Correlation between the schanz screw insertion angle and the loss of kyphosis correction in thoracolumbar fractures / Correlação entre o ângulo de inserção do pino de schanz e a perda de correção da cifose em fraturas toracolombares / Correlación entre el ángulo de inserción del tornillo de schanz y la pérdida de corrección de la cifosis en fracturas toracolumbares

ABSTRACT Objective To compare the Schanz screw insertion angle and the loss of the regional kyphosis correction in thoracolumbar burst fractures following posterior short instrumentation surgery. Methods Patients with a thoracolumbar burst fracture between levels T11-L2 were divided into two groups (parallel and divergent) according to the angle formed between the Schanz screw and the vertebral plateau. Regional kyphosis was evaluated in preoperative, immediate postoperative and last follow-up radiographs. Results Of the 58 patients evaluated, 31 had a parallel assembly and 27 had a divergent assembly. When we analyzed the angle of kyphosis, no statistical difference was observed between the pre- and postoperative radiographs. However, a statistical difference in the last follow-up radiographs and in the final loss of the kyphosis correction was confirmed. Conclusion The insertion of Schanz screws with a divergent assembly presents better radiographic results with less loss of kyphosis correction angle when compared with the parallel assembly technique. Level of Evidence III; Retrospective cohort study.

RESUMO Objetivo Comparar o ângulo de inserção do pino de Schanz e os resultados da perda de correção da cifose regional nas fraturas toracolombares do tipo explosão após tratamento cirúrgico com instrumentação curta por via posterior. Métodos Os pacientes com fratura toracolombar do tipo explosão entre os níveis de T11-L2 foram divididos em dois grupos (paralelo e divergente) de acordo com o ângulo formado entre o pino de Schanz e o platô vertebral. Foi avaliada a cifose regional nas radiografias pré-operatória, pós-operatória imediata e do último acompanhamento. Resultados Dos 58 pacientes avaliados, 31 apresentaram uma montagem paralela e 27 uma montagem divergente. Ao analisarmos o ângulo da cifose, não se observou diferença estatística nas radiografias pré- e pós-operatória imediata. Porém, verificou-se uma diferença estatística nas radiografias do último acompanhamento e na perda final de correção da cifose. Conclusões A inserção do pino de Schanz com uma montagem divergente apresenta melhores resultados radiográficos com menor perda do ângulo de correção da cifose quando comparada com a técnica de montagem paralela. Nível de Evidência III; Estudo de coorte retrospectivo.

RESUMEN Objetivo Comparar el ángulo de inserción del tornillo de Schanz y los resultados de la pérdida de corrección de la cifosis regional en las fracturas toracolumbares del tipo explosión después del tratamiento quirúrgico con instrumentación corta por vía posterior. Métodos Los pacientes con fractura toracolumbar del tipo explosión entre los niveles de T11-L2 fueron divididos en dos grupos (paralelo y divergente) de acuerdo con el ángulo formado entre el tornillo de Schanz y la meseta vertebral. Fue evaluada la cifosis regional en las radiografías preoperatoria, posoperatoria inmediata y del último acompañamiento. Resultados De los 58 pacientes evaluados, 31 presentaron un montaje paralelo y 27 un montaje divergente. Al analizar el ángulo de la cifosis, no se observó diferencia estadística en las radiografías pre y postoperatoria inmediata. Sin embargo, se verificó una diferencia estadística en las radiografías del último acompañamiento y en la pérdida final de corrección de la cifosis. Conclusiones La inserción del tornillo de Schanz con un montaje divergente presenta mejores resultados radiográficos con menor pérdida del ángulo de corrección de la cifosis cuando comparada con la técnica de montaje paralelo. Nivel de Evidencia III; Estudio de cohorte retrospectivo.

Comparison of Percutaneous versus Open Pedicle Screw Fixation for Treating Unstable Thoracolumbar Fractures

PURPOSE: This study compared the clinical and radiological results between two groups of patients with percutaneous fixation or conventional fixation after hardware removal.MATERIALS AND METHODS: The study analyzed 68 patients (43 open fixation and 43 percutaneous screw fixation [PSF] 25) who had undergone fixation for unstable thoracolumbar fractures. The radiologic results were obtained using the lateral radiographs taken before and after the fixation and at the time of hardware removal. The clinical results included the time of operation, blood loss, time to ambulation, duration of the hospital stay and the visual analogue scale.RESULTS: The percutaneous pedicle screw fixation (PPSF) group showed better results than did the conventional posterior fixation (CPF) group (p<0.05) in regard to the perioperative data such as operation time, blood loss, and duration of the hospital stay. There were no significant differences in wedge angle, local kyphotic angle, and the ΔKyphotic angle on the postoperative plane radiographs between the two groups (p>0.05). There were no significant differences in the wedge angle and local kyphotic angle after implant removal (p>0.05) between the two groups as well. However, there were significant differences in the segmental montion angle (p<0.001), and the PPSF group showed a larger segmental motion angle than did the CPF group (CPF 1.7°±1.2° vs PPSF 5.9°±3.2°, respectively).CONCLUSION: For the treatment of unstable thoracolumbar fractures, the PPSF technique could achieve better clinical results and an improved segmental motion angle after implant removal within a year than that of the conventional fixation method.

