Morphometric study and anatomical variation with its incidence of foramina transversaria on the lower cervical vertebrae / Estudio morfométrico y variación anatómica con la incidencia de forámenes transversos en las vértebras cervicales inferiores

SUMMARY: Anatomical variation of the foramina transversaria (FT) is associated with vertebral neurovascular symptoms and can cause complications after lower spine surgery, especially cervical pedicle screw (CPS) insertion. FT variation has been documented and classified in various populations, as this information can help increase cervical stability in subaxial vertebral surgery. Although the morphometry of the upper cervical spine in Thai populations has been reported, there have yet been no studies examining the features of FT. The FT of dried cervical spines (C3-C7; left and right side; n = 107, male = 53 and female = 54) were examined for morphological variation, and their anteroposterior (AP) and transverse (T) diameters were measured using a digital vernier caliper. Morphometric data and variations were compared by sex and lateral side. It was that the C3-C6 FT in both sexes were round, and the C7 FT was elliptical with an oblique right side. FT diameters did not differ significantly by sex except for the AP diameters of C6-C7 and for T diameters of C4 and C7. The left AP diameters of C3-C6 were significantly longer than the right, as were the T diameters of C4 and C7 FT. Additionally, T diameter was significantly longer than that of the AP, except that of the left C6 in male spines, which did not differ from the AP. Most FT examined were round. These findings should be considered in the provisional diagnosis of vertebral neurovascular symptoms caused by FT variation as well as that of neurovascular damage after cervical pedicle screw placement.

La variación anatómica del foramen transverso (FT) se asocia con síntomas neurovasculares vertebrales y puede causar complicaciones después de la cirugía de columna cervical inferior, especialmente la inserción de tornillos pediculares cervicales (TPC). La variación del FT se ha documentado y clasificado en varias poblaciones, ya que esta información puede ayudar a aumentar la estabilidad cervical en la cirugía vertebral subaxial. Aunque se ha informado sobre la morfometría de la columna cervical superior en poblaciones tailandesas, aún no se han realizado estudios que examinen las características de FT. Se examinó la variación morfológica del FT de vértebras cervicales secas (C3-C7; lado izquierdo y derecho; n = 107, hombres = 53 y mujeres = 54), y se midieron sus diámetros anteroposterior (AP) y transverso (T) usando un pie de metro digital. Se compararon datos morfométricos y variaciones por sexo y lado. Los FT de C3-a C6 en ambos sexos eran redondos, y el FT C7 era elíptico con el lado derecho oblicuo. Los diámetros del FT no difirieron significativamente por sexo excepto para los diámetros AP de C6- C7 y para los diámetros transversos de C4 y C7. Los diámetros AP izquierdos de C3-C6 eran significativamente más largos que los del lado derecho, al igual que los diámetros transversos de C4 y C7. Además, el diámetro transverso fue significativamente mayor que el AP, excepto el C6 izquierdo en las vértebras de hombres, que no difirió del AP. La mayoría de los FT examinados eran redondos. Estos hallazgos deben ser considerados en el diagnóstico provisional de síntomas neurovasculares vertebrales causados por la variación del FT, así como en el de daño neurovascular tras la colocación de tornillos pediculares cervicales.

Biomechanical Comparison of Internal Fixation by Traditional and Cortical Bone Trajectory Pedicle Screw / 医用生物力学

Objective To compare the effects of cortical bone trajectory ( CBT) and traditional trajectory ( TT)pedicle screw internal fixation on the range of motion (ROM) and rod system stress of normal and osteoporotic(OP) spines. Methods The L3-S1 finite element models of normal and OP spines were established. The screwrod system with two kinds of trajectory was used for internal fixation of the L4-5 segment, so as to simulate sixphysiological loads, namely, flexion, extension, left / right bending, left / right rotation. The effects of two internalfixation methods on ROMs and maximum equivalent stress of screws in normal and OP spines were compared.Results For both bone conditions, CBT and TT significantly reduced ROM of the fixed segment (L4-5) and theentire segment of lower lumbar spine ( L3-S1). However, the ROM decline of CBT group was slightly smaller than that of TT group, and their ROMs were similar under flexion and extension, but the ROM differences were significant under lateral bending and axial rotation. In addition, for both the normal and OP spine models, themaximum equivalent stress of screws in CBT group was significantly higher than that in TT group. Compared withTT group, the screw stress of CBT group in normal spine model under flexion and extension, lateral bending,axial rotation was increased by 27% , 268% and 58% , respectively. However, when CBT technique was used atthe same time, the OP spine model had a smaller screw stress distribution than the normal spine model.Conclusions Compared with TT technique, CBT technique can achieve higher screw stress under OP conditionand reduce screw stress concentration under normal bone condition. In addition, CBT slightly increases ROMs of each segment, which is conducive to recovery of spinal physiological function after surgery. Lateral bending and axial rotation can produce negative mechanical effects, and these two physiological loads should be avoided.

