Accuracy and clinical characteristics of robot-assisted cervical spine surgery: a systematic review and meta-analysis.

PURPOSE: To evaluate the accuracy and feasibility of robot-assisted cervical screw placement and factors that may affect the accuracy. METHODS: A comprehensive search was made on PubMed, Embase, Cochrane Library, Web of Science, CNKI, and Wanfang Med for the selection of potential eligible literature. The outcomes were evaluated in terms of the relative risk (RR) or standardized mean difference (MD) and corresponding 95% confidence interval (CI). Subgroup analyses of the accuracy of screw placement at different cervical segments and with different screw placement approaches were performed. A comparison was made between robotic navigation and conventional freehand cervical screw placement. RESULTS: Six comparative cohort studies and five case series studies with 337 patients and 1342 cervical screws were included in this study. The perfect accuracy was 86% (95% CI, 82-89%) and the clinically acceptable rate was 98% (95% CI, 95-99%) in robot-assisted cervical screw placement. The perfect accuracy of robot-assisted C1 lateral mass screw placement was the highest (96%), followed by C6-7 pedicle screw placement (93%) and C2 pedicle screw placement (86%), and the lowest was C3-5 pedicle screw placement (75%). The open approach had a higher perfect accuracy than the percutaneous/intermuscular approach (91% vs 83%). Compared with conventional freehand cervical screw placement, robot-assisted cervical screw placement had a higher accuracy, a lower incidence of perioperative complications, and less intraoperative blood loss. CONCLUSION: With good collaboration between the operator and the robot, robot-assisted cervical screw placement is accurate and feasible. Robot-assisted cervical screw placement has a promising prospect.

The positional consistency between guidewire and cannulated or solid screw in robot-assisted spinal internal fixation surgery.

BACKGROUND: This study aimed to investigate the positional consistency between the guidewire and the screw in spinal internal fixation surgery. METHODS: This study involved 64 patients who underwent robot-assisted thoracic or lumbar pedicle screw fixation surgery. Guidewires were inserted with the assistance of the Tirobot. Either cannulated screws or solid screws were inserted. Guidewire and screw accuracy was measured using CT images based on the Gertzbein and Robbins scale. The positional consistency between guidewire and screw was evaluated based on the fused CT images, which could graphically and quantitatively demonstrate the consistency. The consistency was evaluated based on a grading system that considered the maximum distance and angulation between the centerline of the guidewire and the screw in the region of the pedicle. RESULTS: A total of 322 screws were placed including 206 cannulated ones and 116 solid ones. Based on the Gertzbein and Robbins scale, 97.5% of the guidewires were grade A, and 94.1% of the screws were grade A. Based on our guidewire-screw consistency scale, 85% in cannulated group, and 69.8% in solid group, were grade A. Both solid and cannulated screws may alter trajectory compared to the guidewires. The positional accuracy and guidewire-screw consistency in the solid screw group is significantly worse than that in the cannulated screw group. The cortical bone of the pedicle has a positive guide effect on either solid or cannulated screws. CONCLUSION: The pedicle screws may alter trajectory despite the guidance of the guidewires. Solid screws show worse positional accuracy and guidewire-screw consistency compared with cannulated screws. Trial registration The study was retrospectively registered and approved by our center's institutional review board.

Impact of optical navigation variables on the accuracy of robot-assisted surgery: a study of the TIANJI Robot system.

