Mixed stones: urinary stone composition, frequency and distribution by gender and age

Proper analysis of urinary stone composition is a cornerstone for diagnosis, targeted treatment and recurrence prevention of urolithiasis. The aim of this study was to determine the composition, frequency and distribution of mixed stones according to gender and age of patients. A total of 42,519 urinary stones from 30,311 men and 12,208 women submitted between January 2007 and December 2020 were studied. Most urinary calculi consisted of two components (50.9%), followed by stones of a single constituent (27.1%) and three-component stones (21.9%), while four-component stones were only rarely identified (0.1%). Among all stones, 49.8% consisted of whewellite (COM), weddellite (COD), and mixtures of COM and COD, 33.8% were pure carbonate apatite (CA) and mixtures of CA with COM and/or COD, while 7.6% were composed of uric acid anhydrous (UAA), uric acid dihydrate (UAD), and mixed UAA and UAD. The remaining 8.8% of calculi were rare single-component stones and rare mixtures of various constituents. The number of stone components was inversely associated with age (p < 0.001). The proportion of men decreased significantly with the number of stone constituents, from 3.01:1 for single-component stones to 1.0:1 for four-component urinary calculi (p < 0.001). The vast majority of urinary calculi consisted of two or more components in varying proportions. While age was inversely associated with the number of stone constituents, the proportion of women increased significantly from single-component to four-component urinary calculi. A significant proportion of mixed stones could present a challenge for diagnosis and targeted recurrence prevention.

Urinary stone composition in Germany: results from 45,783 stone analyses

Purpose

Stone composition can provide valuable information for the diagnosis, treatment and recurrence prevention of urolithiasis. The aim of this study was to evaluate the distribution of urinary stone components and the impact of different crystal forms according to gender and age of patients in Germany.

Methods

A total of 45,783 urinary stones submitted from 32,512 men and 13,271 women between January 2007 and December 2020 were analyzed by infrared spectroscopy. Only the first calculus obtained per patient was included in the analysis.

Results

The most common main stone component was calcium oxalate (CaOx) (71.4%), followed by carbonate apatite (CA) (10.2%) and uric acid (UA) (8.3%). Struvite (2.1%), brushite (1.3%), protein (0.5%) and cystine (0.4%) stones were only rarely diagnosed. CaOx (75%) and UA stones (81%) were more frequently obtained from men than women (p < 0.001). Weddellite (COD) and uric acid dihydrate (UAD) were more common in younger ages than whewellite (COM) and anhydrous uric acid (UAA), respectively, in both men and women. The ratios of COM-to-COD and UAA-to-UAD calculi were approximately 4:1 and 8:1, respectively. The peak of stone occurrence was between the ages of 40 and 59 years.

Conclusion

Stone composition is strongly associated with gender and age. The peak incidence of calculi in both women and men was in the most active phase of their working life. The distinction between different crystal forms could provide clues to the activity and mechanisms of lithogenesis. Further research is needed in understanding the causative factors and the process of stone formation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-022-04060-w.

Complications of primary nerve sparing retroperitoneal lymph node dissection for clinical stage I nonseminomatous germ cell tumors of the testis: experience of the German Testicular Cancer Study Group

PURPOSE

Nerve sparing retroperitoneal lymph node dissection has been the standard diagnostic and therapeutic approach to clinical stage I nonseminoma. However, the application of prognostic risk factors and introduction of laparoscopy have recently called into question the clinical usefulness of nerve sparing retroperitoneal lymph node dissection. We assessed the therapeutic efficacy and associated complications of this procedure in patients with clinical stage I nonseminomatous germ cell tumor treated at 7 tertiary referral centers to evaluate its role in the modern management of low stage testis cancer.

MATERIALS AND METHODS

Between January 1995 and September 2000, 239 patients with clinical stage I nonseminomatous germ cell tumor underwent nerve sparing retroperitoneal lymph node dissection in standardized fields of dissection. For retrospective analysis patient charts were reviewed. A minor complication did not prolong hospital stay and a major complication prolonged hospitalization for at least 2 days. Early complications developed within the first 30 days after retroperitoneal lymph node dissection and late complications occurred from postoperative day 31 and thereafter.

RESULTS

Nerve sparing retroperitoneal lymph node dissection was performed unilaterally in 209 patients (88.2%) and bilaterally in 30 (11.8%). Median operative time was 214 minutes (range 90 to 395), mean hospital stay was 8 days (range 4 to 39) and mean blood loss was less than 150 ml. A mean of 18.5 lymph nodes (range 9 to 57) were dissected with metastases detected in 67 patients (28%). An average of 2.9 lymph nodes (range 1 to 14) with a mean diameter of 2.6 cm. (range 0.3 to 6.0) showed metastasis. Disease was pathological stage I in 172 patients (71.7%), 52 (17.6%) had 3 or fewer metastatic lymph nodes, and 15 (6.3%) had 4 to 5 and 10 (4.2%) had greater than 5 positive lymph nodes. Minor complications occurred in 14.2% of the cases and major complications were observed in 5.4%. Antegrade ejaculation was preserved in 93.3% of the patients, recurrence developed in 14 (5.8%) and retroperitoneal recurrence was observed in 3 (1.2%), including 1 in field and 2 out field.

CONCLUSIONS

Primary diagnostic and therapeutic nerve sparing retroperitoneal lymph node dissection still has a role in the primary management of clinical stage I nonseminomatous germ cell tumor. Surgery is associated with low morbidity and patient followup is easy and cost-effective due to the concentration on extraretroperitoneal locations. Primary nerve sparing retroperitoneal lymph node dissection is curative in about 70% of clinical stage I nonseminoma cases with a maximum of 3 positive lymph nodes.

Vascular injuries within the hepatoduodenal ligament: recognition by laparoscopic color Doppler ultrasound

BACKGROUND

Lesions of vascular structures are rare but serious complications of laparoscopic cholecystectomy. The purpose of this blind randomized animal study was to investigate the possibility of detecting different vascular lesions within the hepatoduodenal ligament using laparoscopic color Doppler ultrasound (LCDU).

METHODS

Twenty-four lesions of the hepatic artery and portal vein were created laparoscopically in six farmer pigs using titanium clips. The following injuries were studied: (a) partial occlusion of the hepatic artery (eight cases), (b) complete occlusion of the hepatic artery (eight cases), (c) partial occlusion of the portal vein (eight cases). There were also eight cases without lesions of the vascular vessels. The order in which the injuries were created was randomly assigned. The study was performed in a blind fashion. Recognition of the injuries was attempted with LCDU.

RESULTS

All injuries were recognized correctly by LCDU. There were no false positive results. The clips were reliably located. Using color Doppler imaging, partial occlusions of the hepatic artery and portal vein were visualized by changes of the blood flow from laminar to turbulent behind the clip. Complete occlusion of the hepatic artery was recognized as a complete cessation of the colored blood flow.

CONCLUSION

LCDU is a very efficient tool for visualizing vascular structures and evaluating the bloodstream. Partial or complete vascular occlusion by clips that may occur as a result of difficult dissection during laparoscopic cholecystectomy can be visualized reliably using this technique.