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BACKGROUND: The angle of screw placement in anterior cervical discectomy and fusion plays a crucial role in determining the stability of the internal fixation system. OBJECTIVE: To predict the impact of different screw placement angles on the stress experienced by the internal fixation system in anterior cervical discectomy and fusion utilizing finite element analysis, with the ultimate goal of identifying the optimal screw placement angle. METHODS: A three-dimensional reconstruction method was employed to establish a mechanical model of the cervical spine, enabling the simulation of three distinct working conditions: scoliosis, uprightness, and forward flexion. In SolidWorks 2017, the anterior cervical plate and screw models were built according to different placement angles of the screws, with a as the inward offset, b as the ideal position, c as the outward offset, d as the downward offset, and e as the upward offset. The stress distribution of internal fixation system at different screw placement angles was observed, and the stress and displacement were recorded. RESULTS AND CONCLUSION: (1) By constructing a finite element model of the entire cervical spine and incorporating an anterior titanium plate, it was found that the biomechanical changes in the spine did not significantly differ based on the various angles of screw insertion on the titanium plate under the same working conditions. (2) However, microscopic analysis revealed that the outward offset (c) screw position exhibited the most effective resistance against side bending, while the downward offset (d) screw demonstrated optimal load-bearing capacity in the upright condition. Additionally, the outward deviation (c) screw displayed superior anti-bending effects in the reverse buckling condition. (3) The fixation effect of the internal fixation device remained relatively stable across different motion conditions. Although there was a 10% variation in the internal fixation effect under the three working conditions when the screw was placed inward, outward, downward, or upward, the displacement changes were minimal. These findings suggest that the requirements of load bearing, bending resistance, and flexion resistance could be simultaneously met without a specific optimal screw location in clinical practice. (4) The placement direction of titanium plate screw in anterior cervical disc-resection and fusion has little effect on the mechanical stability of the cervical spine. The screw angles in different directions have little influence on the stability of the internal fixation device in the lateral, upright, and forward flexion movements of the cervical spine. There is no need to pursue the direction of screw placement in clinical operations. [ABSTRACT FROM AUTHOR]

(1) Background: Our team has previously introduced the Single-Step Pedicle Screw System (SSPSS), which eliminates the need for K-wires, as a safe and effective method for percutaneous minimally invasive spine (MIS) pedicle screw placement. Despite this, there are ongoing concerns about the reliability and accuracy of screw placement in MIS procedures without traditional tools like K-wires and Jamshidi needles. To address these concerns, we evaluated the accuracy of the SSPSS workflow by comparing the planned intraoperative screw trajectories with the final screw positions. Traditionally, screw placement accuracy has been assessed by grading the final screw position using postoperative CT scans. (2) Methods: We conducted a retrospective review of patients who underwent lumbar interbody fusion, using intraoperative 3D navigation for screw placement. The planned screw trajectories were saved in the navigation system during each procedure, and postoperative CT scans were used to evaluate the implanted screws. Accuracy was assessed by comparing the Gertzbein and Robbins classification scores of the planned trajectories and the final screw positions. Accuracy was defined as a final screw position matching the classification of the planned trajectory. (3) Results: Out of 206 screws, 196 (95%) were accurately placed, with no recorded complications. (4) Conclusions: The SSPSS workflow, even without K-wires and other traditional instruments, facilitates accurate and reliable pedicle screw placement. [ABSTRACT FROM AUTHOR]

Objective: To compare the differences between Ultrasound Volume Navigation (UVN), O-arm Navigation, and conventional X-ray fluoroscopy-guided screw placement in Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) surgeries. Methods: A total of 90 patients who underwent MIS-TLIF due to lumbar disc herniation from January 2022 to January 2023 were randomly assigned to the UVN group, O-arm group, and X-ray group. UVN, O-arm navigation, and X-ray guidance were used for screw placement in the respective groups, while the remaining surgical procedures followed routine MIS-TLIF protocols. Intraoperative data including average single screw placement time, total radiation dose, and average effective radiation dose per screw were recorded and calculated. On the 10th day after surgery, postoperative X-ray and CT examinations were conducted to assess screw placement accuracy and facet joint violation. Results: There were no significant differences in general characteristics among the three groups, ensuring comparability. Firstly, the average single screw placement time in the O-arm group was significantly shorter than that in the UVN group and X-ray group (P<0.05). Secondly, in terms of total radiation dose during surgery, for single-level MIS-TLIF, the O-arm group had a significantly higher radiation dose compared to the UVN group and X-ray group (P<0.05). However, for multi-level MIS-TLIF, the X-ray group had a significantly higher radiation dose than the O-arm group and UVN group (P<0.05). In terms of average single screw radiation dose, the O-arm group and X-ray group were similar (P>0.05), while the UVN group was significantly lower than the other two groups (P<0.05). Furthermore, no significant differences were found in screw placement assessment grades among the three groups (P>0.05). However, in terms of facet joint violation rate, the UVN group (10.3%) and O-arm group (10.7%) showed no significant difference (P>0.05), while the X-ray group (26.7%) was significantly higher than both groups (P<0.05). Moreover, in the UVN group, there were significant correlations between average single screw placement time and placement grade with BMI index (r = 0.637, P<0.05; r = 0.504, P<0.05), while no similar significant correlations were found in the O-arm and X-ray groups. Conclusion: UVN-guided screw placement in MIS-TLIF surgeries demonstrates comparable efficiency, visualization, and accuracy to O-arm navigation, while significantly reducing radiation exposure compared to both O-arm navigation and X-ray guidance. However, UVN may be influenced by factors like obesity, limiting its application. [ABSTRACT FROM AUTHOR]

Objective: Intra-articular screw penetration is a probable complication of coronoid fracture fixation. Thepresent study aimed to determine the best radiography technique for visualizing the proximal radioulnar joint(PRUJ) space. Moreover, it aimed to determine the safe angle and length of the screw to avoid PRUJ penetrationduring coronoid fracture fixation.Methods: The Mimics software was used to construct a three-dimensional model of a healthy man’s forearmfrom a computer tomography scan. It was analyzed using the Solidworks software to determine the X-ray anglethat clearly showed the PRUJ space to detect penetration of screws from the coronoid process into the PRUJand determine the maximum screw angle and length that could be used without intra-articular penetration. Toverify these findings, a cadaveric study combined with radiographs was conducted.Results: To visualize PRUJ space, the optimal X-ray angle was 13º lateral to the perpendicular line when theforearm was positioned at full supination. If the coronoid process was segmented into zones 1 (closest to theradioulnar joint) to 4 (farthest from the joint), the screw could only be inserted at a right angle in zone 1. In zones2, 3, and 4, inclination angles less than 15, 35, and 60 would prevent intra-articular penetration, respectively.Conclusions: The X-rays could visualize the PRUJ space with an anteroposterior radiograph at an angle of13º ulnar deviation from the perpendicular plane. During coronoid process fracture fixation, shorter screwswith less lateral inclination were safer when inserting screws in the zones of the coronoid process adjacent tothe PRUJ.

