W. J. R. van Ouwerkerk

Deformities of the shoulder in infants younger than 12 months with an obstetric lesion of the brachial plexus

We performed a prospective study using MRI in 16 consecutive infants with a mean age of 5.2 months (2.7 to 8.7) who had shown inadequate recovery from an obstetric lesion of the brachial plexus in the first three months of life, in order to identify early secondary deformities of the shoulder. Shoulders were analysed according to a standardised MRI protocol. Measurements were made of the appearance of the glenoid, glenoid version and the position of the humeral head. The appearance of the glenoid on the affected side was normal in only seven shoulders. In the remainder it was convex in seven and bioconcave in three. The degree of subluxation of the humeral head was significantly greater (p = 0.01) in the affected shoulders than in normal shoulders (157 degrees v 170 degrees). The presence of an abnormal appearance of the glenoid, retroversion of the glenoid and subluxation of the humeral head increased with age. There was a statistical difference (p = 0.05) between infants younger than five months and those who were older.

Management of obstetric brachial plexus lesions: state of the art and future developments.

Abstract Despite improving perinatal care the incidence of obstetric brachial plexus lesions (OBPL) has not declined. Most babies recover spontaneously. In 10–20% recovery is incomplete. To prevent lasting functional deficits early referral to specialized centers is necessary. If the biceps shows no function at 3 months, standardized clinical assessment and additional investigations must delineate the extent of a lesion. Detection of root avulsions by myelography and computed tomography combined with electrodiagnostics remains inconclusive in 15% of cases. Plexus reconstruction is performed during the 4th–6th months. Contractures or deformities are treated conservatively or by orthopedic surgery. Long-term rehabilitation is required. In future, aspects of prevention need attention. Improving imaging and neurophysiological techniques are promising for greater precision in detecting root avulsions and even spontaneous recovering nerves. Functional imaging will allow better understanding of central integration and plasticity. New pharmacological agents may promote nerve regeneration.

Retroversion of the humeral head in children with an obstetric brachial plexus lesion.

We undertook a prospective MRI study to measure the retroversion of the humeral head in 33 consecutive infants with a mean age of 1 year 10 months (3 months to 7 years 4 months) who had an obstetric brachial plexus lesion (OBPL). According to a standardised MRI protocol both shoulders and humeral condyles were examined and the shape of the glenoid and humeral retroversion determined. The mean humeral retroversion of the affected shoulder was significantly increased compared with the normal contralateral side (-28.4 +/- 12.5 degrees v -21.5 +/- 15.1 degrees, p = 0.02). This increase was found only in the children over the age of 12 months. In this group humeral retroversion was -29.9 +/- 12.9 degrees compared with -19.6 +/- 15.6 degrees in the normal shoulder (p = 0.009), giving a mean difference of 10.3 degrees (95% confidence interval 3.3 to 17.3). This finding is of importance when considering the operative treatment for subluxation of the shoulder in children with an OBPL.

Cerebellar dermoid tumor and occipital meningocele in a monozygotic twin: clues to the embryogenesis of craniospinal dysraphism

A case of monochorionic/monoamnionic twin with discordant occipital developmental malformations is presented. One female twin appeared to have an occipital meningocele with cerebellar aplasia and died immediately after birth. The other twin presented with signs and symptoms of raised intracranial pressure at the age of 7 months. Severe hydrocephalus was present due to an infected intracerebellar dermoid tumor with a contiguous occipital dermal sinus. The clinical and pathological characteristics are described and the different theories concerning twinning, embryogenesis, and dysmorphology in relation to neural tube defects are discussed. Analysis of the features of these monozygotic twins indicates that a meningocele is not a post-neurulation disorder but results from deficient neurulation, probably due to mesodermal insufficiency.

Features of proliferation and in vitro drug resistance in central primitive neuro-ectodermal tumours.

The features of proliferation in brain tumours are related with clinical prognosis for several types of brain tumours, especially gliomas. For childhood central primitive neuro‐ectodermal tumours (cPNET), including medulloblastoma, this relation has previously been unclear. The aim of this study is to investigate the relationship between proliferative features of cPNET and in vitro resistance for cytostatic drugs measured with the 3‐4,5‐dimethylthiazol‐2‐yl‐2,5‐diphenyltetrazolium‐bromide (MTT) assay. Tumour material was obtained from 23 surgical specimens of cPNET. The expression of the proliferation markers Ki‐67, proliferating cell nuclear antigen (PCNA) and cyclin D1 was determined with immunohistochemistry, while S‐phase and DNA ploidy were analysed by flowcytometric analysis cell scan (FACS). The in vitro resistance for 10 cytostatic drugs was determined with the MTT assay. Drug resistance levels were available in 19 (83%) of the 23 samples with a complete profile of 10 cytostatic drugs tested in 14 samples. An excellent correlation in drug resistance scores was found between pharmacologically related drugs. The Ki‐67 staining in 20 samples varied from 10 to 60% and from 30 to 100% for PCNA. Cyclin D1 staining was negative in 11 out of 18 samples. The S‐phase in 16 samples ranged from 2 to 16%. Increased staining of Ki‐67 was related with actinomycin D sensitivity (r −.603; P=0.022), while cells with a higher S‐phase percentage were more resistant to ifosfamide (r .952; P<0.0001). In vitro drug resistance testing of central primitive neuro‐ectodermal tumours (PNET) is feasible with the MTT assay. Ifosfamide resistance was related with increased Ki‐67 and S‐phase percentage of the tumour cells, while increased Ki‐67 was also related with actinomycin D sensitivity. These findings suggest a cell cycle dependent activity of cytostatic drugs in vitro.

Musculoskeletal growth in the upper arm in infants after obstetric brachial plexus lesions partial denervation and its relation with residual muscle function

Aim  Denervation after obstetric brachial plexus lesion (OBPL) is associated with reduced musculoskeletal growth in the upper arm. The aim of this study was to investigate whether reduced growth of upper arm flexor and extensor muscles is related to active elbow function and humeral length.