Crossed Intralaminar Screws for Fusion of the Cervicothoracic Junction and the Thoracic Spine: The Experience in an Iberic Service with Case Series and Review of the Current Literature with Technique Description

The treatment of pathologies in the thoracic spine is a challenge. The periodic failure of pedicle screw insertion and anatomical variations make the search for an alternative to pedicle screws in thoracic spine surgery necessary. The interlaminar crossed screws is a well-known and secure method for fusion in cervical spine, and in thoracic spine there used to be insufficient clinical data to support this technique, until now. We demonstrate in an initial series of 10 cases treated with interlaminar fusion in association of other fusion techniques in the thoracic spine with good results. Objective: Intralaminar screws have been shown to be a biomechanical salvage technique in the thoracic spine, especially in long cervicothoracic, thoracic and thoracolumbar fixation. The goals of this article are to demonstrate our initial experience and the range of indications for thoracic crossed intralaminar screws. Methods: In this article we describe our initial series performed at S&#227o Teot&#243nio Hospital in Viseu, Portugal, and our results, and also provide a comprehensive review of the recent literature in the use of intralaminar crossed fixation.

Treatment of osteoporotic compression fracture of thoracic/lumbar vertebrae by kyphoplasty with SKY bone expander system

Objective： To investigate prospectively the effectiveness ofkyphoplasty with SKY bone expander system in treatment of compression fracture of thoracic/ lumbar vertebrae and correction of the deformity. Methods： Twenty-five patients with thoracic/lumbar vertebral osteoporotic compression fracture were admitted to our hospital between March 2007 and March 2008, and treated by kyphoplasty with SKY bone expander system. Patient＇s pain status was rated with Visual Analogue Scale （VAS） score system 1 day before and 1 hour, 48 hours, 6 months, 12 months after surgery. In addition, Rolland-Mor- ris and Oswestry disability questionnaires （RDQ and ODI） were used for survey 1 day before and 1, 6, 12 months after surgery. Pre- and post-operative vertebral heights and Cobb＇s angles were measured based on the X-ray films and statistically analyzed. Results： There were 27 fractured vertebrae in these 25 patients. After SKY kyphoplasty, the Cobb＇s angles （9.8°±9.76°） were significantly reduced compared with preoperative angles （17.18°±9.35°, P〈0.05）, and the average improve- ment rate was 39%. Patients＇ pain VAS scores were also greatly improved after operation （P〈0.05）. Moreover, postoperative RDQ and ODI scores were significantly smaller than preoperative values （P〈0.05）. Conclusions： Kyphoplasty with SKY bone expander system provides an effective method for treating thoracic/ lumbar vertebral osteoporotic compression fracture, with the advantages of small surgical wound and short duration. It can effectively recover the anterior and medial heights of fractured vertebrae （33% and 50%, respectively）, reduce the Cobb＇s angle, quickly alleviate pain and improve patients＇ quality of life in a relatively short time period.

Clinical observation on acupuncture at Jiaji(EX-B 2) points plus tuina in treating thoracic facet joint disorder

Objective： To observe the clinical effects of acupuncture at Jiaji （EX-B 2） points plus tuina manipulation for thoracic facet joint disorder, and get new clinical evidence for treatment of thoracic facet joint disorder. Methods： Totally 106 patients with thoracic facet joint disorder were randomly allocated into an observation group and a control group based on the random number table. Patients in the control group were treated by tuina manipulation, while those in the observation group were treated by acupuncture at Jiaji （EX-B 2） points before tuina manipulation. Patients in the two groups were treated once a day. The improvements of signs and symptoms and the efficacy were observed after 3 treatments. Results： After treatment, there were intra-group statistical differences in scores of 8 signs and symptoms in both groups （P〈0.01}; the score of each item in the observation group was lower than that in the control group, and there was statistical significance in the inter-group difference （P〈0.05）. The cure rate of the observation group was 50.9%, versus 26.4% in the control group, and there was a significant difference between the two groups （P〈0.05）. Conclusion： In treating thoracic facet joint disorder, acupuncture plus tuina manipulation can restore the biomechanical balance of thoracic vertebrae, fully maximized the combined effect, and significantly improve the clinical efficacy.

