Feasibility of a novel type of complex anterior cervical fixation by using Mimics software / 中国骨伤

OBJECTIVE@#To investigate the feasibility of mimics software in analyzing a new type of complex anterior cervical fixation -- anterior transpedicular screw fixation+zero notch internal fixation.@*METHODS@#From January 2021 to September 2022, 50 normal pedestrians who underwent cervical spine CT scanning were selected for C1-C7 segment scanning, including 27 males and 23 females, aged from 25 to 65 years old with an average of (46.0 ± 9.0) years old. The dicom format is exported and engraved into the CD, and use the mimics software to perform 3D reconstruction of each segment. A simulated screw is placed on the image according to the critical value of zero notch screw (head and tail angle 44°, internal angle 29°). The position of zero notch screw in each segment is observed to determine the feasibility of anterior transpedicular screw fixation plus zero notch internal fixation.@*RESULTS@#For the upper zero notch screws the three-dimensional images of the cervical spine across all 50 subjects within the C3-C7 segments demonstrated safe position, with no instances of intersection with ATPS. For the lower zero notch screw, in C3-C4 and C4-C5, 4 out of 50 subjects are in the safe position in the three-dimensional images of cervical vertebrae, and 46 cases could achieve secure screw placement when the maximum caudal angle is(32.3±1.9) ° and (36.1±2.2) °, respectively. In C5-C6 and C6-C7 segments, no lower zero notch screws intersected with ATPS, and all screws are in safe positions.@*CONCLUSION@#Lower cervical anterior pedicle screw fixation plus zero notch internal fixation can achieve successful nail placement through the selected entry point and position.

Comparative study between 3D guide plate assisted and free-hand insertion of anterior cervical transpedicular screw / 中国骨伤

OBJECTIVE@#To compare accuracy of anterior cervical pedicle screws between assist of rapid prototyping 3D guide plate and free-hand insertion, and evaluate the safety of two methods.@*METHODS@#Eight adult cervical cadaver specimens after formaldehyde immersion, including 4 males and 4 females, aged 32 to 65(40.3±5.6) years old. After X-ray examination to exclude bone damage and deformity, 4 of them (3D guide plate group) randomly selected were for CT scan to obtain DICOM format data, and the data was imported into Mimics software for model, designed the ideal entry point and nail path for anterior cervicaltranspedicular screw (ATPS). After obtaining the personalized guide plate of the nail channel, it was exported as STL data, and the individual guide plate was printed by rapid prototyping and 3D printing technology. In turn, with the assistance of 3D guide plates, one-to-one personalized ATPS screws were placed on the four lower cervical cadaver specimens. Another 4 (free-hand group) lower cervical cadaver specimens were implanted with ATPS screws using free-hand technique. All specimens were performed CT thin-layer scanning and three-dimensional reconstruction after operation. The Tomasino method was used to evaluate the safety of the screws on the CT cross-sectional and sagittal images, to determine whether there was a cortical puncture of the lower and inner edges of the pedicle. According to the CT rating results, gradeⅠandⅡwere safe, and grade Ⅲ- Ⅴ were dangerous.And the accuracy of screws was recorded and analyzed between two groups.@*RESULTS@#Two screws were inserted in each segment from C@*CONCLUSION@#The 3D printing rapid prototyping guide plate assisted insertion of the anterior cervical pedicle screw can significantly improve the accuracy and safety, and provide a theoretical basis for further clinical application.

