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Biomedical subjects

N W Knuckey

Publications and source records attributed to N W Knuckey.

At least 37 records · Page 2Linked to original sources
PubMed1993

Congenital anomaly of the second cervical vertebra predisposing to progressive cervical myelopathy. A case report.

The authors describe a previously unreported constellation of developmental anomalies of the C2 vertebra, which predisposed to the development of cervical myelopathy in a young patient. The embryology of the vertebral column is reviewed briefly, and the origin of each anomaly of the C2 vertebra is traced to one of the two early stages in development as follows: 1) the formation of the mesenchymal vertebra or 2) its induction to cartilage. This case emphasizes the importance of congenital stenosis in the development of cervical myelopathy in young patients. The outcome is favorable when it is treated aggressively.

Cervical Vertebrae↗
PubMed1992

Intramedullary epidermoid associated with an intramedullary spinal abscess secondary to a dermal sinus.

Intramedullary spinal abscesses are rare and potentially devastating lesions. A heightened clinical awareness of patients at risk is essential for an early diagnosis and intervention to improve the prognosis of these patients. The first case of spinal abscess was described in 1830, and only 63 cases have been reported subsequently. Intraspinal epidermoids also are unusual lesions. These tumors were reported first in 1829 and represent less than 1% of all intraspinal tumors. We present a case of a 2-year-old girl who had rapidly progressive paraplegia with urinary and bowel retention and was found to have an intramedullary epidermoid and an intramedullary abscess as a result of a dermal sinus. The association of an intramedullary abscess and epidermoid tumor, two rare lesions, has not been reported previously. We also review the literature related to both intramedullary epidermoids and intramedullary abscesses of the spinal cord. Advances in sectional imaging as described should help lead to an early and safe diagnosis of these rare but often debilitating lesions. This case illustrates the importance of a complete neurological assessment of all patients with a congenital dermal sinus because of the potential for intradural extension and the frequent association with other dysraphic abnormalities. Prophylactic surgery is indicated in many cases to prevent dangerous and recurrent infections of the central nervous system.

Abscess↗
PubMed1992

Thrombosis of difficult intracranial aneurysms by the endovascular placement of platinum-Dacron microcoils.

Patients with symptomatic aneurysms that are not excluded from the cerebral circulation have a poor prognosis. Standard treatment is surgical exploration with direct clipping of the aneurysm. Because of their large size or relationship to the base of the skull, some aneurysms may not be suitable for direct surgical clipping and may require alternative treatment modalities. A prospective clinical and radiological study of seven patients treated with the endovascular placement of platinum-Dacron microcoils to exclude the aneurysm from the cerebral circulation is reported. The seven patients ranged in age from 37 to 63 years; four were women. At completion of the endovascular procedure, total occlusion of the aneurysm with preservation of the parent artery had been achieved in four patients and 90% occlusion of the aneurysm in two. In the seventh patient, occlusion of the internal carotid artery resulted in the patient's death. At the 6-month follow-up review, both patients with an aneurysm less than 20 mm in size had persistent aneurysm thrombosis; however, the two patients with giant aneurysms had partial recanalization. Both required repeat thrombosis of their aneurysm with the placement of additional microcoils, one at 6 weeks and one at 6 months. These two patients have persistent aneurysm thrombosis at 12 months following their second procedure. The patient mortality rate for this study was 14%, while the procedure mortality/morbidity rate was 9%. It is concluded that thrombotic aneurysm therapy of difficult aneurysms is a safe procedure and will have a place in the treatment of selected aneurysms.

Adult↗
PubMed1992

Early single-stage repair of complex craniofacial trauma.

The traditional surgical management of complex craniofacial injuries is performed in three stages: immediate craniotomy, orbitofacial repair in 7 to 10 days, and cranioplasty delayed 6 to 12 months because of the perceived risks of infection and prolonged anesthesia in the head-injured patient. Cosmetic considerations have always played a secondary role; however, there are reports that suggest that bone fragments and grafts can be safely placed even in contaminated wounds. In addition, advances in neuroanesthetic technique allow for prolonged administration of anesthesia without untoward effects on the patient. The purpose of this prospective study was to determine if early single-stage repair of complex craniofacial injuries could be accomplished with acceptable morbidity and mortality. In this study, 13 patients (9 men, 4 women) ranging in age from 3 to 53 years, with Glascow Coma Scale scores of 10 to 15, all had a combined single-stage repair of their complex craniofacial injuries within 24 hours of their trauma. After initial assessment and resuscitation, all patients were evaluated with computerized tomography of the face and head before surgery. Bicoronal skin flaps were used for maximum exposure for frontal sinus exenteration as well as dural repair, cortical debridement, and calvarial reconstruction. Dural grafts were necessary in 12 of 13 patients (92%), and supplementary bone grafting was required in 9 of 13 patients (69%), of which 3 of the 9 (33%) had iliac bone grafts, where split calvarial grafts were used in the other 6 of 9 (67%). No artificial cranioplasty material was used.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Cisterna magna microdialysis of 22Na to evaluate ion transport and cerebrospinal fluid dynamics.

