaneous approach in properly selected patients affords high success rates and results in few complications.

Metabolic and urinary risk factors associated with Randall's papillary plaques.

BACKGROUND AND PURPOSE: Increasing evidence suggests that Randall's plaques contribute to the pathogenesis of urinary stone formation. The purpose of our study was to evaluate the urinary risk factors of stone patients who underwent endoscopic mapping of their calices for Randall's plaques. PATIENTS AND MATERIALS: Patients (N = 143) having endoscopic procedures to remove upper tract calculi or for other purposes underwent mapping of their calices for Randall's plaques. Plaque incidence and pattern were correlated with the stone composition and urinary risk factors found on subsequent metabolic evaluation. RESULTS: Papillary plaques were found more commonly in patients having calcium oxalate stones than in patients with other stone types and patients without a history of stones. Papillary plaque incidence and pattern did not correlate with any specific urinary risk factor; however, patients with plaques tended to exhibit a higher incidence of all risk factors. Plaque severity tended to be greater in patients exhibiting hypercalciuria. CONCLUSIONS: Randall's plaques are found most frequently in patients with calcium oxalate stones and are most important in the pathogenesis of calcium oxalate nephrolithiasis. Stone patients with papillary plaques are more likely to exhibit abnormalities in their urinary milieu than are patients without papillary plaques.

Endourologic management of urinary fistulae.

PURPOSE: Historically, aggressive surgical exploration of renal fistulae has been associated with a 20% nephrectomy rate. We evaluated the role of minimally invasive techniques in the management of urinary fistulae. MATERIALS AND METHODS: A retrospective review identified 10 renal fistulae in nine patients. Six renal-cutaneous, two renal-colonic, and two renal-pleural fistulae were referred for evaluation and treatment. RESULTS: Five men and four women (mean age 54 years, range 32-76) were referred to the University of California, San Francisco Urinary Stone Center from 1988 to 1996. Of the six renal-cutaneous fistulae, four were spontaneous and two were iatrogenic. The iatrogenic fistulae occurred after an open pyelolithotomy (1) and a renal exploration performed after extracorporeal shock wave lithotripsy (1). The spontaneous fistulae resulted from obstructing calyceal calculi (2), infundibular stenosis (1), and obstructed nephrostomy tube (1). The two renal-colonic fistulae resulted from percutaneous nephrolithotomies, and the two renal-pleural fistulae developed after renal surgery. Eight of 10 fistulae resolved with minimally invasive endoscopic techniques and relief of urinary obstruction. One nephrectomy was performed for a small nonfunctioning kidney after failed open pyelolithotomy. One patient refused all treatment and the fistula resolved spontaneously. CONCLUSIONS: Conservative management of both spontaneous and iatrogenic renal fistulae is possible by relieving urinary obstruction and using minimally invasive endoscopic techniques. Low nephrectomy rates can be expected using these methods.

Impact of body weight on urinary electrolytes in urinary stone formers.

OBJECTIVES: Obesity increases the risk of developing chronic medical conditions such as diabetes mellitus, hypertension, and coronary artery disease. We performed a retrospective review of a large data base on urinary stones to determine if differences are found in urine and serum chemistries among obese and nonobese stone-forming patients. The effect of body weight on stone recurrence among urinary stone formers was also determined. METHODS: A national data base containing serum biochemical profiles, 24-hour urine specimens, and standardized questionnaires was retrospectively evaluated from 5942 consecutive patients with urinary stone disease. Stone-forming patients were classified by body weight: nonobese men, less than 100 kg and nonobese women, less than 85 kg; intermediate men, 100 to 120 kg and intermediate women, 85 to 100 kg; and obese men, more than 120 kg and obese women, more than 100 kg. RESULTS: Obese stone formers comprised 6.8% (n = 404) of the patient population. The mean weight in the nonobese and obese groups was 81 kg versus 134 kg, respectively, for men and 64 kg versus 112 kg, respectively, for women. Obese patients represented 3.8% of the male and 12.6% of the female population. Obese patients had increased urinary excretion of sodium, calcium, magnesium, citrate, sulfate, phosphate, oxalate, uric acid, and cystine; obesity was associated with increased urinary volumes and urine osmolality compared with the nonobese patients. Obese men had increased concentration of urinary sodium, oxalate, uric acid, sulfate, and phosphate when corrected for urinary volume. Obese women had increased concentrations of sodium, uric acid, sulfate, phosphate, and cystine. The mean number of stone episodes in nonobese versus obese men was similar (3.55 and 3.56), whereas mean stone episodes were 2.93 and 3.38 (P = 0.045) for nonobese versus obese women. CONCLUSIONS: Among known stone formers, obesity is associated with unique changes in both serum and urinary chemistries. These changes are associated with an increased incidence of urinary stone episodes in obese women but not in obese men.