Percutaneous pedicle screw fixation combined expandable tubular retractor in the treatment of spinal metastases / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effectiveness of percutaneous pedicle screw fixation combined expandable tubular retractor in the treatment of patients with spinal metastases.@*METHODS@#In the study, 12 patients of spinal metastases treated with percutaneous pedicle screw fixation combined expandable tubular retractor in our hospital were retrospectively reviewed between June 2017 and October 2019. Among the 12 patients, 9 were males and 3 were females; the median age was 62.5 years [(65.1±2.9) years]. The decompression segment of 7 patients was located at the lower thoracic spine (including 1 patient with incomplete paraplegia) and the decompression segment of 5 patients was located at the lumbar spine; Tomita score was 6.0±0.6. Perioperative data of the patients were reviewed. Visual analog scale (VAS score), Karnofsky score, and Eastern Cooperative Oncology Group (ECOG) score were compared before and after surgery. The patient's survival, adjuvant treatment, and internal fixation failure were observed in the follow-up period.@*RESULTS@#All the 12 patients had a successful operation with percuta-neous pedicle screw fixation combined expandable tubular retractor. The average operative time, blood loss, and blood transfused of the patients were (247.0±14.6) min, (804.2±222.3) mL and (500.0±100.0) mL, respectively. The average amount of drainage was (240.8±79.3) mL. Drainage tubes were pulled out early postoperative [(3.2±0.3) d], allowing early mobilization. The patients discharged (7.8±0.8) d postoperative. All the patients were followed up for 6-30 months, and the average overall survival time was (13.6±2.4) months. During the follow-up period, 2 patients experienced screw displacement, the internal fixation was stable after conservative treatment and no revision surgery was performed. The VAS of the patients was 7.1±0.2 before surgery, which decreased to 2.3±0.1 and 2.8±0.4 at 3 and 6 months after surgery (P < 0.05). The Karnofsky score of the patients was 59.2±1.9 before surgery, which increased to 75.0±1.9 and 74.2±3.1 at 3 and 6 months after surgery (P < 0.05). The ECOG of the patients was 2.3±0.2 before surgery, which decreased to 1.7±0.1 and 1.7±0.2 at 3 and 6 months after surgery (P < 0.05).@*CONCLUSION@#For selected patients with spinal metastases, minimally invasive surgical treatment of spinal metastases (percutaneous pedicle screw internal fixation combined with expandable tubular retractor) can effectively relieve the clinical symptoms and improve the quality of life, with satisfactory clinical outcome.

Treatment of spinal burst fractures with pedicle screw fixation at high altitude area / 中国骨伤

OBJECTIVE@#According to the characteristics of spinal burst fractures in high-altitude areas and the local medical conditions, to explore the clinical efficacy of short-segment fixation with pedicle screws combined with screw placement in injured vertebrae in the treatment of thoracolumbar burst fractures.@*METHODS@#From August 2018 to December 2021, 12 patients with single-vertebral thoracolumbar burst fractures without neurological symptoms were treated with injured vertebral screw placement technique, including 7 males and 5 females;aged 29 to 54 years old, with an average of(42.50±7.95) years old;6 cases of traffic accident injury, 4 cases of high fall injury, 2 cases of heavy object injury;2 cases of T11, 4 cases of T12, 3 cases of L1, 2 cases of L2, and 1 case of L3. In the operation, screws were first placed in the upper and lower vertebrae of the fracture, pedicle screws were placed in the injured vertebra, and connecting rods were installed, and the fractured vertebral body was reset by positioning and distraction. Visual analogue scale (VAS) and Japanese Orthopedic Association (JOA) scoring were used to evaluate the changes in pain and quality of life of patients, and the kyphotic correction rate and correction loss rate of the injured segment were measured by X-ray.@*RESULTS@#All operations were successful without significant intraoperative complications. All 12 patients were followed up, the duration ranged from 9 to 27 months, with an mean of (17.75±5.79) months. VAS at 3 days after operation was significantly higher than that at admission (t=6.701, P=0.000). There was significant difference in JOA score between 9 months after operation and at admission (t=5.085, P=0.000). Three days after operation, Cobb angle was (4.42±1.16)°, and the correction rate was (82±5)% compared with (25.67±5.71)° at admission. Cobb angle was (5.08±1.24) °at 9 months after operation, with a corrected loss rate of (16±13)%. No loosening or breakage of internal fixation was found.@*CONCLUSION@#Under the high-altitude hypobaric and hypoxic environment, the effect of the operation should be ensured while reducing the trauma. The application of the technique of placing screws on the injured vertebra can effectively restore and maintain the height of the injured vertebra, with less bleeding and shorter fixed segments, which is an effective method.

O-arm real-time guidance in cervical pedicle screw fixation / 中国骨伤

OBJECTIVE@#To explore the technical aspects of the accuracy of cervical pedicle screw placement with O-arm guidance.@*METHODS@#The clinical data of 21 patients who underwent cervical pedicle screw fixation by O-arm real-time guidance from December 2015 to January 2020 were analyzed retrospectively. There were 15 males and 6 females, aged from 29 to 76 years old with an average of (45.3±11.5) years. The postoperative CT scan was utilized to evaluate the placement of the pedicle screw and classified according to the Gertzbein and Robbins classification.@*RESULTS@#A total of 132 pedicle screws were implanted in 21 patients, 116 at C3-C6 and 16 at C1 and C2. According to Gertzbein & Robbins classification, the overall breach rates were found to be 11.36% (15/132) with 73.33% (11 screws) Grade B, 26.67% (4 screws) Grade C, and no Grade D or E screw breaches. There were no pedicle screw placement related complications at final follow-up.@*CONCLUSION@#The application of O-arm real-time guidance technology can make cervical pedicle screw placement reliable. High accuracy and better intra-operative control can increase surgeon's confidence in using cervical pedicle instrumentation. Considering the high-risk nature of anatomical area around cervical pedicle and the possibility of catastrophic complications, the spine surgeon should have sufficient surgical skills, experience, ensures stringent verification of the system, and never relies solely on the navigation system.