Microdialysis is used in vivo for measuring compounds in brain interstitial fluid. The authors describe another application of this technique to the central nervous system, namely microprobe dialysis in the cisterna magna to study the dynamics of ion transport and cerebrospinal fluid (CSF) formation in the rat. The choroid plexus is the major source of CSF, which is produced by active transport of Na from blood into the cerebral ventricles. Formation of CSF is directly proportional to the blood-to-CSF transport of Na. By injecting 22Na into the systemic circulation and quantifying its movement into CSF by microdialysis, one can reliably estimate alterations in the rate of CSF formation. The sensitivity of this system was determined by administering acetazolamide, a standard inhibitor of CSF production. Because acetazolamide is known to decrease CSF formation by 40% to 50%, the cisternal microdialysis system in animals treated with this drug should detect a corresponding decrease in the amount of 22Na dialyzed. This hypothesis is supported by the 22Na uptake curves for control versus treated animals: that is, by the acetazolamide-induced average diminution of about 45% in both the rate and extent of tracer accession to dialysate. Bumetanide, a loop diuretic, reduced by 30% the 22Na entry into dialysate. Microprobe dialysis of fluid in the cisterna magna is thus a minimally invasive and economical method for evaluating effects of drugs and hormones on the choroid plexus-CSF system.

Acetazolamide↗
PubMed1991

Traumatic subarachnoid-pleural fistula in a child. A case report.

A seven-year-old girl sustained a gunshot wound to the chest and spine. Evaluation of a persistent pleural effusion demonstrated a subarachnoid-pleural fistula. Surgical closure of the dural defect resulted in resolution of the fistula. Traumatic subarachnoid-pleural fistulae are rare. The diagnosis is reached by an awareness of fistula formation from penetrating or blunt trauma to the chest.

Child↗
PubMed1989

Importance of the redox state in vasoconstriction induced by adrenaline and serotonin.

The actin myosin system and the redox state have been implicated in a number of cellular functions and in many pathological conditions. To study the predictions of a new redox theory of actin-myosin interaction we examined the relationship between the redox state and vasoconstriction of rat aorta and dog basilar artery by adrenaline and serotonin. The results show that the contraction induced by these physiological agents can be inhibited and reversed by reducing agents.

Actomyosin↗
PubMed1989

Intracranial and spinal meningiomas in patients with breast carcinoma: case reports.

Breast carcinoma has a high predisposition to metastasize to the brain parenchyma or spinal epidural space with development of progressive neurological symptoms and signs and frequently death of the patient. We report 8 patients with known breast cancer who developed neurological symptoms attributable to an intracranial meningioma and 1 patient who developed spinal cord dysfunction resulting from a thoracic meningioma. The removal of the meningiomas resulted in return of normal neurological function in all patients. At follow-up, all our patients are alive without evidence of meningioma or breast carcinoma recurrence, except 1 patient who died of a metastatic malignant melanoma. This clinical association requires repeated emphasis because of the potential benefit in management of patients with suspected metastatic disease. We have reviewed and summarized the reported literature and added our 8 cases. The mean age of presentation before the second tumor was 6 years. Breast carcinoma was diagnosed first in 85% of cases. The clinical symptoms of the meningiomas were focal neurological signs in 50% of the patients, raised intracranial pressure in 40%, and a seizure in 10%.

Adult↗
PubMed1989

The management of "asymptomatic" epidural hematomas. A prospective study.

Standard neurosurgical management mandates prompt evacuation of all epidural hematomas to obtain a low incidence of mortality and morbidity. This dogma has recently been challenged. A number of authors have suggested that in selected cases small and moderate epidural hematomas may be managed conservatively with a normal outcome and without risk to the patient. The goal of this study was to define the clinical parameters that may aide in the management of patients with small epidural hematomas who were clinically asymptomatic at initial presentation because there was no clinical evidence of raised intracranial pressure or focal compression. A prospective study was conducted of 22 patients (17 males and five females) aged from 1 to 71 years, who had a small epidural hematoma diagnosed within 24 hours of trauma and were managed expectantly. Of these, 32% subsequently required evacuation of the epidural hematoma 1 to 10 days after the initial trauma. Analysis of the patients revealed that age, sex, Glasgow Coma Scale score, and initial size of the hematoma are not risk factors for deterioration. However, deterioration was seen in 55% of patients with a skull fracture transversing a meningeal artery, vein, or major sinus, and in 43% of those undergoing computerized tomography (CT) within 6 hours of trauma. In contrast, only 13% of patients in whom the diagnosis of a small epidural hematoma was delayed over 6 hours subsequently required evacuation of the epidural collection. Of patients with both risk factors, 71% required evacuation of the epidural hematoma. None of the patients suffered neurological sequelae attributable to this management protocol. It was concluded that patients with a small epidural hematoma, a fracture overlaying a major vessel or major sinus, and/or who are diagnosed less than 6 hours after trauma are at risk of subsequent deterioration and may require evacuation. Conversely, patients without these risk factors may be managed conservatively with repeat CT and careful neurological observation, because of the low risk of delayed deterioration.

