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Biomedical subjects

N D Kitchen

Publications and source records attributed to N D Kitchen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Intracerebral haemorrhage and drug abuse in young adults.

The epidemic of abuse of the so-called 'designer drugs' amphetamine, cocaine and ecstasy--is fast replacing traditional aetiological factors as the largest cause of intracerebral haemorrhage among young adults. Traditional teaching is that these represent hypertensive haemorrhages. Recent reports, however, have indicated that these patients may harbour underlying vascular malformations. We review 13 patients with a positive history of drug abuse preceding the onset of intracerebral haemorrhage. These patients presented to the National Hospital for Neurology and Neurosurgery in central London over a 7-month period. Of the 13 patients (eight male, five female), average age 31 years (19-43) years), 10 were well enough to undergo cerebral angiography. Intracranial aneurysms were demonstrated in six patients and arteriovenous malformations in three patients. In only one of the patients was the angiogram normal. A further patient was subsequently shown to have a middle cerebral artery aneurysm at autopsy. The epidemiology, pharmacology and systemic effects of these drugs are considered. The mechanisms by which these compounds cause intracerebral complications and their influence on prognosis are discussed. The incidence of intracerebral haemorrhage (ICH), ischaemic cerebral infarctions and subarachnoid haemorrhage (SAH) following drug abuse is increasing. Contrary to historical opinion, drug-related ICH is frequently related to an underlying vascular malformation. Arteriography should be part of the evaluation of most young patients with nontraumatic ICH. A thorough history focusing on the use of illicit substances and toxicological screening of urine and serum should be part of the evaluation of any young patient with a stroke.

Adult↗
PubMed2000

Clinical utility and cost-effectiveness of interactive image-guided craniotomy: clinical comparison between conventional and image-guided meningioma surgery.

OBJECTIVE: Although interactive image guidance has been determined to be an increasingly important and reliable tool in contemporary neurosurgery, the clinical results and cost-effectiveness of the use of these systems, compared with conventional techniques, remain understudied. The aim of this study was to investigate the possible benefits of image-guided craniotomies to treat meningiomas, in terms of hospital stays, surgical complications, and, consequently, cost-effectiveness, compared with the results of standard surgery (SS). METHODS: During a 3.5-year period, 100 patients were surgically treated for meningiomas using image-guided surgery (IGS) with neuronavigation assistance and 170 were surgically treated using SS. From the consecutive series of the 100 IGS cases, it was possible to statistically match 50 (in terms of the demographic data, the location and size of the tumor, and the experience of the surgeon) with 50 SS cases. The clinical data were collected prospectively for the IGS group and retrospectively for the SS group. RESULTS: The anesthetic (operation) times were similar for the two groups, although surgical times were shorter for the IGS group (P = 0.02). Blood loss during surgery was less for the IGS group (although not statistically significantly, P > 0.05), but more SS cases required transfusions (P = 0.03). The mean intensive therapy unit stay was 1.7 days for the SS group and 1 day for the IGS group (P = 0.12); the mean hospital stays were 13.5 and 8.5 days, respectively (P = 0.017). Severe complications (permanent or requiring additional surgical procedures) were encountered in 14% of the cases in the SS group and 6% of the cases in the IGS group (P = 0.019), whereas the rates of minor complications (resolved within 30 d without further surgery) were similar (8 and 10%, respectively). The most common problems for the control group were postoperative hematomas (n = 3), which required urgent surgery in two cases; intractable postoperative swelling was treated by lobectomy in another case. In the IGS group, the two severe complications included one case of an infected bone flap and one case of a new permanent neurological deficit. The mean cost per patient was approximately 20% higher for SS than for IGS. CONCLUSION: Although this was not a randomized study, the analysis of these results strongly suggests a positive effect of neuronavigation on the complication rate and thus on intensive care unit and hospital stays, with attendant financial implications.

