Nghiên cứu đặc điểm thương tổn giải phẫu và kết quat phẫu thuật điều trị gãy cột sống ngực thấp và thắt lưng không vững do chấn thương bằng nẹp vít tt tiếng anh

1 BACKGROUND A thoracic and lumbar spinal injuries account for the majority, about 90% of spinal injuries In which, thoracolumbar spine hinge vertebra (T11 - L2) and lower lumbar (L3 - L5) account for about 84%, mainly with the indirect mechanism Classification emphasizes on: the form of injury, integrity of the posterior ligamentous complex and nerve damage The role of the posterior ligamentous system in the stable spinal structure is confirmed and appreciated by many authors This is an issue that needs to be paid more attention to in the diagnosis and treatment of spinal injury in Vietnam when no previous research has specifically and fully mentioned before For surgical indication,the authors based on the loss of steadiness of the injured spinal vertebra on the basis of the morphologic damage, nerve damage, and posterior ligamentous complex However, each indication has its own advantages and disadvantages Recent studies have been made on the validity and reliability of Vaccaro AR’s TLICS (thoracolumbar injury classification and severity score) and indicate cases where scores of to had to undergo surgery late after a conservative treatment period, or narrow scope of application in the multiple vertebral fracture group under the indication of McCormack and Wood KB Posterior approaches for treatment of thoracic spinal injury is becoming more and more popular, effective and dominant The efficiency of multiple vertebral fracture surgery has been enhanced, and demonstrated in studies by Smith JS, Ataka H., Kaminski A The findings of Greenberg MS about degenerative joint diseaserequired for early surgery after years in long band fixations (≥ bands) after to years in short band fixations (2 to bands) Therefore, from these issues, we carry out the topic: “Study on surgical injury characteristics and results of surgery for treatment of the lower thoracic and lumbar spinal fractures due to traumatic injury by splints and screws” with two goals: Description of surgical injury characteristics and deformation on the image diagnosis, survey of TLICS and LSC values in lower thoracic and lumbar spinal injury Evaluate the results of surgery for the treatment of lower thoracic and lumbar spinal fractures with posterior splints and screws CHAPTER OVERVIEW 1.1 Surgery The lower thoracic and lumbar spine consists of a relatively straight, vulnerable thoraco- lumbar spine hinge vertebra (T11 L2) by a longitudinal compression and a lower lumbar vertebra (L3 – L5) with a physiological curve opening backward to absorb force in the spring type so that it causes less injury Vertebral body has weak structure in from column, stable structure in middle and back columns Thus, injury often occurs in the front column under the vertical compression mechanism According to Benzel E.C., the proportion of periosteum and bone marrow affects the bearing capacity and the anti-screw loosening strength This rate is higher in the spinal stalk than in vertebral body and higher in the thoracic - lumbar spine hinge vertebra than in lower lumbar vertebra Therefore, spinal stalkis the strongest part of the vertebrae and the T11 - L2 segment is stronger than the L3 - L5 segment The joint system between vertebrae is composed of two main types of joints: Cartilaginous (semi-moveable) joint and the Synovial (freely moveable) joint Of which, the Synovial (freely moveable) joint and ligament joint (rear ligament system) play an important role in steadiness, flexibility and maintaining the amplitude for movement of the spinal column.The vascular system nourishing the thoracic and lumbar marrow, including the root vascular system, spinal marrow vascular system and coronary artery network Accordingly, Adam kiewiczcung artery provides mainly for 4/5 marrow in cross section from T8 to conus medullaris 1.2 Biological mechanisms behind injury and nerve damage in spinal injury 1.2.1 Biological mechanisms behind injury According to Benzel E.C., the force acting on the spinal column, in terms of the three-dimensional space system on each coordinate axis, has two axial sliding motions and two reciprocating rotating movements that produce 12 movements around the instantaneous axis of rotation (IAR), forming up to six levels of free movement around the IAR axis in association with each other to creating forces: press – compression, cutting – shearing, twisting, stretching – tearing resulting in