This study aims to explore factors related to optical navigation that interfere with the accuracy of robot-assisted surgery, specifically focusing on the TIANJI Robot system. A measurement model was created to assess the accuracy of the TIANJI Robot system in simulated screw placement. Deviation between actual and planned positions was measured using a three-coordinate machine. Various experiments were conducted to investigate the impact of different optical navigation factors on screw placement accuracy. Deviations were measured at different distances (ranging from 1.2 to 2.2 m) between the optical navigation stereo camera and the tracker, with each distance being tested 50 times. The distance between the optical camera and patient tracker was set at 1.4 m. Deviations were also measured at different angles between the camera and robot tracker, repeated over 25 times for each angle. Data were analyzed using mean and standard deviation, with line charts illustrating deviation changes based on distance and angle details. Within the range of the TIANJI Robot system's optical navigation (1.2-2.2 m), deviation increased as distance increased (χ2 = 479.107, P < 0.001). The robotic system demonstrated high and consistent accuracy (mean deviation: 0.332 mm ± 0.067 mm) when the relative angle between the optical camera and tracker was below 40°. The accuracy of the TIANJI Robot system was found to be influenced by relative distance and angle between the optical camera and tracker during screw placement procedures. Surgeons are recommended to set a relative distance of 1.4-1.5 m between the optical camera and patient tracker, with a relative angle below 40° when placing and adjusting optical tracking devices.

Robotic navigation during spine surgery: an update of literature.

INTRODUCTION: The application of robotic navigation during spine surgery has advanced rapidly over the past two decades, especially in the last 5 years. Robotic systems in spine surgery may offer potential advantages for both patients and surgeons. This article serves as an update to our previous review and explores the current status of spine surgery robots in clinical settings. AREAS COVERED: We evaluated the literature published from 2020 to 2022 on the outcomes of robotics-assisted spine surgery, including accuracy and its influencing factors, radiation exposure, and follow-up results. EXPERT OPINION: The application of robotics in spine surgery has driven spine surgery into a new era of precision treatment through a form of artificial intelligence assistance that compensates for the limitations of human abilities. Modularized robot configurations, intelligent alignment and planning incorporating multimodal images, efficient and simple human - machine interaction, accurate surgical status monitoring, and safe control strategies are the main technical features for the development of orthopedic surgical robots. The use of robotics-assisted decompression, osteotomies, and decision-making warrants further study. Future investigations should focus on patients' needs while continuing to explore in-depth medical - industrial collaborative development innovations that improve the overall utilization of artificial intelligence and sophistication in disease treatment.

Robot-assisted percutaneous pars-pedicle screw fixation for treating Hangman's fracture.

BACKGROUND: This study aimed to evaluate the safety and efficacy of robot-assisted percutaneous pars-pedicle screw fixation surgery for treating Hangman's fracture. METHODS: The study involved 33 patients with Hangman's fracture who underwent robot-assisted fixation surgery using cannulated pars-pedicle screws through a percutaneous approach. The primary parameter evaluated was the accuracy of the screws according to the Gertzbein-Robbins scale, using postoperative CT images. Secondary parameters included the duration of surgery, intraoperative blood loss, postoperative hospital stay, and neurovascular injury. RESULTS: A total of 60 pars-pedicle screws were placed in 33 patients. Based on the Levine and Edwards classification, the patients included 12 cases of type I, 15 cases of type II, five cases of type IIa, and one atypical case. The average operative time was 92.4 ± 37.4 min, and the average blood loss was 22.4 ± 17.9 ml. Fifty-five of 60 screws were successfully placed within the bone. No screw-related neurovascular injury was observed, and satisfactory reduction was achieved in all cases. CONCLUSION: Robot-assisted percutaneous pars-pedicle screw fixation is a safe and feasible method for treating Hangman's fracture. TRIAL REGISTRATION: The study was retrospectively registered and approved by our center's institutional review board.

Molecular Mechanism of Long Noncoding RNA SNHG14 in Osteogenic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells through the NEDD4L/FOXA2/PCP4 Axis.