Safety and feasibility of a new 3D printing template designed for bilateral anterior cervical transpedicular screws placements / 中国组织工程研究

BACKGROUND: Anterior cervical transpedicular screws placement technique provides nice mechanical stability and is of very promising application prospects. However, the technology is difficult to operate and has a high risk, and has not been widely used. OBJECTIVE: To design a new three-dimensional (3D) printing template for bilateral anterior cervical transpedicular screws placements and assess its feasibility and safety in anterior cervical pedicle screw placement. METHODS: Six cadaveric cervical specimens, including three males and three females, were used in this experiment. Data of thin layer CT scanning of the specimens were saved in DICOM format and then imported into Mimics 17.0 software. Following 3D reconstructions of the cervical spine, guiding holes for C3-C7 bilateral anterior cervical transpedicular screws trajectories were designed; pedestals for the guiding holes were then designed via reversely thickening the bony structure of the anterior and 1/2 superior-anterior surface of vertebral body, and 1/2 anterior joint surface of bilateral processus uncinatus. Practical objects of the templates were obtained via 3D printing and were then used for guiding bilateral anterior cervical transpedicular screws replacements from C3 to C7. CT scanning was conducted again and the accuracy of anterior cervical transpedicular screws replacements was evaluated from sectional CT images. The difference of deviational angles on axial plane (α1, α2) and sagittal plane (β1, β2) between real and simulated trajectories were compared in Mimics 17.0 software. RESULTS AND CONCLUSION: (1) A total of 60 anterior cervical transpedicular screws were successfully inserted; 57 screws were completely located in pedicles and were judged as grade 0, representing an accuracy of 95.0%. The other three anterior cervical transpedicular screws perforated from pedicles, including grade 1 perforation in two screws (3.3%) and grade 2 perforation in one screw (1.7%). (2) By comparing real and simulated trajectories, the medical and lateral deviational angles were (0.867±0.787)° and (0.783±0.792)°, respectively (P > 0.05); the cephalad and caudal deviational angles were (1.362±1.380)° and (1.314±1.300)°, respectively (P > 0.05). (3) With the help of the 3D printing template designed in this study, bilateral anterior cervical transpedicular screws replacements could be smoothly carried out at high inserting safety.

Biomechanical study of the stability of subaxial cervical anterior transpedicular screw fixation for three-column injury / 中国骨伤

<p><b>OBJECTIVE</b>To compare the stability of subaxial cervical anterior transpedicular screw(ATPS) fixation and three traditional fixations for three-column injury.</p><p><b>METHODS</b>Six specimens of cervical spine were prepared. After measurememt of the range of motion(ROM) in intact state, the specimens were made into three-column injury models. The models were reconstructed with an anterior cervical cage, and stabilized by ATPS, anterior plate(AP), anterior plate + lateral mass screw(AP+LMS) and posterior transpedicular screw(PTPS). The ROM of the models in the four states were measured, and the results of data were compared after standardization.</p><p><b>RESULTS</b>The normalized ROM of ATPS state in flexion-extension, lateral bending, axial rotation were(77.17±4.75)%, (82.00±2.61)%, (83.17±2.23)%, which were significant small than those in intact state(<0.05). The normalized ROM of AP state in flexion-extension, lateral bending, axial rotation were(119.67±7.42)%, (116.33±7.53)%, (112.67±5.99)% , which were significant larger than those in intact state(<0.05). The normalized ROM of AP in all directions were significant larger than those of ATPS(<0.05). There was no significant difference between normalized ROM of PTPS state and those of ATPS state in flexion-extension and lateral bending(>0.05). The normalized ROM of PTPS state in axial rotation was(6.83±2.48)% and was significant larger than that of ATPS state(=0.009). The normalized ROM of AP+LMS state in flexion-extension was(68.50±2.43)%, which was significant smaller than that of ATPS state(=0.003). There was no significant difference between the normalized ROM of AP+LMS state and those of ATPS state in lateral bending and axial rotation(>0.05).</p><p><b>CONCLUSIONS</b>Subaxial cervical three-column injury model reconstruction by ATPS can provide the adequate primary stability, of which biomechanics property is superior compared to AP and PTPS, and is similar to that of AP+LMS. It can be applied to the patients with no need to decompression and reduction through posterior approach.</p>

Experimental study on rigidity effect of 3 kinds of different internal fixation at upper thoracic spine / 重庆医学

