Imaging assessment of glenohumeral dysplasia secondary to brachial plexus birth palsy

Team Approach: Management of Brachial Plexus Birth Injury

Brachial plexus birth injury is an upper-extremity paralysis that occurs from a traction injury to the brachial plexus during birth. Approximately 10% to 30% of children with a brachial plexus birth injury have residual neurologic deficits with associated impact on upper-limb function. Management of brachial plexus birth injuries with a multidisciplinary team allows optimization of functional recovery while avoiding unnecessary intervention. Early occupational therapy should be initiated with a focus on range of motion and motor learning. The need for microsurgical reconstruction of the brachial plexus can be predicted based on early physical examination findings, and reconstruction is generally performed at 3 to 9 months of age. The majority of children with residual neurologic deficits develop associated glenohumeral dysplasia. These children may require secondary procedures, including botulinum toxin injection, subscapularis and pectoralis lengthening, shoulder capsular release, shoulder tendon transfer, and humeral osteotomy.

Anatomical study of the brachial plexus in human fetuses and its relation with neonatal upper limb paralysis

Objective

To study the anatomy of the brachial plexus in fetuses and to evaluate differences in morphology during evolution, or to find anatomical situations that can be identified as the cause of obstetric paralysis.

Methods

Nine fetuses (12 to 30 weeks of gestation) stored in formalin were used. The supraclavicular and infraclavicular parts of the brachial plexus were dissected.

Results

In its early course, the brachial plexus had a cord-like shape when it passed through the scalene hiatus. Origin of the phrenic nerve in the brachial plexus was observed in only one fetus. In the deep infraclavicular and retropectoralis minor spaces, the nerve fibers of the brachial plexus were distributed in the axilla and medial bicipital groove, where they formed the nerve endings.

Conclusion

The brachial plexus of human fetuses presents variations and relations with anatomical structures that must be considered during clinical and surgical procedures for neonatal paralysis of the upper limbs.

The Pathogenesis of Glenohumeral Deformity and Contracture Formation in Obstetric Brachial Plexus Palsy-A Review

Contractures of the shoulder joint and glenohumeral joint dysplasia are well known complications to obstetrical brachial plexus palsy. Despite extensive description of these sequelae, the exact pathogenesis remains unknown. The prevailing theory to explain the contractures and glenohumeral joint dysplasia states that upper trunk injury leads to nonuniform muscle recovery and thus imbalance between internal and external rotators of the shoulder. More recently, another explanation has been proposed, hypothesizing that denervation leads to reduced growth of developing muscles and that reinnervation might suppress contracture formation. An understanding of the pathogenesis is desirable for development of effective prophylactic treatment. This article aims to describe the current state of knowledge regarding these important complications.

Modified Friedman technique: a new proposed method of measuring glenoid version in the setting of glenohumeral dysplasia

BACKGROUND

Glenoid version angles are measured to objectively follow changes related to glenohumeral dysplasia in the setting of brachial plexus birth palsy. Measuring glenoid version on cross-sectional imaging was initially described by Friedman et al. in 1992. Recent literature for non-dysplastic shoulders advocates time-consuming reconstructions and reformations for an accurate assessment of glenoid version.

OBJECTIVE

To compare Friedman's original method for measuring glenoid version to a novel technique we developed ("modified Friedman") with the reference standard of true axial reformations.

MATERIALS AND METHODS

With institutional review board approval, we retrospectively examined 30 normal and dysplastic shoulders obtained from magnetic resonance imaging examinations of 30 patients with an established diagnosis of brachial plexus birth palsy between January 2012 and September 2017. Four pediatric radiologists performed glenoid version measurements using Friedman's method, the modified Friedman method and a previously described true axial reformation method. The modified Friedman technique better accounts for scapular positioning by selecting a reference point related to the acromion-scapular body interface. Inter-rater reliability and inter-method agreement were assessed using intraclass correlation, paired t-tests and mixed linear model analysis. Equivalence tests between methods were performed per reader.

RESULTS

Glenoid version measurements were significantly different when comparing Friedman's method to true axial reformations in normal (-10.8±5.7° [mean±standard deviation] vs. -8.8±5.3°; P≤0.001) and dysplastic shoulders (-34.6±17.7° vs. -28.1±17.5°; P≤0.001). Glenoid version measurements were not significantly different when comparing the modified Friedman's method to true axial reformations in normal (-6.3±5.8° vs. -8.8±5.3°; P=0.06) and dysplastic shoulders (-29.0±18.3° vs. -28.1±17.5°; P=0.06). Friedman's method was not equivalent to true axial reformations for measurements in dysplastic shoulders for all readers (P=0.68, 0.81, 0.86, 0.99); the modified Friedman method was equivalent to of true axial reformations for measurements in dysplastic shoulders for 3 of 4 readers (P≤0.001, P≤0.001, P≤0.001, P=0.10).

