Eliminating the Residual Negative Pressure in the Endoscopic Ultrasound Aspirating Needle Enhances Cytology Yield of Pancreas Masses

Abstract

BACKGROUND Prior to withdrawing the EUS-FNA needle from the lesion, the stopcock of the suction-syringe is closed to reduce contamination. Residual negative pressure (RNP) may persist in the needle despite closing the stopcock. AIMS To determine if neutralizing RNP before withdrawing the needle will improve the cytology yield. METHODS Bench-top testing was done to confirm the presence of RNP followed by a prospective, randomized, cross-over study on patients with pancreas mass. Ten-mL suction was applied to the FNA needle. Before withdrawing the needle from the lesion, the stopcock was closed. Based on randomization, the first pass was done with the stopcock either attached to the needle (S+) or disconnected (S−) to allow air to enter and neutralize RNP and accordingly the second pass was crossed over to S+ or S−. On-site cytopahtologist was blinded to S+/S−. RESULTS Bench tests confirmed the presence of RNP which was successfully neutralized by disconnecting the syringe (S−) from the needle. Sixty patients were enrolled, 120 samples analyzed. S+ samples showed significantly greater GI-tract contamination compared to S− samples (16.7% vs. 6.7%, p=0.03). Of the 53 patients confirmed to have pancreas adenocarcinoma, FNA using S− approach was positive in 49 (93%) compared to 40 using the S+ approach (76%, p=0.02). CONCLUSIONS Despite closing the stopcock of the suction-syringe, RNP is present in the FNA needle. Neutralizing RNP prior to withdrawing the needle from the target lesion significantly decreased GI-tract contamination of the sample thereby improving the FNA cytology yield.

Diagnostic accuracies of endoscopic ultrasound-guided fine-needle aspiration with distinct negative pressure suction techniques in solid lesions: A retrospective study

“…All procedures were performed with a standard technique, which utilized a linear array echoendoscope (Olympus GF-UCT 240; Olympus Corporation, Tokyo, Japan) and an Alpha 5 Aloka processor (Hitachi-Aloka Medical, Ltd., Tokyo, Japan). During the individual EUS-FNA passes, the stylet was reproducibly removed with a slow-pull technique, and a 10 ml syringe with 5 or 10 ml suction technique (25)(26)(27) was attached to the proximal end of the needle. The needle was then moved back and forth 12-16 times while applying suction.…”

Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Gastrointestinal and Pancreatic Tumors: Is Negative Pressure Helpful or Does It Suck?

“…In summary, Aadam et al [4] report that despite closing the stopcock of the suction syringe, negative pressure persists in the FNA needle, not just proximal to the aspirated material but also up to the tip. Residual negative pressure contaminates the sample with unaffected GI tract tissue, which may lead to the misinterpretation of cytology specimens and thus affect cytologic yield.…”

“…If the obtained specimen is minimal, such as in cases of chronic pancreatitis, negative pressure can be used to enable the acquisition of a larger specimen [1]. Nonetheless, while most reports focus on cytology, histological tissue quality has rarely been investigated.In this issue of Digestive Diseases and Sciences, Aadam et al [4] hypothesized that negative pressure still persists in the aspirating needle despite closing the suction-syringe stopcock. They first examined the effect of stopcock closure and the removal of the syringe itself using an in vitro model system that confirmed the presence of residual negative pressure inside and up to the tip of the needle after closing the stopcock that was successfully neutralized by removing the syringe.…”

“…In this issue of Digestive Diseases and Sciences, Aadam et al [4] hypothesized that negative pressure still persists in the aspirating needle despite closing the suction-syringe stopcock. They first examined the effect of stopcock closure and the removal of the syringe itself using an in vitro model system that confirmed the presence of residual negative pressure inside and up to the tip of the needle after closing the stopcock that was successfully neutralized by removing the syringe.…”

“…Cytological and histological analyses of the obtained samples should also be evaluated by adequacy scoring systems in future prospective RCTs. Aadam et al [4] suggested that residual negative pressure may increase contamination from the GI tract, which reduces cytological diagnostic yields, especially on the first slide. Yet, the influence of GI tract contamination on histological evaluation has not been fully established.…”