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BACKGROUND: For thoracolumbar spine fractures with developmental stenosis of the vertebral arch, accurate nail placement is difficult using traditional fluoroscopy-assisted techniques. O-arm navigation assistance systems offer higher precision in general vertebral arch nail placement, but there is scarce literature on the application of O-arm navigation-assisted nail placement in thoracolumbar spine fractures with developmental stenosis of the vertebral arch both domestically and abroad. OBJECTIVE: To explore the accuracy of percutaneous vertebral arch nail placement assisted by O-arm navigation in patients with thoracolumbar spine fractures complicated by developmental stenosis of the vertebral arch. METHODS: A retrospective analysis was conducted on 53 patients who underwent percutaneous vertebral arch screw fixation surgery at Department of Orthopedics, General Hospital of Central Theater Command of PLA for thoracolumbar spine fractures complicated by developmental stenosis of the vertebral arch from January 2021 to March 2023. Totally 208 cases of vertebral arch developmental stenosis were found (cases with multiple vertebral arch developmental stenosis were counted separately). Based on the surgical approach, the patients were divided into two groups: O-arm navigation group (n=98) and C-arm fluoroscopy group (n=110). Postoperative imaging data were compared between the two groups, including anatomical perforation score, functional perforation score, actual vs. expected nail trajectory in the horizontal plane, and sagittal plane angle differences. RESULTS AND CONCLUSION: (1) There was no significant difference in the narrowest width of the pedicle isthmus (pow) between the two groups of patients (P > 0.05). The proportions of different degrees of narrowing (mild: 6 mm≤pow<7 mm, moderate: 5 mm≤pow<6 mm, severe: pow<5 mm) were also not significantly different between the two groups (P > 0.05). (2) The overall grade and scores of anatomical perforation and functional perforation were lower in the O-arm group compared to the C-arm group, and these differences were statistically significant (P < 0.001). In terms of the angular deviation between the actual and planned screw trajectories, the O-arm group had smaller deviations, and these differences were statistically significant (P < 0.05). (3) In the mild and moderate narrowing groups, the O-arm group showed significant advantages in anatomical perforation, functional perforation, and angular deviation between actual and planned screw trajectories, and these differences were statistically significant (P < 0.001). (4) The O-arm group demonstrated better performance in anatomical perforation and functional perforation, especially in the T12-L2 segment, with more significant advantages. Additionally, the O-arm group had better angular deviations in actual and planned screw trajectories in all segments compared to the C-arm group. (5) Therefore, the use of O-arm navigation-assisted percutaneous screw placement for the treatment of thoracolumbar fractures with developmental pedicle isthmal narrowing provides higher accuracy and safer surgery. [ABSTRACT FROM AUTHOR]

Background: Carbon-fiber-reinforced polyether ether ketone (CF-PEEK) is a radiolucent, non-metallic implant material used for instrumented lumbar spondylodesis. Clinical studies of pedicle screw systems employing this material, especially for degenerative indications, are scant. Methods: We conducted a multicenter, prospective clinical study to assess clinical and radiographic outcomes in patients with symptomatic degenerative lumbar disk disease, including degenerative spondylolisthesis treated with a CF-PEEK pedicle screw and a transforaminal lumbar interbody fusion (TLIF) cage system. We followed up the participants for two years postoperatively to collect clinical data (via the Oswestry Disability Index, Core Outcome Measures Index, and Visual Analog Scale), radiographic parameters (functional X-rays) to assess fusion status, and any complications. Results: In total, 86 patients were recruited. During the study, 21 patients (24.4%) dropped out, including 5 (5.8%) who underwent explantation of the study device(s). At the final follow-up, the fusion rate was 98.6% (95% confidence interval, 92.7–100.0%). All clinical parameters improved significantly. There were no complications potentially attributed to the implant material. Conclusions: The results demonstrate a fusion rate similar to that of metallic implant systems with the use of a CF-PEEK pedicle screw and a TLIF cage system. Further studies with larger samples are needed to substantiate this finding. Trial registration: The study was registered at ClinicalTrials.gov (NCT02087267). Date of registration: March 12, 2014. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective cohort study. Objective: The purpose of this study was to see whether upgrades in newer generation robots improve safety and clinical outcomes following spine surgery. Methods: All patients undergoing robotic-assisted spine surgery with the Mazor X Stealth EditionTM (Medtronic, Minneapolis, MN) from 2019 to 2022 at a combined orthopedic and neurosurgical spine service were retrospectively reviewed. Robot related complications were recorded. Results: 264 consecutive patients (54.1% female; age at time of surgery 63.5 ± 15.3 years) operated on by 14 surgeons were analyzed. The average number of instrumented levels with robotics was 4.2 ± 2.7, while the average number of instrumented screws with robotics was 8.3 ± 5.3. There was a nearly 50/50 split between an open and minimally invasive approach. Six patients (2.2%) had robot related complications. Three patients had temporary nerve root injuries from misplaced screws that required reoperation, one patient had a permanent motor deficit from the tap damaging the L1 and L2 nerve roots, one patient had a durotomy from a misplaced screw that required laminectomy and intra-operative repair, and one patient had a temporary sensory L5 nerve root injury from a drill. Half of these complications (3/6) were due to a reference frame error. In total, four patients (1.5%) required reoperation to fix 10 misplaced screws. Conclusion: Despite newer generation robots, robot related complications are not decreasing. As half the robot related complications result from reference frame errors, this is an opportunity for improvement. [ABSTRACT FROM AUTHOR]

Background: Lumbar posterolateral fusion (PLF) with Pedicle Screw-Plate (PSP) fixation without interbody fusion found spontaneous anterior fusion (SAF). No study has reported the SAF of lumbar spine in patients who underwent PLF. This study reports the rate of SAF of lumbar spine after PLF with PSP system compared with the rate of SAF after PLF with pedicle screw-rod (PSR) system. Methods: Retrospective reviews of charts and radiographs were performed in 111 patients who underwent PLF with PSP system and PSR system for treatment of degenerative lumbar spine. Demographic data, diagnosis, Meyerding grading, level of fusion, Pfirrmann grading, disc height, pedicle screw depth, follow-up time and SAF were compared between PSP and PSR groups. Results: Fifty-five patients in the PSP group and 56 patients in the PSR group were included with similar baseline characteristics. There were more degenerative spondylolisthesis patients in the PSP group compared with patients in the PSR group. However, there was no significant difference of Pfirrmann grading in both groups. Fifteen patients (27.3%) in the PSP group developed SAF while no patient in the PSR group had SAF. When patients in the PSP group were analyzed, the mean follow-up time in patients with SAF was significantly longer than the no SAF group. Conclusion: This study has reported SAF of lumbar spine in patients who underwent PLF with the PSP system. The SAF increasingly occurred with longer follow-up time. In this study, no SAF was found in patients who underwent PLF with the PSR system. [ABSTRACT FROM AUTHOR]

Introduction: The minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) that adopts paramedian incisions and tubular retractors to perform the decompression and interbody fusion has been widely used in the surgery for lumber degenerative disease (LDD). Bilateral pedicle screw fixation (BPSF) and unilateral pedicle screw fixation (UPSF) are the primary fixing techniques in MIS-TLIF. We conducted an updated systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the efficacy and safety between UPSF and BPSF in patients undergoing MIS-TLIF surgery for LDD. Materials and methods: We searched the PubMed, Embase, and Cochrane Library databases for potential RCTs till June 2023. The effects of the fixation methods on clinical outcomes were estimated using the odd ratio (RR), risk difference (RD), and mean difference (MD) with a 95% confidence interval (CI) and a random-effects model. Results: We obtained six RCTs. There was no significant difference between UPSF and BPSF in fusion rate, hospitalization day, low back pain, leg pain, Oswestry Disability Index, and SF-36 for physical functioning at 3–6 months and ≥ 6 months after surgery. Neither the total complication nor the individual complications showed differences between the two methods. However, UPSF significantly decreased operation time (MD = − 39.05; 95% CI: − 53.50 to − 24.67) and estimated blood loss (MD = − 60.41; 95% CI: − 79.09 to − 41.73) compared with BPSF. Conclusion: UPSF is better than BPSF when operation time and estimated blood loss are considered. BPSF may be considered for patients with single-level LDD without high-grade spondylolisthesis. [ABSTRACT FROM AUTHOR]

