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.
CONCLUSIONS: 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.

OBJECTIVE: To propose a screw algorithm and investigate the anatomical feasibilities and clinical outcomes of five distinct fixation methods for C2-3 fused vertebra with high-ridding vertebral arteries (VA) (HRVA) when the C2 pedicle screw placement is unfeasible.
METHODS: Thirty surgical patients with congenital C2-3 fusion, HRVA, and atlantoaxial dislocation (AAD) were included. We designed a algorithm for alternative screw implantation into C2-3 fused vertebrae, including C2 pedicle screw with in-out-in (passing VA groove) technique (in-out-in screw), subfacetal screw, translaminar screw, lateral mass screw, C3 pedicle screw. VA diameter and position, C2 and C3 pedicles, superior facets, fused lamina, and fused lateral mass dimensions were evaluated for screw implantation indication. Implant failure, reduction loss, implant placement accuracy were investigated by computed tomography.
RESULTS: A total of 5 VAs were identified as distant VAs; a total of 2 VAs were categorized as occlusive VAs. Sufficient dimension of lateral mass and lamina provided the broadest indications for screw implantation, while the distant or occlusive VA provided the most limited indications for in-out-in screw. The indications of five alternative methods ranged from narrowest to widest as follows: in-out-in screw, C3 pedicle screw, subfacetal screw, translaminar screw, lateral mass screw. The translaminar screws and the lateral mass screws increased the probability of implant failure. All patients who received in-out-in screws, C3 pedicle screws, and subfacetal screws achieved fusion. The accuracy ranged from lowest to highest as follows: C3 pedicle screw, lateral mass screw, in-out-in screw, subfacetal screw, translaminar screw. No translaminar screws deviated.
CONCLUSIONS: The algorithm proved to be a valuable tool for screw selection in cases of C2-3 fused vertebrae with HRVAs. The subfacetal screw, boasting broad indications, a high fusion rate, and exceptional accuracy, stood as the primary preferred alternative.

UNASSIGNED: This study aims to devise and assess an automated measurement framework for lumbar pedicle screw parameters leveraging preoperative computed tomography (CT) scans and a deep learning algorithm.
UNASSIGNED: A deep learning model was constructed employing a dataset comprising 1410 axial preoperative CT images of lumbar pedicles sourced from 282 patients. The model was trained to predict several screw parameters, including the axial angle and width of pedicles, the length of pedicle screw paths, and the interpedicular distance. The mean values of these parameters, as determined by two radiologists and one spinal surgeon, served as the reference standard.
UNASSIGNED: The deep learning model achieved high agreement with the reference standard for the axial angle of the left pedicle (ICC = 0.92) and right pedicle (ICC = 0.93), as well as for the length of the left pedicle screw path (ICC = 0.82) and right pedicle (ICC = 0.87). Similarly, high agreement was observed for pedicle width (left ICC = 0.97, right ICC = 0.98) and interpedicular distance (ICC = 0.91). Overall, the model\'s performance paralleled that of manual determination of lumbar pedicle screw parameters.
UNASSIGNED: The developed deep learning-based model demonstrates proficiency in accurately identifying landmarks on preoperative CT scans and autonomously generating parameters relevant to lumbar pedicle screw placement. These findings suggest its potential to offer efficient and precise measurements for clinical applications.

