Randomizes Control Trial (RCT): Superiority Study on Inter Scalene Block Execution Time for Shoulder Traumatology Surgery and Non-inferiority for Effectiveness Between Two Block Methods: Catheter Over Needle (CON) vs Catheter Through Needle (CTN).
Phase: NA
Conditions: Shoulder Disease
Sponsor: Pontificia Universidad Catolica de Chile

Name of the Study: 
Randomized Control Trial  (RCT): 
Superiority Study for Inter-scalene Block 
Execution Time in Traumatological 
Shoulder Surgery and Non-inferiority for 
Effectiveness between Two Blocking 
Methods: Catheter Over Needle (CON) vs 
Catheter Through Needle (CTN). 
 
NCT: Not Assigned yet 
Date of last review board:  21/09/2022 
 
 
 
 
 
 
 
 
 
 
 

Protocol This clinical trial will be registered on www.clinicaltrials.gov. Upon approval from the 
institutional ethics review committee, the recruitment of 36 patients per group undergoing rotator 
cuff or proximal humerus surgery, who meet the inclusion criteria, do not have exclusion criteria, 
and agree to participate in the study, will be conducted. Informed consent will be obtained, and 
prior randomization generated by a computer program, each patient will be assigned to the 
allocated group: Catheter Through Needle (CTN) or Catheter Over Needle (CON). The inclusion 
criteria will be: age over 18 years, ASA I-III, BMI 18-35 kg/m2. Exclusion criteria will be inability to 
consent to the study, coagulopathy, sepsis, renal or hepatic failure, allergy to local anesthetics, 
previous peripheral nerve damage, and refusal of the postoperative continuous block technique. 
Block execution: After the patients arrive at the operating room, an 18 or 20-gauge intravenous 
Teflon catheter will be placed in the contralateral arm to the operated limb, installed in the 
preoperative unit by the responsible nurse. Monitors will be set up: continuous 3-lead 
electrocardiography, non-invasive ankle pressure, and pulse oximetry. After the safety pause, the 
patient will be premedicated with midazolam 1-4 mg and fentanyl 50-100 mcg. Supplementary 
oxygen will be administered via a Venturi mask at 4 L/min. With the patient in supine and 
semisitting position, an ultrasound-guided inter-scalene block image will be obtained (according to 
the established model for an acceptable injection site) ipsilateral to the surgery, using a linear 
ultrasound transducer of 6-13 MHz (Sonosite). Then, the area will be aseptically prepared with 
chlorhexidine, and local anesthesia will be administered with 2% lidocaine, 3-4 ml. Using a plane 
technique, the Contiplex® C needle set will be used for the CON randomized group, and the 
Contiplex Touhy™ (CT) set for the CTN group. The time in seconds from the start of the puncture 
with both catheters until the application of 3M™ Tegaderm™ dressing for fixation will be timed. All 
blocks will be performed by non-expert residents trained in the use of each needle-catheter set 
and/or by an expert anesthesiologist (in equal proportion in each group). The number of attempts 
or punctures will also be measured, defining each attempt as any reinsertion of the needle through 
the skin once the block has started. After completing the block, the patient will be anesthetized 
with balanced general anesthesia, using Propofol 1-2 mg/kg as an induction agent, fentanyl 3-5 
mcg/kg, neuromuscular relaxation as needed. The airway will be instrumented with a laryngeal 
mask or endotracheal tube at the anesthesiologist's discretion. Ketorolac and paracetamol will be 
used as multimodal analgesia unless contraindicated. Dexamethasone IV and/or ondansetron will 
be used for the prevention of nausea based on classic criteria for preventing postoperative nausea 
and vomiting. Once the surgery is finished, a home analgesia pump (elastomeric pump) will be 
connected to the catheter, and the patient will be educated on the outpatient removal of the 
catheter according to the institutional protocol. Telephone follow-up will be conducted to assess 
pain, complications, the need for urgent oral analgesia, or accidental catheter removal, filling out 
the attached form in the annex. Effective block will be classified as pain on the visual analog scale 
(VAS) equal to or less than 4 out of 10, and accidental removal as displacement of more than 2 cm 
from the fixation point recorded on the anesthesia sheet. The installation times and effectiveness 
of both catheter sets will be compared at 24- 48-72 hours.