Radiographic verification of pedicle screw pilot hole placement in thoracic spine using Kirschner wires versus spiral wires

Objective: To evaluate the feasibility of the pedicle screw pilot holes placement in thoracic spine using the spiral wires as the guide pin. Methods: The pedicle screw pilot holes were drilled within the center of the pedicle and the lateral and medial pedicle walls were violated in 9 human dried thoracic vertebrae. Kirschner wires or spiral wires were separately placed in the holes, and then the posteroanterior and lateral radiographs were taken. The radiographs were evaluated by 3 experienced spine surgeons and 3 young orthopedists. After radiographs were shown to these observers, they combined the posteroanterior and lateral radiographs in each place and determined whether the pedicle screw pilot hole violated the pedicle cortex or not. The results were analyzed by a statistical software. Results: Sensitivity, specificity and accuracy of the method using spiral wires to detect pedicle pilot hole placement were significantly higher than those of using Kirschner wires. With a true posteroanterior radiograph, the sensitivity, specificity and accuracy of the method using spiral wires approximated or attained 100%. Conclusions: The method of intrapedicular pilot hole placement verification using spiral wires is effective for guiding the accurate placement of pedicle screws.

Clinical observation on acupuncture combined with tuina manipulation for thoracic facet joint disorder

Objective： To observe the clinical effect of acupuncture combined with tuina manipulation for thoracic facet joint disorder. Methods： A total of 93 eligible cases were randomly allocated into an observation group and a control group. Patients in the observation group （n=46） were treated with acupuncture combined with tuina manipulation, whereas patients in the control group （n=47） were treated with tuina manipulation alone. The treatment was done once a day, for a total of 3 times. Therapeutic efficacies were then evaluated according to scores on signs and symptoms. Results： After treatment, there were intra-group statistically significant differences in scores of eight signs and symptoms （all P〈0.01）; and the between-group differences were statistically significant in scores of eight signs and symptoms （all P〈0.05）. After three times of treatment, the recovery rate in the observation group was 54.4%, versus 25.4% in the control group, showing a statistical significance （P〈0.05）. Conclusion： Acupuncture combined with tuina manipulation can obtain better effects than tuina manipulation alone for thoracic facet joint disorder and is therefore worth further clinical application.

Mechanism of thoracolumbar burst fractures：a biomechanical study

OBJECTIVE: To investigate the mechanism associated with thoracolumbar burst fractures. METHODS: Stress distribution of the spine in the upright, flexion and extension positions was analyzed using a three-dimensional finite element model of the spinal motion segment. RESULTS: Stress concentration was noted at the pedicle and posterosuperior part of the vertebral body near the pedicle. CONCLUSION: Stress concentration of the spine may be implicated in the biomechanical mechanism underlying thoracolumbar burst fractures.

Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system： an analysis of 38 cases

