Surgical Factors Influencing Local Relapse and Outcome in the Treatment of Unilateral Nephroblastoma.

OBJECTIVE: This study aims to identify factors associated with the occurrence of local relapse (LR) after treatment for unilateral nephroblastoma. BACKGROUND: Despite the fact that LR is rare (~5%) its adverse impact on the need for relapse treatment and outcome (40%-80% overall survival) cannot be neglected. Identifying the causative factors may improve initial treatment to achieve better local control. METHODS: Altogether 2386 patients with unilateral nephroblastoma prospectively enrolled over a period of 32 years (1989-2020) by the German Society for Pediatric Oncology and Hematology (SIOP-9/GPOH, SIOP-93-01/GPOH and SIOP-2001/GPOH) were retrospectively analyzed. Hazard ratios (HR) of LR were calculated for sex, age, size, local staging, histology, type of removal, rupture, lymph node (LN) removal using univariate and multivariate Cox models. RESULTS: Age >48 months, tumor volume >500 mL, histology and LN extent of removal were identified as significant risk factors for LR [HR: 1.68, P =0.018, confidence interval (CI): 1.09-2.58; HR: 1.84, P =0.015, CI: 1.13-3.00; HR: 3.19, P <0.001, CI: 2.03-5.00; HR: 2.26, P =0.002, CI: 1.36-3.576]. LR occur significantly more often in Stage I and II, even if no LN are removed. The risk of metastases is significantly increased after local recurrence (HR: 11.5, P <0.001, CI: 7.11-18.60). LR is associated with a subsequent 18.79-fold increased risk of death (HR: 18.79, P <0.001, CI: 2.07-5.28). CONCLUSIONS: Several factors are responsible for the occurrence of LR. Surgical ones, like LN sampling allow further reduction of LR and consequently a better outcome of patients with unilateral nephroblastoma.

A novel adaptation of laparoscopic Tenckhoff catheter insertion technique to enhance catheter stability and function in automated peritoneal dialysis.

INTRODUCTION: Automated peritoneal dialysis (APD) normally takes place overnight. Maintaining a stable PD catheter position, independent of body position, omental wrapping or catheter displacement secondary to bowel movements is essential in maintaining effective catheter function. METHODS: We developed a new procedure of catheter placement through combining and adapting several previously described operative techniques including laparoscopic placement of a curled double cuff Tenckhoff catheter with subcutaneous tunneling superior to the rectus sheet, an oblique course through the abdominal wall, deep entry into the pelvic peritoneum and directed placement of the curled tip within the pouch of Douglas. Retrospective analysis of catheter function was conducted, evaluating catheter position, function, complication rate and catheter survival against findings for current insertion techniques described within literature. RESULTS: Between March 2009 and November 2011, 54 patients underwent PD catheter insertion. The observation period was an average of 343 ± 273 days. All patients received abdominal plain film showing optimal catheter position in 89 %. Reported catheter function was very good in 85.2 %, with no or few alarms per week during APD, moderate in 9.3 % with occasional minor dysfunctions (≤ 2 alarms per night), and poor in 5.6 %, with regular alarm disturbance. In one case, primary dysfunction led to catheter replacement. At completion, stable catheter function with occasional minor dysfunction was achieved in 52 of 54 cases. Catheter-related complications (leakage, hydrocele formation, infection and need for replacement) were observed in 14.8 %. At the end of the observation period, 55.6 % of catheters remained in use. Patient dropout occurred through death (18.5 %), renal transplantation (7.4 %), renal recovery (1.9 %), removal secondary to infection or dysfunction (9.3 %) and conversion to HD due to poor dialysis quality (7.4 %). CONCLUSION: The above technique combines and optimises previously described laparoscopic catheter implantation techniques, allowing increased catheter stability resulting in an undisturbed catheter function suitable for APD.

A material stress test study on occurrence of leakage and material failure of peritoneal dialysis (PD) catheters.

Peritonitis is a common complication of peritoneal dialysis (PD). Our root cause analysis allowed to attribute some cases to leakage of the PD catheter. Accordingly, a clinically based stress test study on potential material damage issues of PD catheters was performed, focusing on material damage caused by cleaning, de- and attachment procedures during dialysate changes and on the individual storage methods of PD catheters between dialysate changes. PD catheters were exposed to both chemical stress by repeating dialysate-flow and physical stress simulating de- and connecting, fixation, pressure, flexing, folding etc.-simulating standard clinical daily routine of 8-10 years PD catheter usage. Potentially by normal usage caused damages should be then detected by intraluminal pressure, light- and electron microscopy. The multi-step visual control showed no obvious damages on PD catheters nor any leakage or barrier indulgence. Our tests simulating daily routine usage of PD catheters for several years could not detect any material defects under chemical or physical stress. Hence, we presume that most PD catheter damages, as identified cause for peritonitis in some of our patients, may be due to accidental, unnoticed external damage (e.g. through scissors, while changing dressings) or neglecting PD catheter handling specifications.