Objective To ascertain whether augmentation pedicle screw fixation with polymethylmethacrylate (PMMA) can enhance the stability of unstable thoracolumbar burst fractures of osteoporotic spine. Methods Six fresh frozen female osteoporotic spines (T10-L5) were harvested and an anterior and posterior columnunstable model of L1 was made. Each specimen was fixated with plate and the stability test were performed by flexion, extension, axial rotation and lateral bending. The test of fatigue was done with MTS 858.The tests were repeated after screws were augmented with PMMA. To compare the biomechanical stability of 6 different conditions:○anormal specimens(control), ○bdefectmodel fixed with plate, not augmented and not fatigued, ○cafter fatigued, not augmented, ○dscrews augmented with PMMA, not fatigued, ○e after augmented and fatigued. ResultsIn ○b,○d and ○e conditions, the ranges of motion(ROM) were 6.23±1.56，4.49±1.00，4.46±1.83 inflexion and 6.60±1.80，4.41±0.82，4.46±1.83 in extension. There was no significant difference (Pgt;0.05), they were significantly smaller than those in ○a and ○c conditions (8.75±1.88，1.47±2.25 and 8.92±2.97，12.24±3.08) (Plt;0.01).Conclusion The results demonstrated that augmentation pedicle screws fixation with PMMA can increase the stability of osteoporotic spine.
Objective To develop a high-accuracy, better-safety and low-cost cervical pedicle locator system for guiding cervical pedicle screw placement. Methods Cervical pedicle screw locator system was made of stainless steel. Ten cervical specimens from voluntary donation were divided into two groups according to compatibil ity design: control group inwhich 60 screws were planted into C2-7 by free hand; and experimental group in which 60 screws were planted into C2-7 under the guidance of three-dimensional locator system. The condition of screw insertion was observed and the accuracy was evaluated by the integrity of pedicle walls. Results In the control group, 32 screws (53.33%) were placed inside the pedicles and 28 (46.67%) were outside; 9 screws (15.00%) led to nerve root injury, 5 screws (8.33%) caused vertebral artery injury and no spinal cord injury occurred; and the qual ification ratio of screw insertion was 76.67% (excellent 32, fair 14, poor 14). While in the experimental group, 54 screws (90.00%) were placed inside the pedicles and 6 (10.00%) were outside; 1 screw (1.67%) caused vertebral artery injury and no nerve root injury and spinal cord injury occurred; and the qual ification ratio of screw insertion was 98.33% (excellent 54, fair 5, poor 1). There was significant difference between the two groups (P lt; 0.05). Conclusion Cervical pedicle screw locator system has the advantages of easy manipulation, high accuracy of screw placement and low cost. With further study, it can be appl ied to the cl inical.
To investigate the shortsegment pedicle screw in treating degenerative L4 spondylolisthesis and the relationship of the preliminarily bending degree of the titanium rod with the lumbar lordosisangle, the slipping angle and the slipping percentage and to evaluate the clinical coincidence and curative effects of the preliminarilybent rod. MethodsFrom September 2005 to March 2007, 31 female patients (age, 40-70 years; average, 58.3 years) were admitted for surgical treatment of their L4 degenerative spondylolisthesis (MeyerdingⅠ°, Ⅱ°)． Their lumbar lordosis angle （x1）, slipping angle (x2), and slipping percentage (x3) were measured in the L4,5 segment before operation. During the operation, the titanium rod bent beforehand according to the corresponding standards was inserted. The angle of the bent rod (Y) was measured, and then the multiple linear regression equation was established. The regression equation was applied to the surgical treatment of the 30 patients.Results According to the criteria in the JOA scoring system, the 31 patients had scores of 8.300± 1.080 and 26.916±1.859 before operation and after operation, respectively. There was a significant difference between before operation and after operation（Plt;0.05）. The established multiple linear regression equation was as follows:Y=0.1390-0.327logx1+0.463x2+0.288x32．The operating time was 51.290±3.408 min in the 30 patients who underwent an insertion of the preliminarilybent rod during the operation; however, the operating time was 102.360±5.004 min in the 31 patients who underwent an insertion of the bent rod that was made based on experience during the previous operations. There was a significant difference in the operating time between the two kinds of the rods （Plt;0.05）. Estimated according to 90%, 95% and 99% of the areas under the normalcurve, the clinical coincidence rates in the preliminarily bending degrees of the titanium rod in the 30 patients were 80.00％，90.00％ and 96.67％, respectively.Conclusion The titanium rod that has been bent into a certain angle before operation according to the established criteria can definitely diminish its strain during operation and efficiently shorten the operating time．Thiskind of the titanium rod has a good coincidence in clinical application and can be effectively used in clinical practice.It is worth reference during the clinical operation.