Objective： To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non-randomized case-control study. Methods： Atotal of 38 consecutive non-randomized patients with type A thoracolumbar fractures, which had been stabilized posteriorly from December 2006 to March 2009, were examined retrospectively more than 9 months after surgery. Twenty-one patients had been treated conventionally with open pedicle screw fixation （OPSF） and 17 patients received minimally invasive treatment with Sextant percutaneous pedicle screw fixation （SPPSF）. As a method of evaluation, the incision size, the intraoperation and post- operative volume of blood loss, operation time, postoperative hospital stay, blood transfusion, the radiological assessment of the sagittal Cobb＇s angle, vertebral body angle and vertebral body height were recorded and compared. Results： All patients were followed up for 8-24 months （average 11.6 months）. There were significant differences in the incision size, surgical blood loss, surgical draining Joss, operation time, hospital stay after operation, blood transfusion, the proportion of antalgic supplement and postoperative incisional VAS between the two groups （P〈0.05）. Mean preoperative kyphotic deformity was 16.0° and improved by 9.3° after surgery in OPSF group, but 15.2° and 10.3° respectively in SPPSF group. Mean preoperative angle of the fractured vertebral body was 15.9°and improved by 7.9° after surgery in OPSF group, but 14.9° and 6.6° respectively in SPPSF group. Mean anterior vertebral body height （% of normal） was 67.3% before surgery and 95.8% after surgery, but 69.1% and 90.1% respectively in SPPSF group. Mean posterior vertebral body height （% of normal） was 93.3% before surgery and 99.5% after surgery, but 88.9% and 93.3% respectively in SPPSF group. Among the patients whose 9-month follow-up films were available, 3.0° ofkyphosis correction was lost in OPSF group, but 3.2° in SPPSF group. And 1.0°of the angle of the fractured vertebral body correction was lost in OPSF group, but 1.5°in SPPSF group. Then 3.0% of the anterior vertebral body height correction was lost in OPSF group, but 2.2% in SPPSF group. And 3.0% of the posterior vertebral body height correction was lost in OPSF group, but 2.5% in SPPSF group. The sagittal Cobb＇s angle, vertebral body angle and anterior height of the fractured vertebra were all significantly different in each group before and after operation （P〈0.05）. There were no significant differences in the postoperative sagittal Cobb＇s angle, vertebral body angle and the improvement of the vertebral body height and the kyphotic deformity correction between OPSF and SPPSF groups （P〉0.05）, but there was significant difference in the postoperative anterior height of the fractured vertebra between the two groups （P〈0.05）. Conclusion： The percutaneous pedicle screw fixation through the pedicle of fractured vertebra using Sextant system is a good minimally-invasive surgical therapeutic choice for patients with type A thoracolumbar fracture except for that the SPPSF has a little insufficiency in resuming the anterior height of the fractured vertebra compared with OPSF.

Comparison of three different surgical approaches for treatment of thoracolumbar burst fracture

Objective： The main treatment method used for thoracolumbar fractures is open reduction and in- ternal fixation. Commonly there are three surgical approaches： anterior, posterior and paraspinal. We attempt to compare the three approaches based on our clinical data analysis. Methods： A group of 94 patients with Denis type A or B thoracolumbar burst fracture between March 2008 and September 2010 were recruited in this study. These patients were treated by anterior-, posterioror paraspinal-approach reduction with or without decompression. The fracture was fixed with titanium mesh and Z-plate via anterior approach （24 patients）, screw and rod system via posterior approach （38 patients） or paraspinal approach （32 patients）. Clinical evaluations included operation duration, blood loss, inci- sion length, preoperative and postoperative Oswestry disability index （ODI）. Results： The average operation duration （94.1 min±13.7 rain）, blood loss （86.7 ml-20.0 ml）, length of incision （9.3 mm± 0.7 mm） and postoperative ODI （6±0.5） were significantly lower （P〈0.05） in paraspinal approach group than in traditional posterior approach group （operation duration 94.1 min±13.7 min, blood loss 143.3 ml±28.3 ml, length of incision 15.4 cm±2.1 cm and ODI 12±0.7） and anterior approach group （operation duration 176.3 min±20.7 min, blood loss 255.1 ml±38.4 mt, length of incision 18.6 cm±2.4 cm and ODI 13±2.4）. There was not statistical difference in terms of Cobb angle on radiographs among the three approaches. Conclusion： The anterior approach surgery is conve- nient for resection of the vertebrae and reconstruction of vertebral height, but it is more complicated and traumatic. Hence it is mostly used for severe Denis type B fracture. The posterior approach is commonly applied to most thoracolumbar fractures and has fewer complications compared with the anterior approach, but it has some shortcomings as well. The paraspinal approach has great advantages compared with the other two approaches. It is in accordance with the concept of minimally invasive surgery and can replace most posterior approach operations.