different forms of damages in a trauma Instantaneous rotation axis is the imaginary point in or around the vertebrae where the spinal segment rotates under the impact force When the impact force is non-coaxial with IAR, it generates a bending moment (M) of magnitude equal to the magnitude of the force (F) multiplying by the distance from the point of impact to the instantaneous rotation axis (D) The bending moment (M) is defined as the product of the force (F) applied to the lever arm and the length of the lever arm (D) : M = F x D 1.2.2 Nerve damage In spinal trauma, there are four major traumatic mechanisms involved in nerve deformation in the long term: extrinsic nerve compression, diffusion, arch effect on the vertical plane, arc effect on the horizontal plane It has two forms of lesions: primary lesions and secondary lesions Disorders or malfunction of nerve cells due to the mechanism of: cell destruction leads to nerve cell death and cell deformation, metabolic disorders leading to temporary or permanent malfunction Surgery removing the compression factors can prevent, overcome cell deformation and metabolic disorders Secondary nerve damage may be prevented partially at least by medicine interventions: anticoagulant medicine therapy and corticoide therapy are recommended to use as soon as possible within the first to 72 hours after injury 1.3 Classification of injuries 1.3.2 Classification of Denis (1983) In 1983, Denis introduced the three column concept of spinal fractures: anterior column (the anterior vertebral body, ½ anterior annulus fibrosus, and anterior longitudinal ligament), middle column ( posterior longitudinal ligament, ½ posterior annulus fibrosus, and posterior wall of the vertebral body), the posterior column (spinal canal vein, marrow, posterior ligament system, posterior arch) Denis divides the vertebral body injury into four types: compression fracture (anterior column damage, no injury to the middle column, possible injury to the posterior column), burst fracture (injury to the middle and posterior column by the mechanism of vertical compression in combination with bending, turning, and the posterior fracture piece may press the spinal canal), distraction fracture (the fracture lies at the same level in the vertical plane, the fracture lies in two levels in the vertical plane causing injury to bones, ligaments and annulus fibrosus), dislocation fracture (severe damage to all three columns causing instability) Denis introduced the concept of “stable and unstable spinal injuries” as the basis for indications for treatment in spinal injuries The term “stability fracture” includes mild or moderate subsidence, no injury to the middle and posterior columns, indicating conservative therapy, early movement practice There are three types of instability based on the relationship between morphological and neurological damages: mechanical instability, neurological instability, mechanical - neurological instability, and surgical indication 1.3.3.Classification after Denis McCormack classified fractures based on three factors: the breaking degree of the vertebral body, the cohesion of fractured pieces, the kyphosis being quantified on a scale of to points on each factor by severity status The higher the point, the more severe the injury Indication for surgery in case of – points VaccaroA.R., gave the TLICS classification based on three important traumatic features: injury morphology, integrity of the posterior ligament system, and nerve damage Indication: 510 points => surgery, - points => conservative treatment and points => priority for surgery 1.4 Medical imaging methods main methods: conventional x – ray imaging, computerized tomography and MRI 1.4.1 Conventional x – ray imaging Conventional X-ray imaging has diagnostic value: position; discontinuity of three lines: inter- posterior spinal cord, inter-joint block, inter- horizontal spinal cord; vertebral traumas, angular bending of the traumatic area and the distance between joint blocks and posterior spinal cord The advantage of conventional xray compared to computerized tomography and magnetic resonance imaging (MRI) is that it can be investigated in a dynamic state to diagnose suspected cases of semi-dislocation 1.4.2 Computerized tomography (CT scan) of of spine CT scan have a accuracy rate (sensitivity) of over 98% with bone damage, which is of high value in the classification of spinal fractures Determination of bone loss: reduction of the height of the anterior column, fracture line, separate fracture piece and compression