Changes of density distribution of the subchondral bone plate after supramalleolar osteotomy for valgus ankle osteoarthritis

CT‐osteoabsorptiometry (CT‐OAM) has been used to visualize subchondral bone plate density distribution regarding to its mineralization. The purpose of this study was to display and analyze the density distribution of the subchondral bone plate before and after supramalleolar realignment osteotomies. We retrospectively analysed pre‐ and postoperative CT images of nine consecutive patients with post‐traumatic unilateral valgus ankle OA. The distribution charts of CT‐OAM scans were quantitatively analyzed for subchondral bone plate density distribution. VAS for pain and the Tegner activity scale were used to assess clinical outcome. At a mean follow‐up of 20 ± 5.6 months (range 13–27), we observed a significant pre‐ to postoperative decrease of the mean high‐density area ratio in tibia (lateral and posterior area) (p ≤ 0.05) and the talus (lateral area) (p ≤ 0.05). Pairwise comparison between the pre‐ and postoperative mineralization at the articular surface showed a significant decrease of the high‐density area ratio for the tibia and the talus. The VAS decreased from 6.2 ± 0.9 pre‐ to 2.8 ± 0.9 postoperatively (p = 0.027), and the Tegner score inclined from 4.5 ± 1.1 preoperatively to 5.3 ± 0.7 after surgery (p = 0.082). The tibial and talar subchondral bone plate density, regarding to its mineralization, decreased after supramalleolar medial closing wedge osteotomy in patients with valgus ankle OA. The results of this study suggest that realignment surgery may decrease peak bone density areas corresponding to the alignment correction and contribute to a homogenization of the subchondral bone plate mineralization. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1356–1361, 2014. Level of evidence Level IV, Case series.     

Conversion between noise exposure indicators Leq24h, LDay, LEvening, LNight, Ldn and Lden: Principles and practical guidance

This article presents empirically derived conversion rules between the environmental noise exposure metrics Leq24 h, LDay, LEvening, LNight, Ldn, and Lden for the noise sources road, rail and air traffic. It caters to researchers that need to estimate the value of one (unknown) noise metric from the value of another (known) metric, e.g. in the scope of epidemiological meta-analyses or systematic reviews, when results from different studies are pooled and need to be related to one common exposure metric. Conversion terms are derived using two empirical methods a) based on analyzing the diurnal variation of traffic, and b) by analyzing differences between calculated noise exposure metrics. For a) we collected and analyzed diurnal traffic share data from European and US airports as well as data on the diurnal variation of traffic from roads in several European countries and from railway lines in Switzerland which were derived from counting stations and official records. For b) we calculated differences between noise metrics in over 50'000 stratified randomly sampled dwellings in Switzerland. As a result of this exercise, conversion terms, including uncertainty estimates, are systematically tabulated for all variants of the target metrics. Guidance as to the practical applicability of the proposed conversions in different contexts is provided, and limitations of their use are discussed.     

Ausfall der FAEP-Wellen I und II während tiefer Hypotension

For surgical removal of a malignant choroid melanoma, it is necessary to reduce systolic blood pressure to around 50–60?mmHg in order to prevent choroidal haemorrhages. However, blood pressure reduction is associated with the risk of cerebral ischaemia. We report a patient with a malignant choroid melanoma in whom waves?I and II of the brainstem auditory evoked potentials (BAEP) disappeared during surgery under controlled arterial hypotension and hypothermia (31.1°?C). The waves could be recorded again immediately after the mean arterial pressure was increased from 48 to 77?mmHg. The oesophageal temperature had dropped by 0.3°?C at this time. The 2-channel electroencephalogram (EEG) showed no irregularities during this time period. A bilateral, reversible, apparently blood-pressure-dependent loss of waves I and II during arterial hypotension despite a normal EEG has to our knowledge not been previously described in the literature. The isolated loss of waves I and II with maintenance of waves III, IV, and V is unusual. The literature contains reports of acoustic neurinoma patients in whom only wave V could be recorded. This is regarded as an indication of continued impulse conduction despite the loss of waves I to IV. Others have observed a patient with temporary and reversible loss of BAEP wave I due to vasospasm of the internal auditory artery that apparently occurred during or shortly after manipulation of the internal auditory meatus. Assuming anatomic peculiarities in the blood supply to the generators of the BAEP waves, a stenosis of the basilar artery could be considered as the cause of the bilateral reversible loss of waves I and II. Another potential source could be the induced hypothermia, but this does not seem very likely because the patient's temperature was 0.3°?C lower at the return of the waves than at their loss.     

VACTERL or MURCS association in a girl with neurenteric cyst and identical thoracic malformations in the father: a case of gonosomal mosaicism?

We report on a female infant with lethal congenital malformations including extreme hydrocephalus due to aqueductal stenosis, vertebral segmentation anomalies, fused costae, anal atresia, renal dysplasia, and bicornuate uterus with a double blind vagina. The VACTERL and the MURCS associations are possible diagnoses. Her father had a neurenteric cyst in infancy. He has identical vertebral and costal malformations as his daughter but is otherwise healthy. The possibility of dominant inheritance with gonosomal mosaicism in the father is discussed.