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Biomedical subjects

R Towbin

Publications and source records attributed to R Towbin.

At least 19 recordsLinked to original sources
PubMed2001

Pediatric tracheotomy: is postoperative chest X-ray necessary?

A retrospective study of 101 children who underwent tracheotomy at the Children's Hospital of Pittsburgh from 1993 to 1996 was performed. The following criteria were reviewed in each patient: age, gender, race, prematurity, weight during tracheotomy, presence of preoperative airway support, duration of tracheotomy, nature (emergent versus elective), tracheotomy tube size, reason for tracheotomy, accompanying medical diagnoses, chest x-ray (CXR) findings, surgical service, postoperative symptoms (up to 3 days), and operative mortality rate. Of these criteria, our results show that CXR-screenable complications occurred in patients who underwent emergent recannulation, as well as those who exhibited ventilatory distress (oxygen saturation level of <90%) and specific changes in postoperative symptoms. Pneumothorax developed after tracheotomy in 3 of the 101 patients; each had one of these risk factors. We conclude that CXR of all pediatric patients after tracheotomy may be unnecessary with the use of flexible endoscopy and screening restrictions that are both health-conscious and cost-effective.

Adolescent↗
PubMed2000

Management of hepatic venous obstruction after split-liver transplantation.

Stenosis of the hepatic vein anastomosis is an unusual but critical complication after liver transplantation. In pediatric liver transplantation, the scarcity of size-matched donors has required the use of segmental liver allografts, either as reduced-size or split-liver grafts. This report illustrates the primary use of a hepatic vein stent to manage hepatic venous outflow obstruction in a pediatric split-liver recipient, and reviews experience in the management of hepatic venous outflow obstruction after liver transplant using stent methods.

Carcinoma, Hepatocellular↗
PubMed2000

Use of indium-111-labeled hepatocytes to determine the biodistribution of transplanted hepatocytes through portal vein infusion.

PURPOSE: Hepatocyte transplantation is useful for ex vivo gene therapy and liver repopulation. Methods for hepatic reconstitution were recently developed, but hepatocyte transplantation systems must be optimized. The authors report their experience with In-111 oxyquinolone labeling of a test dose of hepatocytes (108 cells) for noninvasive assessment of the biodistribution of transplanted hepatocytes in a 5-year-old child with omithine transcarbamoylase deficiency. MATERIALS AND METHODS: Donor hepatocytes (approximately 108) were radiolabeled using a commercially available In-111 oxyquinolone solution (specific activity of 1 mCi/ml). RESULTS: The overall labeling efficiency was 36.4%. A final dose of approximately 290 ,uCi of the In-111-labeled hepatocytes in 10 ml serum-free phosphate-buffered saline was infused percutaneously into the portal vein approximately 2.5 hours after their preparation. The study was performed 3 hours before cell transplantation (109 cells). Quantitative analysis of the biodistribution of In-111-labeled hepatocytes indicated that cells were predominantly localized in the liver immediately after portal vein-infused transplantation. The predominant hepatic distribution was persistent for as long as 7 days after the procedure, with an average liver-to-spleen ratio of 9.5 to 1. No significant pulmonary radiotracer uptake was present. CONCLUSION: These results indicate that In-111 labeling of hepatocytes is useful for the short-term noninvasive analysis of the biodistribution of transplanted hepatocytes.

Cell Movement↗
PubMed2000

Use of intrahepatic chemotherapy to treat advanced pediatric hepatic malignancies.

BACKGROUND: To evaluate the effect of intrahepatic arterial chemotherapy (IAC) on children with primary hepatic malignancies. METHOD: A nonrandomized inception cohort of 11 pediatric patients was referred for treatment of advanced primary hepatic malignancies at Children's Hospital of Pittsburgh. None of the patients was a candidate for resection before the initiation of IAC. Tumor response to treatment was observed by determining serum alpha-fetoprotein (AFP) levels and by abdominal computed tomographic scan. The patients received hepatic artery infusions of cisplatin and/or doxorubicin. The last five also received gelfoam embolization. RESULTS: Eight of 11 patients had multiple IAC treatments. Eight patients had AFP-producing tumors, and five of the eight had dramatic reductions in serum levels after IAC treatment. Five of the 11 patients underwent successful orthotopic liver transplantation after receiving IAC therapy, and the five explanted specimens showed varying degrees of tumor necrosis. One-year survival in patients in the authors' center is 67% for those with hepatoblastoma and 40% for those with hepatocellular carcinoma. Three-year survival is 60% and 30% for patients with hepatoblastoma and hepatocellular carcinoma, respectively. CONCLUSION: Intrahepatic arterial chemotherapy therapy can halt the progression and possibly down-stage advanced pediatric hepatic malignancies. This therapy can also be used as a successful adjunct in altering a patient's chance for successful liver transplantation.

