Brachial plexus birth injury: US screening for glenohumeral joint instability.

PURPOSE: To prospectively evaluate the use and optimal timing of ultrasonographic (US) screening for posterior shoulder subluxation in infantswith brachial plexus birth injury (BPBI). MATERIALS AND METHODS: Approval of the ethics committee and informed consent of guardians was obtained. This population-based prospective study included neonates with BPBI who were born in Helsinki from January 1, 2003 through December 31, 2006, and in whom BPBI was verified with sequential clinical examinations. US was performed at 1, 3, 6, and 12 months. Size (width and height) of the humeral head and its ossification center and congruency of the shoulder (alpha angle) were measured. Frequency of BPBI and permanent changes were evaluated. This study also included patients who were referred from the tertiary catchment area. For statistical analysis, 95% confidence intervals were calculated, and analysis of variance was performed. RESULTS: BPBI was seen in 132 of 41980 neonates (3.1 per 1000). In 27 cases (0.64 per 1000), BPBI did not heal during the 1st year of life and was considered permanent. The humeral head and its ossification center were smaller on the affected side in permanent BPBI. Nine patients with permanent palsy had posterior subluxation of the humeral head depicted with US (alpha angle, >30 degrees ). In five patients, posterior subluxation [corrected] was detected at 3 months. Nineteen of 21 patients with BPBI from the tertiary catchment area had permanent palsy. Ten of 19 patients developed posterior subluxation of the shoulder, which was verified with US. Altogether, three of these cases were not detected by surgeons. Posterior subluxation of the humeral head developed during the 1st year of life in one-third of patients with permanent BPBI. In more than one-half (55% [five of nine]) of the patients, posterior subluxation [corrected] was detected with US at 3 months, and in 89% (eight of nine), it was detected at 6 months. CONCLUSION: US is a fast and useful tool for diagnosis of posterior subluxation of the humeral head, and examination of the glenohumeral joint should be performed at 3 and 6 months of age in infants with BPBI if symptoms persist.

A novel mutation of the GAA gene in a Finnish late-onset Pompe disease patient: clinical phenotype and follow-up with enzyme replacement therapy.

Pompe disease is a rare, progressive disease leading to skeletal muscle weakness due to deficiency of the acid alpha-glucosidase (GAA) enzyme. Herein we report the first diagnosed Finnish patient with a phenotype compatible with the late-onset form of Pompe disease. Molecular genetic analysis of the GAA gene revealed a novel missense mutation, 1725C>A (Y575X), combined with a previously reported mutation, 1634C>T (P545L). Human recombinant alpha-glucosidase enzyme (alglucosidase-alpha) treatment was initiated for this patient at age 20 years. After 12 months she was no longer fully wheelchair-bound, and muscle strength had improved. No disease progression was visible on muscle magnetic resonance imaging of the lower limbs, and the energy state of the muscle cells increased by 46% on phosphorus magnetic resonance spectroscopy. Overall, our findings suggest that enzyme replacement therapy is indicated, even in patients with late-onset Pompe disease, to halt disease progression and improve the quality of daily life.

Muscle changes in brachial plexus birth injury with elbow flexion contracture: an MRI study.

BACKGROUND: Muscle pathology of the arm and forearm in brachial plexus birth injury (BPBI) with elbow flexion contracture has not been evaluated with MRI. OBJECTIVE: To determine whether limited range of motion of the elbow in BPBI is correlated with specific patterns of muscular pathology. MATERIALS AND METHODS: For 15 BPBI patients, total active motion (TAM) of the elbow (extension-flexion) and the forearm (pronation-supination) were measured. MRI of the elbow joints and musculature allowed assessment of elbow congruency. Fatty infiltration and size reduction of the muscles were graded semiquantitatively. RESULTS: Mean TAM of the elbow was 113 degrees (50 degrees-140 degrees) and that of the forearm 91 degrees (10 degrees-165 degrees). The greater the size reduction of the brachioradialis muscle, the more diminished was elbow TAM. The more extensive the BPBI and muscle pathology of the pronator teres muscle, the more limited was the TAM of the forearm. Pathology of the supinator and brachialis muscles was evident in every patient. CONCLUSION: Extensive BPBI may result in marked limitation of TAM. Elbow flexion contracture seems to be caused mainly by brachialis muscle pathology. Prosupination of the forearm is better preserved when the pronator teres is not severely affected. MRI can reliably show the extent of muscle pathology in BPBI.

MRI of rotator cuff muscle atrophy in relation to glenohumeral joint incongruence in brachial plexus birth injury.

PURPOSE: To evaluate rotator cuff muscles and the glenohumeral (GH) joint in brachial plexus birth injury (BPBI) using MRI and to determine whether any correlation exists between muscular abnormality and the development of glenoid dysplasia and GH joint incongruity. MATERIALS AND METHODS: Thirty-nine consecutive BPBI patients with internal rotation contracture or absent active external rotation of the shoulder joint were examined clinically and imaged with MRI. In the physical examination, passive external rotation was measured to evaluate internal rotation contracture. Both shoulders were imaged and the glenoscapular angle, percentage of humeral head anterior to the middle of the glenoid fossa (PHHA) and the greatest thickness of the subscapular, infraspinous and supraspinous muscles were measured. The muscle ratio between the affected side and the normal side was calculated to exclude age variation in the assessment of muscle atrophy. RESULTS: All muscles of the rotator cuff were atrophic, with the subscapular and infraspinous muscles being most severely affected. A correlation was found between the percentage of humeral head anterior to the middle of the glenoid fossa (PHHA) and the extent of subscapular muscle atrophy (r(s)=0.45, P=0.01), as well as between its ratio (r(s)=0.5, P P=0.01). Severity of rotator cuff muscle atrophy correlated with increased glenoid retroversion and the degree of internal rotation contracture. CONCLUSIONS: Glenoid retroversion and subluxation of the humeral head are common in patients with BPBI. All rotator cuff muscles are atrophic, especially the subscapular muscle. Muscle atrophy due to neurogenic damage apparently results in an imbalance of the shoulder muscles and progressive retroversion and subluxation of the GH joint, which in turn lead to internal rotation contracture and deformation of the joint.