Immediate stress and strain analysis of posterior pedicle screw fixation combined with different fusion cages in C5/6discectomy of simulated pig cervical vertebrae / 中国组织工程研究

BACKGROUND: Posterior decompression and pedicle screw fixation combined with interbody fusion is a method for the treatment of cervical vertebral degenerative lesions. There are few reports on the measurement of strain electricity in simulating C5/6 intervertebral disc fusion after pedicle screw removal. OBJECTIVE: To analyze stress and strain immediately after C5/6 discectomy, pedicle screw fixation combined with interbody fusion. METHODS: Eighteen fresh pig cervical specimens were randomly divided into three groups: Bone cage fusion group, PEEK fusion group, and titanium mesh fusion group (n=6). Each group simulated C5/6 discectomy and pedicle screw fixation, and then different fusion cages were used for interbody fusion. Before and after fusion, the resistance strain gauges were attached under the vertebral body at the position of pedicle screw fixation, at the edge of vertebral body at the fusion position of fusion cage, at the edge of adjacent vertebral body. The strain values of each sample were measured under the compression state by static resistance strain gauge. The stress values at each measurement point before and after fusion in posterior fixation with pedicle screws for cervical vertebrae in each group were calculated by material mechanics formula. RESULTS AND CONCLUSION: (1) Under the same load, the strain and stress of each measurement point in the titanium mesh fusion group were smaller than those in the bone cage fusion group and the PEEK fusion group, and the difference was significant (P < 0.05). (2) Under the same load, the strain and stress of each test point in the bone cage fusion group were larger than those in the PEEK fusion group, and the difference was significant (P < 0.05). (3) These results confirm that simulated C5 discectomy in vitro, posterior pedicle screw fixation and implantation of different fusion cages have different changes of stress and strain. The selection of appropriate interbody fusion cage can reduce the effect of stress concentration on adjacent segments.

Injury to upper cervical spine treated by posterior internal fixation without bone graft fusion / 中华创伤骨科杂志

Objective To investigate the clinical efficacy of treating injury to the upper cervical spine with posterior internal fixation without bone graft fusion.Methods Included in this retrospective study were 35 patients with upper cervical injury who had been treated at Department of Orthopedics,The Second Affiliated Hospital to Soochow University from June 2010 to August 2017.They were 21 males and 14 females with an average age of 44.1 years (from 26 to 56 years).They were all treated firstly by posterior occipitocervical internal fixation or internal fixation with atlantoaxial pedicle screws without bone graft fusion.The internal fixation was then removed after a solid bone union was confirmed by X-ray.The scores of Japanese Orthopedic Association (JOA),visual analogue scale (VAS),Neck disability index (NDI) and neck stiffness were used to evaluate the functional recovery of the upper cervical spine.We also observed the rotational range of the upper cervical spine using functional CT scan of C 1-C2.Results All the pedicle screws were successfully implanted after satisfactory intraoperative reduction,leading to no injury to the vertebral artery or spinal cord.All patients were followed up for an average of 18.1 months (from 7 to 28 months).At preoperation,post-implantation and final follow-up,the JOA scores were 6.5 ± 1.4,7.7 ± 1.5 and 16.1 ± 0.8 points,the VAS scores 6.1 ± 1.6,2.8 ± 0.8 and 1.1 ± 0.9 points,and the NDI scores 37.9 ± 2.6,20.3 ± 3.8 and 3.7 ± 1.7 points,showing significant improvements after internal fixation and after removal of internal fixation (P ＜ 0.05).Serious neck stiffness was observed in none of the 35 patients,mild neck stiffness in 12 patients and freedom from neck stiffness in 23 patients.The postoperative radiological analysis revealed fine fracture reduction and bony union in all.After 6 to 12 months the rotation of upper cervical spine was obviously improved and the left-to-right range of rotation of C 1-C2 was 35.4° ± 2.6° as revealed by functional CT scan.Conclusion For the middle aged and young patients with new injury to the upper cervical spine,the posterior occipitocervical internal fixation or internal fixation with atlantoaxial pedicle screws can be performed without bone graft fusion at the first stage and removal of internal fixation can be done at the second stage so that the atlantoaxial rotation can be preserved to ensure satisfactory clinical efficacy while bone union can be also ensured and pain reduced.

The research progress of posterior atlantoaxial internal fixation techniques / 医学研究生学报

Atlantoaxial instability or dislocation is a common upper cervical disease which can lead to serious outcomes including sensory and motor deficit or even sudden death. Therefore, active surgical intervention is often recommended. The most popular surgical procedure for atlantoaxial instability is posterior bone graft and internal fixation. Posterior stabilization techniques mainly include wiring techniques, interlaminar clamp fixation, C1-C2 transarticular screw fixation (Magerl technique), screw-plate systems, and screw-rod systems. Each technique has its advantage and shortcoming. The screw-rod systems, along with various modifications, has become the most popular internal fixation technique for posterior atlantoaxial stabilization in clinic. This article reviews the evolution, characteristics and new advancement of some prevail posterior atlantoaxial fixation techniques in purpose of giving a reference for surgeons to have a better understanding of posterior fixation techniques and make a reasonable choice in clinical practice.