Objective To compare the rigidity at upper thoracic spine among the anterior transpedicular screw-plate system (ATPSPS),posterior transpedicle screw-rod system (PTPSRS) and anterior vertebral body screw-plate system (AVBSPS).Methods Twelve embalmed cadaver specimens were divided into three groups.The specimens in each group were randomly allocated to use the above 3 different internal fixation devices for conducting fixation.The stiffness of each specimen on the directions of axial compression,flexion and extension,and left and right lateral bending was detected under original status.All specimens conducted the simulated corpectomy of T2 (damage status).Then the rigidity on various directions was re-detected on the damage status.The corresponding internal fixation system was selected for conducting the install and fixation according to the grouping results.The intra-group and inter-group rigiditieson different directions were compared amongoriginal status,damage status and after internal fixation.Results The rigidities on different directions under original and damage statushad no statistical difference among various groups (P＜0.05).After conducting fixation in each group,the rigidity after fixation on different directions had statistically significant difference among groups(P＜0.05).The stiffness of anterior flexion in the ATPSPS group was greater than that in the other two groups (P＜0.05).The rigidity of axial compression and extension in the PTPSRS group was greater than that in the other two groups,the difference among groups was statistically significant (P＜0.05).The stiffness of lateral bending in the AVBSPS group was smaller than that in the other two groups,the difference was significant (P＜0.05),but the difference between the other two groups had no statistical significance (P＞0.05).Conclusion The rigidity of ATPSPS in all directions is higher than that of AVBSPS.The anterior flexion rigidity is greater than PTPSRS,and the axial compression and extension rigidity are less than PTPSRS,but the lateral bending rigidity is equivalent to PTPSRS.

Imaging measurement of circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles and its application analysis / 第二军医大学学报

Objective To measure the circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles on computed tomography (CT) images, providing a reference for accurate anterior cervical pedicle screws. Methods CT scanning was performed in 10 normal lower cervical vertebrae from fresh cadavers, and the coronal and sagittal reconstructed images were obtained. The images were then opened in AutoCAD-2007 software to perform quantitative measurement (accuracy was 0. 1 mm) using the “dimaligned function” of dimension menu, and measurement parameters included the thicknesses of superior, medial, inferior and lateral cortex of anterior entrance of pedicle (SAE. MAE. IAE and LAE. respectively), and thicknesses of superior, medial, inferior and lateral cortex of anterior half of pedicle (SPA, MPA, IPA and LPA, respectively). Results Average thicknesses of SAE. MAE. IAE. LAE, SPA, MPA. IPA, and LPA at left and right side from Q to C7 were (1. 9 + 0. 6) and (1. 9 + 0. 5) mm, (1. 9 + 0. 7) and (1.9+0. 4) mm. (2.4 + 0. 6) and (2. 4 + 0. 5) mm, (0. 9 + 0. 5) and (0. 9 + 0. 6) mm, (2. 3 + 0. 9) and (2. 3 +0. 7) mm, (2. 1 + 0. 5) and (2. 1 + 0. 6) mm, (2. 2+0. 8) and (2. 2+0. 7) mm, and (1. 0 + 0. 7) and (1. 0 + 0. 6) mm, respectively. There was no significant difference in same measurement parameter between left and right sides at same cervical level (P>0. 05). Single factor random block analysis of variance found LAE and LPA were significantly thinner than the other 6 parameters of the same side of same cervical vertebra (all P0. 05). Conclusion LAE and LPA are the thinnest among the 8 measurement parameters from C3 to C7, which suggests LAE and LPA have the weakest resistance to exotic force if resistance strength to exotic force is parallel to cortex thickness. We should avoid locating close to LAE when finding anterior entrance or close to LPA when inserting anterior cervical pedicle screws.

