Artikel
Laser speckle contrast analysis allows the intraoperative assessment of spinal autoregulation
Laser Speckle Contrast Analysis ermöglicht eine intraoperative Bestimmung der spinalen Autoregulation
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Veröffentlicht: | 25. Mai 2022 |
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Gliederung
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Objective: In the central nervous system, autoregulation is an adaptive mechanism to maintain a constant perfusion despite changes in blood pressure. In the recent years, studies have shown, that several pathologies like traumatic brain injury, ischemic stroke, or cerebral tumors result in an impaired cerebral autoregulation. This deficit was shown to be a predictor for worse patient outcome. However, studies on spinal autoregulation (SA) and its potential impairment in pathologies are rare. In this pilot study, we intraoperatively assessed the SA in response to changes in blood pressure in patients with intradural tumors using non-invasive Laser Speckle Contrast Analysis (LASCA).
Methods: In 4 patients with intradural tumors (hemangioblastoma, pilocytic astrocytoma, meningioma, schwannoma), intraoperative LASCA imaging (FLPI2, Moor Instruments) was performed before and after tumor resection. During LASCA imaging, 10 mmHg mean arterial blood pressure (MAP) changes were induced, and the relative response of spinal blood flow (SBF) was recorded by LASCA. The SA was calculated at the tumor site as well as within an area of intact spinal cord.
Results: Functional autoregulation was observed in areas of the spinal cord without tumor infiltration. In these areas, the SBF remained relatively constant to changes in MAP (+0.41 ± 0.24% SBF per mmHg MAP↑). In contrast, all four patients showed a severe impairment of SA at the location of the tumor, which resulted in a significant increase in SBF in response to blood pressure changes (+2.63 ± 1.28% SBF per mmHg MAP↑). Following tumor resection, the SA improved at the resection-site of the tumor (+1.97 ± 1.39% SBF per mmHg MAP↑) and at the surrounding intact spinal cord (+0.23 ± 0.15% per mmHg MAP↑).
Conclusion: SA can be assessed intraoperatively using non-invasive LASCA imaging in intraspinal tumor surgery. Functional SA was observed in areas of intact spinal cord whereas the SA was impaired in tumor infiltrated areas. LASCA imaging allows an intraoperative real-time detection of impaired SA and thus, has a positive impact on intra- and postoperative risk-assessment, especially in regard to spinal infarction or bleeding. However, this technique is limited to intraspinal pathologies since opening of the dura is required for LASCA imaging of the spinal cord.