Secondary posterior internal fixation after transoral anterior atlantoaxial release under 3D operative microscopy for irreducible atlantoaxial dislocation / 中华创伤骨科杂志

Objective To explore the clinical efficacy of secondary posterior internal fixation after transoral anterior atlantoaxial release under 3D operative microscopy for treatment of irreducible atlantoaxial dislocation.Methods From January 2014 to May 2016,12 patients with irreducible atlantoaxial dislocation were treated with secondary posterior internal fixation after transoral anterior atlantoaxial release under 3D operative microscopy in our hospital.They were 7 males and 5 females,with an average age of 37.1 years (from 25 to 54 years).The efficacy was analyzed in terms of their visual analogue scale (VAS),Japanese Orthopaedic Association (JOA) scoring,improvement rate of neurological function,American Spinal Injury Association (ASIA) grading,atlas-dens interval (ADI),space available for the cord (SAC) and cervicomedullary angle (CMA) before and one year after operation.Results The patients were followed up for more than one year.All the atlantoaxial joints obtained anatomic reduction.Their preoperative values of VAS (5.73 ± 1.36 points),JOA score (9.03 ± 2.12 points),ADI (8.34 ± 1.12 mm),SAC (9.53 ± 0.69 mm) and CMA (121.23°±4.32°) were significantly improved one year after operation (1.21 ±0.63 points,14.32±2.51 points,2.83 ± 0.36 mm,14.23 ± 1.22 mm and 153.53° ± 9.25°, respectively) (P ＜0.05).The improvement rate of neurological function increased gradually with the postoperative time,reaching 94.14％ ±5.11％ one year after operation.The postoperative ASIA grading was significantly improved too one year after operation (P ＜ 0.05).Conclusion Secondary posterior internal fixation after transoral anterior atlantoaxial release under 3D operative microscopy may lead to fine clinical efficacy one year after operation for patients with irreducible atlantoaxial dislocation.

Morphometric Study of C1 Pedicle and Feasibility Evaluation of C1 Pedicle Screw Placement with a Novel Clinically Relevant Radiological Classification in an Indian Population

STUDY DESIGN: A retrospective computed tomography (CT)-based morphometric study of 84 C1pedicles in an Indian population focusing on critical morphometric dimensions vis-a-vis C1 pedicle screw placement. PURPOSE: To determine the feasibility of C1 pedicle screw placement in an Indian population and propose a novel classification system for the same. OVERVIEW OF LITERATURE: At present, C1 pedicle screws are rarely used, and very few studies have focused on the feasibility of pedicle screw placement in terms of racial, gender, and ethnic variations in anatomical structures. There are no CT-based data on C1 pedicles that assess the feasibility of pedicle screw placement in the Indian population. METHODS: We measured C1 pedicle diameter on CT coronal scan images of 42 adult patients. Extramedullary height (EMH) and intramedullary height (IMH) were measured. We examined the differences between the right and left atlas pedicles and compared measures between males and females. These data were analyzed using significance tests. Based on the results, we propose a novel classification system, which we believe will help in determining the feasibility of C1 pedicle screw placement. RESULTS: Forty-two adult patients (84 pedicles) were examined. Average EMH and IMH were 4.48±0.91 and 0.86±0.77, respectively. Approximately, 32% of the C1 pedicles had bone thicknesses of <4 mm, 49% had IMH of <1 mm, and 38% had no pedicles. The average thickness in women was 4.21±0.93 mm, which was significantly thinner than that in men (4.73±0.81 mm, p=0.004). Right and left pedicles were not significantly different. CONCLUSIONS: Our data indicate that approximately one-third of the Indian population may not be suitable candidates for C1 pedicle screw placement. Caution should be exercised while placing type 1B and type 2 pedicles based on our proposed classification system.

Thoracolumbar burst fractures, short x long fixation: a meta-analysis / Fraturas toracolombares do tipo explosão, fixação curta x longa: uma metanálise / Fracturas toracolumbares tipo explosión, fijación corta x larga: un meta-análisis