Paraspinal approach for thoracolumbar fracture

Objective： To explore the advantages and indications of the paraspinal approach by anatomical study and clinical application.Methods： The anatomical data and clinical practice of 27 cases were analyzed to explore the accurate approach between the paraspinal muscles and the structure of ambient tissues, as well as the results of clinical application of paraspinal approach. The operation time, blood loss, incision length, radiographic result （Cobb angle, height of anterior edge of the vertebrae） were compared with those in 24cases treated by traditional approach.Results： Complete exposure of the facets could be easily performed by identifying natural cleavage plane between the multifidus and Iongissimus muscles. The natural muscular cleavage was （1.47±0.23） cm lateral to the midline for females, and （1.64±0.35） cm for males at T12 level. The distance was （3.3±0.6） cm lateral to the midline for females,and （3.7±1.0） cm for males at L4 level. In paraspinal approach group, the operation time was （76.2±15.7） min, blood loss was （91.6±16.9） ml and incision length was （7.6±0.8） cm. In traditional approach group, the operation time was （121.4±19.6） min, blood loss was （218.7±32.3 ） ml and incision length was （17.4±2.1） cm. To compare paraspinal approach with traditional approach, the operation time, blood loss and incision length had statistical difference （P〈0.05） and the radiographic result （Cobb angle, height of anterior edge of the vertebrae） had no statistical difference （P〉0.05）.Conclusions： When the paraspinal approach is performed through natural cleavage plane between the multifidus and longissimus muscles, there are no wide muscular disinsertions, leaving the supraspinous and interspinous ligaments intact. The distance of natural cleavage to the midline is different at T12 and L4 planes. By this approach,the facet joints can be explored easily and completely, and a clear surgical field will be available for the placement of pedicle screws. As a minimally invasive approach, it can be widely used in thoracolumbar spine surgery.

The influence of the intervertebral disc on stress distribution of the thoracolumbar vertebrae under destructive load

Objective: To compare the influence of normal and degenerative discs on stress distribution of the thoracolumbar vertebrae under destructive load, explore the biomechanical background and clinical meaning and provide theoretical basis for clinical diagnosis and treatment. Methods: A mechanical model of thoracolumbar motion segment of normal and degenerative discs was built with a three dimensional finite element method and three stresses of vertical compression, compressive flexion and distractive flexion were comparatively analyzed. Results: With vertical compression and compressive flexion loads, the thoracolumbar motion segment of the normal disc showed that the central part of the upper and lower end plates of the vertebrae and the central part of the trabecular bone adjacent to the end plate were loaded with the most intensive stresses, meanwhile, the postero lateral part of the annulus fibrosus was concentrated with stresses. Degenerative disc showed that the stress distribution of the trabecular bone was relatively averaged, the stresses of the central part adjacent to the end plate were low, while at the same time, the stresses of the peripheral part were elevated relatively. With distraction flexion load, the stresses of the cortex bone, trabecular bone, end plate and annulus fibrosus of the thoracolumbar vertebrae of degenerative discs were low, meanwhile, the stresses of the posterior structure of the vertebral body were relatively elevated compared with that of normal discs. Conclusions: There is difference in influence between normal and degenerative discs on the stress distribution of the thoracolumbar vertebrae with destructive load. The transferring way of load is changed after disc degeneration.

Pedicle screw fixation against burst fracture of thoracolumbar vertebrae

Objective： To analyze the application of vertebral pedicle screw fixation in the treatment of burst fracture of thoracolumbar vertebrae. Methods： A total of 48 cases （31 males and 17 females, aged from 18-72 years, mean： 41.3 years ） with thoracolumbar vertebrae burst fracture were treated by pedicle screw system since January 2004. According to the AO classification of thoracolumbar vertebrae fracture, there are 36 cases of Type A, 9 of Type B and 3 of Type C. Results： All patients were followed up for 6-25 months （average 12 months ）, no secondary nerve root injury, spinal cord injury, loosening or breakage of pedicle screw were observed. The nerve function of 29 patients with cauda eqnina nerve injury was restored to different degrees. The vertebral body height returned to normal level and posterior process angle was rectified after operation. Conclusions： The vertebral pedicle screw internal fixation was technologically applicable, which can efficiently reposition and stablize the bursting fractured vertabrae, indirectly decompress canalis spinalis, maintain spine stablity, scatter stress of screw system, reduce the risk of loosening or breakage of screw and loss of vertebral height, and prevent the formation of posterior convex after operation.

