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W F Harkness

Publications and source records attributed to W F Harkness.

35 records · Page 2Linked to original sources
PubMed1996

Activation of the electrocorticogram by propofol during surgery for epilepsy.

Propofol is used widely during general anaesthesia but there has been concern that it may be implicated in provoking seizure activity. We have investigated the effects of low-dose propofol on the electrocorticogram of anaesthetized patients undergoing surgery for medically intractable epilepsy. During continuous peroperative recording of the electrocorticogram, propofol was administered in 25 mg increments until burst suppression occurred. Activation of the electrocorticogram occurred in 17 of 20 patients. There was an increase in mean spike frequency in 16, extension of spike distribution in 15 and polyphasia in 13 patients. The mean dose of propofol required to cause burst suppression was 88.2 (range 25-175) mg. We conclude that at low doses, propofol caused activation of the electrocorticogram in epileptic patients but at higher doses burst suppression was induced.

Adolescent↗
PubMed1996

The effectiveness of papilledema as an indicator of raised intracranial pressure in children with craniosynostosis.

Craniosynostosis management partially depends on the detection and treatment of elevated intracranial pressure (ICP). Examination for papilledema is considered to be the most reliable screening method for identifying raised ICP, but its effectiveness has not been defined. One hundred and twenty-two children with craniosynostosis who underwent funduscopic examinations and then Camino ICP monitoring were studied. All eye examinations were performed by an ophthalmologist after pharmacological pupillary dilation. Fifteen patients (12%) had papilledema. Subsequent ICP monitoring showed that the median ICP was 12.7 mm Hg, with 41 patients (34%) having elevated ICPs (> 15 mm Hg). Those with papilledema had higher ICPs (17.5 +/- 3.2 versus 12.7 +/- 5.5 mm Hg), were older (5.9 +/- 4.7 versus 1.9 +/- 2.6 years), and were more likely to have craniofacial syndromes (73 versus 41%) than those without papilledema (P < 0.05). Patients with both elevated ICPs and papilledema were older (5.9 +/- 4.7 versus 1.6 +/- 1.4 years) and more likely to have multiple-suture synostosis (92 versus 61%) than those with elevated ICPs and no papilledema (P < 0.05). The presence of papilledema was a specific (98%) indicator of raised ICP, but its sensitivity was age-dependent. It was 100% sensitive in children older than 8 years, but it indicated elevated ICP in only 22% of younger patients. These results suggest that ICP monitoring to document elevated ICP is unnecessary in children older than 8 years who have detailed ophthalmological examinations. In the younger child, the presence of papilledema reliably indicates elevated ICP but its absence does not rule out elevated ICP; formal ICP measurement has a greater role in detecting elevated ICP in these patients.

Adolescent↗
PubMed1996

The beaten copper cranium: a correlation between intracranial pressure, cranial radiographs, and computed tomographic scans in children with craniosynostosis.

OBJECTIVE: The beaten copper appearance of the cranium, as well as other cranial radiographic and computed tomographic findings in children with craniosynostosis, is often interpreted by clinicians as evidence of elevated intracranial pressure (ICP). However, a correlation between radiological findings and ICP measurements has not been previously demonstrated, and their usefulness in detecting elevated ICP has not been defined. METHODS: To address those issues, 123 children with craniosynostosis who had cranial radiographs and ICP monitoring were studied. To assess the specificity of certain radiological findings to patients with craniosynostosis, cranial radiographs of patients with craniosynostosis were compared to those of age- and sex-matched controls. In patients with craniosynostosis, findings on cranial radiographs were compared to computed tomographic scans of the brain. Radiographic findings were then correlated with ICP measurements obtained while the patient was sleeping, which was measured using a Camino fiberoptic ICP monitor (Camino Laboratories, San Diego, CA). All radiographs were independently analyzed by two radiologists who were blinded to clinical and ICP data. RESULTS: A diffuse beaten copper pattern, erosion of the dorsum sellar, and suture diastasis were seen more commonly in patients with craniosynostosis than in controls (P < 0.05), but the presence of the beaten copper pattern was no more common in children with craniosynostosis. ICP was greater when a diffuse beaten copper pattern, dorsum sellar erosion, suture diastasis, or narrowing of basal cisterns was present (P < 0.05). CONCLUSION: Although this study demonstrates that some cranial radiographic and computed tomographic findings do correlate with elevated ICP, the sensitivity of radiological methods for detecting elevated ICP is universally low and they are not recommended to screen for elevated ICP in children with craniosynostosis.