ABSTRACT The number of fixed segments in the surgical treatment of thoracolumbar burst fractures remains controversial. This study aims to compare the results of short and long fixation in thoracolumbar burst fractures through a meta-analysis of studies published recently. MEDLINE and Cochrane databases were used. Randomized controlled trials and non-randomized comparative studies (prospective and retrospective) were selected. Data were analyzed with the software Review Manager. There was no statistically significant difference in the Cobb angle of preoperative kyphosis. Long fixation showed lower average measurements postoperatively (MD = 1.41; CI = 0.73-2.08; p<0.0001) and in the last follow-up (MD = 3.98; CI = 3.22-4.75; p<0.00001). The short fixation showed the highest failure rates (RD = 4.03; CI = 1.33-12.16; p=0.01) and increased loss of height of the vertebral body (MD = 1.24; CI = 0.49-1.98; p=0.001), with shorter operative time (MD = -24.54; CI = -30.16 - -18.91; p<0.00001). There was no significant difference in blood loss and clinical outcomes. The high rates of kyphosis correction loss with short fixation and the lower correction rate in the immediate postoperative period were validated. There was no significant difference in the blood loss rates because arthrodesis was performed in a short segment in the analyzed studies. The short fixation was performed in a shorter operative time, as expected. No study has shown superior clinical outcomes. The short fixation had worse rates of kyphosis correction in the immediate postoperative period, and increased loss of correction in long-term follow-up, making the long fixation an effective option in the management of this type of fracture.

RESUMO A quantidade de segmentos fixados no tratamento cirúrgico das fraturas toracolombares tipo explosão continua controverso. Este estudo tem como objetivo comparar os resultados da fixação curta e da longa nas fraturas toracolombares do tipo explosão, por meio de uma metanálise dos estudos publicados recentemente. Foram utilizadas as bases de dados MEDLINE e COCHRANE. Foram selecionados estudos controlados randomizados e estudos comparativos não randomizados (prospectivos e retrospectivos). Os dados foram analisados com o software Review Manager. Não houve diferença estatisticamente significante na medida do ângulo de Cobb da cifose pré-operatória. A fixação longa apresentou medidas médias inferiores no pós-operatório (MD = 1,41; IC = 0,73-2,08; p < 0,0001) e no último seguimento (MD = 3,98; IC =3,22-4,75; p < 0,00001). A fixação curta apresentou taxas de falha maiores (RD = 4,03; IC = 1,33-12,16; p = 0,01) e maior perda de altura do corpo vertebral (MD = 1,24; IC = 0,49-1,98; p = 0,001), com menor tempo operatório (MD = -24,54; IC = -30,16 - -18,91; p < 0,00001). Não houve diferença estatisticamente significante na perda sanguínea e nos desfechos clínicos. As taxas elevadas de perda da correção da cifose na fixação curta e a menor taxa de correção no pós-operatório imediato foram validadas. Não houve diferença estatisticamente significante quanto às taxas de perda sanguínea, porque a artrodese foi realizada em um segmento curto nos trabalhos analisados. A fixação curta teve menor tempo operatório, como esperado. Nenhum estudo demonstrou superioridade dos resultados clínicos. A fixação curta apresentou taxas piores de correção da cifose no pós-operatório imediato e maior perda da correção no seguimento a longo prazo, fazendo da fixação longa uma opção efetiva no manejo deste tipo de fratura.

RESUMEN El número de segmentos fijados en el tratamiento quirúrgico de las fracturas toracolumbares tipo explosión sigue siendo controvertido. Este estudio tiene como objetivo comparar los resultados de fijación corta y larga en las fracturas toracolumbares tipo explosión, a través de un meta-análisis de estudios publicados recientemente. Se utilizaron las bases de datos MEDLINE y COCHRANE. Se seleccionaron los ensayos controlados aleatorios y estudios comparativos no aleatorios (prospectivos y retrospectivos). Los datos fueron analizados con el software Review Manager. No hubo diferencia estadísticamente significativa en cuanto a la medida del ángulo de Cobb de la cifosis preoperatoria. Lar fijación larga mostró mediciones promedio más bajas en el postoperatorio (MD = 1,41, IC = 0,73-2,08; p < 0,0001) y en el último seguimiento (MD = 3,98, IC = 3,22-4,75; p < 0,00001). La fijación corta mostró las tasas de fracaso más altas (RD = 4,03, IC = 1,33-12,16; p = 0,01) y una pérdida mayor de la altura del cuerpo vertebral (MD = 1,24, IC = 0,49-1,98; p = 0,001), con un menor tiempo operatorio (MD = -24,54; IC = -30,16 - -18.91; p < 0,00001). No hubo diferencia significativa en la pérdida de sangre y los resultados clínicos. Se validaron las altas tasas de pérdida de corrección de la cifosis con la fijación corta y la menor tasa de corrección en el postoperatorio inmediato. No hubo diferencia significativa en las tasas de pérdida de sangre porque la artrodesis se realizó en un segmento corto en los estudios analizados. La fijación corta tuvo menor tiempo operatorio, como se esperaba. Ningún estudio ha demostrado resultados clínicos superiores. La fijación corta tuvo peores tasas de corrección de la cifosis en el postoperatorio inmediato y mayor pérdida de corrección en el seguimiento a largo plazo, por lo que la fijación larga es una opción efectiva en el manejo de este tipo de fracturas.

