In several countries fine needle aspiration (FNA) biopsy of soft tissue tumours is regarded as a standard procedure. However, various problems using FNA compared to core needle biopsy have been reported. Less cell amount, blood and other non tumour tissue aspirated and cells torn out of their environment lead to problems in histological diagnose. The aim of this study was to measure the number of cells harvested by two new needle systems (THYROSAMPLER®) in comparison with the conventional fine needle system (C-FNA). The innovation of the new system is aeration after aspiration by a valve, so that undesired aspiration of blood, debris, and cells from outside the tumour during withdrawal of the needle is minimized.

In a blinded setting, 45 punctures from fresh pig thyroid glands were made and analysed – 15 for each needle (C-FNA, single-needle with air valve T-ONE and multi needle system with air valve T-THREE). The aspirated cell material was evacuated into 10ml cell-culture liquid and calculated according to the manufacturer’s recommendations for the CASY cell counter (CASY® technology, Reutlingen).

With each system, 15 punctures each were aspirated and the cells counted. With the T-ONE System the amount of vital cells was 688%, the amount of total cells 521% higher then using the C-FNA system. With the T-THREE System the amount of vital cells was 901%, the amount of total cells 798% higher then using the C-FNA system.

The mean difference between C-FNA and T-ONE was significant regarding total number of cells (p=0.030) as well as number of vital cells (p=0.032).

The needle systems with the air-valve led to a significantly higher cell amount in needle aspiration biopsy. According to the requirement of cytological diagnosis of soft tissue sarcomas more cell volume could be harvested, which is a well-defined benefit.