The development and evaluation of individualized templates to assist transoral C2 articular mass or transpedicular screw placement in TARP-IV procedures: adult cadaver specimen study

OBJECTIVES: The transoral atlantoaxial reduction plate system treats irreducible atlantoaxial dislocation from transoral atlantoaxial reduction plate-I to transoral atlantoaxial reduction plate-III. However, this system has demonstrated problems associated with screw loosening, atlantoaxial fixation and concealed or manifest neurovascular injuries. This study sought to design a set of individualized templates to improve the accuracy of anterior C2 screw placement in the transoral atlantoaxial reduction plate-IV procedure. METHODS: A set of individualized templates was designed according to thin-slice computed tomography data obtained from 10 human cadavers. The templates contained cubic modules and drill guides to facilitate transoral atlantoaxial reduction plate positioning and anterior C2 screw placement. We performed 2 stages of cadaveric experiments with 2 cadavers in stage one and 8 in stage two. Finally, guided C2 screw placement was evaluated by reading postoperative computed tomography images and comparing the planned and inserted screw trajectories. RESULTS: There were two cortical breaching screws in stage one and three in stage two, but only the cortical breaching screws in stage one were ranked critical. In stage two, the planned entry points and the transverse angles of the anterior C2 screws could be simulated, whereas the declination angles could not be simulated due to intraoperative blockage of the drill bit and screwdriver by the upper teeth. CONCLUSIONS: It was feasible to use individualized templates to guide transoral C2 screw placement. Thus, these drill templates combined with transoral atlantoaxial reduction plate-IV, may improve the accuracy of transoral C2 screw placement and reduce related neurovascular complications. .

Clinical and Radiological Outcomes of Segmental Spinal Fusion in Transforaminal Lumbar Interbody Fusion with Spinous Process Tricortical Autograft

STUDY DESIGN: A retrospective study. PURPOSE: To investigate clinical and radiological outcomes when using spinous process as a tricortical autograft for segmental spinal fusion in transforaminal lumbar interbody fusion (TLIF). OVERVIEW OF LITERATURE: Interbody spinal fusion is one of the important procedures in spinal surgery. Many types of autografts are harvested at the expense of complications. Clinical and radiographic results of patients who underwent TLIF with intraoperative harvested spinous process autograft in Prasat Neurological Institue, Bangkok, Thailand, were assessed as new technical innovation. METHODS: Between October 2005 to July 2009, 30 cases of patients who underwent TLIF with spinous process tricortical autograft were included. Clinical evaluations were assessed by visual analog scales (VAS) and Prolo functional and economic scores at the preoperation and postoperation and at 2 years postoperation. Static and dynamic plain radiograph of lumbar spine were reviewed for achievement of fusion. RESULTS: Initial successful fusion time in lumbar interbody fusion with spinous process tricortical autograft was 4.72 months (range, 3.8-6.1 months) postoperation and 100% fusion rate was reported at 2 years. Our initial successful fusion time in lumbar interbody fusion was compared to the other types of grafts in previous literatures. CONCLUSIONS: The use of intraoperative harvested spinous process tricortical autograft has overcome many disadvantages of harvesting autograft with better initial successful fusion time (4.72 months). VAS and Prolo scores showed some improvement in the outcomes between the preoperative and postoperative periods.

The feasibility of the anterior reverse transpedicular screw (ARTPS) fixation at upper thoracic spine / 中国脊柱脊髓杂志