position, joint block lesions, spinal canal, plates, bending angular deformations or dislocation, spinal canal narrow levels However, it is difficult to assess soft tissue lesions such as ligaments, nerves 1.4.3 MRI of spine Magnetic resonance imaging may determine the damage in marrow, soft tissue, posterior ligament complex Marrow edema and marrow contusion without blood bleeding have same signal image or low signal on T1, high signal on T2 Acute or semi-acute bleeding has low signal image on T2, in chronic phase it is a high signal image on T1 and T2 For marrow breaking, the image shows a persistent breaking of the injured segment and the marrow edema, accompanied by haemorrhage Image of ligament injury: sudden loss of signal in a signal decreasing region on T1, increasing signal in the surrounding organisms on T2 Bone damage will have an image of decreasing the signal on T1, increasing the signal on T2, can be defined the bone fracture line, fractured piece compressing the spinal column 1.5 Brief history of the study and treatment of thoracic and lumbar spinal injury 1.5.1 In the world Surgery for treatment of thoracic and lumbar spinal injury was first supported by Gorter more than 200 years ago Prior to 1963, the main treatment was conservative treatment, external correction, posterior arch cut operation and still have limitations Later some authors have applied some methods for fixation in surgery such as steel string tie, hook, brace, Hartshill frame which obtained certain results Posterior surgery actually developed as Roycamille developed, improved the surgical procedure with a screw via the spinal canal (1963 - 1975) This method was then modified by Margel into cluster screw with 5º-15º slanted direction, which is widely used in surgery Today, these two methods become more and more popular and effective in treatment 1.5.2 In Vietnam In Vietnam surgery began to be applied the 70s-80s of the 20th century with the works of Hoang Tien Bao, Vo Van Thanh However, in the 90s of the 20th century, spinal trauma surgery actually strongly developed in Vietnam and successfully applied both anterior and posterior surgery methods Cho Ray Hospital, Viet Duc Hospital, 108 Military Central Hospital, Military Hospital 103 mainly applied the posterior surgery method However, these studies have not addressed the role, conservation and restoration of the posterior ligament complex, nor have they adequately assessed the morphologic trauma on X-ray and investigated the value of TLICS, LSC scales in surgery 1.6.2 Some basic issues in posterior hardening 1.6.2.1 Configuration of foot bow screw system According to Benzel E.C., the screw on the vertebral body will provide a durable traction and compression force on the vertebrae to prevent sliding deformation This force is strongly influenced by the outer diameter of the screw, the ratio of the skeleton to the skeleton in the body and the bow, the diameter of the leg The depth of the screws in the body of the burner is about 50% - 80% When the screw is placed in the leg screw system with adjusting force, it provides a bending and pulling torque for correcting the flexion Corners, slides and compresses the vertical axis At the same time, it is subjected to a bending and shearing moment in the opposite direction, especially at the beginning, end and midpoint of the screw system when the spine is subjected to a load Therefore, system configuration is required The foot screw must be firm enough to provide a sufficiently large force to maintain manipulation of the distal and spine This is the theoretical basis for the construction of fixed-length configurations at two points and fixed longitudinal layers such as three-point bending The bending moment provided by these two fixed configurations is proportional to the length of the structure and has a lateral arm parallel to the spinal axis This is the theoretical basis for the construction of fixed-length configurations at two points and fixed long bands such as three-point bending The bending moment provided by these two fixed configurations is proportional to the length of the structure and has a lever arm parallel to the spinal axis Screw diagrams consist of a straight diagram (slanted angles down to 0º) and an anatomical diagram (slanted angles down to 20º - 25º) In particular, linear diagrams provide superior mechanical biomechanics compared to bolted anatomy We need to consider clearly the instability to make decisions and choose the optimum fixed configuration during surgery According to Greenberg MS, joint