Open burning of household waste: Effect of experimental condition on combustion quality and emission of PCDD, PCDF and PCB.

Open burning for waste disposal is, in many countries, the dominant source of polychlorinated dibenzodioxins, dibenzofurans and biphenyls (PCDD/PCDF/PCB) release to the environment. To generate emission factors for open burning, experimental pile burns of about 100 kg of household waste were conducted with emissions sampling. From these experiments and others conducted by the same authors it is found that less compaction of waste or active mixing during the fire--"stirring"--promotes better combustion (as evidenced by lower CO/CO(2) ratio) and reduces emissions of PCDD/PCDF/PCB; an intuitive but previously undemonstrated result. These experiments also support previous results suggesting PCDD/PCDF/PCB generation in open burning - while still highly variable - tends to be greater in the later (smoldering) phases of burning when the CO/CO(2) ratio increases.

Surgical removal of epidural and intradural polymethylmethacrylate extravasation complicating percutaneous vertebroplasty for an osteoporotic lumbar compression fracture. Case report.

The authors report the case of patient with a lumbar vertebral body osteoporotic compression fracture who underwent percutaneous transpedicular polymethylmethacrylate (PMMA)-assisted vertebroplasty in whom extravasation of the cement into the spinal canal caused immediate neurological deterioration. Lateral lumbar radiography and computerized tomography scanning demonstrated the presence of intraspinal PMMA. The patient suffered severe low-back pain, left-sided sciatica, and profound left L2-4 distribution weakness and numbness. She underwent immediate L-2 laminectomy, the extra- and intradural PMMA was removed, and instrumentation-assisted lateral mass fusion was performed. The patient recovered without incident and her neurological deficit improved. Extravasation of cement into the spinal canal, neural foramen, paraspinal veins, or disc space has been reported in 11 to 73% of percutaneous transpedicular PMMA-assisted vertebroplasty procedures. It is disturbing that more than one group of authors has documented symptomatic spinal canal PMMA extravasation and that the patients were left severely handicapped because of a stated fear that surgery to remove the cement would be difficult and make them worse. The results achieved in this case refute that published notion. It is important to document that decompressive surgery and PMMA removal from the spinal canal are easy and can lead to immediate neurological improvement. With the increasing popularity of percutaneous transpedicular PMMA-assisted vertebroplasty, the authors suspect that more of these cases will be seen.

Traumatic thoracic spinal fracture dislocation with minimal or no cord injury. Report of four cases and review of the literature.

OBJECT: Thoracic fracture dislocations reportedly lead to complete paraplegia in 80% of cases. It is rare for these dislocations not to cause neurological deficits, as evidenced by the mere 11 well-documented neurologically intact cases in the English-language literature. METHODS: The authors report four cases of thoracic fracture dislocation that remained neurologically intact and discuss 11 other previously published well-documented cases. Overall there were 10 men and five women with a mean age of 34 years (range 17-66 years). Mechanisms of injury included car crash in six, motorcycle crash in seven, plane crash in one, and fall from a horse in one. On admission, neurological deficits were absent in 11 patients, intercostal neuralgia was present in two, and mild lower-extremity weakness/numbness was demonstrated in two. All suffered significant thoracic pain, with 14 patients having sustained rib fractures and eight a hemothorax. The levels of dislocation were T3-4 in two, T5-6 in four, T6-7 in four, T7-8 in two, T8-9 in one, and T9-10 in two. All suffered some degree of lateral translation (mean 12 mm, range 3-27 mm). There were six cases of well-documented anterior subluxation in addition to translation (mean 12 mm, range 4-23 mm), and all involved some degree of fracture imploding of one vertebral body (VB) into an adjacent VB. There were six cases of burst fracture with translation (mean kyphotic angle 38 degrees, range 28-50 degrees). Bilateral pedicle shear fractures were present in all 15 cases at the site of subluxation, thus separating the anterior from the posterior elements and preserving the spinal canal. Only two of the 15 patients suffered complete spondylolisthesis. Five patients underwent successful nonoperative management with prolonged bed rest; at follow-up examination, neurological status remained normal in all five, lesions were radiographically unchanged in three, and there was less subluxation but not anatomical alignment in two. Ten patients underwent successful internal fixation via anterior approaches (two cases), posterior approaches (five cases), and combined approaches (three cases). Neurological status either improved to normal or remained normal except in one case with persistent intercostal neuralgia. Surgery resulted in no change in alignment in three, improved but not anatomical alignment in 11, and normal alignment in one patient. All patients ambulated unassisted by 6 months. CONCLUSIONS: In cases in which bilateral pedicle fractures occur at the site of significant thoracic subluxation and/or translation, preservation of the spinal canal and spinal cord neurological function can rarely occur when both the lamina and spinal cord do not dislocate along with the anterior VBs. In these instances, perfect anatomical reduction may require forces that unnecessarily put neurological function at risk and the results appear to justify internal fixation with some or no reduction of deformity.