Adult↗
PubMed2000

Sacral neuromodulation for women with Fowler's syndrome.

Neuromodulation of the sacral nerves has been found to be an effective therapy for a variety of lower urinary tract dysfunctions. The reported success rate for the period of trial stimulation (peripheral nerve evaluation test) prior to permanent implantation of a sacral nerve stimulator is variable, but generally reported to be in the region of 30-50%. We present here the results of the peripheral nerve evaluation test in 38 patients with urinary retention. 34 of the 38 had been found to have an abnormality of their striated urethral sphincter on electromyography using a concentric needle electrode, i.e., they had the disorder which was described by Fowler and coworkers in 1988. The overall success rate in this group was 68%. We believe that our relatively high success rate is due to sacral neuromodulation working via a mechanism which involves the urethral sphincter, an abnormality which had been demonstrated in 89% of these patients. Twelve of the patients subsequently underwent permanent implantation of a sacral nerve stimulator, and all of them have experienced a return of voiding. However, in 2 patients, there is a persisting need for self-catheterization. There is, however, a high reoperation rate.

Adolescent↗
PubMed2000

Consent to surgery in a high risk specialty: a prospective audit.

A prospective audit was performed to assess how well patients were being consented for neurosurgery. Sixty patients with various neurosurgical conditions were included in the study. Audit was performed firstly by means of a questionnaire to examine the type of information given to patients, and their understanding of such information. Secondly, the patient's medical notes were reviewed to analyse any written evidence by the consenting doctor for the consenting procedure. 100% of the patients felt that they had been informed satisfactorily about the nature of their condition and the nature of the operation. 92% understood the specific risks of their proposed operation. However, only 25% were informed about the general risks of surgery and anaesthesia. Only 33% felt that they were informed fully about alternative treatment options. 97% of the patients felt that they had reached an informed decision regarding surgery. 67% of the case notes contained information on the nature and specific risks of the operation, while information on general risks of surgery and anaesthesia was documented in only 17% of the case notes. 33% of the case notes contained no information for the consenting procedure. Our audit showed that the patients had a good understanding of the nature and aim of the operation and the specific risks. Areas that require improvement are explaining the general risks of surgery and alternative treatment. For the consenting doctor, there should be more documentation in the notes, and there should be mention of the doctor's satisfaction that the patient was deemed to be competent and had made an informed decision.

Adult↗
PubMed2000

Familial cavernous hemangioma: An expanding ocular spectrum.

OBJECTIVE: To describe the clinical and genetic findings in a family with multiple cases of cavernous hemangiomas. DESIGN: Investigational clinical and genetic study in which 3 generations of a family consisting of 12 members were screened with magnetic resonance brain imaging, dilated ophthalmoscopic examination, and cutaneous survey coupled with linkage analysis to determine affected individuals and to better define manifestations of this neuro-oculo-cutaneous syndrome. RESULTS: The proband had multiple cerebral cavernous hemangiomas and a choroidal hemangioma. Her son was found to harbor a retinal cavernous hemangioma. The proband's sister manifested a cerebral cavernous hemangioma, cutaneous hemangiomas, and a presumed choroidal hemangioma; her daughter demonstrated radiological findings suggestive of a cerebral cavernous hemangioma. The father of the proband demonstrated multiple, cutaneous hemangiomas. The remaining family members were free of lesions. The 7q locus could not be excluded as harboring the causative gene. CONCLUSIONS: This family may have a dominantly inherited neuro-oculo-cutaneous condition of cavernous hemangiomas with variable expressivity. The presence of choroidal hemangiomas in this phacomatosis has not been described previously to our knowledge. CLINICAL RELEVANCE: The presence of either retinal cavernous or choroidal hemangioma should alert the physician to search for features suggestive of systemic and familial involvement; either lesion may constitute the ocular component of the neuro-oculo-cutaneous phacomatosis, sometimes referred to as cavernoma multiplex. Arch Ophthalmol. 2000;118:969-973

Adult↗
PubMed1999

Disproportion in the distribution of gray and white matter: neuropsychological correlates.

