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S Valenzuela

Publications and source records attributed to S Valenzuela.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Screwing the odontoid process. A functional operation].

The authors describe a case of direct screw fixation of the odontoid process via an anterolateral retropharyngeal subhyoid pre-sternomastoid approach and discuss the indications for this operation. In this particular case, immobilization by a cervical collar or a halo vest was not chosen because of its constraining character and the risk of secondary displacement and pseudarthrosis. C1-C2 or occipitospinal arthrodesis, whether performed via a posterior, lateral or anterior approach, is difficult to perform and always leads to a functional handicap. The transoral approach does not allow direct screw fixation of the dens. Dens screwing via an anterior pre-sternomastoid subhyoid approach is the most logical and least disabling technique. The subhyoid approach is much simpler than the suprahyoid approach. This technique is used in fractures of the odontoid process with an ablique downward and backward fracture line, with or without arch fracture of C1, and allows screwing perpendicular to the fracture line. Considering the present results and the literature, the double screw fixation does not seem to be justified.

Adult↗
PubMed1989

[Prolonged intergenesic period. A high risk factor?].

A prospective study is effected in 115 pregnant patients with an intergenesic period (IGP) of 7 years or more and it is compared with an equal number of patients with a minor IGP to this age. From these patients, 86 (74.8%) do not present pathology and 29 (25.2%) present it. These groups are divided in turn in two categories, from 35 years old to more and minors to this age. Differences are not found in the form of beginning parturition, way of this form of membranes breakage, duration of working of parturition and expellant between both independent groups to the maternal age. The perinatal results are alike except a minor average weight in mothers with prolonged IGP children. The patients with pathology were managed according to this, independent to their IGP. In conclusion only patients with prolonged IGP must be managed as high risk, when they present furthermore associated pathology and those patients with prolonged IGP independent to this duration have raised possibilities of success in vaginal parturition in absence of pathology.

Adult↗
PubMed1989

[Demographic trends: birth spacing].

Two studies to measure children spacing in western metropolitan Santiago are compared. The first (1984-85) surveyed a sample of 687 mothers and the second 1,000. Deliveries took place at San Juan de Dios and Félix Bulnes hospitals (both state-finance) which provide medical care for medium and low income groups. Long spacing (5 years or more) accounted for the highest proportion of non-first born children (33.8% in 1984-85 with a significant increase to 40.1% in 1988) while short spacing (under 2 years) accounted for 19.2% in 1984-85 and 21.8% in 1988 (not significant). Mean birth weights were over 3,200 g in every spacing group. Despite the low illiteracy rate, predominant urban origin and having at least one child born before, high proportions of children were conceived despite the use of contraceptive measures (19.7% in 1984-85 and 22.5% in 1988). This contraceptive failure was less frequent among children born after longer spacings.

Birth Intervals↗
PubMedDate not supplied

Inhibition of xylazine induced uterine contractility by clenbuterol and nifedipine.

A study was undertaken in order to determine the effects of xylazine on uterine contractility in goats premedicated with clenbuterol or nifedipine. These drugs inhibit uterine activity by acting as potent tocolytic or uterine relaxant agents. A balloon-tipped catheter was inserted under sedation and local anaesthesia on to a uterine horn in 15 cycling goats in order to record intrauterine pressure changes. Three groups of five goats were used: group I was treated with an intravenous dose of 0.1 mg kg-1 of xylazine. Groups II and III were pretreated with 4 micrograms kg-1 of clenbuterol and 80 micrograms kg-1 of nifedipine, respectively, before administrating the same dose of zylazine. Xylazine increased the frequency and intensity of uterine contractions significantly and the value of the area under the contraction curves was significantly higher than that observed under basal conditions i.e. before drug treatment. In goats premedicated with clenbuterol or nifedipine, the uterotonic effects of xylazine (2858 +/- 217 versus basal contractility: 1241 +/- 173 mm2.5 min-1, P < 0.05) were inhibited for the 30 minutes recording period. These data indicate that clenbuterol and nifedipine can be used as potent tocolytic agents in order to prevent the uterine side effects of xylazine.

Adrenergic alpha-Agonists↗