Objective To explore the clinical effect of PSIS-A robot-assisted percutaneous screw in the treatment of thoracolumbar fracture. Methods Patients with thoracolumbar fracture who were hospitalized in Mianyang Orthopedic Hospital between August 2022 and January 2024 and required percutaneous pedicle screw f ixation were selected. Patients were divided into robot group and free hand group by random number table. Operative time, intraoperative bleeding, intraoperative radiation dose and time, implant accuracy rate, small joint invasion rate, Visual Analogue Scale score for pain and other indexes were compared between the two groups. Results A total of 60 patients were included. Among them, there were 28 cases in the robot group and 32 cases in the free hand group. On the third day after surgery, the Visual Analogue Scale score of the robot group was better than that of the free hand group (P=0.003). Except for intraoperative bleeding and radiation frequency (P>0.05), the surgical time, average nail implantation time, and intraoperative radiation dose in the robot group were all lower than those in the free hand group (P<0.05). The accuracy and excellence rate of nail planting in the robot group were higher than those in the free hand group (94.6% vs. 84.9%; χ2=7.806, P=0.005). There was no statistically significant difference in the acceptable accuracy rate (96.4% vs. 91.1%; χ2=3.240, P=0.072) and the incidence of screw facet joint invasion (7.2% vs.14.1%; χ2=3.608, P=0.058) between the two groups. Conclusion The application of PSIS-A type robot assisted percutaneous minimally invasive pedicle screw fixation in the treatment of thoracolumbar fr actures is promising.
Objective To compare the effectiveness of unilateral biportal endoscopy (UBE) technique assisted spinal canal decompression combined with percutaneous pedicle screw internal fixation versus traditional open decompression and internal fixation for treatment of lumbar burst fractures. MethodsA retrospective study was conducted on the clinical data of 61 patients with single-segment lumbar burst fractures who met the selection criteria and were admitted between October 2022 and December 2023. Of them, 25 patients received UBE technique assisted decompression combined with percutaneous pedicle screw fixation (UBE group), while 36 patients were treated with traditional posterior unilateral hemilaminectomy decompression and internal fixation (open group). There was no significant difference in baseline data between the two groups (P>0.05), including gender, age, body mass index, fracture segment, cause of injury, AO classification of lumbar fractures, and preoperative height ratio of the anterior margin of injured vertebra, segmental kyphosis angle, rate of spinal canal invasion, the classification of American Spinal Injury Association (ASIA) grading, visual analogue scale (VAS) score, and Oswestry disability index (ODI). The operation time, intraoperative blood loss, and postoperative complications were recorded and compared between the two groups. VAS score, ODI, and ASIA grading were used to evaluate the effectiveness before operation, at 1 week after operation, and at last follow-up. Lumbar anteroposterior and lateral X-ray films and CT were performed to measure the segmental kyphosis angle, height ratio of the anterior margin of injured vertebra, and the rate of spinal canal invasion.ResultsSurgery was successfully completed in both groups. No complication such as dural sac, nerve root, or vascular injury was found during operation, and all incisions healed by first intention. There was no significant difference in operation time between the two groups (P>0.05), the UBE group revealed significant less intraoperative blood loss when compared with open group (P<0.05). Patients in both groups were followed up 6-20 months, with an average of 13 months. There was no loosening, breakage, or failure of internal fixation in all patients. The ASIA grading, VAS score, ODI of the two groups significantly improved at 1 week after operation and further improved at last follow-up (P<0.05). There was no significant difference in ASIA grading at 1 week after operation and last follow-up between the two groups (P>0.05), but the VAS score and ODI in the UBE group were significantly superior to the open group (P<0.05). At 1 week after operation, the height ratio of the anterior margin of injured vertebra, segmental kyphosis angle, rate of spinal canal invasion significantly improved when compared to preoperative ones (P<0.05), the height ratio of the anterior margin of injured vertebra and segmental kyphosis angle significantly decreased at last follow-up when compared to the values at 1 week after operation (P<0.05), but the rate of spinal canal invasion was further significantly improved, and there was no significant difference between the two groups at different time point postoperatively. ConclusionUBE technique assisted spinal canal decompression combined with percutaneous pedicle screw fixation is a safe and effective treatment for lumbar burst fractures, which with little trauma and faster recovery when compared with traditional open decompression and internal fixation.