UNASSIGNED: To investigate the effectiveness of computer-assisted and robot-assisted atlantoaxial pedicle screw implantation for the treatment of reversible atlantoaxial dislocation (AAD).
UNASSIGNED: The clinical data of 42 patients with reversible AAD admitted between January 2020 and June 2023 and met the selection criteria were retrospectively analyzed, of whom 23 patients were treated with computer-assisted surgery (computer group) and 19 patients were treated with Mazor X spinal robot-assisted surgery (robot group). There was no significant difference in gender, age, T value of bone mineral density, body mass index, etiology, and preoperative Japanese Orthopaedic Association (JOA) score, Neck Dysfunction Index (NDI) between the two groups ( P>0.05). The operation time, screw implantation time, intraoperative blood loss, hand and wrist radiation exposure, and complications were recorded and compared between the two groups. Gertzbein classification was used to evaluate the accuracy of screw implantation. JOA score and NDI were used to evaluate the function before operation, at 3 days after operation, and at last follow-up. At last follow-up, the status of screws and bone fusion were observed by neck three-dimensional CT.
UNASSIGNED: The operation time and hand and wrist radiation exposure of the computer group were significantly longer than those of the robot group ( P<0.05), and there was no significant difference in the screw implantation time and intraoperative blood loss between the two groups ( P>0.05). All patients were followed up 11-24 months, with an average of 19.6 months. There was no significant difference in the follow-up time between the two groups ( P>0.05). There was no significant difference in the accuracy of screw implantation between the two groups ( P>0.05). Except for 1 case of incision infection in the computer group, which improved after antibiotic treatment, there was no complication such as nerve and vertebral artery injury, screw loosening, or breakage in the two groups. The JOA score and NDI significantly improved in both groups at 3 days after operation and at last follow-up ( P<0.05) compared to those before operation, but there was no significant difference between the two groups ( P>0.05). At last follow-up, 21 patients (91.3%) in the computer group and 18 patients (94.7%) in the robot group achieved satisfactory atlantoaxial fusion, and there was no significant difference in the fusion rate between the two groups ( P>0.05).
UNASSIGNED: Computer-assisted or robot-assisted atlantoaxial pedicle screw implantation is safe and effective, and robotic navigation shortens operation time and reduces radiation exposure.
UNASSIGNED: 探讨计算机导航和机器人导航辅助寰枢椎椎弓根螺钉植入治疗可复性寰枢椎脱位（atlantoaxial dislocation，AAD）的疗效。.
UNASSIGNED: 回顾分析2020年1月—2023年6月收治且符合选择标准的42例可复性AAD患者，其中23例采用计算机导航辅助手术（计算机组），19例采用Mazor X脊柱机器人导航辅助手术（机器人组）。两组患者性别、年龄、骨密度T值、身体质量指数、病因及术前日本骨科协会（JOA）评分、颈部功能障碍指数（NDI）等基线资料比较差异均无统计学意义（ P>0.05）。记录并比较两组患者手术时间、螺钉植入时间、术中出血量、手腕部辐射暴露量及并发症发生情况；采用Gertzbein分类法进行植钉准确度评估；术前、术后3 d及末次随访时采用JOA评分和NDI评价功能；末次随访时通过颈部三维CT观察螺钉状态以及骨融合情况。.
UNASSIGNED: 所有患者均顺利完成手术，计算机组手术时间和手腕部辐射暴露量均明显多于机器人组（ P<0.05），两组螺钉植入时间及术中出血量比较差异均无统计学意义（ P>0.05）。所有患者均获随访，随访时间11～24个月，平均19.6个月；两组随访时间比较差异无统计学意义（ P>0.05）。术后采用Gertzbein分类法评估，两组均为安全植钉，两组螺钉准确度比较差异无统计学意义（ P>0.05）。除计算机组出现1例切口感染，经抗生素治疗后好转外，两组均未发生神经、椎动脉损伤及螺钉松动、断裂等并发症。两组术后3 d及末次随访时JOA评分和NDI均较术前显著改善（ P<0.05），但两组间差异无统计学意义（ P>0.05）。末次随访时，计算机组21例（91.3%）、机器人组18例（94.7%）患者寰枢椎获满意骨融合，两组融合率比较差异无统计学意义（ P>0.05）。.
UNASSIGNED: 计算机导航和机器人导航辅助寰枢椎椎弓根螺钉植入治疗可复性寰枢椎脱位均安全有效，但机器人导航能缩短手术时间并减少辐射暴露。.

BACKGROUND: 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.
OBJECTIVE: The objective of this study was to assess the precision and safety of AR-assisted pedicle screw placement in the cervical spine.
METHODS: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
CONCLUSIONS: This study provides technical and clinical accuracy data that supports clinical trialing of AR-assisted subaxial cervical pedicle screw placement.

