Aetiology of non-diagnostic renal fine-needle aspiration cytologies in a contemporary series.

OBJECTIVES: To determine the aetiology of non-diagnostic renal fine-needle aspiration cytologies (FNACs) in a contemporary series. PATIENTS AND METHODS: We retrospectively reviewed our institutional database of renal FNACs performed between 1995 and 2005. There were 118 patients with renal lesions that underwent FNAC. Indications for FNAC were indeterminate complex renal cysts, significant medical comorbidities, previous history of malignancy, multiple bilateral renal lesions, and suspected metastatic disease. A cytotechnologist was present during the FNA procedure to perform Diff-Quik staining and ensure an adequate sample of cells were obtained. Except for seven (six open, one ultrasound-guided), all of the FNACs were performed with CT guidance. RESULTS: The median (range) number of passes for each FNAC session was 2.7 (1-6). Of the 16 FNACs performed for indeterminate complex renal cysts, nine (56%) were adequate with the cytodiagnosis of benign cysts. Of the seven inadequate specimens, three had benign cysts and another three were non-diagnostic due to acellularity. Therefore, the technical failure rate was 19% (3/16) for indeterminate complex renal cysts. The last patient had a cytodiagnosis of benign cyst and the final histological diagnosis of renal cell carcinoma (RCC; papilllary, grade III). Therefore, this represents a sampling error (false negative rate) of 0.8% (1/118). For the 102 solid renal masses, 22 (22%) had inadequate specimen by Diff-Quik staining. The technical failure rate (inability to obtain sufficient epithelial cells) was 16% (16). In 18 patients, immunocytochemistry (ICC) was used to differentiate primary renal parenchymal tumours from others such as transitional cell carcinoma (TCC), lymphoproliferative, colon, and lung. There were two FNACs with misdiagnosis (2%), where ICC was not used. In both, the cytodiagnosis was TCC and the final histological diagnosis was RCC in one and atypical urothelium in another. CONCLUSIONS: Non-diagnostic renal FNACs can be attributed to misdiagnosis (2%), sampling error (0.8%) and technical failure (16%).

Number of needle passes does not correlate with the diagnostic yield of renal fine needle aspiration cytology.

BACKGROUND AND PURPOSE: Renal Fine Needle Aspiration Cytology (FNAC) has gained popularity due to increasing options in management of renal lesions such as energy ablation and active surveillance. The diagnostic yield of renal FNAC varies between 40-90%. We hypothesized that adequate and diagnostic FNA samples would be associated with higher number of needle passes and higher number of slides examined. PATIENTS AND METHODS: The pathology database at our institution was retrospectively searched for renal FNACs performed between 1995 and 2005. Patient gender, side, indication, cytological diagnosis, final histological diagnosis when available, number of needle passes performed, number of slides examined, and adequacy of the FNAC sample as determined by Diff Quik staining by the cytotechnologist (CS) were recorded. Chi square test was performed for statistical analysis. RESULTS: Out of 377 renal biopsies performed, 259 were core biopsies for medical renal disease, and 118 were FNACs for renal lesions, including 16 for indeterminate complex renal cysts and 102 for solid renal masses. Indeterminate renal cysts were excluded from the study. Out of 102 FNACs for solid renal masses, 22 were inadequate with 13 (59%) being non-diagnostic; and 80 FNACs were adequate with 3 (4%) being non-diagnostic. The number of needle passes was not significantly different between non-diagnostic and diagnostic samples (2.5 vs 3.2); and between inadequate and adequate samples (3.4 vs 3.0). Similarly, the number of slides examined was not significantly different between non-diagnostic and diagnostic samples (9.5 vs 10.9); and between inadequate and adequate samples (11.3 vs 10.6). Diff Quik adequate samples had significantly higher diagnostic yields when compared to Diff Quik inadequate samples (965 vs 41%; p<0.01). CONCLUSIONS: The number of needle passes and microscopic slides examined did not correlate with sample adequacy or diagnostic yield of renal FNAC. Sample adequacy as determined by Diff Quik staining correlated with diagnostic FNAC. Despite the retrospective nature of this study, a cytotechnologist should be present during the FNA procedure to ensure adequate samples have been obtained to increase the diagnostic yield of renal FNAC.

Device failures associated with patient injuries during robot-assisted laparoscopic surgeries: a comprehensive review of FDA MAUDE database.

INTRODUCTION: Robot-assisted laparoscopic surgery has increased in the areas of cardiac and urologic surgery. We sought to determine the number of reported device malfunctions leading to patient injuries. METHODS: We performed a review of the MAUDE database of the FDA. Adverse events (AE) were defined as potential and actual product use errors and product quality problems. All incidents involving the ZEUS and da Vinci surgical robots were analyzed. RESULTS: The MAUDE database was last accessed on August 27, 2007. A total of 189 AEs were reported from 2000 to August 27, 2007. Assuming that 50,000 robotic-assisted laparoscopic cases have been performed, this represents 0.38% overall estimated failure rate. Twenty-one malfunctions were reported for the ZEUS robotic system between 2001 and 2003, while 168 malfunctions were reported for the da Vinci robotic system between 2000 and 2007. The rate of open conversions due to device malfunction decreased from 94% in 2003 to 16% in 2007. Of the 189 reported device malfunctions, only 9 (4.8%) were associated with patient injury. CONCLUSIONS: The increasing use of robotic-assisted surgery has led to an increase in the number of reported device malfunctions, albeit at a very small estimated rate of 0.38%. With experience, the rate of open conversions due to device malfunction decreased. Only a small percentage of these adverse occurrences were associated with patient injury.