Bone marrow-derived mesenchymal stem cells (BMSCs) have a superior potential of osteogenic differentiation (OD) and a promising stem cell type to treat bone defects. This study sought to investigate the molecular mechanism of long noncoding RNA small nucleolar RNA host gene 14 (SNHG14) in OD of BMSCs. Western blot analysis or RT-qPCR showed that SNHG14, neural precursor cell expressed developmentally downregulated 4-like (NEDD4L), and Purkinje cell protein 4 (PCP4) were upregulated whereas forkhead box A2 (FOXA2) was declined in OD of BMSCs. RT-qPCR and cell staining showed that SNHG14 downregulation repressed OD of BMSCs, as manifested by reductions in osteopontin and osteocalcin levels, the mineralization degree, and alkaline phosphatase activity. RNA/Co/chromatin immunoprecipitation and dual-luciferase assays and determination of mRNA stability and ubiquitination level showed that SNHG14 bound to human antigen R improves NEDD4L mRNA stability and expression, further promoted FOXA2 ubiquitination to inhibit FOXA2 expression, and then reduced FOXA2 enrichment on the PCP4 promoter to upregulate PCP4 transcription. Functional rescue experiments showed that the overexpression of NEDD4L or PCP4 and knockdown of FOXA2 both attenuated the inhibition of SNHG14 downregulation on OD of BMSCs. Overall, our findings suggested that SNHG14 promoted OD of BMSCs through the NEDD4L/FOXA2/PCP4 axis.

Posterior atlantoaxial internal fixation using Harms technique assisted by 3D-based navigation robot for treatment of atlantoaxial instability.

BACKGROUND: To evaluate the accuracy of screw placement using the TiRobot surgical robot in the Harms procedure and to assess the clinical outcomes of this technique. METHODS: This retrospective study included 21 patients with atlantoaxial instability treated by posterior atlantoaxial internal fixation (Harms procedure) using the TiRobot surgical robot between March 2016 and June 2021. The precision of screw placement, perioperative parameters and clinical outcomes were recorded. Screw placement was assessed based on intraoperative guiding pin accuracy measurements on intraoperative C-arm cone-beam computed tomography (CT) images using overlay technology and the incidence of screw encroachment identified on CT images. RESULTS: Among the 21 patients, the mean age was 44.8 years, and the causes of atlantoaxial instability were os odontoideum (n = 11), rheumatoid arthritis (n = 2), unknown pathogenesis (n = 3), and type II odontoid fracture (n = 5). A total of 82 screws were inserted with robotic assistance. From intraoperative guiding pin accuracy measurements, the average translational and angular deviations were 1.52 ± 0.35 mm (range 1.14-2.25 mm) and 2.25° ± 0.45° (range 1.73°-3.20º), respectively. Screw placement was graded as A for 80.5% of screws, B for 15.9%, and C for 3.7%. No complications related to screw misplacement were observed. After the 1-year follow-up, all patients with a neurological deficit experienced neurological improvement based on Nurick Myelopathy Scale scores, and all patients with preoperative neck pain reported improvement based on Visual Analog Scale scores. CONCLUSIONS: Posterior atlantoaxial internal fixation using the Harms technique assisted by a 3D-based navigation robot is safe, accurate, and effective for treating atlantoaxial instability.

Severity of Hospitalized Children with Anti-NMDAR Autoimmune Encephalitis.

Background: Information on the clinical characteristics and severity of autoimmune encephalitis with antibodies against the N-methyl-d-aspartate receptor (NMDAR) in children is attracting more and more attention in the field of pediatric research. Methods: In this retrospective cohort study, all cases (n = 67) were enrolled from a tertiary children's hospital, from 2017 to 2020. We compared severe cases that received intensive care unit (ICU) care with nonsevere cases that did not receive ICU care and used machine learning algorithm to predict the severity of children, as well as using immunologic and viral nucleic acid tests to identify possible pathogenic triggers. Results: Mean age of children was 8.29 (standard deviation 4.09) years, and 41 (61.19%) were girls. Eleven (16.42%) were admitted to the ICU, and 56 (83.58%) were admitted to neurology ward. Ten individual parameters were statistically significant differences between severe cases and nonsevere cases (P < .05), including headache, abnormal mental behavior or cognitive impairment, seizures, concomitant tumors, sputum/blood pathogens, blood globulin, blood urea nitrogen, blood immunoglobulin G, blood immunoglobulin M, and number of polynucleated cells in cerebrospinal fluid. Random forest regression model presented that the overall prediction power of severity reached 0.806, among which the number of polynucleated cells in cerebrospinal fluid contributed the most. Potential pathogenic causes exhibited that the proportion of mycoplasma was the highest, followed by Epstein-Barr virus. Conclusion: Our findings provided evidence for early identification of autoimmune encephalitis in children, especially in severe cases.

