On the morphological relations of the Achilles tendon and plantar fascia via the calcaneus: a cadaveric study.

Current treatments of plantar fasciitis are based on the premise that the Achilles tendon (AT) and plantar fascia (PF) are mechanically directly linked, which is an area of debate. The aim of this study was to assess the morphological relationship between the AT and PF. Nineteen cadaveric feet were x-ray imaged, serially sectioned and plastinated for digital image analyses. Measurements of the AT and PF thicknesses and cross-sectional areas (CSA) were performed at their calcaneal insertion. The fiber continuity was histologically assessed in representative subsamples. Strong correlations exist between the CSA of the AT and PF at calcaneal insertion and the CSA of PF's insertional length (r = 0.80), and between the CSAs of AT's and PF's insertional lengths. Further correlations were observed between AT and PF thicknesses (r = 0.62). This close morphological relationship could, however, not be confirmed through x-ray nor complete fiber continuity in histology. This study provides evidence for a morphometric relationship between the AT and PF, which suggests the presence of a functional relationship between these two structures following the biological key idea that the structure determines the function. The observed morphological correlations substantiate the existing mechanical link between the AT and PF via the posterior calcaneus and might explain why calf stretches are a successful treatment option for plantar heel pain.

Stress-controlled decomposition routes in cubic AlCrN films assessed by in-situ high-temperature high-energy grazing incidence transmission X-ray diffraction.

The dependence of decomposition routes on intrinsic microstructure and stress in nanocrystalline transition metal nitrides is not yet fully understood. In this contribution, three Al0.7Cr0.3N thin films with residual stress magnitudes of -3510, -4660 and -5930 MPa in the as-deposited state were in-situ characterized in the range of 25-1100 °C using in-situ synchrotron high-temperature high-energy grazing-incidence-transmission X-ray diffraction and temperature evolutions of phases, coefficients of thermal expansion, structural defects, texture as well as residual, thermal and intrinsic stresses were evaluated. The multi-parameter experimental data indicate a complex intrinsic stress and phase changes governed by a microstructure recovery and phase transformations taking place above the deposition temperature. Though the decomposition temperatures of metastable cubic Al0.7Cr0.3N phase in the range of 698-914 °C are inversely proportional to the magnitudes of deposition temperatures, the decomposition process itself starts at the same stress level of ~-4300 MPa in all three films. This phenomenon indicates that the particular compressive stress level functions as an energy threshold at which the diffusion driven formation of hexagonal Al(Cr)N phase is initiated, provided sufficient temperature is applied. In summary, the unique synchrotron experimental setup indicated that residual stresses play a decisive role in the decomposition routes of nanocrystalline transition metal nitrides.

A field study of a roof bolter canopy air curtain (2nd generation) for respirable coal mine dust control.

A 2nd generation roof bolter canopy air curtain (CAC) design was tested by National Institute for Occupational Safety and Health (NIOSH) at a Midwestern underground coal mine. During the study, the roof bolter never operated downwind of the continuous miner. Using a combination of personal Data Rams (pDR) and gravimetric samplers, the dust control efficiency of the roof bolter CAC was ascertained. Performance evaluation was determined using three methods: (1) comparing roof bolter operator concentrations underneath the CAC to roof bolter concentrations outside the CAC, (2) comparing roof bolter operator concentrations underneath the CAC to the concentrations at the rear of the bolter, and finally, (3) using the gravimetric data directly underneath the CAC to correct roof bolter operator concentrations underneath the CAC and comparing them to the concentrations at the rear of the bolter. Method 1 dust control efficiencies ranged from -53.9% to 60.4%. Method 2 efficiencies ranged from -150.5% to 52.2%, and Method 3 efficiencies ranged from 40.7% to 91%. Reasons for negative and low dust control efficiencies are provided in this paper and include: incorrect sampling locations, large distance between CAC and operator, and contamination of intake air from line curtain. Low dust concentrations encountered during the testing made it difficult to discern whether differences in concentrations were due to the CAC or due to variances inherent in experimental dust measurement. However, the analyses, especially the Method 3 analysis, show that the CAC can be an effective dust control device.

