Rotary biopsy forceps

Abstract

Pulling tissue away from the gut wall affects the surrounding mucosa, which may be pulled and torn, and the specimen taken is small compared with the extent of the injury to the gut wall. A larger cup size permits larger specimens; although when a specimen is taken by pulling with large cups, there is a greater likelihood of bleeding. We have developed a rotary biopsy forceps with which it is possible to take a larger amount of tissue more reliably, and with less injury to the gut wall (figure). To evaluate the usefulness of these forceps, biopsy specimens of colonic mucosa were taken from ten healthy men (the authors and doctors in our department) with conventional and rotary forceps with the same size cup. Two specimens were taken from each person, and the size of the injured area was compared in ten pairs of specimens. To keep the distance between the endoscope tip and the biopsied area constant, a cap was mounted at the tip of the endoscope, and to prevent the biopsied area from being tilted, a photograph was taken while the cap was in contact with the mucosa. All biopsy specimens were weighed immediately using an electronic balance (accuracy 0·1 mg). Each specimen was weighed twice. The size of the injured area was 8·6 (SD 1·4) mm with rotary forceps; significantly smaller than the size of the injured area (15·6 [2·7] mm) by conventional forceps (p<0·05). With rotary forceps, it was possible to reduce the injured area by 55·1% (range: 43·6–71·3%) compared with conventional forceps. Mean weight of the specimens taken by the conventional forceps was 17·3 (2·6) mg, significantly lighter (p 0·05) than that of the specimens taken by rotary forceps (22·5[1·3] mg). Increased weight ratio ([weight of specimen from rotary forceps/weight of specimen from conventional forceps] 100%) of each of the pairs was 116–146%. Biopsy specimens were fixed and stained; those taken by rotary forceps showed no histological damage.