Accuracy evaluation of cone beam computed tomography applied to measure peri-implant bone thickness in living patients: an ex vivo and in vivo experiment.

OBJECTIVES: This study aims to study the accuracy of cone beam computed tomography (CBCT) for measuring peri-implant bone thickness in living patients via a novel visualization method (NVM). MATERIAL AND METHODS: The validity of the NVM was verified ex vivo by measuring the same peri-implant bone thicknesses in bovine ribs by using raw postoperative CBCT (clinical measurement, CM), the visualized fused images obtained using the NVM (visualized fused measurement, VF), and hard tissue sections (gold standard measurement, GS). The NVM was applied by deconstructing the postoperative CBCT model into the Modelpost-bone and Modelimplant and replacing it with bone from preoperative CBCT and standard implant models, respectively. In vivo, 52 implants were included, and the VF of each implant was obtained using data processing methods similar to those used ex vivo. Then, we compared the results of CM and VF. RESULTS: Ex vivo, the VF was similar to GS, while CM usually underestimated the peri-implant bone thickness, especially at the implant shoulder (P < 0.01). In vivo, on CBCT, areas with a peri-implant bone thickness of 0-0.50 mm were not visible, while those with a thickness of 0.50-1.00 mm were occasionally visible. There was less underestimation of bone along the implant long axis. CONCLUSIONS: Thin peri-implant bones could be completely underestimated on CBCT. CBCT scans alone are insufficient to warrant surgical intervention. Our NVM facilitates the accurate visual assessment of implant dimensions. CLINICAL RELEVANCE: The thickness of peri-implant bone could be completely underestimated when thinner than 1.0 mm in living patients. Familiarity with these confusing CBCT results may help clinicians and patients avoid further unnecessary evaluation, misdiagnosis, and invasive treatment.

Analysis of clinical characteristics of 66 pediatric patients with B.1.617.2 (Delta) variant of COVID-19.

BACKGROUND: The aim of this study was to analyze the clinical characteristics of 66 pediatric patients with B.1.617.2 (Delta) variant of coronavirus disease 2019 (COVID-19). METHODS: Sixty-six pediatric patients with B.1.617.2 (Delta) variant of COVID-19 admitted to the hospital from July to August 2021 were classified into mild (n = 41) and moderate groups (n = 25). Clinical characteristics, laboratory data and dynamic trends in different time periods were analyzed retrospectively. RESULTS: There were no statistically significant differences in age, gender ratios and clinical symptoms between the mild group and the moderate group. All the patients in the moderate group had clusters of onsets, and the incubation period was shorter than that of the mild group. Within 24 hours of admission, the levels of erythrocyte sedimentation rate, cardiac troponin I, D-dimer in the moderate group were higher than that in the mild group (P < 0.05). The titers of immunoglobulin (Ig) G and IgM antibodies gradually increased after disease onset. Thirty-five (53.03%) children were tested positive for antibodies in 4-12 days. IgG increased gradually, while IgM decreased obviously in about 15 days after disease onset. The cycle threshold values of open reading frame 1ab and nucleocapsid protein gene in the severe acute respiratory syndrome coronavirus 2 genomes increased gradually on the 3rd, 6th, 9th, and 12th days after disease onset, compared with those in day 0. CONCLUSIONS: The symptoms of children with B.1.617.2 (Delta) variant of COVID-19 were mild. The description and analysis of the clinical characteristics and laboratory data can help medical staff to evaluate the condition of children with COVID-19 and to accumulate more clinical experience.