Empirical engineering models for airborne respirable dust capture from water sprays and wet scrubbers.

Airborne respirable coal dust capture by water sprays or wet scrubbers has been studied and developed over many decades as an engineering control to reduce dust exposure in coal mines and combat coal worker pneumoconiosis. Empirical relationships and deterministic models for particular dust capture experiments have previously been devised to show the key parameters involved in airborne coal dust capture. Many of the results from these models show that the significant parameters related to airborne dust capture are water spray pressure, water quantity, water droplet size, relative water droplet-to-dust particle velocity, and total operating air pressure of the scrubber. However, many airborne dust capture efficiency relationships and models developed for particular experiments cannot be readily applied to forecast the dust collection efficiency of different spray and scrubber design configurations, which rely on several key dimensional engineering measures. This study examines engineering measures from previous water spray and wet scrubber experiments conducted by the U.S. National Institute for Occupational Safety and Health (NIOSH) and the U.S. Bureau of Mines (USBM) to develop empirical models for wet collection of airborne dusts. A dimensionless empirical model developed for predicting airborne dust capture efficiency of water sprays and wet scrubbers is presented.

Foam property tests to evaluate the potential for longwall shield dust control.

Tests were conducted to determine properties of four foam agents for their potential use in longwall mining dust control. Foam has been tried in underground mining in the past for dust control and is currently being reconsidered for use in underground coal longwall operations in order to help those operations comply with the Mine Safety and Health Administration's lower coal mine respirable dust standard of 1.5 mg/m3. Foams were generated using two different methods. One method used compressed air and water pressure to generate foam, while the other method used low-pressure air generated by a blower and water pressure using a foam generator developed by the U.S. National Institute for Occupational Safety and Health. Foam property tests, consisting of a foam expansion ratio test and a water drainage test, were conducted to classify foams. Compressed-air-generated foams tended to have low expansion ratios, from 10 to 19, with high water drainage. Blower-air-generated foams had higher foam expansion ratios, from 30 to 60, with lower water drainage. Foams produced within these ranges of expansion ratios are stable and potentially suitable for dust control. The test results eliminated two foam agents for future testing because they had poor expansion ratios. The remaining two foam agents seem to have properties adequate for dust control. These material property tests can be used to classify foams for their potential use in longwall mining dust control.

Respirable dust measured downwind during rock dust application.

The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

Experimental study on foam coverage on simulated longwall roof.

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique's potential for longwall shield dust control.

[Is it possible to enhance our expert knowledge from Wikipedia?]. / Kann Wikipedia unser Fachwissen bereichern?

BACKGROUND: The so-called new media are always a kind of challenge for training supervisors, medical students and doctors-in-training. Especially Wikipedia has a significant position for obtaining important medical information on the internet. Beside many advantages of Wikipedia, there is always the doubt about the correctness of published articles by unknown authors. Therefore the aim of our survey was to investigate the relevance of Wikipedia articles about orthopaedic and traumatological issues in the daily clinical routine. MATERIALS AND METHODS: In September 2013 two different questionnaires about medical issues were given to medical students, resident physicians and one medical specialist. The questioning was about diseases/symptoms, examinations/classifications and conservative therapy/surgery of the department of orthopaedics and traumatology. A total of 211 Wikipedia articles were evaluated. Additionally, the participants gave an subjective estimation about these articles. RESULTS: Overall 134 of 211 separate medical items appeared on Wikipedia. The survey has proven the up-to-dateness of Wikipedia articles and their listing on the first or second position on Google. Wikipedia contains a lot of bibliographical references, high-quality images and video material. Almost half (42,5 %) of all evaluated articles are appropriate for use in medical exams and in the daily clinical work. CONCLUSION: First and foremost young resident physicians, the so-called web 2.0 generation, are using the internet for daily work. Maybe the process of learning is developing and changing at the same time. Wikipedia gives the opportunity for everyone to acquire information for free and all over the place. The collaboration of everyone is necessary to improve the quality of medical issues on Wikipedia.

[How does our specialty present itself on the Internet?]. / Wie präsentiert sich unser Fachgebiet im Internet?

