Valgus stress radiography in normal ankles

Deltoid ligament injury is thought to be rare. Signs of complete rupture of the deltoid ligament may be subtle or interpreted as another injury condition and thus are often missed acutely. No standardized method has been created to evaluate medial ligament insufficiency in acute or chronic laxity. To establish a diagnostic test for suspected isolated ruptures of the deltoid ligament, 32 subjects with no previous ankle injury underwent valgus stress radiography and nonstressed radiography of both ankles. Stress radiography in this study showed that there is a measurable but minimal range of talar tilt on valgus stress in previously uninjured ankles. This study provides the basis for diagnosis of the rare isolated rupture of the deltoid ligament of the ankle.     

Tables of normal values of average and long latency auditory potentials

INTRODUCTION AND OBJECTIVE: In view of the disparity of data and methodology concerning medium (MAEP) and long latency (LAEP) acoustic evoked potentials, we have obtained tables of normal values using a reliable method and statistical study of these potentials in 30 healthy persons, in order to serve as a basis for clinical reference and for possible further studies. MATERIAL AND METHODS: In the MAEP we used the two types of stimuli most commonly employed, first a click and then a rising-plateau-falling tone (2-6-2). We observed that this did not affect the latency or amplitude of the different waves, although the best defined waves are obtained with tones. In the LAEP we always used a tone with rise-plateau-fall of 10-50-10, as recommended by the American Electroneurophysiological Society. In all cases the intensity was of 70 db, with rarefaction and masking of the contralateral ear with an intensity of 50 db. Self-adhesive electrodes were used for captation; the active one was placed on the ipsilateral ear lobe and the reference electrode in Cz for the LAEP. For the LAEP the lower filter was of 1 Hz and the higher of 70 Hz. In view of the variety of filters recommended, 10 Hz at the lower level and 500, 1000 and 2000 at the higher level were used successively for the MAEP. We observed that these did not affect the latency or amplitude of the waves, so these three values may all be used equally well. RESULTS AND CONCLUSIONS: In the inter-sexual study, no differences were seen between men and women. Nor were there significant differences between the acoustic evoked potentials on the right and left sides of the same person.     

Revascularization of the peroneal artery

In the absence of a suitable popliteal or tibial arterial system with direct communication to a pedal arch, the peroneal artery may be used for distal anastomosis with the expectation of achieving patency rates exceeding 60 per cent. Morbidity can be minimized by careful patient selection and by imporved surgical technique and materials. In 14 of 23 peroneal bypasses, patency was maintained compared with 27 to 35 bypasses to the tibial artery system. Limb salvage was 57 per cent for th peroneal artery group compared with 71 per cent for tibial artery reconstruction.     

Intraneural cyst of the peroneal nerve

A 15-year-old girl was referred to us because of foot drop. The motor deficit was characterized by a peculiar fluctuating course related to sporting activity: improvement of symptoms during no-sport periods and worsening during sport training. Neurophysiological examination revealed marked global impairment of muscles innervated by the peroneal nerve. Ultrasound and MRI showed a mass in close proximity to the neck of the fibula extending in a tubular fashion. At operation an intraneural lesion was found and was totally removed. Histology revealed that it was an intraneural cyst. A hypothesis on the pathogenesis was drawn up. One year after the operation a clinical and neurophysiological follow-up was performed.     

Short and long latency cortical potentials evoked by electrical stimulation of the oesophageal mucosa in normal alert humans

BACKGROUND: The type of remodeling of the human femoral artery (enlargement or shrinkage) is related to the percentage luminal stenosis. OBJECTIVE: To assess how local changes in vessel size, together with plaque load, determine luminal narrowing in atherosclerotic human coronary arteries. METHODS: We obtained 576 segments of 28 coronary arteries from 10 patients who had died from noncardiac causes. The lumen area and area circumscribed by the internal elastic lamina (IEL) area, a measure of local vessel size in each histologic cross-section were measured, and the mean lumen diameter and mean IEL diameter were calculated. To correct for arterial tapering, expected reference diameter values were calculated at the same location using linear regression of all data points along the artery. The IEL diameter and lumen diameter were expressed as percentages of the calculated IEL diameter and lumen diameter at the same location (percentage lumen diameter stenosis and relative IEL diameter, respectively). RESULTS: We found a negative relation between the relative IEL diameter and the percentage lumen diameter stenosis. On average, a narrower than expected lumen diameter was accompanied by a smaller than expected IEL diameter. A larger than expected lumen diameter was accompanied by a larger than expected IEL diameter. This relation was found for the left anterior descending, circumflex, and right coronary arteries (y = -0.60x + 105.33, r = 0.48; y = -0.45x + 100.69, r = 0.84; and y = -0.39x + 101.84, r = 0.61, respectively, all P < 0.05). CONCLUSIONS: Local luminal narrowing was correlated with a decrease in vessel size. Local remodeling of the artery is one of the determinants of luminal narrowing in the atherosclerotic human coronary artery.     

