The dimensions of the sacral spinal canal in thecaloscopy: a morphometric MRI study

The subject of this study was the measurement of certain anatomic diameters in the sacral spinal canal by usingthe lumbosacral MRI studies of 25 patients with unclear pain symptoms, in order to estimate, from the pure anatomic point of view, the capability to perform thecaloscopy in this anatomical region. Since now anatomic morphometric data of the sacral region were delivered only from the cadaver specimens’sectioning performed in anatomic institutes during the 60’s and 70’s years. The parameters measured were: 1) the inclination of the lumbosacral angle, 2) the duralsack’s end, 3) the length of all the sacral spinal processes, 4) The length of the sacral spinal canal in its centre, and 5) The width of the sacral hiatus. The results of the measurements were in detail presented and an evaluation of them concerning the applicabilityof flexible endoscopes in the sacral spinal canal was performed. It was proven that the duralsack’s end in 40%of the patients at the middle of the S2 vertebral body lies, an anatomical position, which through the sacral hiatus easy to access is. The length under the sacral spinal processes is smaller than the length of the sacralspinal canal in its centre, a fact that makes the manipulation of a flexible endoscope easier, if someone works straight under the spinal processes and has a smaller distance to run. Through the sacral hiatus the introduction of the flexible endoscope is by many patients possible because of its adequate width.