Objective To review the research background, biomechanical characteristics, and clinical application of fenestrated pedicle screw (FPS). Methods The recent literature about the study and application of FPS was reviewed, analyzed, and summarized. Results Compared with the technique of conventional pedicle screw augmentation, FPS can be augmented with polymethyl methacrylate (PMMA) through inner central pore and side holes. Hence, the augmentation process of FPS is more convenient during operation. The biomechanics of PMMA augmented FPS is strong enough for instrumentation in osteoporotic vertebra body and the way of FPS PMMA augmentation can reduce the risk of PMMA leakage. Conclusion FPS is an innovation in the technology of spinal instrumentation, which is expected to improve the clinical outcome of PMMA augmented pedicle screw in osteoporotic vertebra body fixation.
ObjectiveTo compare the effective of short-segment pedicle instrumentation with bone grafting and pedicle screw implanting in injured vertebra and cross segment pedicle instrumentation with bone grafting in injured vertebra for treating thoracolumbar fractures. MethodsA prospective randomized controlled study was performed in 40 patients with thoracolumbar fracture who were in accordance with the inclusive criteria between June 2010 and June 2012. Of 40 patients, 20 received treatment with short-segment pedicle screw instrumentation with bone grafting and pedicle screw implanting in injured vertebra in group A, and 20 received treatment with cross segment pedicle instrumentation with bone grafting in injured vertebra in group B. There was no significant difference in gender, age, affected segment, disease duration, Frankel grade, Cobb angle, compression rate of anterior verterbral height, visual analogue scale (VAS) score, and Japanese Orthopaedic Association (JOA) score between 2 groups before operation (P>0.05). The operation time, blood loss, Cobb angle, compression rate of anterior vertebral height, loss of disc space height, Frankel grade, VAS and JOA scores were compared between 2 groups. ResultsThere was no significant difference in the operation time and blood loss between 2 groups (P>0.05). Primary healing of incision was obtained in all patients, and no early complication of infection or lower limb vein thrombus occurred. Forty patients were followed up 12-16 months (mean, 14.8 months). No breaking or displacement of internal fixation was observed. The improvement of Frankel grading score was 0.52±0.72 in group A and 0.47±0.63 in group B, showing no significant difference (t=0.188, P=0.853) at 12 months after operation. The Cobb angle, compression rate of anterior verterbral height, and VAS score at 1 week and 12 months, and JOA score at 12 months were significantly improved when compared with preoperative ones in 2 groups (P<0.05). No significant difference was found in Cobb angle, disc space height, VAS score, and JOA score between 2 groups at each time point (P>0.05), but the compression rate of anterior verterbral height in group A was significantly lower than that in group B (P<0.05). The loss of disc space height next to the internal fixation or the injured vertebra was observed in 2 groups at 12 months, but showing no significant difference (P>0.05). ConclusionCompared with cross segment pedicle instrumentation, short-segment pedicle screw instrumentation with bone grafting and pedicle screw implanting in injured vertebra can recover and maintain the affected vertebra height in treating thoracolumbar fractures, but it could not effectively prevent degeneration of adjacent segments and the loss of kyphosis correction degree.