Luminance and color contrast sensitivity and VEP latency in subjects with normal and defective binocularity

The effect of an additive (Brij 35) on the mobilities of a group of porphyrin acids is quantitatively characterized based on a 1:1 dynamic complexation model. Varying additive concentration shifts the equilibrium and changes the viscosity of the background electrolyte. The equilibrium constant, the electrophoretic mobility of the free analyte, and the electrophoretic mobility of the complex are identified as the parameters necessary to describe the analytes' migration behavior. Several statistical methods for obtaining these parameters are discussed. The equilibrium constants and complex mobilities are calculated using three different linear regression methods. The weighted y-reciprocal method was preferred because it gives smaller error, and the data points are evenly distributed along the concentration axis. These values are confirmed using a nonlinear regression to ensure that the proper weighting was used in the linear regression plots. The parameters are then used to predict the apparent mobilities of the analytes over the entire additive concentration range, allowing the optimum separation conditions to be identified. For disc-like molecules, such as porphyrins, the mobility is determined by the orientation of the molecule in an electric field, in addition to their size and charge. The strength of binding between the porphyrins and Brij 35 depends on the number of binding sites and the solvation shell.     

Oral reconstruction using the peroneal flap

1. Recent studies have indicated that nitric oxide (NO) production in the kidney contributes to the regulation of renal haemodynamics and excretory function. Inhibition of nitric oxide synthase (NOS) reduces renal blood flow by approximately 25% and markedly reduces sodium excretion without reductions in filtered load. In particular, inhibition of NO synthesis markedly suppresses the slope of the arterial pressure-mediated response in sodium excretion. 2. Further studies have shown that constant intrarenal infusion of a NO donor in dogs treated with a NOS inhibitor produced diuretic and natriuretic responses but failed to restore the slope of the pressure-induced natriuretic response. These data indicate that an alteration in intrarenal NO activity, rather than the simple presence of NO during changes in arterial pressure is required for full expression of pressure natriuretic responses. 3. In support of the hypothesis that NO is involved in the mediation of pressure natriuresis, we also recently demonstrated a direct relationship between changes in arterial pressure and urinary excretion rate of sodium as well as nitrate and nitrite (a marker for endogenous NO activity) in the presence of efficient autoregulation of cortical and medullary blood flow. 4. The direct inhibitory actions of NO on tubular sodium reabsorption have also been observed in cultured tubular cells as well as isolated, perfused cortical collecting duct segments. 5. Thus, the collective data suggest that acute changes in arterial pressure induce changes in intrarenal NO production, which may directly alter tubular reabsorptive function to manifest the phenomenon of pressure natriuresis.     

P300 latency: abnormal in sleep apnea with somnolence and idiopathic hypersomnia, but normal in narcolepsy

To evaluate cognitive abnormalities in excessive daytime sleepiness (EDS) using cognitive evoked potentials (P300), and to evaluate if P300 measures differentiate among disorders of EDS, a series of EDS subjects were administered a polysomnogram, auditory and visual P300 testing using 31 scalp electrodes, and a multiple sleep latency test. P300 variables were compared with those of normal subjects. Forty normal subjects ages 16 to 65 years, and 69 EDS patients ages 16 to 65 years were used. Of these, 39 had profound obstructive sleep apnea (OSA, Respiratory Disturbance Index or RDI > 80/h sleep) with severe somnolence (Mean Sleep Latency < 5 min). Twenty-two had idiopathic hypersomnia (IH). Eight had narcolepsy. The normals and the three EDS groups did not differ in age. IH and profound OSA patients had longer visual P300 latency than normals or narcolepsy patients (p < 0.05). (p < 0.05). IH and profound OSA patients had longer auditory P300 latency than normals. They had smaller auditory P300 amplitude than narcolepsy patients. There were visual P300 latency topographic differences between normals and profound OSA patients. In conclusion, IH and profound OSA patients show cognitive evoked potential evidence of cognitive dysfunction. Narcolepsy patients do not show such evidence. Visual P300 latency differentiates among disorders of EDS.     

Intraoperative monitoring of the function of the peroneal nerve in knee joint operations

Operations on the knee are known to be associated with postoperative neurological complications. There is no consensus opinion on the causes of these complications. The aim of the present study was to develop a method for the intraoperative monitoring of the function of the common peroneal nerve. This was done as to identify intraoperative factors that might be responsible for reversible and irreversible neurological deficits. Computer-aided neuromonitoring is based on online digitizing of the surface EMG of the anterior tibial muscle. An algorithm continuously modifies the amplitude to determine the motor threshold. The method described has been used in 18 patients undergoing high tibial osteotomy. In 10 of the 18 patients, the nerve is rendered completely non-excitable after an average tourniquet application time of 59 min. This non-excitability was reversed on release of the tourniquet. In the remaining 8 patients, excitability was maintained throughout the ischaemic period, which did not exceed 60 minutes in any of the cases. Our method enables accurate quantification of the neural function throughout the entire operation, and convincingly documents the influence of ischaemia on peripheral nerve block.     

