The patterns of nerve and associated skeletal injury were reviewed in 84 patients referred to the brachial plexus service who had damage predominantly to the infraclavicular brachial plexus and its branches. Patients fell into four categories: 1. Anterior glenohumeral dislocation (46 cases); 2. ‘Occult’ shoulder dislocation or scapular fracture (17 cases); 3. Humeral neck fracture (11 cases); 4. Arm hyperextension (9 cases). The axillary (38/46) and ulnar (36/46) nerves were most commonly injured as a result of glenohumeral dislocation. The axillary nerve was ruptured in only 2 patients who had suffered high energy trauma. Ulnar nerve recovery was often incomplete. ‘Occult’ dislocation refers to patients who had no recorded shoulder dislocation but the history was suggestive that dislocation had occurred with spontaneous reduction. These patients and those with scapular fractures had a similar pattern of nerve involvement to those with known dislocation, but the axillary nerve was ruptured in 11 of 17 cases. In cases of humeral neck fracture, nerve injury resulted from medial displacement of the humeral shaft. Surgery was performed in 7 cases to reduce and fix the fracture. Arm hyperextension cases were characterised by injury to the musculocutaneous nerve, with the nerve being ruptured in 8 of 9. Five had humeral shaft fracture or elbow dislocation. There was variable involvement of the median and radial nerves, with the ulnar nerve being least affected. Most cases of infraclavicular brachial plexus injury associated with shoulder dislocation can be managed without operation. Early nerve exploration and repair should be considered for:. Axillary nerve palsy without recorded shoulder dislocation or in association with fracture of the scapula. Musculocutaneous nerve palsy with median and/or radial nerve palsy. Urgent operation is necessary for nerve injury resulting from fracture of the humeral neck to relieve ongoing pressure on the nerves

The standard approach is through the deltopectoral interval. Among patients with prior incisions, one makes every effort to either utilise the old incision or to incorporate it into a longer incision that will allow one to approach the deltopectoral interval and retract the deltoid laterally. The deltopectoral interval is most easily developed just distal to the clavicle, where there is a natural infraclavicular triangle of fat that separates the deltoid and pectoralis major muscles even in very scarred or stiff shoulders. Typically, the deltoid is retracted laterally leaving the cephalic vein on the medial aspect of the exposure. The anterior border of the deltoid is mobilised from the clavicle to its insertion on the humerus. The anterior portion of the deltoid insertion together with the more distal periosteum of the humerus may be elevated slightly. The next step is to identify the plane between the conjoined tendon group and the subscapularis muscle. Dissection in this area must be done very carefully due to the close proximity of the neurovascular group, the axillary nerve, and the musculocutaneous nerve. Scar is then released from around the base of the coracoid. The subacromial space is freed of scar and the shoulder is examined for range of motion. Particularly among patients with prior rotator cuff surgery, there may be severe scarring in the subacromial space. Internal rotation of the arm with dissection between the remaining rotator cuff and deltoid is critical to develop this plane. If external rotation is less than 30 degrees, one can consider incising the subscapularis off bone rather than through its tendinous substance. For every 1 cm that the subscapularis is advanced medially, one gains approximately 20 to 30 degrees of external rotation. The rotator interval between the subscapularis and supraspinatus is then incised. This release is then continued inferiorly to incise the inferior shoulder capsule from the neck of the humerus. This is performed by proceeding from anterior to posterior with progressive external rotation of the humerus staying directly on the bone with electrocautery and great care to protect the axillary nerve. The key for glenoid exposure as well as improvement in motion is deltoid mobilization, a large inferior capsular release, aggressive humeral head cut and osteophyte removal