Clinical application of 3D-printed drill guiding template in pedicle screw insertion in subaxial cervical spine / 中国脊柱脊髓杂志

Objectives:To explore the safety and accuracy of subaxial cervical pedicle screw(CPS)insertion assisted with optimized 3D-printed drill guiding template(DGT).Methods:A retrospective study was conducted to analyze the clinical data of 42 patients aged 32-74 years(50.1±9.8 years)who underwent posterior cervi-cal pedicle screw intemal fixation between August 2016 and October 2022.The patients were followed up for 13-25 months(19.6±3.2 months).They were divided into two groups of guiding template group(n=22)and free-hand group(n=20)according to the method of pedicle screw insertion.In the guiding template group,the sub-axial CPSs insertions were assisted with 3D-printed DGT,designed individually for each patient based on the design scheme of an optimized pedicle drill guiding template,and the patients consisted of 12 males and 10 females,among which 6 patients were with cervical spine injury or spinal cord injury,9 were with ossifica-tion of posterior longitudinal ligament(OPLL),5 were with intraspinal tumor,and 2 were with cervical spondy-lotic myelopathy.In the free-hand group,the subaxial CPSs were inserted with free hand according to the cervical parameters such as pedicle angle and diameter on the CT images measured before operation,and the patients consisted of 10 males and 10 females,among which 4 patients were with cervical spine injury or spinal cord injury,10 with OPLL,5 with intraspinal tumor,and 1 with cervical spondylotic myelopathy.There were no significant differences in sex,age,disease,and preoperative visual analogue scale(VAS)score and Japanese Orthopaedic Association(JO A)score between the two groups(P＞0.05).The operative time,intraopera-tive blood loss,and postoperative 12 months of VAS and JOA scores were recorded and compared.CT scan was performed at 1 week after operation on cervical spine,and the accuracy of pedicle screw placement was evaluated in accordance with Kaneyama's evaluation method:Grade 0,screw was contained in the pedicle;Grade 1,screw penetrated pedicle＜50％of the screw diameter;Grade 2,screw penetrated pedicle＞50％of the screw diameter;Grade 3,screw completely penetrated the pedicle.Grades 0 and 1 were considered accurate placement,and grades 2 and 3 were considered misplacement.The perioperative complications were recorded for each patient in the two groups.Results:The operative time,intra-operative blood loss in guiding template group(102.2±16.1min,89.3±17.7mL)were statistically less than those in free-hand group(142.8±20.9min,133.3±34.0mL)(P＜0.01).A total of 216 CPSs were placed:118 in the guiding template group,including 90 screws of grade 0,22 screws of grade 1,5 screws of grade 2,1 screw of grade 3,with an accuracy rate of 94.9％(112/118);And 98 in the free-hand group,including 48 screws of grade 0,36 screws of grade 1,10 screws of grade 2,and 4 screws of grade 3,with an accuracy rate of 85.7％(84/98).The accuracy rate of pedicle screw insertion was significant higher in the guiding template group than that in the free-hand group(P＜0.05).No major neurovascular complications nor internal fixation loosening or breakages were observed in two groups of patients.At 12 months after operation,the VAS score in both groups was statistically less than that before operation(P＜0.01),and the JOA score in both groups was statistically more than that before opera-tion(P＜0.01),and there were no significant differences in VAS score and JOA score between groups,respec-tively(P＞0.05).Conclusions:The optimized design scheme of 3D-printed DGT is helpful in improving the ac-curacy and safety of subaxial CPS insertion.