Background: In atlantoaxial instabilities, posterior C1/C2 fusion using lateral mass screws (LMS) or pedicle screws (PS) in a mono- or bicortical position in the atlas is a typical treatment. The bone microstructure and positioning of the screw trajectories appear to be of significant relevance for stability. Purpose: The aim of this study was a comparative analysis of the mechanical durability of screw fixation concerning microstructural characteristics of the trajectories of LMS and PS in mono- and bicortical position. Methods: Human C1 from geriatric body donors (n = 28; 50% female, age 80.8 ± 13.9 years) were collected and characterized based on their bone microstructure. Additionally, the mechanical stability of LMS and PS fixation in mono- and bicortical positioning was tested by mechanical loading. High-resolution quantitative computed tomography was used to analyze the bone microstructure of cylinders corresponding to the trajectories of PS and LMS in mono- and bicortical locations in each C1. After instrumentation with both screw types and types of fixation, the mechanical stability was tested by increased cyclic loading in cranio-caudal direction. Results: Trajectories of PS presented with more bone volume and a higher contact length to cortical bone. Simultaneously, a higher number of cycles and a higher maximum force was needed to loosen PS compared to LMS, while the loose by torque at the experiment end was still greater in PS. Differences between mono- and bicortical positioning of PS and LMS have only been observed in the initial stiffness of screws. When comparing microstructural and mechanical properties, the cortical contact length and bone volume in screw trajectories were strongest associated with a high loose and cycle count. Conclusions: This study suggests that mono- and bicortical positioning of PS is similarly efficient in creating a stable basis for screw fixation in the atlas. While PS are superior to LMS, the contact with cortical bone is of major relevance for a stable foundation. [ABSTRACT FROM AUTHOR]

Objective: Combining oblique lumbar interbody fusion (OLIF) with posterior pedicle screw fixation (PPSF) has been proposed to reduce cage subsidence, especially in osteoporotic spines. Recently, anterolateral screw-rod fixation has gained interest as it allows direct pathology observation and avoids a posterior approach. However, controversies exist between anterolateral screw fixation systems and traditional PPSF due to variations in osteoporotic vertebral mineral density, screw fixation positions, and fixation methods (bicortical vs. unicortical). This study aimed to investigate the biomechanical impact of fixation position and method in osteoporotic spine. Methods: Seventy-two fresh‑frozen porcine vertebrae (L1–6) were decalcified using 0.5 M EDTA and divided into two groups based on fixation method: bicortical or unicortical. Six groups for each method were created according to the screw position in the lateral vertebral body, with six specimens in each group: anterior, central, and posterior in the middle body and para-endplate regions. Correlations among screw position, fixation method and axial pullout strength were analyzed. Results: A 4-week decalcification process, bone mineral density in the porcine vertebrae decreased to approximately 48% (p < 0.05) of the original value, categorizing them as osteoporotic. Bicortical fixation showed significantly greater pullout forces than unicortical fixation, with differences ranging from 82 to 273%. Notably, central or posterior screws outperformed anterior screws in pullout strength. Conclusion: Bicortical fixation exhibited significantly greater pullout forces than unicortical fixation. We suggest positioning screws in the central or posterior region of the middle body with bicortical fixation in osteoporotic vertebrae. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to evaluate the accuracy and safety of C1 lateral mass and upper cervical pedicle screw placement assisted by the TiRobot II system. Methods: Ten patients who underwent cervical spine surgery assisted by the TiRobot II system were included. Screw accuracy was assessed using the Gertzbein-Robbins scale and by comparing the final screw positions with pre-planned trajectories. Deviations in screw tip, tail, and angle were recorded. Clinical data, including symptoms, surgical outcomes, and postoperative follow-up, were collected. Neurological improvement was evaluated using pre- and post-operative mJOA scores, with recovery rates calculated by Hirabayashi's method to assess outcomes 3 months after surgery. Results: A total of 30 screws were placed in 10 patients. All screws (30/30) were within the clinically acceptable range, with 93.33% (28 screws) classified as Grade A and 6.67% (2 screws) as Grade B. In the sagittal plane, the average tip deviation was 1.82 ± 0.79 mm, tail deviation 1.64 ± 0.60 mm, and angular deviation 1.92 ± 1.39°. In the axial plane, tip deviation was 1.96 ± 0.87 mm, tail deviation 1.92 ± 0.65 mm, and angular deviation 2.01 ± 1.07°. The average surgery time was 318.80 ± 66.07 min, with a mean EBL of 205.00 ± 55.03 mL. Postoperative mJOA scores significantly improved from 8.10 ± 1.97 to 12.60 ± 1.78 (p < 0.05), with a 52 ± 14% recovery rate. All patients showed significant symptom improvement. Conclusion: The TiRobot II system demonstrates the capability to precisely execute pre-planned trajectories and improves the accuracy and safety of C1 lateral mass and upper cervical screw placement. [ABSTRACT FROM AUTHOR]

Simple Summary: Degenerative lumbosacral stenosis (DLSS) can occur in small dogs for several reasons. Most 3D-printed guides used for spinal surgery in veterinary medicine are conventional guides. In this study, we used screw-guiding techniques to insert pedicle screws to minimize screw wobbling that may occur during screw insertion. We compared the accuracy of this technique with that of a conventional guide. The results showed that the screws placed using the screw-guiding technique demonstrated higher accuracy than those placed using the conventional guide. A 3D-printed guide is an effective method for accurately placing pedicle screws in dog vertebrae. While a conventional drill guide allows precise pilot hole formation, it can lead to potential screw wobbling during insertion. In this study, we applied a technique that assists with both drilling and screw insertion, and we compared the accuracy of screw placement using this approach with that achieved by the conventional drill guide. The screws were divided into three groups: Group A (drill guide), Group B (cannulated guide), and Group C (screw guide). The accuracy of screw placement was assessed by comparing preoperative and postoperative CT images. Group A exhibited the largest angular deviation. Group C exhibited significantly smaller deviations in entry point, exit point, angle α, and angular deviation than Group A. In Group B, only the exit-point deviation was significantly smaller than that in Group A. Furthermore, the angular deviation in Group C was significantly smaller than that in Group B. In conclusion, 3D-printed screw-guiding techniques improved the accuracy of pedicle screw placement, with screw guides outperforming cannulated guides, making them a viable option for small breed dogs. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective The pedicle screw insertion technique has evolved significantly, and despite the challenges of precise placement, advancements like AR‐based surgical navigation systems now offer enhanced accuracy and safety in spinal surgery by integrating real‐time, high‐resolution imaging with virtual models to aid surgeons. This study aims to evaluate the differences in accuracy between novel AR‐guided pedicle screw insertion and conventional surgery techniques. Methods A randomized controlled trial was conducted from March 2019 to December 2023 to compare the efficacy of AR‐guided pedicle screw fixation with conventional freehand surgery using CT guidance. The study included 150 patients, aged 18–75, with 75 patients in each group. The total number of pedicle screws planned for the clinical trial placement was 351 and 348 in the experimental and control groups. The safety and efficacy of the procedures were evaluated by assessing screw placement accuracy and complication rates. Results In the full analysis set (FAS) analysis, the difference in the excellent and good rates of screw placement (experimental group − control group) and 95% confidence interval was 6.3% [3.0%–9.8%], with a p value of 0.0003 for the superiority test. In the FAS sensitivity analysis, the success rate was 98.0% (344 out of 351) in the experimental group and 91.7% (319 out of 348) in the control group, with a difference and 95% confidence interval of 6.3% [2.9% and 9.8%, respectively]. In the per‐protocol set (PPS) analysis, the difference in the excellent and good rates of screw placement between the experimental and control groups, and the 95% confidence interval was 6.4% [3.3%–9.5%], with a p value of 0.0001 for the superiority test. In the actual treatment set (ATS) analysis, the excellent and good rates of screw placement were 99.1% in the experimental group and 91.7% in the control group. The difference in the excellent and good rates of screw placement (experimental group − control group) and 95% confidence interval was 7.3% [4.1%–10.6%], with a p value of

BACKGROUND: Facet joint osteoarthritis is acknowledged as a significant contributor to lower back pain in the geriatric population. The advent of an innovative spinal facet joint fusion device presents a therapeutic option for intervening during the initial stages of facet joint osteoarthritis, and significantly reduces the incidence of a series of complications caused by poor early conservative treatment and late surgical treatment. However, its effect on the biomechanics of the lumbar spine is unknown. OBJECTIVE: To investigate the biomechanical disparities between the novel lumbar zygapophyseal joint fusion device and traditional fusion devices. METHODS: A comprehensive three-dimensional finite element model of the L3-S1 lumbar spine was established and validated. Based on this intact model, three groups of surgical models were constructed: a bilateral pedicle screw fixation model, a bilateral novel facet joint fusion fixation model, and a bilateral facet screw fixation model, with the surgical segment designated as L4-5. Under a load of 500 N, a torque of 7.5 Nm was applied to all lumbar models to calculate the range of motion, displacement values, and intervertebral disc stress values at the L4-5 segment; stress values at the L3-4 and L5-S1 segments were also measured. RESULTS AND CONCLUSION: (1) Compared with the intact model, the range of motion at the L4-5 segment was reduced in all surgical models. (2) The novel device exhibited the smallest range of motion at the L4-5 segment under left and right rotational conditions; the greatest range of motion at the L4-5 segment under extension conditions; and a greater range of motion under other conditions than the bilateral pedicle screw fixation model. (3) The novel device demonstrated the smallest displacement values at the L4-5 segment under left and right rotational conditions; under other conditions, the displacement values at the L4-5 segment were greater than those in the bilateral pedicle screw fixation model. (4) In terms of stress distribution at the L4-5 segment, the novel device consistently exhibited the smallest values across all conditions. (5) For the L3-4 segment, the novel device showed the greatest stress values under extension and left and right rotational conditions, while under other conditions, the values were lower than those in the bilateral pedicle screw fixation model. (6) Compared with pedicle screw fixation, the novel device produced smaller stress values at the L5-S1 segment. (7) This study indicates that, compared with pedicle screw fixation, the novel device impacts the biomechanics of the lumbar spine by fusing the facet joints. It provides stability while preserving the range of motion at the surgical segment and reduces stress on the intervertebral discs of the surgical and adjacent segments, thereby potentially delaying disc degeneration. This suggests that the novel device can achieve biomechanical effects similar to those of pedicle screw fixation in theory. [ABSTRACT FROM AUTHOR]

