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Biomedical subjects

C Y Poon

Publications and source records attributed to C Y Poon.

14 recordsLinked to original sources
PubMed2007

The effect of prior radiation therapy for treatment of nasopharyngeal cancer on wound healing following extractions: incidence of complications and risk factors.

This is a prospective study of wound healing after extractions in patients who had radiation therapy for nasopharyngeal cancer. From 40 patients who fulfilled all the study criteria were extracted a total of 155 teeth. The demographic data were analysed, checking for factors that might affect the healing process after extraction. Wound healing was divided into three groups: normal wound healing, delayed healing and osteoradionecrosis. Logistic regression was used to analyse possible relationships. There was a low complication rate: 5.8% and 1.9% of extractions showed delayed healing and osteoradionecrosis, respectively. The age of the patient at time of extraction was the only significant factor that influenced the occurrence of delayed healing. It was observed that localized radiation absorption was considerably different from the total radiation dose. In conclusion, postradiation extractions have a low risk of complications and the results point to age as a factor that may influence wound healing.

Adult↗
PubMed2006

Survival of root filled cracked teeth in a tertiary institution.

AIM: To assess the survival rate of root filled cracked teeth over a 2-year period in a tertiary institute. METHODOLOGY: Forty-nine patients who had root canal treatment completed on their cracked teeth at the National Dental Centre (Singapore) were recalled for a 2-year review. Collected review data included presence of periodontal pocketing, sinus tract and swelling associated with the teeth. The date of extraction was noted if a tooth was missing at review. Pre-treatment data collected were number, extent and location of crack, presence of periodontal pocketing, patients' age and gender, location of cracked teeth, type of teeth and presence of terminal cracked tooth. RESULTS: Fifty teeth in 49 patients were included. The Kaplan-Meier estimate of 2-year survival rate was 85.5% (95% confidence interval: 75.5-95.5). Cracked teeth which were the terminal teeth in the dental arch (RR = 4.9, 95% CI: 1.2-2.0, P = 0.04), teeth with pre-root filling periodontal pocketing (RR = 4.9, 95% CI: 1.2-2.0, P = 0.04) and teeth with multiple cracks (RR = infinity, 95% CI: 1.9-infinity, P = 0.01) were more likely to be extracted. CONCLUSIONS: Within the limitations of this study, multiple cracks, terminal teeth and pre-root filling pocketing were significant prognostic factors for the survival of root filled cracked teeth.

Adult↗
PubMed2001

The importance of routine magnetic resonance imaging in trigeminal neuralgia diagnosis.

The aim of the study was to determine the frequency of structural lesions diagnosed on magnetic resonance imaging (MRI) in a sample of patients with trigeminal neuralgia (TN) and to compare history and clinical features between the groups with and without structural lesions. Clinical records and MRI findings of 42 consecutive patients diagnosed with TN at the National Dental Centre, Singapore, and who underwent routine MRI examinations at diagnostic workup between April 1997 and March 1999 were retrospectively studied. Of these, 6 (14.3%; 95% confidence interval, 0 to 28.8%) were diagnosed with an associated structural lesion. Mean age of the group with structural lesions was 53.3 years (standard deviation, 10.9 years) at presentation, there was female predominance (M:F = 1:2), and all (100.0%) gave a typical pain history and had unilateral involvement of a single division of the trigeminal nerve. Two patients (33.3%) had other cranial nerve abnormalities. Three patients (50.0%) had complete, 2 patients (33.3%) had partial, and 1 patient (16.7%) had poor response to medical therapy. None of these variables was statistically different from the group without structural lesions (cranial nerve abnormalities were not compared). In conclusion, the frequency of structural lesions associated with TN in our sample was relatively high. It is not possible to reliably identify high risk patients for selective MRI indication on the basis of history and clinical features. It may be prudent to consider routine MRI for all patients with TN to exclude structural lesions.

Adult↗
PubMed2000

Posterior fossa subdural hematoma due to ruptured arteriovenous malformation. Case report.

Patients with cerebellar arteriovenous malformations (AVM) commonly present to the neurosurgical department after having suffered hemorrhages. The subarachnoid space is the usual location for these often repeating episodes of bleedings. In addition, these patients can present with parenchymal hemorrhage. Acute subdural hematoma caused by a ruptured cerebellar AVM is a rare entity and is not generally recognized. The authors present a case of acute posterior fossa subdural hematoma resulting from a ruptured cerebellar AVM.

Aneurysm, Ruptured↗
PubMed2000

Odontogenic keratocyst of the maxilla presenting as periodontal abscess.

This is a case report of an odontogenic keratocyst of the maxilla initially diagnosed and treated as a periodontal abscess. The occurrence of odontogenic keratocyst in the maxilla with involvement of the antrum is relatively rare. The radiological appearance of this lesion on both conventional and panoramic radiography can be misinterpreted and emphasizes the usefulness of the computed tomography in this region.

Adult↗
PubMed2000

Cryotherapy in the management of trigeminal neuralgia: a review of the literature and report of three cases.