Objectives: To verify the feasibility and safety of the anterior transpedicular screw(ATPS) fixation of the upper thoracic spine (T1-T4) through the radiological anatomy study on the cadaveric specimens. Methods: The upper thoracic spine thin-section CT data of 40 cases were collected from the radiology de-partment′s database(20 males and 20 females, aged from 18 to 68 years, the mean age was 39.7 years). The data of OPW(outer pedicle width), OPH(outer pedicle height), PAL(pedicle axis length), TPA(transverse section angle), SPA(sagittal section angle), DTIP(distance of transverse intersection point) and DSIP(distance of sagittal intersection point) of each pedicle were measured on the transverse and sagittal sections through the axis of each pedicle. The data were recorded and statistically analyzed. 10 upper thoracic spine(C7-T6) specimens of adults(5 males and 5 females, with unknown ages), with no damage to their appearance, the costovertebral joints and paravertebral soft tissue were completely retained. Then simulate surgical operations were done on the cadaveric specimens based on the obtained data. Screws were implanted anteriorly by free hand. After that, the specimens accepted X-ray fluoroscopy and CT scan. At last, the screws were removed, the speci-mens were sawed along the transaction and sagittal section of the screw channel. Then the success rate of the screw placement was evaluated according to Rao′s worn out classification standard of pedicle screws. Results: From T1 to T4, the OPW decreased from 8.14mm to 3.47mm; the OPH increased from 6.89mm to 10.29mm; the TPA decreased from 32.96° to 11.64°; the DTIP increased from 1.80mm to 5.50mm; the SPA increased from 104.95° to 115.74°; the DSIP increased from 5.95 to 8.76mm; the PAL changed irregularly, from 32.95 to 35.96mm. The pedicle diameters of T3 and T4 were too small to implant ATPS, but the ARTPS can be implanted successfully. The diameter of ATPS was about 4.0mm; the length of ATPS was about 35mm. The diameter of ARTPS was about 5.0mm; the length of ARTPS was about 35mm. 80 pedicle screws were implanted anteriorly, according to Rao′s worn out classification standard of pedicle screws, the fine rate was 90%. The internal walls of 7 pedicles were broken by screws of less than 2mm and no compression to the spinal cord. The internal walls of 5 pedicles were broken of 2 to 4mm, 1 at T1, 1 at T3 and 3 at T4, with varying degrees of spinal cord compression. The internal walls of 2 pedicles were broken of greater than 4mm, 1 at T2 and 1 at T4, with serious spinal cord compression. The external wall of 1 pedicle was broken at T2. Conclusions: The ATPS techniques at T1, T2 and the ARTPS techniques at T3, T4 are feasible, but the safety and clinical practice and further research is needed.

Management of Lumbar Pyogenic Spondylitis with Posterior Decompression and Interbody Fusion Using Transpedicular Screws / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to assess the efficacy of posterior decompression and interbody fusion with posterior instrumentation in treating lumbar pyogenic spondylitis. MATERIALS AND METHODS: Twenty-one patients with lumbar pyogenic spondylitis who underwent posterior decompression and lumbar interbody fusion with posterior fixation were reviewed. Clinically infection control (CRP normalization time) and rehabilitation were investigated. And radiologically, timing of achievement of fusion and changes of sagittal alignment were investigated. RESULTS: Infection was controlled successfully without any recurrence and breakage of instrument. Stable interbody fusion was achieved in all cases within 6 months. Postoperative interval to achieve normal CRP was 28.7 (10-64) days. Ambulation was started on 5.8th (2-19) day. Sagittal angle was 12.3 degrees before operation, became more lordotic to 16.4 degrees, but decreased to 11 degrees at final follow-up. Final sagittal alignment was almost same with the preoperative status. CONCLUSION: By achieving favorable results clinically and radiologically, posterior decompression and interbody fusion seemed to be an effective method in management of lumbar pyogenic spondylitis.

Unilateral vertebral plate decompression, interbody fusion and pedicle screw fixation in treatment of lumbar disc berniation / 第二军医大学学报

Objective:To explore the application and efficiency of unilateral vertebral plate decompresaion,interbody fusion and pedicle screw fixation in treatment of lumbar disc herniation. Methods1From Feb. 2006 to Feb. 2008,24 patients underwent unilateral vertebral plate decompression,interbody fusion and pedicle screw fixation. The patients were followed up for one year and the following data were recorded:operation time,estimated blood loss,duration of hospital-stay,short-term and medium-term clinical outcome. Results1 All patients had their low back pain and/or lower extremity radicular pain improved during the one year follow-up. The last follow-up showed that the numbers of patients with Oswestry Disability Index( ODI) P0-PS were 5 , 11, 6, 2,0, and 0, respectively. The clinical outcomes determined by modified JOA criteria showed that 18 patients had excellent outcomes,4 had good outcomes,and 2 had fair outcomea,with the excellent and good outcomes occupying 91. 67%. Conclusion1 The unilateral fixation can be used in patients with lumbar disc herniations who need lumbar spinal fusion. The medium-term outcomes is satisfactory.