Adolescent↗
PubMed1988

Distal anterior choroidal artery aneurysm: intraoperative localization and treatment.

Distal anterior choroidal artery aneurysms with intraventricular hemorrhage are rare and difficult to treat. We report the case of a 46-year-old woman with a left distal anterior choroidal artery aneurysm presenting as a typical subarachnoid hemorrhage from which she had no focal neurological signs. Because the aneurysm was located within the dominant deep temporal lobe, we used intraoperative computed tomography to guide a probe to the aneurysm to allow minimal dissection. This is the first report of a successfully treated distal anterior choroidal artery aneurysm. Reports of this unusual aneurysm and methods of approaching deep temporal lesions are reviewed.

Female↗
PubMed1985

Early cerebral blood flow and computerized tomography in predicting ischemia after cerebral aneurysm rupture.

Cerebral blood flow (CBF) was measured during the 1st week of subarachnoid hemorrhage in 46 patients who were in a good clinical grade and had a proven ruptured intracranial aneurysm. The mean initial CBF in patients who developed cerebral ischemia was 42 ml/min-1/100 gm brain-1, which was significantly lower than in patients who did not develop cerebral ischemia (49 ml/min-1/100 gm brain-1). This reduced CBF was not secondary to raised intracranial pressure or angiographic spasm. Patients with a reduced CBF (less than 50 ml/min-1/100 gm brain-1) and diffuse subarachnoid blood on computerized tomography had a very high incidence (78%) of cerebral ischemia, despite a good clinical grade at the time of measurement. Serial CBF measurements are of value in monitoring the evolution of cerebral vasospasm.

Cerebrovascular Circulation↗
PubMed1983

Computerized axial tomography in clumsy children with developmental apraxia and agnosia.

Fifty-one children who were clumsy because of perceptual disabilities and/or defects of motor organization were surveyed with computerized axial tomographic (CT) head scanning and compared to 33 controls by using both linear measurements and visual appraisal of the scans. Thirty-nine percent of these so-called clumsy children described as having developmental apraxia and agnosia, compared to 9% of the controls, were either abnormal or normal variants. These presumed abnormalities included ventricular dilatation, peripheral atrophy and parenchymal lesions. The Evans Ratio and Intercaudate Distance in the clumsy children were not significantly different from the controls, but the Ventricular Area Index was found to be very significantly different in the two groups.

Agnosia↗
PubMed1983

Clumsy children: a prognostic study.

Twenty-four clumsy children of whom 13 had matched controls were reappraised eight years after their original assessment. The findings indicate that developmental clumsiness generally has a favourable prognosis. Mild and moderate degrees of clumsiness improved to normality, but severe degrees of clumsiness had a less favourable outcome only in regard to motor proficiencies. Clumsiness seemed not to have bearing, either on social class or on the subsequent pursuit of sporting activities. Although there was a lower level of academic achievement in the clumsy children, who also chose careers which were less manually exacting, these observations did not reach statistical significance. Maturational lag might be the aetiology in mild developmental clumsiness, whereas structural lesions involving the cerebral cortex may be present in more severely afflicted children. These findings should be considered when counseling clumsy children, both academically and vocationally.

Adult↗
PubMed1983

Subarachnoid haemorrhage in children caused by cerebral tumour.

Subarachnoid haemorrhage in children is uncommon. In a review of 110 children with an intracranial tumour over a 20 year period there were four patients (3.6%) who presented with the typical features of a subarachnoid haemorrhage. During the same period of time there were 15 children who presented with subarachnoid haemorrhage of which 26% were secondary to a cerebral tumour. This study suggests that cerebral tumour is a common cause of subarachnoid haemorrhage in children.

Age Factors↗
PubMed1982

Medical management of patients following a ruptured cerebral aneurysm, with epsilon-aminocaproic acid, kanamycin, and reserpine.

Patients suffering from a subarachnoid hemorrhage who were admitted to the Neurosurgical Unit of the Royal Perth Hospital during the period 1971 to 1979 were assessed with regard to the effectiveness of preoperative treatment with epsilon-aminocaproic acid, kanamycin, and reserpine. Forty-two patients who were treated with epsilon-aminocaproic acid had a rebleed rate of 2.3% compared to 1 9.7% rebleed rate in appropriately selected controls. Patients treated with kanamycin and reserpine had a preoperative cerebral vasospasm rate of 32% compared to a 26% rate in controls; however, kanamycin and reserpine were found useful for decreasing the postoperative complications of cerebral vasospasm.

Aminocaproates↗
PubMed1980

Early computerized tomographic scan and neurological assessment in subarachnoid hemorrhage.

The grade of cerebral function on admission, the clinical outcome and the initial computerized tomographic (CT) scan of 52 patients with subarachnoid haemorrhage have been reviewed. The presence of widespread haemorrhage, hydrocephalus, haematoma and ischaemia on the initial CT scan is associated with poor neurological outcome in this series, irrespective to the initial neurological grading.

Brain↗