A prospective cohort study of the accuracy and safety of robot-assisted minimally invasive spinal surgery.

BACKGROUND: Robot-assisted open surgery (RA-OS) is now commonly used in traditional open-exposure spinal screw placement surgery. With the help of robots, robot-assisted minimally invasive surgery (RA-MIS) can achieve less bleeding and less tissue damage in percutaneous screw insertion. While the research comparing the safety and accuracy of screw placement between RA-MIS and RA-OS is insufficient. This study aims to compare the effects of RA-MIS and RA-OS in thoracic and lumbar spine. METHODS: This was a prospective cohort study evaluating 208 patients undergoing robot-assisted screw insertions from July 2020 to September 2021. Age, BMI, gender, screws accuracy, screws Gertzbein-Robbins grade, small joint invasion and perioperative outcomes (operation time, blood loss, postoperative hospital stay, comorbidity) were collected. A subgroup analysis was also performed according to disease, namely fracture, spondylolisthesis, and disc herniation. Data were analyzed using Stata/MP 14.0. Wilcoxon's signed rank test, Kruskal-Wallis test and Fisher's exact test were used for statistical tests and p < 0.05 was considered statistically significant. RESULTS: A total of 1030 screws were inserted; 368 minimally invasive screws and 662 open screws. The acceptability of screw insertion in the RA-MIS and RA-OS was 97.3% and 95.6% respectively. There was no statistical difference between the RA-MIS group and RA-OS group in age (p = 0.106), gender (p = 0.074), BMI (p = 0.181) and comorbidity (p = 0.203). Compared with RA-OS, RA-MIS had less blood loss (p < 0.001) and shorter postoperative hospital stay (p = 0.008). In the minimally invasive surgery group, the fracture subgroup had smaller screw deviation, less blood loss, and shorter operation time compared with the other subgroups (p < 0.01). Specifically, RA-MIS significantly reduced the postoperative hospital stay of patients with spondylolisthesis compared with RA-OS (p < 0.01). CONCLUSION: RA-OS and RA-MIS had equal accuracy and safety. Compared with open surgery, minimally invasive surgery reduced blood loss in each subgroup and shortened the postoperative hospital stay in the spondylolisthesis subgroup. Compared with the other subgroups under minimally invasive surgery, the fracture subgroup had less blood loss and shorter operation time. CLINICAL TRIAL REGISTRATION: NCT04040868. Registered 1 March 2019, https://clinicaltrials.gov/ct2/show/NCT04040868?cond=Accuracy+Study+of+Robot-assisted+Screw+Insertion+in+Spinal+Surgery&draw=2&rank=1 .

Chest CT features of children infected by B.1.617.2 (Delta) variant of COVID-19.

BACKGROUND: This study aimed to explore the imaging characteristics, diversity and changing trend in CT scans of pediatric patients infected with Delta-variant strain by studying imaging features of children infected with Delta and comparing the results to those of children with original COVID-19. METHODS: A retrospective, comparative analysis of initial chest CT manifestations between 63 pediatric patients infected with Delta variant in 2021 and 23 pediatric patients with COVID-19 in 2020 was conducted. Corresponding imaging features were analyzed. In addition, the changing trend in imaging features of COVID-19 Delta-variant cases were explored by evaluating the initial and follow-up CT scans. RESULTS: Among 63 children with Delta-variant COVID-19 in 2021, 34 (53.9%) showed positive chest CT presentation; and their CT score (1.10 ± 1.41) was significantly lower than that in 2020 (2.56 ± 3.5) (P = 0.0073). Lesion distribution: lung lesions of Delta cases appear mainly in the lower lungs on both sides. Most children had single lobe involvement (18 cases, 52.9%), 14 (41.2%) in the right lung alone, and 14 (41.2%) in both lungs. A majority of Delta cases displayed initially ground glass (23 cases, 67.6%) and nodular shadows (13 cases, 38.2%) in the first CT scan, with few extrapulmonary manifestations. The 34 children with abnormal chest CT for the first time have a total of 92 chest CT examinations. These children showed a statistically significant difference between the 0-3 day group and the 4-7 day group (P = 0.0392) and a significant difference between the 4-7 day group and the more than 8 days group (P = 0.0003). CONCLUSIONS: The early manifestations of COVID-19 in children with abnormal imaging are mostly small subpleural nodular ground glass opacity. The changes on the Delta-variant COVID-19 chest CT were milder than the original strain. The lesions reached a peak on CT in 4-7 days and quickly improved and absorbed after a week. Dynamic CT re-examination can achieve a good prognosis.