The Effect of Vertebral Wedge Angle to the Change of Kyphotic Angle by the Posterior Instrumentation Method in Thoracolumbar Spine Fracture / 대한척추외과학회지

STUDY DESIGN: Retrospective study OBJECTIVES: To examine the effect of transpedicular screw fixation on fractured vertebrae about the vertebral wedge angle (VWA) after posterior instrumentation of the thoracolumbar fracture, determine the effect of reduced VWA on the change in the Kyphotic angle (KA), and minimize loss of reduction of KA. SUMMARY OF THE LITERATURE REVIEW: Maintenance of the KA of a thoracolumbar fracture after surgery is important for the radiologic and functional outcome. MATERIALS AND METHODS: Forty patients, who had undergone posterior instrumentation in a thoracolumbar fracture between February 2006 and February 2008 and followed-up for more than one year, were enrolled in this study. The patients were divided into two groups according to transpedicular screw fixation (Group A) or not (Group B) including fractured vertebrae. The evaluation was performed by measuring the changes in the KA and VWA taken after the injury, immediate after surgery and 1 year after surgery. RESULTS: There was correlation between groups A (transpedicular screw fixation on fractured vertebrae) and B (no transpedicular screw fixation on the fractured vertebrae) regarding the correction of the VWA and the loss of correction KA, (p<0.05). CONCLUSIONS: Reduction of the VWA is an important factor for preventing reduction loss of the KA, and transpedicular screw fixation including fractured vertebrae would help reduce the VWA. Therefore, the operator must pay attention to the increase in VWA to maintain the KA through short segment transpedicular screw fixation including fractured vertebrae.

Metal Failure in patients with Short-segmental Pedicle Screw Fixation and Fusion for Degenerative Lumbar Disease: Comparison Monoaxial with Polyaxial Screw / 대한척추외과학회지

STUDY DESIGN: Retrospective study OBJECTIVE: To evaluate the factors affecting metal failure and screw loosening of short-segmental (1- or 2-segmental) monoaxial or polyaxial screw fixation for degenerative lumbar disease. SUMMARY OF LITERATURE REVIEW: There was a report on metal failure and screw loosening in short-segmental monoaxial and polyaxial screw fixation in degenerative lumbar disease. MATERIALS AND METHODS: This study examined 227 cases who underwent short-segmental transpedicular screw fixation and vertebral fusion for a degenerative lumbar. RESULTS: Metal failure of transpedicular screws was detected in 6 cases, 3 each in groups A and B. Screw loosening occurred in 16 and 43 cases in group A and B, respectively. Both groups had a similar incidence of spinal stenosis with instability and spondylolisthesis. The failure rate and screw loosening according to the fusion level was also similar. The failure and screw loosening rates was higher in the cases who did not undergo PLIF than in the cases who underwent PLIF but the difference was not statistically significant. CONCLUSION: The metal failure and screw loosening rates after transpedicular screw fixation and spinal fusion procedures for degenerative lumbar diseases using monoaxial screws and polyaxial screws were similar.

