Radiology: Ultrasound useful in assessing birth injuries in infants

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Ultrasonographic screening (US) is both a quick and useful tool in the diagnosis of posterior subluxation of the humeral head, examination of the glenohumeral joint and should be employed at three and six months of age in infants with brachial plexus birth injury (BPBI) if symptoms persist, according to a study published in the January edition of Radiology.

Tiina H. Pöyhiä, MD, of the Helsinki Medical Imaging Center in Finland, and colleagues utilized US in the prospective study of 132 newborns that had been previously diagnosed with BPBI at Women’s Hospital in Helsinki, Finland. The study included 73 girls and 59 boys, 73 of whom presented with affected right side and 59 with left side affected.

During the time period of the study (Jan. 1, 2003 to Dec. 31, 2006), approximately 3.1 per 1,000 infants born in this patient-population presented with BPBI, and were referred to Hospital for Children and Adolescents in Helsinki.

Delivery mode, added assistance during delivery, and birth weight of the patients were recorded by the authors. The researchers' inclusion criteria in recruiting patients for this study were noted as any newborn suspected of having BPBI after a routine examination at two days of age, conducted by a pediatrician and physiotherapist specializing in BPBI.

At one, three, six and 12 months post-birth, US was performed on both shoulders of the infants in order to screen for posterior shoulder subluxation. Size (width and height) of the humeral head and its ossification center and congruency of the shoulder were measured. Also evaluated by the researchers was frequency of BPBI and permanent changes.

The researchers utilized a US technique which included both a static evaluation of joint congruency in maximal internal and external rotation, by using a posterior axial approach with the upper arm of the patient and the elbow flexed to 90 degrees and a dynamic evaluation of glenohumeral instability. The shoulders of the infants were scanned during the full range of internal to external rotation.

Newborns were excluded from the study if at follow-up, full clinical recovery was noted. Of the 132 patients with BPBI from Women’s Hospital, 50 had a full recovery before the one-month mark post-birth, 43 had a full recovery before three months and one patient had a full recovery before 12 months of age.

Of the 132 reviewed cases, 27 BPBI cases could be classified as permanent as they did not heal during the first year of life.  Of the 27 permanent cases, posterior subluxation was detected by ultrasound in 55 percent of patients at three months of age and in 89 percent of patients at six months of age, wrote the authors.

No other imaging modality was used to verify the US findings, as MRI would have required anesthesia or sedation of the patients, noted the authors.

“The risk for shoulder instability in permanent BPBI is high during the first year of life,” said Pöyhiä and collegues, concluding that routine US of the glenohumeral joint at the ages of three and six months in infants with BPBI is an effective diagnosis tool.