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Biomedical subjects

C Teo

Publications and source records attributed to C Teo.

At least 37 records · Page 2Linked to original sources
PubMed1997

The Chiari II malformation: a surgical series.

Thirty patients between the ages of 7 months and 24 years were treated surgically for symptomatic Chiari II malformation at the Arkansas Children's Hospital. All patients underwent at least bony decompression of the malformation. Assessments of the patients' conditions were made at 6 weeks and 1 year after surgery, and complications of surgery were noted. For a majority of the patients, the presenting symptoms were resolved following treatment (74% at 6 weeks and 80% at 1 year). Partial resolution occurred in several of the patients (17% at 6 weeks and 14% at 1 year). A small number remained the same at 6 weeks (6%) and at 1 year (3%), while 1 patient was worse after surgery. Ten of the patients with complete resolution in the short term required repeat surgery an average of 49 months after their original operation, after which they again attained complete resolution of their symptoms. Scales for clinical, radiographic and operative grading of the patients' conditions as mild, moderate or severe were devised, and these were employed to characterize the condition of each patient. Patients in each grading category had good results, with rates of complete symptomatic resolution ranging from 67 to 100%. Severity in each category was found to be well correlated with eventual recurrence of symptoms and need for reoperation.

Adolescent↗
PubMed1997

Neuroendoscopy: current applications and future directions.

Endoscopy is ideally suited to any organ that is hollow and fluid filled. The ventricular system, although only 10% of the total intracranial volume, is the site of many pathological processes. It is filled with crystal clear cerebrospinal fluid and lined thoughout by ependyma. Unfortunately access to it is invariably through normal brain tissue, but morbidity can be limited by choosing areas that are not as eloquent as others. The size of the ventricles limits the type of scope and instrumentation that can be used, but as technology advances these limitations are diminishing.

Journal Article↗
PubMed1996

Construction of a vein-pouch aneurysm at a surgically created carotid bifurcation in the rat.

Currently available animal models for the study of treatment of aneurysms are either expensive or yield unreliable results. An animal series was devised to address both of these problems by creating a new animal model. Twelve Sprague-Dawley rats were used to demonstrate that a vein-pouch aneurysm could be constructed at a surgically created carotid bifurcation. Patency rates, growth dynamics, and histologic morphology were studied at three time intervals. A 100% patency rate at the aneurysm orifice was achieved with one-third of the aneurysms showing varying degrees of partial apical thrombosis. A growth pattern was established over the study period. Magnetic resonance angiography and digital subtraction angiography were successfully employed to study a small number of additional aneurysms. Our conclusion is that a bifurcation aneurysm can be constructed in the rat with high patency rates and predictable saccular morphology which resembles most human intracranial aneurysms. This inexpensive animal model can be used to study novel modalities for the treatment of aneurysms.

Anastomosis, Surgical↗
PubMed1996

Complications of endoscopic neurosurgery.

Neuroendoscopy is rapidly becoming an essential part of the neurosurgeon's repertoire. Currently, very few studies have identified the complications of this new technique, yet many have warned of the steep learning curve associated with its practice. We have reviewed the last 173 neuroendoscopic procedures performed by one surgeon and identified two distinct groups of complications: those that have clinically significant sequelae and those that cause concern intraoperatively but no overt clinical problems. The 173 procedures were performed on 152 patients. Of these patients, 11 suffered significant complications (7%). Twenty-two of the procedures were complicated by intraoperative problems (13%). The incidence of insignificant complications appeared to decrease with experience, whereas that of the significant ones did not. These complications occurred in association with a wide variety of operations over a 2-year period. We conclude that neuroendoscopy is a relatively safe technique with an overall 7% complication rate and a steep learning curve, and that, with a few simple guidelines, it can be employed by all neurosurgeons for the betterment of their patients.

Adolescent↗
PubMed1996

Telomeric associations in the progression of chromosome aberrations in pediatric solid tumors.

Telomeric association (tas) is a cytogenetic phenomenon in which chromosome ends fuse to form dicentric, multicentric, and ring chromosomes. We observed clonal tas in six pediatric solid tumors of various types and histological grades studied using short-term in situ culture and G-banding techniques. These tumors included a neurilemoma, an undifferentiated (embryonal) sarcoma of the liver (UESL), two anaplastic astrocytomas (AA), one case of glioblastoma multiforme (GBM), and a neuroblastoma (NB) of the kidney. Cytogenetic data from all six tumors demonstrated multiple numerical and structural aberrations including tas. The tas appeared to be a secondary aberration in these tumors, however, it was possible to follow the progression of the telomeric chromosome aberrations in several cases. In all but one case (UESL) the loss of chromosome segments occurred. Tas of 11p was observed in three of the six tumors, two of which showed the subsequent loss of 11p (AA and AB). In addition, tas of 4p was seen in three tumors, two of which showed clonal tas of 4p with 22q. Tas of 10p, 21p, and 22q were all observed in at least two different tumors. The clonal telomeric fusions of 4p with 22q, recurring tas of 11p, and the subsequent loss of the short arm of 11 demonstrated here, suggests that some chromosome regions are subject to nonrandom instability and sometimes loss.