Thermal latency in radiofrequency ablation

The relative nail producing capacity of different regions within the nail matrix has not been quantified. In order to do this, the number of nail plate cells in the dorsoventral axis of 12 human great toenails was counted at five sites in the longitudinal axis, and compared with direct measurements of nail plate thickness at the same sites. The mean number of nail cells in the nail plate reached a maximum at the lunula, with no further increase along the length of the nail bed. At the mid-point between the proximal tip of the germinal matrix and lunula, mean cell numbers achieved 81% of the value at the lunula. Mean nail thickness was only 90% of its maximum at the lunula, with a further significant increase (P = 0.02) between the lunula and end of the nail bed. These observations suggest that the proximal nail matrix is the main source of nail within the matrix. This is consistent with clinical experience where distal matrix surgery has a low potential for scarring in comparison with proximal matrix surgery. The additional finding of increased nail thickness, but not cell numbers, along the nail bed make it likely that cells within the nail plate change shape as they move distally.     

Tibial and peroneal bypass in severe occlusive disease of the lower extremities

Symptomatic arteriosclerotic occlusive disease involving the femoral and proximal popliteal arteries is currently best treated by reversed autogenous saphenous vein bypass graft. Severe occlusive disease frequently includes the popliteal and/or origin of the trifurcation vessels with reconstitution of one or more of the vessels in the lower leg. We have used distal bypass 97 times in 90 patients during the past decade. There was only one postoperative death in the series in spite of the advanced age and concurrent disease in the majority of the patients. Our indications for operation continue to be relief of pain or salvage of an extremity. We rely on high quality preoperative angiograms for selection of vessels to receive the bypass. The posterior tibial artery was used in 63 of the cases, while the anterior tibial and peroneal were used in 24 and 10 cases, respectively. There were 11 immediate inhospital failures in this series of 97 cases requiring amputation in five. Three additional patients had amputations during the ensuing several months. Of the 85 grafts functioning at the time of discharge from the hospital, 16 or (18.8%) failed during the first years. Grafts that remained patent for one year have a high incidence of long term patency which is in keeping with other reported series.     

Vocal onset latency in the study of question answering.

A study of the adequacy of the vocal response measure in studying question answering among 12 undergraduates showed that vocal answer latencies to yes–no questions closely resembled previously measured buttonpress latencies obtained by the author (1984). On a small number of read-only trials, Ss viewed the phrases "yes," "no," or "don't know" in place of a question. On these trials, the Ss simply recited the phrase on the screen. The resulting "yes" latencies were faster than the others, which did not differ. This result is consistent with the hypothesis that an internal response index is initialized "yes" in yes–no question answering. It is concluded that the vocal onset latency measure and the read-only trial procedure are useful in question answering research. (French abstract) (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Outcome of peroneal neuropathies in patients with systemic malignant disease

BACKGROUND: Peroneal neuropathies in patients with systemic cancer previously have been attributed to weight loss, but to the authors' knowledge other associated conditions have not been assessed, and the outcome of peroneal neuropathies in cancer patients has not been studied. METHODS: A retrospective chart review of patients evaluated at the Mayo Clinic between 1984 and 1993 with systemic malignant disease and a clinical diagnosis of peroneal neuropathy was performed to define factors associated with peroneal neuropathies and to assess outcome. All patients underwent neurologic examination and electromyography. RESULTS: Fifty-eight patients with systemic malignant disease were found to have a peroneal neuropathy. Peroneal neuropathies occurred more often in men (45 patients) than in women (13 patients). The median age of the patients was 70 years. The most common cancers were hematologic (12 patients) and pulmonary (11 patients), followed by tumors of the prostate (8 patients), gastrointestinal tract (7 patients), transitional cell (5 patients), breast (5 patients), and colon (5 patients), as well as sarcomas and melanoma (5 patients). The median time to the diagnosis of peroneal neuropathy after the diagnosis of cancer was 5 months. At the time of diagnosis, 34 patients had severe deficits, 19 had moderate deficits, and 5 had mild deficits. Associated factors included weight loss (occurring in 60% of patients), leg crossing (35% of patients), recent chemotherapy (16% of patients), cutaneous vasculitis (5% of patients), and local metastatic lesions (3% of patients). In nearly 50% of patients, peroneal neuropathy improved (25.9%) or resolved (22.4%). In 39.7% of patients, follow-up was inadequate because death occurred soon after diagnosis. Of the patients with adequate follow-up before death, 80% had either improvement (42.9%) or resolution (37.1%). CONCLUSIONS: For those patients with systemic malignant disease in whom peroneal neuropathy develops, the outcome of the neuropathy is good, with the majority of patients achieving partial or complete resolution.     

Achilles and peroneal tendon injuries in the athlete. An expert's perspective

Peroneal tendonopathy or injuries are not common but may be troubling to the sports enthusiast. Prompt diagnosis and treatment usually result in complete recovery with conservative measures. Biodynamic orthosis with deep heel cups and a long lateral flange extension often are required for return to activity. MR imaging is helpful in difficult, persistent cases to check for ruptures. Surgery is not commonly performed but if required is usually successful in correcting the pathology. Alternative medicine may improve treatment outcomes. Biomechanical functional analysis and attention to training errors is essential in any lower extremity injury or pathology.