How to get a high quality specimen from your EOS guided liver biopsy with one pass every time. Endoscopic ultrasound guided liver biopsy is a promising alternative to existing percutaneous and transjugular liver biopsy approaches. Concerns regarding specimen adequacy as well as a lack of procedural standardization have limited the widespread adoption of EOS guided liver biopsy. There is a need for the identification of a safe and reproducible sampling technique capable of maximizing specimen adequacy while minimizing fragmentation, blood contamination, and the number of needle passes through the liver capsule. In this video, we aim to show you how to guarantee a high quality specimen from your EOS liver biopsy the first time and every time. We will provide a clear step-by-step demonstration of a novel protocol for EOS liver biopsy termed the hydrostatic stylet technique which was developed to optimize specimen quality. Finally, we will share data on efficacy and safety showing that excellent specimens can be reliably acquired using this novel hydrostatic stylet technique with a single pass. First, the stylet is removed from the 19-gauge franzine tip FNB needle. The needle channel is then flushed with sterile water to purge air. The stylet is then partially reinserted up to 30 centimeters. This is to reduce friction between the stylet and the needle within the articulating portion of the endoscope and to preserve a hydrostatic column of fluid between the stylet and needle tip. The targeted liver is visualized endosonographically. Color doppler imaging is also used to confirm the absence of blood vessels within the needle path. The echoendoscope is advanced to the gastric body for biopsy of the left liver lobe and to the duodenal bulb for biopsy of the right liver lobe. The technique remains the same for both. After estimating and confirming the projected needle path, the needle is advanced with a single sharp thrust through the liver capsule and into the liver parenchyma. An external view of the technique is shown here. Prior to puncture, the assistant must brace their arm against a fixed object and hold the stylet motionless relative to the patient while the needle is advanced through the target tissue. The assistant then releases the stylet and the endoscopist carefully withdraws the needle until it is close to the liver capsule edge. A second actuation is typically performed with a slightly different trajectory. Note that the needle traverses the capsule and the gastric wall only once to minimize the risk of bleeding. The assistant then releases the stylet and the endoscopist withdraws the needle and the puncture site is visualized with color doppler to detect any local bleeding. The sample is then expressed directly into a formalin jar by reinserting the stylet until the column of residual water above the specimen is ejected. Representative histological slides are shown here. A low power microscopic view on the left showing a long non-fragmented liver core and a high power microscopic view on the right showing multiple portal tracks in one microscopic field. Key tips to guarantee a great specimen with one pass every time. Number one, flush the needle with water prior to reinserting the stylet. This is to provide lubrication and a hydrostatic column of fluid to transmit negative pressure to the needle tip. Number two, leave 30 centimeters of stylet outside the needle when preparing for the procedure. This is to minimize friction within the articulating portion of the endoscope and to allow the assistant to perform the next step well. Number three, ensure the assistant holds the stylet perfectly motionless relative to the patient while you advance the needle. Number four, advance the needle with a sharp thrust to near but not through the contralateral edge of the liver. And lastly, number five, avoid passage through the viscous wall and liver capsule more than once even if multiple actuations are performed as this step is the highest risk for bleeding and pain. The hydrostatic stylet technique overcomes several limitations associated with previously described EUS liver biopsy techniques. Compared to a previously described wet heparin suction technique, the hydrostatic stylet technique obviates the need to strain the liver core from surrounding blood and blood clots prior to fixation and formalin. Our local institutional experience also confirms that the hydrostatic stylet technique offers improved histological adequacy. We conducted a retrospective analysis of all patients undergoing EUSLB via the hydrostatic stylet or wet heparin suction techniques from 2020 to 2022. In the 48 patient cohort with 21 in the hydrostatic stylet group and 27 in the heparin suction group, compared to the wet heparin suction approach, the hydrostatic stylet technique required a significantly lower mean number of needle passes to obtain a 100% diagnostic adequacy rate. The HS technique generated samples with a greater mean number of complete portal triads. The HS technique demonstrated lower specimen fragmentation scores. The HS technique maintained low blood contamination scores despite, as previously stated, eliminating the need to separate the core from blood prior to formalin fixation and finally was shown to be safe with one patient with abdominal pain in each group both resolved with observation. 100% of the samples obtained via the hydrostatic stylet technique met the minimum threshold of complete portal triads greater than or equal to 11 for the procurement of a high quality liver biopsy sample as determined by numerous liver society guidelines. The use of this novel hydrostatic stylet technique in EOS guided liver biopsy is capable of routinely and safely obtaining high quality liver biopsy specimens. The hydrostatic stylet technique overcomes several limitations of previously reported techniques and notably minimizes the risk of multiple needle passes through the liver capsule. Finally, improving technical standardization of EOS-LB will increase the widespread adoption of the procedure.

endoscopic ultrasound-guided liver biopsy

EOS-LB

hydrostatic stylet technique

specimen adequacy

needle passes