Lisa H. Lowe

Effect of Intrauterine Myelomeningocele Repair on Central Nervous System Structure and Function

Background: It has been postulated that intrauterine myelomeningocele repair might improve neurologic outcome in patients with myelomeningocele. A total of 59 such procedures have been performed at Vanderbilt University. Preliminary results suggested that the degree of hindbrain herniation is reduced by intrauterine repair. In an attempt to further quantify the possible benefits of this surgery, a subset of these patients was brought back to Vanderbilt for study. Methods: A group of 26 patients who had undergone intrauterine myelomeningocele repair underwent an extensive evaluation which included manual muscle testing, MR imaging and precise determination of the anatomic level of their lesions as well as multiple other tests. The results of this analysis were compared to those in 2 groups of historical controls. Results: In this group of patients intrauterine myelomeningocele repair substantially reduced the incidence of moderate to severe hindbrain herniation (4 vs. 50%). The incidence of shunt-dependent hydrocephalus was more modestly reduced (58 vs. 92%). The average level of leg function closely matched the average anatomic level of the lesion in both the fetal surgery and control groups. Conclusion: The most dramatic effect of intrauterine repair appears to be on hindbrain herniation. A less dramatic, but significant, reduction in shunt-dependent hydrocephalus is also seen. Prospective patients should be cautioned not to expect improvement in leg function as the result of this surgery. The potential benefits of surgery must be carefully weighed against the potential risks of prematurity.

Intrauterine Myelomeningocele Repair Reverses Preexisting Hindbrain Herniation

Background: It has been reported that intrauterine myelomeningocele repair reduces the amount of hindbrain herniation normally seen in association with the Chiari type II malformation. It is not yet known, however, whether hindbrain herniation is prevented, or whether preexisting herniation is reversed. The following study was designed to elucidate this issue. Methods: A series of 9 patients underwent intraoperative ultrasound examinations immediately prior to intrauterine myelomeningocele repair. These same patients were then evaluated postnatally using ultrasound and/or MRI. The degree of hindbrain herniation before and after repair was compared using a grading system devised by the authors. Results: Eight patients had clear evidence of moderate to severe hindbrain herniation on intraoperative scans while one was mild. In contrast, on postnatal studies 5 of 9 patients had no evidence of hindbrain herniation, while the other 4 had only mild herniation. Conclusion: Intrauterine myelomeningocele repair appears to reverse preexisting hindbrain herniation. It is postulated that continuous flow of cerebrospinal fluid through the neural placode is the force responsible for inducing migration of the cerebellum and brain stem downward through the foramen magnum. By interrupting that flow during gestation, intrauterine myelomeningocele repair enables the cerebellum and brain stem to resume a normal, or nearly normal, configuration.

Sonography of the neonatal spine: part 2, Spinal disorders.

OBJECTIVE The objective of part 2 of this article is to focus on key imaging features of common skin-covered spinal anomalies (spina bifida occulta) and to distinguish them from normal variants (previously discussed in part 1). CONCLUSION Modern imaging technology allows accurate neonatal spinal sonographic screening and the characterization of spinal abnormalities within the first few days of life. It is useful to determine the type of lesion present and to guide the type and timing of therapy.

State-of-the-Art Cranial Sonography: Part 1, Modern Techniques and Image Interpretation

OBJECTIVE In this era of radiation awareness, high-quality ultrasound is more important than ever. Although cranial sonography equipment has advanced greatly, application of modern techniques has not been utilized in a fashion commensurate to other cross-sectional modalities. This article will describe modern cranial sonography techniques, including the utility of linear imaging, use of additional fontanels, and screening Doppler imaging. CONCLUSION When modern protocols are used, cranial sonography is highly accurate for the detection of cranial abnormalities.

Sonography of the Neonatal Spine: Part 1, Normal Anatomy, Imaging Pitfalls, and Variations That May Simulate Disorders

OBJECTIVE Our objective is to discuss neonatal spine sonography with emphasis on imaging pitfalls and normal variants that may simulate disease and to distinguish them from true spinal disorders. CONCLUSION Sonography of the neonatal spine is now accepted as a highly sensitive, readily available screening study that can be used to evaluate various anomalies of the lumbar spine in most infants younger than 4 months.

Current Classification and Terminology of Pediatric Vascular Anomalies

OBJECTIVE The purpose of this article is to review new terminology to diagnose, classify, and refer patients with vascular anomalies for additional imaging, intervention, and treatment. CONCLUSION In recent decades, much has been learned regarding the histopathology, cause, and treatment of vascular anomalies. As information has been gleaned, a new classification system has emerged that divides vascular anomalies into neoplasms and malformations. Its utility is based on accurate initial diagnosis that correlates consistently with clinical presentation, disease course, and treatment.

Appendicitis and alternate diagnoses in children: findings on unenhanced limited helical CT.

Abstract The objective of this manuscript is to review and illustrate the findings of appendicitis, and of alternate diagnoses that may clinically or radiographically simulate appendicitis, on unenhanced limited CT in children. Potential pitfalls in unenhanced limited CT interpretation of pediatric patients will also be discussed.

Pyloric ratio: efficacy in the diagnosis of hypertrophic pyloric stenosis.

We sought to define a weight independent, highly sensitive and specific measurement to diagnose hypertrophic pyloric stenosis. A retrospective review of 87 children was performed. We determined the pyloric ratio (wall thickness/pyloric diameter) and its relationship to weight and compared it to standard criteria. The average pyloric ratios in normal children and in those with hypertrophic pyloric stenosis were 0.205 and 0.325, respectively (P < 0.001). A pyloric ratio of 0.27 yielded a sensitivity and specificity of 96% and 94%, respectively. The pyloric ratio maintained a linear relationship to weight in normal patients and those with hypertrophic pyloric stenosis. We conclude the pyloric ratio can be a highly sensitive, specific, and weight independent indicator of hypertrophic pyloric stenosis.

State-of-the-art cranial sonography: Part 2, pitfalls and variants.

OBJECTIVE In the first part of this article, modern cranial sonography techniques and interpretation were discussed, emphasizing ways in which the application of modern imaging technology and techniques are able to enhance detection of pathologic abnormalities on cranial sonography. CONCLUSION In this part of the article, we will describe pitfalls and variants that may be confused with pathologic abnormalities. Emphasis will be placed on recognizing normal variations and distinguishing them from pathologic abnormalities that may require additional imaging or clinical follow-up.

Radiographic Findings in the Diagnosis of Pediatric Ileocolic Intussusception Comparison to a Control Population

Several previous studies have evaluated the usefulness of plain abdominal radiographs for the diagnosis of pediatric intussusception, although investigation of the most specific clues to diagnose intussusception has not been studied alone. The 3 most specific findings of intussusception include intraluminal mass or intussusceptum, nonvisualized air-filled cecum, and obscured liver margin or right upper-quadrant mass. In this study, a retrospective review of 73 known cases of intussusception with age- and sex-matched controls was performed. The cases were reviewed by 2 blinded, board-certified pediatric radiologists to aid in the determination of sensitivity and specificity. The sensitivity and specificity of plain radiographs to correctly diagnose ileocolic intussusception in pediatric patients compared with a control population were 77% and 97%, using a 50% or greater receiver operating characteristic curve cutoff.