The Anatomical And Radiographic Measurements Of The Presacral Approach For Axial L5-S1 Intervertebral Fusion In Chinese Adults

Objective:To investigate some correlated data with a approach via the presacral space for axial lumbosacral interbody fusion (AxiaLIF) in order to evaluate the safety of the axial access technique in Chinese adults.Methods:(1)The distance from the sacral midline at the S1/2 level to the middle sacral arteries, internal iliac arteries and veins;and the thickness of the mesorectum were measured in 20 human cadaveric specimens(8 men,12 women),with average age of 56 years ranging from 26 to 86 years. The distance from the most medial of the right internal iliac vessels to the most medial of the left internal iliac vessels was calculated.(2) MR images of the lumbosacral vertebraes were obtained from 120 patients with lower back pain(46 men,74 women),with average age of 56 years ranging from 18 to 90 years. The shortest distance from the anterior margin of the sacrum to the mesorectum was measured on median sagittal plane. (3) A"operating space"for setting up a working channel for AxiaLIF was determined using the shortest sagittal length of the presacral space and the distance between the most medial internal iliac vessel on the right and left, respectively.Results:There were no difference in the distances between the sacral midline at the S1/2 level and the homonymic vessels on the right and left both in males and females ,respectively(P>0.05). The most medial internal iliac vessels on the right and left were all the internal iliac veins and the mean distances (transverse diameters with"operating space") in men and women were calculated to be 5.8±0.5cm(range 5.1～6.4cm)and 6.3±0.4cm(5.6～7.0cm), respectively. There was significant difference between the data of male and female groups (P<0.05).The middle sacral arteries were found to be variable in location. The mean thickness of the mesorectum was 0.4±0.1cm(range 0.3～0.5cm).The distance between the anterior sacral margin to the mesorectum was significantly larger in male group than female group[median 1.0 cm(range 0.3～2.3cm) vs 0.6cm(range 0.3～1.8cm),(P<0.01)].Conclusion:It is safe that the approach via the presacral space for AxiaLIF in Chinese adults.