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Biomedical subjects

T S Roberts

Publications and source records attributed to T S Roberts.

At least 19 recordsLinked to original sources
PubMed2006

Osteoglophonic dysplasia: dental and orthodontic implications.

AIMS AND OBJECTIVES: Documentation of dental and orthodontic implications of osteoglophonic dysplasia (OGD). SETTINGS AND PARTICIPANTS: Case report describing oral and dental manifestations of a female with OGD, aged 39 years, who was first documented three decades ago. RESULTS: This rare genetic disorder manifests with gross stunting of stature, associated with severe craniofacial malformation and multiple unerupted teeth. Radiographically, multiple lucent lesions were present in the tubular bones and mandible as well as several impacted teeth. CONCLUSION: We concluded that prosthetic dental replacement in this patient would be difficult because of the distorted jaw relationship and large alveolar ridges. Equally, craniofacial reconstruction might be compromised by obstruction of the nasal airways, difficulty in intubation and postoperative respiratory problems.

Adult↗
PubMed2001

O6-Methylguanine-DNA methyltransferase in pediatric primary brain tumors: relation to patient and tumor characteristics.

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) confers resistance to methylating and chloroethylating agents in pediatric medulloblastoma- and glioma-derived cell lines and xenografts. Here, we assayed MGMT activity in 110 pediatric brain tumors to establish correlates with patient and tumor characteristics. We also assayed MGMT in histologically normal brain adjacent to 22 tumors to characterize changes in activity accompanying neurocarcinogenesis. MGMT activity was detected in 94% of tumors, ranging ca. 1,500-fold from 0.34 to 498 fmol/10(6) cells (approximately 205-300,000 molecules/cell). Mean activity was 25 +/- 66 fmol/10(6) cells, including six specimens with undetectable activity (Mer- phenotype; <0.25 fmol/10(6) cells or 151 molecules/cell). MGMT content varied 10-fold among diagnostic groups and was associated with degree of malignancy, as evidenced by a 4-fold difference in activity between high- and low-grade tumors (P = 0.03). Tumor MGMT content was age dependent, being 5-fold higher in children 3-12 years old than in infants (P = 0.015) and adolescents (P = 0.015). Mean activity in tumors was 9-fold higher than in adjacent histologically normal brain (21 +/- 44 versus 2.4 +/- 4.0 fmol/10(6) cells; P = 0.05). By comparing tumor and adjacent normal tissue from the same patient, we found that 68% of cases exhibited an elevation of tumor activity that ranged from 2- to >590-fold. Moreover, 67% of Mer- normal tissue was accompanied by Mer+ tumor. These observations indicate that MGMT activity is frequently elevated during pediatric neurocarcinogenesis. Significantly, enhanced MGMT activity may heighten resistance to alkylating agents, suggesting a potential role for MGMT inhibitors in therapy.

Adolescent↗
PubMed1999

Spontaneous resolution of a cervicothoracic syrinx in a child. Case report and review of the literature.

A child with near complete spontaneous resolution of a cervicothoracic syrinx and improvement in a Chiari type I malformation without surgical intervention is presented. The child was followed clinically with serial magnetic resonance (MR) imaging and has remained neurologically stable over an 11-year period. To our knowledge, only 3 pediatric cases of spontaneous resolution of a spinal cord syrinx as documented by MR imaging without surgical intervention have been reported. This case contributes to the literature on the natural history of syringes.

Abnormalities, Multiple↗
PubMed1999

Symptomatic moyamoya disease and aortic coarctation in a patient with Noonan's syndrome: strategies for management.

Noonan's syndrome is a multiple congenital anomaly syndrome with characteristic facial features, short stature, congenital heart defects and a recently reported association with moyamoya disease. We report a case of symptomatic moyamoya disease and aortic coarctation in a patient with Noonan's syndrome. The case illustrates the need for a rational, coordinated treatment plan for dealing with the cardiac and neurologic syndromic anomalies to help avoid undesirable outcomes.