degeneration required for surgery should usually occur after years when fixing the long band and – years when fixing the short band Therefore, the authors recommend that if the bone damage is not severe, fixing short band is appropriate CHAPTER SUBJECTS AND RESEARCH METHODS 2.1 Research subjects Study subjects included 89 patients diagnosed with thoracic and lumbar spinal injury, with single band and instability, operated to correct, fix, compress under the posterior method at Military Hospital 103 from 12/2010 to 1/2013 2.1.1 Selection criteria Patients diagnosed with thoracic and lumbar spinal injury according to the criteria for each fracture type of the Greenberg MS, single-band lesions, c operated to correct, fix, compress by screw under the posterior method No sex discrimination, age ≥ 18 2.1.2 Exclusion criteria Patients have chronic diseases that affect the research results such as heart failure, liver failure, kidney failure, other cardiovascular diseases, diabetes Multiple injuries, fractures due to tuberculosis, cancer, mentally ill disorders, no cooperation in treatment, non-compliance with follow-up and re-examinaiton procedures, and lack of adequate research documentation 2.2 Research Methodology 2.2.1 Research design A prospective research describes the clinic status with intervention, evaluates the result results on each patient before and after surgery 2.2.2 Sample size Favorable sample selection includes all patients eligible for selection criteria and exclusion criteria during the study period 2.2.3 Data collection method Information collected according to the unified medical records include: examination and evaluation of patients before surgery; participate in surgery, follow up and treat patients after surgery, directly visit to examine patients after surgery under the medical record form of the research; check patients who return for re-examination in the Department of Neurological Surgery - Military Hospital 103 2.2.4 Research content – Determine the mechanism of injury – Evaluate muscle strength and sensory disorders according to Greenberg M.S criteria, applicable – Evaluate the level of nerve damage accroding to Frankel improvement – Evaluate via x-ray images: fracture position, kyphotic angle, reduction of column height in front of vertebral body, injury level of vertebral body according to McCormack, level of spinal stenosis, position pressing the spine, type of fracture, damage to the rear ligament system – Surgery for removing, correction, fixation by the screw and plint as indicated by Greenberg M.S – Postoperative evaluation at two points: 10 days after surgery and last examination (12 months after surgery) Criteria: Neurological rehabilitation according to Frankel; results of the correction of the kyphotic angle, the height of the column in front of the broken vertebra on the conventional xray according to Keynal; backache, labor recovery by Denis; surgery time, blood loss during surgery, complications, condition of the screw system 2.2.5 Data processing method Use of medical statistic software SPSS 22.0 2.2.6 Research ethics The information about the patient’s illness status in the medical file is completely confidential and only used in the study with the consent of the Vietnam Military Medical University, Military Hospital 103 CHAPTER RESEARCH RESULTS 3.1 Common features 3.1.3 Causes of injury 10 Labor accident Injured accident Traffic accident Normal accident Chart 3.3 Distribution rate of accident causes 12 3.2.6 Evaluate the fracture level of vertebral body according 100 100 to McCormack Compression 82.09 100 fracture 80 60 40 17.91 20 0 I0 II 0 III Chart 3.8 Distribution rate of fracture level of fracture groups 3.2.7 Evaluate the cohesion of71.64 fractured pieces according to Compression 64.71 60 McCormack 80 fracture 60 35.29 40 40 16.42 11.94 20 I II III Chart 3.9 Distribution rate of the cohesion of fractured pieces 3.2.8 Evaluate the kyphotic level according to McCormack 100 50 Lún Compression fracture I Vỡ III Trật Burst fracture I II II Dislocation fracture III Chart 3.10 Distribution rate of the kyphotic level 13 71.64 3.2.9 Evaluate the fracture types64 according to McCormack 80 71 60 rating scale Compression 70 60 50 40 30 20 10 fracture 40 35.29 16.4 11.94 50 09 Chart 3.11 Distribution rate of points 3.2.10 Evaluate the height reduction of the column in front of vertebral body Table 3.3 Height reduction of column in front of vertebral body Reduction index Fracture type Compression fracture (n = 17) Burst fracture (n = 67) Dislocation fracture (n = 5) Standard Smallest Biggest Mean deviation (%) (%) (%) (+/- %) 50 56 51.35 2.29 20 56 35.78 7.54 20 35 27 5.7 p < 0.001 3.2.11 Evaluate the angle bending of the injured area Table 3.4 Kyphotic angle of the injured area Bending level Fracture type Compression fracture Burst fracture Smalles Mea Standard Biggest n deviation t ( 0) (0) (0) (+/-0) 19 29 20 40 23.2 26.3 3.38 3.89 p < 0.001 14 Dislocation fracture 22 35 28.8 5.26 3.2.12 Fracture types and spinal canal narrow levels Table 3.5 Table of spinal canal narrow levels Canal narrow level Fracture types Compression fracture Burst fracture Dislocation fracture p Quantity Not narrow Narrow < 50% Narrow ≥ 50% Quantity % Quantity % 17.65 0 67 14 (82.35) (11.94) 26 38.81 33 49.25 40.00 60.00 17 < 0.001 3.2.13 Causes of spinal canal narrow Chart 3.12 Distribution rate of compression causes 3.2.14 Spinal canal compressing positions 15 Chart 3.14 Distribution rate of spinal canal compressing positions 3.2.15 Fracture type and spinal decompression methods Table 3.6 Decompression method Decompression Direct Quantity % Fracture types Compression fracture Burst fracture Dislocation fracture 34 Indirect Quantity % 17.65 50.75 60.0 14 33 82.35 49.25 40.0 3.2.16 Decompression time Chart 3.16 Rate of decompression time 3.2.17.Decompression group and deformation Table 3.7 Decompression group and deformation Deformation Fracture types Compressio Group Quanti -ty Smalles Standard Biggest Mean t deviation         20 50 29 52 25.1 50.3 3.1 0.8 16 n fracture Burst fracture Dislocation fracture Group Group Group 11 37 30 19 50 29 56 22.1 51.9 3.1 20 25 35 50 27.7 38.5 3.2 20 20 40 56 24.6 32.3 3.9 2.6 6.9 6.9 Group 22 20 35 35 28.8 27.0 5.2 5.7 3.3 Injury to the posterior ligament system 3.3.1 Fracture types and injury to the posterior ligament system Table 3.9 Determine injury to the posterior ligament system by MRI and surgery Criteria MRI Fracture types Compressio n fracture Burst fracture Dislocation fracture Total Quantit y (n) Surgery Injury to the posterior ligament system p Quantit Rate Quantit Rate y (%) y (n) (%) (n) 23.53 23.53 23.53 Quantit Rate y (n) (%) 17 < 0.01 67 10 14.93 10 14.93 10 14.93 60 100 100 89 17 19.10 19 21.35 19 21.35 3.3.2 Evaluate fracture types according to TLICS scale 17 100 100 80 60 Compression fracture 64 71 53.73 40 5.88 2.99 20 3.28 29.4 1-3 0 5-10 Chart 3.17 Distribution according to TLICS scale 3.4 Nerve damage 3.4.1 Nerve damage levels Table 3.14 Nerve damage levels Frankel level A B C D1 D2 D3 E Quantity 11 54 3.4.3 Nerve damage and the spinal canal narrow levels in each fracture type Table 3.16 Spinal canal narrow levels and nerve damage Narrow level - ND Not narrow < 50% ≥ 50% ND No ND ND No ND Fracture types Compression fracture 13 1 Burst fracture 23 Dislocation fracture 0 Total 21 26 p ND No ND 26 29 7 > 0.05 < 0.05 3.5 Evaluation of surgery results 3.5.1 Near result 3.5.1.3 Results of deformation correction 10 days after surgery Table 3.20 Results of deformation correction Deformation Fracture type Compression Group fracture Group Quantity 11 Smallest  2  12 14 Standard deviation      16 6.6 14.6 3.3 1.5 18 4.5 15.7 3.2 1.2 Biggest  10 10 Mean 18 Group Burst fracture Group Dislocation Group fracture 37 30 2 19 33 10 15 6.9 10.5 3.2 15 8.5 10.2 7.7 15 9.0 10.2 1.0 1.2 2.3 3.1 3.5.1.4 Results of neurological recovery 10 days after surgery Table 3.21 Results of neurological recovery Frankel – 10 days after surgery Total Bradford A B C D1 D2 D3 E level A 6 B 3 C 11 Before D1 1 surgery D2 D3 E 54 54 Total 6 63 89 3.5.2 Far results 3.5.2.2 Results of deformation correction in the final examination Table 3.23 Results of deformation correction Deformation Quantity Fracture types Compressio Group n fracture Group Group Burst fracture Group Dislocation Group fracture 11 37 30 Smallest Biggest  3 3  15 17 10  12 11 20 34 12 Mean   19 7.8 20 5.4 17 8.4 17 9.8 20 10.8  17.3 18.0 12.4 11.8 13.2 Standard deviatio n   3.5 1.5 3.2 1.0 5.1 2.5 7.6 2.4 1.3 3.9 3.5.2.3 Results of neurological recovery in the final examination Table 3.24 Results of neurological recovery Frankel – Bradford levels Before A Final examination A B C D1 D2 Total D3 E 19 surger y Total B C D1 D2 D3 E 4 2 3 2 54 71 3.5.2.4 Back pain Chart 3.19 Distribution rate of backache levels 3.5.2.5 Labor recovery Chart 3.20 Distribution rate of labor recovery levels 11 54 89 20 87 bands and the broken rate of screws 3.5.2.6 Number of fixed 100 80 60 40 20 Quantity screw Broken Chart 3.21 Number of fixed bands and the broken rate of screws CHAPTER DISCUSSION 4.2 