Electromyography of the internal anal sphincter performed under endosonographic guidance description of a new method

PURPOSE: The aim of our study was to investigate internal anal sphincter electromyographic signals. METHODS: Electromyography of the internal anal sphincter was performed with platinum wire electrodes in six healthy volunteers (three males and three females), inserted under endosonographic guidance. Platinum wire electrodes were also inserted into the external anal sphincter. Activity of both the internal and external anal sphincter in a 40-second period was measured. RESULTS: Internal anal sphincter median activity was 22.1 (range, 5.5–67.6) μ V. Slow-wave activity was 47 cycles/minute (range, 34–55 cycles/minute). After inflation of a rectal balloon with air until a constant relaxation of the anal canal was obtained, a decrease in internal anal sphincter activity to 15.9 (1.2–31.3) μV as well as a decrease in slow-wave activity to 34 cycles/minute (range, 27–40 cycles/minute) was found. The original internal anal sphincter EMG was resumed after deflation of the rectal balloon. External anal sphincter median activity was 31 (range, 0.77–18.6)μV. During inflation of the rectal balloon, a reflex increase in external sphincter EMG activity was found. With the rectal balloon fully inflated a part of this increase was still present, 11.0 (1.9–24.6)μV. In some of the subjects, this increased activity was superimposed on the internal anal sphincter recordings as well. During a voluntary squeeze it was not possible to identify internal anal sphincter activity due to activity of the external anal sphincter totally overriding the internal anal sphincter signal. CONCLUSION: Precise EMG recordings from the internal anal sphincter is possible with endosonographic guidance of the electrodes, except during voluntary squeezing of the external anal sphincter.     

Cardiac function predicts mortality following thoracoabdominal and descending thoracic aortic aneurysm repair.

OBJECTIVE: Previous studies have identified age, renal failure and aneurysm extent as predictors of mortality following thoracoabdominal and descending thoracic aortic aneurysm (TAA) repair. We studied the impact of coronary artery disease (CAD) and cardiac function on 30-day mortality following TAA repair. METHODS: Between February 1991 and May 2001, we performed 854 TAA repairs. Two hundred ninety-one patients (34%) had a history of coronary artery disease. One hundred forty-one/291 (49%) had undergone coronary artery bypass surgery (CAB) prior to TAA repair. We conducted multivariable analyses of known risk factors along with the left ventricular ejection fraction (EF) and prior CAB to determine the adjusted effect of CAD on outcome. RESULTS: Mortality in patients with CAD was 54/291 (18%) compared to 75/563 (13%) without CAD (P<0.05). In patients who had prior CAB, mortality was 31/141 (22%) compared to 98/713 (14%) patients without prior CAB, (P<0.02). In multivariable analysis, the effects of CAD and CAB on mortality were eliminated by consideration of a low EF (defined as less than 50%). CONCLUSION: Impaired left ventricular function appears to be the strongest cardiac predictor of mortality for TAA repair, independent of the presence of coronary artery disease or coronary artery bypass revascularization.     

Abnormalities of somatosensory evoked potentials in the quinolinic acid model of Huntington's disease: evidence that basal ganglia modulate sensory cortical input.

Intrastriatal injection of quinolinic acid (QA) in rats provides an animal model that mimics some of the neuropathological and neurochemical alterations observed in the striatum of patients with Huntington's disease (HD). One of the very early neurophysiological signs in HD is a diminution of amplitude of early somatosensory evoked potentials (SEPs) recorded over the parietal cortex. The present study investigated whether the QA model exhibits similar neurophysiological abnormalities. Two weeks after unilateral intrastriatal injection of QA (240 nmol) or of the solvent, early SEPs were recorded with chronically implanted electrodes from the somatosensory cortex or from the ventrobasal nucleus of the thalamus of lightly pentobarbital-anesthetized rats, in response to single-shock electrical stimulation of the contralateral forepaw. Whereas intrastriatal injection of solvent did not influence SEPs, the striatal QA lesion significantly reduced the amplitude of early cortical SEPs by about 40% without affecting the latency. SEPs recorded from the ventrobasal nucleus were unchanged after QA lesion. Histological examination and glial fibrillary acid protein staining after intrastriatal injection of QA revealed no evidence for damage in the somatosensory system. It is concluded that (1) the QA animal model of HD mimics some of the SEP abnormalities of patients, and (2) a striatal lesion modulates somatosensory transmission to the cortex in rats.     

