| Background:Lumbosacral vertebra disease such as serious fracture, infection and tumor canlead to injury of anterior and middle column. Anterior approach is an importantmethod with direct vision, thoroughgoing decompression, recovering mechanicalstructure and direct fixation. Anatomy is complex and operation is difficult in theanterior area of lumbosacral vertebra. Nowadays research of this area is fasten onanterior approach, while fixation section and space of this approach is restricted.Exposure section is wide and expansibility is excellent in the anterolateral approach,while relevant researches such as area of anterolateral space, affection of ligaturesectional vessels, influence of iliac block and angle, length of screw are lack.Objective:To provide practical anatomy and radiographic data about the lumbosacral areafor developing lumbosacral anterolateral approach internal fixation by measuring therelated data.Methods:Thirty-six adult cadavers (18males and18females) and60healthy adults (30males and30females) with three-dimensional(3D) CT scan in the lumbosacral area,collect Digital imaging and communications in medicine(DICOM) data and3D imagewith mimics were measured with the undermentioned data.(1)To anatomic measure the area of lumbosacral anterolateral space(S1) and thearea of space(S2) with ligaturing sectional vessels and stretch abdominal aorta(AA)and inferior vena cava(IVC).(2)To anatomic measure the distances between left common iliac vein(LCIV)and lumbosacral vertebra.(3)To anatomic measure the block area of ala ossis ilii(BAA) and block rate ofala ossis ilii(BRA), computer aided design(CAD) imaging measure the same data.(4)To CAD imaging measure the anterior screw angle(ASA), posterior screwangle(PSA) and screw passageway length(SPL) of S1vertebra. Results:(1)The area of lumbosacral anterolateral space(S1) was31.70±1.8cm2for maleand30.44±2.3cm2, the area of space(S2) with ligaturing sectional vessels and stretchabdominal aorta(AA) and inferior vena cava(IVC) was34.14±1.0cm2for male and32.56±1.6cm2for female, there was a significant difference(P <0.01) between initialstate and sectional vessels were ligatured.(2)The distance(V1) between left common iliac vein(LCIV) and L5posteriorsuperior marginal was43.62±0.8mm for male and42.98±1.0mm for female, thedistance(V2) between LCIV and L5posterior inferior marginal was40.51±0.6mm formale and41.33±0.7mm for female, the distance(V3) between LCIV and S1posteriorsuperior marginal was31.75±0.9mm for male and29.46±0.6mm for female, therewas not a significant sex difference(P>0.05).(3)The anatomic measure the block area of Ala ossis ilii(BAA) was171.62±0.9mm2for male and122.91±0.7mm2for female, the block rate of Ala ossisilii(BRA) was52.14±0.8%for male and39.83±1.0%for female, there was asignificant sex difference(P <0.01). Computer aided design(CAD) imaging measurethe BAA was184.53±0.9mm2for male and142.76±0.7mm2for female, the BRA was56.55±0.8%for male and42.12±1.0%for female, there was a significant sexdifference(P <0.01). There was not a significant difference (P>0.05) between theanatomic measure and CAD imaging measure.(4)The anterior screw angle(ASA) of S1vertebra was52.61±0.7°for male and50.49±0.9°for female, the posterior screw angle(PSA) of S1vertebra was37.46±0.9°for male and33.62±0.6°for female, there was not a significant sexdifference (P>0.05). The posterior screw passageway length(SPL1) of S1vertebrawas46.13±0.7mm for male and44.22±0.4mm, the anterior screw passagewaylength(SPL2) of S1vertebra was48.96±0.3mm for male and46.84±0.5mm, there wasnot a significant sex difference(P>0.05).Conclusion:(1)The lumbosacral anterolateral space is a long and narrow orthogonaltrapezium, and the effective area is33.35cm2. The should be considered before theinternal fixation is selected. (2)The distance between LCIV and L5posterior superior marginal was43.30mm.The distance between LCIV and L5posterior inferior marginal was40.92mm. Thedistance between LCIV and S1posterior superior marginal was30.61mm. Thedistance should not be exceeded when exposure vertebra to avoid injury of LCIV.(3)The BRA is between38%-62%in the anterolateral approach and the block ofala ossis ilii of male is more significant than female. We can pre-evaluation thepossibility of anterolateral approach operation with measure the BRA and computingthe vestigial area whether or not it can hold fixation before operation.(4)The ventral lean angle of anterior screw is not exceeding51.55°and the lengthis not exceeding47.90mm. The ventral lean angle of posterior screw is not exceeding35.54°and the length is not exceeding45.18mm. In this scope we can avoid theintraspinal injury when the screw is inserted into the S1vertebra in the anterolateralapproach,... |
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