EPIDUROSCOPY VIA THE SACRAL CANAL - ANATO MICAL AND BIOMECHANICAL REQUIREMENTS TO BE MET BY THE INSTRUMENT DESIGN

To ensure optimal mechanical functioning of the vertebral column, inta ct symmetry of its bony and muscular elements is mandatory. With this in mind, the need to reduce the invasiveness of spinal surgery is even greater than that applying to surgery in general. To avoid bony or mu scular damage during surgery, in particular in the case of the segment s L4/L5 and L5/S1 - which are particularly prone to intervertebral dis c rupture - laser discotomy procedures, with introduction of instrumen ts via the sacral canal during epiduroscopy are presently being develo ped. Preliminary experiments on human corpses have demonstrated the pr acticability of the technique, but specially designed instruments have yet to be developed for use in patients. In an attempt to define the conditions of important for the design of the instrument, we have carr ied out a morphometric analysis of 100 sacral bones (56 females; 44 ma les). The configuration of the sacral canal is described in quantitati ve terms, and the results used to determine the diameters and curvatur es of the instruments needed for laser discotomy.