MICROTREPHINE FOR TAKING BIOPSIES

Introduction In some diseases of the cornea, histopathological or micr obiological evaluation of a stromal sample is essential. On the other hand one of the main aims in therapy is to keep the cornea clear and w ithout scars. Until now bioptic techniques were not suitable for both aims, getting a sample with minimal damage of the cornea. There was a lack of a method for corneal biopsy which is clinically easily applica ble. Material We developed a new instrument for taking corneal biopsie s. It is a microtrephine with 160 mu m diameter rotating with 30 000 R pm. It takes biopsies of corneal epithelium and stroma as solid cylind ers. The biopsy is non traumatic, safe and repeatable. Biopsies were t aken until now on 32 alkali burnt rabbit corneas, 8 enucleated human c orneas and 5 patients. Results 157 biopsies were taken until now. In 7 5% a sample could be gained. The perforation rate was 0.63% in rabbits . No perforation occurred until now in human corneas. Preparations of light-, scanning- and transmission electron microscopy are presented i n this paper for demonstrating examples of application. Microbiologica l preparations of corneal infiltrates were sterile up to now, represen ting sterile technique with this new instrument. Herpes simplex PCR wa s positive in one out of six stromal biopsies from one cornea in suppo sed herpes keratitis. Conclusion With the microtrephine samples of the corneal stroma can be taken with high precision. A wide variety of ro utine diagnostics including repeated measurements on stromal samples o f a single cornea are possible now. Early bioptic diagnostics of corne al diseases can be achieved now.