Screw placement of pedicle of vertebral arch-pay great attention to segmental differences of the pedicle

Objective: To investigate appropriate ways for screw placement of pedicle of vertebral arch in the horizontal plane. Methods: Fifteen preserved thoracolumbar spine specimens (T 11 L 5) were used and divided into three groups at random. Firstly four anatomic parameters indicating screw positions in the horizontal plane were measured. Secondly the methods of Roy camille, Magerl, and authors’segmental differences were used to place successively the screws of the pedicles with 5 mm, 6 mm, and 7 mm in diameter. Coincidences between the drilling point, drilling direction and pedicle axis, and ruptures of the pedicle as well as the length of the screw in the vertebral body were observed. Results: Four anatomic parameters at various segments showed significant differences (P < 0.05 ). The drilling point by the Roy camille’s method deviated medial to pedicle axis in most segments, and its drilling direction did not coincide well with most E angles of the pedicles. The drilling point by Magerl’s method coincided relatively well with pedicle axis in lumbar vertebrae, but there were still some differences between its drilling direction and E angles of the pedicles. The method of segmental differences coincided the best with the pedicle axis. The lengths of screw in the vertebra were relatively long by both Magerl and segmental difference methods. When 5 mm diametral screw was used by the three methods, the rupture rate was very low. When 6 mm and 7 mm diametral screws were placed, the rupture rate was accordingly increased. Of the three methods, Roy camilles method showed a relatively high rupture rate, while the method of segmental differences a comparatively low rupture rate. Various degrees of rupture of the pedicle of vertebral arch were found at the juncture of the thoracic and lumbar vertebrae when 6 mm or 7 mm diametral screws was used by any screw placement method. In contrast, the rupture was seldom seen at the lower lumbar vertebrae when 7 mm diametral screws were used.Conclusions: The segmental difference method is proved to have the anatomic safety and screw biomechanical stability. It is appropriate to choose different diametral screws, different drilling points and directions according to different segments of the vertebra.

Value of multidetector spiral CT in diagnosis of acute thoracolumbar spinal fracture and fracture-dislocation

Objective: To investigate the diagnostic value of multidetector spiral CT (MSCT) in acute thoracolumbar spinal fracture and fracture-dislocation. Methods: CT imaging files of 152 consecutive traumatic patients with thoracolumbar fractures were retrospectively reviewed. MSCT scannings were performed with a collimation of 3-5 mm and a pitch of (5.5). The postprocessing included sagittal and coronal multiplannar reconstruction, and 3-D reconstruction.Results: There were 88 cases of compression fracture, 54 cases of burst fracture and 10 cases of fracture-dislocation. Transverse images of MSCT could visualize all fractures directly and determine whether spinal canal was intact. Postprocessing image was helpful in depicting the displacement of fragment and orientation of dislocation.Conclusions: MSCT plays an important role in diagnosis and management of acute thoracolumbar spinal fracture and fracture-dislocation.

Clinical manifestations and significance of post-traumatic thoracolumbar syringomyelia

Objective: To analyze the pathogenic mechanism and the clinical significance of post traumatic thoracolumbar syringomyelia through reviewing the clinical manifestations. Methods: The data of 15 patients (14 males and 1 female, aged from 28 to 56 years, with an average of 36 years) with post traumatic syringomyelia treated in our hospital from December 1997 to February 2002 were studied retrospectively. Two patients suffered from T 11 fractures, 7 from T 12 fractures and 6 from L 1 fractures. There were 12 patients with burst fractures and 3 with fracture dislocations. Anterior decompression, bone graft, bone fusion and internal fixation were made on 6 patients, posterior decompression, bone graft, bone fusion and internal fixation on 1 patient, and non surgical treatment on 8 patients. Results: Syringomyelia of the patients was diagnosed accurately with magnetic resonance imaging at 0.5 4 years after the original thoracolumbar fracture. The cavern was round in 6 cases, elliptic in 6 cases, and irregular in 3 cases. The patients also suffered from pain (80%), myodynamia attenuation in lower extremities ( 66.7 %), aggravated spasm ( 46.7 %), sensation loss or hypesthesia ( 46.7 %), decreased coordinate function of lower extremities (20%) and autonomic nerve symptom ( 6.7 %). Conclusions: Post traumatic thoracolumbar syringomyelia should be suspected if the patient has new neurological symptoms, such as myodynamia attenuation in lower extremities, after the neural function becomes stable for certain time.

