The main causes of damage to the brachial plexus at birth are traction, contusion, and compression during delivery.1,2 The residual effects on the arm depend on the number of nerve roots involved and severity of the injury. Babies who have had incomplete or poor function from 6 to 18 months after birth and a greater degree of dysfunction are classified as having moderate to severe damage to the nerves of the plexus.2–4 After the age of 2 years, some degree of residual motor dysfunction may appear. The most common deformity may include all or some of the following: weakness of external rotation, weakness of overhead shoulder movement, scapula instability, subluxation of the humerus, overactivity of the muscles of internal rotation, and weakness of the distal muscles of the forearm and hand.4
Children with brachial plexus injury need to receive optimal therapeutic intervention, with the focus on maximizing function and preventing the development of secondary problems such as shoulder subluxation and tightness. Inferior shoulder subluxation occurs when the head of the humerus slides down or inferior in the glenoid fossa and the scapula is in a downwardly rotated position. The secondary problems can interfere with functional use of the affected upper extremity and the child’s ability to incorporate the arm to perform self-care. Often shoulder supports are placed on the child without a thorough evaluation. An inappropriate shoulder support can contribute to poor alignment of the humerus into the glenoid fossa, which may cause additional impingement and pain.
Children with birth-related brachial plexus often present with shoulder problems.4,5 For implementing an appropriate treatment course, a thorough evaluation is critical. The therapist must assess the alignment of the scapula on the rib cage, the alignment and mobility of the glenohumeral joint, passive and active range of motion, and muscle strength. Subluxation often occurs as a result of the loss of balanced muscle firing around the glenohumeral joint and stretching of the ligamentous support structure.6 The glenohumeral joint must be realigned and is essential for active shoulder movements.
For the adult stroke population there are numerous studies documenting the efficacy in reducing shoulder subluxation with different types of supports for the hemiplegic shoulder.7–9 Zorowitz et al.10 described a comparison study using four different types of shoulder support to optimize function and reduce shoulder subluxation for ambulatory adults with stroke. A humeral cuff sling, a figure-8 strap system with a humeral arm cuff to fit on the affected upper extremity, was found to significantly reduce the vertical asymmetry of the glenohumeral subluxation. The strap and cuff system allows adjustments to the vertical alignment and rotational position of the humerus.10
Brooke et al.11 measured the effects of three different types of shoulder support for shoulder subluxation in adults with hemiplegia: 1) a hemisling device that positions the involved arm in shoulder adduction, elbow flexion, and internal rotation; 2) a figure-8 support that is applied around the uninvolved shoulder (The rationale for this sling is to avoid internal rotation and the flexed arm position of the conventional sling. However, it did not support the humerus into the glenoid fossa); 3) the arm trough, a device that is attached to the arm of the wheelchair (Shoulder subluxation is corrected by adjusting the height of the armrest or position of the trough). The results of that study supported the use of the hemisling. However, the author reported that other factors need to be considered if using the hemisling. There may be risks for contracture secondary to the position of the arm into internal rotation and elbow flexion.11
Children with shoulder girdle weakness may present with potential pain, over-stretching of the joint capsule and ligament, and poor motor control. Limited data exist to support the effectiveness of bracing for children with shoulder subluxation. The primary objective of this case study was to evaluate a custom-fitted, child-size shoulder support that reduced subluxation and maintained alignment through extended periods of the day.
The shoulder support is a brace to be worn directly on the skin to provide maximum support, contour, and comfort. It is made from a Velcro-compatible fabric, which is a knitted unbroken loop backed with a perforated neoprene. The material is custom fit over the involved shoulder with the top of the brace formed at the highest point of the shoulder. The shoulder support consists of a humeral cuff, chest straps, and back strap that supports the scapula and assists with the alignment of the humerus. To stabilize the chest and involved scapula, a contoured chest piece with straps is applied that goes under the axilla of the uninvolved shoulder, across the chest, and is pulled through a D-ring. The straps and cuff system are designed to allow adjustments of both the vertical and rotational position of the humerus (Figures 1–4).