BACKGROUND: Orthopedic robots have been widely used in clinical practice, and relevant reports have shown that they have many advantages such as minimal trauma and short surgical time. However, there is currently no clear report on how accurate they are. OBJECTIVE: To evaluate the accuracy of robot-assisted sacroiliac screw insertion. METHODS: A total of 131 patients with sacroiliac joint fracture and dislocation and sacral fracture admitted to the Department of Trauma Surgery, Gansu Provincial Hospital from January 2020 to April 2023 were retrospectively collected, including 131 S1 screws and 46 S2 screws, totaling 177 screws. They were divided into two groups based on whether robot-assisted navigation was performed. There were 63 cases of sacroiliac screws inserted under robot-assisted navigation (observation group), with 36 males and 27 females, aged 19-72 years, with a mean age of (45.3±17.6) years. Among them, 39 cases were fixed with only S1 screws, while 24 cases were fixed with S1S2 screws, resulting in a total of 87 sacroiliac screws. Under C-arm fluoroscopy, 68 cases of sacroiliac screws were inserted with bare hands (control group), including 41 males and 27 females, aged 23-67 years, with a mean age of (42.6±21.3) years. Among them, 46 cases were fixed with simple S1 screws, while 22 cases were fixed with S1S2 screws, resulting in a total of 90 sacroiliac screws. A postoperative CT scan was performed to evaluate the number of S1 screws, S2 screws, total screw level, and calculate accuracy based on the method introduced by SMITH et al. RESULTS AND CONCLUSION: (1) In the observation group, 62 S1 screws were accurately placed (62/63), with an accuracy rate of 98%. 24 S2 screws were accurately placed (24/24), with an accuracy rate of 100%. The total number of screws accurately placed was 86 (86/87), with an accuracy rate of 99%. (2) In the control group, 58 S1 screws were accurately inserted (58/68), with an accuracy rate of 85%. 19 S2 screws were accurately inserted (19/22), with an accuracy rate of 86%. The total number of screws accurately inserted was 77 (77/90), with an accuracy rate of 86%. (3) There was a statistically significant difference in the accuracy of the S1 screw, S2 screw, and total screw between the two groups (P < 0.05). It is suggested that the placement of sacroiliac screws under robot navigation has higher accuracy compared to manual placement under C-arm fluoroscopy, but still has a lower error rate in placement. [ABSTRACT FROM AUTHOR]

Pedicle screws are commonly used for posterior fixation of the lumbar spine. Inaccuracy of screw placement can lead to disastrous complications. As fluoroscopic assisted pedicle screw instrumentation is the most frequently used technique, the aim of this study was to assess the specificity, sensitivity and accuracy of intraoperative fluoroscopy to detect mediolateral screw malpositioning. We also analyzed whether the addition of an oblique view could improve these parameters. On 12 human cadavers, 138 pedicle screws were placed intentionally either with 0 to 2 mm (75 screws), with 2 to 4 mm (six medial and 12 lateral screws) and with >4 mm (22 medial and 23 lateral screws) breach of the pedicle from Th12 to L5. Three experienced spine surgeons evaluated the screw positioning in fluoroscopic AP views and 4 weeks later in AP views and additional oblique views. The surgeons' interpretation was compared with the effective screw position on postoperative CT scans. Pedicle breaches greater than 2 mm were detected in 68% with AP views and in 67% with additional oblique views (p=.742). The specificity of AP views was 0.86 and 0.93 with additional oblique views (p=<.01). The accuracy was 0.78 with AP views and 0.81 with AP + oblique views (p=.114). There was a substantial inter-reader agreement (Fleiss's kappa: 0.632). Fluoroscopic screening of pedicle screw misplacement has a limited sensitivity. Adding an oblique view improves specificity but not sensitivity and accuracy in detecting screw malpositions. When in doubt of a screw malpositioning, other modalities than a fluoroscopic assisted pedicle screw instrumentation such as intraoperative CT imaging or an intraoperative exploration of the screw trajectory must be evaluated. [ABSTRACT FROM AUTHOR]

With the development of artificial intelligence and the further deepening of medical-engineering integration, spine surgical robot-assisted (RA) technique has made significant progress and its applicability in clinical practice is constantly expanding in recent years. In this review, we have systematically summarized the majority of literature related to spine surgical robots in the past decade, and not only classified robots accordingly, but also summarized the latest research progress in RA technique for screw placement such as cervical, thoracic, and lumbar pedicle screws, cortical bone trajectory screws, cervical lateral mass screws, and S2 sacroiliac screws; guiding targeted puncture and placement of endoscope via the intervertebral foramen; complete resection of spinal tumor tissue; and decompressive laminectomy. In addition, this report also provides a detailed evaluation of RA technique’s advantages and disadvantages, and clarifies the accuracy, safety, and practicality of RA technique. We consider that this review can help clinical physicians further understand and familiarize the current clinical application status of spine surgical robots, thereby promoting the continuous improvement and popularization of RA technique, and ultimately benefiting numerous patients.

(1) Background: Our team has previously introduced the Single-Step Pedicle Screw System (SSPSS), which eliminates the need for K-wires, as a safe and effective method for percutaneous minimally invasive spine (MIS) pedicle screw placement. Despite this, there are ongoing concerns about the reliability and accuracy of screw placement in MIS procedures without traditional tools like K-wires and Jamshidi needles. To address these concerns, we evaluated the accuracy of the SSPSS workflow by comparing the planned intraoperative screw trajectories with the final screw positions. Traditionally, screw placement accuracy has been assessed by grading the final screw position using postoperative CT scans. (2) Methods: We conducted a retrospective review of patients who underwent lumbar interbody fusion, using intraoperative 3D navigation for screw placement. The planned screw trajectories were saved in the navigation system during each procedure, and postoperative CT scans were used to evaluate the implanted screws. Accuracy was assessed by comparing the Gertzbein and Robbins classification scores of the planned trajectories and the final screw positions. Accuracy was defined as a final screw position matching the classification of the planned trajectory. (3) Results: Out of 206 screws, 196 (95%) were accurately placed, with no recorded complications. (4) Conclusions: The SSPSS workflow, even without K-wires and other traditional instruments, facilitates accurate and reliable pedicle screw placement.

Aim: Screw used in the treatment of ankle syndesmosis diastasis can be placed in malposition. Our aim in the study is to define a new technique for sending the screws in the right direction. Materials and Methods: The ankle tomography of 188 patients was evaluated. First, the medial malleolus root was divided into three equal parts in axial CT section. Then, a screw model was drawn to fit the fibula to the concave surface in the tibia in another axial CT section where the syndesmosis joint is prominent. These two axial CT sections were placed on top of each other with computer program. Results are noted. Results: While 95.7% of the screw simulations were passing through the front 1/3, 4.3% through the middle 1/3, the screw did not pass through the rear 1/3 in any simulation. 187 of these lines passed between the most lateral peak of the fibula and 3 mm posterior. Conclusion: During diastasis surgery, the insertion site of the drill should be chosen between the sharp peak of the fibula and the 3mm posterior. When the drill is placed in this way and directed 1/3 anterior to the medial malleolus, our screw will be sent in the correct position. Our study revealed that the surgical treatment of syndesmos dissociation with screws is a landmark independent of the patient's position and the skill of the surgeon. There is no other study like this study. However, considering the consistency of our results with the literature, we believe that our study can guide surgeons in practical applications. [ABSTRACT FROM AUTHOR]