BACKGROUND: Long lateral mass screw (LLMS) technique for posterior cervical fusion has been performed in our hospital since 2019. In this study, the LLMS insertion technique, deviation rate, and insertion torque have been described. Moreover, several major concerns associated with LLMS have been adequately addressed.
METHODS: This study included 58 patients (43 men and 15 women) who had undergone LLMS surgery at our hospital during the four-year period from December 2019 to December 2023, and were evaluated using postoperative CT. The evaluation parameters included the screw length at each vertebral segment, screw angle in the sagittal section, distance between the screw heads, and complications.
RESULTS: The median screw length at C3 was 23.0 mm (22.0-24.0 mm), the screw angle was 36.1° (31.6-41.8°), and the distance between screw heads was 13.8 mm (11.6-17.2 mm). The median screw length at C4 was 22.0 mm (21.0-24.0 mm), the screw angle was 36.2° (28.7-40.7°), and the distance between screw heads was 15.9 mm (13.0-19.0 mm). The median screw length at C5 was 21.0 mm (20.0-22.0 mm), the screw angle was 35.6° (28.0-39.7°), and the distance between screw heads was 17.6 mm (15.1-20.4 mm). The median screw length for C6 was 20.0 mm (19.0-22.0 mm), the screw angle was 29.2° (25.2-36.8°), and the distance between screw heads was 20.4 mm (16.1-24.4 mm).
CONCLUSIONS: The major limitations of the LLMS technique were inadequate screw angle, difficulty inserting long screws, inadequate decompression, and the inability to perform cervical laminoplasty. However, these limitations did not substantially affect the efficiency of LLMS. LLMS has fewer complications and can insert longer screws than LMS.

UNASSIGNED: To describe the feasibility, safety and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with the high-riding vertebral artery (HRVA).
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UNASSIGNED: During the period January 2020 to September 2022, fifteen patients underwent posterior occipitocervical fixation in our department. All patients had unilateral HRVA on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 13 females aged 47 ± 11.9 years (range: 17-64 years). After the correction of the vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. A routine three-dimensional reconstructed CT examination was executed to confirm the trajectory of C2 pedicle screws post-operation, and a CT angiography examination was performed when necessary. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including anterior atlantodental interval (ADI), the distance of odontoid tip above Chamberlain line, and clivus-canal angle (CCA), were collected and compared by paired t-test.
UNASSIGNED: All 15 patients had atlas assimilation, among which 12 patients had C2-C3 fusion (Klippel-Feil syndrome). Mobilization of the HRVA was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were reached in all 15 patients. All the patients achieved bone fusion 6 months after surgery. No looseness and shift of internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative JOA score and the main radiological measurements were remarkably improved and statistically significant.
UNASSIGNED: C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

OBJECTIVE: Despite standardized biomechanical tests for spinal implants, we recently recognized pedicle screw failure to maintain the rod fixated as a clinical concern in scoliosis surgery. This occurrence study investigates the risk and magnitude of axial rod slip (ARS), its relation with technique and preventive measures.
METHODS: Retrospective multicenter review of all primary scoliosis cases (2018-2020) with > 1 year FU from three centers, instrumented with uniplanar screws and 5.5 mm CoCr rods (Mesa 2, Stryker Corporation, Kalamazoo, MI, USA). ARS was defined as > 1 mm change in residual distal rod length from the screw in the lowest instrumented vertebra (LIV) and assessed by two independent observers. Slip distance, direction, relation to distal screw density and time of observation were recorded, as well as the effect of ARS on caudal curve increase. To prevent slip, more recent patients were instrumented with a different end-of-construct screw (Reline, NuVasive Inc. San Diego, CA, USA) and analyzed for comparison.
RESULTS: ARS risk was 27% (56/205) with a distance of 3.6 ± 2.2 mm, predominantly convex. 42% occurred before 4 months, the rest before 1 year. The caudal curve substantially increased three times more often in patients with ARS. Interobserver reliability was high and slip was in the expected direction. ARS was unrelated to distal screw density. Remarkable variation in ARS rates (53%, 31%, 13%) existed between the centers, while there was no difference in mean screw density (≈1.3 screws/level) or curve correction (≈60%). Revision surgery for ARS was required in 2.9% (6/207). Using the different end-of-construct screw, ARS risk was only 2% (1/56) and no revisions were required.
CONCLUSIONS: This study demonstrates the prevalence of axial rod slip at the end of construct in scoliosis surgery and its clinical relevance. While minimal ARS can be subclinical, ARS should not be mistaken for adding on. The most severe ARS predominantly occurred convex at the high-loaded distal screw when L3 was the LIV. Longer constructs (LIV L3 or L4) have a higher risk of ARS. The minimal risk of ARS with another end-of-construct screw underscores the influence of screw type on ARS occurrence in our series. Further research is essential to refine techniques and enhance patient outcomes.

UNASSIGNED: Biomechanical study.
UNASSIGNED: To investigate the mechanical characteristics of bone models created from medical images.
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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 patientspecific medical images.

OBJECTIVE: 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).
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.