Shoulder sequelae in children with brachial plexus palsy





Summary box




  • 1

    Despite advances in prenatal and obstetrical care, the estimated prevalence of brachial plexus palsy (BPP) remains stable.


  • 2

    The goal in the infant is to maintain joint motion and to keep the shoulder reduced during the period of reinnervation.


  • 3

    The modified Mallet scale is the most commonly used assessment of shoulder function in children with BPP Brachial Plexus Palsy.


  • 4

    Children with incomplete recovery following brachial plexus palsy may have functional limitations because of muscle weakness and soft tissue contractures, particularly around the shoulder and elbow.


  • 5

    Internal rotation contracture of the shoulder is most common in children with incomplete recovery. Long standing muscle imbalance results in progressive glenohumeral deformity.


  • 6

    The most salient clinical finding is loss of passive shoulder external rotation between examinations. Loss of passive external rotation is a useful guide for proceeding with additional imaging and potentially surgical intervention.


  • 7

    MRI appears to be the imaging modality of choice to evaluate the glenohumeral joint.


  • 8

    Indications for surgical intervention about the shoulder include infantile dislocation, persistent internal rotation contracture despite nonoperative measures, and progressive glenohumeral deformity.


  • 9

    Extraarticular procedures, including subscapularis and pectoralis lengthening in combination with tendon transfers improve global shoulder function in patients with BPP and internal rotation contractures.


  • 10

    Clinical studies support reduction of the glenohumeral joint either open or arthroscopically, if glenohumeral joint deformity is noted. For patients with advanced glenohumeral deformity, improved function may be achieved with derotational osteotomy of the humerus.





Introduction


Despite advances in prenatal and obstetrical care, the estimated prevalence of brachial plexus palsy remains between 0.1% and 0.4% of live births. The majority of children demonstrate spontaneous recovery; however, some will have persistent deficits. Children with incomplete recovery following brachial plexus palsy may have functional limitations because of muscle weakness and soft tissue contractures. Deformities vary in extent and severity, depending, in part, on the type of lesion and the degree of recovery. Persistent muscle weakness and imbalance affect both bone growth and joint development. Long standing muscle imbalance may result in progressive glenohumeral deformity.




Clinical examination


Physical examination remains the mainstay of analysis and decision making for children with brachial plexus palsy (BPP). Assessing shoulder function involves observation of spontaneous activity and stimulated activity with and without gravity assistance. Passive range of motion (ROM) of the shoulder and elbow should be assessed. Internal and external rotation is performed in both adduction and abduction (90 degrees) while stabilizing the scapula against the thorax ( Figure 10.1 ).




Figure 10.1


Stabilization of the scapula against the thorax is necessary to assess passive internal and external rotation

(courtesy of Shriners Hospital for Children, Philadelphia).


The degree of scapular winging posteriorly with internal rotation, superiorly with adduction, and into the axilla with full abduction and forward flexion is recorded. Active abduction should be documented, noting any hyperlordosis of the back and lateral trunk motion. Patients with upper trunk involvement (C5–6) have residual weakness of the deltoid and rotator cuff muscles, limiting shoulder abduction and external rotation. Subscapularis tightness is evaluated by measuring the scapular-humeral angle in abduction with the scapula stabilized. Pectoralis, latissimus dorsi, and teres tightness is assessed by palpation of the muscles in abduction and external rotation.


It is important to palpate for posterior humeral head dislocation. If the shoulder rests in a dislocated position, external rotation will be limited, but this will improve considerably with reduction of the humeral head into the glenoid. Internal rotation contractures and glenohumeral deformity have been described in children as young as 5 months of age. Infantile dislocations of the shoulder have also been reported. Moukoko et al. described posterior shoulder subluxation/dislocation in neonates and infants with BPP. Mean age at the time of diagnosis was 6 months (range, 3–10 months). Clinical signs included asymmetry of the skin folds in the axilla, apparent shortening of the humeral segment, and a palpable fullness of the shoulder posteriorly ( Figure 10.2 ). There was no correlation noted between the occurrence of subluxation/dislocation and the initial neurologic deficit. The most salient clinical finding was the loss of passive external rotation between examinations, which indicated a posterior shoulder subluxation/dislocation.








Figure 10.2


Nine-year-old with left residual BPP and frank shoulder subluxation (courtesy of Shriners Hospital for Children, Philadelphia). (A) Apparent shortening of the humeral segment; (B) lack of passive external rotation; and (C) palpable fullness of the humeral head posterior to the glenoid.


Recovery of muscle strength in children is graded by the Mallet Classification or Hospital for Sick Children scores. Fear of examination, lack of coordination, and inability to comprehend directions by the children challenge the examiner to assess active ROM and strength in the young child. The Hospital for Sick Children in Toronto, Canada developed the Active Movement Scale (AMS) as an alternative to the muscle grading system commonly used for adults. However, when contractures are present, this system is a limited tool because grades of strength may not sufficiently represent motor function.