Abstract Aim To investigate the safety and accuracy of robot-assisted pedicle screw placement in adolescent idiopathic scoliosis (AIS) surgery. Methods PubMed, Medline, Embase, Cochrane Library, Web of Science, CNKI, and EMCC databases were searched for studies utilizing the clinical data of adolescent idiopathic scoliosis patients (robot-assisted and fluoroscopy-assisted group) who underwent posterior pedicle screw fixation to collect preoperative, postoperative and follow-up indexes and imaging parameters, including screw implantation accuracy, the number of intraoperative fluoroscopy times, amount of bleeding, operation time, postoperative VAS score and postoperative Cobb angle. Results Six studies were included in this meta-analysis, including 154 patients in the intervention group and 171 patients in the control group. Our results showed that screw implantation accuracy (WMD 1.07, 95% CI (1.01,1.14), P = 0.03) was higher than that in the control group. The number of intraoperative fluoroscopy times (WMD -6.11, 95% CI (-9.60, -2.62), P = 0.0006) and operation time (WMD 31.52, 95% CI (5.70,57.35), P = 0.02) in the robot group were less, and the differences were statistically significant. Intraoperative blood (WMD -59.05, 95% CI (-212.81,94.70), P = 0.45), postoperative VAS score (WMD -0.07, 95% CI (-0.24,0.11), P = 0.46), preoperative Cobb angle (WMD 0.79, 95% CI (-1.12,2.69), P = 0.42) (Fig. 7), postoperative Cobb angle (WMD -0.25, 95% CI (-1.12,0.62), P = 0.57) (Fig. 8) had no statistical significance in the robot group compared with control group. Conclusion The robot navigation system can improve screw implantation accuracy and reduce the operation time and radiation exposure during the operation.

Abstract Background Manual placement of cervical pedicle screws is risky, and robot-assisted placement of atlantoaxial pedicle screws has not been reported. Case report We describe a 74-year-old female patient with atlantoaxial fracture and dislocation combined with spinal cord injury caused by a car accident. The left lower limb muscle strength was grade 0, the right upper limb muscle strength was grade 1, and the right lower limb muscle strength was grade 2. Loss of sensation below the clavicle level, decreased superficial sensation in the extremities, loss of deep sensation in the left lower extremity, and incontinence were observed. We successfully placed atlas pedicle screws with the assistance of the Mazor X robot. One week after the operation, radiological imaging revealed that the reduction effect was good, the placement of the pedicle screws was satisfactory, the left upper limb and left lower limb muscle strength was level 2, the right upper limb and the muscle strength of the right lower limb were grade 3, and the sensory function was partially restored. No complications related to screw placement were found at the 3-month postoperative follow-up. Conclusions Mazor X robot-assisted descending pedicle screw fixation of the atlas is feasible and safe.

The increasing frequency of cervical and lumbar spine disorders, driven by aging and evolving lifestyles, has led to a rise in spinal surgeries using pedicle screws. Robotic spinal surgery systems have emerged as a promising innovation, offering enhanced accuracy in screw placement and improved surgical outcomes. We focused on literature of this field from the past 5 years, and a comprehensive literature search was performed using PubMed and Google Scholar. Robotic spinal surgery systems have significantly impacted spinal procedures by improving pedicle screw placement accuracy and supporting various techniques. These systems facilitate personalized, minimally invasive, and low‐radiation interventions, leading to greater precision, reduced patient risk, and decreased radiation exposure. Despite advantages, challenges such as high costs and a steep learning curve remain. Ongoing advancements are expected to further enhance these systems' role in spinal surgery.

Study Design Biomechanical study. Purpose To investigate the mechanical characteristics of bone models created from medical images. Overview of Literature Recent advancements in three-dimensional (3D) printing technology have affected its application in surgery. However, a notable gap exists in the analyses of how patient’s dimorphism and variations in vertebral body anatomy influence the maximum insertional torque (MIT) and pullout strength (POS) of pedicle screws (PS) in osteoporotic vertebral bone models derived from medical images. Methods Male and female patients with computed tomography data were selected. Dimensions of the first thoracic (T1), fourth lumbar (L4), and fifth lumbar (L5) vertebrae were measured, and bone models consisting of the cancellous and cortical bones made from polyurethane foam were created. PS with diameters of 4.5 mm, 5.5 mm, and 6.5 mm were used. T1 PS were 25 mm long, and L4 and L5 PS were 40 mm long. The bone models were secured with cement, and the MIT was measured using a calibrated torque wrench. After MIT testing, the PS head was attached to the machine’s crosshead. POS was then calculated at a crosshead speed of 5 mm/min until failure. Results The L4 and L5 were notably larger in female bone models, whereas the T1 vertebra was larger in male bone models. Consequently, the MIT and POS for L4 and L5 were higher in female bone models across all PS diameters than in male bone models. Conversely, the MIT for T1 was higher in male bone models across all PS; however, no significant differences were observed in the POS values for T1 between sexes. Conclusions The mechanical properties of the proposed bone models can vary based on the vertebral structure and size. For accurate 3D surgical and mechanical simulations in the creation of custom-made medical devices, bone models must be constructed from patient-specific medical images.

Objective For degenerative diseases accompanied by cervical malalignment, the starting and ending points of fixation for better cervical sagittal alignment and clinical results are not as clear as the thoracolumbar region. In this study we aimed to compare the effects of posterior subaxial cervical fixation (PSCF), posterior cervical fixation extending to the upper thoracic region and posterior upper cervical fixation extending to the upper thoracic region on cervical sagittal alignment. Methods Sixty‐three patients who underwent posterior cervical and cervical‐up thoracic fixation were retrospectively analyzed in a comparative study. The procedures that we performed from May 2019 to March 2022 on these 63 patients were: (1) C3‐C6 group—posterior subaxial cervical fixation; (2) Subaxial‐T2 group—posterior subaxial cervicothoracic fixation (PSCTF); (3) C2‐T2 upper thoracic posterior fixation group. The C3‐C6 group had 27 patients, Subaxial‐T2 group had 24, and C2‐T2 group had 12. We determined the minimum follow‐up period as 12 months. C0‐2, C2‐7 lordosis angle, sagittal vertical axis (SVA), C2 slope, C7 slope, T1 slope, cervical slope, neck slope, and thoracic inlet angle (TIA) measurements were made in three patient groups. Comparatively, cervical sagittal alignment was evaluated. Result In the C2‐T2 group, a significant increase in C2‐C7 lordosis, decrease in C2 slope, and increase in TS‐CL were observed. Significant C2‐C7 lordosis decrease, C2 slope increase, and TS‐CL decrease were observed in the C3‐C6 group. A significant increase in C2‐C7 lordosis and a decrease in C2 slope were observed in the subaxial‐T2 group. No significant change was observed in the TS‐CL angle. Conclusion In cervical degenerative disorders accompanied by cervical malalignment, we recommend the C2‐T2 fixation method, which provides the desired C2‐C7 lordosis, SVA within the normal range, and the best Neck Disability Index results.

