Tehran University Medical Journal

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It is generally assumed that local muscular fatigue predisposes the individual to injury. Despite the significance of muscular fatigue and endurance, there are not much dynamic endurance studies for trunk muscles in the literature. Most of them have used isokinetic dynamometer which keeps the velocity of movement constant. In this studies with the help of an isoinertial dynamometer we have assessed the effect of repetitive and fatiguing flexion-extension movements patterns and motor output. 38 female subjects with no history of low-back pain for the 6 months volunteered for the study. A triaxial dynamometer was used that simultaneously provided measurement of torque, angular position, velocity impulse, work and power of each axis. Resistance were set independently for each axis by an interfaced computer. The subjects performed trunk flexion and extension movement against a saggital plane resistance equal to 50% of their maximum isometric extension strength in the upright position. The minimum resistance in the coronal and transverse planes were set-up at 5-7 Newton meters. The subjects were asked to perform trunk movement as quickly and as accurately as possible while exerting the maximum efforts until exhaustion. Immediately after dynamic test another isometric test was performed. A paired T-test procedure was performed among the selected parameters of the 1st middle and last 3 repetition cycles. The selected parameters are range of motion, velocity, torque, impulse, work, power, time interval and time of movement. Also, a paired T-test was performed between maximum isometric strength before and after dynamic test. All the selected parameters were significantly reduced in the saggital plane. Subjects displayed significantly less motor control and greater range of motion in the coronal and transverse planes in performing the primary task of flexion and extension. The reduction of the functional capacity of the primary muscles performing the required task is compensated by secondary muscle groups and the spinal structures is located in a more injury prone position, as identified by finite element models. In addition it is suggested that the fatigued muscles would be less able to compensate any perturbation in the load or position of the trunk. The repetitive loading results in a weakening of the viscoelastic passive elements of the spineless structure. The loss of ability to protect these weakened passive elements makes the spine susceptible to industrial and recreational injuries.

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Background: Failed endotracheal intubation is one of the principal causes of morbidity and mortality in anesthetized patients. If the anesthetist can anticipate which patients may be more difficult to intubate, can reduce the risks of anesthesia greatly and be more prepared for any difficulties that may occur. The aim of this study was to investigate the inability of patients to protrude the lower jaw in predicting difficult intubation.
Methods: In this prospective study, we enrolled 300 patients, above 16 years of age or older, who were scheduled for elective surgery. For all of the patients, before each operation, a single anesthesiologist measured the temporomandibular mobility, which was defined as the difference between the distances, from the lower incisors to the upper incisors in a neutral position and at maximum mandibular protrusion. At the time of intubation, another anesthesiologist, blinded to the preoperative airway assessment test, performed a laryngoscopy in which the laryngoscopic view of the larynx was determined according to the Cormack and Lehane scoring system. Difficult intubation was defined as laryngoscopic views of grade III and IV.
Results: Twenty-one patients were identified as having difficult intubation. Only one patient could not be intubated. The forward movement of the mandible was significantly greater in patients with easy intubation compared to those with difficult intubation (6.42±1.95 mm vs. 3.58±1.26 mm respectively, P<0.001). The use of a cut-off point of less than 5 mm for prediction of difficult intubation showed a sensitivity of 92.86% and a specificity of 70.43%.
Conclusion: The forward movement of the mandible is significantly greater in patients with easy intubation compared those with difficult intubation Although infrequent difficulties may arise, most patients that do not have indicators of difficult intubation will be easy to intubate under anesthesia.

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Background: Constraint-Induced movement therapy (CIMT) is a promising treatment for improving upper limb function in adults after stroke and traumatic brain injury. It involves constraint of the less affected limb and intensive practice with the more affected limb. The purpose of this study on children with hemiplegic cerebral palsy (CP) was to evaluate the effects of CIMT on upper extremity and to make a comparison with conventional treatment. Methods: I a randomized clinical trial twelve children (seven females, five males aged between 48 and 72 months with mean±standard deviation of 59.91±9.15mo) were randomly assigned in two groups. An intensive occupational therapy program including five hours per day for 21 consecutive days was performed for all of them, while less affected limbs were placed in sling for immobilization. Before and after intervention, upper extremity function, spasticity, and motor neuron excitation were evaluated by means of peabody developmental motor scales, modified Ashworth scale, and H reflex and H/M ratio, respectively. Results: The children who received CIMT did not improved their ability to use their hemiplegic hand significantly more than the children in the control group (p>0.05). However, reports of caregivers and clinical observations showed increases in more affected limb frequency of use and quality of movement. Conclusion: Results suggest that the use of CIMT needs to more studies and should be considered experimental in children with hemiplegic CP

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Background: True umbilical cord knot is one of the abnormalities of the umbilical cord. Active fetal movements create cord knotting. True umbilical cord knots are rare but may be associated with fetal distress and stillbirth. True umbilical cord knots are capable of impeding blood flow to the fetus.
Case presentation: A 26-year old primigravid woman was first treated for genital herpes simplex virus (HSV type 2) at 36 weeks of gestational age. She received oral acyclovir (400 mg three times daily for 10 days). At the gestational age of 38 weeks and 5 days, fetal activity decreased and NST was nonreactive. She was delivered by cesarean section and a true umbilical cord knot was found. Four years later, in her second pregnancy, another true knot was seen.
Conclusion: Excessively long umbilical cords are more likely to be associated with true knots. Genetics has an important role in determining cord length and occurrence of true knots.

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