Rapidly progressive coal workers' pneumoconiosis in the United States: geographic clustering and other factors.

BACKGROUND: Despite significant progress made in reducing dust exposures in underground coal miners in the United States, severe cases of coal workers' pneumoconiosis (CWP), including progressive massive fibrosis (PMF), continue to occur among coal miners. AIMS: To identify US miners with rapidly progressive CWP and to describe their geographic distribution and associated risk factors. METHODS: Radiographic evidence of disease progression was evaluated for underground coal miners examined through US federal chest radiograph surveillance programmes from 1996 to 2002. A case of rapidly progressive CWP was defined as the development of PMF and/or an increase in small opacity profusion greater than one subcategory over five years. County based prevalences were derived for both CWP and rapidly progressive cases. RESULTS: A total of 886 cases of CWP were identified among 29 521 miners examined from 1996 to 2002. Among the subset of 783 miners with CWP for whom progression could be evaluated, 277 (35.4%) were cases of rapidly progressive CWP, including 41 with PMF. Miners with rapidly progressive CWP were younger than miners without rapid progression, were more likely to have worked in smaller mines (<50 employees), and also reported longer mean tenure in jobs involving work at the face of the mine (in contrast to other underground mining jobs), but did not differ with respect to mean underground tenure. There was a clear tendency for the proportion of cases of rapidly progressive CWP to be higher in eastern Kentucky, and western Virginia. CONCLUSIONS: Cases of rapidly progressive CWP can be regarded as sentinel health events, indicating inadequate prevention measures in specific regions. Such events should prompt investigations to identify causal factors and initiate appropriate additional measures to prevent further disease.

Operative treatment of supracondylar fractures of the humerus in children. The consequences of pin placement.

BACKGROUND: The commonly accepted treatment of displaced supracondylar fractures of the humerus in children is fracture reduction and percutaneous pin fixation; however, there is controversy about the optimal placement of the pins. A crossed-pin configuration is believed to be mechanically more stable than lateral pins alone; however, the ulnar nerve can be injured with the use of a medial pin. It has not been proved that the added stability of a medial pin is clinically necessary since, in young children, pin fixation is always augmented with immobilization in a splint or cast. METHODS: We retrospectively reviewed the results of reduction and Kirschner wire fixation of 345 extension-type supracondylar fractures in children. Maintenance of fracture reduction and evidence of ulnar nerve injury were evaluated in relation to pin configuration and fracture pattern. Of 141 children who had a Gartland type-2 fracture (a partially intact posterior cortex), seventy-four were treated with lateral pins only and sixty-seven were treated with crossed pins. Of 204 children who had a Gartland type-3 (unstable) fracture, fifty-one were treated with lateral pins only and 153 were treated with crossed pins. RESULTS: There was no difference with regard to maintenance of fracture reduction, as seen on anteroposterior and lateral radiographs, between the crossed pins and the lateral pins. The configuration of the pins did not affect the maintenance of reduction of either the Gartland type-2 fractures or the Gartland type-3 fractures. Ulnar nerve injury was not seen in the 125 patients in whom only lateral pins were used. The use of a medial pin was associated with ulnar nerve injury in 4% (six) of 149 patients in whom the pin was applied without hyperflexion of the elbow and in 15% (eleven) of seventy-one in whom the medial pin was applied with the elbow hyperflexed. Two years after the pinning, one of the seventeen children with ulnar nerve injury had persistent motor weakness and a sensory deficit. CONCLUSIONS: Fixation with only lateral pins is safe and effective for both Gartland type-2 and Gartland type-3 (unstable) supracondylar fractures of the humerus in children. The use of only lateral pins prevents iatrogenic injury to the ulnar nerve. On the basis of our findings, we do not recommend the routine use of crossed pins in the treatment of supracondylar fractures of the humerus in children. If a medial pin is used, the elbow should not be hyperflexed during its insertion.

Pulmonary inflammation and crystalline silica in respirable coal mine dust: dose-response.

