Aim of the study is to investigate the efficacy and safety of continuous ESP block in children under the age of 10 yrs undergoing video-assisted thoracoscopic procedures, compared to Thoracic Epidural Anesthesia (TEA).

Primary outcome:

Post-operative pain assessed by FLACC (Face, Legs, Activity: Cry, Consolability) for children age 1-5 years, and NRS (numerical rating scale) for children age 6-10 years

Secondary outcomes:

• Opioid consumption for 48 hours post-operatively.
• Intraoperative opiod use
• Block failure rate (defined as Heart Rate (HR) increase of more than 20% of baseline at surgical incision)
• Time to extubation after surgery completion After parental consent, children aged 0-10 yrs scheduled for unilateral VATS procedure will be randomized into two groups: Thoracic Epidural Group (TEA) vs Erector Spinae Plane block (ESP).

Children with history of allergy to local anesthetics, systemic coagulopathy, infection at site of puncture, severe renal or liver disease, known rib cage malformations will be excluded from the study.

Anesthesia will be induced at operator's preference; before surgery beginning children will be positioned and either TEA or ESP will be performed. In both cases, a bolus of of 0.3-0.5ml/kg of 0.2% ropivacaine will be administered, followed by an infusion of 0.2mg/kg/hr for the next 48 hours. The time from block placement to incision will be recorded, change in HR before and after incision will be documented, need for intraoperative opiod use, time to first rescue analgesic, and total amount of local anesthetic given at 24 h and 48 h post-operatively will be recorded together with pain measures as specified. Opiods will be prescribed if child presents with FLACC scores > 3 (FLACC score of 0-3 = mild pain, 4-6 = moderate, 7-10 = severe), or VAS >5.

Total opioid consumption will be recorded.

Statistical analysis

Intention to treat analysis will be performed. Quantitative variables will be described as mean and standard deviation (sd) or median and interquartile range (IQR) if not normally distributed (Shapiro-Wilks test) For primary outcome, VAS or FLACC score will be compared with t-test or Mann-Whitney test Opioid consumption will be compared with t-test or Mann-Whitney test Block failure rate will be compared with chi2 test Time to extubation will be compared with log rank test

Sample size With 37 patients for group a power of 80% will be achieved to identify as significant a difference in mean pain score when sd is 1,5 times greater than mean. Alpha error will be 0.05 and a two-sample t-test will be applied.

Randomization A random block centralized randomization list will be generated before study start with Ralloc command in Stata. It will be stratified by center. To avoid allocation concealment the closed envelope method will be used.

Inclusion Criteria:

• ASA I-III
• Scheduled for Video-Assisted Thoracoscopic Procedure
• Parental consent

Exclusion Criteria:

• Parental refusal
• History of allergy to local anesthetics
• Systemic coagulopathy
• Local infection at puncture site
• Severe renal or liver disease
• Known rib cage malformations