The treatment of complex dural arteriovenous fistulae through cranial base techniques

Introduction: The endovascular modality of treatment is the preferred treatment modality for DAVF. In some circumstances, successful obliteration may not be possible by endovascular means, and such cases may require a direct surgical treatment. The authors report on their experience with the use of cranial base approaches in the treatment of deep and complex DAVF. Materials and Methods: Nine patients were treated between 1992 and 2003. There were six females and three males. Four patients presented with intracerebral hemorrhage, two with progressive myelopathy, two with tinnitus, and one with incapacitating chronic seizures. Four DAVF were tentorial, two transverse sigmoid, one craniocervical, one straight sinus, and one sphenoparietal. Endovascular embolization was attempted and unsuccessful in four cases, and was successful only as an adjunct to surgery in four others. All patients required the use of cranial base approaches to disconnect the fistula or resect the nidus. Results: Complete obliteration of the fistula was possible in all cases. Six-month follow-up results were obtained on seven patients where there was no evidence of recurrence. One postoperative temporal-lobe hematoma required surgical evacuation. One patient died two years postoperatively from an unrelated cause. Conclusion: This retrospective study demonstrates that complex DAVF can be successfully treated with the assistance of cranial base techniques

Rapid declines in metabolism explain extended coral larval longevity

Lecithotrophic, or non-feeding, marine invertebrate larvae generally have shorter pelagic larval durations (PLDs) than planktotrophic larvae. However, non-feeding larvae of scleractinian corals have PLDs far exceeding those of feeding larvae of other organisms and predictions of PLD based on energy reserves and metabolic rates, raising questions about how such longevity is achieved. Here, we measured temporal changes in metabolic rates and total lipid content of non-feeding larvae of four species of reef corals to determine whether changes in energy utilization through time contribute to extended larval durations. The temporal dynamics of both metabolic rates and lipid content were highly consistent among species. Prior to fertilization, metabolic rates were low (2.73–8.63 nmol O2 larva⁻¹ h⁻¹) before rapidly increasing to a peak during embryogenesis and early development 1–2 days after spawning. Metabolic rates remained high until shortly after larvae first became competent to metamorphose and then declined by up to two orders of magnitude to levels at or below rates seen in unfertilized eggs over the following week. Larvae remained in this state of low metabolic activity for up to 2 months. Consistent with temporal patterns in metabolic rates, depletion of lipids was extremely rapid during early development and then slowed dramatically from 1 week onward. Despite the very low metabolic rates in these species, larvae continued to swim and retained competence for at least 2 months. The capacity of non-feeding coral larvae to enter a state of low metabolism soon after becoming competent to metamorphose significantly extends dispersal potential, thereby accruing advantages typically associated with planktotrophy, notably enhanced population connectivity