Comparison of efficacy of O-arm assisted and free-hand pedicle screw placement in the treatment of AO type C thoracolumbar fracture / 中华创伤杂志

Objective:To compare the effect of O-arm assisted and free-hand pedicle screw placement in the treatment of AO type C thoracolumbar fracture.Methods:A retrospective cohort study was used to analyze the clinical data of 34 patients with type C thoracolumbar fracture admitted to Henan Provincial People′s Hospital from January 2018 to June 2021, including 23 males and 11 females; aged 42-63 years [(50.4±7.4)years]. The fracture was located at T 11 in 4 patients, T 12 in 10, L 1 in 12, L 2 in 6, T 11~12/L 1 in 1 and T 12/L 1 in 1. Posterior reduction and internal fixation was carried out for all patients, of whom 18 were treated with O-arm assisted pedicle screw placement (navigation group) and 16 with free-hand pedicle screw placement (free-hand group). The operation time, single screw placement time, intraoperative bleeding volume, operation mode and screw placement accuracy were compared between the two groups. The kyphotic Cobb angle, visual analogue score (VAS) and American Spinal Injury Association (ASIA) score were compared between the two groups before operation, at 1 week after operation, at 3 months after operation and at the last follow-up. Postoperative complications were observed. Results:All patients were followed up for 12-29 months [(16.8±6.1)months]. There was no significant difference between the two groups in the operation time, intraoperative bleeding volume and operation mode (all P>0.05). The single screw placement time was (9.4±1.6)minutes in navigation group, but was (10.8±1.5)minutes in free-hand group ( P<0.05). The screw placement accuracy was 97.4% in navigation group, but was 81.5% in free-hand group ( P<0.01). The kyphotic Cobb angle and VAS had no significant differences between the two groups before operation (all P>0.05). The kyphotic Cobb angle in navigation group and free-hand group was (4.3±1.1)° and (5.9±1.1)° at 1 week after operation, (4.4±1.2)° and (5.7±1.3)° at 3 months after operation, and (4.4±1.2)° and (6.8±0.9)° at the last follow-up, decreased significantly from that before operation [(21.8±3.1)°, (22.2±3.2)°] (all P<0.01). The kyphotic Cobb angle in navigation group was significantly lower than that in free-hand group at 1 week, 3 months after operation and at the last follow-up (all P<0.01). The VAS in navigation group and free-hand group was (3.2±0.7)points and (4.1±0.7)points at 1 week after operation, (2.4±0.6)points and (3.0±0.8)points at 3 months after operation, and (1.8±0.9)points and (2.6±0.7)points at the last follow-up, decreased significantly from that before operation [(8.4±0.8)points, (8.3±0.9)points] (all P<0.01). The VAS in navigation group was significantly lower than that in free-hand group at 1 week, 3 months after operation and at the last follow-up (all P<0.01). The ASIA score showed no significant difference within and between the two groups before operation, at 1 week, 3 months after operation and at the last follow-up (all P>0.05). Postoperative incision infection occurred in 1 patient in both groups ( P>0.05). Implant failure such as loosening or displacement was not observed in navigation group, and only occurred in 2 patients in free-hand group ( P>0.05). Conclusion:Compared with free-hand pedicle screw placement, O-arm assisted pedicle screw placement in the treatment of AO type C thoracolumbar fracture has advantages of rapid and accurate screw placement, good reduction and notable pain relief.

Morphometric Assessment of Pedicles of Indian Adult Lumbar Vertebrae: A Cross Sectional Study

Introduction: Lumbar vertebral column is exposed to various kinds of stress during locomotion. In erect posture weight transmitted through posterior part including pedicles. This causes deformities of this region as the age advances in many individuals. Proper correction of deformity is challenging. There have been advances in spinal fusion procedures and interspinous implantation of devices including pedicle screws. Use of unsuitable dimensions of screw may cause problem of destruction of pedicle. Correct metricular data of pedicle is necessary for choice of appropriate screw size. Aims and Objectives: 1) To measure the various dimensions in Indian adult human lumbar vertebral pedicles. 2) To prepare data of lumbar pedicles useful in various surgical procedures. Material and Methods: A Cross-sectional study was done on 45 dry, fully ossified human lumbar vertebral sets. The bones were grouped into typical (L1 to L4) and atypical (L5) lumbar vertebrae. The dimensions measured included pedicle length, height, thickness, axial length, transverse and sagittal angles. ‘Digital Vernier Caliper’ and Protractor were used. The data was analyzed statistically. Results: The mean length, height and thickness of typical vertebral pedicles increases gradually. In atypical (L5), pedicle thickness suddenly increases. The transverse angle of pedicle elevated gradually from L1 to L4 but at L5, it abruptly increased. Conclusions: The study reported significant differences in several dimensions of pedicles of typical as well as atypical lumbar vertebrae. These differences should be considered by neurosurgeons.

The Influence of Thread Tap Mismatch on Pedicle Screw Pullout Strength / A influência da incompatibilidade do macho de rosca na resistência à extração do parafuso pedicular

Abstract Objective We aimed to study the "in vitro" pullout strength of SpineGuard/Zavation Dynamic Surgical Guidance Z-Direct Screw (DSG Screw, SpineGuard Inc, Boulder, Colorado, USA), a screw designed to be inserted using a direct insertion technique. Methods Dynamic Surgical Guidance Screws of 5.5 and 6.5 mm were introduced into polyurethane blocks with a density of 10 PCF (0,16g/cm3). According to the experimental group, screws were inserted without pilot hole, with pilot without tapping, undertapping and line-to-line tapping. Screw pullout tests were performed using a universal test machine after screw insertion into polyurethane blocks. Results Screws inserted directly into the polyurethane blocks without pilot hole and tapping showed a statistically higher pullout strength. Insertion of the screw without tapping or with undertapping increases the pullout screw strength compared with lineto-line tapping. Conclusion Dynamic Surgical Guidance Screw showed the highest pullout strength after its insertion without pilot hole and tapping.