OBJECTIVE: To examine the relationship between measures of disproportion in the regional distribution of gray and white matter and preoperative neuropsychological function in temporal lobe epilepsy patients with proved hippocampal sclerosis (HS). BACKGROUND: Subtle cerebral structural disruption, not evident on routine inspection of high-resolution MRI, is associated with poor surgical outcome in patients with histologically proved HS. Preoperative global memory dysfunction is also associated with poor postoperative seizure control. The authors hypothesize that patients with HS and abnormal regional distributions of gray and white matter would show more diffuse neuropsychological deficits preoperatively than patients with isolated HS alone. METHODS: A total of 28 adults with lateralized temporal lobe epilepsy and hippocampal volume loss measured on MRI were assessed preoperatively on neuropsychological tests of general intellect and the learning and recall of both verbal and nonverbal material. Quantitative MRI analysis of the regional distribution of gray and white matter was performed. Chi-square analyses were used to examine the relation between the presence or absence of cerebral abnormalities and preoperative performance on the neuropsychological tests. RESULTS: A total of 15 of 28 patients had extrahippocampal abnormalities on quantitative MRI analysis. Thirteen patients had global memory impairment. Bilateral memory deficits were significantly associated with both the presence of cerebral abnormalities (p < 0.02) and poor postoperative seizure control (p < 0.05). CONCLUSIONS: Disproportion in the regional distribution of gray and white matter in patients with HS may form the structural basis of global memory disturbance in a distinct group of patients with temporal lobe epilepsy.

Adult↗
PubMed1999

Artefact on MRA following aneurysm clipping: an in vitro study and prospective comparison with conventional angiography.

Using both an experimental model and clinical cases, we looked at the artefact produced by Aesculap titanium-alloy aneurysm clips on MRA. Experimentally, the volume affected by artefact was 50 % less when the clip was imaged lying parallel to the main ferromagnetic field than when lying perpendicular to it. Clinically, MRA was prospectively compared with digital subtraction angiography (DSA) in nine patients who had undergone aneurysm clipping. One patient with a non-diagnostic MRA due to movement artefact was excluded. In all other cases there was an area of signal loss surrounding the clips, obscuring the immediately adjacent vessel segments. There was good demonstration of the adjacent bifurcations in five cases and the contralateral circulation was seen well in all patients. In three cases in which the adjacent bifurcations were not seen, considerable vasospasm was suggested by MRA and confirmed with DSA. In one patient an unclipped contralateral ophthalmic artery aneurysm was identified using both modalities. In this series there were no adverse events relating to clips in either static or time-varying magnetic fields.

Adult↗
PubMed1999

Measurement of changes in opioid receptor binding in vivo during trigeminal neuralgic pain using [11C] diprenorphine and positron emission tomography.

The binding of [11C]diprenorphine to mu, kappa, and delta subsites in cortical and subcortical structures was measured by positron emission tomography in vivo in six patients before and after surgical relief of trigeminal neuralgia pain. The volume of distribution of [11C]diprenorphine binding was significantly increased after thermocoagulation of the relevant trigeminal division in the following areas: prefrontal, insular, perigenual, mid-cingulate and inferior parietal cortices, basal ganglia, and thalamus bilaterally. In addition to the pain relief associated with the surgical procedure, there also was an improvement in anxiety and depression scores. In the context of other studies, these changes in binding most likely resulted from the change in the pain state. The results suggest an increased occupancy by endogenous opioid peptides during trigeminal pain but cannot exclude coexistent down-regulation of binding sites.

Aged↗
PubMed1999

Analysis of temporal lobe resections in MR images.

