Real-time total integrated scattering measurements on the Mir spacecraft to evaluate sample degradation in space.

An instrument to measure total integrated scattering (TIS) in space was built as part of the Optical Properties Monitor instrument package and flown on the Russian Mir Space Station in a low Earth orbit. TIS at two wavelengths was measured in space at approximately weekly intervals from 29 April to 26 December 1997 and telemetered to Earth during the mission. Of the 20 TIS samples, 13 are described here to illustrate the performance of the TIS instrument. These include ten optical samples and three thermal control samples. Two optical samples and one thermal control sample were severely degraded by atomic oxygen. All samples received a light dusting of particles during the mission and an additional heavier layer after the samples returned to Earth. The initial brassboard instrument and the validation tests of the flight instrument are also described.

Use of long rods and a short arthrodesis for burst fractures of the thoracolumbar spine. A long-term follow-up study.

Thirteen patients who had a burst fracture of the thoracolumbar spine (the twelfth thoracic to the fifth lumbar vertebra) were managed with the use of long rods and a short arthrodesis (the so-called rod-long, fuse-short technique). The patients were followed for an average of seventy-four months (range, thirty-four to 118 months). Six months after the operation, the rods were removed and the fusion mass was explored. At that time, twelve patients had a solid fusion at all levels of the arthrodesis. Of the eighty-eight facet joints that had been spanned by the rods but had not been included in the arthrodesis, two had nevertheless progressed to fusion, as determined radiographically. Physiological motion was present in forty-three of the forty-four segments for which a fusion had not been intended. Before the operation, the average anterior height of the fractured vertebrae was 61 per cent of the estimated height before the injury; this improved after the operation to an average of 83 per cent (median, 87 per cent) of the height before the injury. At the latest follow-up examination, the anterior height was an average of 78 per cent of the estimated height before the injury (median, 82 per cent; range, 51 to 93 per cent), a slight decrease compared with the value immediately after the operation. Kyphosis of the injured segment before the operation, measured for twelve of the thirteen patients, averaged 15 degrees (median, 12 degrees; range, 0 to 33 degrees); as a result of the operation, this improved an average of 15 degrees, to 0 degrees of kyphosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anterior exposure of the thoracic spine.

Spinal operation via an anterior thoracic approach is becoming increasingly common, and the thoracic surgeon is now being called upon to provide exposure for orthopedic and neurosurgical colleagues. We report experience with 126 such patients from 1982 through 1993. There were 61 male and 65 female patients (mean age, 39.0 years; range, 14 to 77 years). Indications were trauma in 45 patients (36%), spinal deformity in 42 (33%), cancer in 15 (12%), disc disease in 12 (10%), and infection in 12 (10%). Operative incisions included 22 (17%) right and 14 (11%) left thoracotomies, 33 (26%) right and 56 (44%) left thoracolumbar approaches, and one (1%) sternotomy. A prior spinal operation had been performed on 31 patients (25%), and 56 (44%) had a subsequent posterior spinal operation. Instrumentation was used in 38 (30%) and bone grafts in all but 6 patients. A neurologic deficit was present in 69 patients (55%) preoperatively and was improved in 67 patients postoperatively. Operative mortality was 3.2% (4 patients) due to myocardial infarction, stroke with pneumonia, adult respiratory distress syndrome, and malignant biliary obstruction. Univariate and multivariate risk analysis were performed. Only the diagnosis of osteomyelitis proved to be a significant (p = 0.0002) indicator of operative mortality, with 3 of 12 such patients dying (25%). These results suggest that anterior spinal exposure via thoracic approach is a major operation with considerable perioperative risk. Patients with osteomyelitis appear to be at increased risk for operative mortality.

Second operation for slipped capital femoral epiphysis: pin removal.

Pin removal procedures were retrospectively reviewed for 43 hips in 31 patients. Original treatment had included use of Knowles, Steinmann, Hagie, and cannulated steel pins. Time to pin extraction ranged from 5 to 70 months. Average operative time was slightly more than 1 h and average blood loss was 127 ml. Bone overgrowth and difficult extraction was encountered with all pin types. Pin breakage during extraction was recorded with Steinmann and Knowles pins. Delay in return to full activity postoperatively was a common complaint. This study shows that pin removal is not without certain costs and risks.