Resumo Objetivo Nosso objetivo foi estudar a resistência à extração "in vitro" do parafuso SpineGuard/Zavation Dynamic Surgical Guidance Z-Direct (Parafuso DSG Guia Cirúrgico Dinâmico, SpineGuard Inc, Boulder, Colorado, USA), um parafuso projetado para ser inserido utilizando a técnica de inserção direta. Métodos Os parafusos DSG de 5,5 e 6,5 mm foram introduzidos em blocos de poliuretano com densidade de 10 PCF (0,16g/cm3). De acordo com o grupo experimental, os parafusos foram inseridos sem um orifício piloto, com um orifício piloto sem o macheamento, com macheamento e com macheamento linha a linha. Os testes de extração do parafuso foram realizados em uma máquina de teste universal, após a inserção do parafuso em blocos de poliuretano. Resultados Os parafusos inseridos diretamente nos blocos de poliuretano sem o orifício piloto e o macheamento mostraram uma resistência à extração estatisticamente maior. A inserção do parafuso sem o macheamento ou com o macho de menor diâmetro aumenta a resistência à extração do parafuso em comparação com o macheamento linha a linha. Conclusão O parafuso DSG apresentou a maior resistência à extração após a inserção sem o orifício piloto e o macheamento.

Suspension exercise training can improve walking and balance after thoracolumbar fracture and spinal cord injury / 中华物理医学与康复杂志

Objective:To explore the effect of suspension exercise training (SET) on the lumbar function and balance ability of patients with thoracolumbar fracture and spinal cord injury.Methods:Totally 64 patients with thoracolumbar fracture and spinalcord injury were randomly divided into a control group and an observation group, each of 32. Both groups received pedicle screw reduction with internal fixation and spinal dome decompression, followed by routine post-operative rehabilitation. In addition, the observation group performed double bridge and single leg suspension training and pelvic lift training. Everyone′s walking ability, spinal nerve functionality and balance were evaluated 3 days after the operation and 2 months after the training. Stride frequency, stride length and walking speed were observed. American Spinal Injury Association (ASIA) nerve function classifications were assigned. The trajectory length, trajectory included area and movement deviation of each subject′s center of gravity (CG) was recorded.Results:The average stride frequency, step length and walking speed of the observation group had all improved significantly after the intervention, and were significantly better than the control group′s averages at that point. This was also true of the proportion in ASIA neurological function grade D (65.63%), CG trajectory length and area, and the Romberg rate of deviation along the X-axis and Y-axis of the CG.Conclusion:SET training after pedicle screw reduction and internal fixation and spinal dome decompression can significantly improve the spinal nerve functioning of persons after a thoracolumbar fracture with incomplete spinal cord injury. It enhances their balance and walking ability. Such therapy is worthy of clinical promotion and application.

Analysis on influencing factors of vertebral body height reloss after pedicle screw fixation of thoracolumbar fracture / 中华创伤杂志

Objective:To investigate the related factors of vertebral body height reloss after pedicle screw fixation of thoracolumbar fracture and to determe the optimum prediction point.Methods:A retrospective case control study was made on 215 patients with thoracolumbar fracture admitted to Second Affiliated Hospital of Soochow University from January 2010 to December 2017. There were 155 males and 60 females，aged 21-80 years［（48.6±10.4）years］. According to Denis fracture classification，there were 73 patients with compression fractures（type A in 15 patients，type B in 51，type C in 7），135 burst fractures（type A in 28 patients，type B in 87，type C in 20）and flexion distraction fractures（type A in 4，type B in 2，type C in 1）. All patients were treated by pedicle screw fixation. Follow-up lasted for 12- 48 months［（23.8±8.2）months］. Vertebral body height loss occurred in 86 patients（loss group），but did not in 129 patients（non-loss group）. The two groups were compared concerning sex，age，osteoporosis self-assessment tool for Asians（OSTA），body mass index（BMI），fracture types，number of fractured vertebrae，preoperative sagittal Cobb angle，preoperative degree of vertebral compression，number of screws placed in injured vertebrae，extent of vertebral reset and other related factors. Univariate analysis was used to identify the correlation of those factors with vertebral body height reloss. Multivariate Logistic regression analysis was performed to identify the independent factors for the height reloss with the receiver operating characteristic curve（ROC）and area under the curve（AUC）calculated to evaluate the optimum point in prediction of vertebral height reloss.Results:The two groups showed no significant differences in sex，age，BMI，fracture types，number of injured vertebrae，preoperative sagittal Cobb angle and number of screws placed in injured vertebrae（ P>0.05），but the differences were statistically significant in OSTA，preoperative degree of vertebral compression and extent of vertebral reset（ P<0.05）. According to the univariate analysis，OSTA，preoperative degree of vertebral compression and extent of vertebral reset were significantly correlated with the occurrence of vertebral body height reloss（ P<0.05）. According to the multivariate Logistic regression，OSTA（ OR=1.109，95% CI 0.527-0.685， P<0.05）and preoperative degree of vertebral compression（ OR =0.038，95% CI 0.539-0.689， P<0.05）were significantly related to vertebral body height reloss. The AUC relating OSTA and preoperative degree of vertebral compression to vertebral body height reloss was 0.604 and 0.614，respectively. The optimum prediction point of OSTA and preoperative degree of vertebral compression for vertebral body height reloss was 1.9 and 31.3%，respectively. Conclusions:OSTA and the preoperative degree of vertebral compression are independent risk factors for vertebral body height reloss. OSTA≤1.9 or preoperative degree of vertebral compression ≥31.3% indicates a significantly higher risk of postoperative vertebral body height reloss.

