Ultrasound guided infraclavicular block has a success rate similar to axillary or supraclavicular approaches,it can be technically challenging due to its depth. Needle visibility can be difficult, even due to its steep angulation, potentially increasing needling time. Superficially and at a distance from the neurovascular bundle, visibility is good, but image attenuation as critical structures are approached may degrade the view. Similarly, the infraclavicular block has advantages over axillary or supraclavicular blocks because it allows catheter placement with Thus, an infraclavicular approach with better needle visibility may be of benefit. The novel retroclavicular block is a variant of the coracoids approach. The needle insertion point is posterior to the clavicle instead of inferior to it. This allows an almost perpendicular alignment of the ultrasound (US) beam and needle shaft. Because the angle of incidence of the US beam is a major determinant of reflection needle visibility is enhanced. If the needle tip is clearly visible, patient safety could be enhanced by avoidance of unintentional contact with the neurovascular bundle. Though few case series have been published using this new retroclavicular approach, no studies have been done comparing it with retroclavicular approach. Hence , we plan to do this single blinded study comparing both these techniques in the following aspects: PRIMARY OUTCOME: 1. Block success rate SECONDARY OUTCOME 1. Needle visibility 2. Time for procedure 3. Patient comfort and satisfaction 4. Axillary artery depth 5. Operator comfort 6. Rate of complications MATERIALS AND METHOD This single blind, prospective study will be done over a period of 1 year, recruiting 30 patients in each group INCLUSION CRITERIA 1. ASA I/ II patients undergoing distal arm, forearm, hand orthopaedic procedures 2. Age: 18-60 years 3. BMI: 18-24 kg/m2 EXCLUSION CRITERIA 1. age less than 18 years, 2. inability to provide informed written consent, 4. refusal of regional anesthesia, 5. Contraindications to regional anesthesia (local skin infection, coagulopathy, shoulder or upper chest deformity, 6. severe respiratory disease, 7. preexisting neurological deficit in the ipsilateral arm, 8. known allergy to local anesthetics On arrival in the induction room, standard ASA monitoring will be applied and a 20-gauge intravenous catheter be inserted in the controlateral arm. Intravenous midazolam 1 to 2 mg will be given based on patient preference. The patients will be given infraclavicular block according to computer generated random numbers by either of the two techniques. CLASSICAL CORACOID APPROACH The patient will then placed in a supine position, with the torso elevated to about 30 degrees and head facing away. A high-frequency linear US probe (6–15 Hz Sonosite Turbo M) will be placed parasagittally just medial to the coracoids process and caudal from the clavicle. Short-axis visualization of the axillary vessels and of the cords will then obtained by the coracoid approach. At this time, the lung and second rib will also be visualized. At this point, needle will be inserted cranial to the probe and using the in plane technique 20 cc of 0.5% levobupivicaine will be deposited around the axillary artery in a U shaped fashion. RETROCLAVICULAR TECHNIQUE The patient will then placed in a supine position, with the torso elevated to about 30 degrees and head facing away. A high-frequency linear US probe (6–15 Hz Sonosite Turbo M) will be placed parasagittally just medial to the coracoids process and caudal from the clavicle. Short-axis visualization of the axillary vessels and of the cords will then obtained by the coracoid approach. At this time, the lung and second rib will also be visualized. While holding the probe, the needle insertion point will be found by palpating the supraclavicular fossa, just medial to the shoulder at a point sufficiently posterior to the clavicle (generally 1–2 cm depending on morphology) and medial to the trapezius muscle insertion point on the clavicle (Fig. 1). If the fossa is depressible, the insertion point was sometimes found needle will need to clear the clavicle and stay parallel to the US probe to avoid any posterior angling. From this finger position, probe rotation and alignment with the palpating finger will be perfectly achieved while keeping the axillary vessels in the short axis. Once probe rotation achieves finger-probe alignment, the needle will now aim more toward the anterior axillary line than with the classic coracoid approach. The probe will then applied using a sterile technique and, after local skin anesthesia, a 100-mm 18-gauge echogenic needle (PajunkMedizintechnik, Geisingen, Germany) will be inserted and advanced at an angle strictly parallel to the probe and strictly in-plane. An initial blind zone measuring 3 to 4 cm in general, which corresponds to the acoustic shadow of the clavicle, was first passed through. For safety purposes, this length will be evaluated by checking the surface distance between the probe and initial insertion point. Once the blind zone is crossed, correct in-plane alignment should enable a precise view of the needle shaft and, most importantly, the tip as it advances toward the neurovascular bundle. If the initial puncture point is correct and the angle of penetration is parallel to the US probe, the shaft should point to the posterior wall of the axillary artery. Hydrodissection will be used for the safe and efficient injection of the local anesthetic bolus posterior to the axillary artery. Twenty milliliters of levobupivicaine 0.5% will be injected incrementally, slightly adjusting the needle tip to obtain a U-shaped distribution of local anesthetic around the axillary artery. Blocks will be performed by anesthesiologists experienced in US-guided regional anesthesia. Immediately after block completion, patients will be asked to rate their discomfort associated with the procedure using a 10-cm visual analog scale (0 = no pain, 10 = worst pain imaginable). Block assessment will be performed by an independent research assistant 10, 20, and 30 minutes after the bolus is completed. Sensory loss will be assessed in the territory of the radial (lateral aspect of the dorsum of the hand), median (volar aspect of the thumb), ulnar (volar aspect of the fifth finger), musculocutaneous (lateral aspect of the forearm), and medial cutaneous nerve of the forearm (medial aspect of the forearm) distributions using a 3-point score, where 0 = normal sensation, 1 = diminished sensation to pinprick (hypoesthesia), and 2 = loss of sensation to pinprick (analgesia).Motor function will also tested (0 = normal strength, 1 = weakness, 2 = paralysis) for the radial (thumb abduction), median (thumb opposition), ulnar (thumb adduction), and musculocutaneous (elbow flexion) nerves. Block success will be defined as a sensory score of 10 at 30 minutes. Needling time will be defined as the time from the beginning of skin anesthesia until the end of levobupivicaine injection. Procedures will be videotaped and reviewed after study completion by 2 independent anesthesiologists skilled in US-guided regional anesthesia using a 5-point Likert scale to rate needle visibility (1 = very poor, 2 = poor, 3 = fair, 4 = good, 5 = very good) and to record the depth of the axillary artery. Also noted will be the incidence of needle-induced paresthesia, vascular puncture, Horner syndrome, dyspnea, and symptoms of local anesthetic toxicity. To rule out pneumothorax, every patient will have posteroanterior and lateral chest x-ray before discharge, which will be read by an independent radiologist. 48 hours after the surgery the patients were asked to rate their satisfaction with the anesthesia experience on a 10-point scale (0 = totally unsatisfied, 10 = totally satisfied) and were questioned about possible complications (eg, residual paresthesia, hematoma, signs of infection, dyspnea). PROFORMA Name: age: sex: IP no BMI: Surgery: 1. block successful: 2. needling time: 3. operator satisfaction: 4. surgeons satisfaction 5. patients satisfaction 6. needle visibility: 7. axillary artery depth 8. complications: dyspnoea/ pneumothorax/ vessel puncture |