Percutaneous radiofrequency rhizotomy of lumbar spinal facets: The results of 46 cases

The results of percutaneous radiofrequency rhizotomy of lumbar spinal facets in 46 patients followed at least three months (mean 15 months) are reported and compared with those reported previously. Satisfactory pain relief three months after the procedure was achieved in 36.4 percent of patients without operations and in 41.7 percent of patients with operations other than fusion.No patient had previously undergone fusion.Treatment of low-back pain by using radio-frequency thermocoagulation of spinal facets is a simple, safe, and well-tolerated procedure. It can be used to relief of pain in spite of decreasing rates of success within the follow-up period.     

The effects of verapamil on left ventricular function in the presence of beta-adrenergic blockade

Supraventricular tachyarrhythmias frequently complicate myocardial revascularization. Intravenous administration of verapamil has been effective in terminating these arrhythmias. To determine the effects of verapamil on left ventricular systolic function, we implanted ultrasonic dimension transducers in dogs and, after they had recovered from the operation, studied them while they were awake and unsedated. Intravenous administration of verapamil (0.2 mg/kg) resulted in an elevation of cardiac output above baseline because of reflex-induced tachycardia. Contractility, as measured by the load-independent end-systolic pressure-volume relationship, remained unchanged. When the animals were pretreated with atropine and propranolol, verapamil resulted in a fall in cardiac output and contractility. The intact animal responded to the vasodilatory effect of verapamil by releasing catecholamines to maintain cardiac output and hemodynamic stability. Only when this compensatory mechanism was blocked by a beta-adrenergic blocker do the inherently negative inotropic and chronotropic effects of verapamil become apparent. The clinical ramifications of this finding are of greater importance to the surgeon as more patients receive beta-adrenergic blocking agents up to the time of the immediate preoperative period. We conclude that verapamil should be administered with caution to patients with supraventricular tachyarrhythmias who have been receiving beta-adrenergic blocking agents.     

The effect of Bosentan on healing of colonic anastomosis

Background  

Ischemia is the most important factor compromises wound healing in colonic anastomosis. Mesenteric vessels are ligated at first while performing colonic resection and following anastomosis. Therefore blood supply of the related segments of colon temporarily interrupted and ischemia can easily occur. This study was carried out to explore whether Bosentan, an endothelin-receptor antagonist, can eliminate vasoconstruction, increase blood flow in the splanchnic area and anastomotic region and therefore possibly facilitate wound healing and prevent intra-abdominal adhesion formation.     

Perceptions of first and third year medical students on self-study and reporting processes of problem-based learning

Background  

The objective of this study is to investigate the perceptions of first and third year medical students on self-study and reporting processes of Problem-based Learning (PBL) sessions and their usage of learning resources.