Clinical observation on the treatment of atlantoaxial dislocation based on the classification / 中国骨伤

<p><b>OBJECTIVE</b>To retrospectively analyze the surgical methods and its clinical effects and explore a clinical classification and treatment strategy for atlantoaxial dislocation(AAD).</p><p><b>METHODS</b>The clinical data of 89 patients with atlantoaxial dislocation were analyzed from September 2005 to September 2013. There were 49 males and 40 females, aged from 13 to 67 years with an average of 48.1 years. According to the reductive effects with preoperative cervical dynamic radiograph and high weight skeletal traction under general anesthesia, the dislocations were classified into three types:easy reduction type, hard reduction type and irreducible type. The patients with easy reduction type were treated with posterior screw rod internal fixation after manual reduction, while the patients with hard reduction type were treated with posterior screw rod fixation after high weight skeletal traction reduction under general anesthesia. The patients with irreducible type were treated with transoral atlantoaxial joint release or depression and posterior internal fixation and fusion. According to JOA scores to evaluate the neurological status and treatment outcome.</p><p><b>RESULTS</b>Thirty patients were classified as easy reduction type, 55 patients as hard reduction type, and 4 patients as irreducible type. The preoperative JOA score was 8.2±3.1 on average, while the postoperative score was 14.2±2.4. The improvement rate was 40.1% to 82.5% with an average of 62.5%. Eighty nine patients were followed up from 6 to 37 months with a mean of 17.3 months. Eighty two cases obtained anatomical reduction and 85 cases obtained bony fusion. One case complicated with hyponatremia after operation and 1 case combined with Guillain-Barre syndrome, 4 cases complicated with delayed union wounds, 1 case died of for respiratory failure 2 years after operation. No wound infections were found in the patients approach for transoral operation.</p><p><b>CONCLUSIONS</b>According to the cervical dynamic radiograph and high weight skeletal traction under general anesthesia to classify for atlantoaxial dislocation, and adopting well strategies to treat the patients, can achieve satisfactory effects.</p>

Clinical Outcomes of Posterior C2-C3 Fixation for Unstable Hangman's Fracture Compared with Posterior C1-C3 Fusion

OBJECTIVE: To verify the clinical outcomes of posterior C2-C3 fixation for unstable Hangman's fracture compared with posterior C1-C3 fixation. METHODS: Twenty four patients for unstable Hangman's fracture were enrolled between July 2007 and June 2010 in this study. Thirteen patients underwent posterior C2-C3 fusion and 11 patients underwent posterior C1-C3 fusion. Clinical outcomes were evaluated using Neck Disability Index (NDI) scores and Visual Analogue Scale (VAS) scores during preoperative and postoperative follow up period. Plain radiographs were obtained on postoperative 1 day, 1 week, and then at 1, 2, 6, and 12 months. CT was done at postoperative 12 months in all patients for evaluation of bone fusion. The mean period of clinical follow-up was 15 months. RESULTS: The mean ages were 43.3 years in C2-C3 group and 50.0 years in C1-C3 group. Mean follow-up period was 17.2 months in C2-C3 group and 16.3 months in C1-C3 group. VAS scores and NDI scores in C2-C3 group were much less than those in C1-C3 group at each follow-up period. The differences of VAS score and NDI scores between C2-C3 and C1-C3 groups at each follow-up period were statistically significant (p<0.001) by paired T-test. Solid Bone fusion was confirmed in all cases at the final follow-up. CONCLUSION: C2-C3 group showed better clinical and biomechanical results than C1-C3 group in terms of axial pain and disability of neck.

Comparison of Short Segment and Long Segment Posterior Instrumentation of Thoracolumbar and Lumbar Bursting Fractures at Load Sharing Score 7 or Above

STUDY DESIGN: A retrospective comparative analysis of the short-segment and long-segment posterior fixation in thoracolumbar burst fractures that are 7 points or above in load-sharing score was performed. OBJECTIVES: The purpose of this study is to demonstrate the appropriate level of fixation by comparing the results of short-segment and long-segment posterior fixation. SUMMARY OF LITERATURE REVIEW: There is general consensus that short-segment fixation should be done in thoracolumbar burst fractures that are 6 points or less in load-sharing classification. There is some controversy regarding whether short-segment or long-segment fixation should be done in thoracolumbar burst fractures that are 7 points or above in load-sharing classification. MATERIALS AND METHODS: From 1998 through 2008, 32 patients with thoracolumbar burst fractures above 7 points in load-sharing classification had been operated with short-segment (1 segment above and 1 segment below: 23 patients) or long-segment (2 segments above and 1 segment below: 9 patients) transpedicular screw fixation at the author's institution. They were divided by two groups (group I: short-segment fixation, group II: long-segment fixation). The mean age of patients was 49.2 years old and the mean follow-up period was 2.4 years (1-7 years). In preoperative and postoperative simple radiographs, the bony unions, breakages or loosening of implants were assessed, and the losses of correction angle and anterior vertebral body height were measured. RESULTS: In all cases, non-union or loosening of implants were not observed. There was 1 screw breakage in short-segment fixation group during the follow up period, but bony union was obtained at final follow-up. The mean score of load sharing classification was 7.3 in Group I and 7.1 in Group II, and there was no significant difference between two groups. (p>0.05) The mean anterior vertebral body height loss was 5.3% in Group I and 3.6% in Group II and the mean loss of correction angle were 4.72 in Group I and 3.38 in Group II. There was no significant difference between the two groups for both. (p>0.05) CONCLUSIONS: There was no significant difference in radiologic parameters between two groups. Short-segment fixation could be used successfully in selected cases of thoracolumbar burst fractures that are 7 points or above in load-sharing classification.