This study describes the quantitative relationships between early pulmonary responses and the estimated lung-burden or cumulative exposure of respirable-quartz or coal mine dust. Data from a previous bronchoalveolar lavage (BAL) study in coal miners (n = 20) and nonminers (n = 16) were used including cell counts of alveolar macrophages (AMs) and polymorphonuclear leukocytes (PMNs), and the antioxidant superoxide dismutase (SOD) levels. Miners' individual working lifetime particulate exposures were estimated from work histories and mine air sampling data, and quartz lung-burdens were estimated using a lung dosimetry model. Results show that quartz, as either cumulative exposure or estimated lung-burden, was a highly statistically significant predictor of PMN response (P < 0.0001); however cumulative coal dust exposure did not significantly add to the prediction of PMNs (P = 0.2) above that predicted by cumulative quartz exposure (P < 0.0001). Despite the small study size, radiographic category was also significantly related to increasing levels of both PMNs and quartz lung burden (P-values < 0.04). SOD in BAL fluid rose linearly with quartz lung burden (P < 0.01), but AM count in BAL fluid did not (P > 0.4). This study demonstrates dose-response relationships between respirable crystalline silica in coal mine dust and pulmonary inflammation, antioxidant production, and radiographic small opacities.

Complications of posterior iliac crest bone grafting in spine surgery in children.

STUDY DESIGN: The perioperative and postoperative complications associated with harvesting posterior iliac crest bone graft in children were reviewed. A retrospective study was performed and a questionnaire interview conducted. OBJECTIVES: To determine the morbidity associated with posterior iliac crest bone graft in children. SUMMARY OF BACKGROUND DATA: Iliac crest bone is commonly used as a source of bone graft in spine surgery. Although there are multiple reports of complications in adults, there are no reports in children. METHODS: A retrospective chart review was performed of 214 consecutive children who underwent spinal fusion with posterior iliac crest bone graft from 1990 through 1996. An interview was conducted of 87 patients with normal mental status, predominantly those with idiopathic scoliosis with a minimum of 2 years' follow-up (mean, 55 months). RESULTS: The review showed one (0.5%) instance of arterial injury in the sciatic notch. Two (1%) patients had infections, both of which resolved with a single irrigation and débridement. There was one documented instance of sacroiliac penetration that did not cause clinical problems. The chart review showed three (1.4%) instances of continued pain and one (0.5%) of numbness. By contrast to the few reports of pain in the chart review, responses to an interview of 87 patients showed 21 (24%) children reporting pain at the iliac crest site, with 13 (15%) reporting problems with daily activities. The self-reported pain, on a scale of 1 to 10, ranged from 1 to 10 with a mean of 4. Nonsteroidal anti-inflammatory drugs (NSAIDS) were taken by eight (9%) children for pain at the bone graft site. Five (6%) reported skin irritation, and 18 (20%) mentioned numbness surrounding the scar. CONCLUSION: The perioperative rate of complications in iliac crest bone grafting in children is low (2%). The complication of pain (24%) and pain that is severe enough to interfere with daily activity (15%) is significant at a mean follow-up of more than 4 years. The true extent of pain and numbness after posterior iliac crest bone grafting in children was severely underreported in the medical records and may be underrecognized.

Views on local data management in cancer clinical trials.

The randomized clinical trial is the ultimate method of establishing the value of any new cancer treatment, but the percentage of patients with cancer in the UK who are included in clinical trials of any sort is in single figures. The reasons for this low figure include both patient and clinician factors. The extra work involved in trials is cited repeatedly by clinicians as the main reason for not entering patients into cancer clinical trials. This paper discusses how the provision of local data management could be one important way to improve recruitment into and to ensure the smooth running of clinical trials.

Molecular contingencies: reinforcement probability.

Pigeons obtained food by responding in a discrete-trials two-choice probability-learning experiment involving temporal stimuli. A given response alternative, a left- or right-key peck, had 11 associated reinforcement probabilities within each session. Reinforcement probability for a choice was an increasing or a decreasing function of the time interval immediately preceding the choice. The 11 equiprobable temporal stimuli ranged from 1 to 11 sec in 1-sec classes. Preference tended to deviate from probability matching in the direction of maximizing; i.e., the percentage of choices of the preferred response alternative tended to exceed the probability of reinforcement for that alternative. This result was qualitatively consistent with probability-learning experiments using visual stimuli. The result is consistent with a molecular analysis of operant behavior and poses a difficulty for molar theories holding that local variations in reinforcement probability may safely be disregarded in the analysis of behavior maintained by operant paradigms.

Use of a hybrid external fixator for a severely comminuted juxta-articular fracture of the distal humerus.

Severely comminuted, juxta-articular fractures present a difficult management dilemma for orthopaedic surgeons. Recently, hybrid external fixators have been used for treatment of such fractures in the lower extremity, particularly in the tibial plateau and the tibial plafond. The same technique may be applied to the upper extremity with gratifying results. This technique has the advantage of minimal dissection while restoring limb alignment and permitting immediate joint motion. The proximity of neurovascular structures to the humerus requires careful attention to anatomic detail when placing such a fixator.

Supraventricular tachycardia complicating the use of prostaglandin vaginal gel for induction of labour.