Aortic Coarctation↗
PubMed1999

Management of intrinsic gliomas of the tectal plate in children. A ten-year review.

The natural history, management, and long-term outcome for patients with benign, intrinsic tectal plate gliomas remain controversial in spite of their propensity to cause late-onset hydrocephalus. A 10-year retrospective review has identified 11 consecutive children with tectal plate lesions. Headache, vomiting, a decline in school performance, tremor, and complex partial seizures were common presenting symptoms. All patients presented with signs and symptoms of hydrocephalus. Magnetic resonance (MR) imaging delineated an intra-axial mass lesion of the midbrain primarily localized to the tectal plate which uniformly was hyperintense on T2-weighted imaging and had a more variable appearance on T1-weighted imaging and rare enhancement with gadolinium. No patient underwent surgical resection, chemotherapy, or radiotherapy. Three of 11 patients (27%) showed evidence of progression in size or a new focus of enhancement on MR imaging, which was clinically asymptomatic. In this series, no patient with a tectal plate lesion less than 1.5 cm in maximal diameter and without gadolinium enhancement showed any evidence of clinical or radiological progression. Although intrinsic tectal lesions in children are clinically indolent and the initial management consists of CSF diversion, these lesions may eventually progress and still warrant long-term follow-up with serial MR imaging.

Brain Stem Neoplasms↗
PubMed1998

Selective dorsal rhizotomy: efficacy and safety in an investigator-masked randomized clinical trial.

The objective of this single-center investigator-masked randomized clinical trial was to investigate the efficacy and safety of selective dorsal rhizotomy (SDR) in children with spastic diplegia. Forty-three children with spastic diplegia were randomly assigned on an intention-to-treat basis to receive SDR plus physical therapy (PT), or PT alone. Thirty-eight children completed follow-up through 24 months. Twenty-one children received SDR (SDR+PT group) and 17 received PT (PT Only group). SDR was guided with electrophysiological monitoring and performed by one experienced neurosurgeon. All subjects received equivalent PT. Spasticity was quantified with an electromechanical torque measurement device (spasticity measurement system [SMS]). The Gross Motor Function Measure (GMFM) was used to document changes in functional mobility. Primary outcome measures were collected at baseline, 6, 12, and 24 months by evaluators masked to treatment. At 24 months, the SDR+PT group exceeded the PT Only group in mean reduction of spasticity by SMS measurement (-8.2 versus +5.1 newton meters/radian, P=0.02). The SDR+PT group and the PT Only group demonstrated similar improvements in independent mobility on the GMFM (7.0 versus 7.2 total percent score, P=0.94). Outcomes on secondary variables were consistent with primary outcomes. There were no serious adverse events. We conclude that SDR is safe and reduces spasticity in children with spastic diplegia. SDR plus PT and equivalent PT without SDR result in equal improvements in independent mobility at 24 months. SDR may not be an efficacious treatment for children with mild spastic diplegia.

Adolescent↗
PubMed1998

Electrophysiological monitoring during selective dorsal rhizotomy, and spasticity and GMFM performance.

The relation between abnormal electrophysiological responses to intraoperative stimulation during selective dorsal rhizotomy (SDR) and the degree of spasticity and motor dysfunction was explored in 92 children with spastic cerebral palsy (CP) who underwent SDR at a single center. The proportion of abnormally responding rootlets was compared with the degree of spasticity measured with the modified Ashworth Scale (MAS) and with the spasticity measurement system (SMS) at discrete segmental levels. Motor impairment measured with the Gross Motor Function Measure (GMFM) was also compared with the proportion of abnormally responding dorsal rootlets. A consistent relation between the proportion of abnormally responding rootlets and the degree of spasticity and gross motor abnormality at the corresponding muscles could not be demonstrated. There was also no consistent association between the proportion of rootlets ablated during SDR and the change in spasticity measured with the MAS and SMS, or to the change in motor function as measured with the GMFM. These data suggest that the intraoperative monitoring technique most commonly used for SDR is unlikely to identify accurately those neural elements which contribute to spasticity in children with CP.

