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Biomedical subjects

N D Kitchen

Publications and source records attributed to N D Kitchen.

69 records · Page 4Linked to original sources

Long-term follow up of dorsal root entry zone lesions in brachial plexus avulsion.

The long-term results of 44 patients who underwent dorsal route entry zone (DREZ) lesioning for pain secondary to brachial plexus avulsion are reported with a mean clinical follow up period of 63 months. The postoperative analgesic effect was judged by the patients as being good (greater than 75% pain reduction), fair (25-75% pain reduction), or poor (0-25% pain reduction). With these criteria 35 patients (77%) had continuing good (30 cases, 68%) or fair (five cases, 11%) pain relief at the time of final follow up. Eight cases (18%) had persisting neurological deficits, although these were generally mild. DREZ thermocoagulation is an effective procedure for relieving deafferentation pain. The analgesic effect which is produced in the early postoperative period seems to be maintained in the long-term.

Adult↗

Accurate frameless registration of MR and CT images of the head: applications in planning surgery and radiation therapy.

PURPOSE: To evaluate the feasibility and efficacy of a three-dimensional image registration technique for planning skull base surgery, performing frameless image registration for stereotaxic neurosurgery, and staging nasopharyngeal carcinoma. MATERIALS AND METHODS: Computed tomographic (CT) and magnetic resonance (MR) images from 35 patients were registered by identifying 12-16 homologous landmarks with each modality. Images were displayed as overlaid sections or rendered three-dimensional scenes. The clarity of the combined images from 15 patients undergoing skull base surgery was compared with that of the conventional displays. RESULTS: Images were combined for three applications, with an accuracy of 1-2 mm. For the 15 patients undergoing skull base surgery, the combined images were significantly better at depicting the relationship between bone and lesion than conventional display (P < .01). CONCLUSION: MR and CT images of the head can be accurately registered without using external markers or substantially altering image acquisition protocols. The resulting images can show the radiologic information more clearly than conventional viewing.

Adult↗

Ossification of the posterior longitudinal ligament mimicking cord compression from a dorsal disc protrusion: a cautionary tale.

A patient with focal anterior compression of the dorsal cord at the level of the D6/7 disc was mistakenly diagnosed as a dorsal disc protrusion on the basis of CT myelography. The CT scanning had been confined to axial views at the level of the cord compression. A transthoracic exploration failed to reveal a disc protrusion and the correct diagnosis, ossification of the posterior longitudinal ligament, was only revealed by a subsequent sagittal CT scan. This case emphasizes the dangers of relying on limited axial imaging in diagnosing a spinal lesion.

Diagnostic Errors↗

Ruptured intracranial aneurysms--learning from experience.

The outcome of treatment of 400 consecutive patients with ruptured intracranial aneurysms was assessed at 1 year. The patients were treated by a single surgeon over a period of 13 years. Data sheets completed as each patient was treated included a contemporary analysis of the reasons for any unsatisfactory outcome. Surgery was usually delayed for over 10 days from the last haemorrhage. Over the four successive 100-patient cohorts, in which the composition of the patient population remained unaltered, 1 year overall management mortality fell steadily from 38 to 24%. One year surgical mortality fell from 19 to 3%. The population of those operated on who were in Glasgow Outcome Score 5 at 1 year rose from 73 to 90% (from 51 to 71% for all patients). Of the 123 deaths, 89 occurred prior to operation, 24 after it. Thirty-five patients died from rebleeding prior to operation, but only eight of these occurred in patients judged fit for surgery at the time. All but one of the postoperative deaths resulted from technical problems related to the surgery. Over the successive cohorts, several factors indicated an improvement in operative efficiency, notably a fall in the proportion of cases with technical problems from 15 to 1%. We have demonstrated a steady improvement in management results, resulting largely from increasing operative experience. We do not believe that changes in overall management strategy, such as early surgery, would have any effect on overall outcome.

Adult↗

Open stereotactic amygdalohippocampectomy--clinical, psychometric, and MRI follow-up.

The clinical results of six cases of open stereotactic amygdalohippocampectomy for medically intractable epilepsy are presented. Outcome in terms of seizure control (highly satisfactory in five patients) and neuropsychological sequelae (all cases had poor functioning of the contralateral temporal lobe pre-operatively) are detailed. In addition the use of post-operative Magnetic Resonance Imaging (MRI) is demonstrated and shown to be a valuable tool in providing the crucially accurate baseline that is required for more meaningful follow-up outcome studies.

Adult↗

The value of per-operative smear examination during stereotactic biopsy.

Sixty-two consecutive CT-directed stereotactic biopsies were studied retrospectively to determine the value of the per-operative smear examination. Overall, in 69% of cases the immediate smear result agreed with the definitive histology. However, a smear diagnosis of malignant glioma was more reliable than that of metastasis (with 100% and 55% agreement with the final result respectively). In those cases where the final histological diagnosis was that of malignant glioma, immediate smear preparations taken from the hypodense centre were found to be more reliable than those taken from the enhancing edge.