Comparison of Surgical Outcomes in Thoracolumbar Fractures Having 6 or Less Scored by Load-Sharing Classification Based on Posterior Fusion Level

PURPOSE: The aim of this study is to decide the optimal level of fusion with comparing the results between the short segment fusion and long segment fusion treated with pedicle screw instrumentation, including fractured vertebra in thoracolumbar junctional fractures. MATERIALS AND METHODS: From February 2000 to November 2009, fifty three patients with junctional fracture of thoracolumbar spine were treated with pedicle screws and posterior fusion at our hospital. They were divided into two groups, the short segment group and long segment group. Preoperatively, immediate postoperative and last follow-up lateral radiological evaluation was done by measuring the correction and loss of segmental kyphosis, wedge angle, body compression rate and instrumented vertebra angle. In addition, operation time and amount of intraoperative bleeding were measured. RESULTS: There were no significant differences of statistical analysis regarding the radiological variables between the two groups, especially the loss of corrected segmental kyphosis, wedge angle, body compression rate and instrumented vertebra angle (p>0.05). However, operative time in the short segment group (234 minutes) was shorter than the long segment group (284 minutes), and there was statistical significance (p=0.002). CONCLUSION: We recommend the short segment transpediculr instrumentation one level above and one level below, including the fractured vertebra for thoracolumbar junctional fracture with 6 points or less of the load-sharing score.

Results of Combined 360-Degree Fusion versus Posterior Fixation Alone for Thoracolumbar Burst Fractures / 대한신경손상학회지

OBJECTIVES: To identify the better option of treatment, we compared the surgical results and efficacy of combined anterior-posterior approach versus posterior fixation alone. METHODS: During a 10 years period from 2002 to 2011, 111 patients with thoracolumbar burst fracture was surgically managed at our institute. 25 patients were managed by a combined anterior-posterior surgery and 86 patients were managed by posterior fusion alone. Radiographs were repeated at 3, 6, 12 and 24 months after operation. Radiologic outcome was evaluated by measuring Kyphotic angulation and vertebral height and the clinical outcome was evaluated by visual analogue scale (VAS) score comparison. RESULTS: The average Cobb's angle difference between immediate post operative and last follow up was 15.0degrees in combined 360-degree fusion group and 7.5degrees in posterior surgery alone group. A corrections of vertebral body height between immediate post operative and last follow up was 2.27 mm in 360-degree fusion group while 0.59 mm in posterior fixation group. The VAS score decreased from 8.4 to 2.2 after post operation 24 months in 360-degree fusion group and the posterior surgery alone group decreased 9.3 to 6.2 after post operation 24 months. CONCLUSION: The combined anterior-posterior approach resulted in less deterioration of the kyphotic angle postoperatively and improvement of vertebral height (sagittal index). Clinical outcome was also better in the combined group.

Comparison of Posterior Fixation Technique and Anterior-Posterior Fixation Technique in Subtalar Arthrodesis / 대한족부족관절학회지

PURPOSE: Subtalar arthrodesis has been the gold standard for the painful subtalar joint disorders. Successful subtalar arthrodesis requires fusion of the 3 facet joints. The purpose of the study is to compare the clinical outcome of the posterior fixation (P2) and anterior-posterior (A1P1) fixation technique for subtalar arthrodesis which enhance anterior and middle facet fixation. MATERIALS AND METHODS: The study is based on the 20 feet (19 patients) of the subtalar arthrodesis utilizing cannulated screws from September 2006 to September 2009 with at least 1-year follow-up. Two fixation techniques were utilized for the subtalar arthrodesis: 1) posterior fixation only (P2, 7 feet, 35%) and 2) anterior-posterior (A1P1) fixation method (13 feet, 65%). Visual Analog Scale Pain (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score (maximum: 94 points), the time for returning to daily living and the patient satisfaction were also evaluated. RESULTS: Average follow-up period were 13.2 months (12-3 mo). The AOFAS score improved from preoperative average 45 (0-68) to 81.6 (62-94), while VAS score was decreased from average 8.0 (3-10) to 1.8 (0-5) at final follow-up. Ninety-five percent of the patients were satisfied with surgery. All the patients returned to daily living at average 7.2 months (2-15 mo) post-surgery. Radiographically, 2 techniques both showed 100% fusion of the posterior compartment of the subtalar joint. Postoperative complications were 1 case of low grade infection and 1 case of sural nerve neuralgia. CONCLUSION: The subtalar arthrodesis using A1P1 fixation technique showed better fusion rate of the anterior compartment of the subtalar joint compared to P2 fixation technique although the 2 techniques both showed similar favorable clinical outcome. Therefore the A1P1 fixation technique is found to be a viable option to address chronic painful subtalar joint disorders to enhance the anterior compartment fixation.