Lateral Skull Base Surgery: The Otology Group Experience

Lateral skull base surgery has remained the surgical frontier of new developments in the treatment of lesions heretofore difficult to access. Examination of surgical results stimulates technical innovation and provides an intervention risk-benefit ratio assessment for particular lesions useful in management planning. With this in mind, we report the updated collective experience with lateral skull base surgery at the Otology Group over the past 20 years. Two hundred ninety-eight patients underwent surgical intervention for lateral skull base lesions. In 81 patients these lesions were malignant; in 217, benign. Of the benign lesions, 165 were glomus tumors: 139 glomus jugulare, 19 glomus vagale, and 7 glomus tympanicum. The remainder comprised 21 menigniomas, 14 neuromas, two neurofibromas, and a small group of much rarer entities. The philosophy of surgical approach, results, and follow-up are discussed.     

In vivo carbon monoxide exposure and hypoxic hypoxia stimulate immediate early gene expression

 This study aimed to examine the influence of acute tissue hypoxygenation on the expression of immediate early genes in different rat tissues. To this end male Sprague-Dawley rats were exposed to 0.1% carbon monoxide for 0.5, 1 and 6 h or to 9% oxygen for 6 h and mRNA levels for c-jun, c-fos, c-myc and EGR-1 were assayed by RNase protection in hearts, kidneys, livers and lungs. We found that hypoxia increased c-jun mRNA levels between twofold (lung) and eightfold (liver) in all organs examined; c-fos mRNA increased between threefold (lung) and 20-fold (heart); c-myc mRNA increased between twofold (lung) and sixfold (heart); and EGR-1 mRNA increased between twofold (lung) and sixfold (heart). Our findings suggest that acute tissue hypoxygenation is a general stimulus of the expression of immediate early genes in vivo. With regard to the sensitivity to hypoxia, organ differences appear to exist in that the lung is rather insensitive, whilst the heart is rather sensitive. Received: 25 February 1997 / Received after revision: 17 June 1997 / Accepted: 19 June 1997     

Ultrasonographic measurement of shoulder subluxation in patients with post-stroke hemiplegia.

OBJECTIVE: To evaluate the ultrasonographic measurement of shoulder subluxation in patients with post-stroke hemiplegia. DESIGN: Prospective, single blind study. PATIENTS: A total of 41 patients with post-stroke hemiplegia were included (24 men and 17 women, mean age 56 years (standard deviation 11), age range 34-78 years). METHODS: Clinical evaluation of the affected shoulder was assessed using the Motricity Index scores and the Modified Ashworth Scale. Two ultrasonographic measurements were taken to check intra-rater reliability. The shoulder subluxation ratio was determined as the ratio of the radiographic vertical and horizontal distance, and the ultrasonographic lateral and anterior distances in the affected shoulder divided by that in the unaffected shoulder. RESULTS: Intraclass correlation coefficients of the repeated ultrasonographic lateral/anterior distance measurements in the unaffected and affected shoulders were 0.979/0.969 and 0.950/0.947, respectively. Ultrasonographic lateral/anterior distance ratios were negatively correlated with Motricity Index scores of the affected shoulder abduction (r = -0.490, p < 0.001/ r = -0.671, p < 0.001). Ultrasonographic anterior distance ratio was negatively correlated with Modified Ashworth Scale score of the affected shoulder (r = -0.374, p < 0.05). However, there was no correlation between radiographic distance ratios and clinical evaluation scores. CONCLUSION: We strongly recommend ultrasonography as a diagnostic tool to measure the degree of shoulder subluxation in patients with post-stroke hemiplegia.