Background: A very common technique for treating spinal deformities in children and adolescents is the use of segmental screws. In order to obtain proper stability and the best possible correction, the screws must first be precisely inserted. Additional factors influencing the quality and success of the operation are the size and quality of the bone, the skills of the surgeon, and biomechanical factors, i.e., the width and length of the screws used during surgery. Our study was focused on evaluating the effect of increasing the diameter of the instrumented pedicles by pedicle screws and assessing the safety of expanding these pedicles with screws of various sizes in children with spinal deformities during the growth period, using preoperative magnetic resonance imaging and postoperative computed tomography (CT) to assess and compare preoperative size measurements from MRI to postoperative CT measurements. Methods: We obtained data for evaluation from the available medical records and treatment histories of patients aged 2 to 18 who underwent surgical treatment of spinal deformities in the years 2016–2023. In 230 patients (28 male and 202 female), 7954 vertebral bodies were scanned by preoperative MRI, and 5080 pedicle screws were inserted during surgery, which were then assessed by postoperative CT scan. For the most accurate assessment, patients were classified into three age groups: 2–5 years (Group 1), 6–10 years (Group 2), and 11–18 years (Group 3). In addition, we studied implant subgroups: vertebral bodies with inserted pedicles of screw sizes 5.0 mm and 5.5 mm (Group S), and pedicles of screw sizes 6.0 mm, 6.5 mm, and 7.0 mm (Group L). Results: The morphology of pedicles (Lenke classification) analyzed before surgery using MRI was 55.2% type A, 33.8% type B, 4.7% type C, and 6.3% type D. The postoperative lateral and medial breaches were noted, and these did not cause any complications requiring revision surgery. The mean pedicle diameter before surgery for T1–L5 vertebral pedicles was between 3.79 (1.44) mm and 5.68 (1.64) mm. The mean expanding diameter of pedicles after surgery for T1–L5 vertebral pedicles ranged from 1.90 (0.39) mm to 2.92 (0.28) mm, which corresponds to the extension of the pedicle diameter in the mean range of 47% (4.1)–71% (3.0). We noted that the mean vertebral pedicle expansion was 49% in Group 1, 52% in Group 2, and 62% in Group 3 (N.S.), and the mean expansion for 7.0 mm screw pedicles was 78%. Conclusions: Our study confirms that there is a wide range of expansion of the vertebral pedicle during screw insertion (up to 78%) with a low risk of lateral or medial breaches and without an increased risk of complications. The larger the diameter of the screw inserted into the pedicle, the more the pedicle expands. Pedicle measurements by preoperative MRI may be helpful for sufficient reliability in preoperative planning. [ABSTRACT FROM AUTHOR]

Background: The current method of treatment of spinal deformities would be almost impossible without pedicle screws (PS) placement. There are only a few studies evaluating the safety of PS placement and possible complications in children during growth. The present study was carried out to evaluate the safety and accuracy of PS placement in children with spinal deformities at any age using postoperative computed tomography (CT) scans. Methods: 318 patients (34 males and 284 females) who underwent 6358 PS fixations for pediatric spinal deformities were enrolled in this multi-center study. The patients were divided into three age groups: less than 10 years old, 11–13 years old, and 14–18 years old. These patients underwent postoperative CT scans and were analyzed for pedicle screw malposition (anterior, superior, inferior, medial, and lateral breaches). Results: The breach rate was 5.92% for all pedicles. There were 1.47% lateral and 3.12% medial breaches for all pedicles with tapping canals, and 2.66% lateral and 3.84% medial breaches for all pedicles without a tapping canal for the screw. Of the 6358 screws placed in the thoracic, lumbar, and sacral spine, 98% of the screws were accurately placed (grade 0, 1, and juxta pedicular). A total of 56 screws (0.88%) breached more than 4 mm (grade 3), and 17 (0.26%) screws were replaced. No new and permanent neurological, vascular, or visceral complications were encountered. Conclusions: The free-hand technique for pedicle screw placement in the acceptable and safety zone in pedicles and vertebral bodies was 98%. No complications associated with screw insertion in growth were noted. The free-hand technique for pedicle screw placement can be safely used in patients at any age. The screw accuracy does not depend on the child's age nor the size of the deformity curve. Segmental instrumentation with posterior fixation in children with spinal deformities can be performed with a very low complication rate. Navigation of the robot is only an auxiliary tool in the hands of the surgeons, and the result of the work ultimately depends on the surgeons. [ABSTRACT FROM AUTHOR]

Abstract Introduction Calcaneal fractures, especially those involving the articular surface, should be anatomically reduced as much as possible. Fixing the fracture by placing a screw into the sustentaculum tali from the lateral side of the calcaneus is generally considered to be the key to successful surgery. However, due to the limited visibility during surgery, it is not easy to place screws into the sustentaculum tali accurately. The purpose of this study was to explore a new fluoroscopy method for the sustentaculum tali and verify the value of this method in improving screw placement accuracy. Methods In this study, a total of 42 human foot and ankle specimens were dissected and measured. The shape and position of the sustentaculum tali were observed, and the influence of adjacent bones on imaging findings was analysed. The axial and frontal X-ray fluoroscopy method to view the sustentaculum tali was formulated, and the appropriate projection angle through anatomical and image measurements was explored. Thirty specimens were randomly selected for screw placement, and the direction of the screw was dynamically adjusted under the new imaging method. The success rate of sustentacular screw placement was evaluated. Results The anteversion angles of the sustentaculum tali were 30.81 ± 2.21° and 30.68 ± 2.86° by anatomical and imaging measurements, respectively. There was no statistically significant difference in the anteversion angle between the two measurement methods. Harris heel views should be obtained at 30° to identify the sustentaculum tali on axial X-ray images. Frontal X-ray imaging was performed perpendicular to this projection angle. Through frontal and axial X-ray imaging, the position and shape of the sustentaculum tali can be clearly observed, and these factors are seldom affected by adjacent bones. Under the new fluoroscopy method, the screws were placed from the anterior region of the lateral wall of the calcaneus to the sustentaculum tali. A total of 60 screws were placed in the 30 specimens; of these, 54 screws were in good position, 2 screws penetrated the cortical bone, and 4 screws did not enter the sustentaculum tali. The success rate of sustentacular screw placement was 90% (54/60). Conclusions Axial and frontal X-ray images of the sustentaculum tali can clearly show the shape of the structure, which improves sustentacular screw placement accuracy.

Background Atlantoaxial instability is an important disorder that causes serious symptoms such as difficulties in walking, limited neck mobility, sensory deficits, etc. Atlantal lateral mass screw fixation is a surgical technique that has gained important recognition and popularity. Because accurate drilling area for screw placement is of utmost importance for a successful surgery, we aimed to investigate morphometry of especially the posterior part of C1. Methods One hundred and fifty-eight human adult C1 dried vertebrae were obtained. Measurements were performed directly on dry atlas vertebrae, and all parameters were measured by using a digital caliper accurate to 0.01 mm for linear measurements. Results The mean distance between the tip of the posterior arch and the medial inner edge of the groove was found to be 10.59 ± 2.26 and 10.49 ± 2.20 mm on the right and left, respectively. The mean distance between the tip of the posterior arch and the anterolateral outer edge of the groove was 21.27 ± 2.28 mm (right: 20.96 ± 2.22 mm; left: 21.32 ± 2.27 mm). The mean height of the screw entry zone on the right and left sides, respectively, were 3.86 ± 0.81 and 3.84 ± 0.77 mm. The mean width of the screw entry zone on both sides was 13.15 ± 1.17 and 13.25 ± 1.3 mm. Conclusion Our result provided the literature with a detailed database for the morphometry of C1, especially in relation to the vertebral artery groove. We believe that the data in the present study can help surgeons to adopt a more accurate approach in terms of accurate lateral mass screw placement in atlantoaxial instability. [ABSTRACT FROM AUTHOR]

