The Accuracy of Large Loop Excision of the Transformation Zone Specimen Dimensions in Determining Volume: A Multicentric Prospective Observational Study.

OBJECTIVE: The aim of the study was to determine which mathematical formula of specimen dimensions is the most accurate method of determining volume of the excised specimen at loop excision of the transformation zone. MATERIALS AND METHODS: A multicenter prospective observational study was conducted. A total of 258 patients who had a loop excision of the transformation zone performed as treatment of cervical intraepithelial neoplasia 2-3 were included. The dimensions and the volume of the specimen were measured at the time of the procedure, before formaldehyde fixation. The volume was measured by immersing the specimen in a graduated cylinder using Archimedes fluid displacement technique. The measured volume was compared with the calculated volume using different volume formulas, that is, a cone, a cylinder, a parallelepiped, and a hemiellipsoid. The main outcome measure was the relationship between calculated volume (using the dimensions of thickness, length, and circumference) and the measured volume of the specimen. RESULTS: The mean (SD) thickness, length, and circumference of specimens were 8.8 mm (3.8), 12.7 mm (5.9), and 45.7 mm (16.8), respectively. The mean (SD) measured volume was 2.53 (1.49) mL. Using the formula for the volume of a cone, a cylinder, a parallelepiped and a hemiellipsoid, estimated volumes were 1.03 mL (1.22), 3.10 mL (3.65), 6.20 mL (7.31), and 2.07 mL (2.44), respectively. The highest intraclass correlation coefficient between measured and calculated volume was observed when using the formula for the volume of a hemiellipsoid specimen (0.47, 95% CI = 0.36-0.56). CONCLUSIONS: The hemiellipsoid formula is the most accurate determinant of the excised volume. Other formulas do not allow for an accurate estimation of the excised volume.

Benefits of Direct Colposcopic Vision for Optimal LLETZ Procedure: A Prospective Multicenter Study.

OBJECTIVE: The aim of the study was to assess whether direct colposcopic vision (DCV) of the cervix during large loop excision of the transformation zone (LLETZ) is associated with a decrease in the volume and dimensions of specimens or affects margin status at histology. MATERIALS AND METHODS: A prospective multicenter observational study of 216 women who underwent LLETZ for grades 2 and 3 cervical intraepithelial neoplasia was conducted. The volume and dimensions (circumference, length, and thickness) of the surgical specimens were measured before fixation. Data were compared according to the use of colposcopy during LLETZ. The following 3 groups were considered: LLETZ performed without colposcopy (n = 91), LLETZ performed immediately after colposcopy (n = 51), and LLETZ performed under DCV (n = 74). RESULTS: Patient characteristics were comparable with regard to age, parity, history of excision, indication of the procedure, and the size of the cervix. We found a significant decrease in all dimensions of the specimens obtained under DCV (p < .001). Margin status was not affected. After adjusting for confounders, the mean volumes were significantly lower in the DCV group (adjusted mean difference = -0.66 mL; 95% CI = -1.17 to -0.14). The probability that negative margins would be achieved together with the attainment of a volume less than 5 mL and a thickness less than 10 mm was the highest in the DCV group (adjusted OR = 2.80; 95% CI = 1.13 to 6.90). CONCLUSIONS: Direct colposcopic vision is associated with a significant decrease in the volume and in all dimensions of LLETZ specimens with no compromise in the margin status.