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The fabrication of periodic dot structures by laser-induced surface electromagnetic wave (SEW) etching of n-GaAs substrates is discussed. A frequency-tripled Nd:YAG laser incorporated in a holographic exposure system is used to perform the etching of holographic grooves on GaAs samples. The resulting dot structures are then examined with scanning electron microscopy and atomic force microscopy. The microscopic measurements show that laser-induced SEW etching is very useful for the fabrication of small dot structures with unique physical properties.

Background: Botulinum toxin A is used to treat contractures in children with spasticity by temporarily interfering with neural transmission at the motor end plate. In infants with brachial plexus palsy, posterior shoulder subluxation and dislocation are the result of muscle imbalance, in which neurologic recovery is evolving, and spasticity is not a deforming force. We postulated that temporary weakening of the shoulder internal rotator muscles with botulinum toxin A would facilitate reduction of the glenohumeral joint in such infants with early posterior shoulder subluxation or dislocation.Methods: Thirty-five infants with posterior subluxation or dislocation of the shoulder due to brachial plexus palsy were treated with botulinum toxin A between January 1999 and December 2006, and were followed for a minimum period of one year. Records were reviewed for the severity of the palsy, age at time of treatment, recurrence of subluxation or dislocation, and the subsequent need for further treatment to reduce the glenohumeral joint.Results: The average age at the time of shoulder reduction and botulinum toxin-A injection was 5.7 months. Six patients had a second injection. Reduction of the shoulder was maintained in twenty-four (69%) of the thirty-five patients. There were no complications related to the use of botulinum toxin A.Conclusions: Although there may be specific risks associated with its use, botulinum toxin-A injection into the internal rotator muscles is a useful adjunct to the treatment of early posterior subluxation or dislocation of the shoulder in infants with neonatal brachial plexus palsy, and may help to avoid the need for open surgical procedures to restore or maintain shoulder reduction. [ABSTRACT FROM AUTHOR]

Background: Ultrasonographic evaluation of the hip in infants is considered both reliable and reproducible in the diagnosis of developmental dysplasia of the hip. Ultrasonographic evaluation of the shoulder in infants has been reported as a valuable diagnostic aid in dysplastic development following neonatal brachial plexus palsy. To our knowledge, there has been no study of the intraobserver reproducibility and interobserver reliability of sonography of the shoulder in infants with and without suspected posterior shoulder dislocation.Methods: Two identical but randomly ordered sets of the same deidentified sonographic images of shoulders in infants were given to radiologists, pediatric orthopaedists and orthopaedic residents, and fellows with varying degrees of experience in the evaluation of shoulder pathology in infants, who measured the position of the humeral head relative to the axis of the scapula. Intraobserver reproducibility and interobserver reliability of the measurements were assessed.Results: For the position of the humeral head with respect to the glenoid in both normal and abnormal conditions, the Pearson correlation coefficient for intraobserver reproducibility was 0.91 and the intraclass correlation coefficient for interobserver reliability was 0.875. For estimating the percentage of the humeral head posterior to the axis of the scapula, the Pearson correlation was 0.85 and the intraclass correlation coefficient was 0.77.Conclusions: Ultrasonographic examination of the shoulder in infants to assess for the position of the humeral head with respect to the scapula showed high intraobserver reproducibility and interobserver reliability. It is recommended as a reliable technique for evaluating shoulder position in infants with neonatal brachial plexus palsy. [ABSTRACT FROM AUTHOR]

Background: In contrast to longitudinal deficiencies, phocomelia is considered a transverse, intercalated segmental dysplasia. Most patients demonstrate severe, but not otherwise classifiable, upper-extremity deformities, which usually cannot be placed into one of three previously described phocomelia groups. Additionally, these phocomelic extremities do not demonstrate true segmental deficits; the limb is also abnormal proximal and distal to the segmental defect. The purpose of this investigation was to present evidence that upper-extremity abnormalities in patients previously diagnosed as having phocomelia in fact represent a proximal continuum of radial or ulnar longitudinal dysplasia.Methods: The charts and radiographs of forty-one patients (sixty extremities) diagnosed as having upper-extremity phocomelia were reviewed retrospectively. On the basis of the findings on the radiographs, the disorders were categorized into three groups: (1) proximal radial longitudinal dysplasia, which was characterized by an absent proximal part of the humerus, a nearly normal distal part of the humerus, a completely absent radius, and a radial-sided hand dysplasia; (2) proximal ulnar longitudinal dysplasia, characterized by a short one-bone upper extremity that bifurcated distally and by severe hand abnormalities compatible with ulnar dysplasia; and (3) severe combined dysplasia, with type A characterized by an absence of the forearm segment (i.e., the radius and ulna) and type B characterized by absence of the arm and forearm (i.e., the hand attached to the thorax).Results: Twenty-nine limbs in sixteen patients could be classified as having proximal radial longitudinal dysplasia. Systemic medical conditions such as thrombocytopenia-absent radius syndrome were common in those patients, but additional musculoskeletal conditions were rare. Twenty limbs in seventeen patients could be classified as having proximal ulnar longitudinal dysplasia. Associated musculoskeletal abnormalities, such as proximal femoral focal deficiency, were common in those patients. Eleven limbs in ten patients were identified as having severe combined dysplasia, which was type A in seven of them and type B in four. Four patients with severe combined dysplasia had congenital cardiac anomalies, and four had associated musculoskeletal abnormalities. Three of the four patients with the type-B disorder had a contralateral ulnar longitudinal dysplasia.Conclusions: We propose that cases previously classified as upper-extremity phocomelia represent a spectrum of severe longitudinal dysplasia, as none of the sixty extremities that we studied demonstrated a true intercalary deficiency. These findings have both developmental and genetic implications. [ABSTRACT FROM AUTHOR]