Abstract Background The objective of the study was to explore the feasibility and efficacy of computer-assisted screw inserting planning (CASIP) in the surgical treatment for severe spinal deformity. Methods A total of 50 patients participated in this prospective cohort study. 25 patients were allocated into CASIP group and 25 patients were in Non-CASIP group. The demographic data, radiological spinal parameters were documented and analyzed. Each pedicle screw insertion was classified as satisfactory insertion or unsatisfactory insertion based on Gertzbein-Robbins classification. The primary outcome was the accuracy of pedicle screw placement. The secondary outcomes were the rate of puncturing screws, estimated blood loss, surgical time, correction rate and other radiological parameters. Results A total of 45 eligible patients completed the study. 20 patients were in CASIP group and 25 patients were in Non- CASIP group. The accuracy of pedicle screw placement in CASIP Group and Non-CASIP Group were (92.0 ± 5.5) % and (82.6 ± 8.3) % (P

Purpose : Both robots and navigation are effective strategies for optimizing screw placement, as compared to freehand placement. However, few studies have compared the accuracy and efficiency of these two techniques. Thus, the purpose of this study is to compare the accuracy and efficiency of robotic and navigation-assisted screw placement in the spinal vertebrae. Methods: The 24 spine models were divided into a robot- and navigation-assisted groups according to the left and right sides of the pedicle. The C-arm transmits image data simultaneously to the robot and navigates using only one scan. After screw placement, the accuracy of the two techniques were compared using "angular deviation" and "Gertzbein and Robbins scale" in different segments (C1–7, T1–4, T5–8, T9–12, and L1–S1). In addition, operation times were compared between robot- and navigation-assisted groups. Results: Robots and navigation systems can simultaneously assist in screw placement. The robot-assisted group had significantly less angular deviation than the navigation-assisted group from C1 to S1 (p < 0.001). At the C1–7 and T1–4 segments, the robot-assisted group had a higher rate of acceptable screws than the robot-assisted group. However, at the T5–8, T9–12, and L1–S1 segments, no significant difference was found in the incidence of acceptable screws between the two groups. Moreover, robot-assisted screw placement required less operative time than navigation (p < 0.05). Conclusion: The robot is more accurate and efficient than navigation in aiding screw placement. In addition, robots and navigation can be combined without increasing the number of fluoroscopic views. [ABSTRACT FROM AUTHOR]

Abstract Background Three-dimensional (3-D) printed guidance templates are being increasingly used in spine surgery. The purpose of this study was to determine if 3D printed navigation templates can improve the accuracy of pedicle screw placement and decrease the complication rate compared to freehand screw placement in the treatment of children with congenital scoliosis. Methods The records of pediatric patients with congenital scoliosis treated at our hospital from January 2017 to January 2019 were retrospectively reviewed. Patients were divided into those where a 3D printed guidance templated was used and those in which the freehand method was used for pedicle screw placement. The accuracy rate of pedicle screw placement, surgical outcomes, and complications were compared between groups. Results A total of 67 children with congenital scoliosis were included (43 males and 24 females; mean age of 4.13 ± 2.66 years; range, 2–15 years). There were 34 children in the template-assisted group and 33 in the freehand group. The excellent accuracy rate of pedicle screw placement was significantly higher in the template-assisted group (96.10% vs. 88.64%, P = 0.007). The main Cobb angle and kyphosis angle were similar between the 2 groups preoperatively and postoperatively (all, P > 0.05), and in both groups both angles were significantly decreased after surgery as compared to the preoperative values (all, P

Purpose: To provide a baseline for comparison with future advancements, this study determined the accuracy of preoperative planning of pedicle screw placement using standard radiographs for posterior fusion (PSF) for adolescent idiopathic scoliosis (AIS). Methods: Ninety-five patients with AIS planned for PSF were prospectively enrolled. Preoperative planning was based upon standard upright posteroanterior and lateral radiographs. The planned number of screws to be placed at each level was recorded. Intraoperatively, all screws were placed by freehand technique. The number of successfully placed screws and the reasons for abandoning screw placement were documented. Results: There were a total of 1783 pedicle screws planned preoperatively. The average planned implant density was 2.0 implants/vertebra. A total of 1723 (96.6%) of the planned screws were placed successfully. Fourteen (0.8%) screws were abandoned after attempted placement (range 0–2 screws/case). Of 241 screws planned in pedicles noted to be "hypoplastic," 13 resulted in the use of a hook or no instrumentation. The placement was not attempted for 49 (range 0–7/case) planned screws due to intraoperative decision-making and a sense that the curve was flexible enough not to require every screw. Three cases (3.2%) required instrumentation of an additional level. Conclusions: Standard spine radiographs allow for accurate preoperative planning for freehand pedicle screw placement in AIS. Ninety-seven percent of planned screws were placed successfully. The primary reason for deviation from the preoperative plan was intraoperative surgeon decision-making rather than difficulty with screw placement. This study will serve as a baseline when considering the utilization of navigation in PSF for AIS. [ABSTRACT FROM AUTHOR]

Introduction: Calcaneal fractures, especially those involving the articular surface, should be anatomically reduced as much as possible. Fixing the fracture by placing a screw into the sustentaculum tali from the lateral side of the calcaneus is generally considered to be the key to successful surgery. However, due to the limited visibility during surgery, it is not easy to place screws into the sustentaculum tali accurately. The purpose of this study was to explore a new fluoroscopy method for the sustentaculum tali and verify the value of this method in improving screw placement accuracy. Methods: In this study, a total of 42 human foot and ankle specimens were dissected and measured. The shape and position of the sustentaculum tali were observed, and the influence of adjacent bones on imaging findings was analysed. The axial and frontal X-ray fluoroscopy method to view the sustentaculum tali was formulated, and the appropriate projection angle through anatomical and image measurements was explored. Thirty specimens were randomly selected for screw placement, and the direction of the screw was dynamically adjusted under the new imaging method. The success rate of sustentacular screw placement was evaluated. Results: The anteversion angles of the sustentaculum tali were 30.81 ± 2.21° and 30.68 ± 2.86° by anatomical and imaging measurements, respectively. There was no statistically significant difference in the anteversion angle between the two measurement methods. Harris heel views should be obtained at 30° to identify the sustentaculum tali on axial X-ray images. Frontal X-ray imaging was performed perpendicular to this projection angle. Through frontal and axial X-ray imaging, the position and shape of the sustentaculum tali can be clearly observed, and these factors are seldom affected by adjacent bones. Under the new fluoroscopy method, the screws were placed from the anterior region of the lateral wall of the calcaneus to the sustentaculum tali. A total of 60 screws were placed in the 30 specimens; of these, 54 screws were in good position, 2 screws penetrated the cortical bone, and 4 screws did not enter the sustentaculum tali. The success rate of sustentacular screw placement was 90% (54/60). Conclusions: Axial and frontal X-ray images of the sustentaculum tali can clearly show the shape of the structure, which improves sustentacular screw placement accuracy. [ABSTRACT FROM AUTHOR]