Ten-Year Results of Reconstruction for Rheumatoid Cervical Spine Lesions and Occurrence Factor of Subaxial Subluxation

STUDY DESIGN: Retrospective chart review. PURPOSE: This study evaluated long-term surgical outcomes of computer-assisted reconstruction using transarticular or cervical pedicle screws for cervical spine lesions caused by advanced rheumatoid arthritis (RA). OVERVIEW OF LITERATURE: We routinely employ C1–C2 transarticular and cervical pedicle screw instrumentation to reconstruct advanced and unstable RA cervical lesions. However, few reports are available on the long-term results of surgical reconstruction for rheumatoid cervical disorders, particularly regarding cervical pedicle screw fixation. METHODS: Six subjects (all female) with RA cervical lesions who underwent atlantoaxial or occipitocervical fixation and were followed for at least 10 years were retrospectively studied. A frameless, stereotactic, optoelectronic, computed tomography-based image guidance system was used for correct screw placement. Variables including the Japanese Orthopaedic Association score, EuroQol, Ranawat value, and C2–C7 angle before and 2, 5, and 10 years after surgery were assessed along with the occurrence of subaxial subluxation (SAS). RESULTS: Mean age at initial surgery was 58.2±7 years (range, 51–68 years), and mean follow-up period was 141±11 months (range, 122–153 months). Lesions included atlantoaxial subluxation (AAS, n=2) and AAS+vertical subluxation (n=4). Mean C2–C7 lordotic angle before and 2, 5, and 10 years after surgery was 20.1°±6.1°, 21.0°±4.0°, 18.8°±4.7°, and 17.8°±5.3°, respectively. SAS did not occur in cases maintaining the C2–C7 lordotic angle. In two cases where the C2–C7 lordotic angle declined from 5 years postoperatively, SAS occurred at the C2–C3 level in one and at the C4–C5 level in the other, both of which required reoperation. CONCLUSIONS: Patients with rheumatoid cervical lesions who undergo atlantoaxial or occipitocervical fixation using C1–C2 transarticular or pedicle screws carry a risk of SAS for up to 10 years postoperatively, which may require reoperation.

Evidence-based guideline for the management of acute subaxial cervical spine injury / 中华外科杂志

In order to provide the clinical guidelines of acute subaxial cervical spine injury for the Chinese orthopedic surgeons, the Spine Trauma Group of Chinese Association of Orthopedic Surgeons compiled this guidelines.The guidelines apply to adult patients with acute (less than 3 weeks) subaxial cervical spine and/(or) spinal cord or nerve root injuries. The Study Group wrote the guidelines by setting up questions, determining search words, screening literatures according to inclusion and exclusion criteria, analyzing the included literatures, confirming evidence levels and then providing recommendations. The guidelines include 141 literatures, 27 Chinese articles and 114 English articles. The guidelines set up 18 questions divided into 4 sections: pre-hospital care, diagnosis and evaluation, treatment and prevention of complications, which include 39 recommendations.

Evidence-based guideline for the management of acute subaxial cervical spine injury / 中华外科杂志

In order to provide the clinical guidelines of acute subaxial cervical spine injury for the Chinese orthopedic surgeons, the Spine Trauma Group of Chinese Association of Orthopedic Surgeons compiled this guidelines.The guidelines apply to adult patients with acute (less than 3 weeks) subaxial cervical spine and/(or) spinal cord or nerve root injuries. The Study Group wrote the guidelines by setting up questions, determining search words, screening literatures according to inclusion and exclusion criteria, analyzing the included literatures, confirming evidence levels and then providing recommendations. The guidelines include 141 literatures, 27 Chinese articles and 114 English articles. The guidelines set up 18 questions divided into 4 sections: pre-hospital care, diagnosis and evaluation, treatment and prevention of complications, which include 39 recommendations.

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>

Osteoradionecrosis in Subaxial Cervical Spine - a Rare and Devastating Complication: A Case Report

Osteoradionecrosis, a rare complication of radiation therapy, is a slow progression disease which affects the surrounding structures of spinal components. It essentially weakens the soft tissue and bony configuration and can cause nerve impingement or cord compression. We describe a patient who underwent radiotherapy for thyroid cancer and presented with cervical kyphosis with anterolisthesis of C3/C4 and C4/C5 some 32 years later. We explore the role of anterior and posterior fusion, as well as hyperbaric oxygen therapy in promoting healing.