Efficacy of posterior pedicle screw reduction and internal fixation of atlantoaxial fractures: comparison between O-arm navigation assisted and free-hand techniques / 中华创伤杂志

Objective:To investigate the effect of O-arm navigation assisted posterior pedicle screw reduction and internal fixation of atlantoaxial fractures.Methods:A retrospective case-control study was conducted to analyze 37 patients with atlantoaxial fractures admitted to Third Hospital of Hebei Medical University from January 2016 to June 2018, including 22 males and 15 females, aged from 29 to 68 years [(50.9±9.8)years]. The posterior pedicle screw reduction and internal fixation was performed under O-arm navigation system (navigation group, n=24), and using free-hand technique (free-hand group, n=13). The operation time and blood loss were compared between the two groups. The Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) were used to evaluate the clinical efficacy before operation, 7 days operation and at the last follow-up. The complications were detected. A total of 86 screws were placed in navigation group (Neo grade 0: 83 screws, grade 1: 2 screws, grade 2: 1 screw ), and 44 screws were inserted in free-hand group (Neo grade 0: 36 screws, grade 1: 5 screws, grade 2: 2 screws, grade 3: 1 screw)( P<0.05). Classification of screw positions proposed by Neo et al was used to evaluate the position relationship between the screw and the bone cortex and the incidence of screw penetration. Results:All patients were followed up 24-38 months [(27.7±4.0)months]. The operation time in navigation group was (189.8±35.4)minutes, significantly shorter than (221.5±48.6)minutes in free-hand group ( P<0.05). The bleeding volume in navigation group was 300.0 (250.0, 537.5)ml , significantly less than 500.0 (425.0, 625.0)ml in free-hand group ( P<0.05). Both groups showed significantly enhanced JOA and decreased NDI after operation and at last follow-up, compared with those before operation ( P<0.05). However, there was no significant difference in JOA and NDI between the two groups ( P>0.05). No severe complications such as neurovascular injury occurred during operation. The incidence of cortical penetration was 3% (3/86) in navigation group and 18% (8/44) in free-hand group ( P<0.05). Conclusions:In the process of posterior atlantoaxial pedicle screw placement, the application of O-arm navigation can significantly reduce the operation time and amount of bleeding, and enhance the accuracy of pedicle screw implantation.

Effect of modified Wiltse approach pedicle screw internal fixation combined with transpedicular bone grafting on the vertebral body and complications of senile osteoporotic vertebral compression fractures / 中华内分泌外科杂志

Objective:To investigate the effects of internal fixation with pedicle screw via modified Wiltse approach combined with transpedicular bone grafting on the vertebral body and complications of senile osteoporotic vertebral compression fractures (OVCF) .Methods:Ninety-four elderly patients with osteoporotic vertebral compression fractures who were admitted to Hangzhou Fuyang Traditional Chinese Medicine Orthopedics Hospital from Oct. 2018 to Oct. 2019 were selected as the research objects. The patients were divided into control group and observation group according to the random ball touch method. For 47 cases, the control group underwent posterior short-segment reduction and internal fixation combined with transpedicular bone grafting, and the observation group underwent modified Wiltse approach pedicle internal fixation combined with transpedicular bone grafting. The two groups were observed and compared in terms of surgery related indicators, the condition of the injured vertebrae, the recovery of the vertebral body, the length of hospitalization and fracture healing time, and the incidence of complications.Results:In comparison of the operation-related indexes between the two groups, the intraoperative blood loss, 3d postoperative visual analogue scale (VAS) score and operation time of the observation group were significantly lower, than those of the control group ( P<0.05) . In comparison of the condition of the injured vertebrae between the two groups, there was no significant difference in the ratio of the loss rate of the injured vertebrae Cobb angle, vertebral body sagittal plane index, and vertebral body height between the two groups before operation ( P>0.05) . The loss rates of Cobb angle and vertebral body height of the injured vertebrae in the two groups were lower than that before operation at 3 days after operation, and the sagittal index of the vertebral body was higher than before operation at 1 year after operation ( P<0.05) . The loss rate of Cobb angle and vertebral body height of the injured vertebral body in the observation group was significantly lower than that of the control group at 3 days postoperatively, and the vertebral body sagittal plane index was significantly higher than that of the control group at 1 year postoperatively ( P<0.05) . Comparing the recovery of injured vertebrae between the two groups, there was no statistically significant difference between the preoperative oswestry disability index (ODI) scores of the two groups ( P>0.05) , the improvement rate of Cobb angle and the recovery rate of vertebral body height in the observation group, ODI scores at 3 months after operation were significantly higher than those of the control group ( P<0.05) . The hospitalization time and fracture healing time of the observation group were significantly lower than those of the control group ( P<0.05) . The total incidence of complications in the observation group (4.26%) was significantly lower than the total incidence of complications in the control group (19.15%) ( P<0.05) . Conclusion:The combined use of internal fixation with pedicle screw via modified Wiltse approach combined with transpedicular bone grafting in treatment of elderly OVCF can reduce the amount of intraoperative blood loss, shorten the operation time and hospital stay and fracture healing time, improve the Cobb angle of the injured vertebra, promote the recovery of the height and function of the injured vertebra, and reduce the incidence of complications.