Biopsy, Needle↗

Accuracy in frame-based and frameless stereotaxy.

Stereotactic surgery is currently undergoing great changes with a large number of frameless methodologies being developed alongside traditional frame-based systems. As a result, there is considerable uncertainty over the future clinical roles of the numerous stereotactic options now offered. We have reviewed the current scientific issues regarding accuracy in both frame-based and frameless stereotaxy. Frame-based systems have the advantage of proven clinical utility and instrument carriage with a high degree of mechanical stability and accuracy. Frameless methods are more complex, but also more flexible, and may have wide applications in general neurosurgery if clinical efficacy is confirmed.

Humans↗

Volumetric analysis of epilepsy surgery resections using high resolution magnetic imaging: technical report.

A method is described for accurately measuring the volume and site of epilepsy surgery resections utilizing magnetic resonance imaging. Accuracy has been assessed using post-mortem studies, and both the intra- and interobserver variability is consistently less than 5%. The technique has so far been applied to 25 patients following a variety of operations for medically intractable epilepsy. It provides the crucially accurate baseline required for meaningful follow-up outcome studies of epilepsy surgery. Consequently, it should allow the development of more precise prognostic indices for such operations.

Brain↗

Intracranial tumours in the elderly: the effect of age on the outcome of first time surgery for meningiomas.

We have investigated the effect of age on the outcome of first time surgery for intracranial meningiomas. In a retrospective study, 144 consecutive patients were divided into three groups: young (up to 44 years of age, 38 patients), middle-aged (45-64 years, 60 patients) and elderly (65 years and over, 46 patients). Outcome was assessed at the first follow-up appointment 4-6 months after discharge. The surgical mortality was 2.7%. The incidence of significant intercurrent disease increased with age (11, 25 and 35%, respectively), as did the incidence of postoperative complications (16, 23 and 30%). Postoperative intracranial bleeding was especially age-related, occurring in 20% of the elderly group as against 0% of the younger. Although the younger patients did best (100% in Glasgow Outcome Scale Grade 5) there was no difference in outcome between the middle-age and elderly groups (88 and 83%, respectively). Of the elderly patients, 89% showed clear functional improvement after surgery, 2% were unchanged and 9% were worse or dead. The intellectual deterioration apparent in over half of the elderly patients recovered after removal of the tumour in 80%. We conclude that age has little effect on the prospects of success after removal of an intracranial meningioma.

Adult↗

Racial distribution of aneurysms in Zimbabwe.

The distribution of aneurysms amongst African and Caucasian patients in two hospitals in Zimbabwe was surveyed in a retrospective study. Aneurysms were more common amongst the Caucasian patients and abdominal aortic aneurysms predominated (85%). Amongst the African patients there was a high incidence of thoracic aortic aneurysms (42%). Possible roles of atherosclerosis and syphilis in explaining these results are discussed.

Adolescent↗

Contrast-enhanced MR angiography of intracranial giant aneurysms.

BACKGROUND AND PURPOSE: Intravoxel phase dispersion and flow saturation often prevent adequate depiction of intracranial giant aneurysms on 3D time-of-flight (3D-TOF) MR angiography (MRA). Additional diagnostic difficulties may arise from T1 contamination artifact of an associated blood clot. Our aim was to assess whether contrast-enhanced MRA could improve the evaluation of giant aneurysms and to compare two different types of contrast-enhanced MRA. METHODS: We studied 11 aneurysms in 10 patients (age range, 31-77 years) with giant aneurysms of the anterior (n = 9) and posterior (n = 2) cerebral circulation by comparing 3D-TOF, first-pass dynamic contrast-enhanced MRA, and steady-state contrast-enhanced 3D-TOF sequences. Additional comparison with digital subtraction angiography (DSA) was performed in eight aneurysms. RESULTS: In nine of 11 aneurysms, 3D-TOF did not adequately show the lumen and exiting vessels. Contrast-enhanced 3D-TOF and dynamic contrast-enhanced MRA showed the aneurysm sac and exiting vessels in all of these cases. Dynamic contrast-enhanced MRA showed a better intravascular contrast than did contrast-enhanced 3D-TOF, which led to better delineation of the aneurysms. T1 contamination artifact from intra- or extraluminal blood clot was evident on the 3D-TOF images in four cases. The artifact was less marked on the contrast-enhanced 3D-TOF image and was completely eliminated on the dynamic contrast-enhanced MRA image by subtraction of precontrast images. The diagnostic information provided by dynamic contrast-enhanced MRA was comparable to that provided by DSA. CONCLUSION: Precontrast 3D-TOF is inadequate for the assessment of giant cerebral aneurysms. Both contrast-enhanced 3D-TOF and dynamic contrast-enhanced MRA reliably show the aneurysm sac and connected vessels. Dynamic MRA provides a superior contrast between flow and background and eliminates T1 contamination artifact. It should therefore be considered as the MRA sequence of choice.

Adult↗