Polyetheretherketone Cage with Demineralized Bone Matrix Can Replace Iliac Crest Autografts for Anterior Cervical Discectomy and Fusion in Subaxial Cervical Spine Injuries

OBJECTIVE: This study aimed to compare the clinical and radiologic outcomes of patients with subaxial cervical injury who underwent anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft or polyetheretherketone (PEEK) cages using demineralized bone matrix (DBM). METHODS: From January 2005 to December 2010, 70 patients who underwent one-level ACDF with plate fixation for post-traumatic subaxial cervical spinal injury in a single institution were retrospectively investigated. Autologous iliac crest grafts were used in 33 patients (Group I), whereas 37 patients underwent ACDF using a PEEK cage filled with DBM (Group II). Plain radiographs were used to assess bone fusion, interbody height (IBH), segmental angle (SA), overall cervical sagittal alignment (CSA, C2–7 angle), and development of adjacent segmental degeneration (ASD). Clinical outcome was assessed using a visual analog scale (VAS) for pain and Frankel grade. RESULTS: The mean follow-up duration for patients in Group I and Group II was 28.9 and 25.4 months, respectively. All patients from both groups achieved solid fusion during the follow-up period. The IBH and SA of the fused segment and CSA in Group II were better maintained during the follow-up period. Nine patients in Group I and two patients in Group II developed radiologic ASD. There were no statistically significant differences in the VAS score and Frankel grade between the groups. CONCLUSION: This study showed that PEEK cage filled with DBM, and plate fixation is at least as safe and effective as ACDF using autograft, with good maintenance of cervical alignment. With advantages such as no donor site morbidity and no graft-related complications, PEEK cage filled with DBM, and plate fixation provide a promising surgical option for treating traumatic subaxial cervical spine injuries.

A Novel Patient-Specific Drill Guide Template for Pedicle Screw Insertion into the Subaxial Cervical Spine Utilizing Stereolithographic Modelling: An In Vitro Study

STUDY DESIGN: Cadaveric study. PURPOSE: The purpose of this study was to assess the accuracy and feasibility of cervical pedicle screw (CPS) insertion into the subaxial cervical spine placed using a patient-specific drill guide template constructed from a stereolithographic model. OVERVIEW OF LITERATURE: CPS fixation is an invaluable tool for posterior cervical fixation because of its biomechanical advantages. The major drawback is its narrow corridor that allows very little clearance for neural and vascular injuries. METHODS: Fifty subaxial pedicles of the cervical vertebrae from five cadavers were scanned into thin slices using computed tomography (CT). Digital imaging and communications in medicine images of the cadaver spine were digitally processed and printed to scale as a three-dimensional (3D) model. Drill guide templates were manually moulded over the 3D-printed models incorporating pins inserted in the pedicles. The drill guide templates were used for precise placement of the drill holes in the pedicles of cadaveric specimens for pedicle screw fixation. RESULTS: The instrumented cadaveric spines were subjected to CT to assess the accuracy of our pedicle placement by an external observer. Our patient-specific drill guide template had an accuracy of 94%. CONCLUSIONS: The use of a patient-specific drill guide constructed using stereolithography improved the accuracy of CPS placement in a cadaveric model.

