During prolonged low-level contractions, synergist muscles are activated in an alternating pattern of activity and silence called as alternate muscle activity. Resting muscle stiffness is considered to increase due to muscle fatigue. Thus, we investigated whether the difference in the extent of fatigue of each plantar flexor synergist corresponded to the difference in the frequency of alternate muscle activity between the synergists using muscle shear modulus as an index of muscle stiffness. Nineteen young men voluntarily participated in this study. The shear moduli of the resting medial and lateral gastrocnemius muscles (MG and LG) and soleus muscle (SOL) were measured using shear wave ultrasound elastography before and after a 1-h sustained contraction at 10% peak torque during maximal voluntary contraction of isometric plantar flexion. One subject did not accomplish the task and the alternate muscle activity for MG was not found in 2 subjects; therefore, data for 16 subjects were used for further analyses. The magnitude of muscle activation during the fatiguing task was similar in MG and SOL. The percent change in shear modulus before and after the fatiguing task (MG: 16.7 ± 12.0%, SOL: −4.1 ± 13.9%; mean ± standard deviation) and the alternate muscle activity during the fatiguing task (MG: 33 [20–51] times, SOL: 30 [17–36] times; median [25th–75th percentile]) were significantly higher in MG than in SOL. The contraction-induced change in shear modulus (7.4 ± 20.3%) and the alternate muscle activity (37 [20–45] times) of LG with the lowest magnitude of muscle activation during the fatiguing task among the plantar flexors were not significantly different from those of the other muscles. These results suggest that the degree of increase in muscle shear modulus induced by prolonged contraction corresponds to the frequency of alternate muscle activity between MG and SOL during prolonged contraction. Thus, it is likely that, compared with SOL, the alternate muscle activity of MG occurs more frequently during prolonged contraction due to the greater increase in fatigue of MG induced by the progression of a fatiguing task.
Annual UN-AN rupture rate and the utility for knowingly living with UN-AN are key factors when deciding on a therapeutic strategy. Also, updating published decision analyses can improve clinical decision making by integrating clinical judgment and newly available clinical data.
We report three extremely rare cases of Streptococcus pneumoniae meningoencephalitis (SPM) after transsphenoidal surgery (TSS). Between 2004 and 2010, we experienced three cases of severe SPM after surgery out of 1,965 patients undergoing TSS (0.15%). The three cases included a 4-year-old boy with a large cystic craniopharyngioma, a 40-year-old man with a non-functioning pituitary adenoma, and a 55-year-old man with acromegaly. The similarity among these SPM patients was that severe clinical events occurred suddenly 1–2 months postoperatively without any history of sinusitis or pneumonia. Despite intensive care these patients notably had residual neurological sequelae. In no case was rhinorrhea associated with SPM. It should be noted that SPM was not detected from bacterial cultures of the sphenoidal sinus mucous membranes (BCSM) obtained during TSS in two of the patients examined. Severe postoperative SPM can occur suddenly without cerebrospinal fluid (CSF) leakage within 2 months after surgery and requires emergency treatment. Reduced resistance to infection may play a role in the occurrence of SPM in our three patients. Our study indicates that BCSM is not useful for predicting postoperative meningitis.
We examined the operative findings of cerebral aneurysms that grew during followups over the past 5 years. We defined aneurysmal growth as form change such as the bleb formation or more than 2-mm growth compared with past findings. In operation, we confirmed a very thin wall of cerebral aneurysm correspond to aneursymal growth during follow-up.Rupture rates appear to be high in aneurysms caused by a change such as the above. Clipping can prevent aneurysmal rupture in these cases.
Key words:・unruptured cerebral aneurysm ・aneursymal growth ・operative view Surg Cereb Stroke
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