A comparison of ultrasound-guided superficial cervical plexus block combined with clavipectoral fascial plane block and blockade of supraclavicular nerves along with upper trunk of brachial plexus The SCUT block in clavicle surgery a single-centre, double-blind, randomized controlled trial

Clavicular fractures are the most common shoulder injuries, particularly among young men, often resulting from sports activities or traffic accidents, especially at the midclavicular region. Surgical treatment offers better functional outcomes, although it carries risks such as nausea, vomiting, aspiration, and laryngeal spasm associated with general anesthesia during endotracheal intubation and extubation. Additionally, the cost of anesthesia adds to the economic burden on patients.

Regional anesthesia has shown to yield superior patient-reported outcomes compared to general anesthesia for upper limb surgery . However, when it comes to clavicle surgery, there is no established site-specific regional anesthesia strategy. Traditionally, a combination of superficial cervical plexus block (SCPB) and interscalene brachial plexus block (ISBPB) has been used to achieve surgical anesthesia. The innervation of the skin above the clavicle by the supraclavicular nerve is well-established. However, the sensory innervation of the clavicle itself remains a subject of controversy. A superficial cervical upper trunck block (SCUTB)  is commonly employed for clavicular fracture surgeries. The brachial plexus, composed of C5-8 and the anterior branch of the T1 spinal nerve, and the cervical plexus, composed of the anterior branch of the deep cervical plexus and superficial cervical plexus, play distinct roles in innervating different structures. The supraclavicular nerve from the superficial cervical plexus is responsible for skin innervation above the clavicle, while the brachial plexus innervates the deep muscles of the clavicle. The combination of SCPB and ISBP effectively addresses the requirements of clavicular fracture surgery, but ISBP carries the risk of complications such as diaphragmatic paralysis resulting from phrenic nerve block.

Sample size is based on duration of motor block in a previous study. The primary outcome of this study is the time to first postoperative analgesia. Based on a review of relevant literature predominantly case reports, a mean difference of 6.9±5.1 hours in the time to first analgesia after the block was observed. With a significance level of 0.05, a minimum of 20 cases in each group, and a power of 0.80, the sample size is determined.

 Study Design and Participants

This study will involve 50 patients classified as American Society of Anesthesiologists (ASA) I-II at our hospital. Hospital ethics committee approval will be obtained and trial will be registered by CTRI. Written informed consent will be obtained from all participants.

The study will enroll patients with unilateral clavicular fractures undergoing elective internal fixation in our hospital. The patients will be randomly assigned to two groups: group I, consisting of patients receiving SCPB and CPB, and group II, comprising patients receiving SCUT block. Each group will contain 25 patients. An anesthesiologist, not involved in the subsequent steps, will recruit patients and determine random grouping using random-number tables. On the day of the operation, a nurse anesthetist, blinded to the study’s scope, will open the envelope, determined the patient’s group, and prepared regional anesthesia drugs. Another anesthesiologist, unaware of the patient’s group allocation, will  perform the regional block. A second nurse anesthetist, blinded to patient group allocation, will assess the scale, record research data, and conduct postoperative follow-up.

 Study Protocol

The surgical procedure involve the patient being brought to the anesthesia preparation room, where a venous channel will be established, and monitoring devices for electrocardiogram, oxygen saturation, and blood pressure will be applied. All blocks will be performed under ultrasound guidance. Patients will be grouped by an anesthesiologist, and the medical staff randomly assigned them to group I (SCPB and CPB) or group II (SCUTB), with the details of group allocation sealed in an envelope. Neither the patient nor the researchers will be aware of the group information. A nurse anesthetist, after obtaining the patient’s consent, will open the envelope and prepared regional block drugs. All regional anesthesia procedures will be conducted by the same anesthesiologist.

 (1) Superficial cervical plexus block (SCPB): The patient will assume a supine position with the head turned contralaterally to ensure adequate exposure of the neck and upper chest. The neck skin will be sterilized with an antiseptic solution. A linear high-frequency ultrasound probe will be placed laterally on the neck, over the midpoint of the sternocleidomastoid muscle, at the level of the cricoid cartilage. The superficial cervical plexus (SCP) will be visualized superficially to the prevertebral fascia, covering the interscalene groove. Using the posterior-in-plane technique, a 5-cm block needle will be inserted from lateral to medial until its tip reached the SCP, located above the prevertebral fascia. After ensuring there is no intravascular placement through careful negative aspiration, 3 mL of 0.5% ropivacaine will be  injected.