Background: The objective of the study was to explore the feasibility and efficacy of computer-assisted screw inserting planning (CASIP) in the surgical treatment for severe spinal deformity.Methods: A total of 50 patients participated in this prospective cohort study. 25 patients were allocated into CASIP group and 25 patients were in Non-CASIP group. The demographic data, radiological spinal parameters were documented and analyzed. Each pedicle screw insertion was classified as satisfactory insertion or unsatisfactory insertion based on Gertzbein-Robbins classification. The primary outcome was the accuracy of pedicle screw placement. The secondary outcomes were the rate of puncturing screws, estimated blood loss, surgical time, correction rate and other radiological parameters.Results: A total of 45 eligible patients completed the study. 20 patients were in CASIP group and 25 patients were in Non- CASIP group. The accuracy of pedicle screw placement in CASIP Group and Non-CASIP Group were (92.0 ± 5.5) % and (82.6 ± 8.3) % (P < 0.05), and the rate of puncturing screws were (0 (0-0)) % and (0 (0-6.25)) % (P < 0.05). The median surgical time were 280.0 (IQR: 260.0-300.0) min and 310 (IQR: 267.5-390.0) min in two group and showed significant statistic difference (P < 0.05).Conclusions: CASIP has good feasibility and can gain a more accurate and reliable instruments fixation, with which spine surgeons can make a detailed and personalized screw planning preoperatively to achieve satisfying screw placement. [ABSTRACT FROM AUTHOR]

Study Design: Cross-sectional analysis of defined parameters of patients who underwent the presented technique. Patients undergoing thoracic spine fixation for various pathologies.Objective: This technique attempts to limit the incision size in extrapleural thoracotomy for multi-level spinal fixation.Summary of Background Data: Dorsal spine is traditionally approached by either transpleural or extrapleural approach. The extrapleural approach carries a limitation of being restricted in number of levels it can address. By incrementally modifying the present technique, we were able to employ the approach in greater number of levels with lesser morbidities.Method: Classical extrapleural thoracotomy approach is employed with incision size limited to the levels of pathology (~5 cm). Thereafter, proper exposure using Kittner dissection and defining of screw entry points follows. Stab incision is made and screws placed percutaneously through a K-wire-defined trajectory.Results: Eighteen patients underwent fixation through this technique, of which 11 were infectious, four were traumatic, and the rest were neoplastic in pathology. None except three patients had ICU stay of more than 1 day. All patients had a pain score of 6 or lower except for two.Conclusion: Combining the technique of percutaneous screw placement with traditional extrapleural thoracotomy reduces the size of the incision, tissue damage, and morbidity while reducing the cost and duration of hospitalization without comprising the extent of pathology that can be dealt with. [ABSTRACT FROM AUTHOR]

Objective: Simulation-based training is a technique, which evokes or replicates substantial aspects of the real world in a fully interactive fashion and replaces and amplifies real experiences with guided ones, which are generally immersive. Materials and Methods: Twenty-five junior surgeons (20 orthopedic, 5 neurosurgeon) who were not involved in previous posterior cervical spine instrumentation participated in this study. Before the procedures, all surgeons received 2-hour lecture about cervical spine anatomy and screw insertion techniques. Group 1 (10 surgeons) underwent virtual reality simulation with haptic feedback for 20 min, group 2 (15 surgeons) were attended video sessions with experienced surgeons for 20 min for posterior cervical instrumentation training. After, all junior surgeons applied C1-2 screw, C3-4-5 lateral mass screws, and C6-7 cervical pedicle screws to saw bones. All saw bones underwent computerized tomography (CT) imaging and a blinded radiologist reviewed the CT images. Results: Group 1 applied 70 screws and group 2 applied 105 screws. Group 1 showed a 12% misplacement ratio, while group 2 showed a 19% misplacement ratio and 4% rate of a possible vertebral artery trace penetration (p=0.026). Conclusion: According to the results acquired from this study, we observed a lower cervical spine screw misplacement ratio in those who trained with VR based haptic enabled simulation before performing cervical posterior instrumentation. [ABSTRACT FROM AUTHOR]

Abstract Background The increased popularity of minimally invasive spinal surgery calls for a revision of guidance techniques to prevent injuries of nearby neural and vascular structures. Lipid content has previously been proposed as a distinguishing criterion for different bone tissues to provide guidance along the interface of cancellous and cortical bone. This study aims to investigate how fat is distributed throughout the spinal column to confirm or refute the suitability of lipid content for guidance purposes. Results Proton density fat fraction (PDFF) was assessed over all vertebral levels for six human cadavers between 53 and 92 years of age, based on fat and water MR images. According to their distance to the vertebra contour, the data points were grouped in five regions of interest (ROIs): cortical bone (−1 mm to 0 mm), pre-cortical zone (PCZ) 1–3 (0–1 mm; 1–2 mm; 2–3 mm), and cancellous bone ( $$\ge $$ ≥ 3 mm). For PCZ1 vs. PCZ2, a significant difference in mean PDFF of between −7.59 pp and −4.39 pp on average was found. For cortical bone vs. PCZ1, a significant difference in mean PDFF of between −27.09 pp and −18.96 pp on average was found. Conclusion A relationship between distance from the cortical bone boundary and lipid content could be established, paving the way for guidance techniques based on fat fraction detection for spinal surgery.

Purpose: Intra-operative image acquisition coupled with navigation aims to increase screw placement accuracy, and it is particularly helpful in complex spinal procedures. The aim of this study is to analyze the accuracy and reliability of posterior atlanto-axial fixation using spinal navigation combined with intra-operative 3D isocentric C-arm. Methods: We retrospectively reviewed all patients presenting with C1–C2 instability and treated by posterior atlanto-axial fixation in our center between December 2016 and September 2018. Screw positioning was guided by intra-operative navigation, registered with surface matching procedure on a previously obtained CT scan and controlled by intra-operative 3D isocentric C-arm. Age, sex, pre- and post-operative neurological status, duration of surgery, presence/absence of vertebral artery injury, and screw placement were retrospectively collected from patients' records. All patients underwent clinical and radiological follow-up at three months after surgery. Radiological assessment of screw positioning was performed by an independent radiologist using the Gertzbein and Robbins grading. Results: N = 11 (7F, 4 M) consecutive patients were included, with a mean age of 72 years (range from 51 to 85). N = 44 navigated screws were inserted and controlled with intra-operative 3D fluoroscopy at the end of the procedure. An acceptable screw positioning (Gertzbein-Robbins grade A and B) was obtained in all cases (100%). No vertebral artery injury was observed. Mean operating time was 123 minutes. At three months, no screw loosening or displacement was observed. Conclusion: In our experience, spinal navigation coupled with intra-operative 3D fluoroscopy proved to be reliable and safe for C1–C2 screw placement. [ABSTRACT FROM AUTHOR]