Application of guide combined with probing the internal wall of pedicle screw trajectory for subaxial cervical pedicle screw placement / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the skill and evaluate the accuracy for application of guide combined with probing the internal wall of pedicle screw trajectory for subaxial cervical pedicle screw placement.</p><p><b>METHODS</b>Subaxial cervical pedicle screw was inserted in 11 patients by the guide combined with probing the internal wall of pedicle screw trajectory from January 2014 to October 2016, including 7 males and 4 females with an average age of 48.1 years(ranged 32 to 63 years). There were 4 cases with cervical spondylotic myelopathy, 4 with fracture and dislocation of cervical vertebrae, 1 with cervical cord injury without fracture and dislocation, and 2 with atlantoaxialfracture and dislocation. The target pedicle's diameter, optimal entry point, sagittal angle and cross-sectional angle were measured by CT before operation. During operation, the pedicle screw inserted angle was controlled by a guide with a self-designed protractor and probed the internal wall of pedicle screw trajectory as medial safety margin of insertion screw. The accuracy of cervical pedicle screw was evaluated by CT with classification of four grades and assessed whether there was injury of spine cord or vertebral artery postoperatively.</p><p><b>RESULTS</b>Seventy-one cervical pedicle screws were placed among 11 patients, and no one had been found with clinical manifestations of injury of spine cord (or nerve root) or vertebral artery after operation. According to postoperative CT scan for evaluating the grade of screw position, 52 screws were in grade 0, 13 in grade 1, 4 in grade 2, 2 in grade 3, and 91% (65/71) located in good position. In total, 6 screws were incorreted in placement, and 4 cases of them broke medial wall and 2 cases broke lateral wall.</p><p><b>CONCLUSIONS</b>The method of probing the internal wall of pedicle screw trajectory for subaxial cervical pedicle screw placement is safe and reliable, but the studying curve is long. Probing the internal wall of pedicle screw trajectory and controlling the insertion angle by guide with a protractor are key points of this technology.</p>

Evaluation of the SLICS use in the treatment of subaxial cervical spine injuries / Avaliação do SLICS no tratamento das lesões da coluna cervical sub-axial

The SLICS (Sub-axial Cervical Spine Injury Classification System) was proposed to help in the decision-making of sub-axial cervical spine trauma (SCST), even though the literature assessing its safety and efficacy is scarce. Method We compared a cohort series of patients surgically treated based on surgeon’s preference with patients treated based on the SLICS. Results From 2009-10, 12 patients were included. The SLICS score ranged from 2 to 9 points (mean of 5.5). Two patients had the SLICS < 4 points. From 2011-13, 28 patients were included. The SLICS score ranged from 4 to 9 points (mean of 6). There was no neurological deterioration in any group. Conclusion After using the SLICS there was a decrease in the number of patients with less severe injuries that were treated surgically. This suggests that the SLICS can be helpful in differentiating mild from severe injuries, potentially improving the results of treatment. .

O SLICS (Sub-axial Cervical Spine Injury Classification System) foi proposto para auxílio na tomada de decisão no tratamento do traumatismo da coluna cervical sub-axial. Contudo, existem poucos trabalhos que avaliem sua segurança e eficácia. Método Realizamos estudo comparativo de série histórica de pacientes operados baseados na indicação pessoal do cirurgião com pacientes tratados baseados na aplicação do SLICS. Resultados Entre 2009-10, 12 pacientes foram incluídos. O SLICS escore variou de 2 a 9 pontos (média de 5,5) com dois pacientes com escore menor que 4. Entre 2011-13, 28 pacientes foram incluídos. O escore de SLICS variou de 4 a 9 pontos, com média de 6. Conclusão Observamos que após o uso do SLICS houve uma diminuição do número de pacientes operados com lesões mais estáveis. Isso sugere que o SLICS pode ser útil para auxiliar a diferenciação de lesões leves das graves, eventualmente melhorando os resultados do tratamento. .

Bilateral Pedicle and Crossed Translaminar Screws in C2

Multiple techniques exist for the fixation of C2, including axial pedicle screws and bilateral translaminar screws. We describe a novel method of incorporating both the translaminar and pedicle screws within C2 to improve fixation to the subaxial spine in patients requiring posterior cervical instrumentation for deformity correction or instability. We report three cases of patients with cervical spinal instability, who underwent cervical spine instrumentation for stabilization and/or deformity correction. Bilateral C2 pedicle screws were inserted, followed by bilateral crossed laminar screws. The instrumentation method successfully achieved fixation in all three patients. There were no immediate postoperative complications, and hardware positioning was satisfactory. Instrumenting C2 with translaminar and pedicle screws is technically feasible, and it may improve fixation to the subaxial spine in patients with poor bone quality or severe subaxial deformity, which require a stronger instrumentation construct.