Adolescent↗
PubMed1997

Acquired hydrocephalus associated with superior vena cava syndrome in infants.

We report observations on children with the unusual combination of superior vena cava syndrome in infancy followed by communicating hydrocephalus. Following retrospective review of hospital discharges at a tertiary children's hospital, three children were identified in a 13-year period. Two term infants were treated with extracorporeal membrane oxygenation for pulmonary failure associated with congenital diaphragmatic hernia. These infants had septic complications of central venous lines. A post-term infant required reconstruction of the superior vena cava following cannulation for cardiac bypass surgery to repair transposition of the great vessels. Thrombosis occurred and was followed by the sequential development of superior vena cava syndrome and communicating hydrocephalus. The findings in these patients suggest that communicating hydrocephalus may be caused by superior vena cava syndrome. This is an unusual complication of therapeutic manipulation of the heart and great veins. Cerebrospinal fluid shunting may be required.

Extracorporeal Membrane Oxygenation↗
PubMed1996

The differential diagnosis of posterior plagiocephaly: true lambdoid synostosis versus positional molding.

The diagnosis and treatment of posterior plagiocephaly is one of the most controversial aspects of craniofacial surgery. The features of true lambdoid synostosis versus those of deformational plagiocephaly secondary to positional molding are inadequately described in the literature and poorly understood. This has resulted in many infants in several craniofacial centers across the United States undergoing major intracranial procedures for non-synostotic plagiocephaly. The purpose of this study was to describe the detailed clinical, imaging, and operative features of true lambdoid synostosis and contrast them with the features of positional plagiocephaly. During a 4-year period from 1991 to 1994, 102 patients with posterior plagiocephaly were assessed in a large multidisciplinary craniofacial program. During the same period, 130 patients with craniosynostosis received surgical treatment. All patients were examined by a pediatric dysmorphologist, craniofacial surgeon, and pediatric neurosurgeon. Diagnostic imaging was performed where indicated. Patients diagnosed with lambdoid synostosis and severe and progressive positional molding underwent surgical correction using standard craniofacial techniques. Only 4 patients manifested the clinical, imaging, and operative features of unilambdoid synostosis, giving an incidence among all cases of craniosynostosis of 3.1 percent. Only 3 among the 98 patients with positional molding required surgical intervention. All the patients with unilambdoid synostosis had a thick ridge over the fused suture, identical to that found in other forms of craniosynostosis, with compensatory contralateral parietal and frontal bossing and an ipsilateral occipitomastoid bulge. The skull base had an ipsilateral inferior tilt, with a corresponding inferior and posterior displacement of the ipsilateral ear. These characteristics were completely opposite to the findings in the 98 patients who had positional molding with open lambdoid sutures and prove conclusively that true unilambdoid synostosis exists as a specific but rare entity. Awareness of the features of unilambdoid synostosis will allow more accurate diagnosis and appropriate treatment of posterior plagiocephaly in general and in particular will avoid unnecessary surgical intervention in patients with positional molding.

Cranial Sutures↗
PubMed1996

Intracranial and extracranial reduction osteoplasty for craniodiaphyseal dysplasia.

Craniodiaphyseal dysplasia is a rare, sporadic form of craniotubular bone dysplasia, characterized by massive generalized hyperostosis and sclerosis, particularly of the skull and facial bones, leading to severe deformity. The clinical course is typically characterized by progressive encroachment of the craniofacial foramina and brain by the relentless deposition of bone. Compression of cranial nerves, the foramen magnum, and intracranial contents commonly leads to blindness, loss of hearing, and death. This report describes a unique case of craniodiaphyseal dysplasia manifesting with asymmetric craniofacial and axial hyperostosis. The tubular bones demonstrated the characteristic diaphyseal endostosis, undertubulation, and relative overgrowth on the involved side. Significant brain compression with signs and symptoms of increased intracranial pressure was managed successfully with decompressing craniectomy at age 12 years, enlarging the anterior and middle fossae. Calvarial thickness measured nearly 4 cm. Further calvarial, midfacial, and mandibular recontouring were performed 6 and 22 months later. Follow-up in our case indicates that close observation is mandatory to manage further progression of the disease.