PURPOSE: The nature of the resection in surgery for intractable medial temporal lobe epilepsy is likely to be a principal factor determining seizure and neuropsychological outcome. However, there is no universally accepted system for describing the characteristics of individual resections to allow comparison between patients and patient groups treated at different institutions. We therefore developed a technique of volumetric analysis of temporal lobe resections. METHODS: With comparison of coregistered pre- and postoperative, volumetric magnetic resonance imaging (MRI) scans in 10 subjects, the volumes of six temporal lobe substructures were determined by manual delineation in the pre- and post-operative images for each case, allowing the extent of resection to be determined. RESULTS: The substructures and their extent of resection were measured with acceptable repeatability in each case. CONCLUSIONS: We developed a reliable method for the quantitative description of temporal lobe resections. This will be of application in determining the relation between the anatomic nature of the resection in intractable epilepsy and the seizure and neuropsychological outcome.

Amygdala↗
PubMed1999

Accuracy of true frameless stereotaxy: in vivo measurement and laboratory phantom studies. Technical note.

The authors present the results of accuracy measurements, obtained in both laboratory phantom studies and an in vivo assessment, for a technique of frameless stereotaxy. An instrument holder was developed to facilitate stereotactic guidance and enable introduction of frameless methods to traditional frame-based procedures. The accuracy of frameless stereotaxy was assessed for images acquired using 0.5-tesla or 1.5-tesla magnetic resonance (MR) imaging or 2-mm axial, 3-mm axial, or 3-mm helical computerized tomography (CT) scanning. A clinical series is reported in which biopsy samples were obtained using a frameless stereotactic procedure, and the accuracy of these procedures was assessed using postoperative MR images and image fusion. The overall mean error of phantom frameless stereotaxy was found to be 1.3 mm (standard deviation [SD] 0.6 mm). The mean error for CT-directed frameless stereotaxy was 1.1 mm (SD 0.5 mm) and that for MR image-directed procedures was 1.4 mm (SD 0.7 mm). The CT-guided frameless stereotaxy was significantly more accurate than MR image-directed stereotaxy (p = 0.0001). In addition, 2-mm axial CT-guided stereotaxy was significantly more accurate than 3-mm axial CT-guided stereotaxy (p = 0.025). In the clinical series of 21 frameless stereotactically obtained biopsies, all specimens yielded the appropriate diagnosis and no complications ensued. Early postoperative MR images were obtained in 16 of these cases and displacement of the biopsy site from the intraoperative target was determined by fusion of pre- and postoperative image data sets. The mean in vivo linear error of frameless stereotactic biopsy sampling was 2.3 mm (SD 1.9 mm). The mean in vivo Euclidean error was 4.8 mm (SD 2 mm). The implications of these accuracy measurements and of error in stereotaxy are discussed.

Adult↗
PubMed1998

Wrapping of solitary ruptured intracranial aneurysms, outcome at five years.

Previous follow up studies of patients who have had ruptured intracranial aneurysms treated by a wrapping technique have largely been in the pre-microsurgical era. Our objective was to ascertain whether wrapping aneurysms with the aid of the operating microscope provides protection against rebleeding in the short and long term. The study involved retrospective analysis of patients with ruptured aneurysms treated by wrapping over a six-year period. Twenty-nine patients were identified with wrapped aneurysms, of these 15 had wrapping of a solitary ruptured aneurysm, the remainder were excluded because of clip/wrap combination, multiple aneurysms, and unruptured aneurysms. Of the 15 patients who had a solitary ruptured aneurysm wrapped, none had rebled at one year follow up. One patient died of a myocardial infarction at 4 years, the remaining 14 patients had no episodes of rebleeding with all patients achieving Glasgow outcome scores of four or five at 5 years follow-up. Although surgical clipping of intracranial aneurysms is the definitive method of treatment, our findings suggest that wrapping of ruptured intracranial aneurysms with the aid of the operating microscope confers good protection against both early and late rebleeding in those cases considered 'unclippable'.

Adult↗
PubMed1998

Intracranial osteosarcomas: report of four cases and review of the literature.

