Abdominal and pelvic needle aspiration biopsies: can we perform them well when using small needles?

Background: The aim of this study was to compare abdominal fine-needle aspi rations (FNAs) performed with large (greater than or equal to 20-gauge) or small (less than or equal to 21-gauge) needles for diagnostic rate, number of samples required for diagnosis, diagnostic accuracy, and complication ra tes. Methods: Abdominal and pelvic FNA procedures were retrospectively reviewed. Needle size, imaging guidance used, number of pathology slides created, co mplications, and cytologic and final diagnoses were obtained by reviewing r adiologic, medical, and cytology records. Results: Two hundred ninety procedures were included in the study. Two hund red fifty-seven were performed in patients having only one biopsy during th e study interval. Of these, 159 had biopsies using small needles and 98 usi ng large needles. Small needle biopsies had as high a diagnostic rate as di d large needle biopsies (97.5% vs. 92.9%, p = 0.11). Small and large needle biopsies showed high diagnostic accuracy (96.1 and 98.9%, respectively; p = 0.27). Incorrect cytologic diagnoses plus nondiagnostic examinations comp osed 6.3% of biopsies using small needles and 8.2% of biopsies using larger needles (p = 0.62). Complication rates were low. Aver age number of needle passes tended to be lower when small needles were used. Conclusion: Small needles can be successfully used for abdominal and pelvic FNAs. Small needles require the same or fewer needle passes, have low risk , have the same or improved ability to obtain diagnostic material, and achi eve correct diagnoses compared with larger needles.