Clinical study on abdominal acupuncture for osteoporotic vertebral compression fracture

Objective： To explore the efficacy of abdominal acupuncture in treating patients with osteoporotic vertebral compression fracture （OVCF）. Methods： Forty-five eligible OVCF patients were randomized into an abdominal acupuncture （AA） group, a body acupuncture （BA） group and a medication group according to the random numbers generated by the SPSS 22.5 version software, 15 subjects in each group. Patients in the medication group were intervened by Ossotide injection （intravenous injection）, Caltrate （oral administration）, Alfacalcidol （oral administration）, and Salcatonin injection （muscular injection）. In addition to the intervention given to the medication group, patients in the AA group additionally received acupuncture at Zhongwan （CV 22）, Xiawan （CV 20）, Qihai （CV 6）, Guanyuan （CV 4）, Shuifen （CV 9）, and Huaroumen （ST 24）; while patients in the BA group additionally received acupuncture at Jiaji （EX-B 2, superior and inferior to the affected area） points, Ashi points, Weizhong （BL 40） and Chengshan （BI. 57）. For the AA and BA groups, the acupuncture treatment was given once a day, 6 d per week, for 3 weeks in total. Prior to the intervention, and respectively after 1-week treatment, 2-week treatment and 3-week treatment, visual analogue scale （VAS） and Barthel index （BI） were adopted to evaluate pain degree and activities of daily living （ADL）. Results： After intervention, the VAS and BI scores were significantly changed in the three groups （P〈0.05）. Respectively after 2-week, 2-week and 3-week treatment, the VAS and BI scores in the two acupuncture groups were significantly different from those in the medication group at the same time point （P〈0.02）. After 2-week and 2-week treatment, the improvements of VAS and BI scores in the AA group were more significant than those in the BA group（P〈0.05）; after 3-week treatment, there was no significant difference in comparing the VAS score between the two acupuncture groups （P〉0.05）, but a significant difference was found in comparing the BI score （P〈0.05）. Conclusion： Abdominal acupuncture can produce a more significant effect in improving VAS and BI scores in OVCF patients than body acupuncture and pure medication treatment, and it＇s efficient and causes few sufferings.