BACKGROUND: The huge amount of information on the internet about orthopaedic and trauma surgical issues is very often unclear and hard to control in reliability, autonomy and expertise. The aim of this work is to evaluate German-speaking internet sites with orthopaedic and trauma surgical contents. MATERIAL AND METHODS: Over a period of two months (from May to June) in 2012 different websites about 20 common orthopaedic and trauma surgical diseases were analysed on the internet by Google search engine. The first ten search results were evaluated for the HON code principles (Health On the Net Foundation). Furthermore there was an evaluation about qualification of the first 50 websites. The best 1,000 placed websites on Google were analysed for the authoritative value: academic, commercial, media, non-medical, physicians, non-profit and miscellaneous. RESULTS: Only 194 from 200 websites could be evaluated by the HON code principles. Overall 188 websites complied the principle of transparency, followed by privacy with 150 sites and authoritative with 134 sites. Only 90 websites give information about financial disclosure. Medical articles of the website Wikipedia appear most frequently. In the second part of this work it is shown that non-profit sites and sites by physicians are the most frequent. The fewest results are given by academic and commercial sites with 93 and 85 online hits. CONCLUSION: In summary, it is shown that most of the websites about medical information have inadequate quality. This statement is in accord with some U. S. American publications. It is clear that Wikipedia has a top-ranking on the internet when it is about medical information. Wikipedia almost achieves all of the HON code principles. It is possible to give better medical online information about orthopaedic and trauma surgical issues published by professionals.

[Total knee arthroplasty in post-traumatic osteoarthritis]. / Knieendoprothetik bei posttraumatischer Arthrose.

BACKGROUND: This study aims to analyse the outcome and the complications after total knee arthroplasty in post-traumatic osteoarthritis in comparison to TKA in patients with degenerative osteoarthritis. PATIENTS AND METHODS: In a period of six years 43 patients with a post-traumatic osteoarthritis were treated with a total knee arthroplasty (group PT). 38 (88 %) patients (age median 55 years, 22 female, 16 male) were investigated clinically and radiologically after an average follow-up time of 2.7 years. The OKS (Oxford Knee Score, max. 48 points), the Knee Society Scores "function" (max. 100 points) and "knee" (max. 100 points) as well as the visual analogue scale (VAS, 0 to 10 points) were recorded preoperatively and at follow-up. For comparison we chose a matched-pair selection of patients with degenerative osteoarthritis and TKA (group DO, age median 63 years, 22 female, 16 male). For statistical analysis we used common parametric tests (Wilcoxon and U test) and a level of significance of 0.05. RESULTS: In 19 patients (50 %) of the group PT the osteoarthritis was caused by a bone injury. Furthermore in 19 patients a meniscal and/or ligamentous injury led to osteoarthritis. Out of all patients of group PT, 10 patients showed a preoperative valgus malalignment higher than 10°. KSS knee and KSS function added up to 76.9 and 84.9 points. So they are significantly less than in the matched group (DO, knee: 86.1; function: 94.4). Similarly, the OKS is significantly less in group PT after follow-up (PT: 32.3; DO: 38.4, p ≤ 0.05) although the preoperative values are equal in both groups. The VAS value decreased significantly in both groups. Initial level of pain was significantly higher in the group DO compared to the group PT. Patients with osteoarthritis after trauma showed complications in 17 cases (^ = 44.7 %) that led to 28 revision operations (^ = 0.7 operations per knee). The group with valgus malalignment had a revision rate of 1.4 operations per knee. In the group DO 8 complications occurred (^ = 21,1 %) that led to 11 revision operations (^=0.3 per knee). The deviation from the "ideal" leg axis could be reduced from 3.8° varus to 1.7° varus in the group DO and from 1.3° valgus auf 1.2° valgus in the group PT. Patients with a preoperative valgus deviation > 10° were reduced from 13.6° (± 3.9°) valgus to 0.5° (± 9.2°) varus. CONCLUSION: Patients after TKA because of post-traumatic osteoarthritis show worse results concerning function and condition compared to patients with degenerative osteoarthritis. Heterogeneous pathogenesis and high rates of revision operations underline the complexity of this group of patients. The treatment has to be adjusted to the patient's requirements as well to the pathoanatomy.