The Impact on Clinical Results by Sagittal Imbalance in Posterior Fixation for Thoraco-lumbar Burst Fractures

PURPOSE: Evaluate the effects of sagittal imbalance on the clinical outcomes in thoracolumbar burst fractures. MATERIALS AND METHODS: We evaluated 11 patients who had received posterior fixation for unstable burst fractures. Radiologic assessment including the compression ratio, focal kyphotic angle and sagittal balance were obtained. The clinical outcomes were assessed by ODI, VAS and SF-36. We subdivided the patients into sagittal balance and imbalance group, and compared with clinical outcomes. The relationship between radiologic and clinical outcomes was examined using correlation analysis. RESULTS: The radiologic assessment were changed on preoperative and postoperative as follows: mean compression ratio: 15.2%, 4.9%, mean focal kyphotic angle: 43.2degrees, 20.9degrees. The mean sagittal balance was 11.5 cm. The mean score of VAS, ODI, Physical and Mental Component Summary of SF-36 were 3.7, 45.8, 43.3 and 39.8, respectively. The ODI was significantly higher in sagittal imbalance group, and SF-36 was significantly higher in sagittal balance group (p<0.05). The VAS was correlated with compression ratio and focal kyphotic angle. The ODI and Mental Component Summary of SF-36 were correlated with sagittal imbalance. CONCLUSION: Sagittal balance effects on the functions of spine, surgical treatment should be carefully considered with unstable burst fractures.

The Use of Pedicle Screw-Rod System for the Posterior Fixation in Cervico-Thoracic Junction

OBJECTIVE: In cervico-thoracic junction (CTJ), the use of strong fixation device such as pedicle screw-rod system is often required. Purpose of this study is to analyze the anatomical features of C7 and T1 pedicles related to screw insertion and to evaluate the safety of pedicle screw insertion at these levels. METHODS: Nineteen patients underwent posterior CTJ fixation with C7 and/or T1 included in fixation levels. Seventeen patients had tumorous conditions and two with post-laminectomy kyphosis. The anatomical features were analyzed for C7 and T1 pedicles in 19 patients using computerized tomography (CT). Pedicle screw and rod fixation system was used in 16 patients. Pedicle violation by screws was evaluated with postoperative CT scan. RESULTS: The mean values of the width, height, stable depth, safety angle, transverse angle, and sagittal angle of C7 pedicles were 6.9 +/- 1.34 mm, 8.23 +/- 1.18 mm, 30.93 +/- 4.65 mm, 26.42 +/- 7.91 degrees, 25.9 +/- 4.83 degrees, and 10.6 +/- 3.39 degrees. At T1 pedicles, anatomic parameters were similar to those of C7. The pedicle violation revealed that 64.1% showed grade I violation and 35.9% showed grade II violation, overall. As for C7 pedicle screw insertion, grade I was 61.5% and grade II 38.5%. At T1 level, grade I was 65.0% and grade II 35.0%. There was no significant difference in violation rate between the whole group, C7, and T1 group. CONCLUSION: C7 pedicles can withstand pedicle screw insertion. C7 pedicle and T1 pedicle are anatomically very similar. With the use of adequate fluoroscopic oblique view, pedicle screw can be safely inserted at C7 and T1 levels.

The Surgical Effect of Posterior Fixation Suture in Incomitant Strabismus

PURPOSE: To know the surgical effect and the indication of posterior fixation suture in incomitant strabismus. METHODS: From January 2003 to October 2004, posterior fixation sutures were used in five patients with strabismus after orbital wall fracture and in three patients with high AC/A accommodative esotropia. Using Worth 4-dot tests, we compared the amount of incomitant deviation before and after surgery. RESULTS: The mean decrease in deviation after surgery was 7.8+/-2.6PD(P=0.04) in patients with strabismus after orbital wall fracture, and 11.3+/-4.2PD in those with high AC/A ratio accomodative esotropia. CONCLUSIONS: The posterior fixation suture was effective in reducing the amount of incomitant deviation occurring in cases of strabismus after orbital wall fracture and cases of high AC/A accommodative esotropia.