Bone cement pedicle screw fixation and fusion in the treatment of degenerative spinal disease with osteoporosis: One-year follow-up / 中国组织工程研究

BACKGROUND: Even pedicle screw fixation system is commonly used in spinal surgery, elderly patients with high bone fragility lack of bone elasticity, insufficient holding power of pedicle screw. Thus, there is a risk of loosening and pulling out the screws, leading to failure of spine reduction and fixation. Thus, we need to explore new method to increase the stability of the pedicle screw system. OBJECTIVE: To explore the long-term effect of pedicle screw internal fixation with bone cement in the treatment of different types of lumbar degenerative diseases with osteoporosis. METHODS: Sixty patients suffering from degenerative spinal disease with the complication of osteoporosis were randomly assigned to control group and trial group (n=30 per group). Before adopting the treatment of bone cement pedicle screw fixation and fusion, all patients had taken pre-operation examination, X-ray, CT and MRI scan. The patients in the control group were treated with conventional pedicle screw technology, and those in the experimental group were treated with bone cement on the basis of the conventional pedicle screw technology. Visual analogue scale score and Oswestry disability index were compared between the two groups 1 day before surgery, 1 week, 6 months, and 1 year after surgery. Complications were observed after surgery to evaluate the effect of the operation. RESULTS AND CONCLUSION: (1) At 1 week, 6 months and 1 year after surgery, the visual analogue scale score and Oswestry disability index were significantly better than those of pre-operation (P < 0.05). Visual analogue scale score and Oswestry disability index were significantly lower at 6 months and 1 year after surgery than those 1 week after surgery (P < 0.05). Visual analogue scale score and Oswestry disability index were significantly lower at 1 year than those at 6 months after surgery (P < 0.05). (2) Visual analogue scale score and Oswestry disability index were better in the trial group than those in the control group at 6 months and 1 year after surgery (P < 0.05). (3) The incidence of internal fixation rod loosening was lower in the trial group than that in the control group. (4) It is concluded that bone cement pedicle screw fixation and fusion in the treatment of degenerative spinal disease with osteoporosis can effectively improve the clinical symptoms and reduce the occurrence of complications. It is safe and effective in clinical application, and the long-term treatment effect is acceptable.

Biomechanical Study of Novel Articular Process Fixation System Combined with Unilateral Pedicle Screw Fixation / 医用生物力学

Objective To study the stability of lumbar spine after transforaminal lumbar interbody fusion (TLIF) surgery combined with a novel articular process fixation system (APFS). Methods Based on the validated finite element model of L3-S1 intact segment (Model A), TLIF surgery was simulated to establish bilateral pedicle screw TLIF model (Model B), right unilateral pedicle screw TLIF model (Model C), APFS combined with right pedicle screw fixation TLIF model (Model D). The range of motion (ROM) of the lumbar spine model and stress distributions on pedicle screws, APFS and interbody fusion cages under different working conditions were observed. Results The overall ROMs of Models B, C, and D under different working conditions were comparable, which were all smaller than those of the physiological model. Compared with Models B and C, the maximum compressive stress of the right pedicle screw and the interbody fusion cage in Model D was the smallest or between Models B and C under different working conditions. Model D had the largest peak stress of APFS and right pedicle screw during anterior flexion. Conclusions APFS combined with contralateral pedicle screw fixation can be used as a novel fixation method for TLIF surgery of lumbar spine.

Effect of Wiltse approach pedicle screw-laminar hook internal fixation combined with autologous ilium transplantation for repairing single-segment lumbar spondylolysis / 解放军医学杂志

[Abstract] Objective To analyze the characteristics of lumbar spondylolysis in military patients, and explore the clinical effect of Wiltse approach pedicle screw-laminar hook internal fixation combined with autologous ilium transplantation in repairing single-segment lumbar spondylolysis. Methods Thirty-three military patients with single-segment lumbar spondylolysis were admitted to the 940 Hospital of Joint Service Support Force of Chinese PLA from January 2016 to January 2019. The Wiltse approach pedicle screw-lamina hook internal fixation combined with autogenous ilium transplantation was performed to repair the lumber spondylolysis, the patients were then followed up to evaluate the visual analogue scale (VAS) and Oswestry dysfunction index (ODI) of lumbar pain, and compared with that before surgery. 3-D CT of lumbar spine was used to evaluate the bone graft fusion in the isthmus. Results The army patients accounted for 63.6% (21/33) of all the cases. The injured segments were located at L4 and L5 segment, with the L5 segment (84.8%, 28/33) being the most common. The operation time was 85-150 min, the intraoperative blood loss was 50-150 ml, postoperative drainage volume was 10-30 ml. VAS score of lower back pain decreased from 5.8±0.7 before surgery to 1.4±0.8 three months after surgery, and to 0.4±0.5 at the last follow-up, the difference was statistically significant (P<0.05). ODI decreased from 41.2%±5.8% before surgery to 12%±3.9% 3 months after surgery, and to 9.5%±2.6% at the last follow-up, the difference was statistically significant (P<0.05). At 3 months, 6 months and 12 months follow-up, the bone graft fusion rate was 18.2% (6/33), 48.5% (16/33) and 84.8% (28/33), respectively, and the average bone graft fusion time was 7.0±2.8 months. Conclusion Wiltse approach pedicle screw-laminar hook internal fixation combined with autogenous ilium transplantation is a feasible and effective minimally invasive solution for repairing single-segment lumbar spondylolysis of military patients with shorter bone graft fusion time.