Reconstruction of Spinal Alignment with Total Laminonectomy and Cervical Transpedicular Screws Techniques Applied in Acute Multi-segments Spinal Cord Injury / 中国康复理论与实践

@#Objective To assess the efficiency of total laminectomy and transpedicular screw placement techniques and a thoroughly decompression with a three column fixation device on the early cervical spine cord injury.Methods 27 patients were operated successfully with total cervical laminectomy through transpedicular screw techniques.Precise measurements of all cervical spines were made by postoperative CT scan of pedicle dimensions,angulation,and offset relative to the lateral mass boundaries.And meanwhile,cortical integrity and neurovascular injury were then assessed by obtaining postoperative computed tomography scans of each patient.Results Using manual techniques,220 pedicles were instrumented and all the cases were followed up between three to twenty-four months.The postoperative gradations were obviously better than the preoperative evaluation.Regardless of the technique used,the vertebral artery was the structure most likely to be injured.Conclusion Insufficient correlation between different surgeons' assessments of surface landmarks attests to the inadequacy of screw insertion techniques in the cervical spine based on such specific topographic.At the early stage of cervical spinal cord injury,using total laminonectomy decompression through cervical screws techniques to reconstruct spinal alignment could improve the prognosis of patients.

Post-traumatic Atlantoaxial Rotatory Dislocation in an Adult Treated by Open Reduction and C1-C2 Transpedicular Screw Fixation

Atlantoaxial rotatory dislocation (AARD) is an uncommon disorder of childhood in which clinical diagnosis is generally difficult and often made late. It is very rare in adults because of the unique biomechanical features of the atlantoaxial articulation. We report a case of post-traumatic AARD in an adult. Reduction was difficult to obtain by skull traction and gentle manipulation. Therefore, the patient was treated surgically by an open reduction, transpedicular screw fixation, and posterior C1-2 wiring with graft. The normal atlantoaxial relation was restored with disappearance of torticollis. Postoperatively, the patient remains neurologically intact and has radiographic documentation of fusion. Atlantoaxial transpedicular screw fixation can be one of the treatment options for the AARD.

Radiolucent Zones Surrounding Transpedicular Screws After Lumbar Spinal Instrumented Fusion / 대한척추외과학회지

STUDY DESIGNS: A retrospective study for radiographic and clinical assessment. OBJECTIVES: To clarify the clinical significance of the radiolucent zones surrounding transpedicular screws that occasionally appears following lumbar spinal instrumented fusion. SUMMARY OF LITERATURE REVIEW: that the formation of radiolucent zones surrounding pedicular screws are significantly frequent after transpedicular fixation. MATERIALS AND METHOD: 88 cases, age 50 or older, which underwent lumbar spinal fusion with transpedicular screws, between January 1999 and December 2002, were included in this investigation. The postoperative radiographs of all patients were analyzed for radiolucent zones around the transpedicular screws. These radiolucent zones were evaluated in relation the number of fusion levels, the existence of osteoporosis, and the fusion status and satisfaction rates. RESULTS: Radiolucent zones were observed in 30 cases (34%, 30/88), 13 (43%, 13/30) of which disappeared during the follow-up period. The average number of fixation levels in the cases with and without radiolucent zones were 2.33 (range 1-4, SD 0.94) and 1.74 (range 1-4, SD 0.82), respectively. Osteoporosis was found to accompany 43.3 and 20.7% of the cases with and without radiolucent zones, with the latter cases showing a statistically significant higher fusion rate and greater patient satisfaction. CONCLUSION: Radiolucent zones, a frequent finding following pedicle screw fixation, resulted in less favorable outcomes. Surgeons should be alert to radiolucent zones and their transformation during follow-up. Methods for improving the stability of the interface between the pedicle screw and vertebral bone will require further research.

Comparison of the Result of Lumbar Posterolateral Bone Fusion using Autogenous Bone Graft with Allobone Graft

OBJECTIVE: The purpose of this study is to analyze clinical outcome of lumbar spinal fusion with autobone graft and with allobone graft as an additional autograft extender. METHODS: Fifty two patients who underwent lumbar posterolateral arthrodesis for degenerative lumbar diseases between February, 1998 and October, 2000 were evaluated. Arthrodesis was performed by transpedicular screw fixation. We used autogenous bone graft in 32 cases (Group A) and allobone graft in 20 cases (group B). Post operative radiographs were obtained to review the resorption of graft bone and the evidence of fusion. A modified Lenke scale was used to assess the status of the fusion. RESULTS: There were 17 men and 35 women. Mean follow up period was 12 months. According to the modified Lenke scale, spinal bone fusion rate was 93.75% in the group A and 85% in the groub B. CONCLUSION: Lumbar spinal fusion using allobone graft is favorably good compare to autobone graft.