Child↗
PubMed1996

Use of intracranial pressure monitoring in the management of childhood hydrocephalus and shunt-related problems.

Although the clinical and radiological diagnosis of hydrocephalus in children is usually straightforward, there exists a minority of patients in whom the decision to shunt can be extremely difficult. Similarly, although the diagnosis of shunt malfunction usually presents little difficulty in the context of an acute blockage, a child can present with a confusing and unpredictable constellation of symptoms that might be caused by conditions separate from shunt malfunction. Continuous intraparenchymal intracranial pressure (ICP) monitoring was used to assess 41 patients with hydrocephalus, either as part of the initial diagnostic evaluation of ventriculomegaly (18 patients) or in the assessment of presumed shunt malfunction (23 patients). In 9 of 18 patients with ventriculomegaly, the ICP was within normal limits and surgical insertion of shunts was avoided. Of the 23 patients being assessed for shunt malfunction, the change in ICP profile indicated a siphoning or overdrainage process in 13. In no patient was there significant attendant morbidity, and the process was well tolerated and simple to perform. Clinical and radiological criteria alone can afford insufficient information in the initial evaluation and the subsequent management of the child with hydrocephalus. ICP monitoring provides a safe means of investigating such patients and provides valuable information upon which to base surgical management.

Adolescent↗
PubMed1995

The use of autologous skull bone grafts for posterior fusion of the upper cervical spine in children.

STUDY DESIGN: Traditionally bone grafts used in posterior cervical fusion have been harvested from the iliac crest, rib, tibia, or fibula. Their use is not without significant morbidity, and it is often difficult to harvest suitable quantities of good quality bone in children. We have used autologous calvarial bone secured by sublaminar wires in seven patients with congenital spinal anomalies to achieve craniocervical stabilization and fusion. OBJECTIVES: To detail our experiences with this new method of harvesting autologous bone grafts from the patient's skull for occipitocervical fusion in a pediatric practice. SUMMARY OF BACKGROUND DATA: Calvarial bone has been used extensively in craniofacial reconstructive work with good long-term results and with no significant bone resorption. The use of membranous bone is supported by several basic science studies reported in the plastic surgery literature that claim a superiority over endochondral bone regarding fusion. In the present study, autologous calvarial bone has been used in the treatment of seven cases of congenital upper cervical spine instability associated with neurologic deficit. This method circumvents many of the problems attached to the use of traditional donor sites and provides good quality bone in large quantity that can be specifically tailored to match the contours of the craniocervical junction. METHOD: We used autologous calvarial bone secured by sublaminar wires in seven children with congenital spinal anomalies to achieve craniocervical stabilization and fusion. The ensuing calvarial defect was repaired using split-thickness parietal bone with the bone graft, which was ultimately used for the cervical fusion and acted as a template to obtain a mirror image and exact match to achieve good cosmetic results. The patients were immobilized after surgery in a halo orthosis for 3 months. RESULTS: Satisfactory results (100% fusion) were achieved in all seven cases with no attendant morbidity related to the method of graft procurement. CONCLUSIONS: We recommend this technique as a safe and effective alternative to the more traditional means of graft procurement previously used in cases of craniocervical instability in children.

Adolescent↗
PubMed1995

Intracranial ependymomas in childhood: a report of 24 cases followed for 5 years.