Learning curves of robot-assisted pedicle screw fixations based on the cumulative sum test.

BACKGROUND: In robot-assisted (RA) spine surgery, the relationship between the surgical outcome and the learning curve remains to be evaluated. AIM: To analyze the learning curve of RA pedicle screw fixation (PSF) through fitting the operation time curve based on the cumulative summation method. METHODS: RA PSFs that were initially completed by two surgeons at the Beijing Jishuitan Hospital from July 2016 to March 2019 were analyzed retrospectively. Based on the cumulative sum of the operation time, the learning curves of the two surgeons were drawn and fit to polynomial curves. The learning curve was divided into the early and late stages according to the shape of the fitted curve. The operation time and screw accuracy were compared between the stages. RESULTS: The turning point of the learning curves from Surgeons A and B appeared in the 18th and 17th cases, respectively. The operation time [150 (128, 188) min vs 120 (105, 150) min, P = 0.002] and the screw accuracy (87.50% vs 96.30%, P = 0.026) of RA surgeries performed by Surgeon A were significantly improved after he completed 18 cases. In the case of Surgeon B, the operation time (177.35 ± 28.18 min vs 150.00 ± 34.64 min, P = 0.024) was significantly reduced, and the screw accuracy (91.18% vs 96.15%, P = 0.475) was slightly improved after the surgeon completed 17 RA surgeries. CONCLUSION: After completing 17 to 18 cases of RA PSFs, surgeons can pass the learning phase of RA technology. The operation time is reduced afterward, and the screw accuracy shows a trend of improvement.

Benefits of Early Ambulation in Elderly Patients Undergoing Lumbar Decompression and Fusion Surgery: A Prospective Cohort Study.