Bone Diseases, Developmental↗
PubMed1995

Orthopedic management of knee dislocations. Comparison of surgical reconstruction and immobilization.

Thirty-nine patients with 43 complete knee dislocations managed between 1973 and 1990 were reviewed retrospectively to compare the results of surgical reconstruction to nonreconstructive treatment of these injuries. The average patient age was 34 years and the average follow-up was 5 years (range: 1 to 18 years). Patients were evaluated by physical examination and the Lysholm knee scoring scale. Fourteen knees (33%) sustained popliteal vessel injury and five (9%) required amputation. Peroneal and tibial nerve injuries involved 13 knees (30%). Twenty-five of 39 patients (64%) sustained other associated fractures. Three patients sustained associated paraplegia and nine were lost to follow-up, leaving 25 knees available for follow-up examination. Thirteen knees were managed by surgical reconstruction of their ligamentous injuries and 12 were managed by nonreconstructive means. The surgically treated group had an average Lysholm knee score of 80 compared with the nonreconstructive group with an average score of 66. Average range of motion of was 106 degrees for the surgical group and 95 degrees for the nonreconstructive group. Despite the severity of the initial injury and the potential presence of vascular/nerve injuries, surgical reconstruction provides superior results to immobilization alone in the management of these injuries.

Adolescent↗
PubMed1994

Pain management for children following selective dorsal rhizotomy.

Selective dorsal rhizotomy (SDR) is a neurosurgical procedure used for treating lower extremity spasticity in patients with cerebral palsy. The purpose of this paper is to present a review of our institution's first three years' experience with postoperative pain and spasticity management in patients who have undergone SDR. The medical records of the 55 patients who had an SDR during the study period were reviewed. The basis of postoperative analgesia was morphine, with the majority of patients receiving continuous morphine infusions (20-40 micrograms.kg-1.hr-1 (n = 49), 60 micrograms.kg-1.hr-1 (n = 1)). Four patients used a patient-controlled delivery system. One patient had successful analgesia with epidural morphine. Ketorolac (1 mg.kg-1 i.v. loading dose followed by 0.5 mg.kg-1 i.v. every six hr for 48 hr) was used as an adjunct to morphine in six patients. For management of postoperative muscle spasm, an intravenous benzodiazepine was used (diazepam 0.1 mg.kg-1 (n = 2), or midazolam infusion 10-30 micrograms.kg-1.hr-1 (n = 51)). All patients were cared for on a ward where nurses were familiar with the use of continuous opioid and benzodiazepine infusions. All patients received continuous cardiorespiratory monitoring as well as frequent nursing assessment. There were no episodes of postoperative apnoea or excessive sedation. We have found the use of continuous infusions of morphine and midazolam, along with adjunct ketorolac, to be effective in treating postoperative pain and muscle spasms following SDR.

Adolescent↗
PubMed1994

The role of selective dorsal rhizotomy in cerebral palsy: critical evaluation of a prospective clinical series.

This is a prospective observational study of a consecutive series of 34 children with spastic cerebral palsy treated at a single center. 10 had spastic quadriplegia and 24 had spastic diplegia. All were followed for at least one year. After selective dorsal rhizotomy (SDR), all children received one month of physical therapy at the center and were prescribed a program of physical therapy in their community. The children were assessed before and one year after SDR and physical therapy, using the Ashworth Scale, deep tendon reflex response, range of motion and the Gross Motor Function Measure. The results show that there is often a decrease in lower-extremity spasticity and functional improvement after SDR with physical therapy, but that there is considerable variability in outcome. Randomized prospective clinical trials with masked objective outcome measures are needed to determine the efficacy of SDR.

Cerebral Palsy↗