Trigeminal neuralgia is a unique neuropathic syndrome confined to the trigeminal system with no analog in the somatic dermatomes or the other cranial nerves. Medical treatment remains the first line of treatment with carbamezapine as the drug of choice. Surgery, central or peripheral is indicated when medical treatment fails or its side effects diminishes quality of life. No surgery offers a permanent cure. Recurrence rates are highest in the most peripheral techniques but these also have the lowest morbidity. Cryotherapy produces a reliable, prolonged and reversible nerve block with no aggravation of symptoms. It is a simple and repeatable procedure in patients who want to avoid major surgery or where it is contra-indicated.

Aged↗
PubMed1998

Reversible dementia due to dural arteriovenous fistula: a simple surgical option.

Dural AVMs can produce a wide variety of symptoms related to raised intracranial pressure, venous congestion, and cerebral ischaemia. We present a unique case of reversible dementia, due to venous hypertension. The cerebral ischaemia was caused by extensive bilateral arteriovenous malformations of the external carotid system, which drained into the superior sagittal and transverse sinuses and resulted in venous hypertension. Although partial occlusion by endovascular embolization and ligation procedures had some effect, only 'scalping and silastic implantation' gave satisfactory amelioration of symptoms.

Aged↗
PubMed1995

Chopsticks and suicide.

A case of serious suicidal attempt in a stroke patient by piercing a chopstick through the nostril, resulting in cerebral injury, is reported. The choice of the chopstick as a suicide tool is discussed in a clinical and cultural perspective. The potential of using chopsticks as an offensive weapon in suicidal patients is emphasised.

Brain Injuries↗
PubMed1994

Stability of ceftazidime and vancomycin alone and in combination in heparinized and nonheparinized peritoneal dialysis solution.

OBJECTIVE: To examine the stability of ceftazidime, vancomycin, and heparin, alone and in combination, in dialysis solution over six days at three temperatures. DESIGN: Nine 250-mL Dianeal PD-2 dextrose 1.5% bags were prepared with ceftazidime, vancomycin, and heparin alone and in combination at set concentrations of 100 micrograms/mL, 50 micrograms/mL, and 1 unit/mL, respectively. Three bags of each mixture were stored at 4, 25, and 37 degrees C. Duplicate samples for analysis were removed from each bag at the following time points: premix, 0, 12, 24, 48, 72, 96, 120, and 144 hours. MAIN OUTCOME MEASURES: Each sample was examined visually for signs of cloudiness and precipitation. Each sample was analyzed by stability-indicating HPLC assay for ceftazidime and vancomycin, with stability defined as less than 10 percent degradation of drug over time. RESULTS: No color change or precipitation was observed in any bag. Vancomycin with or without heparin was stable for 5-6 days at 4, 25, and 37 degrees C. Ceftazidime with and without heparin was stable for 6 days at 4 degrees C, 4 days at 25 degrees C, and less than 12 hours at 37 degrees C. Vancomycin plus ceftazidime with and without heparin was stable for 6 days at 4 degrees C and 25 degrees C, and 4-5 days at 37 degrees C. Ceftazidime plus vancomycin with or without heparin was stable for 6 days at 4 degrees C, 2-3 days at 25 degrees C, and 12 hours at 37 degrees C. CONCLUSIONS: Bulk preparations of ceftazidime and vancomycin, alone and in combination and with or without heparin in Dianeal PD dextrose 1.5% solution, are sufficiently stable for use up to 6 days under refrigeration or 48 hours at room temperature.

Ceftazidime↗
PubMed1992

Traumatic extradural hematoma of delayed onset is not a rarity.

During a 4.5-year period, 73 patients with traumatic extradural hematoma (EDH) were admitted to the neurosurgical unit of the same hospital and managed with surgical evacuation. Of these consecutive admissions, 22 patients with delayed EDH are reported. The incidence of this condition (30%; 22 of 73) contrasts with reports in the literature of 0 to 10%. This may be related to the availability of computed tomography and its liberal and early use in all head injuries. The overall mortality of traumatic EDH (5%; 4 of 73) was related to cases of delayed onset EDH. In addition to a high index of suspicion, early diagnosis of delayed EDH can be facilitated by liberal use of intracranial pressure monitoring and serial computed tomography.

Adult↗
PubMed1988

Intracranial olfactory neuroblastoma mimicking carcinoma: report of two cases.

Two cases of olfactory neuroblastoma which presented clinically as intracranial lesions are described. Prominent features of epithelial differentiation were present, which led to initial diagnoses of poorly differentiated carcinoma. The true nature of the lesions was only established subsequently by careful histological examination, immunohistochemistry and electron microscopy. The potential towards epithelial differentiation in such tumours was emphasized and certain new histological features were described, including a biphasic epithelial and stromal pattern, papillae formation and positive staining for cytokeratin. These two cases underline the importance of exhaustive examination of poorly differentiated epithelial-like lesions of the frontal lobes by conventional histology, immunohistochemistry and electron microscopy.

Brain Neoplasms↗
PubMed1988

Primary cerebral T-cell lymphoma: a case report.

A case of a 16-year-old boy with a rapidly progressive primary cerebral pleormorphic lymphoma of the brain is reported. Immunostaining with a panel of antibodies confirmed the T-cell lineage of the tumour. This is apparently the first documented report of primary T-cell lymphoma of the central nervous system.

Adolescent↗