High Grade Infective Spondylolisthesis of Cervical Spine Secondary to Tuberculosis

Spondylolisthesis coexisting with tuberculosis is rarely reported. There is a controversy whether spondylolisthesis coexists or precedes tuberculosis. Few cases of pathological spondylolisthesis secondary to tuberculous spondylodiscitis have been reported in the lumbar and lumbosacral spine. All cases in the literature presented as anterolisthesis, except one which presented as posterolisthesis of lumbar spine. Spondylolisthesis in the cervical spine is mainly degenerative and traumatic. Spondylolisthesis due to tuberculosis is not reported in the lower cervical spine. The exact mechanism of such an occurrence of spondylolisthesis with tuberculosis is sparsely reported in the literature and inadequately understood. We report a rare case of high grade pathological posterolisthesis of the lower cervical spine due to tubercular spondylodiscitis in a 67-year-old woman managed surgically with a three-year follow-up period. This case highlights the varied and complex presentation of tuberculosis of the lower cervical spine and gives insight into its pathogenesis, diagnosis, and management.

The Secondary Contiguous or Non-contiguous Subchondral Bone Impactions in Subaxial Cervical Spinal Injury: Incidence and Associated Primary Injury Patterns

PURPOSE: To evaluate the incidence of secondary contiguous or non-contiguous subchondral bone impactions (SBI) in subaxial cervical spinal injury and associated primary injury patterns. MATERIALS AND METHODS: A retrospective review of computed tomography, magnetic resonance imaging, and medical records was carried out for 47 patients who had sustained a subaxial cervical spinal injury. Presence, number, level, and sites of secondary contiguous or non-contiguous SBI were recorded. To evaluate primary injury patterns, the level and number of primary injury sites of subaxial cervical spine injury, injury morphology, anterior/posterior discoligamentous complex (ADC/PDC) injury, posterior ligamentous complex (PLC) injury, spinal cord injury, and mechanism of injury (MOI) were analyzed. Differences in primary injury pattern of subaxial cervical spine injury and MOI between patients with and without SBI, and between contiguous or non-contiguous SBI were analyzed using the Mann-Whitney U test, Pearson's chi square test and Fisher's exact test. RESULTS: Eighteen patients (18/47, 38.29%) had developed contiguous (n=9) or non-contiguous (n=9) SBI, most commonly involving T3 (15/47, 31.91%) and 3 levels (6/18, 33.33%). All SBIs had developed near the anterosuperior region of the body and the superior endplate and were the result of a high-impact MOI. SBIs were statistically significant in association with injury morphology and PLC injury (P=0.001, P=0.009, respectively) at the primary injury site. Non-contiguous SBI was more frequently accompanied by upper cervical spinal injuries in association with PDC injuries, as opposed to contiguous SBI, with statistical significance (P=0.009), while no other statistically significant differences were found. CONCLUSION: Secondary SBIs are common and probably associated with subaxial cervical spinal injuries with high energy compressive flexion forces.

Alterações radiográficas de coluna cervical em artrite reumatoide / Radiographic changes of cervical spine in rheumatoid arthritis

INTRODUÇÃO: O envolvimento da coluna cervical é comum na artrite reumatoide (AR). OBJETIVO: Estudar a prevalência das alterações radiológicas de coluna cervical em pacientes com AR e sua associação com perfil clinico e sorológico da doença. MÉTODOS: Analisaram-se as radiografias de coluna cervical em perfil neutro hiperextensão, hiperflexão e transoral de 80 pacientes com AR para presença de subluxação atlanto-axial (LAA), invaginação basilar (IB) e instabilidade subaxial (ISA). Dados de perfil demográfico, clínico (nódulos, pneumonite intersticial, síndrome Sjögren secundária, uso de medicamentos etc.) e sorológico (FR, anti-CCP e FAN) foram obtidos por revisão de prontuários. RESULTADOS: Havia alguma alteração de eixo de coluna cervical em 26/80 (32,5%); em 12/80 (15%) havia LAA; em 6/80(7,5%) existia IB; em 13/80 (16,2%) existia ISA. Erosões em odontoide foram vistas 16/80 (20,0%). As alterações do eixo cervical estavam associadas com idade de início da doença e duração da mesma (P = 0,03 e 0,02, respectivamente). Não se encontrou associação das alterações em coluna cervical com raça, gênero, nódulos, pneumonite intersticial, Sjögren secundário, FR, FAN ou anti-CCP. Pacientes com alterações do eixo cervical apresentavam mais erosões de odontoide (P = 0,03). CONCLUSÕES: Alterações radiológicas em eixo de coluna cervical são comuns e aparecem mais frequentemente em indivíduos com diagnóstico mais precoce de AR e maior tempo de doença.