The modified Mallet scale is commonly used to assess shoulder function. A scale of 1 to 5 is used to evaluate shoulder abduction, global external rotation, and hand to neck, hand to back, and hand to mouth positions ( Figure 10.3 ). An aggregate score is calculated by summing the 5 individual scores, with a maximum score of 25. Regarding internal rotation, we recognized that many children with residual BPP can not perform hand to spine prior to surgery (grade 1 or 2 Mallet score), but can perform midline tasks. Therefore, measurements of hand to spine may not detect loss of midline function, such as buttoning, zippering, and toileting. For this reason, we added a measure of midline function (a sixth subscale to the Mallet) to better assess loss of internal rotation and function ( Figure 10.4 ). This additional measure balances the Mallet, which is weighted toward external rotation. The standard Mallet scores 3 activities of external rotation (external rotation, hand to neck, and hand to mouth) and only one of internal rotation (hand to spine). Measuring midline function decreases the bias toward external rotation and provides an assessment of midline activity, which is important for activities of daily living. Although no perfect scale exists that can be applied to all children, these tools, used in conjunction with measures of active and passive ROM of the upper extremity, aid the physician in making treatment decisions.












Figure 10.3


Nine-year-old with left residual BPP demonstrating Mallet movements (courtesy of Shriners Hospital for Children, Philadelphia). (A) Shoulder abduction (grade IV); (B) global external rotation (grade II); (C) hand to neck (grade II); (D) hand to back (grade II).(E) hand to mouth (grade II).



Figure 10.4


Modified Mallet with sixth subscale to better assess midline function

(courtesy of Shriners Hospital for Children, Philadelphia).




Clinical examination


Physical examination remains the mainstay of analysis and decision making for children with brachial plexus palsy (BPP). Assessing shoulder function involves observation of spontaneous activity and stimulated activity with and without gravity assistance. Passive range of motion (ROM) of the shoulder and elbow should be assessed. Internal and external rotation is performed in both adduction and abduction (90 degrees) while stabilizing the scapula against the thorax ( Figure 10.1 ).




Figure 10.1


Stabilization of the scapula against the thorax is necessary to assess passive internal and external rotation

(courtesy of Shriners Hospital for Children, Philadelphia).


The degree of scapular winging posteriorly with internal rotation, superiorly with adduction, and into the axilla with full abduction and forward flexion is recorded. Active abduction should be documented, noting any hyperlordosis of the back and lateral trunk motion. Patients with upper trunk involvement (C5–6) have residual weakness of the deltoid and rotator cuff muscles, limiting shoulder abduction and external rotation. Subscapularis tightness is evaluated by measuring the scapular-humeral angle in abduction with the scapula stabilized. Pectoralis, latissimus dorsi, and teres tightness is assessed by palpation of the muscles in abduction and external rotation.


It is important to palpate for posterior humeral head dislocation. If the shoulder rests in a dislocated position, external rotation will be limited, but this will improve considerably with reduction of the humeral head into the glenoid. Internal rotation contractures and glenohumeral deformity have been described in children as young as 5 months of age. Infantile dislocations of the shoulder have also been reported. Moukoko et al. described posterior shoulder subluxation/dislocation in neonates and infants with BPP. Mean age at the time of diagnosis was 6 months (range, 3–10 months). Clinical signs included asymmetry of the skin folds in the axilla, apparent shortening of the humeral segment, and a palpable fullness of the shoulder posteriorly ( Figure 10.2 ). There was no correlation noted between the occurrence of subluxation/dislocation and the initial neurologic deficit. The most salient clinical finding was the loss of passive external rotation between examinations, which indicated a posterior shoulder subluxation/dislocation.








Figure 10.2


Nine-year-old with left residual BPP and frank shoulder subluxation (courtesy of Shriners Hospital for Children, Philadelphia). (A) Apparent shortening of the humeral segment; (B) lack of passive external rotation; and (C) palpable fullness of the humeral head posterior to the glenoid.


Recovery of muscle strength in children is graded by the Mallet Classification or Hospital for Sick Children scores. Fear of examination, lack of coordination, and inability to comprehend directions by the children challenge the examiner to assess active ROM and strength in the young child. The Hospital for Sick Children in Toronto, Canada developed the Active Movement Scale (AMS) as an alternative to the muscle grading system commonly used for adults. However, when contractures are present, this system is a limited tool because grades of strength may not sufficiently represent motor function.


The modified Mallet scale is commonly used to assess shoulder function. A scale of 1 to 5 is used to evaluate shoulder abduction, global external rotation, and hand to neck, hand to back, and hand to mouth positions ( Figure 10.3 ). An aggregate score is calculated by summing the 5 individual scores, with a maximum score of 25. Regarding internal rotation, we recognized that many children with residual BPP can not perform hand to spine prior to surgery (grade 1 or 2 Mallet score), but can perform midline tasks. Therefore, measurements of hand to spine may not detect loss of midline function, such as buttoning, zippering, and toileting. For this reason, we added a measure of midline function (a sixth subscale to the Mallet) to better assess loss of internal rotation and function ( Figure 10.4 ). This additional measure balances the Mallet, which is weighted toward external rotation. The standard Mallet scores 3 activities of external rotation (external rotation, hand to neck, and hand to mouth) and only one of internal rotation (hand to spine). Measuring midline function decreases the bias toward external rotation and provides an assessment of midline activity, which is important for activities of daily living. Although no perfect scale exists that can be applied to all children, these tools, used in conjunction with measures of active and passive ROM of the upper extremity, aid the physician in making treatment decisions.


Apr 10, 2019 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Shoulder sequelae in children with brachial plexus palsy
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