Effectiveness of Field Block Compared With Interscalene Block in Shoulder Surgery

Clalit Health Services

Status: Enrolling

Conditions: Regional Anesthesia Techniques in Shoulder Surgery

Treatments: Procedure: Shoulder Field Block by Orthopedic Surgeon; Procedure: Interscalene brachial plexus block and superficial cervical plexus block

Study type: Interventional

Funder types: Other

Identifiers

NCT07173894

HASH-ORTHO-FBvsISB-2025

Details and patient eligibility

About

This study will compare two different types of anesthesia used for shoulder surgery. The first method, called an interscalene block, is commonly performed by anesthesiologists and is effective for pain control but may cause side effects such as breathing problems, arm weakness, or discomfort. The second method, called a shoulder field block, is a newer technique performed by orthopedic surgeons that numbs the nerves around the shoulder without affecting breathing.

Patients scheduled for shoulder surgery will be randomly assigned to receive either the interscalene block or the shoulder field block. The main goal of the study is to find out whether the shoulder field block provides pain relief that is as effective as the interscalene block, but with fewer side effects.

Pain levels, patient satisfaction, length of hospital stay, need for pain medication, and any complications will be recorded and compared between the two groups. The results may help identify a safe and effective alternative anesthesia option for patients undergoing shoulder surgery.

Full description

Regional anesthesia is widely used for shoulder surgery, most commonly with an interscalene brachial plexus block (ISB). While ISB provides effective pain relief, it is associated with side effects such as hemidiaphragmatic paralysis, breathing difficulties, Horner's syndrome, nerve injury, and rebound pain. These risks limit its use in patients with respiratory conditions, obesity, or other contraindications.

A shoulder field block (FB) is a newer approach that targets the suprascapular, axillary, and lateral pectoral nerves, which supply most of the sensation to the shoulder joint. Unlike ISB, the field block does not affect the phrenic nerve, making it a potentially safer option. Cadaveric and early clinical studies suggest that field blocks may provide effective pain relief with fewer complications, but direct comparisons with ISB in surgical patients are limited.

This randomized controlled trial will enroll 64 adult patients undergoing arthroscopic or open shoulder surgery. Patients will be randomized into two groups:

Field Block Group: Local anesthesia field block performed by an orthopedic surgeon using anatomical landmarks.

Interscalene Block Group: Standard interscalene block performed by an anesthesiologist.

The primary outcome will be postoperative pain intensity measured by a numerical rating scale (0-10) at multiple time points during the first 48 hours. Secondary outcomes include patient satisfaction, hospital length of stay, opioid consumption, complications, and unplanned medical visits due to pain.

The study hypothesis is that a shoulder field block will provide pain relief that is non-inferior to an interscalene block, while reducing side effects and improving patient satisfaction. If effective, this technique could offer a practical alternative that can be safely performed by orthopedic surgeons, expanding anesthesia options for shoulder surgery patients.

Enrollment: 64 estimated patients

Sex: All

Ages: 18 to 75 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Age between 18 and 75 years
• Scheduled for arthroscopic or open shoulder surgery

Exclusion criteria

• Prior surgery or trauma to the shoulder
• Revision shoulder surgery
• Fibromyalgia
• Pregnancy
• Contraindications to regional anesthesia (e.g., allergy to local anesthetics, coagulopathy, local site infection)
• Preexisting neuropathy or myopathy of the surgical limb
• History of chronic opioid use
• Cognitive impairment or inability to understand pain scoring systems (e.g., dementia)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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64 participants in 2 patient groups

Shoulder Field Block by Orthopedic Surgeon

Experimental group

Description:

Participants in this arm will receive a shoulder field block performed by the orthopedic surgeon using anatomical landmarks after induction of general anesthesia. The block targets the suprascapular, axillary, and lateral pectoral nerves using a tumescent local anesthetic mixture of lidocaine with epinephrine, bupivacaine, and saline to provide intraoperative and postoperative analgesia. This novel technique aims to provide effective pain relief with fewer side effects compared to the standard interscalene brachial plexus block.

Treatment:

Procedure: Shoulder Field Block by Orthopedic Surgeon

Interscalene Block by Anesthesiologist

Active Comparator group

Description:

Participants in this arm will receive a standard interscalene brachial plexus block performed by an anesthesiologist under ultrasound guidance before surgery. This block anesthetizes the upper brachial plexus nerves to provide effective intraoperative and postoperative analgesia for shoulder surgery. It is the current standard of care but may be associated with side effects such as diaphragmatic paralysis and arm weakness.

Treatment:

Procedure: Interscalene brachial plexus block and superficial cervical plexus block