Effect of vitrectomy and cytopreparatory techniques on cell survival and preservation

Obtaining vitreous fluid by means of vitrectomy frequently results in a specimen that is difficult to assess cytologically. We devised an experimental model to examine the effect of the vitrector on human leukemic cancer (HL60) cells in suspension and to evaluate the cytopreparatory techniques of membrane filtration and cytocentrifugation. Eighteen 3-mL specimens of cells at concentrations ranging from 1 to 9 x 10(5)/mL were vitrectomized, and eighteen 3-mL control samples matched for cell concentration were obtained atraumatically. No significant difference in cell loss, as determined by means of staining with nigrosin vital dye, was found at any cell concentration between the vitrectomized and control specimens. The specimens were then processed cytologically. On cytologic assessment it was not possible to distinguish the vitrectomized and control specimens. A higher degree of cell preservation was noted at higher cell concentrations regardless of the cytopreparatory technique, but at lower concentrations membrane filtration resulted in a higher proportion of cytologically assessable specimens than did cytocentrifugation (42% vs. 22%). The results suggest that the vitrector causes minimal cellular damage and that to obtain optimal results both cytopreparatory techniques should be used with all vitrectomy specimens.