Characteristics of vertebral fractures 4.2.1 Position of vertebral body injury The fracture rate at the thoracolumbar spine hinge vertebra and vertebra L1 is the highest This result is consistent with the anatomical characteristics of the spine segment (which is considered straight, kyphotic angle of the region 0⁰ - 10⁰), with the injury mechanism of longitudinal compression type and consistent with the study results of the local and foreign authors 4.2.2 Fracture types In our study, burst fracture accounts for 74,16%; compression fracture of 19,10% This rate is consistent with indirect trauma and thoracolumbar spine hinge vertebra injury accounts for the majority with the rate of 94,38% and 85,39%, respectively According to Benzel E C., the traumatic force acting in the direction of the vertical axis will be coaxial with IAR on the 21 thoracolumbar spine hinge vertebra, therefore burst fracture, compression fracture are more commonly seen 4.2.3 Vertebral fracture level, the cohesion of fractured pieces, height reduction of front column and kyphotic angle in the injured area in terms of each fracture type In our research, deformation was studied and evaluated for each fracture group and found that it depended on: the degree of height reduction in vertebral body, breaking degree of vertebral body, cohesion of fractured pieces, especially injury in the middle column This is consistent with McCormack's judgment However, there are other related factors such as the integrity of the posterior ligament complex, joint block lesions Thus, a full evaluation of the correlations between the factors in each fracture group has given us a more comprehensive view of deformation in spinal injuries as a basis for selecting an appropriate method for stabilizing and maintaining a stable structure in surgery To overcome the possible kyphotic complications, besides the correction, restoration of kyphotic angle of the area and height of the vertebral body, the restoration and conservation of the posterior ligament complex is necessary 4.2.4 Spinal canal narrow levels, causes and compressing positions Through the computerized tomography image of the fractured vertebra, we have realized that: compression fracture with low spinal canal narrows rate accounts for 17.65%; of which 100% of the spinal canal narrow is < 50% due to the posterior bending angle of the vertebral body at the ½ above position Burst fractures of spinal canal narrows group accounts for the majority, about 88.06%; of which narrow level ≥ 50% is about 49.25%; the reason is that fractured pieces accounts for the majority (96.6%) and compression at the position of ½ above accounts for the majority (84.7%) Group of dislocation fracture has 100% of spinal canal narrows; of which narrow level ≥ 50% makes up 60%, because the 22 vertebral body combines with broken bones/fractured pieces; compression position at ½ below accounts for 100% 4.3 Injury in the posterior ligament system On clinic and conventional X-ray image, it has suspicious injury signs of the posterior ligament system as a basis for magnetic resonance imaging to determine the lesions: large soft tissue injuries, increased distance between posterior spinal cord and kyphotic angle of ≥ 20º Dislocation fracture in the posterior ligament system accounts for the largest percentage (100%), burst fracture group is 14.93%, compression fracture is 23.53% All of these cases have a kyphotic angle of > 20º The posterior ligament complex has an effect on the angular bending distortion of the traumatic area Thefore, during surgery we have focused on preserving and restoring the posterior ligament complex, especially the ligament on the spinal cord and joints 4.4 Nerve damage In the study, we have evaluated the nerve damage in each fracture type, based on the degree of spinal canal compression and have found that: the compression fracture causes a lower rate of nerve damage (17.65%) and shows no relation to the spinal canal narrow levels, the cause of nerve damage may be due to stretch or arch effects mentioned by Benzel E.C.; burst fractures of vertebral body causing nerve damage accounts for 43,28% and 100% of spinal canal narrow, shows a relation between nerve damage and the spinal canal narrow levels; dislocation fractures causing nerve damage accounts for 60% , of which 100% have spinal canal narrows ≥ 50% 4.5 Surgery 4.5.1 Survey for surgical indication Via the survey on the LSC and TLICS scale, we have found that all indications have advantages and disadvantages, and it’s necessary to fully evaluate the most