Abstract Background To study the risk factors associated with misplacement of freehand pedicle screws through a posterior approach for degenerative scoliosis. Methods A total of 204 patients who underwent posterior pedicle screw-rod system surgery for degenerative scoliosis in our hospital from December 2020 to December 2023 were retrospectively analyzed. Patient demographics, radiographic accuracy, and surgery-related information were recorded. Results A total of 204 patients were included. A total of 2496 screws were placed. 2373 (95.07%) were in good position. Misplacement screws were 123 (4.93%). None of the patients had postoperative spinal nerve symptoms due to screw malposition. The misplacement rate of thoracic (T10-T12) pedicle screws was 11.11% (60/540). Misplacement of pedicle screws in the lumbar spine (L1-L5) was 3.22% (63/1956). Age, gender, surgeon, and operation time had no significant effect on misplacement of pedicle screws (P>0.05). Body mass index, Hu value, number of screw segments, Cobb angle, vertebral rotation, and spinal canal morphology had some correlation with pedicle screw misplacement. Among them, BMI, Hu value, number of screw segments, Cobb angle, and vertebral rotation grade were independent risk factors for PS misplacement (P

BACKGROUND: Atlantoaxial dislocation, because of its high difficulty and high risk of surgery, has been regarded as the “surgical restricted area” by the international orthopedic community. However, with the rapid development of intelligent digitization in orthopedics, robot-assisted navigation screw placement technology has been widely used in clinical practice, which significantly reduces the difficulty and risk of surgery and improves the safety of surgery. However, there are few reports on the application of this technique in the treatment of atlantoaxial dislocation. OBJECTIVE: To explore the application value of robot-assisted pedicle screw internal fixation in the treatment of atlantoaxial dislocation. METHODS: The medical records of five patients with atlantoaxial dislocation treated with C1-C2 pedicle screw fixation under robot-assisted navigation in Zhuhai Hospital of Guangdong Provincial Hospital of Chinese Medicine from October 2021 to July 2022 were retrospectively analyzed. Operation time, length of neck incision, blood loss, postoperative drainage volume, and length of hospital stay were recorded. Attention should be paid to cerebrospinal fluid leakage, vertebral artery injury, nerve injury, operative area infection and other complications. The visual analog scale score of neck pain, the spinal cord injury grade of the American Spinal Injury Association, the cervical spine score of the Japanese Orthopaedic Association, and the imaging indicators were collected before surgery and at the last follow-up. Screw placement accuracy was assessed. RESULTS AND CONCLUSION: (1) Five patients were successfully completed surgery, without vascular, nerve injury or other complications, and were followed up for 12-20 months. (2) A total of 20 cervical pedicle screws were placed in 5 patients, including 9 type A screws, 10 type B screws, and 1 type C screw. The accuracy of screw placement was 95%. (3) At the last follow-up, the visual analog scale score was (0.80±0.71) points, which was significantly lower than that before operation (4.00±2.83) points; the Japanese Orthopaedic Association score was (14.80±0.84) points, which was significantly higher than that before operation (8.00±0.71) points. Anterior atlantodental interval decreased from (7.86±3.25) mm to (2.82±0.93) mm; space available of the spinal cord increased from (6.74±1.99) mm to (12.10±3.51) mm; cervicomedullary angle increased from (133.32±13.55)° to (153.44±9.53)°; clivus-canal angle increased from (128.02±9.92)° to (143.25±12.99)°. The results of the last follow-up indexes were improved compared with those before operation, and the differences were significant (all P < 0.05). (4) Postoperative imaging follow-up showed that all patients had bone fusion in the bone graft area, and no internal fixation loosening, fracture or pull-out occurred. (5) This method can avoid relying on the doctor’s experience and hand feeling, ensure the accuracy of upper cervical screw placement, reduce the risk of surgery, and obtain satisfactory results in mid-term follow-up. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the impact of the Landmark Crater (LC) method on pedicle perforation rates in robot-guided surgery for pediatric scoliosis for each pedicle diameter. Methods: Seventy-six scoliosis patients underwent robot-assisted posterior spinal fusion. The cohort consisted of 19 male and 57 female patients, with a mean ± standard deviation age of 17.5 ± 7.7 years and a preoperative Cobb angle of 57.0 ± 18.5°. The LC method is a method in which craters that serves as a landmark are created in advance at the planned PS insertion site of all pedicles within the intraoperative CT imaging area. The patients were divided into the LC group, in which PS insertion was performed using the LC method, and the control group using the conventional PS insertion method. Overall and pedicle perforation rates for each pedicle outer diameter were compared between the groups by Fisher's exact test. Results: The LC group exhibited a significantly lower pedicle major perforation rate than did the control group (2.7% vs. 6.2%, P = 0.001). The perforation rates in pedicles with a pedicle outer diameter > 6 mm, 4–6 mm, 2–4 mm, and < 2 mm were 0.61%, 1.6%, 5.1%, and 21%, in the LC group and 0.75%, 4.1%, 12%, and 50% in the control group, respectively. Conclusion: In robot-assisted surgery for pediatric scoliosis, the LC method enabled significantly lower pedicle perforation rates over the conventional method. Both the LC and conventional methods exhibited higher perforation rates for smaller pedicle diameters. [ABSTRACT FROM AUTHOR]

Objective: We aimed to investigate the incidence of delayed-onset neurological deficits (DONDs), DOND-related reoperation rates following adult spinal deformity (ASD) surgery, and efficacy of transverse process hooks (TPHs) at the uppermost instrumented vertebra (UIV) compared to pedicle screws (PSs). Methods: We included 90 consecutive patients who underwent instrumented fusion from the sacrum to the distal thoracic spine for ASD, with a minimum follow-up of 24 months. Clinical and radiological outcomes were compared between 33 patients in the TPH group and 57 patients in the PS group, using the Scoliosis Research Society-22 Outcomes questionnaire (SRS-22), Medical Outcomes Study Questionnaire Short-Form 36 (SF-36), and various spinal sagittal parameters. Results: While absent in the TPH group, myelopathy occurred in 15.8% of the PS group, wherein 15 patients underwent reoperation. The change in the proximal junctional angle, from the pre- to postoperative assessment, was lower in the TPH group than in the PS group (0.2 vs. 6.6, p=0.002). Postoperative facet degeneration in the PS group progressed more significantly than in the TPH group (0.5 vs. 0.1, p=0.002). Surgical outcomes were comparable for both groups, except for the back visual analogue scale (3.5 vs. 4.1, p=0.010) and SRS-22 domains, including pain and satisfaction (3.3 vs. 2.9, p=0.033; 3.7 vs. 3.3, p=0.041). No intergroup difference was observed in SF-36. Conclusion: Using TPHs at the UIV level can prevent DOND, and thereby prevent postoperative myelopathy that necessitates reoperation; thus, TPHs is preferable over PSs in ASD surgery. [ABSTRACT FROM AUTHOR]

The accurate and safe positioning of cervical pedicle screws is crucial. While augmented reality (AR) use in spine surgery has previously demonstrated clinical utility in the thoracolumbar spine, its technical feasibility in the cervical spine remains less explored. The objective of this study was to assess the precision and safety of AR-assisted pedicle screw placement in the cervical spine. In this experimental study, 5 cadaveric cervical spine models were instrumented from C3 to C7 by 5 different spine surgeons. The navigation accuracy and clinical screw accuracy were evaluated. Postprocedural CT scans were evaluated for clinical accuracy by 2 independent neuroradiologists using the Gertzbein-Robbins scale. Technical precision was assessed by calculating the angular trajectory (°) and linear screw tip (mm) deviations in the axial and sagittal planes from the virtual pedicle screw position as recorded by the AR-guided platform during the procedure compared to the actual pedicle screw position derived from postprocedural imaging. A total of forty-one pedicle screws were placed in 5 cervical cadavers, with each of the 5 surgeons navigating at least 7 screws. Gertzbein-Robbins grade of A or B was achieved in 100% of cases. The mean values for tip and trajectory errors in the axial and sagittal planes between the virtual versus actual position of the screws was less than 3 mm and 30°, respectively (p<.05). None of the cervical screws violated the cortex by more than 2 mm or displaced neurovascular structures. AR-assisted cervical pedicle screw placement in cadavers demonstrated clinical accuracy comparable to existing literature values for image-guided navigation methods for the cervical spine. This study provides technical and clinical accuracy data that supports clinical trialing of AR-assisted subaxial cervical pedicle screw placement. [ABSTRACT FROM AUTHOR]

Background: Robotic platforms have increased in sophistication for pedicle screw placement. Here, we review our institutional experience using ExcelsiusGPS to assess the accuracy rate of pedicle screw placement throughout the spine and characterize predictors of placement inaccuracy. Study Design: Retrospective cohort study. Methods: Patients from 2017 to 2022 undergoing spinal fusion surgery with ExelsiusGPS-assisted screw implantation at a single tertiary center were retrospectively identified. Patient demographics, preoperative symptoms, and operative details were collected. Postoperative computed tomography was used to classify screw placement accuracy according to the Gertzbein and Robbins scale (GRS). A stepwise multivariable ordered logistic regression analysis determined independent risk factors for clinically inaccurate screws (GRS C/D/E). Results: One hundred and seventeen patients were included. Mean age was 60.6 ± 13.2 years, with 57% men, 72% white, and mean body mass index of 29.9 ± 6.4 kg/m2. Seven hundred and twenty-eight screws were placed, predominantly in the thoracic (29.5%) and lumbar (52.6%) regions. Accuracy classification indicated 670 GRS A, 31 GRS B, 22 GRS C, 4 GRS D, and 1 GRS E screws. The clinically acceptable screw placement rate (GRS A/B) was 96%. Male gender (odds ratio [OR]: 2.12, P = 0.03), revision surgery (OR: 2.43, P = 0.02), and thoracic level screw insertion (OR: 2.33, P = 0.01) were independently associated with inaccurate screw placement and explained 8.7% of the variability seen. Of the 728 screws placed, 3 required revision after postoperative imaging revealed loosening or pedicle breach. Conclusion: ExcelsiusGPS-assisted screw insertion has high placement accuracy and low revision rates. Identification of predictors of inaccuracy illustrates that similar variables, such as placement in the thoracic spine and revision surgery status, apply to both freehand and robotic screw placement. Clinical Relevance: Robotic spine surgery is an accurate, reliable tool that can improve patient outcomes. Factors like male gender, thoracic screw placement, and revision surgery status are associated with lower screw placement accuracy, and these factors should inform surgical decision-making when using robotic assistance. [ABSTRACT FROM AUTHOR]