OBJECTIVE: To evaluate the effects of early ambulation on elderly patients' postoperative physical functional outcomes, complications, 90-day readmission rate, and the length of postoperative hospital stay. METHODS: This is a prospective cohort study conducted between June 2019 and December 2019. The study enrolled 86 elderly patients (39 males) with newly diagnosed lumbar degenerative disease undergoing single-segment decompression and fusion surgerywere enrolled. Of all 86 patients, 39 voluntarily joined the early ambulation group, and 47 joined the regular ambulation group. The early ambulation group included patients ambulated within 4 h postoperatively, whereas the regular ambulation group included patients who were ambulatory at a minimum of 24 h after surgery. Participants' baseline characteristics, surgical information, ambulation ability, degree of pain, functional scores, postoperative complications, 90-day readmission rate, and length of postoperative hospital stay were recorded. RESULTS: Participants' baseline demographic characteristics were balanced between the early ambulation group and the regular ambulation group. The operative time and blood loss were similar between groups. The time before the first-time ambulation was 4 ± 0.5 h in the early ambulation group and 28 ± 4.5 h in the regular ambulation group. Ambulating distance was significantly longer in the early ambulation group compared with the regular ambulation group on the 1st (63 ± 45 vs 23 ± 60 m), the 2nd (224 ± 100 vs 101 ± 130 m), and the 3rd (280 ± 102.5 vs 190 ± 170 m) ambulation days based on generalized estimating equation analyses. Generalized estimating equation analyses also demonstrated that the ambulating time was longer in the early ambulation group compared with the regular ambulation group on the 1st (10 ± 5 vs 10 ± 5 min), the 2nd (19 ± 7 vs 15 ± 5 min), and the 3rd (22 ± 16.5 vs 27 ± 12 min) ambulation days. Patients in the regular ambulation group experienced a higher degree of pain than the early ambulation group patients, with an odds ratio of 1.627 (P = 0.002). Short-term functional independence was superior in the early ambulation group, with a lower Roland-Morris disability questionnaire score (P = 0.008) and Oswestry disability index (P < 0.001). The incidences of postoperative urinary retention (early ambulation group: 7.7%, regular ambulation group: 25.5%, P = 0.030) and ileus (early ambulation group: 0%, regular ambulation group: 12.8%, P = 0.030) were significantly higher in the regular ambulation group. The prevalence of at least one complication rate was significantly lower in the early ambulation group than in the regular ambulation group (early ambulation group, 23.1%; regular ambulation group, 46.8%, P = 0.022). The duration of indwelling of the drainage catheter was shorter in the early ambulation group (early ambulation group, 68 ± 24 h; regular ambulation group, 78 ± 20 h, P = 0.001), and the length of the postoperative hospital stay was also shorter in the early ambulation group (early ambulation group, 4 ± 0 days; regular ambulation group: 5 ± 2 days, P < 0.001). However, there was no statistical difference in the 90-day readmission rate between groups. CONCLUSION: Early ambulation improved patients' postoperative functional status, decreased the incidence of complications, and shortened postoperative hospital stay in elderly patients undergoing lumbar decompression and fusion surgery.

Drilling Speed and Bone Temperature of a Robot-assisted Ultrasonic Osteotome Applied to Vertebral Cancellous Bone.

STUDY DESIGN: An experimental investigation of a robot-assisted ultrasonic osteotome applied to vertebral cancellous bone. OBJECTIVE: The aim of this study was to investigate the effect of various ultrasonic parameter settings on temperature in the drilling site and penetration time and determine the most suitable parameters for efficient and safe robot-based ultrasonically assisted bone drilling in spinal surgery. SUMMARY OF BACKGROUND DATA: A robot-assisted ultrasonic osteotome device may be safe and effective for spinal drilling. METHODS: Sixty specimens of bovine vertebral cancellous were randomly assigned to one of six groups, which varied by mode of ultrasonic vibration (L-T and L) and feed rate (one percent [0.8 mm/s], two percent [1.6 mm/s], and three pecent [2.4 mm/s]). Maximum temperature in the drilling site and penetration time was recorded. RESULTS: Maximum temperature in the drilling site decreased as output power increased for L-T and L modes, was significantly lower for L-T compared to L mode at each feed rate and power setting, was significantly different at feed rates of 1.6 mm/s versus 0.8 mm/s and 2.4 mm/s versus 0.8 mm/s for L-T mode at an output power of 60 W and 84 W, but was not influenced by feed rate for L mode. Penetration time did not significantly improve as output power increased for both L-T and L modes, was significantly decreased with increased feed rates, but was not significantly different between L-T and L modes. CONCLUSION: The optimal parameters for applying a robot-assisted ultrasonic osteotome to vertebral cancellous bone are L-T mode, maximum output power of 120 W, and maximum feed rate of 2.4 mm/s.Level of Evidence: 4.

Risk Factors of Unsatisfactory Robot-Assisted Pedicle Screw Placement: A Case-Control Study.

