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Biomedical subjects

Frank Smith

Publications and source records attributed to Frank Smith.

9 recordsLinked to original sources
PubMed2005

The positional magnetic resonance imaging changes in the lumbar spine following insertion of a novel interspinous process distraction device.

STUDY DESIGN: Patients with symptomatic lumbar spinal stenosis underwent magnetic resonance imaging to study changes in the lumbar spine in various postures before and after implantation of the X STOP Interspinous Process Distraction Device (St. Francis Medical Technologies, Concord, CA). OBJECTIVE: To visualize the effect of the device in vivo. SUMMARY OF BACKGROUND DATA: Previous studies have shown vertebral canal and exit foraminal area to reduce from flexion to extension. Recently, reports on improved kinematics in vitro at the implantation level of the X STOP device have also been published. METHODS: Using positional magnetic resonance imaging, patients were scanned before and 6 months after surgery. Images were taken with the patient in sitting flexed, extended, neutral, and standing positions. The total range of motion of the lumbar spine and individual segments were measured, along with changes in disc height, areas of the exit foramens, and dural sac. RESULTS: In 12 patients with 17 distracted levels, the area of the dural sac at these levels increased from 77.8 to 93.4 mm after surgery in the standing position (P = 0.006), with increase in the exit foramens, but no change in lumbar posture. CONCLUSIONS: This study shows that the X STOP device increases the cross-sectional area of the dural sac and exit foramens without causing changes in posture.

Aged↗
PubMed2004

Correlation between inter-vertebral disc morphology and the results in patients undergoing Graf ligament stabilisation.

BACKGROUND: Previous studies have shown Graf ligament stabilisation procedure to give mixed results in the short to medium term. The aim of this study was to correlate the pre-operative state of the disc, multifidus muscles, age of the patient, levels operated and the clinical outcome after a mean follow-up of 47 months. METHODS: Graf ligament stabilisation procedure was carried out in 38 patients between 1996 and 1999. Their post-operative status was assessed using MacNab criteria. The post-operative follow-up was by postal questionnaires and review of the clinical notes. Disc morphology and multifidus muscle wasting was graded blindly and independently. The intra- and interobserver reliability was measured with kappa score and classified using the kappa classification of Landis and Koch. Correlation was measured with the help of Spearman correlation coefficient. RESULTS: Thirty-eight patients (100%) returned the questionnaires. Mean follow-up time was 47.55 months. Fifty-nine levels were operated on. Mean age was 39.68 years. The overall re-operation rate was 15.8%. The intra- and interobserver reliability was graded as good to substantial. Twenty-two patients (57.89%) were satisfied with the procedure. There was no statistically significant correlation between disc morphology, multifidus muscle wasting, sex, age, number of levels operated, the levels operated, and the satisfaction rate. CONCLUSIONS: The indications of Graf ligament stabilisation procedure are not clear. Further work is necessary to clearly identify the indication for the procedure.

Adolescent↗
PubMed2004

A pilot study of personal exposure to respirable and inhalable dust during the sanding and sawing of medium density fibreboard (MDF) and soft wood.

A pilot study of production of respirable and inhalable dusts from sawing and sanding medium density fibreboard (MDF) and softwood in a typical cabinet-making workshop produced high but variable exposure levels at the bench and operator position. Exposure levels for the total inhalable fraction (approximately <100 microm) were 6.9-91 mg m(-3) for MDF and 2.5-45 mg m(-3) for softwood. For the respirable fraction (< 10 microm) levels were 0.4-13 mg m(-3) for MDF and 0.4-2.9 mg m(-3) for softwood. These results show significant dust loading is produced in the coarser fraction and that the material used has a significant impact on levels produced. It suggests that fuller evaluation of operator influence of fine dust production is needed and may question the common application of a single inhalable exposure standard for wood dust to all wood working scenarios.

Air Pollution, Indoor↗
PubMed2004

Upper gastrointestinal haemorrhage following cardiac surgery: a comparative study with vascular surgery patients from a single centre.