Aim: To investigate the safety and accuracy of robot-assisted pedicle screw placement in adolescent idiopathic scoliosis (AIS) surgery. Methods: PubMed, Medline, Embase, Cochrane Library, Web of Science, CNKI, and EMCC databases were searched for studies utilizing the clinical data of adolescent idiopathic scoliosis patients (robot-assisted and fluoroscopy-assisted group) who underwent posterior pedicle screw fixation to collect preoperative, postoperative and follow-up indexes and imaging parameters, including screw implantation accuracy, the number of intraoperative fluoroscopy times, amount of bleeding, operation time, postoperative VAS score and postoperative Cobb angle. Results: Six studies were included in this meta-analysis, including 154 patients in the intervention group and 171 patients in the control group. Our results showed that screw implantation accuracy (WMD 1.07, 95% CI (1.01,1.14), P = 0.03) was higher than that in the control group. The number of intraoperative fluoroscopy times (WMD -6.11, 95% CI (-9.60, -2.62), P = 0.0006) and operation time (WMD 31.52, 95% CI (5.70,57.35), P = 0.02) in the robot group were less, and the differences were statistically significant. Intraoperative blood (WMD -59.05, 95% CI (-212.81,94.70), P = 0.45), postoperative VAS score (WMD -0.07, 95% CI (-0.24,0.11), P = 0.46), preoperative Cobb angle (WMD 0.79, 95% CI (-1.12,2.69), P = 0.42) (Fig. 7), postoperative Cobb angle (WMD -0.25, 95% CI (-1.12,0.62), P = 0.57) (Fig. 8) had no statistical significance in the robot group compared with control group. Conclusion: The robot navigation system can improve screw implantation accuracy and reduce the operation time and radiation exposure during the operation. [ABSTRACT FROM AUTHOR]

Background and Objectives: Spine surgery has undergone significant advancements, particularly with regard to robotic systems that enhance surgical techniques and improve patient outcomes. As these technologies become increasingly integrated into surgical practice, it is essential to evaluate their added value and cost savings. Hence, this study compared robot-assisted and navigation-based spine surgery, focusing on surgical efficiency. Materials and Methods: We conducted a single-center, retrospective cohort study of patients undergoing single- and double-level transforaminal lumbar interbody fusion (TLIF) and oblique lumbar interbody fusion (OLIF) surgeries. Patients were divided into two groups: those who had robot-assisted and navigation-based surgeries, stratified by surgery type (TLIF or OLIF) and fusion levels (one or two). A comparative analysis of factors related to surgical efficiency, including operative duration, blood loss, and length of hospital stay, was conducted. Results: Our results showed a statistically significant reduction in operative duration for robot-assisted one- and two-level OLIF cases, with average time savings of 50 and 62 min, respectively, compared to navigation-based surgery. These time savings translated to an estimated cost reduction of SGD 1500 for the hospital for each patient for a two-level OLIF procedure and could be higher as the number of operated levels increase. Conclusions: These results indicated that robot-assisted spine surgery offers superior surgical efficiency and cost savings, particularly with increased numbers of surgical levels. As robotic technologies evolve, their integration into spine surgery is justified, promising improved patient outcomes and cost-effectiveness. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bone grafting is one of the important steps in the treatment of thoracolumbar burst fractures. Because the fracture involves the spinal canal or is accompanied by spinal cord nerve damage, severe fracture bleeding and other factors, minimally invasive bone grafting for thoracolumbar burst fractures is restricted. At present, the minimally invasive treatment of thoracolumbar burst fractures is limited to percutaneous screw fixation under the tunnel. Minimally invasive percutaneous bone grafting of injured vertebrae is rarely reported, and percutaneous precise bone grafting under the endplate has not yet been reported. OBJECTIVE: To investigate the clinical effect of subcutaneous endplate bone graft support reduction combined with percutaneous pedicle screw short-segment fixation in the treatment of A3+B2 thoracolumbar burst fractures. METHODS: From June 2017 to December 2021, 90 patients with A3+B2 type asymptomatic thoracolumbar burst fracture were randomly divided into 3 groups according to admission time. In group A, 33 patients received the bone graft funnel accurately placed through the pedicle channel by percutaneous puncture under C-arm fluoroscopy, bone graft support reduction under the fracture endplate, percutaneous pedicle screw fixation. In group B, 30 patients received multifissure intermuscular approach through pedicle bone graft support reduction combined with pedicle screw fixation. In group C, 27 patients received percutaneous pedicle screw short-segment fixation under postural reduction. All patients were followed up for at least 18 months after surgery. The clinical data of the three groups, including preoperative, postoperative and last follow-up Cobb angle, anterior edge height ratio and visual analog scale pain score, were compared and analyzed. RESULTS AND CONCLUSION: (1) There were no significant differences in age, sex, injury segment and causative factors among the three groups (P > 0.05). (2) All patients at follow-up had no neurological impairment, no obvious lumbar posterior deformity or intractable low back pain. (3) The operation time of group C was less than that of group A and group B (P < 0.05). Intraoperative blood loss was less in group A and group C than in group B (P < 0.05). (4) There were no significant differences in the anterior edge height ratio and Cobb angle among the three groups (P > 0.05). Postoperative data in groups A and B were better than that in group C. At last follow-up, group A and group B outperformed group C (P < 0.05). The height and Cobb angle of the vertebral body lost in the three groups were smaller in groups A and B than those in group C (P < 0.05). (5) Visual analog scale pain score was better in groups A and C than that in group B after surgery (P < 0.05). There was no significant difference in visual analog scale pain score among the three groups at last follow-up (P > 0.05). (6) In group C, there was one case of loose internal fixation and displacement in 1 month after surgery, and the vertebral height was lost again with back pain, and after strict bed rest for 6 weeks, the vertebral height loss was not aggravated, the pain was relieved, and the internal fixation was removed after 1 year, and the height loss at the last follow-up was not aggravated. There were no cases of failure of internal fixation in groups A and B. (7) It is indicated that subcutaneous endplate bone graft support reduction combined with percutaneous pedicle screw short-segment fixation in the treatment of A3+B2 thoracolumbar burst fracture has the advantages of less trauma, less bleeding and light postoperative pain symptoms, and the effect of injury vertebral reduction and height maintenance is the same as the reduction through pedicle bone grafting support and short segment fixation with pedicle screws through the multifidus space approach. [ABSTRACT FROM AUTHOR]

Background: With the increasing number of surgeries utilizing spinal instrumentation, three-dimensional surgical navigation aims to improve the accuracy of implant placement. However, its widespread clinical adaption has been hindered by factors such as high radiation exposure and interference with standard surgical workflows. Methods: X23D is a novel AI-based fluoroscopy reconstruction technique that generates a 3D anatomical model of the spine from only four fluoroscopy images. Based on this technology, we developed a prototype for the surgical navigation of pedicle screws placement of the lumbar spine, visualizing the 3D-reconstructed spine anatomy and the surgical drill position in real-time. An ex-vivo study was conducted to compare the accuracy of the X23D-based navigation approach with fluoroscopy-aided freehand instrumentation. Five board-certified surgeons placed pedicle screws on six human torsi within a realistic surgical environment. Breach rate, site and extent (Gertzbein-Robbins) were evaluated in postoperative CT scans, as well as execution time, radiation dose, and user experience. Specimens, operating side, and surgeon were randomised. Results: Forty-nine pedicle screws (n = 24 × 23D, n = 25 2D-fluoroscopy) were evaluated, with six breaches occurring in the control group, one of which was considered clinically significant (medial breach grade C). Five breaches with one clinically significant breach were observed in the X23D group. Breach rate, execution time for each lumbar level (X23D 167 s vs. control 156 s), radiation dose (X23D 33.26 mGy vs. control 49.5 mGy), and user experience did not reveal significant differences (p > 0.05) between the groups. Conclusions: Spinal navigation using the X23D-based approach shows promise and performs well in a realistic surgical ex-vivo setting. With further refinements, its accuracy is expected to match clinical-grade navigation systems while reducing radiation dose. [ABSTRACT FROM AUTHOR]

Background: Manual placement of cervical pedicle screws is risky, and robot-assisted placement of atlantoaxial pedicle screws has not been reported. Case report: We describe a 74-year-old female patient with atlantoaxial fracture and dislocation combined with spinal cord injury caused by a car accident. The left lower limb muscle strength was grade 0, the right upper limb muscle strength was grade 1, and the right lower limb muscle strength was grade 2. Loss of sensation below the clavicle level, decreased superficial sensation in the extremities, loss of deep sensation in the left lower extremity, and incontinence were observed. We successfully placed atlas pedicle screws with the assistance of the Mazor X robot. One week after the operation, radiological imaging revealed that the reduction effect was good, the placement of the pedicle screws was satisfactory, the left upper limb and left lower limb muscle strength was level 2, the right upper limb and the muscle strength of the right lower limb were grade 3, and the sensory function was partially restored. No complications related to screw placement were found at the 3-month postoperative follow-up. Conclusions: Mazor X robot-assisted descending pedicle screw fixation of the atlas is feasible and safe. [ABSTRACT FROM AUTHOR]