The management and outcome of 24 patients with intracranial ependymomas admitted to our institution between January 1979 and May 1988 have been analysed. Four patients out of the ten with infratentorial ependymomas who underwent a visible total resection were alive and free of disease at 5 years, whereas all those who had had an incomplete resection were dead. The prognosis in the supratentorial group was worse; only one patient out of seven was alive and free of disease at 5 years. Nine patients (six infratentorial and three supratentorial ependymomas) were investigated with myelography for occult spinal metastases, and apart from one who had a direct extension of an infratentorial tumour into the upper cervical spine, none had detectable metastases. Eight patients with infratentorial tumours underwent a ventriculo-peritoneal shunt insertion, and in three of them this followed a visible total resection of the tumour. Comparison of our results with those from other series suggests that any improvement in outlook is related primarily to an increased number of children surviving their initial surgical treatment, rather than to better methods of postoperative tumour control.

Cerebral Ventricle Neoplasms↗
PubMed1995

Stereotactically-guided craniotomy for cavernous angiomas presenting wit epilepsy.

With the wider availability of magnetic resonance imaging cavernous malformations are being recognised with increasing frequency in those patients presenting with intractable epilepsy. Surgical resection is the treatment of choice. However, because these lesions are usually small and may be located in eloquent areas stereotactic resection should be considered. Stereotactically-guided resection of pathologically verified cavernous angiograms was performed in 10 patients in this series presenting with epilepsy (8 males, 2 females, mean age 32 years). Eight patients presented with medically intractable epilepsy (5 complex partial seizures, 3 grand mal seizures). Of the remaining patients one experienced multiple episodes of haemorrhage and the other headaches (with a non-diagnostic scan) both in association with epilepsy. Pre-operative localisation of the motor strip was determined in one case by functional MRI. Following resection of these lesions all patients experienced improved seizure control with a mean follow-up period of 22 months. The mean postoperative hospital stay was 5.1 days with no surgical complications recorded. We conclude that stereotactically-guided resection offers significant advantages in the management of cavernous malformations. Surgical indications for operative resection would include medically refractory epilepsy, repeated haemorrhage and those cases where there is diagnostic uncertainty.

Adolescent↗
PubMed1995

Air embolism during awake craniotomy.

A case of venous air embolism during awake craniotomy is described. Chest pain and electrocardiographic changes were the major presenting features. Capnography detected a decrease in end-tidal carbon dioxide and demonstrates its use as an aid in the diagnosis of air embolism in the awake patient. Following this episode persistent hypoxaemia developed secondary to acute pulmonary oedema and a pleural effusion.

Adult↗
PubMed1995

Accurate placement of the atrial catheter in ventriculoatrial shunts. Technical note.

A combined radiological and surgical technique that permits identification of appropriate recipient vessels and accurate placement of the atrial catheter in ventriculoatrial shunts is described. The procedure uses readily available radiological skills and reduces operation time and morbidity related to malpositioning of the distal catheter.

Catheterization↗
PubMed1993

A specialised computer-based monitoring system for intraoperative electrocorticography.

We have developed a computer-based intraoperative ECoG monitoring system which offers the flexibility of digital recording and allows detailed review of recorded events without interrupting monitoring. In addition, a diagram showing the electrode positions on the brain can be generated on computer screen and subsequently displayed during monitoring--this allows automatic indication of the electrode positions corresponding to specific ECoG channels and can provide the surgeon with a clear visual impression of the area of spiking.

Cerebral Cortex↗
PubMed1993

Myelography in the assessment of children with medulloblastoma.

Forty-seven out of 49 patients with a histologically-proven diagnosis of medulloblastoma admitted to our institution between 1 January 1984 and 13 December 1990 were examined post-operatively using either myelography or gadolinium-enhanced magnetic resonance imaging in an attempt to detect clinically occult spinal metastatic disease. Spinal spread of the tumour was identified in nine (19%) patients. Of the 16 patients for whom a 5-year follow-up has been available 12 had no myelographic evidence of spinal disease and of these 10 (83%) remain disease-free. Of the six who have died during this period four had evidence of spinal metastases at presentation. Of all the children in the series with spinal spread identified at the time of their initial hospitalization, only one survives to date (15 months after diagnosis). The remainder had an average life expectancy of 18 months.

Cerebellar Neoplasms↗