[Reimplantation of a hip prosthesis in patients with an infected resection arthroplasty]. / Die Reimplantation eines künstlichen Hüftgelenkes bei septischer Girdlestone-Situation.

AIM: Resection arthroplasty is an accepted surgical option to treat severe late periprosthetic infections. However, it is known that one has to consider that a persistence of infection is very often combined with a permanent fistula in approximately 10 % of the patients. In particular, the occurrence of a fistula and pain caused by the persistent infection is followed by a considerable reduction of the quality of life of these patients. We have analysed the effort and complications of treatment and the change of pain and function of these patients. METHOD: In this study 11 patients (average age 68 years) with a Girdlestone situation and persistent infection with an average duration of 33 months were successfully treated by a multiple stage surgical therapy plan which included a radical surgical revision of the infection, stepwise leg lengthening and subsequent reimplantation. In all cases surgical revision of the infection was supported by both systemic and local (antibiotic-loaded cement spacer) antibiotic therapy. The choice of implants followed the general recommendations for revision hip arthroplasty. RESULTS: The mean follow-up after reimplantation was 16 months (min 4, max 24). We observed an average improvement of the Harris hip score from 27.7 points at the beginning of the therapy to 72.5 points at the end of the follow-up. None of the patients had suffered from a reinfection at the end of the follow-up. We observed no surgically related mortality. Surgical complications including spacer dislocations and implant dislocation were seen. The leg length discrepancy could be decreased from an average of 6.8 cm to 1 cm without the occurrence of a neurological deficit. CONCLUSION: The reimplantation of a hip prosthesis in cases of infected Girdlestone situations is complex, it can, however, offer the prospect of a marked increase in function and less pain for these patients.

[Minimally invasive unicondylar knee arthroplasty with simultaneous ACL reconstruction : treatment of medial compartment osteoarthritis and cruciate ligament defect]. / Mediale Gonarthrosen mit Kreuzbanddefekt : Kombinierte Versorgung mittels unikondylärer Endoprothese und additivem Kreuzbandersatz.

BACKGROUND: Low postoperative pain level, decreased length of hospital stay and accelerated rehabilitation are the major benefits of unicondylar knee arthroplasty. Especially in comparably young, not yet retired and still active patients with an isolated medial gonarthrosis, these prostheses offer many advantages. However, one important requirement to be treated with such implants is a well functioning stability system of the muscles and ligaments. Thus in patients with degenerated or destroyed anterior cruciate ligaments it is contraindicated to use this method. In order to still take advantage of this therapy for treatment of isolated arthrosis, reestablishment of the proprioceptive structures through simultaneous or staged ACL reconstruction is mandatory. PATIENTS AND METHODS: Pursuing this goal we performed unicondylar knee arthroplasty with simultaneous ACL reconstruction on eligible patients. Between 2003 and 2006 we treated 32 knees with this combined surgery and followed them for a mean of 31 months (range: 10-38). RESULTS: The mean Knee Society Score significantly improved from 83.2 (44-103) to 167.6 (145-177) at a mean follow-up of 31 months (10-38). CONCLUSIONS: Preliminary results of this short-term follow-up are promising. Especially the predominant number of patients who were able to return to work soon after rehabilitation and the significantly improved score postoperatively reflect the benefits of this prosthesis system in select patients. However, long-term follow-up and larger case numbers are necessary to confirm these encouraging results in the future.

[Reconstruction of the ligamentum cruciatum anterius during the performance of unicondylar knee arthroplasty by minimally invasive surgery. A salvage procedure for monocondylar arthrosis and downfall of the anterior cruciate ligament]. / Additive Kreuzbandplastik bei der Implantation von unikondylären Endoprothesen mittels Miniarthrotomie. Eine Lösungsmöglichkeit bei unilateralen Arthrosen mit Kreuzbandverlust.