Objective. To examine the shape change of screw-rod constructs over time after short-segment lumbar interbody fusion and to clarify its relationship to clinical characteristics. Summary of Background Data. No study has focused on the shape change of screw-rod constructs after short-segment fusion and its clinical implications. Methods. One hundred eight patients who had single-level lumbar interbody fusion with pedicle screws and cages were enrolled. Three-dimensional (3D) images of screw-rod constructs were generated from baseline CT on the day after surgery and followup CT and were superposed on the right and left side, respectively, using the iterative closest point algorithm. The shape change was quantitatively assessed by computing the median distance between the 3D images, which was defined as the shape change value. Among the 5 time-course categories of follow-up CT (=1, 2-3, 4-6, 7-12, and =13 months), the shape change values were compared. The relationships between the shape change values and clinical characteristics, such as age, CT-derived vertebral bone mineral density, screw and rod materials, and postoperative interbody fusion status, cage subsidence, and screw loosening, were evaluated. Results. A total of 237 follow-up CTs were included (=1 [34 scans], 2-3 [33 scans], 4-6 [80 scans], 7-12 [48 scans], and = 13 months [42 scans]) because many patients underwent multiple follow-up CTs. There were significant differences in shape change values among the time-course categories (P<0.001 in Kruskal-Wallis test). Most shape changes occurred within 6 months postoperatively, with no significant changes observed at 7 months or more. There were no significant relationships between the shape change values and each clinical characteristic. Conclusions. The temporal shape changes of screw-rod constructs following short-segment lumbar interbody fusion progressed up to 6 months after surgery but not significantly thereafter. [ABSTRACT FROM AUTHOR]

Spinal fusion surgery is known to be an expensive intervention. Although innovative technologies in the field aim at improving operative efficiency and outcomes, total costs must be considered. The authors hope to elucidate any differences between robot-assisted (RA) and computed tomography navigation (CT-nav) or freehand fluoroscopy-guided (FFG) pedicle screw placement in relation to patient outcomes and cost-effectiveness in lumbar fusion surgery (LFS). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the authors performed a systematic review to identify studies comparing clinical outcomes between CT-nav or RA versus FFG in LFS patients. All included studies utilized bilateral pedicle screws. Statistical analysis was performed using R. Of the 1162 identified studies, 5 were included in the analysis. Direct evidence showed that RA decreased hospital length of stay when compared to FFG (mean difference [MD]: −2.67 days; 95% confidence interval [CI]: −4.25 to −1.08; P < 0.01). Indirect evidence showed that RA decreased operative time when compared to CT-nav (MD: −65.57 minutes; 95% CI: −127.7 to −3.44; P < 0.05). For estimated blood loss, direct evidence showed that RA was superior to FFG (MD: −120.62 mL; 95% CI: −206.39 to −34.86; P < 0.01). However, no significant difference was found between RA and CT-nav for estimated blood loss (MD: 14.88 mL; 95% CI: −105.54 to 135.3; P > 0.05). There were no other significant differences in Oswestry Disability Index, visual analog scale, or complication or reoperation rates between RA and FFG or CT-nav. This study shows that RA pedicle screw placement in LFS provides similar patient outcomes to CT-nav and FFG. Robot-assisted operations were found to give rise to cost savings via decreased length of stay when compared to both CT-nav and FFG techniques. Cost-savings of $4086–$4865/patient and $7317–$9654/patient could be achieved when utilizing RA over CT-nav and FFG, respectively. However, extra upfront and maintenance costs may impact full adoption of RA in LFS. [ABSTRACT FROM AUTHOR]

Purpose: To test equivalency of deep-learning 3D lumbar spine MRI with "CT-like" contrast to CT for virtual pedicle screw planning and geometric measurements in robotic-navigated spinal surgery. Methods: Between December 2021 and June 2022, 16 patients referred for spinal fusion and decompression surgery with pre-operative CT and 3D MRI were retrospectively assessed. Pedicle screws were virtually placed on lumbar (L1-L5) and sacral (S1) vertebrae by three spine surgeons, and metrics (lateral deviation, axial/sagittal angles) were collected. Vertebral body length/width (VL/VW) and pedicle height/width (PH/PW) were measured at L1-L5 by three radiologists. Analysis included equivalency testing using the 95% confidence interval (CI), a margin of ± 1 mm (± 2.08° for angles), and intra-class correlation coefficients (ICCs). Results: Across all vertebral levels, both combined and separately, equivalency between CT and MRI was proven for all pedicle screw metrics and geometric measurements, except for VL at L1 (mean difference: − 0.64 mm; [95%CI − 1.05, − 0.24]), L2 (− 0.65 mm; [95%CI − 1.11, − 0.20]), and L4 (− 0.78 mm; [95%CI − 1.11, − 0.46]). Inter- and intra-rater ICC for screw metrics across all vertebral levels combined ranged from 0.68 to 0.91 and 0.89–0.98 for CT, and from 0.62 to 0.92 and 0.81–0.97 for MRI, respectively. Inter- and intra-rater ICC for geometric measurements ranged from 0.60 to 0.95 and 0.84–0.97 for CT, and 0.61–0.95 and 0.93–0.98 for MRI, respectively. Conclusion: Deep-learning 3D MRI facilitates equivalent virtual pedicle screw placements and geometric assessments for most lumbar vertebrae, with the exception of vertebral body length at L1, L2, and L4, compared to CT for pre-operative planning in patients considered for robotic-navigated spine surgery. [ABSTRACT FROM AUTHOR]

The increasing frequency of cervical and lumbar spine disorders, driven by aging and evolving lifestyles, has led to a rise in spinal surgeries using pedicle screws. Robotic spinal surgery systems have emerged as a promising innovation, offering enhanced accuracy in screw placement and improved surgical outcomes. We focused on literature of this field from the past 5 years, and a comprehensive literature search was performed using PubMed and Google Scholar. Robotic spinal surgery systems have significantly impacted spinal procedures by improving pedicle screw placement accuracy and supporting various techniques. These systems facilitate personalized, minimally invasive, and low‐radiation interventions, leading to greater precision, reduced patient risk, and decreased radiation exposure. Despite advantages, challenges such as high costs and a steep learning curve remain. Ongoing advancements are expected to further enhance these systems' role in spinal surgery. [ABSTRACT FROM AUTHOR]

To investigate the biomechanical properties of pedicle screw reinsertion along the same trajectory in a previously validated synthetic bone model. Twenty identical acrylonitrile butadiene styrene models of lumbar vertebrae were three-dimensional-printed. Screws were placed in the standard fashion into each pedicle. Models were separated into 2 equal groups, control and experimental. Experimental group screws were completely removed from their testing block and reinserted once. All screws in both groups were then forcibly removed. Continuous torque monitoring was collected on screw insertion torque (IT), removal torque, and reinsertion torque. Pullout strength (PO), screw stiffness (STI), and strain energy (STR) were calculated. There was no significant difference between control and experimental groups for PO (P = 0.26), STI (P = 0.55), STR (P = 0.50), or IT (P = 0.24). There was a significant decrease in reinsertion torque (54.5 N-cm ± 8.2 N-cm) from control IT (62.9 N-cm ± 8.4 N-cm, P = 0.045) and experimental IT (67.5 N-cm ± 7.6 N-cm, P = 0.0026). Strong correlations (Pearson's r > 0.80) were seen between control IT against STR and PO, between each of the experimental torque measurements, and between experimental PO and STI. Despite a significant decrease in insertion torque, there is no significant loss of pedicle screw performance when a screw is removed and reinserted along the same trajectory. [ABSTRACT FROM AUTHOR]

Screw loosening is a common complication of pedicle screw internal fixation surgery. This study aimed to investigate whether the application of a porous scaffold structure can increase the contact area between screws and bone tissue by comparing the bone ingrowth and screw-bone interface of porous scaffold core pedicle screws (PSCPSs) and hollow lateral hole pedicle screws (HLHPSs) in the lumbar spine of Bama pigs. Sixteen pedicle screws of both types were implanted into the bilateral pedicles of the L1–4 vertebrae of 2 Bama pigs. All Bama pigs were sacrificed and the lumbar spine was freed into individual vertebrae at 16 weeks postoperatively. After the vertebrae were made into screw-centered specimens, micro-computed tomography analysis and histological observation were performed to assess the screw-bone interface and bone growth around and within the screws. We found that the bone condition around PSCPSs and HLHPSs did not show significant differences on micro-computed tomography three-dimensional reconstruction images. CT transverse views showed different bone growth inside the 2 screws. In PSCPSs, bone tissue was seen to fill the internal pores and was evenly distributed around each strut. Inside HLHPSs, bone growth was confined to 1 side of the screw and did not fill the entire cavity. Osteometric analysis showed that bone volume fraction and trabecular number, the parameters representing bone mass, were higher in PSCPSs than in HLHPSs. These differences were not statistically significant (P > 0.05). Histological observations visualized that the osseointegration within PSCPSs was superior to that of HLHPSs, and the tight integration of bone tissue with the porous scaffold resulted in a larger screw-bone integration area in PSCPSs than in HLHPSs. Compared with HLHPSs, PSCPSs possessing a porous scaffold core could promote bone ingrowth and osseointegration, resulting in an effective enhancement of the combined area of the screw-bone interface. [ABSTRACT FROM AUTHOR]