OBJECTIVE: To compare the frequency and outcome of upper gastrointestinal haemorrhage (UGH) patients who had undergone cardiac surgery with a control group of vascular surgery patients. PATIENTS: Patients who had undergone cardiac or vascular surgery from January 1999 to December 2000 were identified from departmental records. The inclusion criteria used were haematemesis and/or melaena in the post-operative period. RESULTS: Only 20 of the 2274 (0.9%) cardiac operations were complicated by UGH compared to eight of 708 (1.1%) vascular operations. Among those with UGH, 90% of the cardiac and 43% of the vascular patients were taking aspirin, warfarin or both. The mean interval between surgery and the UGH was 9.6 days (range 1-30) for the cardiac and 6 days (range 0-15) for the vascular patients. Duodenal and gastric ulcers were the most common cause of UGH (60%) in the cardiac group. Despite endoscopic intervention, more than one third of ulcer associated haemorrhages required surgical over-sewing, but none of the patients who had surgery died. The overall mortality on the cardiac surgery patients who experienced UGH was 15%, significantly higher than the 2.3% for the whole cardiac surgery group during the study period (P = 0.00075, OR = 8, 95% confidence interval 2.3-28). However, even this mortality is less than that of general inpatients who suffer UGH (33%). CONCLUSIONS: Cardiac and vascular surgical patients have similar low post-operative rate of UGH. Post-operative UGH is associated with increased mortality after primary surgery. Early surgical intervention appears to be life saving in those patients who are too ill to compensate for the haemodynamic disturbance of untreated UGH.

Aged↗
PubMed2003

New approach to the surgical management of pulmonary arteriovenous malformations after cavopulmonary anastomosis.

The development of pulmonary arteriovenous malformations after cavopulmonary bypass in patients with congenital heart disease is well documented. We report successful management of pulmonary arteriovenous malformations after cavopulmonary bypass in a patient with an interrupted inferior vena cava (IVC) and multiple hepatic veins utilizing an extracardiac conduit from the hepatic veins to the hemiazygous continuation of the interrupted IVC. This technique, performed without circulatory arrest or an atriotomy, may limit morbidity associated with intracardiac procedures in patients with single ventricle morphology. Furthermore, this case suggests an alternative technique for completion Fontan in patients with an interrupted IVC and multiple hepatic venous drainage.

Adolescent↗
PubMed2002

Enhancing reliability in portfolio assessment: discussions between assessors.

This paper reports the reliability in assessments of a series of portfolios assembled by a cohort of participants attending a course for prospective general practice trainers. Initial individual assessments are compared with open discussion between random pairs of assessors to produce paired composite scores, and analysed using kappa statistics. Overall reliability of a global pass/refer judgement improved from a kappa of 0.26 (fair) using individual assessment, to 0.5 (moderate) with paired discussants.

Cohort Studies↗
PubMed2002

The geometry of unstented and stented pig common carotid artery bypass grafts.

The long-term success of arterial bypass grafting with autologous saphenous veins is limited by neointimal hyperplasia (NIH), which seemingly develops preferentially at sites where hydrodynamic wall shear is low. Placement of a loose-fitting, porous stent around end-to-end, or end-to-side, autologous saphenous vein grafts on the porcine common carotid artery has been found significantly to reduce NIH, but the mechanism is unclear. In a preliminary study, we implanted autologous saphenous vein grafts bilaterally on the common carotid arteries of pigs, placing a stent around one graft and leaving the contralateral graft unstented. At sacrifice 1 month post implantation, the grafts were pressure fixed in situ and resin casts were made. Unstented graft geometry was highly irregular, with non-uniform dilatation, substantial axial lengthening, curvature, kinking, and possible long-pitch helical distortion. In contrast, stented grafts showed no major dilatation, lengthening or curvature, but there was commonly fine corrugation, occasional slight kinking or narrowing of segments, and possible long-pitch helical distortion. Axial growth of grafts against effectively tethered anastomoses could account for these changes. CFD studies are planned, using 3D MR reconstructions, on the effects of graft geometry on the flow. Abnormality of the flow could favour the development of vascular pathology, including NIH.

Animals↗