CONCLUSION

In glenohumeral dysplasia, the modified Friedman method and post-processed true axial reformations provide statistically similar and reproducible values. We propose that our modified Friedman technique can be performed in lieu of post-processed true axial reformations to generate glenoid version measurements.

Adding Value to the Magnetic Resonance Examination in a Case of Brachial Plexus Birth Palsy

We report a case of brachial plexus birth palsy in an infant with the inability to move the left upper limb since birth. There was neither history of birth trauma nor any complications during delivery. Magnetic resonance imaging (MRI) of brachial plexus showed postganglionic injury with musculoskeletal abnormalities. The child underwent surgical repair of the plexus and is on physical rehabilitation. In this case report, we discuss the utility of a single MRI examination with an elaborate discussion on various MRI signs of brachial plexus injury including secondary musculoskeletal manifestations. The case reiterates the significance of two-in-one approach while imaging these cases with MRI. Apart from reporting the damage to the brachial plexus, the radiologist should actively search for glenohumeral dysplasia. Awareness of classification and assessment of glenohumeral dysplasia should be routinely included as an integral part of imaging report as it adds incremental value to the overall patient management and functional outcome.

The usefulness of chemical-shift magnetic resonance imaging for the evaluation of osteoid osteoma

Objective

The purpose of this study was to determine whether chemical-shift magnetic resonance imaging (MRI) could be useful in the diagnosis of osteoid osteoma when clinical and radiological tumor features are inconclusive.

Materials and Methods

This retrospective study included 17 patients who underwent chemical-shift MRI for the evaluation of osteoid osteoma. For all patients, two musculoskeletal radiologists independently recorded signal intensities on in-phase and out-of-phase images in the nidus of the tumor, in abnormal-intensity bone marrow surrounding the lesion, and in normal-appearing bone marrow. For each region, relative signal intensity ratios were calculated by dividing out-of-phase by in-phase values. Relative ratios > 1 were considered indicative of neoplastic lesions. Statistical analysis was carried out to analyze the sample. Inter-observer and intra-observer agreement for each imaging method were assessed using intraclass correlation coefficients according to the Fleiss method and a value > 0.65 was considered to indicate substantial agreement.

Results

The mean relative signal intensity ratios were 1.2 (range, 0.9-1.4) for the nidus and 0.35 (range, 0.11-0.66) for the surrounding tissue; these values differed significantly from the relative signal-intensity ratios for normal-appearing bone marrow (p < 0.05).

Conclusion

Chemical-shift MRI is useful for the diagnosis and evaluation of osteoid osteoma.

Mechanical birth-related trauma to the neonate: An imaging perspective

Mechanical birth-related injuries to the neonate are declining in incidence with advances in prenatal diagnosis and care. These injuries, however, continue to represent an important source of morbidity and mortality in the affected patient population. In the United States, these injuries are estimated to occur among 2.6% of births. Although more usual in context of existing feto-maternal risk factors, their occurrence can be unpredictable. While often superficial and temporary, functional and cosmetic sequelae, disability or even death can result as a consequence of birth-related injuries. The Agency for Healthcare research and quality (AHRQ) in the USA has developed, through expert consensus, patient safety indicators which include seven types of birth-related injuries including subdural and intracerebral hemorrhage, epicranial subaponeurotic hemorrhage, skeletal injuries, injuries to spine and spinal cord, peripheral and cranial nerve injuries and other types of specified and non-specified birth trauma. Understandably, birth-related injuries are a source of great concern for the parents and clinician. Many of these injuries have imaging manifestations. This article seeks to familiarize the reader with the clinical spectrum, significance and multimodality imaging appearances of neonatal multi-organ birth-related trauma and its sequelae, where applicable.

Teaching points

• Mechanical trauma related to birth usually occurs with pre-existing feto-maternal risk factors.

• Several organ systems can be affected; neurologic, musculoskeletal or visceral injuries can occur.

• Injuries can be mild and transient or disabling, even life-threatening.

• Imaging plays an important role in injury identification and triage of affected neonates.

Ischiofemoral impingement secondary to valgus intertrochanteric osteotomy: a case report

We report an unusual case of ischiofemoral impingement secondary to valgus intertrochanteric osteotomy. The osteotomy was performed for treatment of epiphysiolysis of the left femoral head.