To compare the stability of a corticopedicular posterior fixation (CPPF) device with traditional pedicle screws for decompression and fusion in adult degenerative lumbar spondylolisthesis. Finite element analysis (FEA) was used in a validated model of grade 1 L4–L5 spondylolisthesis to compare segmental stability after laminectomy alone, laminectomy with pedicle screw fixation, or laminectomy with CPPF device fixation. A 500-N follower load was applied to the model and different functional movements were simulated by applying a 7.5-Nm force in different directions. Outcomes included degrees of motion, tensile forces experienced in the CPPF device, and stresses in surrounding cortical bone. At maximum loading, laminectomy alone demonstrated a 1° increase in flexion range of motion, from 6.35° to 7.39°. Laminectomy with pedicle screw fixation and CPPF device fixation both reduced spinal segmental motion to ≤1° at maximum loading in all ranges of motion, including flexion (0.94° and 1.09°), extension (–0.85° and –1.08°), lateral bending (–0.56° and –0.96°), and torsion (0.63° and 0.91°), respectively. There was no significant difference in segmental stability between pedicle screw fixation and CPPF device fixation during maximum loading, with a difference of ≤0.4° in any range of motion. Tensile forces in the CPPF device remained ≤51% the ultimate load to failure (487 N) and stress in surrounding cortical bone remained ≤84% the ultimate stress of cortical bone (125.4 MPa) during maximum loading. CPFF fixation demonstrated similar segmental stability to traditional pedicle screw fixation whereas tensile forces and stress in surrounding cortical bone remained below the load to failure. [ABSTRACT FROM AUTHOR]

Robotic spine surgery, utilizing 3D imaging and robotic arms, has been shown to improve the accuracy of pedicle screw placement compared to conventional methods, although its superiority remains under debate. There are few studies evaluating the accuracy of 3D navigated versus robotic-guided screw placement across lumbar levels, addressing anatomical challenges to refine surgical strategies and patient safety. This study aims to investigate the pedicle screw placement accuracy between 3D navigation and robotic arm-guided systems across distinct lumbar levels. A retrospective review of a prospectively collected registry. Patients undergoing fusion surgery with pedicle screw placement in the prone position, using either via 3D image navigation only or robotic arm guidance. Radiographical screw accuracy was assessed by the postoperative computed tomography (CT) according to the Gertzbein-Robbins classification, particularly focused on accuracy at different lumbar levels. Accuracy of screw placement in the 3D navigation (Nav group) and robotic arm guidance (Robo group) was compared using Chi-squared test/Fisher's exact test with effect size measured by Cramer's V, both overall and at each specific lumbosacral spinal level. A total of 321 patients were included (Nav, 157; Robo, 189) and evaluated 1210 screws (Nav, 651; Robo 559). The Robo group demonstrated significantly higher overall accuracy (98.6 vs 93.9%; p<.001, V=0.25). This difference of no breach screw rate was signified the most at the L3 level (No breach screw: Robo 91.3 vs 57.8%, p<.001, V=0.35) followed by L4 (89.6 vs 64.7%, p<.001, V=0.28), and L5 (92.0 vs 74.5%, p<.001, V=0.22). However, screw accuracy at S1 was not significant between the groups (81.1 vs 72.0%, V=0.10). This study highlights the enhanced accuracy of robotic arm-guided systems compared to 3D navigation for pedicle screw placement in lumbar fusion surgeries, especially at the L3, L4, and L5 levels. However, at the S1 level, both systems exhibit similar effectiveness, underscoring the importance of understanding each system's specific advantages for optimization of surgical complications. [ABSTRACT FROM AUTHOR]

Thread shape is regarded as an important factor influencing the fixation strength and osseointegration of bone screws. However, commercial pedicle screws with a V-shaped thread are prone to generating stress concentration at the bone-screw interface, thereby increasing the risk of screw loosening. Thus, modification of the pedicle-screw thread is imperative. This study aimed to investigate the fixation stability of pedicle screws with the new undercut thread design in comparison to pedicle screws with a V-shaped thread. In vitro cadaveric biomechanical test and finite element analysis (FEA). Pedicle screws with the undercut thread (characterized by a flat crest feature and a tip-facing undercut feature) were custom-manufactured, whereas those with the V-shaped thread were procured from a commercial supplier. Fixation stability was assessed by the cyclic nonpullout compressive biomechanical testing on cadaveric female osteoporotic vertebrae. The vertical displacement and rotation angle of the 2 types of pedicle screws were calculated every 100 cycles to evaluate their resistance to migration and rotation. FEA was conducted to investigate the stress distribution and bone damage at the bone-screw interface for both types of pedicle screws. Biomechanical testing revealed that the pedicle screws with the undercut thread exhibited significantly lower vertical displacement and rotation angles than the pedicle screws with the V-shape thread (p <0.05). FEA results demonstrated a more uniform stress distribution in the bone surrounding the thread in the undercut design than in the V-shape design. Additionally, bone damage resulting from the pedicle screw was lower in the undercut design than in the V-shape design. Pedicle screws with an undercut thread are less prone to migration and rotation and thus more stable in the bone than those with a V-shape thread. The undercut thread design may reduce the incidence of pedicle-screw loosening. [ABSTRACT FROM AUTHOR]

Background: Various strategies have been used to reduce pedicle screw loosening following lumbar instrumented fusion, but all strategies have limitations. In this prospective multicenter cohort study, outcomes of elderly patients with reduced bone density who underwent primary or revision fusion surgery using a novel technique of pedicle screw augmentation with demineralized bone fiber (DBF) anchors were evaluated. Methods: This study included elderly patients (aged >65 years) with dual-energy x-ray absorptiometry-confirmed reduced bone density who required lumbar pedicle screw fixation and were treated with supplemental DBF allograft anchors during primary or revision surgery. The need for DBF anchors was determined by evaluating preoperative computed tomography (CT) scans (for revision surgery) and by the surgeons’ tactile feedback intraoperatively during pedicle screw insertion and removal. After determining the pedicle screw void diameter with a sizing instrument, DBF anchors and pedicle screws of the same diameter were placed into the void. CT scans were obtained on postoperative day 2 to assess pedicle breach, pedicle fracture, or anchor material extrusion and at 6 and 12 months postoperatively to assess screw loosening. Thereafter, to minimize radiation exposure, CT scans were only performed for recurrence of pain. Results: Twenty-three patients (79% women; mean age, 74 years) received 50 lumbosacral pedicle screws augmented with DBF anchors. Most surgeries (n = 18, 78%) were revisions, and most anchors were inserted into revision pedicle screw trajectories (n = 33, 66%). Day-2 CT scans revealed no pedicle breach/fracture or extrusion of anchor material. During a mean follow-up of 15 months (12–20 months), no screw loosening was detected, and no patient required pedicle screw revision surgery. There were no adverse events attributable to DBF allografts. Conclusions: DBF allograft anchors appear to be safe and effective for augmenting pedicle screws during revision surgeries in female elderly patients with reduced bone density. Clinical Relevance: Clinically, DBF reduced the rate of pedicle screw loosening in patients with reduced bone density. A significant reduction in screw loosening can decrease the need for revision surgeries, which are costly and carry additional risks. Enhanced bone integration from the DBF may promote better healing and long-term stability. [ABSTRACT FROM AUTHOR]