Effect of posterolateral fusion on thoracolumbar burst fractures

Objective:To evaluate the efficacy and significance of posterolateral fusion in preventing failure of short-segment stabilization for the treatment of thoracolumbar burst fractures. Methods:Sixty patients with thoracolumbar burst fractures were included in the study. The patients were classified into two groups (n =30 in each group). In Group A, patients were treated in our hospital with short-segment instrumentation via posterolateral fusion with iliac bone. In Group B, patients were treated in other hospital with short-segment fixation without fusion. All cases came to our hospital for reexamination. There were 18 males and 12 females in Group A with a mean age of 42.3 years (range, 24 to 52 years) and 16 males and 14 females in Group B with a mean age of 41.5 years (range, 19 to 54 years). Radiographic (Cobb angle, kyphosis of the vertebral body, and sagittal index) and clinical outcomes (Low Back Outcome Score) were analyzed after an average follow-up of 16 months. Results:After operation, Cobb angle was reduced from 19.3°to 3.1°in Group A and from 19. 1°to 3. 3°in Group B (P>0.05).It was 5.9°in Group A and 11. 9°in Group B at the final follow-up (P < 0.01). Its average loss of correction was 2. 8°in Group A and 8. 6°in Group B. Average kyphosis of the vertebral body was reduced from 21.3°to 6.2°in Group A and from 21.7°to 7.4°in Group B (P > 0.05). It was decreased to 7.9°in Group A and 13.5°in Group B at the final follow-up (P < 0. 01). Its average loss of correction was 1.7°in Group A and 6.1°in Group B. Sagittal index was reduced from 21.3°to 3.6°in Group A and from 20. 5°to 3. 8°in Group B (P < 0.05). It was decreased to 5. 1°in Group A and 9. 8°in Group B at the final follow-up (P < 0. 01). Its average loss was 1.5°in Group A and 6.0°in Group B. In Group A, 73.3% of patients had an excellent result based on Low Back Outcome Score system, while that in Group B was only 43.3%. Conclusions:Posterolateral fusion is an effective measure to prevent implant failure, and decrease loss of correction, posttraumatic kyphosis and neurogical deficit during the treatment of thoracolumbar burst fractures. Short-segment fixation of thoracolumbar burst fractures without fusion obviously increases failure rate and it is not an optional procedure.

Current status and perspective of diagnosis and treatment of thoracolumbar fracture in China

Since the late 20th century owing to the improvement of spinal surgery techniques, the diagnosis and treatment of thoracolumbar fracture have been perfected more and more. Although the advent of modern spinal surgery in China was late, we have gained some advanced achievements owing to various international communications benefited from the open policy. Therefore, it is essential to evaluate the current status and perspective of diagnosis and treatment of thoracolumbar fracture. There are several issues we would like to discuss here.

Comparison of stress distribution of thoracolumbar vertebrae under forces with CT value

To provide a new method to estimate the effectiveness of thoracolumbar vertebral finite element model. Methods: A mechanical model of human thoracolumbar vertebrae motion segment was made using three-dimensional finite element method and the stress distribution of vertically compressed thoracolumbar vertebrae was analyzed, meanwhile, 20 patients with burst fracture of thoracolumbar vertebrae were tested by CT to calculated average CT value at ascertained different points of thoracolumbar vertebrae. The calculated results and effective stress at the same position were analyzed with straight line correlation. Results: The stress level of different position of thoracolumbar vertebrae under vertical compressive force was positively correlated with the correlative CT value, and the regressive style, Y= 214.028 + 45.268 X, r= 0.7386 , P< 0.05 (n=8) showed a statistical significance.Conclusions: To study mechanism of thoracolumbar vertebrae injuries under different forces has clinical significance.

Clinical study of a new approach to thoracolumbar surgery

Objective： The conventional approaches for treatment of thoracolumbar diseases require extensive surgical exposure, often leading to postoperative pain and morbidity. Thoracoscopic-assisted surgery in these regions usually requires an extended recovery period due to the placement of drainage. We developed an innovative retroperitoneal-extrapleural approach to thoracolumbar involvement by an extra-diaphragmatic technique using dedicated instruments. Neither incision nor reconstruction of the diaphragm was necessary. Exposure to the lateral part of the thoracolumbar vertebrae could be achieved without crus resection. This study is aimed to evaluate the clinical outcomes of this new surgical procedure. Methods： A total of 9 cases （5 cases of thoracolumbar fracture-dislocation, 1 each of spinal infection, tumor, thoracolumbar scoliosis and ossification of posterior longitudinal ligament） were subjected to the study. The average age of the patients was 52.3 years. The results were compared with the control group consisting of thoracoscopic surgery subgroup （5 patients, mean age 52.1 years） and conventional surgery subgroup （12 patients, mean age 61.3 years）. Results： Compared with the control group, the average period of bed confinement and mean intra- and postoperative blood loss decreased significantly. Pulmonary complications were avoided in all cases. The surgical time was shortened, postoperative pain was reduced, and early postoperative ambulation became possible. Conclusion： The diaphragm-preserving retroperitoneal-extrapleural approach that we developed is a valid minimally invasive alternative for the treatment of thoracolumbar diseases.