Background: An important prognostic factor in neonatal brachial plexus palsy is the time interval to biceps muscle recovery. Although the natural history is not clear, biceps muscle recovery after more than three months of age has been used to predict poor long-term shoulder function. The absence of biceps muscle function at three months of age has been adopted as an indication for early brachial plexus microsurgery, in an attempt to improve recovery. To provide a benchmark for outcome comparison, the long-term outcome of patients with absent biceps muscle function at three months of age was studied.Methods: Between 1980 and 1992, 170 patients with neonatal brachial plexus palsy were entered into a prospective study in which details of the birth and serial clinical examinations were recorded. Patients were grouped according to the level of injury and the time interval to biceps muscle recovery. Twenty-nine patients were observed to have absent biceps muscle function at three months of age. Twenty-eight of those patients were available for long-term followup at a mean age of eleven years and one month. At the time of follow-up, patients answered a questionnaire and underwent manual muscle strength testing, sensory evaluation, and grading of their shoulder function according to Gilbert's modification of the Mallet score, in which the function was graded as II, III, or IV with class I (no function) and V (normal) eliminated. The level of injury and the time that biceps muscle function returned were compared with the final outcomes.Results: The level of injury was C5-C6 in thirteen (46%) of our twenty-eight patients with absent biceps muscle function at three months of age, C5-C7 in five (18%), and pan-plexus (C5-T1) in ten (36%). Biceps contraction was observed by six months of age in twenty patients (71%), including all thirteen patients with a C5-C6 level of injury. Twenty-two patients did not have surgery on the brachial plexus, but nine of those patients had subsequent orthopaedic procedures. At the time of follow-up, twenty-seven of the twenty-eight patients had at least antigravity biceps muscle function. Patients who regained biceps muscle function between three and six months of age had better scores for abduction (p = 0.04) and for hand-to-neck (p = 0.05) and hand-to-back (p < 0.001) function than did patients who regained biceps muscle function after six months of age. Patients with a C5-C6 lesion had better scores for external rotation (p = 0.04) and for hand-to-neck (p = 0.05), hand-to-mouth (p < 0.01), and hand-to-back (p < 0.001) function than did patients with a pan-plexus lesion. Twelve (55%) of the twenty-two patients who did not have brachial plexus surgery had a class-IV shoulder (good function) according to the modified Mallet score. Of the twelve patients with a C5-C6 level of injury who did not have brachial plexus surgery, eight had a class-IV shoulder.Conclusions: This study indicated associations between prolonged neurological recovery and a more extensive level of injury and worse long-term shoulder function. Patients with a C5-C6 injury and absent biceps muscle function at three months of age often have good long-term shoulder function without brachial plexus surgery. [ABSTRACT FROM AUTHOR]

Background: Glenoid dysplasia and posterior shoulder subluxation with resultant shoulder stiffness is a well-recognized complication in infants with neonatal brachial plexus palsy. It is generally considered to be the result of a slowly progressive glenohumeral deformation secondary to muscle imbalance, physeal trauma, or both. Recent publications about infantile posterior shoulder dislocation have suggested that the onset of dysplasia occurs at an earlier age than has been previously recognized. The prevalence of early dislocation in infants with this disorder has not been previously reported, to our knowledge.Methods: We studied 134 consecutive infants with neonatal brachial plexus palsy who were seen at our institution over a period of two years. All infants were examined at monthly intervals to assess neurological recovery and the status of the upper extremity until recovery occurred or a treatment plan was established. The type of brachial plexus involvement was classified. Specific clinical signs associated with subluxation and dislocation were recorded. These included asymmetry of skin folds of the axilla or the proximal aspect of the arm, apparent shortening of the humeral segment, a palpable asymmetric fullness in the posterior region of the shoulder, or a palpable click during shoulder manipulation. The infants who were identified as having these clinical signs were evaluated with ultrasonographic imaging studies.Results: Eleven (8%) of the 134 infants had a posterior shoulder dislocation. The mean age at the time of diagnosis was six months (range, three to ten months). There was no correlation between the occurrence of dislocation and the type of initial neurological deficit. A rapid loss of passive external rotation between monthly examinations indicated a posterior shoulder dislocation.Conclusions: Posterior shoulder dislocation can occur earlier (before the age of one year) and more rapidly in infants with neonatal brachial plexus palsy than has been appreciated previously. As with developmental dysplasia of the hip, a high index of suspicion, recognition of clinical signs, and the use of ultrasonography will allow the diagnosis to be established. Following early diagnosis, attention should be focused on improving the stability and congruency of the shoulder joint. [ABSTRACT FROM AUTHOR]