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Biomedical subjects

A David Mendelow

Publications and source records attributed to A David Mendelow.

8 recordsLinked to original sources
PubMed2003

Predicting clinical ischaemia during awake carotid endarterectomy: use of the SJVO2 probe as a guide to selective shunting.

Stroke is a major cause of disability within the western world. About 20% of strokes are a consequence of atheromatous narrowing of the origin of the internal carotid artery. Carotid endarterectomy has been shown to be an effective treatment for those with symptomatic and severe stenosis, provided the risk of death and peri-operative stroke is less than 7%. The aim of this study was to investigate the clinical value of jugular venous oxygen saturation (SJVO2) monitoring in identifying patients who develop cerebral ischaemia whilst undergoing an awake carotid endarterectomy by comparison with a simple neurological assessment. Each patient underwent a standard awake carotid endarterectomy. Peri-operatively a SJVO2 catheter was inserted, and the jugular oxygen saturation was correlated with the presence or absence of cerebral ischaemia. Data from 34 patients were analysed using time-series plots and by calculating a receiver operator characteristic (ROC) curve. The optimal sensitivity and specificity for this technique were found to be 1.0 and 0.8, respectively, when a 25% change in SJVO2 was used as a threshold. Although a small observational study, we have shown that percentage change in SJVO2 correlates well with the development of clinically apparent cerebral ischaemia. This technique may improve the safety of carotid endarterectomy under general anaesthesia when used with other more established monitoring methods.

Awareness↗
PubMed2003

Aneurysmal subarachnoid hemorrhage in young adults.

OBJECT: The authors reviewed the management protocols for young adults who presented with subarachnoid hemorrhage (SAH) at the Regional Neurosurgery Unit in Newcastle during a study period of 9 years. Aneurysmal SAH is uncommon in the age group selected (18-39 years) and, therefore, the performance of these patients has not been extensively reported in the literature. The authors also evaluated the good-grade rebleed rate (an index of management efficiency) in this cohort of patients. METHODS: The Newcastle neurosurgical unit serves a population of close to 3 million people, and an average of 180 patients with SAH are seen each year. The majority of patients are transferred from other hospitals in the region. This study includes patients admitted between January 1990 and December 1998. A total of 1,609 patients were admitted during this period, of whom 295 (18.4%) between the ages of 18 and 39 years constituted the study population of young adults. Two hundred ninety-five young adults presented with SAH; 181 (61.4%) were women and 114 (38.6%) were men, a ratio of 3:2. Of 246 patients in whom this value was recorded, 15 (6.1%) presented with a history of hypertension, and there was an association between hypertension and the occurrence of multiple aneurysms (Fisher two-tailed exact test, p = 0.008). Thirty-five patients (11.9%) presented with a hematoma on computerized tomography scans; of these, 20 (57%) were women and 15 were men. In six patients the lesion had rebled before treatment. The good-grade rebleed rate was three (1.7%) of 178. The overall favorable outcome rate was 83.8% (Glasgow Outcome Scale [GOS] 4 and 5) and unfavorable outcome occurred in 16.2% (GOS 1-3), with a total of 40 deaths in this group (13%). Age had no influence on outcome in young adults. Comparing the outcome at discharge with the follow-up evaluation at 6 months revealed that patients in the moderate and severe disability groups continued to improve and many achieved good recovery. CONCLUSIONS: In this report the authors detail the outcome of a large number of young adults with SAH. The incidence of SAH was higher in the female population, although the ratio was not as high as previously reported. The authors have also demonstrated a progressive increase in the incidence of aneurysmal SAH with age, even in young adults. Hypertension but not age influenced the occurrence of multiple aneurysms. The good-grade rebleed rate is low, although it is not zero. Generally, a satisfactory outcome was obtained and significant continuing improvements were noted between discharge and follow-up evaluation. This reflects the power of recovery in young adults. These are people whose economic productivity and fertility are at peak levels and therefore the financial and social burden occasioned by less-than-perfect outcomes is large.

Adolescent↗
PubMed2002

Computed tomography angiography for the evaluation of carotid atherosclerotic plaque: correlation with histopathology of endarterectomy specimens.

BACKGROUND AND PURPOSE: The goal of this study was to determine the efficacy of CT angiography for the characterization of plaque morphology and composition in carotid atherosclerotic disease. METHODS: Fifty-five patients undergoing carotid endarterectomy were imaged preoperatively with single-slice spiral CT angiography. One hundred sixty-five endarterectomy sections were examined histologically at selected levels through the distal common and proximal internal carotid arteries. Plaque density was measured (in Hounsfield units) on axial CT sections, and the presence or absence of ulceration was noted. These observations were compared with the histological findings at corresponding levels. Data were analyzed with 2-sample t tests and 1-way analysis of variance (ANOVA). RESULTS: ANOVA testing showed a statistically significant decrease in CT attenuation values with increasing plaque lipid but with a very high standard deviation of values. No other histological factor showed a statistically significant link with CT attenuation. Plaque ulceration was detected by CT with a sensitivity of 60% and a specificity of 74%. CONCLUSIONS: Analysis of plaque attenuation with single-slice spiral CT does not give useful information concerning plaque composition. The predictive value of CT for the detection of plaque ulceration was moderate. Single-slice CT angiography is insufficiently robust to be a useful tool for the characterization of carotid plaque composition and morphology.

Analysis of Variance↗
PubMed2002

Co-existing cholesteatoma and vestibular schwannoma.

