Anatomic and technical considerations in needle electromyography of the lumbar spine

Interpretation of the paraspinal needle electromyographic examination requires knowledge of complex and specialized anatomy and pathophysiological processes. The purpose of this article is to elucidate the anatomy and physiology of the lumbar paraspinal needle examination and apply this knowledge to accurate needle technique and rational clinical interpretation of the paraspinal examination.

Plantar pressures with total contact casting

Total contact casting has been used to aid in the healing of plantar neurotrophic ulcerations. The efficacy of total contact casts in promoting ulcer healing is presumably due to a reduction in the load over high pressure areas with pressure redistribution over the entire surface of the foot. The purpose of this study was to quantify the effectiveness of total contact casting in reducing plantar pressures. A portable microprocessor-based data-acquisition system was used for recording plantar pressures. Plantar pressures were collected from six nondisabled individuals with and without total contact casting at cast-walking cadence. In our study, there was a decrease in plantar loading under the metatarsal heads (first, fourth, fifth), the great toe, and the heel. The average decrease was 32% under the fifth metatarsal, 63% under the fourth metatarsal, 69% under the first metatarsal, 65% under the great toe, and 45% under the heel. Our study quantitatively showed that total contact casting does reduce vertical plantar pressures in high load areas.

Influence of pretreatment with a monoamine oxidase inhibitor (phenelzine) on the effects of buprenorphine and pethidine in the conscious rabbit

The existence of a severe toxic interaction (occasionally fatal) from the clinical use of pethidine and monoamine oxidase (MAO) inhibitors is well established. The present study evaluates the possibility of such an interaction existing for the opioid partial agonist buprenorphine. Conscious rabbits (n = 6 in each group) pretreated 18-24 h previously with physiological saline or the MAO inhibitor phenelzine 20 mg kg-1 s.c. were subsequently given physiological saline, pethidine 5 mg kg-1 i.v. or buprenorphine 0.1 or 1.0 mg kg-1 i.v. Whilst saline was without effect and phenelzine produced only a small increase in the rabbit temperature, the combination of phenelzine and pethidine produced a marked, prolonged hyperpyrexia (+4.4 +/- 0.19 degrees C; P less than 0.001), hypertension (+33.9 +/- 3.1 mm Hg; P less than 0.01) and agitation. Three rabbits died, at 35, 45 and 55 min after the pethidine-phenelzine combination. Buprenorphine was without significant effect on any parameter when given after phenelzine. In the model used buprenorphine, in contrast to pethidine, showed no interaction with the MAO inhibitor phenelzine.

Comparison of the alpha-adrenoceptor profiles of clonidine and two oxygenated arylamino imidazolines

The profiles of 2-(3,4-dimethoxyphenylamino)-imidazoline HCl (RX 77171) and 2-[6-(1,4-benzodioxanylamino)]imidazoline maleate (RX 801074) were compared with that of clonidine in isolated tissues and pithed rats. RX 77171 consistently displayed prejunctional alpha 2-adrenoceptor antagonist and postjunctional agonist properties. In contrast, RX 801074 had a complex profile which showed considerable variability between tissues. This variability is highlighted by comparing its effects at the prejunctional alpha 2-adrenoceptors of the isolated vas deferens and guinea-pig ileum; in the former RX 801074 was an agonist whereas only antagonist properties were apparent in the ileum.

Studies on the pre- and postjunctional activities of alpha-adrenoreceptor agonists and their cardiovascular effects in the anaesthetized rat

1 The selectivity of a number of agonists for peripheral alpha 1- and alpha 2- adrenoreceptors was determined and related to their cardiovascular effects in pentobarbitone-anaesthetized rats. 2 In isolated tissues, presynaptic alpha 2- and postsynaptic alpha 1-adrenoreceptor activity was determined on the rat vas deferens and anococcygeus muscle respectively. Xylazine, guanabenz, guanoxabenz and guanfacin were more selective, whilst lofexidine, tiamenidine, naphazoline, oxymetazoline and St 91 were less selective than clonidine for presynaptic alpha 2-adrenoreceptors. 3 The anococcygeus muscle of the pithed rat was used to determine the alpha-adrenoreceptor selectivity of the compounds in vivo. The selectivities were similar to those obtained in vitro. 4 Following intravenous administration to pentobarbitone-anaesthetized rats guanabenz and guanfacin caused small transient pressor responses and a prolonged secondary hypotension. In contrast oxymetazoline and St 91 produced marked initial pressor responses and the secondary reduction in blood pressure was absent. Clonidine and tiamenidine produced marked initial pressor responses followed by secondary hypotensive effects. All compounds reduced heart rate. 5 Intracerebroventricular (i.c.v.) administration of clonidine, guanabenz and guanfacin elicited falls in blood pressure and heart rate. In contrast blood pressure was either unaffected or elevated following i.c.v. administration of St 91, oxymetazoline and tiamenidine. 6 It is concluded that in the normotensive rat, central alpha 2-adrenoreceptors play a major role in the hypotensive effects of clonidine and related compounds.

Prophylactic antibiotics in vascular surgery. Topical, systemic, or both?

A prospective, randomized, blinded study was performed to determine whether prophylactic antibiotics would reduce the incidence of infection in peripheral vascular surgery and whether the route of antibiotic administration was important. Patients undergoing a vascular procedure with a groin incision were allocated to one of four groups with respect to prophylactic antibiotics. Group I received no antibiotic. Group II had topical cephradine instilled in their incisions prior to closure. Group III received a 24-hour perioperative course of intravenous cephradine, and Group IV received both topical and intravenous cephradine. Groin and abdominal incisional infections were significantly reduced (p < 0.01) among patients who received prophylactic antibiotics by either the topical, systemic, or combined routes of administration. No significant differences were noted among the three antibiotic groups. Profundoplasty, femoral embolectomy, and femoral aneurysm repair were each associated with an increased incidence of infection (p < 0.01). Other risk factors were only important in patients not receiving antibiotics. Either intraoperative topical antibiotics or perioperative systemic antibiotics prevent infection in peripheral vascular surgery, but antibiotic administration by both routes is unnecessary.