Opinions differ on unicompartmental knee replacement for treatment of unicompartmental ostearthritis of the knee. There is general agreement that well-functioning cruciate ligaments are necessary if use of this prosthesis is to be successful. Especially for younger people who are still working and who have advanced medial arthritis and lacking or inadequate anterior cruciate ligament, this therapy has its limitations. To exploit the advantages of unicondylar replacement in such patients, we combined this joint replacement operation with reconstruction of the anterior cruciate ligament using the semitendinosus/gracilis tendon and applying a transfix technique in 7 cases. The mean Knee Society Score was recorded preoperatively and after 12 and 28 months of follow-up. Long-term results are not yet available, but after this operation method average Knee Society Scores of 164.1 were recorded at 28 months, and all these patients were able to return to work after their rehabilitation. Thus, the short-term follow-up documents the efficacity of the treatment and benefit to the patients.

[Revision possibilities after failed unicompartmental knee arthroplasty--an analysis of 116 revisions]. / Revisionsmöglichkeiten nach Problemen mit unikondylären Endoprothesen--Eine Analyse von 116 Operationen.

AIM: A major advantage of the unicompartmental knee arthroplasty (UKA) is the quick rehabilitation, small traumatisation of tissue and the mostly uncomplicated revision to a total knee arthroplasty. The aim of the study is to examine whether the conversion to the total endoprosthesis, as is frequently is recommended at present in cases of defect of the sleigh system, is always necessary or whether a revision can have good chances of success with use of the unicondylar system under certain conditions. METHOD: 116 revisions were studied after unicompartmental knee arthroplasty at the first appearance of problems and during the follow-up of 45 months (range: 10-86 months) using the Knee Society Score and analyses of the various additional procedures as well as the anterior cruciate ligament substitute, the correction of slope etc. Revisions, with exchange of components or a conversion to a total arthroplasty, were included. RESULTS: In 60.3 % of all cases a revision could be performed within the unicompartmental knee system, with a mean score of 167.4 (range: 144-173). The outcome score corresponded to the outcome of primary UKA implantations and to conversion operations to total endoprosthesis in the literature (p < 0.05 Wilcoxon test). CONCLUSION: Under critical contemplation of the low case number and this short- to medium-term examination, individual revision solutions seem to have their entitlement within the unicondylar system as also do conversion operations to the TKA. Long-term results and larger case numbers are absolutely necessary prior to further judgment.

[Osteoporosis--a neglected issue in orthopaedics? Results of a survey amongst German orthopaedic surgeons]. / Osteoporose -- Ein Stiefkind der Orthopädie? Ergebnisse einer Befragung deutscher Orthopäden.

AIM: Patients with fragility fractures have a significantly increased risk of sustaining additional fractures. Therefore one should consider avoidance of further fractures as the primary treatment principle. Since orthopaedic surgeons manage most of fragility fractures, but might not be well attuned to osteoporosis itself, it was the aim of the Bone and Joint Decade (BJD) and the International Osteoporosis Foundation (IOF) to survey orthopaedic surgeons in order to assess their knowledge of prevention, diagnosis, and treatment of osteoporosis. MATERIAL AND METHODS: The multinational survey questionnaire was developed by a working group of national project co-ordinators in France, Germany, Italy, Spain, the United Kingdom, and New Zealand and based to some extent on an American survey. Following translation into the national language it was distributed in 2002 to the members of the orthopaedic societies to assess the management of prevention, diagnosis, and therapy of osteoporosis and fragility fractures, comparing both different health-care systems and different working environments. 5 700 questionnaires were distributed in Germany with a 20 percent response rate. RESULTS: As the main result of the German survey -- independent of the working environment -- a substantial deficit concerning training and knowledge about the management of prevention, diagnosis, and treatment of osteoporosis and fragility fractures was seen. In addition, the majority of participants requested educational opportunities to become qualified for a better disease control. CONCLUSION: In order to satisfy the increasing need for adequate management of prevention, diagnosis, and therapy of osteoporosis and fragility fractures, structured educational opportunities have to be offered to the German orthopaedic community. In the mean time first steps have been initiated: training courses to qualify as "Osteologe DVO" and the "White Book Osteoporosis", which was initiated by BJD and IOF and developed by several German medical societies and patient organisations it is based on the German DVO guidelines providing an evidence-based and structured overview concerning all relevant aspects of osteoporosis and fragility fractures.