A 69-year-old man presented with a cholesteatoma in the right mastoid process and a vestibular schwannoma at the left internal acoustic meatus. Cholesteatoma co-existing with a vestibular schwannoma has not been documented previously in the contemporary literature. The clinical dilemma in the management of his progressive bilateral hearing loss is discussed. He presented with dizziness and bilateral hearing loss worse on the right side. Pressure over the mastoid process elicited vertigo and nystagmus. He had no history of previous operation or infection in the ear canal. Audiograms confirmed high-tone hearing loss. Radiological investigations revealed a symptomatic cholesteatoma on the right side and an incidental vestibular schwannoma on the left. We have elected to manage both lesions conservatively. Bilateral cholesteatoma and bilateral vestibular schwannomas have been previously reported. Co-existing lesions, as in our patient have, however, not been reported previously. The management options of his hearing loss are discussed.

Aged↗
PubMed2002

Comparative study of traumatic and spontaneous intracerebral hemorrhage.

OBJECT: Spontaneous intracerebral hemorrhage (SICH) and traumatic intracerebral hemorrhage (TICH) are common disorders. The authors planned to study how these two types of hemorrhage behave pathologically and clinically to gain further insight into their causes, pathogeneses, indications for surgical intervention, and prognoses. METHODS: Prospectively filled databases of demographic, clinical, radiological, and outcome details have been maintained for all patients admitted to the Regional Neurosciences Centre with head injury since 1987 and with SICH since 1993. Of the 5686 patients whose case information was included in the head-injury database, 90 were found to suffer from an isolated intracerebral hemorrhage (ICH) as the only major abnormality observed on computerized tomography scans (subdural and extradural hematomas were excluded). Case details on these 90 patients and the 440 patients from the SICH database were extracted and analyzed using a statistical software program. The median age of patients with TICH was lower than the median age of patients with SICH (51 years compared with 65 years, respectively), but it was much higher than the median age of the entire head-injury group (21 years). Among patients younger than 45 years of age, 0.8% of patients who experienced trauma suffered from an ICH compared with 4.3% of patients older than 45 years of age. Irrespective of intervention, much better outcomes were achieved by patients with TICH compared with those with SICH (67% favorable outcomes compared with 24% in patients with SICH). Following trauma, there was no significant relationship between the severity of injury and the development of ICH. At presentation the median Glasgow Coma Scale (GCS) score for both groups was 13. Younger age and higher GCS score at presentation were strongly related to a favorable outcome for both types of hemorrhage. There was no significant difference in patient age, presenting GCS score, or outcomes of patients who underwent surgery compared with those who did not for either type of hemorrhage. No conclusions can be drawn about the efficacy of surgery from such observational studies. CONCLUSIONS: On the basis of these data the authors suggest that TICH and SICH have different features: TICH affects a slightly younger age group and carries a much better prognosis compared with SICH. In addition, indications for surgical intervention are not well defined for either type of hemorrhage. Practice is subjective and inconsistent. The International Surgical Trial in Intracerebral Haemorrhage may resolve the dilemma for SICH. A similar trial in which surgery is compared with conservative management should be considered for cases of TICH.

Adult↗
PubMed2002

Reversible ischemia around intracerebral hemorrhage: a single-photon emission computerized tomography study.

OBJECT: A zone of perilesional ischemia has been demonstrated around intracerebral hemorrhage (ICH) in numerous experimental models and in human studies. There is potential for perfusion recovery in the zone of perilesional oligemia around ICH. The authors sought to demonstrate, quantify, and study the chronological evolution of perilesional ischemic change in ICH in humans by measuring cerebral blood flow. METHODS: Eleven patients with spontaneous supratentorial ICH underwent two technetium-99m hexamethylpropyleneamine oxime single-photon emission computerized tomography (SPECT) scanning, one in the acute stage (within days of ictus) and the other in the late stage (6-9 months postictus). All patients in this study were treated nonsurgically. Methods of SPECT data analysis based on count differences in regions of interest can be difficult to apply to images with large space-occupying lesions such as ICH, because of the distortion of intracranial anatomy, midline shift, and alterations in the three-dimensional (3D) characteristics of the lesion over time (that is, absorption of the hematoma on the later studies). The authors used the following method: the late and early images were registered and aligned to a common 3D orientation and were normalized to maximal counts. The late images were then compared voxel by voxel with the early ones. The region-growing algorithm was used to discern the difference between the two images, outlining voxels in the perihematoma region, with a signal improvement of at least 15% on the late image. Discrete brain regions around the hematoma with at least a 15% improvement in radiotracer uptake (and hence perfusion) in the late images were observed in all cases. The mean volume of brain with a greater than 15% improvement in perfusion between the two studies was 34.8 cm3 (range 7.2-71.3 cm3). These volumes represent regions of the brain that were poorly perfused in the initial studies. This may represent a zone of reversible perilesional oligemia (penumbra) in ICH in humans. CONCLUSIONS: This is the first study in which it is documented that some of the perilesional hypoperfused tissue around human ICH regains its perfusion in the long term, leading the authors to suggest that there may be a penumbra in human ICH. Medical or surgical therapeutic interventions could increase the volume of perilesional brain that recovers after the initial insult. The results of this study therefore support the concept that intervention in ICH has the potential to reduce the ultimate neurological deficit and improve outcome.

Adult↗
PubMed2002

Subarachnoid haemorrhage.

Aneurysmal SAH is a devastating condition arising suddenly and usually without warning. The best outcomes may be facilitated by prompt recognition/suspicion and immediate referral to the neurosurgical unit. Many contentious issues surround this subject and the ISAT trial should resolve many of these. Modern developments alongside evidence-based practice should hopefully optimise results.

Algorithms↗