Circumcision is a widely performed surgical procedure. For this reason, optimal analgesic management is essential. Loco-regional anesthesia, particularly penile blocks, combined with general anesthesia is the technique of choice for managing analgesia during circumcisions.

Ultrasound is increasingly used in locoregional anesthesia techniques. There is already human research on penile blocks and the use of ultrasound. Studies carried out to date describe an optimization of pain relief in children after circumcision compared with the alternative technique without ultrasound, as well as a reduction in local complications due to injection. However, other studies tend to contradict these findings.

In order to provide additional knowledge and to verify whether ultrasound could provide with more optimal relief after your circumcision, the investigators are carrying out this study.

The investigators are proposing to every patient aged 0 to under 18 who is going to undergo circumcision to take part in this project. A letter is sent to all potential participants no later than 3 days before the operation. Consent can be signed no later than the day of the operation. The cooling-off period is the same regardless of age.

Taking part in the study does not affect the operation in any way. The block will take place in the operating room, prior to surgery.

In this study, participants are randomized into groups. This method is important for obtaining reliable results.

• Group 1 (intervention group): The penile block will be performed using ultrasound.
• Group 2 (control group): The penile block will be performed using anatomical landmarks.

This is a "single-blind" study, which means that only the anaesthetists, investigators and operating room team will be aware of the allocation to one of the two groups.

Data on opiate consumption will be registered as well as the different durations preoperatively, intraoperatively, postoperatively, back in the recovery room and before returning home or any complications as well as pain assessment.

30% of men over the age of fifteen worldwide have had a circumcision according to a World Health Organization report. This operation is common and should not be trivialized. A certain number of surgical complications should be considered, including pain, infections, excessive bleeding or hematomas. Today, the use of opioids as intra- and postoperative analgesics in pediatric urological surgery remains predominant but is the subject of increasing controversies. Indeed, the recent opioid crisis challenges us about their use and highlights their multiple side effects. First of all, their use involves significant risks, including opioid-induced hyperalgesia and potential long-term effects. An increase in pain sensitivity within the 24 postoperative hours being proportional to intraoperative administration of high doses of opioids can be observed. Long-term addiction is also questioned. Then, opioids don't appear to be the most effective per- and postoperative analgesic drug. Its prescription could and should be reduced. In sum, a safe and effective anesthesia is paramount. Use of loco-regional anesthesia (LRA) during pediatric urological surgeries complements general anesthesia and thus offers more optimal postoperative analgesia.

Dorsal penile nerve block (DPNB) is LRA technique of choice for circumcisions and aims to anesthetize both dorsal penile nerves. The name DPNB is used for blocks performed by determining precise dorsal anatomical landmarks and doing two distinct injections. The main complications observed are lesions of the urethra, vascular complications (bleeding from the prepuce; hematomas) and failure of the block. In recent years, Ultrasound (US), a non-irradiating imaging technique widely used in LRA, has been used more and more to perform the DPNB and the procedure is well known and described. A decrease of the amount of opioid analgesics intraoperatively and postoperatively is observed when US is used. Postoperative pain scores are also better. Two methods of DPNB using US exist. In both approaches, probe is placed along the transverse plan. In the first one at the base of penis, with ventral visualization of structures, US-DPNB. In the second method, Reversed Ultrasound-Guided DPNB (RUS-DPNB), the penis is slightly retracted with probe placed dorsally, under the base of penis and above the scrotum. RUS-DPNB method will be used in this study. However, DPNB and RUS-DPNB are well described and used equally in daily practice.

The aim of this prospective study is to compare DPNB and RUS-DPNB in terms of efficacy, using cumulative analgesic dosage in morphine equivalent per kilogram. In the standard practice, the two methods are performed at discretion of every anaesthesiologist at CHUV. In fact, although RUS-DPNB is part of everyday practice at CHUV, it hasn't become the standard method, as the literature has a lack of data to prove its advantage over the standard method, DPNB.

Inclusion Criteria:

• male
• undergoing circumcision
• informed consent

Exclusion Criteria:

• other surgery than circumcision in the same time
• contraindication to local anesthesia
• allergy to bupivacaine
• chronic opiates treatment

males only as it is circumcision

all IPD that underlie results in a publication

Beginning 1 year after publication with no end date

Any researcher or journal contacting the PI with clear and well-founded request