BACKGROUND: Because of its excellent biomechanical advantages, pedicle screw of subaxial cervical spine is widely used in various cervical spine diseases caused by trauma, tumors and deformities. How to improve the accuracy of nail placement and reduce postoperative complications has been hotspots in the research of the placement technology of the pedicle screw of subaxial cervical spine. OBJECTIVE: To review relevant domestic and foreign articles, to review the related anatomical characteristics of the placement technology of the pedicle screw of subaxial cervical spine, the biomechanical characteristics of pedicle screw of subaxial cervical spine and the research on the screw placement technology in and outside China, and to analyze the advantages and disadvantages of each placement technology. METHODS: Relevant articles in PubMed, Web of Science, CNKI, Wanfang and other databases were searched using “cervical, pedicle” in English, and “cervical vertebrae, pedicle” in Chinese as search terms. Related Chinese articles published from January 2015 to December 2020 and related English articles published in the past 5 years were searched. Finally, 52 articles were included, including 22 Chinese articles and 30 English articles. RESULTS AND CONCLUSION: (1) Regarding the thickness and strength of the cortex, the inner wall of the pedicle was higher than that of the outer wall. The abduction angle of the pedicle gradually decreased from C3-C7. The shape of the pedicle was similar to an ellipsoid. The distance between the upper edge of the pedicle and the upper nerve root gradually increased from C3-C7, and the distance between the lower edge of the pedicle and the inferior nerve root gradually decreased from C3-C7. The anterior lateral wall of the pedicle was close to the vertebral artery; and the anterior medial wall of the pedicle was close to the epidural sinus. (2) The penetrating force of the inner wall of the pedicle was greater than the other three side walls. In terms of direct extraction force, pedicle screws were superior to intervertebral foraminal screws and lateral mass screws. In terms of fatigue extraction force, pedicle screws and intervertebral foraminal screws were better than lateral mass screws. (3) At present, screw placement in posterior route pedicle on subaxial cervical spine mainly included freehand screw placement, computer-assisted screw placement, 3D printing guide-assisted screw placement, and surgical robot-assisted screw placement. However, various screw placement techniques have certain drawbacks. In the future, freehand screw placement technology will still be the mainstream of the subaxial cervical pedicle placement technology. With the improvement of technical level and the support of artificial auxiliary equipment, artificial intelligence assisted screw placement technology will become the future development direction. [ABSTRACT FROM AUTHOR]

Background: Three-dimensional (3-D) printed guidance templates are being increasingly used in spine surgery. The purpose of this study was to determine if 3D printed navigation templates can improve the accuracy of pedicle screw placement and decrease the complication rate compared to freehand screw placement in the treatment of children with congenital scoliosis.Methods: The records of pediatric patients with congenital scoliosis treated at our hospital from January 2017 to January 2019 were retrospectively reviewed. Patients were divided into those where a 3D printed guidance templated was used and those in which the freehand method was used for pedicle screw placement. The accuracy rate of pedicle screw placement, surgical outcomes, and complications were compared between groups.Results: A total of 67 children with congenital scoliosis were included (43 males and 24 females; mean age of 4.13 ± 2.66 years; range, 2-15 years). There were 34 children in the template-assisted group and 33 in the freehand group. The excellent accuracy rate of pedicle screw placement was significantly higher in the template-assisted group (96.10% vs. 88.64%, P = 0.007). The main Cobb angle and kyphosis angle were similar between the 2 groups preoperatively and postoperatively (all, P > 0.05), and in both groups both angles were significantly decreased after surgery as compared to the preoperative values (all, P < 0.001). The degree of change of the Cobb angle of the main curve and kyphosis angle were not significantly different between the 2 groups. There were no postoperative complications in the template group and 4 in the freehand group (0% vs. 12.12%; P = 0.009). All 4 patients with complications required revision surgery. [ABSTRACT FROM AUTHOR]

Copyright of Operative Orthopädie und Traumatologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Direct screw placement for quadrilateral plate fractures in the danger zone of the acetabulum is very difficult. This study was performed to simulate the surgical procedure and try to obtain effective and safe screw angles through the middle window of the ilioinguinal approach in Chinese patients. Methods We randomly collected the pelvic computed tomography (CT) scans of 100 adults. DICOM-formatted CT-scan images were imported into Mimics software. The three-dimensional reconstruction (3D) digital model of the semi-pelvis was established. A 3.5 mm cylinder was used to simulate the pathway of the screw from the designated insertion point. The angles of insertion and intersex differences were explored by statistical analyses. Results The screws could be inserted via three angles: medial inclination, anterior inclination and posterior inclination. The mean minimum medial inclination angle (MIMIA) of insertion point A was 4.96° ± 1.11° in males and 8.66° ± 3.40° in females, and the intersex difference was significant. The mean minimum medial inclination angle (MIMIA) of insertion point B was − 5.31° ± 3.69° in males and 1.75° ± 8.95° in females, and the intersex difference was significant. There were no differences between any of the angles for males and females at insertion point O. Conclusions Preoperative measurement and calculation by digital tools before screw placement for quadrilateral plate fractures of the acetabulum are feasible. Double cortical screws could be placed safely in the danger zone through the middle window of the ilioinguinal approach to increase the stability of the acetabulum.

Little information exists regarding the benefit of computer navigation in shoulder arthroplasty in the clinical setting. This study aimed to quantify how computer navigation affects the number and length of screws used during in vivo reverse total shoulder arthroplasty (RSA) placement. We performed a retrospective review of a research database to identify patients who underwent primary RSA before and after the use of computer navigation between January 1, 2015, and December 31, 2019. One hundred consecutive RSAs were selected from the computer navigation implantation date; then, 100 consecutive sex-matched RSAs were chosen prior to navigation implantation in reverse chronologic order. Baseplate augmentations were chosen based on surgeon discretion, with the goal of restoring version to within 10° of neutral and inclination to neutral or slightly inferior with removal of the smallest amount of subchondral bone possible. Screws were placed with the goal of ≥3 screws with good purchase and were added as needed, with up to 5 screws used. We compared demographic factors, comorbidities, preoperative diagnosis, number of screws, screw length, number of wasted screws, and number of cases with bone graft used behind the baseplate between the 2 groups. We used the χ2 test for bivariate analysis and the Student t test for continuous variables. A total of 200 RSAs were included, with 100 primary RSAs (mean age, 69.3 years) performed prior to computer navigation compared with 100 primary RSAs (mean age, 69.7 years) performed using computer navigation. The total number of screws used in RSAs without computer navigation was 414; the total used in the computer navigation cases was 344. RSAs placed with computer navigation used significantly fewer screws per case (3.4 screws vs. 4.1 screws, P <.001) and had a significantly greater average screw length (35.0 mm vs. 32.6 mm, P <.001). Three screws were implanted in 61% of computer navigation cases vs. 1% of cases without computer navigation (P <.001). Screws ≥ 30 mm in length were more commonly used in patients undergoing RSA using computer navigation (84.6% vs. 73.7%, P <.001). This study shows that computer navigation in RSA leads to longer and fewer glenoid baseplate screws being implanted. Computer navigation appears to assist with better screw placement, which may have similar clinical benefits of better glenoid fixation. Additionally, using fewer screws can save glenoid bone stock, avoid added glenoid stress risers, and decrease operative time. [ABSTRACT FROM AUTHOR]

Introduction: Current high-accuracy image-guided systems for otologic surgery use fiducial screws for patient-to-image registration. Thus far, these systems have only been used in adults, and the safety and efficacy of the fiducial screw placement has not yet been investigated in the pediatric population.Materials and Methods: In a retrospective study, CT image data of the temporal region from 11 subjects meeting inclusion criteria (8–48 months at the time of surgery) were selected, resulting in n = 20 sides. These datasets were investigated with respect to screw stability efficacy in terms of the cortical layer thickness, and safety in terms of the distance of potential fiducial screws to the dura mater or venous sinuses. All of these results are presented as distributions, thickness color maps, and with descriptive statistics. Seven regions within the temporal bone were analyzed individually. In addition, four fiducial screws per case with 4 mm thread-length were placed in an additively manufactured model according to the guidelines for robotic cochlear implantation surgery. For all these screws, the minimal distance to the dura mater or venous sinuses was measured, or if applicable how much they penetrated these structures.Results: The cortical layer has been found to be mostly between 0.7–3.3 mm thick (from the 5th to the 95th percentile), while even thinner areas exist. The distance from the surface of the temporal bone to the dura mater or the venous sinuses varied considerably between the subjects and ranged mostly from 1.1–9.3 mm (from the 5th to the 95th percentile). From all 80 placed fiducial screws of 4 mm thread length in the pediatric subject younger than two years old, 22 touched or penetrated either the dura or the sigmoid sinus. The best regions for fiducial placement would be the mastoid area and along the petrous pyramid in terms of safety. In terms of efficacy, the parietal followed by the petrous pyramid, and retrosigmoid regions are most suited.Conclusion: The current fiducial screws and the screw placement guidelines for adults are insufficiently safe or effective for pediatric patients.