Adolescent↗
PubMed1996

Management of hydrocephalus by endoscopic third ventriculostomy in patients with myelomeningocele.

Endoscopic third ventriculostomy (ETV) was performed between July 1978 and July 1995 on 69 patients with hydrocephalus and myelomeningocele. Most of the patients had been previously shunted, although in 14 patients ETV was the initial treatment. Patient selection was based on preoperative imaging studies suggesting noncommunicating hydrocephalus. Only 2 patients exhibited transient hypothalamic dysfunction with complete resolution. Patients were assessed by their clinical status, imaging characteristics, and, in some cases, formal psychometric studies. The overall success rate was 72%, although selecting only patients who have been previously shunted or who were over 6 months of age at the time of endoscopy increases this to 80%. Our results indicate that ETV is a safe and effective means of treating hydrocephalus in the older spina bifida population and offers the hope of long-term, shunt-independent life for selected patients.

Adolescent↗
PubMed1996

Outcome analysis of 85 patients undergoing the pi procedure for correction of sagittal synostosis.

The authors present a retrospective review of their experience with 85 cases using the pi procedure to correct sagittal synostosis. A male preponderance of four to one was recognized in this group. Sixty-five infants underwent computerized tomography scanning of the head prior to surgery; these scans revealed unexpected intracranial pathology in 5% of cases. Surgical complications included three intraoperative dural lacerations. All children received blood transfusions with no complications. Cosmetic outcomes were excellent in 53%, good in 43%, and poor in 4% of cases. One patient required reoperation. All poor outcomes were in infants who were younger than 8 weeks of age at the time of surgery and who underwent a "reverse pi" procedure. Most of the excellent outcomes occurred in infants who were between 3 and 6 months of age at the time of surgery. Although more extensive than strip craniectomy, the pi procedure can be accomplished with minimal morbidity. In the authors' opinion, the pi procedure provides better immediate and long-term cosmetic results than synostectomy alone.

Age Distribution↗
PubMed1995

Ventriculosubgaleal shunt: a treatment option for progressive posthemorrhagic hydrocephalus.

Among premature infants born at less than 1500 g, the incidence of intraventricular hemorrhage is greater than 45%. Of these, 40% will develop progressive posthemorrhagic hydrocephalus (PPHH). Optimum treatment remains controversial. Ventriculosubgaleal (VSG) shunts were first proposed as a means of temporarily diverting cerebrospinal fluid (CSF) in a more physiological manner for those infants less than 1500 g in weight who would not tolerate a ventriculoperitoneal (VP) shunt. The VSG shunt could then be converted into a VP shunt when the infant had gained the desired weight. Despite favourable reports, the procedure has not gained universal acceptance and is unknown to many neurosurgeons. The present authors report a series of 15 patients who had VSG shunts inserted with excellent temporary CSF diversion and no complications. Furthermore, 3 out of the 15 patients required no further treatment. We suggest that VSG shunting is a safe and effective means of treating the premature infant with PPHH.

Cerebral Hemorrhage↗
PubMed1995

Low-grade astrocytoma with a complex four-breakpoint inversion of chromosome 8 as the sole cytogenetic aberration.

We report a case of a low-grade astrocytoma in a 10-year-old boy in which the sole cytogenetic aberration was a complex four-breakpoint inversion of chromosome 8 with the karyotype designation 46,XY,der(8)inv(8)(p23q24)inv(8)(q11q21). Two protooncogenes on chromosome 8, MOS at 8q11 and MYC at 8q24, are located at or near the bands which correspond to two of the breakpoints in this inversion. The localization of the structural aberrations to four breakpoints on chromosome 8 provides a rare example of a solid tumor with structural aberrations limited to a single chromosome.

Astrocytoma↗
PubMed1995

Management of traumatic cerebrospinal fluid fistula.

Cerebrospinal fluid fistulae present a common management problem for the surgeon managing craniofacial trauma. Controversies exist concerning various aspects of treatment. These controversial management issues include cerebrospinal fluid drainage, antibiotic prophylaxis, timing of surgical intervention, and techniques of repair. Although most cerebrospinal fluid fistulae cease spontaneously, some fistulae persist, resulting in the potential for life-threatening complications. A review of these issues is presented, together with a suggested management protocol.