A Case Report of Missed Cervicothoracic Fracture-Dislocation in Plain Radiographs / 대한척추외과학회지

A complete fracture dislocation at the cervicothoracic junction is rare and accompanied by severe spinal cord injury. This region is difficult to image with plain radiography, and to immobilize with external orthosis due to the biomechanical forces exerted in this transitional portion of the spinal column. We experienced a rare case in 52-year-old male victim of a car accident. He sustained paraplegia, and complained of dyspnea and neck pain of 10 days duration at another hospital. The delayed clinical rediagnosis was a C6 and 7 spinous process fracture and a cervicothoracic fracture dislocation, with complete transection of spinal cord, which was based on a clinical examination, simple radiography, CT and MRI. Skeletal traction was immediately applied, followed by a posterior pedicle screw to stabilize the spine and secure the grafts. Rehabilitation was initiated and the dysphagia and dyspnea, due to aspiration pneumonia, were improved, but no neurologic recovery was made after the 1st postoperative year.

Posterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement in the treatment of dorsal and lumber spinal tuberculosis / 中国康复理论与实践

@#ObjectiveTo evaluate the clinical effectiveness of posterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement in the treatment of dorsal and lumber spinal tuberculosis. MethodsFrom March 1996 to July 2000,posterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement procedures were used in 62 patients suffering from dorsal and lumber spinal tuberculosis in our department,48 of them were involved in a longitudinal study follow-up for a mean of 3.6(1.5-5.5)years postoperatively. ResultsAll patients showed successful posterolateral bone graft fusion. Among 38 cases of Pott's paraplegia, 30 were completely recovered,5 were partly recovered,the rate of recovery was 92.1%. The average immediate postoperative correction of kyphosis angle was 29.1°,the average loss of correction was only 3.2°at final follow-up.ConclusionsPosterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement procedure were found helpful in strengthening the stability of the spine in dorsal and lumber spinal tuberculosis, providing successful interbody fusion and recovery of Pott's paraplegia, correcting the kyphosis, and preventing progression of kyphosis.

Instrument-Related Complications Following Lumbar Transpedicular Screw Fixation

OBJECTIVE: Transpedicular screw fixation systems are coming into wide use as an effective adjunct to lumbar spinal fusion procedures. However, there are some problems concerning hardware failure. In this report, we present an analysis of instrument-related complications following lumbar transpedicular screw fixation. METHODS: Lumbar spinal fusion using a transpedicular screw has been performed between 1995 and 2000 in 298 patients. We retrospectively investigated the complications related to screws and/or rods, which have been used in lumbar spinal fusions. RESULTS: The 262 patients(87.9%) who had undergone the surgery were satisfied with the results of their operations. The wound infection rate was 4.0%(n=12). Neural injuries occurred in 4 patients(1.3%); one patient was related to decompressive procedure and the others were related to instrumentation. The unsatisfactory screw placement occurred in 3.8%(60 of 1,582 screws placed). Forty-nine screws(81.7%) were misplaced in lateral direction in a total of 60 unsatisfactorily placed screws. Screw fractures occurred in 5(1.7%) patients, and the overall fracture rate was 0.3%(5 of 1,582 screws placed). Rod fractures occurred in 3(1.0%) patients and the overall fracture rate was 0.5%(3 of 596 rods placed). The breakage was usually apparent in the late stage of the clinical course, as seen on follow-up radiographs. CONCLUSION: We believe that failure of arthrodesis and multilevel fusion are the predisposing factors of instrument failure. The authors conclude that to minimize the complications following transpedicular screw fixation, it would be necessary to make a precise insertion of the transpedicular screw with adequate bone fusion.