Serratus Anterior Plane Block for Modified Radical Mastectomy: Double-point VS Single-point

Study Overview
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Brief Summary
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Nowadays, the incidence of breast cancer is the first number of malignant tumors, and the primary treatment method is surgery. As is known to all, less postoperative complications and enhanced recovery are closely related to effective analgesia. However, postoperative patients often experience moderate pain, while associated with axillary discomfort. Serratus Anterior Plane Block (SAPB) relieves postoperative pain, but traditional single point block method has no effect on axillary discomfort. Therefore, it is necessary to try double point blocks to explore their impact on postoperative analgesia and axillary comfort. This RCT will recruit patients proposed to undergo Modified Radical Mastectomy (MRM) and be randomized to single point or double point groups to evaluate their postoperative pain score and axillary comfort in order to provide clinical guidance.

Detailed Description
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The conventional SAPB, which often performs single point block from the level of the fifth rib, does not completely relieve postoperative pain in patients with axillary lymph node dissection, probably due to insufficient range of local anesthetic diffusion.Anatomical study indicated that with a double point SAPB at the third and fifth rib levels, respectively, the local anesthetic diffusion range can reach the axillary level and may provide better analgesic effects. However, the support of clinical data is lacking.Therefore, the hypothesis of this study is that double point SAPB will provide better postoperative analgesia compared with conventional single point SAPB in patients undergoing modified radical mastectomy.This study will include 60 patients proposed to undergo modified radical mastectomy, allocated to the Double-point or Single-point group in a 1:1 ratio, randomly.The Double-point group will perform a double point SAPB, which is a combined block at the third and fifth rib levels, respectively.The Single-point group will undergo a single point SAPB, traditionally performed at the level of the fifth rib.Observation outcomes included changes in blood pressure and heart rate during dissection of skin and dissection of axillary lymph nodes, postoperative pain scores, axillary comfort, recovery quality, and related complications and postoperative hospital stay.Therefore, the objective is to investigate whether this simple technical modification can better reduce postoperative pain and promote rehabilitation in patients with modified radical mastectomy.

Official Title
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The Analgesic Effect of Ultrasound-guided Double-point Versus Single-point Serratus Anterior Plane Block on Modified Radical Mastectomy：A Randomized Controlled Study

Conditions
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Mammary Cancer, Serratus Anterior Plane Block, Postoperative Pain

Intervention / Treatment
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* Procedure: Double-point SAPB
* Procedure: Single-point SAPB


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients are proposed to undergo Modified Radical Mastectomy Patients with American Society of Anesthesiologists (ASA) physical status I III aged 18-70 years BMI ≤ 35 kg/m2 Exclusion Criteria: Patients with a pre-existing neuropathy or sensory deficit affecting the operative region Pregnancy Chronic pain or opioid dependence (at least 30 mg of oxycodone or equivalent per day) Allergy to local anaesthesia or any component of the proposed multimodal analgesia regimen Local or systemic contra-indications to peripheral nerve blocks (local infection at the puncture site, coagulopathy, platelets less than 80*10^9/L and prothrombin time more than 15 s)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Double-point SAPB<br>SAPB will be performed simultaneously in both the third and fifth rib levels. | Procedure: Double-point SAPB<br>* A high-frequency linear probe (6-13 MHz) of the ultrasound machine was used to identify the fifth rib in the midaxillary line. The anatomic landmarks of the block were identified: latissimus dorsi, serratus anterior, and the intercostal muscles in the fourth and fifth intercostal levels. After sterilization and draping, an 20-gauge needle was introduced craniocaudally using an in-plane technique. The needle tip was advanced, targeting the plane between the serratus anterior muscle and the fifth rib. Needle position was confirmed by injection of 1-to-2 mL of saline after negative aspiration. And use the same method targeting the plane between the serratus anterior muscle and the third rib.Under real-time visualization, total 30 mL of 0.375% ropivacaine and 0.5 μ g/kg dexmedetomidine mixture will be injected into the two points with 15 ml separately.<br>|
| Experimental: Single-point SAPB<br>SAPB will be performed only in the fifth rib level. | Procedure: Single-point SAPB<br>* A high-frequency linear probe (6-13 MHz) of the ultrasound machine was used to identify the fifth rib in the midaxillary line. The anatomic landmarks of the block were identified: latissimus dorsi, serratus anterior, and the intercostal muscles in the fourth and fifth intercostal levels. After sterilization and draping, an 20-gauge needle was introduced craniocaudally using an in-plane technique. The needle tip was advanced, targeting the plane between the serratus anterior muscle and the fifth rib. Needle position was confirmed by injection of 1-to-2 mL of saline after negative aspiration.Under real-time visualization, total 30 mL of 0.375% ropivacaine and 0.5μ g/kg dexmedetomidine mixture will be injected.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative pain severity at 24 h | Postoperative pain severity at rest and movement measured using a numerical rating scale(NRS) at 24 h. The numerical rating scale (NRS) is a line with numbers from 0 to 10 are spaced evenly across the page. And the NRS is bounded at the left-most end with no pain and at the right-most end with worst pain imaginable. Patients are instructed to circle the number that represents the amount of pain that they are experiencing at the time of the evaluation. The movement status refers to maximum mobility of the upper arm of the surgical side. | 24 hours after the surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain severity at discharge from PACU and at 6 and 12 and 48 h postoperatively | Secondary analgesic outcomes included: pain severity at rest and movement measured using a NRS at discharge from PACU and at 6 and 12 and 48 h postoperatively; | Respectively at discharge from PACU and at 6 and 12 and 48 h after the surgery; | 
| Postoperative opioid consumption | At the end of surgery, patients use postoperative controlled analgesia pump, equip with 0.75 μg / ml sufentanil without background dose, locking time is 10min, and each controlled dose is 2 ml. The cumulative amount of sufentanil used at 24 and 48 hours after surgery will be recorded separately. | Respectively at 24 and 48 h after the surgery; | 
| Proportion of rescue analgesia | Rescue analgesia was started when NRS ≥ 4, with Flurbiprofen Axetil 50mg i. v. The proportion of patients who required at least one rescue analgesia at 48 hours after surgery will be recorded. | 48 h after the surgery; | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Mammary Cancer, Serratus Anterior Plane Block, Postoperative Pain, Axillary Discomfort