The Posterior Fixation of Thoracolumbar Burst Fracture using Pedicle Screws and Caudal Offset Sublaminar Hooks / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVES: We analyzed the clinical results of thoracolumbar burst fractures, managed by posterior fixation of 2 segments above and 1 segment below, using an offset sublaminar hook. SUMMARY OF LITERATURE REVIEW: Mono-segment fixation above and below the injured vertebra, using posterior pedicle screw fixation, has the benefit of saving the uninjured mobile lumbar segment in thoracolumbar junction burst fracture patients. However, in a severely comminuted vertebral body, mono-segment fixation may not prevent loss of correction and metal failure. Options for such cases are additional anterior column support or long segment fixation, including 2 segments above and 1 below the injured vertebra. Instead of fixing 2 segments below the fracture level, fixation of one segment below, using the offset sublaminar hook, can save the uninjured segment, especially in the upper lumbar segment, with greater fixation strength than mono-segmental screws only. MATERIAL AND METHOD: The study included eleven patients with a thoracolumbar junction burst fracture, which underwent posterior fixation using pedicle screws in 2 segments above and 1 segment below, aided by an offset sublaminar hook. The mean follow-up period was 30.7 months (range, 24 to 58 months). Radiographs taken at follow-up were evaluated for implant loosening, correction loss, change in pedicle screw angle, and loss of vertebral height, adjacent segment instability and junctional degenerative change. The clinical results were collected in out-patient department. RESULTS: No implant loosening was noted. No case showed adjacent instability, acceleration of junctional degenerative change at the lower end of lumbar segment or hook dislodgement. Also, there were no junctional area related symptoms. CONCLUSION: For posterior surgery of thoracolumbar burst fractures, this construct, fixing 2 segments above and 1 segment below injured vertebra, aided by an offset sublaminar hook, was satisfactory in maintaining fracture reduction, and showed no instability or acceleration of degeneration on adjacent segnents.

Treatment of Thoraco-Lumbar Bursting Fractures According to Load-Sharing Classification

PURPOSE: To determine optimal levels of posterior fixation in thoraco-lumbar bursting fractures according to the Load-sharing classification. MATERIALS AND METHODS: From Aug. 1999 to Aug. 2003, 50 patients who had been operated with the posterior fixation in one-body thoraco-lumbar bursting fracture were selected. They were divided into two groups, group I, 6 points and below in the Load-sharing score and group II, 7 points and above. And also, each groups subdivided into two subgroups, A (short segment fixation including below and above one body) and B (long segment fixation including below and upper two body). So patients subdivided into I-A, I-B, II-A, II-B. Change of the corrected kyphotic angle was measured and compared with each subgroups. RESULTS: The loss of the corrected kyphotic angle was measured average 1.7degrees in group I and 4.1degrees in group II, and there was significant difference between two groups (p>0.05). The loss of the corrected kyphotic angle in the subgroups was average 1.8degrees in I-A, 1.6degrees in I-B, 3.5degrees in II-A and 4.9degrees in II-B. And there was significant difference statistically in I-A and II-A (p>0.05). CONCLUSION: In the thoraco-lumbar bursting fracture with 6 points and below of the Load-sharing score, the fixation of the short segment is a useful method. But in the fracture with 7 points and above, the fixation of the short segment is not enough, and these findings be required the further evaluation for some cause of the loss of corrected angle and treatment modalities including the fixation of the long segment.

Preliminary Report of Temporary Posterior Instrumentation in Stable Thoracolumbar Burst Fractures / 대한척추외과학회지

STUDY DESIGN: A prospective study of posterior instrumentation without fusion for the stable thoracolumbar fracture. OBJECTIVES: To confirm vertebral body collapse by roentgenography and computerized tomography after removing posterior instrumentation at 6 months postoperatively in stable thoracolumbar burst fractures. SUMMARY OF LITERATURE REVIEW: Many authors have reported that vertebral body collapse occurs after instrumentation removal. MATERIALS AND METHOD: Sixty patients admitted between March 1999 and March 2001 with thoracolumbar junction fractures were included. Patients were divided into 3 groups: Group I - the Conservative management group (20 patients), Group II - Reduction and posterior fixation with fusion group (20 patients), Group III - Reduction and temporary posterior fixation group (20 patients). The patients were aged between 21 and 49 years (mean 38), and the follow-up period exceeded 1 year (mean 13.3 months). We studied vertebral height, kyphotic angle, disc height and facet hypertrophy by roentgenography, and the continu-ity of the anterior cortical connection, cavity formation, sclerotic bone formation and new bone formation by CT. RESULTS: The loss of vertebral height was 7.9% (from 21.5 to 29.4%) in Group I, 3.7% in Group II (preop 35%, postop 12.7%, postop 1Yr. 16.4%), and 3.5% in Group III (preop. 35.2%, postop 5.6%, postop 1Yr. 9.1%). Loss of angulation was 4.2degrees (from 9.6 degrees to 13.8 degrees) in Group I, 3.0 degrees in Group II (preop 15.3 degrees, postop 7.2 degrees , postop. 1Yr. 10.2 degrees), and 3.0 degrees in Group III (preop 14.6 degrees , postop. 5.9 degrees , postop 1Yr. 8.9 degrees). Loss of disc height was not statistically different for the 3 groups. Degenerative changes of the posterior facet were seen 3 patients of Group I, 11 patients of Group II, and in 5 patients of group III. On CT scan of Group III, all cases showed cavity formation and sclerosis ,and continuity of the anterior cortical connection and of new bone formation into the cavity were seen in 18 cases. CONCLUSIONS: Vertebral body collapse were not observed by roentgenography by computerized tomography after removing the posterior instrumentation at 6 months postoperatively in stable thoracolumbar burst fractures.