Could infiltration anesthesia decrease anchor-fixation quality of midurethral slings in the obturator complex?

Single-incision miduretral slings (SIMS) were withdrawn from the market in many countries due to lower efficacy. In some countries they are still in use, preferred primarily because it is possible to perform the procedure under local anesthesia. Based on our previous clinical experience we postulated that local anesthesia decreased primary anchor fixation in the obturator complex. The aim of the study is to assess how local infiltration anesthesia influences anchor fixation of the tape in porcine obturator complex.

The experiment was designed to determine the maximum force necessary to extract an implant anchor from a porcine obturator complex. The implant was extracted at a constant speed and data sampling frequency, and the data on displacement of the testing system, achieved force and time were recorded. The implant arms were divided into groups on the right and left sides. In the first group, the anchored arms were used for two implantations - primary and secondary without infiltration anesthesia - and in the second group they were used in the same way, using infiltration anesthesia.

A total of 40 implanted anchors were tested in the experiment, totaling ten single-incision slings (each anchor was implanted twice). An average of 8.28 N (Newton) (SD 6.73, min. 2.11, max. 30.34 N) is required to remove the implant anchor from the obturator complex without infiltration by local anesthesia. An average force of 4.40 N (SD 2.99 min. 1.2, max. 9.48) is required to remove the anchor from the obturator complex after infiltration. Local anesthesia reduces anchor fixation in the obturator complex by 47%.

The local infiltrative anesthesia decreases anchor fixation in the porcine obturator complex.