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.

An in vitro assessment of the flow characteristics of spiral-ridged and smooth-walled JJ ureteric stents.

OBJECTIVE: To assess drainage through spiral-ridged and smooth-walled JJ ureteric stents (designed to ensure upper tract drainage) and thus determine whether drainage preferentially occurs around rather than through the spiral-ridged stent, promoting renal flow and potentially facilitating the passage of urinary stone fragments. Materials and methods A mechanical ureteric model was constructed to mimic the funnel characteristics of the renal pelvis. A motor pump was used to help simulate respiratory and skeletal movement, resulting in differential motion between the intraluminal stent and the surrounding ureteric wall. Tubes of varying internal diameters were used to simulate different sizes of ureter. Flow rates of standard 7 F smooth-walled stents were compared with 7 F spiral-ridged stents with and without occluded lumens, and with and without standardized excursions. RESULTS: Extraluminal flow (mean rates) with and without movements simulating respiratory excursions were significantly higher with the spiral stent for all stent diameters evaluated. All flow rates increased as the ureteric diameter increased. Total flow past the spiral stent was significantly greater than flow with the smooth-walled stent under all conditions tested. Flows measured around the spiral stent under conditions of excursion were the highest of all categories, 20-fold higher than in smooth-walled, closed, stationary stents. CONCLUSION: Spiral-ridged JJ stents provided substantially greater flow in this in vitro model. Extraluminal flow was markedly increased with the spiral-ridged configuration. The difference in flow rates was more pronounced at the smaller pseudo-ureteric tube diameters, simulating dimensions found in clinical practice. The flow rate also was increased when the central lumen remained open, and was greater still when there was dynamic excursion with respiratory movements.

Gahat: a Napalese cure for urolithiasis?

OBJECTIVES: Gahat (Vigna unguiculata) is a legume used for centuries in Nepal and Pakistan to treat the symptoms associated with urinary calculi. We prospectively evaluated the effect of Gahat consumption on 24-hour urine parameters in an attempt to assess its in vivo effect in normal volunteers. METHODS: Eight non-stone-forming volunteers collected 24-hour urine specimens while on their routine diets for baseline data. Urine was analyzed for pH, volume, calcium, citrate, phosphate, sodium, magnesium, uric acid, and oxalate. The Gahat was prepared according to local custom. No additives were used to enhance flavor. The pureed mixture (8 ounces) was ingested three times daily for 2 days. Subjects were instructed to maintain their normal diet, including fluid intake and activity during the study period. Twenty-four hours after the start of Gahat intake, a second 24-hour urine collection was initiated while volunteers continued the Gahat. Results of the urine samples before and after Gahat intake were analyzed, using the paired Student t test. RESULTS: There were no significant differences in urinary electrolytes between the urine samples before and after Gahat intake. Magnesium, urine volume, and uric acid differences approached clinical significance. CONCLUSIONS: Gahat increased urinary magnesium through an unknown mechanism and had no effect on other routine 24-hour urine electrolytes. The increase in urinary volume is attributed to the increase in fluid consumption by the subjects. If this legume is effective in preventing or dissolving urinary calculi, it may act through mechanisms not identified in 24-hour urine electrolytes.