The Impact of Retropubic Lidocaine vs Saline on Postoperative Urinary Retention Following Midurethral Sling

One of the most commonly used local anesthetic agents in surgical practice is lidocaine. Lidocaine as a local anesthetic is characterized by a rapid onset of action (typically within 2-5 minutes of injection) and intermediate duration of efficacy and thus is often favored in the outpatient setting for pre-incisional injections. Of note, however, its effects general only last up to 2 hours. Epinephrine (adrenaline) vasoconstricts arteries, delaying the resorption of lidocaine, and thus almost doubles the duration of anesthesia.

Several mechanisms could explain the inability to void postoperatively, including nerve conduction impairment from anesthesia. Multiple studies have investigated the use of various types of anesthesia and downstream effects on postoperative urinary retention. It is postulated that denervating the regional pelvic nerves for pain control may lead to denervation of the bladder for a transient period of time, block both the afferent and efferent pathways of the voiding mechanism, affect the urethral retro-resistance pressure and impact urethral length thereby contributing to voiding dysfunction postoperatively. The use of normal saline in this setting may have a reduction in rates and duration of postoperative urinary retention following retropubic midurethral sling placement.