The humeral cuff positions and supports the humerus circumferentially with two straps to pull the humerus in a vertical direction back into alignment with the glenoid fossa. A posterior vertical strap assists with pulling the arm up toward the shoulder with the first Velcro tab applied near the axilla and the second Velcro tab on the high point of the shoulder to assist in stabilizing the humerus (Figure 4). The strap is continued down over the chest on a diagonal toward the opposite underarm. An anterior vertical strap also assists with pulling the arm up toward the shoulder with the first Velcro tab applied near the axilla and the second Velcro tab on the high point of the shoulder. The anterior vertical strap continues down toward the back and is pulled on a diagonal to the opposite underarm.
The subject’s ability to tolerate the brace and alignment must be considered in addition to building a gradual wearing schedule.
The subject was a 9-year-old boy with left congenital brachial plexus from traction applied to his head and neck during the delivery process, resulting in the avulsion of his 4th, 5th, 6th, and 7th cervical nerves. He presented in the outpatient clinic for occupational therapy evaluation with significant wasting and atrophy of the left shoulder girdle. In addition, his left humerus appeared subluxed about 1 inch, sliding down vertically from the glenoid fossa (Figure 5). The medial border of the scapula was winging with the inferior border tipped. His left shoulder was in a forward position with the left scapula slightly elevated in a downward rotated alignment. The humeral head appeared below the inferior lip of the glenoid fossa in an inferior subluxation through clinical palpation. Passive range of motion of his left upper extremity was within functional limits.
He presented with limited scapula and humeral mobility. The strength of the serratus anterior (using a manual muscle test rating of 1 = trace, 2 = poor, 3 = fair, 4 = good, and 5 = normal) was 1/5, upper trapezius 4/5, middle and lower trapezius 1/5, and rhomboids 4/5. The shoulder muscle strength presented with the anterior, middle, and posterior deltoid at 1/5, external rotators 1/5, internal rotator 2/5, and pectoralis major and minor 2/5.
He was able to abduct his arm to 30°, although he also compensated by hyperextending his lower back when attempting to raise his arm. Weak elbow movements were also exhibited with the strength of his elbow flexors and extensors at 2/5. His forearm strength of the supinator and pronators was 4/5, whereas distal control of his wrist and hand also scored a strong 4/5. He demonstrated functional use of his left hand but limited control proximally at the shoulder.
The subject was very active in sports. He participated in soccer during the time of his assessment and stated that he let his left arm hang while running on the field. He reported pain inconsistently around the shoulder area. A shoulder support of some type was discussed that would maintain the integrity of his ligaments around the shoulder girdle and align the humerus into the glenoid fossa. The shoulder brace was especially important for the subject during contact sports, as well as for maintaining alignment during the day.
Three radiographs were taken of both shoulders to quantify and compare the left subluxed shoulder with the unaffected right shoulder:
- Affected shoulder unsupported (Figure 6).
- Shoulder support brace applied (Figure 7).
- After 3 hours of wearing the shoulder support (Figure 8).
The degree of shoulder subluxation found on the radiographs was determined by measuring the vertical and horizontal distances of the glenohumeral axis, as described by Brooke et al.11
The central point of the glenoid fossa was determined by measuring the maximum width and height of the fossa (Figure 9). The point at which these two lines intersect is the central point of this fossa (A). The central point of the humeral head was determined by measuring the greatest width of the humerus and then locating its central point (B). Once these points were defined, the vertical distance was measured by the distance from the inferior part of the acromioclavicular joint and the central point of the humerus (V). The horizontal distance was determined by measuring the distance between the central points (H).
FLOCK OF BIRDS
The subject was evaluated using the Flock of Birds electromagnetic motion capture system (Ascension Technologies, Inc., Burlington, VT) to objectively measure active movement. The Flock of Birds captured whole limb movements during active shoulder flexion and abduction, and elbow flexion. Markers placed at the subject’s thoracic spine (T1 level), humerus, and forearm recorded movement of each segment, and their relative motions revealed joint excursions at the shoulder and elbow. The subject was asked to flex and abduct his humerus with his elbow in an extended position and to flex his elbow. Each of these movements was performed without the shoulder brace and then repeated with the shoulder brace.