Adolescent↗
PubMed1998

Orbital hydrocephalus: a proven cause for optic atrophy.

A 4-year-old boy with bilateral optic sheath enlargement and progressive optic atrophy and blindness is presented. Computed tomography demonstrated hydrocephalus and enlargement of the optic nerve sheath complex. The child died during an attempted repair of hypoplastic atrioventricular valves. Autopsy demonstrated a patulous perioptic subarachnoid space and optic atrophy. This condition has been described in the literature but has not had radiologic-pathologic correlation. With the availability of magnetic resonance imaging, this diagnosis may be made prospectively, thus, it is important for the radiologist to be aware of this entity because optic atrophy and blindness may be prevented by early diagnosis and surgery.

Abnormalities, Multiple↗
PubMed1998

Intracranial volume in craniosynostotic rabbits.

Although craniosynostosis alters brain growth direction resulting in compensatory changes in the neurocranium, it has been suggested that such compensations occur with little reduction in intracranial volume (ICV). This hypothesis was tested in a rabbit model with nonsyndromic, familial coronal suture synostosis. Cross-sectional three-dimensional computed tomographic head scans were obtained from 79 rabbits (25 normal, 28 with delayed-onset synostosis, and 26 with early-onset synostosis) at 25, 42, and 126 days of age. Intracranial contents were reconstructed and indirect ICV was calculated. Results revealed that by 25 days of age the intracranial contents from early-onset synostosed rabbit skulls showed rostral (anterior) constrictions and a "beaten copper" morphology in the parietal and temporal regions compared with the other two groups. These deformities increased in severity with age. Quantitatively, ICV was significantly reduced (P < 0.05) by 7% in rabbits with early-onset synostosis compared with both control rabbits and rabbits with delayed-onset synostosis at 25 days of age. By 126 days of age, ICV in rabbits with synostosis was significantly reduced (p < 0.05) by 11% in early-onset synostosis and by 8% in delayed-onset synostosis compared with normal rabbits. Results suggest that in rabbits with uncorrected craniosynostosis, compensatory changes in the neurocranium were not adequate to allow normal expansion of the neurocapsular matrix. Further research is needed to determine if ICV reduction is correlated with cerebral atrophy or cerebral spinal fluid (i.e., ventricular or subarachnoid) space compression in this model.

Age of Onset↗
PubMed1997

Age related changes in intracranial volume in rabbits with craniosynostosis.

Neurocapsular growth is highly heritable and determines neurocranial form. Although craniosynostosis alters brain growth direction, resulting in compensatory changes in the neurocranium, it is believed that such compensations occur without reduction in intracranial volume. This hypothesis was tested in a rabbit model with nonsyndromic, familial coronal suture synostosis. Skulls of 56 rabbits (20 normals, 20 with delayed onset synostosis, and 16 with complete synostosis) were scanned using three-dimensional computed tomography at 6 and 18 weeks of age. Intracranial contents were reconstructed, and indirect intracranial volume was calculated. Qualitatively, re-formations of intracranial contents from completely synostosed rabbit skulls exhibited the typical "copper beaten" morphology. Quantitatively, intracranial volume was significantly (p < 0.05) reduced in rabbit skulls with complete synostosis compared with both control rabbit skulls and rabbit skulls with delayed onset synostosis at 6 weeks by 11 percent and 14 percent, respectively). By 18 weeks, intracranial volume in rabbit skulls with synostosis was significantly (p < 0.05) reduced (by 12 percent in complete synostosis and 8 percent in delayed onset synostosis) compared with normal rabbits. Results suggest that in rabbits with uncorrected craniosynostosis, compensatory changes in the neurocranium were not adequate to allow normal expansion of the neurocapsular matrix. Further research is needed to determine whether reduction in intracranial volume was a result of neural tissue deficiency or cerebrospinal fluid (i.e., ventricular or subarachnoid) space compression in this model.

Aging↗
PubMed1995

Evaluation and management of bilateral renal artery stenosis in children: a case series and review.