important traumatic characteristics: morphological damage, the posterior ligament system and nerve damage and the relationship between them At the same time, we mention all four fracture types and take 23 into account the characteristics of the fracture position when indicating However, the important goal of the indication is to offer the best choice for surgical method to make sure stable correction/fixation and effective decompression 4.5.4.3 Result of stable correction Considering the corection result and maintenance of angular bending deformation of the trauma area, we have realize that compression has variable amplitude for kyphotic angle and the reduction in the column in front of the fractured vertebra is stable during the process, it proves the correction effectiveness and stable fixation maintenance For burst fracture group, the corection result and maintenance of stable structure shows a higher variable amplitude for kyphotic angle but within the allowable limit For dislocation fracture, the injury on the posterior ligament system, moveable and immoveable joint system is quite high that damages the link system of spinal vertebra and make the fractured vertebra move, thus seriously affect the stable structure of the spine This causes difficulties in the correction and stable fixation of the injured vertebra Thus, during surgery we have used the steady foot bow screw system (short band type) to fix directly to the injured vertebral body to adjust maximum the sliding restoration and recover the stable structure, combine with restoration of ligaments on the spines As such, it makes sure of providing sufficient force and support for the screw system in the correction and fixation to restore and maintain the stable spinal structure This is the result of a combination of fixed configuration options, focusing on structural traumatic characteristics of each fracture type with preservation, restoration of joint block, the posterior ligament complex, especially ligaments on the spinal cord 4.4.4 Nerve recovery In this study we assessed nerve recovery at two points: 10 days after surgery and the final examination from the 12th month after the surgery (average follow-up time is 14.47 months) We found that 10 days after surgery there was no case 24 becoming more severe and 17 out of 35 cases with nerve damage recovered at least one Frankel degree, accounting for 48.57%, of which 12 cases recovered Frankel degree or totally recovered, accounting for 34.29% However, there were still 18 cases, accounting for 52.94% This is a positive predictive factor that demonstrates that the surgical approach takes an effect, contributing to the elimination of the risk of secondary nerve damage and to facilitate the recovery process At the last examination from the 12th month after surgery, we realized that the recovery was very clear and remarkable The total number of recovered cases was 27/35, accounting for 77.14%, the number of cases recovered at least two degrees Frankel compared to pre-surgery was 13, accounting for 37.14% and the number of cases fully recovered was 17, accounting for 48.57% Comparisons with the level of nerve damage before surgery showed significant meaningful differences However, there were still cases not recovering at all under Frankel scale (4 cases of Frankel A, Frankel B and Frankel C), accounting for 22,86% CONCLUSION Through the study of 89 patients experiencing the unstable lower thoracic and lumbar spinal fractures due to injury, such patients were indicated for a surgery to fix, correct and decompress by a posterior low band screw system combining with restoration and conservation of ligaments on the spinal cord, we draw two conclusions as below: Surgical injury characteristics, TLICS and LSC survey - The fracture rate at the thoracolumbar spinal vertebra accounts for the majority (about 85,39%), the fracture position is not equal and the difference is statistically significant Of which fracture at L1 has the highest rate of 46,07%; at L4 has the lowest rate (1,12%) - There are statistical difference at the fracture rates among three fracture types, of which burst fracture accounts for 75,28% 25 - There are statistical difference at the fracture rates among three fracture types in terms of angular bending at the injured area and reducing the height of anterior column Compression fracture (22,12 ± 2,78; 51,35 ± 2,28%); burst fracture (26,24 ± 3,87; 34,6 ± 7,32%); dislocation fracture (28,8º ± 5,26; 27 ± 5,7%) - The spinal canal narrow levels and fracture types has a correlation (p