Radiographic measurements of the vertical and horizontal alignment of the humerus were taken of the uninvolved and involved left shoulders (Table 1). Initially the patient attempted to lift his involved humeral head actively back into position (25 mm vertical and 32 mm horizontal). It is possible that the clavicle was elevated by the pull of the upper trapezius (4/5 muscle strength) and rhomboids (4/5 muscle strength). The external rotator cuff, middle and lower trapezius, serratus anterior, and the deltoid musculatures were extremely weak, with a strength level of poor to trace. The radiograph demonstrated a superior subluxation of the glenohumeral joint when the humerus moved above the fossa. The patient presented with active motor components of shoulder elevation, minimal shoulder abduction, and internal rotation. This patient typically activated strongly into elevation, causing a superior subluxation position (Figure 6). With the brace in place, the humeral head was positioned back down into the glenoid fossa and both clavicles appeared symmetrical (Figures 7 and 8).
The shoulder brace gave good correction of subluxation as measured in millimeters of the horizontal and vertical distances of the glenohumeral alignment (Table 1). The optimal correction in this case occurred at the vertical component of the glenohumeral alignment. The subluxation was nearly corrected after the immediate application of the brace. Three hours later, the shoulder continued to demonstrate good vertical alignment of the glenohumeral joint.
The motion capture results demonstrated no significant differences in shoulder range of motion between the braced and unbraced conditions. The subject presented poor to trace muscle grade of his deltoid muscles and scapular musculature, which would not have changed with the donning of the shoulder support. However, the brace did not restrict his active range of motion with elbow flexion (Figure 10).
The radiographic results support the use of the shoulder brace to minimize subluxation. The glenohumeral joint must be assessed and realigned before the application of a shoulder support. Because the weight of the dangling arm gives a continuous traction to the cord, relief of the pull can increase circulation, which can reduce the potential for pain.
In addition, over-lengthening of the biceps occurs with poor positioning of the humeral head. The biceps traverse the humeral head, such that subluxation will progressively pull the muscle and decrease the ability over the muscle to contract in optimal length tension. Although the biceps strength is dependent on the innervation, length of the muscle affects the muscle strength. The glenohumeral joint integrity is essential before active shoulder movements can be practiced. Family members or caregivers must be instructed in and be able to demonstrate proper use of the support. The shoulder support must also be accepted by the child.
Careful and thorough evaluation is essential for applying the shoulder support. The goal is to provide optimal musculoskeletal alignment to stabilize the shoulder girdle, and maximize motor return and functional performance. The involved shoulder must feel firmly supported to the child.
Strengthening active elbow range should be encouraged while the humerus and scapula are stabilized by the brace. The elbow joint is an integral part of the upper extremity kinetic chain. The instability around the shoulder area and over-stretching of the tendons that insert into glenoid fossa and coracoid process may lead to substitution patterns and elbow overuse in a poor position.12,13 Major extensors and flexors of the elbow, and the triceps and biceps brachii, originate on the scapula and insert on the ulna and radius, respectively. In the presence of these biarticular muscles, pathological conditions at one joint, in this case the shoulder, affect mechanics at the other. Correction of the shoulder alignment and stability provided by the brace may reduce the biomechanical stress at the elbow during use of the arm and help prevent musculotendinous overload at both the shoulder and elbow. The shoulder support brace can potentially provide the stability and alignment in the shoulder area and provide better stabilization for distal control.
This case study evaluated the efficacy of supporting the subluxed shoulder with a custom-fitted child’s size shoulder support. There are no available shoulder braces for children with subluxation except for the sling support. Radiographic methods were used before application of the shoulder support, immediately after applying the shoulder support, and after 3 hours of wear. This case study suggests that the custom-designed child shoulder support significantly reduced the subluxation and maintained alignment through extended periods of the day. The stability at the shoulder area demonstrated potential for providing improved active control of distal movements at the elbow through an ongoing active exercise program.
This case study suggests, for an active child, the shoulder brace effectively reduced subluxation and maintained current active range of motion for distal control of the arm. There is no absolute evidence that supports reduced long-term shoulder subluxation. More research is needed to critically evaluate the benefits of supports with shoulder subluxation in children for assisting with developing a protocol for correcting shoulder subluxation.
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