High (36)Cl/Cl ratios in Chernobyl groundwater.

After the explosion of the Chernobyl Nuclear Power Plant in April 1986, contaminated material was buried in shallow trenches within the exclusion zone. A (90)Sr plume was evidenced downgradient of one of these trenches, trench T22. Due to its conservative properties, (36)Cl is investigated here as a potential tracer to determine the maximal extent of the contamination plume from the trench in groundwater. (36)Cl/Cl ratios measured in groundwater, trench soil water and leaf leachates are 1-5 orders of magnitude higher than the theoretical natural (36)Cl/Cl ratio. This contamination occurred after the Chernobyl explosion and currently persists. Trench T22 acts as an obvious modern point source of (36)Cl, however other sources have to be involved to explain such contamination. (36)Cl contamination of groundwater can be explained by dilution of trench soil water by uncontaminated water (rainwater or deep groundwater). With a plume extending further than that of (90)Sr, radionuclide which is impacted by retention and decay processes, (36)Cl can be considered as a suitable tracer of contamination from the trench in groundwater provided that modern release processes of (36)Cl from trench soil are better characterized.

The volar portal in wrist arthroscopy.

Wrist arthroscopy is not only a diagnostic tool; it has also developed into a valuable treatment alternative for several wrist disorders. All of the standard portals are dorsally located, leaving the dorsal sector of the radiocarpal and midcarpal joint partially invisible. A volar portal has been developed through the bed of the flexor carpi radialis tendon, thus expanding the therapeutic possibilities. We report our personal experience with the use of a volar portal in 28 of 206 (14%) wrist arthroscopies. No technical problems or neurovascular complications were encountered. We think the standardized approach as described is valuable and safe.

Is there still a place for arthrodesis in the surgical treatment of basal joint osteoarthritis of the thumb?

Despite the obvious success of arthroplasty trapeziectomy with or without interposition and prosthesis--in the treatment for trapeziometacarpal osteoarthritis, one may question the value of an arthrodesis in particular situations. In most reported series the outcome is reasonably successful, but when comparing the results of arthrodesis with arthroplasty, there is convincing evidence that the latter gives better outcomes. Considering the overall complication rate, and more specifically the incidence of nonunion after trapeziometacarpal fusion, it can be reasonably concluded that the latter should be reserved for specific indications.

Carpal tunnel syndrome in children.

Carpal tunnel syndrome is a condition rarely encountered in infants. We describe five patients with nine involved hands. One was reported earlier. In three cases the cause of carpal tunnel syndrome is a storage disease: one girl with mucolipidosis type III and a boy and a girl with mucopolysaccharidosis type I. The fourth case is a girl presenting with unilateral macrodactyly of the right third and fourth digits. The last case involves a boy with familial carpal tunnel syndrome. We briefly discuss these patients and review the literature since 1989.

Carpal tunnel syndrome in children.

Carpal tunnel syndrome (CTS) is rarely seen in children. A literature search in 1989 revealed 52 published cases. The authors review 163 additional cases that were published since that date. The majority of these cases were related with a genetic condition. The most common aetiology was lysosomal storage disease: mucopolysaccharidoses (MPS) in 95 and mucolipidoses (ML) in 22. In CTS secondary to MPS, clinical signs typical of adult CTS are rarely seen, and difficulty with fine motor tasks is the most frequent finding. CTS in MPS does not seem to be prevented by bone marrow transplantation, the usual treatment for the condition. CTS is probably due to a combination of excessive lysosomal storage in the connective tissue of the flexor retinaculum and a distorted anatomy because of underlying bone dysplasia. Mucolipidoses come next in the aetiology, with essentially similar symptoms. The authors found in the literature 11 cases of primary familial CTS, a condition which presents as an inheritable disorder of connective tissue mediated by an autosomal dominant gene; the symptoms may be more typical in some cases, but are more similar to MPS in others. A case with self-mutilation has been reported. Hereditary neuropathy with liability to pressure palsies (HNPP) is a rare autosomal dominant condition characterised by episodes of decreased sensation or palsies after slight traction or pressure on peripheral nerves; it may also give symptoms of CTS. Schwartz-Jampel syndrome (SJS), another genetic disorder with autosomal recessive skeletal dysplasia, is characterised by varying degrees of myotonia and chondrodysplasia; it has also been noted associated with CTS in a child. Melorrheostosis and Leri's syndrome have also been noted in children with CTS, as well as Déjerine-Sottas syndrome and Weill-Marchesani syndrome. Among non-genetic causes of CTS in children, idiopathic cases with children onset have been reported, usually but not always related with thickening of the transverse carpal ligament. Intensive sports practice has been reported as an aetiological factor in several cases of childhood CTS. Nerve territory oriented macrodactily, a benign localised form of gigantism, is another unusual cause of CTS in children, as are fibrolipomas of the median nerve or intraneural perineuroma or haemangioma of the median nerve. Acute cases have been reported in children with haemophilia, secondary to local bleeding. Another local cause is a musculotendinous malformation of the palmaris longus, the flexor digitorum superficialis, the flexor carpi radialis brevis (a supernumerary muscle), the first lumbricalis or the palmaris brevis. Isolated cases of childhood CTS have also been reported in Klippel-Trenaunay syndrome, in Poland's syndrome and in scleroderma. Finally, several cases have been noted following trauma, most often related with epiphysiolysis of the distal radius. Immediate reduction has cleared the problem in most cases, but exploration of the median nerve should be considered otherwise, and also in cases with delayed occurrence of symptoms. Overall 145 of the 163 reviewed cases have undergone open carpal tunnel release. Childhood CTS often has an unusual presentation, with modest complaints and children are often too young to communicate their problem. In CTS with specific aetiologies such as storage disease, the symptoms may be masked by the skeletal dysplasia and joint stiffness. Every child with even mild symptoms must be thoroughly examined and a family history must be taken. Children with storage disease may benefit from early clinical and electrophysiological screening before they develop obvious clinical signs.

Deriving TDS values in coarse sediments from long normal and electromagnetic logs.

This paper presents an empirical relationship of quantitatively linked electromagnetic (EM) borehole recordings of the total dissolved solids (TDS) in pore water in the Quaternary deposits of the Belgian coastal plain. First, the long normal (LN) logs are linked to EM logs, then the already developed relationships between LN resistivity measurements and the TDS values are rewritten for EM recordings. The main parameter in these equations is the formation factor, which is derived from ground water analyses and LN logs through Archie's law. The EM recording has several advantages compared to the LN logs. The EM analysis allows measuring in PVC-cased wells and is not hindered by the invasion zone around the well. Furthermore, it has a high vertical resolution. LN logs can be measured only once, after drilling a well; EM recordings can be repeated several times in monitoring wells, which allows the gathering of time-dependent data over a complete vertical cross section. Such data could be obtained with LN logs only in wells with screens over the full-depth interval, which causes a hydraulic short circuit. This short circuit can result in a large artificial flow through the well between different levels, resulting in a salinity profile, which is no longer representative for the studied site. Remediation against short circuiting is a reduction of the screened interval, which strongly reduces the gathered information. The application of the derived equations is one of setting up a monitoring network along the Belgian coast to monitor the trend in salinity levels and comparing present salinity levels with older LN recordings to investigate the salinity changes in the last 30 years. Deep wells already present in the Belgiancoastal plain can then be used to monitor both the fresh water head changes and the salt water evolution. The technique has also been used for parameter identification for which real concentration measurements were needed.