We present a case of a 31-year-old female patient who developed a supraventricular tachycardia and haemodynamic instability secondary to the use of vaginal prostaglandin E(2)gel for induction of labour. This complication occurred despite the patient's young age, absence of pre-existing ischaemia or coronary artery spasm, and the use of vaginal, rather than intravenous or intramyometrial prostaglandin. Physicians should be aware that serious cardiovascular complications can occur with vaginal prostaglandin E(2)therapy even in the absence of pre-existing risk factors.

A simplified valgus osteotomy of the proximal femur in children.

Valgus osteotomy of the hip is required in a number of orthopedic conditions in children. We present a simplified valgus osteotomy in which a dynamic compression plate is used. This technique has the advantages of using easily available equipment, requiring only one osteotomy, and providing immediate rigid fixation while not violating the proximal femoral physis. We have used this simplified technique for valgus osteotomy in six hips in four children with excellent fixation, good maintenance of correction, and no complications.

Respiratory health services reported by U.S. mining facilities in the National Occupational Health Survey of Mining (1984-1989).

This report describes the involvement of mine management personnel at U.S. mines in providing environmental and medical services related to respiratory health. The data were obtained by means of a questionnaire that was administered to mine management personnel at 491 mines and mills during May 1984 to August 1989. The data indicate that 62% of U.S. miners worked at facilities that provided at least a portion of workers with chest X-rays, and 41% worked at facilities that provided at least a portion of workers with pulmonary function tests. Eighty-five percent of miners worked at facilities in which the company required a medical examination of all new employees; the majority were required by company policy to have a medical examination before returning to work after an illness. However, only 2% of miners were required by company policy to have an exit medical examination when their employment ended. This report underscores the need for respiratory health to remain a primary concern of all persons who provide occupational health services to miners.

Surveillance of respirable crystalline silica dust using OSHA compliance data (1979-1995).

BACKGROUND: The objective of this work was to estimate the percentage of workers by industry that are exposed to defined concentrations of respirable crystalline silica dust. METHODS: An algorithm was used to estimate the percentage of total workers exposed to crystalline silica in 1993 at concentrations of at least 1, 2, 5, and 10 times the National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) of 0.05 mg/m3. Respirable crystalline silica air sampling data from regulatory compliance inspections performed by the Occupational Safety and Health Administration (OSHA), for the years 1979-1995, and recorded in the Integrated Management Information System (IMIS) were used to estimate exposures. Therefore, this work does not include industries such as mining and agriculture that are not covered by OSHA. The estimates are stratified by Standard Industrial Classification (SIC) codes. RESULTS: This work found that some of the highest respirable crystalline silica dust concentrations occurred in construction (masonry, heavy construction, and painting), iron and steel foundries (casting), and in metal services (sandblasting, grinding, or buffing of metal parts). It was found that 1.8% (13,800 workers) of the workers in SIC 174--Masonry, Stonework, Tile Setting, and Plastering--were exposed to at least 10 times the NIOSH REL. For SIC 162--Heavy Construction, Except Highway and Street Construction--this number is 1.3% (6,300 workers). SIC 172--Painting and Paper Hanging--which includes construction workers involved in sandblasting was found to have 1.9% (3,000 workers) exposed to at least 10 times the NIOSH REL. The industry that was found to have the highest percentage of workers (6%) exposed to at least the NIOSH REL was the cut stone and stone products industry. CONCLUSION: Not enough is being done to control exposure to respirable crystalline silica. Engineering controls should be instituted in the industries indicated by this work.

Secondary fractures associated with external fixation in pediatric femur fractures.

Sixty-six femur fractures sustained by children ages 4-14 years and treated with external fixation were reviewed retrospectively to assess factors influencing the incidence of refracture. The total rate of secondary fracture was 12% (eight patients) including five recurrent fractures at the original fracture site and three fractures through the pin sites. After removal of the external fixator, five patients refractured at the original fracture site and one patient fractured through a pin tract. Two patients fractured at pin sites while the fixator was still in place. Multivariate linear-regression analysis showed no correlation between the incidence of refracture and fracture pattern, percentage of bone fragment contact after fixator application, type of external fixator, or dynamization. A statistically significant association (p < 0.05) was found between the number of cortices demonstrating bridging callus [on both anteroposterior (AP) and lateral views] at the time of fixator removal and the rate of refracture. Fractures showing fewer than three cortices of bridging callus had a three (33%) in nine rate of refracture, whereas fractures with three or four cortices of bridging callus had a two (4%) of 57 rate of refracture.