Operative safety analysis of transforaminal lumbar interbody fusion in Chinese people based on the anatomical study by magnetic resonance neurography

Abstract

Objective To measure the related anatomical parameters of lumbosacral nerve root and adjacent structures by magnetic resonance neurography,and to analyze operative safety of transforaminal lumbar interbody fusion in Chinese people.Methods A total of 12 healthy volunteers,including 6 males and 6 females,underwent magnetic resonance neurography of lumbosacral nerve root using a Siemens 3.0T MRI machine.The Osirix software was used to reconstruct the three-dimensional imaging and measure the following anatomic parameters: 1) the distance between the nerve root and the superior pedicle; 2) the distance between the nerve root and the inferior pedicle; 3) the angle between the nerve root and the sagittal plane; 4) the distance between the superior and inferior nerve roots; 5) the distance between the superior and inferior pedicles.Results L1-L5 nerve roots got a good imaging by magnetic resonance neurography in all 12 volunteers.The distance between the nerve root and the superior pedicle and the angle between the nerve root and the sagittal plane gradually became smaller from L1 to L5.But the variation in the distance between the nerve root and the inferior pedicle and the distance between the superior and inferior pedicles was not obvious.The distance between the nerve root and the inferior pedicles,which was closely related to the operating space of TLIF,ranged from (8.99±0.88) mm to (10.72±1.01) mm for males and from (7.76±0.46) mm to (8.54±0.65) mm for females; it was less than 10 mm in each segments in the majority of subjects,and the data of females was significantly smaller than that of males.No significant differences were found in parameters between the left and right sides in the same segment.Conclusion Based on the above anatomical study and measurement analysis,we believe that there is some harassment to the upper nerve root in TLIF for Chinese patients,and for some patients there is a certain injury risk. Key words: Lumbar vertebrae; Spinal fusion; Spinal nerve roots; Magnetic resonance imaging