Accuracy of robot-assisted and fluoroscopy-guided pedicle screw placement: A meta-analysis / 中国组织工程研究

BACKGROUND: Traditional fluoroscopy-guided pedicle screw fixation is not highly accurate and can lead to serious surgical complications. To reduce surgical complications and improve the success rate of surgery, robotic assistive technology emerges as the times require. OBJECTIVE: To compare the difference of robot-assisted and fluoroscopy-guided pedicle screw placement using meta-analysis. METHODS: The study included clinical controlled trials on robot-assisted and fluoroscopy-guided pedicle screw placement published in and outside China from December 2008 to December 2018. The retrieval was performed in the online databases include Embase, PubMed, Central, CNKI, CQVIP, Wanfang, and CBM. Keywords used for search were robot assisted, fluoroscopy guided, conventional, freehand, pedicle screw in English and Chinese. After the data were extracted, statistical software Review Manager 5.3 was used for data-analysis. RESULTS AND CONCLUSION: (1) Based on the above search strategy, 1 615 studies were retrieved, and 13 were included. (2) Statistical analysis found that placement accuracy in the robot-assisted group was better than that of the fluoroscopy group [95%CI(1.55, 4.06), P=0.000 2]. Radiation intensity in the fluoroscopy group was lower than that in the robot-assisted group [95%CI(0.42, 0.82), P < 0.001], and the difference was statistically significant. (3) However, the incidence of complications [95%CI(0.23, 4.65), P=0.96] and revised surgery [95%CI(0.03, 3.17), P=0.33] were not statistically significant between the robot-assisted group and the fluoroscopy group. Intraoperative fluoroscopy time was similar between the two groups [95%CI(-38.55, 78.26), P=0.51]. Postoperative back pain [95%CI(-0.58, 0.38), P=0.68], leg pain score [95%CI(-0.20, 0.19), P=0.94] and operation time [95%CI(-6.33, 53.02), P=0.12] were also similar between the two groups, and the differences were not statistically significant. (4) Compared with fluoroscopy, robot-assisted technique has higher pedicle screw placement accuracy, especially under percutaneous conditions. Inevitably, the intraoperative radiation intensity is also more than conventional fluoroscopy.

Comparison of the short-segment and long-segment cement-augmented pedicle screw fixation for osteoporotic thoracolumbar fracture: A finite element study / 中国组织工程研究

BACKGROUND: Pedicle screw fixation combined with cement-augmented is an effective method for the treatment of severe osteoporotic vertebral fractures, but there is no uniform standard. The range of fixed segments is one of the focus of clinical controversy. OBJECTIVE: To establish a three-dimensional finite element model of the short-segment and long-segment cement-augmented pedicle screw fixation for osteoporotic thoracolumbar fracture, and to analyze the biomechanical characteristics of adjacent segment structures, fractured vertebral bodies and internal fixation devices. METHODS: The T 9 -L 5 segment of a volunteer without obvious degenerative disease was selected for CT scan. The CT images of Dicom format were obtained, and the engineering software was imported to establish a finite element geometric model to simulate the thoracolumbar fracture and the short-segment and long-segment cement-augmented pedicle screw fixation models. The relevant material parameters were set and the biomechanical characteristics of the two groups were compared and analyzed. RESULTS AND CONCLUSION: (1) The stress on the vertebrae was mainly concentrated on the periphery of the vertebral body and the small facet of the attachment. In the four directions flexion, extension, left-sided and right-sided curvature, the maximum stress of the proximal and distal adjacent vertebrae in the long-segment group was greater than that in the short-segment group. The stress of the intervertebral disc was mainly concentrated in the peripheral annulus. The maximum stress of the proximal and distal adjacent intervertebral discs was greater in the short -segment than in the long-segment, but the high stress area of the long-segment was larger than that of the short-segment. Therefore, long-segment fixation might accelerate the degeneration of adjacent segments.(2) The vertebral bodies of the long-segment group and the short-segment group were displaced to different extents, and the displacements in the left and right directions were the most obvious. In the six movement directions, the displacement and maximum stress of the injured segment of the short-segment group were greater than those of the long-segment group. So the long-segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short- segment group.and the displacements in the left and right directions were the most obvious. In the six movement directions, the displacement and maximum stress of the injured segment of the short-segment group were greater than those of the long-segment group. So the long- segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group.and the displacements in the left and right directions were the most obvious. In the six movement directions, the displacement and maximum stress of the injured segment of the short-segment group were greater than those of the long-segment group. So the long- segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group.So the long-segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group. So the long-segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group.