BACKGROUND: In the surgical treatment of spinal deformities and tumors, the firm and stable fixation of the lumbosacral junction is a task that must be completed in the operation, and it is a relatively great challenge. The incidence rate of postoperative complications (such as pseudarthrosis, failure of internal fixation and loosening) is high. The mechanical strength of the bone tissue in the sacrum is low, and the high load in the lumbar vertebrae and pelvis increases the risk of internal fixation pullout, which further leads to the loosening of the instrument. Although there are some of the most effective surgical techniques, the complexity of surgical techniques often leads to unsatisfactory clinical results OBJECTIVE: To summarize the latest research progress on the sacropelvic fixation and clinical applications of the S2 alar iliac (S2AI) screws, and provide a reference for clinical treatment. METHODS: The computer was used to search articles published from 2005 to 2020 in CNKI, Wanfang, and PubMed. The search terms were “S2 alar iliac screw, S2AI, iliac screw, sacropelvic fixation, alar iliac screw” in English and Chinese. Relevant articles were consulted, and finally 43 articles were included for analysis. RESULTS AND CONCLUSION: (1) Sacral pelvic fixation, such as ilium and S2AI screw, was added to the lower end of long segmental fixation of the spine to solve the above-mentioned related complications. (2) S2AI screw placement technique plays an important role in stabilizing sacroiliac joint. Because of its unique screw placement method, it avoids screw dislocation, reduces postoperative sacroiliac joint pain and reduces the risk of reoperation. (3) As a new technology of spinal and pelvic fixation, S2AI screw has many advantages and clinical significance, but due to the complex and diverse structure of sacroiliac joint and individual differences of patients, there are still related problems in clinical application of S2AI screw. [ABSTRACT FROM AUTHOR]

Background: Instrumentation of the lumbosacral region is one of the more challenging regions due to the complex anatomical structures and biomechanical forces. Screw insertion can be done both navigated and based on X-ray verification. In this study, we demonstrate a fast and reliable open, low exposure X-ray-guided technique of iliac screw placement. Methods: Between October 2016 and August 2019, 48 patients underwent sacropelvic fixation in tear-drop technique. Screw insertion was performed in open technique by using an X-ray converter angulated 25-30° in coronal and sagittal view. The anatomical insertion point was the posterior superior iliac spine. Verification of correct screw placement was done by intraoperative 3D scan. Results: In total, 95 iliac screws were placed in tear-drop technique with a correct placement in 98.1%. Conclusions: The tear-drop technique showed a proper screw position in the intraoperative 3D scan and therefore may be considered an alternative technique to the navigated screw placement. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The increased popularity of minimally invasive spinal surgery calls for a revision of guidance techniques to prevent injuries of nearby neural and vascular structures. Lipid content has previously been proposed as a distinguishing criterion for different bone tissues to provide guidance along the interface of cancellous and cortical bone. This study aims to investigate how fat is distributed throughout the spinal column to confirm or refute the suitability of lipid content for guidance purposes.Results: Proton density fat fraction (PDFF) was assessed over all vertebral levels for six human cadavers between 53 and 92 years of age, based on fat and water MR images. According to their distance to the vertebra contour, the data points were grouped in five regions of interest (ROIs): cortical bone (-1 mm to 0 mm), pre-cortical zone (PCZ) 1-3 (0-1 mm; 1-2 mm; 2-3 mm), and cancellous bone ([Formula: see text] 3 mm). For PCZ1 vs. PCZ2, a significant difference in mean PDFF of between -7.59 pp and -4.39 pp on average was found. For cortical bone vs. PCZ1, a significant difference in mean PDFF of between -27.09 pp and -18.96 pp on average was found.Conclusion: A relationship between distance from the cortical bone boundary and lipid content could be established, paving the way for guidance techniques based on fat fraction detection for spinal surgery. [ABSTRACT FROM AUTHOR]

Purpose: Many patients receive magnetic resonance (MR) and computed tomography (CT) scans post-operatively to review screw placement. Traditionally, CT is diagnostic but as metal artefact reduction sequences are advancing in MR, the necessity for both MR and CT scans is questionable. The objective is to establish the statistical agreeability of MR and CT for evaluation of adequate screw placement in posterior lumbar interbody fusion. Methods: This opportunistic retrospective study of 58 patients investigated 297 images of 296 implanted screws. Post-operative MR and CT images were scrutinised for depiction of lumbar pedicle screw position using a 5-point scale. Kappa value for statistical agreeability tested MR against CT. Results: The 297 images of screws resulted in strong to near-perfect agreement between MR and CT (n = 297 k = 0.8042 p < 0.025). MRI resulted in high sensitivity (88.7%) and positive predictive value (78.3%). MRI demonstrated very high specificity (96.2%) and negative predictive value (98.2%). MR depicted screws (mean 12.6 mm diameter, mean 65.3 mm length) with 50% error in diameter and 30% in length from susceptibility artefact compared to manufacturer dimensions (6.5–7.5 mm diameter, 40–50 mm length). Adequate screw placement was high despite this (85.8%). On MR, the cortex border visibility was 60.7% and the spinal canal visibility was 74.6%. Conclusion: There is strong to near-perfect agreement between MR and CT for evaluating adequate screw position in PLIF surgery. MR alone is useful for analyzing screw placement and should be considered first-line imaging in uncomplicated cases with CT analysis reserved for cases of uncertainty. Level of evidence: Level III retrospective cohort study. [ABSTRACT FROM AUTHOR]

Objectives: To develop drill guide templates as an intraoperative guide, and to evaluate the accuracy and safety of screw placement in the lumbosacral junction.Samples: Canine cadaveric specimens of the lumbosacral junction (n = 6), and clinical cases of lumbosacral instability (n = 3).Procedures: Computed tomography data of the lumbosacral region of cadaveric specimens and clinical cases were obtained. The optimum screw trajectories were determined and drill guide templates were fabricated using a three-dimensional printing system. Drill holes were made using the templates in cadaveric specimens and clinical cases, and lumbosacral fixation was performed in clinical cases. Computed tomography images were obtained to compare the planned and postoperative drill hole trajectories, and the accuracy and safety of drilling and screw placement in the lumbosacral junction were evaluated.Results: Thirty-six drill holes were made in cadaveric specimens. The overall mean drill hole deviation was 2.05 ± 1.32 mm. A total of 12 screws were placed in the lumbosacral junctions of three clinical cases. The overall mean drill hole deviation was 2.43 ± 1.09 mm. Clinical signs improved within 2 weeks in the clinical cases. All drill holes were completely located within the bone in cadaveric specimens and clinical cases.Conclusion and Clinical Relevance: The surgical procedures using the drill guide templates were performed safely with good clinical outcomes. The drill guide template system provided useful surgical guidance to safely and precisely perform screw placement for lumbosacral fixation surgery in small dogs.