Algorithms↗
PubMed1991

The pseudotumor syndrome. Disorders of cerebrospinal fluid circulation causing intracranial hypertension without ventriculomegaly.

We report a series of eight cases that show a close resemblance to, but are not identical with, pseudotumor cerebri (PTC) as normally defined. The majority of these cases are characterized by raised intracranial pressure without ventriculomegaly. They include two cases of cranial venous outflow obstruction in which clinical or radiologic abnormalities precluded the diagnosis of PTC proper (cases 1 and 2); one case of chronic meningitis in which an abnormal cerebrospinal fluid (CSF) composition precluded the diagnosis of PTC (case 3); two cases without either papilledema or a measured increase of CSF pressure, which in other respects, particularly in response to treatment, resembled PTC (cases 4 and 5); and three cases of what is thought to represent an infantile form of PTC (cases 6 through 8). The purpose of the analysis of these cases is twofold. First, it is argued that these cases throw light on the mechanism of PTC itself, supporting a concept of a disturbance of CSF circulation in this condition, and that they are themselves illuminated by considerations of typical PTC. Second, the cases are used to frame a proposed classification of the pseudotumor syndrome aimed at broadening the diagnostic criteria applied currently to PTC. It is suggested that the pseudotumor syndrome has a single underlying mechanism (disturbed CSF circulation) and that recognition of this mechanism not only clarifies the pathophysiologic processes of PTC but also has important diagnostic and therapeutic implications.

Adolescent↗
PubMed1991

Human recombinant GM-CSF in allogeneic bone marrow transplantation for leukaemia: double-blind placebo controlled trial.

A double-blind randomised trial compared 20 patients with leukaemia receiving human recombinant granulocyte macrophage colony stimulating factor (GM CSF), with 20 patients receiving placebo for 14 days after allogeneic matched sibling bone marrow transplantation. The median neutrophil count at 14 days was significantly higher in the GM CSF group (1.90 vs. 0.46 x 10(9)/l). The duration of hospital stay, the number of antibiotic days, and the number of fever days was the same for both patient groups. The lymphocyte count was significantly higher in the GM-CSF group than in the placebo group between days 10 and 15 after transplantation. The GM-CSF group had lower haemoglobin concentrations and platelets counts, and higher plasma urea creatinine and bilirubin, than the placebo group. There was no evidence that GM CSF was associated with a greater incidence of leukaemic relapse.

Bone Marrow Transplantation↗
PubMed1988

Management of cerebral abscess in adolescents and adults. Experience in the CT-scan era.

Thirty-seven patients with non-traumatic intracerebral abscesses are presented. Two were not diagnosed during life. Where the possible cause could not ascertained, a metastatic origin was the commonest, followed by otogenic. A variety of causative organisms, including especially Streptococci, Staphylococci and Bacteroides were isolated. It is possible that the most effective treatment was primary excision of the abscess plus antibiotics, but the numbers were too small for a statistically significant difference to be shown. The reasons for recent improvements in outcome of brain abscesses, including more use of CT scanning and refinements in isolation of organisms and in antibiotic treatment, are discussed, along with possible steps towards more improvement in future.

Adolescent↗
PubMed1987

Incidence of motile, curved anaerobic rods (Mobiluncus species) in vaginal secretions.

Aerobic and anaerobic cultures as well as a Gram stain and wet mount preparation were made of vaginal swabs taken from various groups of women including those with vaginal discharge. The bacteria commonly found in cultures were lactobacilli, coryneforms, Staphylococcus epidermidis and facultative streptococci. Anaerobes were isolated from 75% (475 of 632) of specimens. The incidence of Trichomonas vaginalis, Candida species, Gardnerella vaginalis and Mobiluncus species in the five groups of women varied from 2.2-5.1%, 11.5-35.7%, 23.3-36.7% and 20.0-34.8% respectively. Except for Candida species, differences in the prevalence of these organisms between the groups of women were not significant. The isolation rates of Candida species in women attending the antenatal clinic and staff health clinic were significantly higher than women in the other groups. Mobiluncus species were found to occur either with T. vaginalis, Candida species or G. vaginalis alone or with any two or with all three or in the absence of these organisms. However, the incidence of Mobiluncus species was significantly higher in women colonized with G. vaginalis (112 of 185, or 60.5%) compared with women not infected (47 of 477, or 9.8%). Also, Mobiluncus species occurred in large numbers when found in the presence of G. vaginalis. When found without G. vaginalis, Mobiluncus species occurred in much smaller numbers. As with G. vaginalis, Mobiluncus species also occurred concomitantly with certain anaerobes, mainly Bacteroides species and peptostreptococci.

Animals↗