ObjectiveTo investigate the clinical application of three-dimensional (3D) printing technique combined with a new type of thoracic pedicle screw track detector in thoracic pedicle screw placement.MethodsAccording to the characteristics of thoracic pedicle and common clinical screw placement methods, a new type of thoracic pedicle screw track detector was independently developed and designed. The clinical data of 30 patients with thoracic vertebrae related diseases who underwent posterior thoracic pedicle screw fixation between March 2017 and January 2020 were retrospectively analysed. Among them, there were 18 males and 12 females with an average age of 56.3 years (range, 32-76 years). There was 1 case of thoracic disc herniation, 4 cases of thoracic canal stenosis, 2 cases of ossification of posterior longitudinal ligament of thoracic vertebra, 16 cases of thoracic trauma, 2 cases of thoracic infection, and 5 cases of thoracic canal occupation. Three-dimensional CT of the thoracic vertebra was routinely performed preoperatively, and the model of the patient’s thoracic vertebra was reconstructed and printed out. With the assistance of the model, preoperative simulation was performed with the combination of the new type thoracic pedicle screw track detector, and detected no nails after critical cortical damage. During operation, one side was randomly selected to use traditional hand screws placement (control group), and the other side was selected to use 3D printing technique combined with new type thoracic pedicle screw track detector to assist thoracic pedicle screws placement (observation group). The single screw placement time, adjustment times of single screw, and blood loss during screw placement were compared between the two groups. The accuracy of screw placement in the two groups was evaluated according to postoperative CT imaging data.ResultsThe single screw placement time, adjustment times of single screw, and blood loss during screw placement in the observation group were significantly less than those in the control group (P<0.05). Postoperative CT examination showed that the observation group had 87 screws of grade 1, 3 screws of grade 2, and the acceptable screw placement rate was 100% (90/90); the control group had 76 screws of grade 1, 2 screws of grade 2, 11 screws of grade 3, and 1 screw of grade 4, and the acceptable screw placement rate was 86.7% (78/90); showing significant difference in screw placement between the two groups (χ2=12.875, P=0.001). All patients were followed up 6-18 months, with an average of 11.3 months. There was no complication of vascular, nerve, spinal cord, or visceral injury, and screws or rods broken, and no patient was revised.ConclusionThe 3D printing technique combined with the new type of thoracic pedicle screw track detector assisted thoracic pedicle screw placement is convenient, and significantly improves the accuracy and safety of intraoperative screw placement, and overall success rate of the surgery.
Objective To compare the effectiveness of cortical bone trajectory screw (CBTS) and conventional pedicle screw for posterior lumbar interbody fusion (PLIF) in the treatment of single segment lumbar degenerative disease. Methods Between May 2013 and May 2016, a total of 97 patients with single segment lumbar degenerative disease were treated with PLIF. Fifty-one patients were fixed with CBTS in PLIF (trajectory screw group) and 46 with pedicle screw (pedicle screw group). There was no significant difference in age, gender, body mass index, preoperative diagnosis, lesion segment, and preoperative visual analogue scale (VAS) score, Oswestry dysfunction index (ODI) between 2 groups (P>0.05). The operation time, intraoperative blood loss, postoperative drainage, bed rest time, length of hospital stay, serum creatine kinase (CK) concentration, total amount of diclofenac sodium, perioperative complications, ODI, VAS score, and interbody fusion rate were recorded and compared between 2 groups. Results All patients were followed up 12 months. The patients in trajectory screw group had a significantly less operation time, intraoperative blood loss, postoperative drainage, and serum CK concentration when compared with the patients in pedicle screw group (P<0.05). Thirty-five patients (68.6%) in trajectory screw group and 46 patients (100%) in pedicle screw group were given diclofenac sodium within 48 hours after operation, showing significant difference between 2 groups (χ2=89.334, P=0.000). There was no significant difference in the incidence of perioperative complications between trajectory screw group and pedicle screw group (3.9% vs. 8.7%, P=0.418). There was no significant difference in the VAS score, ODI, and interbody fusion rate at 12 months after operation between 2 groups (P>0.05). Conclusion For the single segment degenerative lumbar disease, the use of CBTS or conventional pedicle screw for PLIF can obtain satisfactory clinical function and interbody fusion rate. But the former has the advantages of less blood loss, less intraoperative muscle damage, less perioperative pain, shorter length of hospital stay and bed rest time.