BACKGROUND: With the development of three-dimensional (3D) printing technology, it has been widely used in spinal surgery. However, whether 3D printing-assisted surgery for lumbar spondylolisthesis has an advantage over traditional surgery is still controversial. OBJECTIVE: To compare the clinical efficacy and safety of 3D printing-assisted versus conventional surgery for the treatment of lumbar spondylolisthesis using system evaluation. METHODS: Randomized controlled trials about 3D printing technology for lumbar spondylolisthesis in CNKI, Wanfang database, CBM, VIP, PubMed, Cochrane Library, Embase, and Web of Science were searched via computer from inception to November 16, 2019. The retrieved literatures were screened according to predefined inclusion and exclusion criteria, and quality evaluation was performed. Then, the available data were extracted and analyzed with the Stata 11.0 software. RESULTS AND CONCLUSION: (1) Six randomized controlled trials including 394 cases were included. Among them, 201 cases were assigned to the 3D printing-assisted group and 193 cases to the conventional group. (2) Meta-analysis results showed that the 3D printing-assisted group proved significantly superior to the conventional group regrading the operation time [WMD=-38.17, 95%CI(-43.93, -32.41), P=0.00], intraoperative blood loss [WMD=-61.61, 95%CI(-69.19, -54.03), P=0.00], the frequency of fluoroscopy [WMD=-4.89, 95%CI(-6.38, -3.41), P=0.00] and the screw placement accuracy [OR=3.89, 95%CI(2.43, 6.25), P=0.00]. (3) However, in terms of the postoperative visual analogue scale scores [WMD=-0.47, 95%CI(-1.21, 0.27), P=0.215], Oswestry disability index [WMD=-1.41, 95%CI(-2.87, 0.05), P=0.058], Japanese Orthopaedic Association scores [WMD=1.02, 95%CI(-0.68, 2.72), P=0.240] and the rate of complications [OR=0.37, 95%CI(0.12, 1.11), P=0.075], no statistically significant differences were found between the two groups. (4) In conclusion, the application of 3D printing technology in the surgical treatment of lumbar spondylolisthesis has the advantage of shortening the operation time, reducing intraoperative blood loss and frequency of fluoroscopy and improving the accuracy of the screw placement. [ABSTRACT FROM AUTHOR]

• The clinical efficacy of the two methods of screw placement was similar. • The incidence of complications was the same for two methods of screw placement. • ACDF (middle vertebra without screw) had shorter screw placement time and less implant cost. The clinical outcomes, radiological parameters, complication rate and the cost of implants in two-level ACDF with and without screws in the intervening segment were compared. A retrospective study of 68 patients who underwent 2-level ACDF from January 2014 to June 2016 was performed. The patients were divided into two groups: ACDF with screws in the intervening vertebra and those without screws in the intervening vertebra. Perioperative factors, clinical outcomes, postoperative complications, radiological parameters, and cost of the implants were evaluated in both groups. No statistical differences in clinical outcomes, operative blood loss, hospital stay, restoration of cervical lordosis or segment height, postoperative complications, and fusion rate were found between the ACDF (middle vertebra with screw) and ACDF (middle vertebra without screw) groups (P > 0.05). But the operative time of added screw placement and cost of implants in the ACDF (middle vertebra without screw) group were significantly less than the ACDF (middle vertebra with screw) group (P < 0.05). Two kinds of screw placement with ACDF were found to be similar in terms of clinical outcomes. However, ACDF (middle vertebra without screw) was found to be superior to ACDF (middle vertebra with screw) in terms of the screw placement time and cost of implants. [ABSTRACT FROM AUTHOR]

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 anti-bending 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). (2) There was no significant difference in visual analogue scale score, Oswestry Disability Index, anterior edge height ratio and kyphosis Cobb angle between the two groups preoperatively and 2 weeks after the operation (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. [ABSTRACT FROM AUTHOR]

Background: Direct screw placement for quadrilateral plate fractures in the danger zone of the acetabulum is very difficult. This study was performed to simulate the surgical procedure and try to obtain effective and safe screw angles through the middle window of the ilioinguinal approach in Chinese patients.Methods: We randomly collected the pelvic computed tomography (CT) scans of 100 adults. DICOM-formatted CT-scan images were imported into Mimics software. The three-dimensional reconstruction (3D) digital model of the semi-pelvis was established. A 3.5 mm cylinder was used to simulate the pathway of the screw from the designated insertion point. The angles of insertion and intersex differences were explored by statistical analyses.Results: The screws could be inserted via three angles: medial inclination, anterior inclination and posterior inclination. The mean minimum medial inclination angle (MIMIA) of insertion point A was 4.96° ± 1.11° in males and 8.66° ± 3.40° in females, and the intersex difference was significant. The mean minimum medial inclination angle (MIMIA) of insertion point B was - 5.31° ± 3.69° in males and 1.75° ± 8.95° in females, and the intersex difference was significant. There were no differences between any of the angles for males and females at insertion point O.Conclusions: Preoperative measurement and calculation by digital tools before screw placement for quadrilateral plate fractures of the acetabulum are feasible. Double cortical screws could be placed safely in the danger zone through the middle window of the ilioinguinal approach to increase the stability of the acetabulum. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: Intra-articular screw penetration is a probable complication of coronoid fracture fixation. The present study aimed to determine the best radiography technique for visualizing the proximal radioulnar joint (PRUJ) space. Moreover, it aimed to determine the safe angle and length of the screw to avoid PRUJ penetration during coronoid fracture fixation., Methods: The Mimics software was used to construct a three-dimensional model of a healthy man's forearm from a computer tomography scan. It was analyzed using the Solidworks software to determine the X-ray angle that clearly showed the PRUJ space to detect penetration of screws from the coronoid process into the PRUJ and determine the maximum screw angle and length that could be used without intra-articular penetration. To verify these findings, a cadaveric study combined with radiographs was conducted., Results: To visualize PRUJ space, the optimal X-ray angle was 13º lateral to the perpendicular line when the forearm was positioned at full supination. If the coronoid process was segmented into zones 1 (closest to the radioulnar joint) to 4 (farthest from the joint), the screw could only be inserted at a right angle in zone 1. In zones 2, 3, and 4, inclination angles less than 15, 35, and 60 would prevent intra-articular penetration, respectively., Conclusions: The X-rays could visualize the PRUJ space with an anteroposterior radiograph at an angle of 13º ulnar deviation from the perpendicular plane. During coronoid process fracture fixation, shorter screws with less lateral inclination were safer when inserting screws in the zones of the coronoid process adjacent to the PRUJ., Competing Interests: The authors do not have any potential conflicts of interest concerning this manuscript., (© Bulletin of Emergency And Trauma (BEAT).)

With the development of artificial intelligence and the further deepening of medical-engineering integration, spine surgical robot-assisted (RA) technique has made significant progress and its applicability in clinical practice is constantly expanding in recent years. In this review, we have systematically summarized the majority of literature related to spine surgical robots in the past decade, and not only classified robots accordingly, but also summarized the latest research progress in RA technique for screw placement such as cervical, thoracic, and lumbar pedicle screws, cortical bone trajectory screws, cervical lateral mass screws, and S2 sacroiliac screws; guiding targeted puncture and placement of endoscope via the intervertebral foramen; complete resection of spinal tumor tissue; and decompressive laminectomy. In addition, this report also provides a detailed evaluation of RA technique's advantages and disadvantages, and clarifies the accuracy, safety, and practicality of RA technique. We consider that this review can help clinical physicians further understand and familiarize the current clinical application status of spine surgical robots, thereby promoting the continuous improvement and popularization of RA technique, and ultimately benefiting numerous patients.