The place of retroperitoneoscopic hemi-nephroureterectomy for duplex kidney in children; risk of damage to the remnant moiety and strategies to reduce the risk.

OBJECTIVE: To analyse the outcomes of retroperitoneoscopic upper and lower moiety hemi-nephroureterectomy (HNU) and to assess the different variables that may have an impact on outcome; remnant moiety damage, morbidity and the need for secondary surgery. METHODS: Prospectively recorded data of retroperitoneoscopic HNU's performed by a single surgeon from 2005 to 2018 were analysed. Patients were split into 2 groups according to moiety affected (UMHNU and LMHNU). Clinical presentation, underlying pathology, remnant moiety DRF on renal scintigraphy, and need for further surgery were recorded. Detailed operation notes were studied regards to renal vasculature, degree of dilatation, inflammatory changes and operative difficulties encountered. Renal loss was defined as remnant moiety DRF <10% post-operatively. Change in DRF was assessed regards to the moiety, pathology and age at surgery (<1 year, 1-2 years and ≥2 years). UMHNU group was further sub-divided into 3 subgroups: ureteroceles, ectopic ureters and 'other' pathology. Statistical analysis was performed using Fishers Exact test; findings were considered statistically significant at p < 0.05. RESULTS: 78 operations met the inclusion criteria on 75 patients (3 bilateral). There were no conversions to open, and 67% were performed as day-case procedures (53/78 patients). In 91.2% (71/78) patients the procedure was definitive in resolving pathology and symptoms. 7 patients needed further procedures after HNU, 5 for ureterocele/ureteric stump. Overall, there was remnant moiety renal loss in 5.1% (4/78) patients, all with UM surgery (3 ectopic ureters and 1 ureterocele). All 4 operations were recorded prospectively as 'difficult operations' due to grossly dilated UM ureter/pelvis measuring >2 cm in diameter. 2 patients had a thinned out lower moiety (LM) sitting on top of the UM renal pelvis like a pancake with all vessels stretched over this dilated pelvis/ureter causing difficulty in accurate identification. There was intra-operative concern about some damage to LM vessels in 3 patients. Age <1year was also related to increased renal loss (2/8 patients <1 year, 1/25 patients 1-2 years, 1/45 patients ≥2 years of age P = 0.005). CONCLUSION: Retroperitoneoscopic LMHNU is a safe and definitive procedure with rapid recovery and minimal scarring. UMHNU has higher rates of remnant moiety loss due to more complex renal pathology, but remains a safe, successful operation on the majority of patients. Renal damage was also related to age <1year (p = 0.005) and re-operation risk after UMHNU correlated to the presence of ureterocele (p = 0.003).

Advances in Distinguishing Groundwater Influenced by Oil Sands Process-Affected Water (OSPW) from Natural Bitumen-Influenced Groundwaters.

The objective of this study was to advance analytical methods for detecting oil sands process-affected water (OSPW) seepage from mining containments and discriminating any such seepage from the natural bitumen background in groundwaters influenced by the Alberta McMurray formation. Improved sampling methods and quantitative analyses of two groups of monoaromatic acids were employed to analyze OSPW and bitumen-affected natural background groundwaters for source discrimination. Both groups of monoaromatic acids showed significant enrichment in OSPW, while ratios of O2/O4 containing heteroatomic ion classes of acid extractable organics (AEOs) did not exhibit diagnostic differences. Evaluating the monoaromatic acids to track a known plume of OSPW-affected groundwater confirmed their diagnostic abilities. A secondary objective was to assess anthropogenically derived artificial sweeteners and per- and polyfluoroalkyl substances (PFAS) as potential tracers for OSPW. Despite the discovery of acesulfame and PFAS in most OSPW samples, trace levels in groundwaters influenced by general anthropogenic activities preclude them as individual robust tracers. However, their inclusion with the other metrics employed in this study served to augment the tiered, weight of evidence methodology developed. This methodology was then used to confirm earlier findings of OSPW migrations into groundwater reaching the Athabasca River system adjacent to the reclaimed pond at Tar Island Dyke.