Objective: For degenerative diseases accompanied by cervical malalignment, the starting and ending points of fixation for better cervical sagittal alignment and clinical results are not as clear as the thoracolumbar region. In this study we aimed to compare the effects of posterior subaxial cervical fixation (PSCF), posterior cervical fixation extending to the upper thoracic region and posterior upper cervical fixation extending to the upper thoracic region on cervical sagittal alignment. Methods: Sixty‐three patients who underwent posterior cervical and cervical‐up thoracic fixation were retrospectively analyzed in a comparative study. The procedures that we performed from May 2019 to March 2022 on these 63 patients were: (1) C3‐C6 group—posterior subaxial cervical fixation; (2) Subaxial‐T2 group—posterior subaxial cervicothoracic fixation (PSCTF); (3) C2‐T2 upper thoracic posterior fixation group. The C3‐C6 group had 27 patients, Subaxial‐T2 group had 24, and C2‐T2 group had 12. We determined the minimum follow‐up period as 12 months. C0‐2, C2‐7 lordosis angle, sagittal vertical axis (SVA), C2 slope, C7 slope, T1 slope, cervical slope, neck slope, and thoracic inlet angle (TIA) measurements were made in three patient groups. Comparatively, cervical sagittal alignment was evaluated. Result: In the C2‐T2 group, a significant increase in C2‐C7 lordosis, decrease in C2 slope, and increase in TS‐CL were observed. Significant C2‐C7 lordosis decrease, C2 slope increase, and TS‐CL decrease were observed in the C3‐C6 group. A significant increase in C2‐C7 lordosis and a decrease in C2 slope were observed in the subaxial‐T2 group. No significant change was observed in the TS‐CL angle. Conclusion: In cervical degenerative disorders accompanied by cervical malalignment, we recommend the C2‐T2 fixation method, which provides the desired C2‐C7 lordosis, SVA within the normal range, and the best Neck Disability Index results. [ABSTRACT FROM AUTHOR]

Study Design: Biomechanical study. Purpose: To investigate the mechanical characteristics of bone models created from medical images. Overview of Literature: Recent advancements in three-dimensional (3D) printing technology have affected its application in surgery. However, a notable gap exists in the analyses of how patient's dimorphism and variations in vertebral body anatomy influence the maximum insertional torque (MIT) and pullout strength (POS) of pedicle screws (PS) in osteoporotic vertebral bone models derived from medical images. Methods: Male and female patients with computed tomography data were selected. Dimensions of the first thoracic (T1), fourth lumbar (L4), and fifth lumbar (L5) vertebrae were measured, and bone models consisting of the cancellous and cortical bones made from polyurethane foam were created. PS with diameters of 4.5 mm, 5.5 mm, and 6.5 mm were used. T1 PS were 25 mm long, and L4 and L5 PS were 40 mm long. The bone models were secured with cement, and the MIT was measured using a calibrated torque wrench. After MIT testing, the PS head was attached to the machine's crosshead. POS was then calculated at a crosshead speed of 5 mm/min until failure. Results: The L4 and L5 were notably larger in female bone models, whereas the T1 vertebra was larger in male bone models. Consequently, the MIT and POS for L4 and L5 were higher in female bone models across all PS diameters than in male bone models. Conversely, the MIT for T1 was higher in male bone models across all PS; however, no significant differences were observed in the POS values for T1 between sexes. Conclusions: The mechanical properties of the proposed bone models can vary based on the vertebral structure and size. For accurate 3D surgical and mechanical simulations in the creation of custom-made medical devices, bone models must be constructed from patient-specific medical images. [ABSTRACT FROM AUTHOR]

Abstract Background This study retrospectively compared short-term clinical outcomes and complications of minimally invasive surgery transforaminal lumbar interbody fusion(MIS-TLIF)and endoscopic lumbar interbody fusion(Endo-LIF))for two-segmental lumbar degenerative disease, aiming to guide spine surgeons in selecting surgical approaches. Methods From January 2019 to December 2023, 30 patients were enrolled,15 in the MIS-TLIF group and 15 in the Endo-LIF group. All patients were followed up for more than 3 months after surgery and the following information was recorded: (1)surgery time, difference in hemoglobin between preoperative and postoperative, surgical costs, first time out of bed after operation, postoperative hospitalization time, postoperative complication; (2) ODI score (The Oswestry Disability Index), leg and back VAS score (Visual Analogue Scale), and lumbar vertebra JOA score (Japanese Orthopaedic Association Scores); (3) MacNab score at final follow-up to assess clinical outcome, CT to evaluate lumbar fusion. Results There were significant differences between the two groups regarding operation time and cost, with the MIS-TLIF group performing significantly better. Intraoperative bleeding was considerably less in the Endo-LIF group compared to the MIS-TLIF group. However, there were no significant differences in the time of the first postoperative ambulation, postoperative hospitalization time, and postoperative complications. There was no significant difference in preoperative VAS, ODI, and JOA between the two surgical groups There were no significant differences in VAS(leg), ODI, and JOA scores between the two groups before and at 1 day,7 days, 1 month, 3 months and final follow-up. However, at 1 day postoperatively, the VAS( back)score in the Endo-LIF group was lower than that in the MIS-TLIF group, and the difference was statistically significant. At the final follow-up, all patients achieved grade III and above according to the Bridwell criteria, and there was no significant difference between the two surgical groups compared to each other. According to the MacNab score at the final follow-up, the excellent rate was 80.00% in the Endo-LIF group and 73.33% in the MIS-TLIF group, with no significant difference between the two groups. Conclusion There was no significant difference in short-term efficacy and safety between Endo-LIF and MIS-TLIF for two-segment degenerative lumbar diseases. MIS-TLIF has a shorter operative time and lower costs, while Endo-LIF causes less tissue damage, blood loss, and early postoperative pain, aiding long-term recovery. Both MIS-TLIF and Endo-LIF are promising for treating two-segment lumbar degenerative disease. The choice of a surgical procedure depends on the patient’s financial situation, their ability to tolerate surgery, and the surgeon’s expertise.

Introduction: Pedicle screws are commonly used in fixation to treat various spinal disorders. However, screw loosening is a prevalent complication, particularly in patients with osteoporosis. Various biomechanical studies have sought to address this issue, but the optimal depth and trajectory to increase the fixation strength of pedicle screws remain controversial. Therefore, a biomechanical study was conducted using finite element models. Methods: Three-dimensional finite element models of the L3 vertebrae were developed from the preoperative computed tomography images of nine patients with osteoporosis and nine patients without who underwent spine surgery. Unicortical and bicortical pedicle screws were inserted into the center and into the anterior wall of the vertebrae, respectively, in different trajectories in the sagittal plane: straightforward, cephalad, and caudal. Subsequently, three different external loads were applied to each pedicle screw at the entry point: axial pullout, craniocaudal, and lateromedial loads. Nonlinear analysis was conducted to examine the fixation strength of the pedicle screws. Results: Irrespective of osteoporosis, the bicortical pedicle screws had greater fixation strength than the unicortical pedicle screws in all trajectories and external loads. The fixation strength of the bicortical pedicle screws was not substantially different among the trajectories against any external loads in the nonosteoporotic vertebrae. However, the fixation strength of the bicortical pedicle screws against craniocaudal load in the cephalad trajectory was considerably greater than those in the caudal (P=0.016) and straightforward (P=0.023) trajectories in the osteoporotic vertebrae. However, this trend was not observed in pullout and lateromedial loads. Conclusions: Our results indicate that bicortical pedicle screws should be used, regardless of whether the patient has osteoporosis or not. Furthermore, pedicle screws should be inserted in the cephalad trajectory in patients with osteoporosis.

Introduction: Pedicle screw placement plays a crucial role in treating various cases such as fractures, scoliosis, degenerative spine issues, and kyphosis, reinforcing all three spinal columns simultaneously. While three-dimensional navigation-assisted pedicle screw placement is considered superior, the freehand technique relies on anatomical landmarks and tactile feedback, with observed low complication rates. MATERIALS AND METHODS: This was a prospective single-center study conducted over a period of 3 years. It included all patients of dorsal, lumbar, and sacral spinal instability of myriad etiology. Previously operated patients and sick obtunded patients were excluded from the study. Results: In our study, we included 102 patients including 62 (60.7%) males and 40 (39.2%) females. More than half of patients were young in the age group of 20–50 years. Our study population had a varied etiology with 43.1% of patients having vertebral column instability due to trauma. The other etiologies were spondylolisthesis and lumbar canal stenosis (39.2%), Pott’s spine (11.7%), tumors (2.9%), and osteoporotic fractures (2.9%). Majority of patients (44.1%) presented with lower backache with radiculopathy. All the transpedicular screws inserted were evaluated by C-arm to assess for screw fixation. In the first year of our study, an average of 4 anteroposterior (AP) and 4 lateral C-arm X-ray shots were taken per screw placement. In the next year, an average of 3 AP and 3 lateral shots and finally in the last year of our study only 2 AP and 2 lateral C-arm X-ray shots were taken per screw placement. Out of 650 screws placed, 4 screws were identified to cause breach with maximum breaches in the lumbar spine fixation. In dorsal spine fixation, there was 1 lateral breach at D10. In lumbar spine fixation, there were 3 breaches: two medial one each at L4 and L5 and one anterior at L2 level. The various complications include wound infection, temporary and permanent neurological deficit, screw breakage, screw misplacement, cerebrospinal fluid leaks, nonunion, and spinal epidural hematoma. Conclusions: Our study has provided strong encouragement to persist with the freehand technique in transpedicular fixation surgeries after a certain number of cases given the minimal breaches and complications observed. There are subtle technical nuances as we increase the number of cases with less exposure of anatomical landmarks and X-rays. Success hinges on experience, adherence to technique, and thorough preoperative planning. Further research and extended follow-up periods are necessary to firmly establish this technique as the gold standard.