Four cases of intracranial osteosarcoma are reported. In three cases the tumors were primary neoplasms arising from the sellar region, base of the occiput and the parieto-occipital area. One case represented osteosarcoma metastatic to the cerebellum, a site not previously described, from a primary tumor at the femur. In addition, the current literature on intracranial osteosarcoma is reviewed.

Adult↗
PubMed1998

The EASI project--improving the effectiveness and quality of image-guided surgery.

In recent years, advances in computer technology and a significant increase in the accuracy of medical imaging have made it possible to develop systems that can assist the clinician in diagnosis, planning, and treatment. This paper deals with an area that is generally referred to as computer-assisted surgery, image-directed surgery, or image-guided surgery. We report the research, development, and clinical validation performed since January 1996 in the European Applications in Surgical Interventions (EASI) project, which is funded by the European Commission in their "4th Framework Telematics Applications for Health" program. The goal of this project is the improvement of the effectiveness and quality of image-guided neurosurgery of the brain and image-guided vascular surgery of abdominal aortic aneurysms, while at the same time reducing patient risks and overall cost. We have developed advanced prototype systems for preoperative surgical planning and intraoperative surgical navigation, and we have extensively clinically validated these systems. The prototype systems and the clinical validation results are described in this paper.

Quality of Health Care↗
PubMed1998

Posterior communicating artery aneurysm presenting with haemorrhage into an arachnoid cyst.

A patient is reported on with a subarachnoid haemorrhage (SAH) from an aneurysm of the posterior communicating artery, who initially presented with a sentinel bleed into an arachnoid cyst and normal magnetic resonance angiography (MRA) of the intracranial vasculature which led to a delay in diagnosis. Although this is a very rare presentation of a relatively common condition, it is important to recognise the importance of intracystic haemorrhage in such circumstances as well as the limitations of MRA, as a delay in diagnosis may have serious clinical consequences.

Adult↗
PubMed1998

Postimaging brain distortion: magnitude, correlates, and impact on neuronavigation.

OBJECT: This prospective study was conducted to quantify brain shifts during open cranial surgery, to determine correlations between these shifts and image characteristics, and to assess the impact of postimaging brain distortion on neuronavigation. METHODS: During 48 operations, movements of the cortex on opening, the deep tumor margin, and the cortex at completion were measured relative to the preoperative image position with the aid of an image-guidance system. Bone surface offset was used to assess system accuracy and correct for registration errors. Preoperative images were examined for the presence of edema and to determine tumor volume, midline shift, and depth of the lesion below the skin surface. Results were analyzed for all cases together and separately for four tumor groups: 13 meningiomas, 18 gliomas, 11 nonglial intraaxial lesions, and six skull base lesions. For all 48 cases the mean shift of the cortex after dural opening was 4.6 mm, shift of the deep tumor margin was 5.1 mm, and shift of the cortex at completion was 6.7 mm. Each tumor group displayed unique patterns of shift, with significantly greater shift at depth in meningiomas than gliomas (p = 0.007) and significantly less shift in skull base cases than other groups (p = 0.003). Whereas the preoperative image characteristics correlating with shift of the cortex on opening were the presence of edema and depth of the tumor below skin surface, predictors of shift at depth were the presence of edema, the lesion volume, midline shift, and magnitude of shift of the cortex on opening. CONCLUSIONS: This study quantified intraoperative brain distortion, determined the different behavior of tumors in four pathological groups, and identified preoperative predictors of shift with which the reliability of neuronavigation may be estimated.

Adolescent↗
PubMed1998

Infective and traumatic aneurysms.

Traumatic intracranial aneurysms are rare lesions but should be considered in penetrating head injury, particularly in cases of low-velocity gunshot wounds or stab wounds to the head. Because most of these aneurysms are false aneurysms, treatment may require excision or trapping procedures.

Anti-Bacterial Agents↗