Measurement of tension-free vaginal tape trocar insertion and exit forces.

Background/aims: This study aims to establish a model to measure the forces required for tension-free vaginal tape (TVT) trocar application using a pressure transducer.

Methods: A 3.5 x 3.5 cm pressure transducer was constructed from piezo-resistive material. The transducer digitally recorded the surface contact pressure (pressure = force/area) profile continuously during TVT trocar application. Recordings were successfully obtained from 24 subjects.

Results: The mean (standard error) peak contact pressures during application at the right and left side vaginal walls, and right and left side abdominal walls were 1.05 (0.12) pounds per square inch (psi), 1.08 (0.21) psi, 2.49 (0.3) psi and 2.49 (0.3) psi, respectively. On both the right and left side, pair-wise comparisons between trocar insertion and exit forces were significantly different (p < 0.001).

Conclusion: A model has been developed by which TVT trocar application forces can be objectively measured. The TVT trocar exit force is substantially greater than the insertion force, regardless of side.