INTRODUCTION: The involvement of the cervical spine is a common feature of rheumatoid arthritis (RA). OBJECTIVE: To study the prevalence of radiographic changes of the cervical spine in patients with RA and their association with clinical and serological profiles of the disease. METHODS: We analysed lateral (neutral position, hyperextension, hyperflexion) and transoral views of cervical spine radiographs from 80 individuals with RA to investigate the presence of atlanto-axial subluxation (AAS), basilar invagination (BI), and subaxial instability (SAI). Demographic, clinical (nodules, interstitial pneumonitis, secondary Sjögren's syndrome, medications etc.), and serologic (rheumatoid factor - RF, cyclic citrullinated peptide antibody - anti-CCP, and antinuclear factor - ANF) data were obtained from the clinical records. RESULTS: Cervical spine misalignments were identified in 26/80 (32.5%) participants; AAS occurred in 12/80 (15%) participants, BI in 6/80 (7.5%), and SAI in 13/80 (32.5%). Odontoid erosions were identified in 16/80 (20.0%) participants. Cervical spine misalignment exhibited associations with age at onset and disease duration (P = 0.03 and 0.02, respectively). No associations were identified between the cervical spine changes and the participants' ethnicity or gender, presence of nodules, interstitial pneumonitis, secondary Sjögren's syndrome, RF, ANF, or anti-CCP. The participants with cervical spine misalignment exhibited higher frequencies of odontoid erosion (P = 0.03). CONCLUSIONS: Cervical spine misalignment was a common radiographic finding and occurred more frequently in participants with earlier onset and longer length of RA.

Accuracy and Safety in Pedicle Screw Placement in the Thoracic and Lumbar Spines : Comparison Study between Conventional C-Arm Fluoroscopy and Navigation Coupled with O-Arm(R) Guided Methods

OBJECTIVE: The authors performed a retrospective study to assess the accuracy and clinical benefits of a navigation coupled with O-arm(R) system guided method in the thoracic and lumbar spines by comparing with a C-arm fluoroscopy-guided method. METHODS: Under the navigation guidance, 106 pedicle screws inserted from T7 to S1 in 24 patients, and using the fluoroscopy guidance, 204 pedicle screws from T5 to S1 in 45 patients. The position of screws within the pedicle was classified into four groups, from grade 0 (no violation cortex) to 3 (more than 4 mm violation). The location of violated pedicle cortex was also assessed. Intra-operative parameters including time required for preparation of screwing procedure, times for screwing and the number of X-ray shot were assessed in each group. RESULTS: Grade 0 was observed in 186 (91.2%) screws of the fluoroscopy-guided group, and 99 (93.4%) of the navigation-guided group. Mean time required for inserting a screw was 3.8 minutes in the fluoroscopy-guided group, and 4.5 minutes in the navigation-guided group. Mean time required for preparation of screw placement was 4 minutes in the fluoroscopy-guided group, and 19 minutes in the navigation-guided group. The fluoroscopy-guided group required mean 8.9 times of X-ray shot for each screw placement. CONCLUSION: The screw placement under the navigation-guidance coupled with O-arm(R) system appears to be more accurate and safer than that under the fluoroscopy guidance, although the preparation and screwing time for the navigation-guided surgery is longer than that for the fluoroscopy-guided surgery.