[Wristing -- a new opportunity in digital migration analysis of uncemented total hip arthroplasty]. / Wristing -- eine neue Möglichkeit für Digitale Migrationsmessung in der Hüftendoprothetik.

AIM: The aim of this study was to evaluate a computer program (Wristing) for digital migration analysis in hip endoprotheses and to assess the most accurate landmarks in hip-alone radiographs. METHOD: Conventional radiographs of 52 patients with a minimum follow-up period of seven years and five consecutive radiographs were digitised and different landmarks were compared. The parameters with the greatest accuracy were analysed to calculate inter- and intra-observer variability in 30 radiographs. Digital and manual measurement techniques were compared with each other. RESULTS: The obtained accuracy (95 % confidence interval) was 1.7 to 2.2 mm and 2.8 degrees to 3.2 degrees for the most accurate landmarks. The intra-observer variability was 0.12-0.3 mm; 0.28 degrees and the inter-observer variability ranged from 0.14 to 0.45 mm and 0.5 degrees to 0.53 degrees . In comparison to the migration measurement with pencil and ruler (precision: 0.24-0.67 mm; 0.57-0.74 degrees ) the new software (precision: 0.12-0.3 mm; 0.28 degrees ) was associated with a superior accuracy (t test: p < 0.001). CONCLUSION: With the program "Wristing" migration in hip-alone radiographs could be recorded with high precision. The integrated sketch, zooming and the current possibility of comparing radiographs and patient data with previous follow-ups and examples leads to a high inter- and intra-observer accuracy and is very useful in day-to-day clinical practice.

[Multimedia preoperative patient information]. / Multimediale Patientenaufklärung in der Klinik.

Due to heavy workloads and shortage of staff, doctors often find it difficult to explain operations to their patients with the legally required detail and timing (in Germany, 24 h preop). This is however mandatory for obtaining informed consent. We developed a computer program that generates films explaining 24 common orthopedic operations and blood transfusion. They explain the operation, early postoperative phase, and benefits and risks to the patient. At our clinic, this program is used in daily routine and precedes the actual doctor-patient conversation for informed consent. We asked 300 patients about their satisfaction with the newly developed program. The multimedia presentation gives the patient more time, enough detail and clarity, and the chance to repeat parts of the film. For the doctor, it saves time. The time gap required in Germany between explanation and operation is thus easily adhered to. In case of legal problems, the film can be used for evidence. The use of this multimedia presentation to help in getting informed consent is improving workflow considerably.

Correcting tritium concentrations in water vapor monitored with silica gel.

A correction is needed to calculate the activity concentration of airborne tritium oxide when dried silica gel is used as the collector. A tracer study using tritiated water with silica gel showed that the concentration of tritium in desorbed water is lower than that in adsorbed water by a fraction that increases with the amount of adsorbed water. The hypothesis was tested that adsorbed tritiated water is diluted by isotopic exchange with both non-tritiated water and hydroxyl groups within the silica gel matrix. The extent of dilution was measured from 4% to 14% adsorbed water, which is typical of moisture on field collectors for monitoring airborne tritium oxide. For this range of percent adsorbed water, the inferred percent exchangeable water in the silica gel under study was 6.3 +/- 0.1%. This value compares to the silica gel weight loss of 5.3% after heating to 1,050 degrees C. An explanation of the difference between 6.3% and 5.3% is proposed. The contribution of the HTO/H2O vapor pressure isotope effect was considered in calculating isotopic exchange. A curve is presented for correcting the measured tritium concentration in the distillate from the silica gel as a function of the amount of adsorbed water. The tritium tracer procedure is recommended for determining the percent exchangeable water in other silica gels to correct tritium measurements of water vapor collected by them.

[Results of routine intraoperative cholangiography]. / Ergebnisse der intraoperativen Routinecholangiographie.

Most bile duct injuries result from an incorrect interpretation of bile duct anatomy. In 500 laparoscopic cholecystectomies we used a modified technique of cholecystcholangiography. This method is very easy and needs only 5 minutes. We found variants of bile duct anatomy in 74 cases and occult bile duct stones in 20 patients. We recommend this method which decreases the risk of bile duct injuries and gives the opportunity to approximate the golden standard of conventional cholecystectomy.