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

Two thirds of the adult population is at least once in their life affected by back pain. This pain, as is usually described by the patients, stands in closer sense for complaints of the lower lumbar spine and/or of the lumbosacral transition [1]. Back complaints, mainly in the form of lumboischialgic pain, have themselves since the 20’s years turned to be the most expensive musculosceletal diseases in the industrialized countries [2]. Therefore is the scientific interest in further diagnostics and therapy of these patients large. This corresponds particularly in patients, who revealed no pathological findings in the conventional diagnostic studies. New diagnostic and therapeutic methods were become necessary and minimal invasive neurosurgical procedures have been developed, in order to face this problem, such as neuroendoscopy and thecaloscopy [3–6]. Thecaloscopy is the endoscopy of lumbar subarachnoid space performed through different approaches in the lumbosacral spinal canal by using flexible endoscopes. For thecaloscopy there are many approach possibilities available, such as translumbar (L3-L4 level) and transsacral (S1-S2 level or through the sacral hiatus) [6–8]. The knowledge of the morphometric anatomic dimensions of this region is a precondition for the atraumatic use of flexible endoscopes. Furthermore, by using MRI studies the determination of ageand sex-specific mean anatomic morphometric values of the sacral spinal canal is possible without the use of cadaver measurements. The measurement values, which originated in the past years particularly from the sectioning of cadavers, were representing actually only one age group, these beyond of 7th decade of life. The goal of this study was to prove that transsacral endoscopy, from the pure anatomic site of view, is possible.