Interobserver and Intraobserver Reliability of Sub-Axial Injury Classification and Severity Scale between Radiologist, Resident and Spine Surgeon

OBJECTIVE: The sub-axial injury classification (SLIC) and severity scale was developed to decide whether to operate the cervical injured patient or not, but the reliability of SLIC and severity scale among the different physicians was not well known. Therefore, we evaluated the reliability of SLIC among a spine surgeon, a resident of neurosurgery and a neuro-radiologist. METHODS: In retrograde review in single hospital from 2002 to 2009 years, 75 cases of sub-axial spine injured patients underwent operation. Each case was blindly reviewed for the SLIC and severity scale by 3 different observers by two times with 4 weeks interval with randomly allocated. The compared axis was the injury morphology score, the disco-ligamentous complex score, the neurological status score and total SLIC score; the neurological status score was derived from the review of medical record. The kappa value was used for the statistical analysis. RESULTS: Interobserver agreement of SLIC and severity scale was substantial agreement in the score of injury morphology [intraclass correlation (ICC)=0.603] and total SLIC and severity sacle (ICC value=0.775), but was fair agreement in the disco-ligamentous complex score (ICC value=0.304). Intraobserver agreements were almost perfect agreement in whole scales with ICC of 0.974 in a spine surgeon, 0.948 in a resident of neurosurgery, and 0.963 in a neuro-radiologist. CONCLUSION: The SLIC and severity scale is comprehensive and easily applicable tool in spine injured patient. Moreover, it is very useful tool to communicate among spine surgeons, residents of neurosurgery and neuro-radiologists with sufficient reproducibility.

Radiographic Analysis of Atlantoaxial Fusion for Atlantoaxial Instability: Comparison of Posterior wiring, Transarticular screw, Posterior screw-rod fixation

STUDY DESIGN: This is a retrospective study. OBJECTIVES: We wanted to clarify the association between the position of the atlantoaxial fusion angle and the change of the subaxial cervical spine alignment (SCA) and the reduction loss after atlantoaxial fusion (AAF) using the posterior wiring technique (PWT), transarticular screw fixation (TAF) and posterior screw-rod fixation (PSR) for treating atlantoaxial instability (AAI). SUMMARY OF LITERATURE REVIEW: There are not many studies on the change of the SCA and the reduction loss after AAF. MATERIALS AND METHODS: Thirty five patients underwent AAF for AAI from 1986 to 2008. The mean follow-up period was 59.5 months. The surgical techniques were divided into three groups, that is, PWT: 17 patients, TAS: 10 and PSR: 8. The causes of instability were transverse ligament rupture in 12 patients, rheumatoid arthritis in 11, Os odontoideum in 6 and nonunion of an odontoid fracture in 6. Plain radiographs were used to assess the atlanto-dental interval, the posterior arch-lamina angle, the change of the SCA and the time of fusion. RESULTS: Fusion was achieved in all the patients within 3.5 months (range: 3-5 months). The radiologic findings in the 5 PWT patients showed a reduction loss and 3 patients showed subaxial cervical kyphosis (SCK). The TAS group had no reduction loss or SCK. The PSR group had no reduction loss and one patient showed SCK. A statistically significant reduction loss and SCK occurred in the group in which there was a posterior arch-laminar angle greater than 10 degrees before and after surgery. CONCLUSIONS: For the treatment of AAI, the position of the AAF is associated with the change of the postoperative SCA. The preoperative lodortic position of C1-2 should be maintained to prevent the change of the SCA.

