Biomedical subjects

B Kwok

Publications and source records attributed to B Kwok.

11 recordsLinked to original sources

PubMed2006

Central neurocytoma in third and fourth ventricles with aqueductal involvement.

Central neurocytomas are characterized by their intraventricular locations, usually arising from the lateral ventricles and their benign clinical course. Variations in location, histology and clinical behaviour have been reported in recent years. The authors present two cases of central neurocytomas arising in the third and fourth ventricles with aqueductal involvement. The atypical features in their location and behaviour are discussed. The cases represent the extended spectrum of central neurocytomas.

Adult↗

PubMed2004

Variability in normative urine flow rates.

PURPOSE: Parameters derived from uroflowmetry are frequently used in the evaluation and reassessment of children presenting with lower urinary tract dysfunction. Since current nomograms have been constructed from 1 to 2 voids per child, variability of flow parameters is unknown. We evaluate intraindividual variability of flow parameters in children free of lower urinary tract symptoms. MATERIALS AND METHODS: Children between 4 and 16 years old (mean age 9.8) who were hospitalized but not suffering from urinary tract infection, pyelonephritis or neurological disturbance, and who had neither structural abnormality of the urinary tract nor acute pain or disorientation voided spontaneously over a flowmeter on 4 to 6 occasions. Post-void urine was estimated by ultrasound within 5 minutes of micturition to confirm complete emptying. RESULTS: A total of 98 subjects provided a mean of 4.4 traces each. Neither maximum nor average flow rate showed great intraindividual variability (maximum flow rate r >0.8, average flow rate r >0.74). Flow rates significantly correlated with flow duration, volume voided and patient age. Initial flow curves were bell-shaped in 63% of cases, staccato in 30% and intermittent in 6%. These proportions did not change with subsequent voids. There was no significant difference between genders with respect to staccato voiding, although boys demonstrated 70% of intermittent voids and were significantly older than girls. CONCLUSIONS: In normal children there is minimal variability in flow rates and the phenomenon of staccato voiding is seen approximately 30% of the time, despite no significant levels of post-void residual urine.

Adolescent↗

PubMed2000

Craniofacial resection for paranasal sinus cancers.

BACKGROUND: Combined anterior craniofacial resection (CFR) has been in use for more than 25 years. The advent of the free revascularized tissue transfer flap in l980 permitted safe resection of tumors that had spread beyond the confines of the paranasal sinuses with immediate reconstruction of the sino-orbital cranial defect. The purpose of this study was to examine the outcomes and morbidity of a management policy of primary CFR and postoperative radiotherapy for paranasal sinus cancers infiltrating the skull base over a 21-year period. METHODS: Seventy-three patients with paranasal sinus cancers were treated at the Prince of Wales Hospital between l975 and l996. All were newly diagnosed with the exception of one patient who had received radiotherapy elsewhere 5 years earlier. Only 22% were early lesions and 31% were advanced (more than six sites involved). There were 59 men and 14 women. The mean age was 57 years. All but two patients had a performance status of either 0 or 1. Orbital exenteration was performed in 31 patients. Since l980, all major defects were reconstructed with free tissue transfer flaps. RESULTS: The 5-year cancer-specific survival (CSS) for the 73 patients was 69%, which was unchanged at 10 years. Twenty two patients died from or with their index cancer. An additional 11 patients died from unrelated causes. The actuarial overall survival (OS) at 5 and 10 years was 61% and 48%, respectively. The 5-year recurrence-free rate was 59%. The CSS for the three dominant pathologic conditions were adenocarcinoma 70%, squamous cancer 51%, and olfactory neuroblastoma 84%. The difference was not significant; however, there was a significant difference in OS, with olfactory neuroblastoma having the best prognosis. Orbital involvement, radiologic evidence of skull base erosion, and involvement of the infratemporal fossa were not poor prognostic indicators. Patients with a performance status of 0 had improved OS. There was no operative mortality. CONCLUSIONS: An aggressive policy of combined CFR and postoperative radiotherapy with free-flap reconstruction for large defects gave survival results that were comparable to less-advanced lesions and superior to many other treatment alternatives. There was a high exenteration rate (42%). Squamous cancers were associated with the greatest morbidity and poorest OS.

Adult↗

PubMed1986

Preventable causes of death and disability from neurotrauma.

Preventable causes of death and disability have been studied retrospectively in a series of 1161 cases of neurotrauma occurring in New South Wales in 1977-78, and prospectively in 153 cases of neurotrauma occurring in country districts in South Australia in 1981-82. In the first study, it was found that at least 80 deaths could be attributed to preventable causes; chiefly, transfer to an inappropriate hospital and/or delay in instituting treatment. Apparent failures in initial management of shock and airway obstruction were evident in this study and also in the South Australian study, which identified major deficiencies in cardiorespiratory management in 7% of cases transferred from country areas. These studies confirm that there is a need for better training, at all levels, in the management of neurotrauma. They also provide powerful arguments for the concept of an integrated regional trauma service.

Australia↗

PubMed1986

Experience with extradural haematomas in New South Wales.

A retrospective study of 126 patients with extradural haematomas was made to determine whether their outcome could be modified by alteration of their management. Poor outcome occurred in those over 65 years of age, in motor smash victims, in those with fixed pupils, in those with major associated injuries or those comatose on hospital admission. The detection of skull fracture or of a lucid interval was not prognostically useful. A graduation in mortality according to the type of hospital was present but did not reach statistical significance. Failure to correct shock and delay in instituting definitive treatment were the major preventable factors which could be modified to improve outcome.

Adolescent↗

PubMed1986

Experience with multiple intracranial haematomas in New South Wales.

