Imaging Anatomy And Clinical Application Studies Of Anterior Multidirectional Self-locking Plate For The Treatment Of Lumbosacral Tuberculosis

BackgroundLumbosacral spine has a complex anatomical structure and special biomechanical properties,tuberculosis can cause the vertebral bone destruction and collapse,leading to difficult to cure.Most patients require surgical treatment to debride and reconstruct of spinal stability.For a long time,anterior and posterior approaches have brought great trauma to the patients.Because of the small trauma,one-stage anterior approach has been paid more and more attention by surgeons.The purpose of this study is to investigate the imaging anatomy and clinical application of anterior debridement combined with self-developed multidirectional self-locking plate for the treatment of lumbosacral tuberculosis.The triangular “avascular zone” in anterior lumbosacral spine section,constituted by the iliac vessels crossing from both sides together with the sacral promontory,is commonly recognized as the safe operating region for anterior lumbosacral surgery.Inflammation causes adhesion of the iliac vessels and the surrounding tissue,making intraoperative free and migrating vessels very difficult,so surgery and placement of fixation in the "avascular zone” can reduce the risk of vascular injury.The iliac vessels may be affected by a presacral abscess moving forward and possibly forming a gap to the anterior vertebral body in the sagittal plane.It may provide some space for internal fixation placement after debridement surgery,and can avoid delayed vascular injury risk caused by friction between iliac vascular pulsation and the internal fixation.Previous studies on the “avascular zone” have only focused on healthy populations and have also only focused on their anatomical characteristics in the coronal plane,there was few reports about lumbosacral tuberculosis.The existing anterior fixation system is not suitable for patients with lumbosacral tuberculosis,our group developed an anatomical anterior lumbosacral internal fixation device that complies with the characteristics of lumbosacral spine tuberculosis,according to the anatomy of lumbosacral segments,iliac vessel shape and the destruction of endplate caused by tuberculosis.The multidirectional self-locking plate can nail through the area that destroy less according to the actual case of bone destruction,and can achieve a screw angular stability by “multidirectional self-locking” technique.Objective(1)On the basic study of "avascular zone" in the anterior normal lumbosacral spine,to further observe the effect of tuberculosis on the "avascular zone" and to explore the anatomical basis of anterior surgery of lumbosacral tuberculosis.(2)To observe the clinical safety and efficacy of one-stage anterior debridement,bone grafting and internal fixation for the treatment of lumbosacral tuberculosis with the self-developed multidirectional self-locking plate.Methods(1)To review the preoperative 3D-CTA images of 36 patients with lumbosacral tuberculosis treated by our department from 2010 to 2015,and to observe and measure the relative 3D anatomical relationship of traveling iliac vessels caused by tuberculosis cold abscess and vertebral bone destruction,and the "avascular zone".(2)For a total of 35 cases of lumbosacral tuberculosis treated with one-stage anterior debridement,bone grafting and internal fixation between 2010 and 2015,preoperative CT angiography was used to assess the anatomical structure of "avascular zone".A relatively complete region of bone structure was chose to place the multidirectional self-locking plate during operation.Postoperative regular follow-up to assessment of tuberculosis activities,bone graft fusion,orthopedic maintenance,neurological recovery and complications.Results(1)Forming the two side borders of the presacral “ avascular zone” in the anterior lumbosacral spine,the most common situation was the left side iliac vein and the right side iliac artery,accounting for 86.1% of the cases.The distance between both straddle point and the L5 lower edge was 15.0 ± 15.1 mm.The abdominal aortic bifurcation point was mostly common observed at the L4 level,accounting for 61.1% of the cases;a confluent point of the common iliac vein was mostly common observed at the L5 level,accounting for 41.7% of the cases.The widths between the inner edges on both sides of the iliac vessel at the L5 lower edge and the S1 upper edge levels were 30.2 ± 17.9 mm and 37.8 ± 16.7 mm,respectively.The sagittal diameters of tuberculosis abscess in the sagittal plane were 7.8 ± 3.8 mm and 10.5 ± 5.2,respectively.The maximum abscess sagittal diameters were 10.8 ± 4.4 mm and 13.7 ± 6.1 mm,respectively.The distances between the iliac vascular posterior wall and the anterior vertebral body at both sides of the L5 lower edge were 9.9 ± 6.0 mm and 10.2 ± 5.5 mm,respectively,and the distances at both sides of the S1 upper edge were 11.9 ± 6.9 mm and 11.8 ± 5.4 mm,respectively.(2)35 cases were followed up,the mean follow-up period was 26 months.The average operation time was 149 minutes,and the intraoperative blood loss was 257 ml.There was no injury of blood vessel,cauda equina or ureter during surgery.After surgery the lumbosacral pain eased significantly,and there was no deep venous thrombosis,impotence,retrograde ejaculation or recurrence in any of these patients.The intervertebral bone graft reached grade ? at the 12 th month after surgery.The average preoperative ESR,CRP,VAS,ODI,lumbosacral angle were 32.14±9.87 mm/h,23.66±9.98 mg/L,4.80±1.02,(27.47±6.79)%,(23.09±3.21)°,respectively.The average postoperative lumbosacral angle was(29.21±1.16)°.The average last follow-up ESR,CRP,VAS,ODI,lumbosacral angle were 5.34±2.30 mm/h,1.26±0.55 mg/L,0.83±0.71,(4.31±1.49)%,(26.71°±1.57)°,respectively.Conclusions(1)The iliac vessels of lumbosacral tuberculosis patients had a large variation,and in the sagittal plane,the additional space formed in front of the vertebral body due to the impact of the tuberculosis can provide more possibilities for the placement of the internal fixation.(2)One-stage anterior debridement,bone grafting and internal fixation for treating lumbosacral tuberculosis is safe and effective,and the multidirectional self-locking plate produce good clinical outcomes for patients with lumbosacral tuberculosis.