This report describes the clinical course, diagnostic evaluation and management of six children with bilateral renal artery stenosis (RAS) and concurrent narrowing of the abdominal aorta. Except for one child with active arteritis, the others were asymptomatic. There were no clinical or laboratory features suggesting the etiology of hypertension in four of six patients, and diagnostic procedures, including Doppler duplex ultrasound and captopril scintigraphy, were unreliable in screening for such hypertension. Abdominal aortography and selective renal angiography confirmed the diagnosis of bilateral RAS and associated anatomical alterations of the aorta and its branches. The hypertension was severe and minimally responsive to antihypertensive agents. It was cured or improved after percutaneous transluminal angioplasty (PTA) of three vessels in two children with mid-vessel stenoses, while hypertension persisted after PTA of two mid-vessel stenoses in a third child and one vessel with ostium stenosis in a fourth child. Autotransplantation of seven kidneys in four children resulted in cure of significant improvement of the hypertension. Renal function was preserved in all children during a mean follow-up time of 41 months. Based on illustrative data from these six children, as well as information from a review of the literature, this report discusses the key diagnostic issues and stresses the potential advantages of renal autotransplantation in selected children with this disorder.

Adolescent↗
PubMed1995

Mutism and pseudobulbar symptoms after resection of posterior fossa tumors in children: incidence and pathophysiology.

MUTISM AND A variety of other neurobehavioral symptoms have been reported anecdotally after the removal of posterior fossa mass lesions. To determine the incidence and clinical spectrum of this syndrome, a detailed review was performed of patients undergoing resection of infratentorial tumors at our institution during the last 9 years; 12 of 142 patients (8.5%) manifested this syndrome, the largest series of such patients reported to date. Each child had a lesion that involved the vermis; seven had medulloblastomas, three had astrocytomas, and two had ependymomas. The incidence among children with vermian neoplasms was 13%. Ten children underwent division of the inferior vermis during tumor resection, and three had a superior vermian incision; one child underwent both superior and inferior vermian incisions. In 10 children, mutism developed in a delayed fashion postoperatively. The speech disturbance was associated with poor oral intake in 9 children, urinary retention in 5, long-tract signs in 6, and bizarre personality changes, emotional lability, and/or decreased initiation of voluntary movements in all 12. Neuropsychiatric testing, performed in seven children, confirmed impairments not only in speech but also in initiation of other motor activities. Ten children regained normal speech, bladder control, and neurological functioning, other than ataxia and mild dysarthria, within 1 to 16 weeks; two children had significant residual deficits. Characteristically, affect and oral intake returned to their preoperative baseline before the speech difficulties began to resolve. A detailed radiological review of these cases in parallel with 24 cases of vermian tumors without mutism identified only one factor that was significantly associated with the mutism syndrome, bilateral edema within the brachium pontis (P < 0.01). Neither the size of the tumor nor the length of vermian incision was associated with the development of mutism. The clinical features of this syndrome in the context of these imaging findings suggest that the mutism syndrome results from transient impairment of the afferent and/or efferent pathways of the dendate nuclei that are involved in initiating complex volitional movements. The clinical courses of our patients are presented and compared with those of similar cases in the literature in an attempt to evaluate the validity of this hypothesis.

Adolescent↗
PubMed1995

Osteoid osteoma: percutaneous excision using a CT-guided coaxial technique.

OBJECTIVE: We describe a coaxial technique for percutaneous, CT-guided removal of osteoid osteoma in children. SUBJECTS AND METHODS: The study included eight children aged 3 years to 15 years 9 months who had signs and symptoms of osteoid osteoma. The diagnoses were confirmed by CT scans. Seven of nine lesions were removed manually with a coaxial technique and a trephine. Power tools were added to the technique in the other two cases. Removal of the nidus was confirmed by postprocedural CT scans and by histologic examination. RESULTS: All CT-guided excisions were technically successful, and only one minor complication occurred. One recurrence at 13 months was successfully treated percutaneously. CONCLUSION: CT-guided coaxial removal of osteoid osteoma is a safe and effective treatment. Increasing experience and the use of power tools in selected cases helps to shorten the procedure.

Adolescent↗
PubMed1995

Bobble-head doll syndrome and drop attacks in a child with a cystic choroid plexus papilloma of the third ventricle. Case report.

The authors report an unusual case of a 2-year-old boy with a 3-month history of episodic rightward anterolateral head tilt and large-amplitude positional anteroposterior head bobbing reminiscent of bobble-head doll syndrome. This child experienced a sudden onset of drop attacks and then, within several hours, deep coma. The causative lesion was a contrast-enhancing, partially cystic third ventricular mass, which ultimately obstructed the aqueduct, producing profound obstructive hydrocephalus. An emergency ventriculostomy and endoscopic fenestration of the septum pellucidum was performed. Four days later, the tumor was completely resected by a transcallosal-transforaminal approach. The lesion was freely mobile within the third ventricle and contained a large cyst within its posterior pole; following drainage of the cyst, the lesion was easily delivered through the foramen of Monro. The histopathological diagnosis was choroid plexus papilloma. The child's neurological deficits, head tilt, and head bobbing resolved immediately after operation. To the best of the authors' knowledge, this represents the first well-documented report of bobble-head doll syndrome and drop attacks secondary to a choroid plexus papilloma. The highly mobile nature of the cystic lesion presumably led to its intermittent impaction within the foramen of Monro and/or proximal aqueduct; this produced the intermittent head tilt and bobble-head symptoms and, ultimately, resulted in acute obstruction of the aqueduct, causing the child's precipitous neurological decline.