Comparison of biomechanical characteristics of lumbar spine after unilateral and bilateral internal fixation / 中国组织工程研究

BACKGROUND: Pedicle screw fixation is the preferred surgical treatment for clinical treatment of lumbar degenerative disease currently. The stability of pedicle screw fixation system can be evaluated from the perspective of biomechanics and finite element method is more and more popular in analyzing stress of pedicle screw fixation of vertebral body for researchers. OBJECTIVE: To analyze the stress and displacement changes of human lumbar spine in bending movement from the biomechanical point of view when unilateral and bilateral pedicle screws are fixed, providing theoretical reference for practical clinical application. METHODS: Three-dimensional models were established based on CT data of the volunteers. The volunteers signed the informed consent. This study was approved by the Hospital Ethics Committee. Abaqus software was used to simulate the actual stress conditions. Finite element analysis of lumbar spine flexion was performed during unilateral and bilateral pedicle screw fixation. The stress and displacement of lumbar vertebra, disc and pedicle screw were observed under two fixation methods. RESULTS AND CONCLUSION: (1) Under bilateral fixation, the stress on the left screw was 22.2 MPa, and the stress on the right screw was 21.14 MPa, which was far less than the stress of the screw under unilateral fixation (79.19 MPa). The stress of intervertebral disc in unilateral fixation was 87% larger than that in bilateral fixation; the stress of vertebral body in bilateral fixation was 72% smaller than that in unilateral fixation. (2) From the perspective of displacement, the displacement of screw, lumbar disc and centrum under bilateral fixation were 53%, 55% and 62% smaller than that under unilateral fixation, respectively. (3) Therefore, from the mechanical point of view, bilateral pedicle screw fixation has less stress level, which is friendlier to the human body than unilateral fixation and thus more conducive to the recovery of patients.

Computer navigation-assisted surgical treatment with osteotomy for upper thoracic kyphosis / 中国组织工程研究

BACKGROUND: The biomechanical characteristics of kyphosis of the upper thoracic vertebra are unique. Decompression and internal fixation are relatively difficult. Previous relevant studies and case reports are few, and there is a lack of research on correction of kyphosis of the upper thoracic section with the assistance of computer navigation. OBJECTIVE: To explore the clinical effect of computer navigation-assisted surgical treatment of upper thoracic kyphosis by screws and osteotomy. METHODS: Totally 18 patients with kyphotic deformity of the spine (T1-T4) were admitted in Beijing Jishuitan Hospital from June 2011 to June 2018, including 11 males and 7 females, aged 12 to 59 years. They were all treated with computer-assisted surgical treatment with PSO osteotomy. Local Cobb angle of the upper thoracic kyphosis was determined during final follow-up. Cervical visual analogue scale, Nurick grades, EMS scores and satisfaction of the surgery were evaluated. This study was approved by the Ethics Committee of Beijing Jishuitan Hospital (approval No. 201709-23). RESULTS AND CONCLUSION: (1) A total of 18 patients were followed up for 6-90 months at an average time of (33. 73±35. 33) months. (2) The local Cobb angle of 18 patients at the last follow-up was significantly improved [(47. 32±9. 92)°, (24. 01 ±7. 64)°, P < 0. 001]. Cervical visual analogue scale score at the last follow-up was significantly lower than that before surgery (3. 64±2. 16, 0. 73±1. 01, P< 0. 001). Nurick score at the last follow-up was significantly lower than that before surgery (2. 91 ±0. 94, 0. 82±1. 47, P < 0. 001). EMS score at the last follow-up was significantly higher than that before surgery (14. 45±0. 93), 17. 09±1. 45, P< 0. 001). (3) Surgical satisfaction was excellent (n=16) or good (n=2). (4) At the last follow-up, 18 patients had no adverse reactions related to implants, and the wound healed well without screw loosening. (5) The results showed that reasonable osteotomy correction with computer-assisted surgery and PSO osteotomy could effectively treat kyphosis of upper thoracic segment.

Early- and mid-term effects of trans-injured and cross-injured vertebra pedicle screw fixation in the treatment of thoracolumbar fractures / 中国组织工程研究

BACKGROUND: The bone trabecula of the vertebral body cannot be fully recovered, and the mechanical stability of the sagittal position of the spinal column Is affected. The antl-bendlng force and the anti-torsion force of the short-segment fixation of fractured vertebra are obviously Increased. The bearing load of various activities such as flexion, extension, and rotation of the vertebral body is increased. The stability of the injured vertebra is better maintained, and favorable conditions are created for fracture healing. OBJECTIVE: To compare the early- and mid-term follow-up results of trans-injured and cross-injured vertebra pedicle screw fixation in the treatment of thoracolumbar fractures. METHODS: Eighty-eight patients with thoracolumbar vertebrae fracture treated in Affiliated Hospital of Qinghai University from April 2017 to April 2018 were divided into trans-injured vertebra group and cross-injured vertebra group according to the treatment plan. All patients signed the informed consent. This study was approved by the Hospital Ethics Committee. Intraoperative blood loss, operation time, postoperative bed rest time, postoperative site infection, and subcutaneous hematoma were analyzed in both groups. Visual analogue scale score, Oswestry Disability Index, anterior edge height ratio and kyphosis Cobb angle were compared before surgery, 6 and 12 months after surgery between the two groups. RESULTS AND CONCLUSION: (1) The operation time was longer and intraoperative blood loss was higher in the trans-injured group than those in the cross-injured group, but the postoperative bed rest time was shorter in the trans-injured group than that in the cross-injured group (P 0.05). (3) At 6 and 12 months after surgery, visual analogue scale score and Oswestry Disability Index were lower in the trans-injured group than in the cross-injured group; anterior edge height ratio was larger in the trans-injured group than in the cross-injured group; kyphosis Cobb angle was smaller in the trans-injured group than in the cross-injured group (all P < 0.05). (4) Incidence of complications was higher in the cross-injured group (30%) than in the trans-injured group (7%) (P=0.001). (5) The treatment of thoracolumbar fracture with trans-injured pedicle screw can not only effectively restore and maintain the injured vertebral height and kyphosis Cobb angle, restore the physiological height and curvature of vertebral body, but also the incidence of postoperative complications is low, which can effectively improve the prognosis of patients and improve the quality of life of patients.