Comparing tissue coring potentials of hollow needles without stylet and caudal needles with stylet: an experimental study

Abstract

Background and objectives: Although the association of tissue coring and development of epidermoid turnout has been proposed, the extent and frequency of such coring is still controversial and the viability of carried cells has not been substantiated. In the present study, we used an experimental model without needle removal to investigate the incidence of tissue coring using two different needle types. Methods: We inserted 22-G caudal (n = 34) or 22-G hollow (n = 25) needles to the tumour-free areas of fresh modified mastectomy specimens. The specimen was stretched and needles were inserted perpendicular to the skin and forced to penetrate the full thickness of the specimen. Without removing the needle, the needle cavity was then washed with 2 mL of RPMI 1640 with L-Glutamine and the washings were collected in a 15-mL falcon tube. The tubes were sealed and labelled and processed to obtain cytologic preparations. The slides were evaluated under a light microscope. Results: A high rate of epithelial cell transportation was noted. All the carried cells were stratum corneum cells with no nucleus. No nucleated cells were seen. The incidence of carried cells was 64.7% and 72.0% in the caudal and hollow needle groups, respectively (P > 0.05). Conclusion: Only cells from the outermost layer, stratum corneum, which is made of dead flat skin cells, were transported with needle puncture. The risk of epidermoid turnout development after regional anaesthesia must therefore be low. The incidence of transporting non-nucleated stratum corneum cells was similar between hollow and caudal needles.