Therapeutic options to treate subaxial cervical fracture-dislocation with locked-facet / 中国矫形外科杂志

[Objective]To evaluate a simple,safty and effective therapeutic option to treate subaxial cervical fracture-dislocation with locked-facet.[Method]With the patients being awake and supervized under X-ray fluoroscopy,the authors used the early and continued closed skull traction-reduction to treate 16 cases of traumatic subaxial cervical fracture-dislocation with locked-facet.Before the beginning of the treatment,all the patients were taken for X-ray plain films and MRI/CT examinations as well as American Spinal Injury Association(ASIA) neurological function grade.The dynamic ASIA neurological function scale and X-ray fluoroscopy examnations were asked during the skull traction–reduction procedures.The average interval from the traumatic events to begin to skull traction–reduction was 31 hours(6-52 hours).The authors would continue the skull traction to maintain the anatomy position as soon as they succeeded in reducing the dislocation with locked-facet,forthmore they would take the anterior operation or combinations with anterior and posterior operations during the best condition.[Result]The MRI scans showed that there were 8 disc hernations and 5 disc disruptions at the dislocation levels before traction–reduction procedures.The ASIA scale were 7 grade C,5 grade D and 4 grade E,respectively.All the 16 cases succeeded in reduction as well as no neurological deterioration occurred.The postreduction MRI scans showed that 2 disc herations had converted to nearly normal disc position and another 4 disc hernations remained unchanged.Accordingly,2 disc disruption remained unchanged and another case had converted to disc hernation.The average traction weight was 19 kg(10~32 kg) and average traction time was 53 minutes(30~135 minutes).[Conclusion]Under the intensive dynamic ASIA neurological function grade and X-Ray fluoroscopy examnations,with the patients being awake and co-operation,the early and continued closed skull traction-reduction and then performing elective anterior or anterior-posterior surgery depending on the patient's overall and local status to treate subaxial cervical fracture-dislocation with locked-facet is safe and effective.

Transarticular screws versus Magerl lateral mass screws:an anatomic comparison of their possible effects on injury to spinal nerve roots / 中华创伤骨科杂志

Objective To compare anatomically the potential incidences of injury to the nerve roots of ventral and dorsal rami caused by the transarticular screws and Magerl lateral mass screws in the fixation of subaxial cervical spine.Methods Fixations with the transarticular screws and Magerl lateral mass screws were performed in this study.For each kind of fixation,20 screws were inserted from C3 to C7 in two specimens.A 20-ram long screw was used to over-penetrate the ventral cortex.The anterolateral aspect of the cervical spine was carefully dissected to allow ob- servation of the screw-ramus relationship.Results The overall percentage of nerve violation was significantly lower in the transarticular screw fixation(45%)than in the Magerl lateral mass screw fixation(90%).The difference was sta- tistically significant between the two fixation methods(P＜0.05).The greatest percentages of nerve violation caused by the transarticular screws and lateral mass screws were found at the dorsal ramus,25% and 45%,respectively. Conclusion The potential risk of nerve root violation caused by the transarticular screw technique is lower than that by the Magerl lateral mass screw technique in the lower cervical spine.

Analysis of Posterior Cervical Fixation and Fusion in Subaxial Cervical Spine Injury

OBJECTIVE: In the retrospective analyzing 19 consecutive patients with subaxial cervical spine(C3~T1) injury treated by posterior cervical fixation and fusion, clinical manifestation, radiologic finding, operative technique, and postoperative results following 6 months were analyzed. MATERIALS AND METHODS: Most common fracture level was C4-5, mean age 41, and male to female ratio 13: 6. The most common cause of injury was motor vehicle accident(17 cases). In 19 cervical procedures, interspinous triple wiring was done in 14 cases, lateral mass plating in 5 cases, and additional anterior fusion in 2 cases. RESULTS: Twelve weeks after operation, all cases were reviewed by plain cervical radiogram. In 17 cases that treated by posterior fusion only, 14 cases(81%) had kyphotic angle change less than 5degrees, 2 cases(12%) 5-20degrees, and 1 case(6%) more than 20degrees. Overall fusion rate was 88%, and there was no significant difference of bone fusion rate between autogenous bone graft and allogenous bone graft. CONCLUSION: In the case of severe posterior column injury or displacement, posterior approach seems superior to anterior approach, but in the case of combined anterior column injury, anterior approach is considered necessary. In this study, posterior fixation and fusion might be acceptable procedure for subaxial cervical fracture and dislocation, owing to its high fusion rate, low kyphotic angulation and low operation related complication rate.