 (2) Clavipectoral fascial plane block (CPB): The patient will assume a supine position with the head turned contralaterally, and a small pillow will be placed under the shoulder for support. A local anesthetic solution of 20 mL of 0.5% ropivacaine will be administered. During CPB, the ultrasound probe is placed on both the inner and outer one-third of the clavicle’s anterior surface. Using the in-plane technique, a 22-gauge needle will be inserted in a caudal to cephalad direction into the space between the periosteum of the clavicle and the clavipectoral fascia. A total of 20 mL of 0.5% ropivacaine will be evenly injected, both medially and laterally.

 (3) SCUT Block-  Patients will be placed in a semi-lateral The Modified Bromage Scale (MBS) scores will be used to evaluate upper limb movement function position, with the affected side non-dependent. The SCN will be identified as small hypoechoic cluster, sandwiched between two layers of the deep cervical fascia enclosing the sternocleidomastoid and will be blocked with 3 ml of LA administered.

Systematic UT scanning included identification of the interscalene groove and the ventral rami of the BP which appeared as darkhypoechoic circles within the interscalene groove. About 20 mlof LA will be administered after negative aspiration to the UT.

 An anesthetist, blinded to the patient’s allocation group, will evaluate the scale, record research data, and conduct postoperative follow-up. The effectiveness of the block will be measured at 30 minutes in three areas: the sternoclavicular joint, midclavicular region, and acromioclavicular joint. If the block’s effect is unsatisfactory, the patient will be switched to general anesthesia and withdrawn from the study. At the beginning of the surgery, all patients will be administered 0.05 mg/kg of midazolam and 1µg/kg of fentanyl.

 Inclusion criteria-

Patients classified as American Society of Anesthesiologists (ASA) I-II and Patients with unilateral clavicular fractures undergoing elective internal fixation

 Exclusion criteria

Exclusion criteria included cardio-cerebrovascular diseases, respiratory insufficiency, abnormal blood coagulation, puncture site infection, continuous use of analgesics for the past three months, and allergy to local anesthetics.

 Groups details-

Group I (SCPB and CPB)

Group II (SCUT Block)

 Outcome measures-

As a primary outcome, the effectiveness of the block will be  assessed at 30 minutes in three areas: the sternoclavicular joint, midclavicular region, and acromioclavicular joint. Four levels will be  established: zero indicated no decreased sensation, one indicated decreased sensitivity to puncture, two indicated no sensitivity to puncture, and three indicated no tactile sensitivity. Correct blocks are defined as achieving levels two or three.

. A score of four indicate full muscle strength in relevant muscle groups, three indicate reduced strength but the ability to move against resistance, two indicate the ability to move against gravity but not against resistance, one indicate discrete movements (trembling) of muscle groups, and zero indicate no movement. Visual Analog Scale (VAS) scores will be recorded at 6, 12, and 24 hours after surgery.

The secondary outcome of interest is the time to first use of analgesics. If the postoperative pain score exceeded 4, intravenous administration of 50 mg Tramadol will be initiated.

Diaphragmatic movement will be assessed using real-time M-mode ultrasonography of the hemidiaphragm, with patients examined in an upright seated position. The range of diaphragmatic movement from a resting expiratory position to deep inspiration (sigh test) will be recorded before and 30 minutes after the block, with reductions of more than 75% or no movement considered complete paresis, reductions between 25% and 75% considered partial paresis, and movement less than 25% considered no paresis. Each patient will underwent three pre-block and post-block diaphragmatic movement measurements, with the average scores used.

Block-related adverse effects, such as local anesthetic systemic toxicity, nerve injury, Horner syndrome, pneumothorax, hemothorax, will be recorded.

 Statistical Analysis

Data analysis will be performed using SPSS version 28.0. Normally distributed data will be presented as mean±standard deviation and analyzed using two independent sample t-tests. Count data will be  expressed as percentages (%). Grade data will be  analyzed using the Mann–Whitney U test and presented as median (M) and interquartile range (IQR). A p-value of <0.05 is  considered statistically significant.