Brain Neoplasms↗
PubMed1995

What's new in interventional radiology.

New applications of interventional radiology can remove foreign bodies from the esophagus, treat vascular malformations, and more. These relatively noninvasive and inexpensive alternatives to conventional surgery deserve a place on your list of management options.

Bone Neoplasms↗
PubMed1993

Intervention in the thorax in children.

The 1970s and 1980s have been a period of significant growth and innovation in interventional radiology. Interventional procedures that were developed and perfected with adult patients are now being used very successfully in pediatric patients. In comparison with surgical management, interventional procedures generally have lower morbidity and mortality, require shorter hospital stays, and are less expensive. Preprocedural imaging and planning, adequate monitoring and sedation during the procedure, and selection of equipment appropriate for pediatric patients maximizes the chance for a successful outcome.

Child↗
PubMed1992

Interventional procedures in pediatrics.

Pediatric intervention has grown substantially over the last 20 years. Interventionalists now work closely with surgeons and other physician groups to diagnose and treat a wide variety of pediatric disease processes. Using image guidance and intravenous sedation in most instances, the interventionalist performs vascular and nonvascular procedures such as embolotherapy, abscess drainage, dilation of strictures, biopsy, and percutaneous nutritional procedures, to name a few. It is my hope that the current and future techniques will lead to improved, more effective, and safer methods for treating sick children of all ages.

Angioplasty, Balloon↗
PubMed1991

Comparison of iohexol with barium in gastrointestinal studies of infants and children.

This study evaluates iohexol as a contrast agent in the gastrointestinal tract in children. In the first part of the study, iohexol in concentrations of 180 and 300 mg l/ml was compared in double-blind manner with barium. Sixty-four patients were studied. No significant difference in changes of blood pressure and pulse rate was found between the three groups of patients studied. Diarrhea was significantly more common in the children receiving iohexol than in children receiving barium. The diarrhea was not due to previously identified high-risk factors in the children, nor was it due to concurrent medication. When image quality was assessed in each anatomic region of the gastrointestinal tract, fewer nondiagnostic ratings occurred with barium than with iohexol. With barium, fewer ratings of poor mucosal coating and slightly fewer ratings of suboptimal contrast density occurred. The second part of the study was an open evaluation of iohexol 180 mg l/ml in 18 patients in whom barium was clinically contraindicated. Three of 53 assessments were nondiagnostic. Mucosal coating was poor in 6%, and contrast density was suboptimal in 8% of patients. The results of this study indicate that barium is the preferred contrast agent for routine evaluation of the gastrointestinal tract in children. Good-quality images can be obtained, however, with iohexol in concentrations of 180 or 300 mg l/ml, and iohexol is an excellent contrast agent for evaluation of the gastrointestinal tract in those patients in whom barium is relatively or absolutely contraindicated.

Adolescent↗
PubMed1991

Instability of the cervical spine after decompression in patients who have Arnold-Chiari malformation.

Stability of the cervical spine was studied in two groups of children who had myelomeningocele. Group I consisted of twenty children who had an Arnold-Chiari Type-II malformation in whom a suboccipital craniectomy (partial occipital craniectomy through the suboccipital route) and cervical laminectomy was done to decompress the brain stem. The average duration of follow-up in this group (excluding one patient) was 4.7 years (range, 2.3 to 10.4 years) after the operation. Group II consisted of twenty children who had myelomeningocele but had not had an operation for decompression. Lateral radiographs of the cervical spine in flexion and extension showed no instability between the occiput and atlas or between the atlas and axis in either group. In contrast, translation between the second and third cervical vertebrae averaged four millimeters in Group I and one millimeter in Group II (p less than 0.01), and angulation between the third and fourth cervical vertebrae averaged 17 degrees in Group I and 6 degrees in Group II (p less than 0.01). Nineteen of the twenty patients in whom a suboccipital craniectomy and cervical laminectomy (Group I) had been done had instability of the cervical spine.

Arnold-Chiari Malformation↗