Randomized, multi-center, double-blind, two-armed, parallel active groups, prospective trial, to evaluate, in pediatric population undergoing Flat Foot surgery or Inguinal hernia repair, the efficacy and safety of chloroprocaine 1% and 2% for peripheral nerve block (PNB) based on concentration-response relationships. The present protocol is part of an extensive Pediatric Investigational Plan (PIP) which has been submitted to the Paediatric Committee (PDCO) of the European Medicine Agency (EMA)in the contest of the marketing authorization application of chloroprocaine use for perineural block. The PDCO has adopted a positive opinion on both the PIP and the present clinical protocol.

Chloroprocaine Hydrochloride 1% Sintetica is currently marketed in 9 European countries as intrathecal (spinal) anesthetic in adults where the planned surgical procedure is not expected to exceed 40 minutes. Since 2015, the Marketing Authorization in Switzerland has been extended to chloroprocaine HCl 20 mg/mL and 30 mg/mL solutions for injection, for local anesthesia by infiltration, for PNB and epidural block, respectively. Regional analgesia, and specifically PNB, is an acceptable means of providing intraoperative anesthesia and postoperative analgesia in neonates, infants, and children while decreasing the use of systemic opioids and avoiding opioid-related adverse effects. With the advent of ultrasound and improvements in equipment in the last decade, the utilization of PNB in children has increased tremendously.

Flat Foot and inguinal hernia repair have been considered the ideal surgeries for testing the clinical efficacy and safety of chloroprocaine since they are short procedures with low postoperative pain that only require a short- to intermediate-acting agent. The study consists of a treatment period of 1 day and of a single perineural injection, administered through ultrasound-guided technique in order to avoid the risk of chloroprocaine IV injection. A total of 174 (87 per treatment group, allocated to 1% or 2% arm in a ratio of 1:1) male and female paediatric patients (age range from birth to <18 years) undergoing Flat Foot surgery or Inguinal hernia repair, planned for peripheral nerve block anaesthesia and equally distributed within the two surgical procedures.

• Hernia, Inguinal
• Flat Foot

• Drug: Chloroprocaine 1% Injectable Solution
  All the eligible patients will be administrated by Chloroprocaine 1 % according to the randomization criteria.
  Other Name: ARM 1
• Drug: Chloroprocaine 2% Injectable Solution
  All the eligible patients will be administrated by Chloroprocaine 1 % according to the randomization criteria.
  Other Name: ARM 2

• Experimental: Chloroprocaine 1%
  All the eligible patients will be administrated by Chloroprocaine 1 % according to the randomization criteria.
  Intervention: Drug: Chloroprocaine 1% Injectable Solution
• Experimental: Chloroprocaine 2%
  All the eligible patients will be administrated by Chloroprocaine 2 % according to the randomization criteria.
  Intervention: Drug: Chloroprocaine 2% Injectable Solution

Inclusion Criteria:

1. Male and female paediatric patients from birth to <18 years scheduled for:

   • Flat Foot surgery (6 to <18 years; children and adolescents)planned for sciatic nerve block short-lasting anaesthesia,
   • inguinal hernia repair (0 to 6 years; newborn infants, infants-toddlers and children)planned for ilioinguinal/iliohypogastric block short-lasting anaesthesia;
2. Normally active and otherwise judged to be in good health on the basis of medical history, physical examination, with normal lean body mass (BMI18,5 - 24,9 Kg/m2 inclusive) and normal body development (normal weight and height according to local paediatric Height and Weight Chart);
3. ASA I and ASA II patients;
4. Written informed consent provided by parents/tutor, willing and able to understand the purpose of the study, including possible risks and side effects, and willing and able to comply, on their behalf and of the minor, with the study requirements;
5. Willing and able to give additional written informed consent by itself, in case of children and adolescents, in addition to parents/tutor;
6. Willing and able, in case of children and adolescents, to comply with the study requirements on their behalf.

Exclusion Criteria:

1. ASA > II patients;
2. Preexistent infection at injection site;
3. Use of opioids, antidepressants, anticonvulsant, sulfonamide, vasopressors, ergot-type oxytocic drug and mixtures of local anaesthetics, antiarrhythmic drug class III, such as amiodarone, strong inhibitors of CYP1A2, such as fluvoxamine and enoxacin;
4. Use of medication(s) known to interfere with the extent of regional blocks for 2 weeks before the start of the study;
5. History of drug or alcohol abuse;
6. Sensitivity among the study medication active ingredient, the members of the PABA esters group and amides-type local anesthetic group;
7. Clinical history of allergy, hypersensitivity or intolerance to the study medication or other medications used during surgery;
8. Pregnancy and lactation: positive pregnancy test at screening (if applicable), pregnant or lactating (the pregnancy test will be performed to all fertile subset);
9. Participation in any other clinical study within the 3 months prior to the screening.