In this study, the investigators are testing a new formulation of lidocaine for its suitability in managing postoperative pain after pelvic (circumcision, inguinal, scrotal), perineal (hemorrhoidectomy) or perianal (fistulotomy) incisions. The new formulation ST-01 is a sustained release lidocaine formulation and is expected to provide pain relief over multiple days. Currently, the drug lidocaine is not available as an injectable slow-release formulation.

The purpose of this study is to find out if a new sustained release lidocaine polymer formulation can provide effective postoperative pain control after surgery and lower opioid consumption.

A single dose of this new formulation ST-01 is administered as peri-neural injection and incisional deposition. The procedure is very comparable to the current standard of care procedure, where lidocaine solution (Lidocaine HCl 1% USP) is administered. However, the polymer solution ST-01 stays in the area of injection longer by forming a soft implant and could provide longer pain control.

The investigators' primary objective is to evaluate the efficacy of an injection of ST-01 to reduce subject-reported postoperative pain after surgery compared to standard of care. Secondary objectives are to determine the safety, frequency and total intake of opioid analgesic medication and frequency and total intake of non-opioid analgesic medication.

The clinical study is conducted at the Vancouver Prostate Centre and St. Paul's Hospital. Potential participants will undergo a screening period and will then be enrolled and randomized to either receive treatment (ST-01) or Control (Standard of Care) after surgery. Up to 120 study subjects will be enrolled and monitored over 30 days after surgery. Subjects will report their postsurgical pain and analgesic medication taken.

The primary endpoint and other continuous secondary endpoints will be compared with independent two-sample t-test if normally distributed and Wilcoxon rank-sum test if not normally distributed.

Inclusion Criteria:

• Any sex, aged ≥ 19 years
• Indication to undergo an operation with a planned pelvic incision
• Able and willing to provide informed consent
• Stated willingness to comply with all study procedures and availability for the duration of the study
• If sexually active, is willing to use adequate birth control methods to prevent pregnancy over the course of the study

Exclusion Criteria:

• History of chronic pain conditions associated with the use of opioids or steroids
• Known allergic reactions to any components of the investigational product
• Active infection involving the surgical site
• Any contraindication to local anesthesia with lidocaine (e.g., known hypersensitivity to anesthetics of the amide type, known hypokalemia, complete heart block, anticoagulants (ASA permitted) antiarrhythmic medication)
• Use of prohibited medications (quinidine, procainamide, disopyramide, lidocaine, mexiletine, flecainide, propafenone, amiodarone, dronedarone, ibutilide, dofetilide, sotalol, vernakalant)
• Has participated in another clinical trial within 3 months prior to the Screening Visit or is planning to participate in another clinical trial during this trial period
• Has any other surgical or medical condition that, in the judgment of the clinical Investigator might warrant exclusion or be contraindicated for safety reason