Experimental study of reflectance spectrophotometric analysis of the dog's dural sac--in the open decompressed state and after the application of external dural pressure.

Haemoperfusion and oxygen saturation were studied by tissue reflection spectra on the dural sac of dogs, Experimentally, decompression laminectomy and external pressure on the dural sac were carried out. Haemoperfusion and oxygen saturation were investigated in the open state, and after an external pressure was applied. After the application of external pressure, paraplegia occurred. The tissue Spectrum Analyser 'TS-200' (Sumitomo Electric Industries Co. Ltd, Japan) was used for the measurement of haemoperfusion and oxygen saturation. With this apparatus, an optical fibre probe is applied to irradiate tissue with white light, and the absorption spectrum of the reflected light from tissue is analysed. It has been confirmed that oxygen saturation was not changed in either state, however, haemoperfusion was decreased when external pressure was applied.