A retrospective survey of head injuries in NSW in 1977 and 1978 was conducted by the Trauma Subcommittee of the Neurosurgical Society of Australasia. This paper describes the findings for 129 patients who had more than one significant intracranial haematoma. Overall, the case fatality rate for these patients was 85%. The presence of low or fluctuating blood pressure was associated with a significantly higher mortality than in the rest of the group. Bilateral reacting pupils or an improvement in level of consciousness following decompressive surgery carried a more favourable prognosis. There was 100% fatality if surgery was not carried out or if the bleeding was not found at operation. A subset of patients who died was selected on the basis of a calculated prognostic variable, and compared with a similar subset of survivors. A higher proportion of patients who died had a delay in the provision of definitive treatment and failure to correct shock. This comparison was made on two criteria. Using the first accepted optimal treatment in 1984, nearly all cases were treated suboptimally, as might be expected. Using the second, acceptable treatment in 1977-78, it was calculated that between nine and 12 patients died with MIH in NSW in the 2 years of the survey, whose deaths might have been prevented.

Accidents, Traffic↗

PubMed1986

Experience with acute subdural haematomas in New South Wales.

A retrospective survey of head injuries in NSW in 1977 and 1978 was conducted by the Trauma Subcommittee of the Neurosurgical Society of Australasia. Two hundred and ninety patients, who were found to have acute or subacute subdural haematomas, were considered. The mortality rate was 76%, with 19% making a satisfactory recovery. Several factors were found to produce significant improvement in outcome. The availability of neurosurgical facilities at the time of admission made a significant difference. Those patients who had decompressive operations also fared better. No patient survived without operation. Shock, defined as a systolic blood pressure lower than 90 mmHg for more than 60 min was associated with significantly increased mortality. The chance of developing a significant hypotensive episode was greater if two or more other parts of the body were injured. If three other areas were injured, the mortality was 100%. A case control study suggested that some 35 (16%) of all deaths could have resulted from preventable causes, notably delay in instituting definitive treatment and/or inadequate treatment of shock.

Acute Disease↗

PubMed1986

Epidemiology and clinical outcomes of neurotrauma in New South Wales.

This study of 1161 neurotrauma patients in New South Wales hospitals was designed to examine the role of preventable causes of death and disability in cases of spinal injury, extradural, subdural and multiple intracranial haematomas in order to make recommendations for improvements in accident, emergency, ambulance and hospital services. Methods have been developed for standardizing diagnosis in different classes of hospital for the assessment of severity in terms of the patient's age, sex, physical signs, head and spine injuries and other injuries. Estimates have been made of the number of preventable deaths by a case control study of each category of neurotrauma under study.

Adolescent↗

PubMed1986

Experience with spinal injuries in New South Wales.

Two hundred and two patients with acute and severe spinal injuries were treated in various hospitals in New South Wales during 1977 and 1978. Of these, 132 (65%) were cervical, 60 (30%) thoracic, eight (4%) lumbar and two were inadequately recorded. A major concurrent injury to the head was present in every third patient, to the chest in every fourth patient, and to the limbs in every fifth patient. The outcomes of patients reported in this series make it one of the worst in the literature. Sixty-nine (34%) patients died in hospital; of the 133 survivors, only 22 (11%) have resumed work, the remainder being partially or totally disabled. It is estimated that another 302 patients died before arrival in hospital. In country areas, the time lags between accident and ambulance notification, and between notification and arrival at hospital, were uncertain in many cases, but periods in excess of 2 hours were recorded in 28 (14%). One-man ambulances or private vehicles were used in at least 43 cases (21%). After admission, 139 patients were transferred to other hospitals for definitive treatment, arriving after an average time of 22 h (median time 9 h); for such patients, the original hospital presumably served as a first aid station. A case control study suggests that preventable delay in transport, inappropriate treatment, and failure to correct shock may have been causative factors in 16 deaths in this series. Reduction of the time lag between accident and institution of definitive treatment will save lives, and may avoid some crippling neurological deficits.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents↗

PubMed1986

Experience with chronic subdural haematomas in New South Wales.

This study considered 135 cases of chronic subdural haematoma following head injury in 1977 and 1978. The majority were in the older age group and more often males. Falls were the commonest cause. Among intracranial haematomas they carry a much better prognosis. However, there was a mortality rate of 9% and delay in diagnosis was the most likely preventable factor contributing to this. Accordingly the possibility of this complication after head injury should be known to those concerned in the later hospital treatment and follow-up management especially of older patients and alcoholics. When the diagnosis has been made, the preferred surgical method of treatment is drainage through burrholes. Follow-up CT scanning should be arranged usually about 8 weeks afterwards unless there are clinical indications for an earlier examination.

Adolescent↗

PubMed1986

Logistics of early management of head and spinal injuries.

The logistics of early management have been studied in a series of 1161 patients with head and/or spinal injuries, who were admitted to hospital in NSW in 1977-78. Special attention has been given to three subgroups: 336 head injuries with records of impaired consciousness before first hospital admission, 355 head injuries later transferred because of deterioration, and 202 serious spinal injuries. It was found that in at least 18% of unconscious head injuries, and a similar percentage of spinal injuries, first aid and transport to hospital were provided by ambulances recorded to have only one trained staff member. In country areas, 41% of unconscious head injuries reached hospital after periods of time exceeding 1 h. For administrative as well as geographic reasons, more than 80% of initially unconscious head injuries and spinal injuries were first admitted to hospitals without neurosurgical and/or spinal services; the majority of cases in both groups, therefore, had to be transferred to other hospitals, often within 6 h of first admission. In the subgroup of cases transferred because of deterioration, mortality increased with distance from a neurosurgical unit. These findings are related to the concept of an integrated regional trauma service.

Ambulances↗