OBJECTIVE: To identify potential risk factors of unsatisfactory screw position during robot-assisted pedicle screw fixation. METHODS: A retrospective analysis of robot-assisted pedicle screw fixation performed in Beijing Jishuitan Hospital from March 2018 to March 2019 was conducted. Research data was collected from the medical record and imaging systems. Univariate tests were performed on the potential risk factors (patient's characteristics and surgical factors) of unsatisfactory screw position during robot-assisted pedicle screw fixation. For statistically significant variables in univariate tests, a logistic regression test was used to identify independent risk factors for unsatisfactory screw position. RESULTS: A total of 780 pedicle screws placed in 163 robot-assisted surgeries were analyzed. The rate of perfect screw positions was 93.08%, and the unsatisfactory rate was 6.92%. In patients with severe obesity (body mass index ≥ 30 kg/m2) (odds ratio [OR], 2.459; 95% confidence interval [CI], 1.199-5.044; p = 0.014), osteoporosis (T ≤ -2.5) (OR, 1.857; 95% CI, 1.046-3.295; p = 0.034), and the segments 3 levels away from the tracker (OR, 2.216; 95% CI, 1.119-4.387; p = 0.022), robot-assisted pedicle screw placement has a higher risk of screw malposition. CONCLUSION: During robot-assisted pedicle screw placement for patients with severe obesity, osteoporosis, and segments 3 levels away from the tracker, vigilance should be maintained during surgery to avoid postoperative complications due to unsatisfactory screw position.

Ormosanine improves neuronal functions in spinal cord-injured rats by blocking peroxynitrite/calpain activity.

The present study was performed to evaluate the effects of ormosanine against spinal cord injury (SCI) in rats and to examine the possible molecular mechanism of action. SCI was induced using an impactor device, and rats were treated with ormosanine 10, 50 or 100 mg/kg, p.o., for 10 days after induction of SCI. The effect of ormosanine on SCI was determined by estimating neurological functions and cytokines and parameters of oxidative stress level were estimated in SCI rats. Quantitative reverse transcription polymerase chain reaction, Western blotting analysis and histopathological study were performed on spinal tissue of SCI rats. The data suggested that treatment with ormosanine reversed the alterations of neurological function in SCI rats. Moreover, the levels of cytokines, oxidative stress and reactive oxygen species production were reduced in the ormosanine treatment group compared to the SCI group. The levels of calpain and neuronal nitric oxide synthase activity were significantly reduced in the spinal tissue of the ormosanine treatment group compared to the SCI group. Moreover, ormosanine treatment reduced the percentage of viable neurons in the spinal tissue of SCI rats. In conclusion, the results of this study showed that ormosanine treatment had a protective effect against neuronal injury in spinal cord-injured rats by regulating the peroxynitrite/calpain activity.

The Assessment of Paravertebral Ossification Progression After Cervical Disc Arthroplasty Based on CT Images: A Long-term Follow-up.

OBJECTIVE: This study focused on the assessment of paravertebral ossification (PO) after cervical disc arthroplasty (CDA) using computed tomography (CT) images. METHODS: In this retrospective study, 52 patients (from 2004 to 2010) who received CDA at a single center were included (32 males). Preoperative and follow-up X-ray and CT images of all patients who underwent single-level CDA were collected. PO from the C2/3 to C7/T1 in each patient was graded based on a CT grading system. Each segment was divided into operative level, adjacent level, or non-adjacent level. The McAfee' classification system was used to grade PO using X-ray plain film. The range of motion (ROM) and scores of neurological symptoms (Japanese Orthopaedic Association [JOA] score and Neck Disability Index [NDI]) at both preoperative and final follow-up time were acquired. Progression and classification of PO in each group was compared using the chi-square test. ROM between groups were compared using independent t-test. JOA score and NDI between groups were compared using Mann-Whitney U test. RESULTS: The average follow-up time was 81.2 months. In comparison with the preoperative status, the progression of PO development in left and right areas (the Luschka joints areas) in the operative level groups was significantly more severe (area L,χ2 value = 36.612, P < 0.001; area R, χ2 value = 39.172, P < 0.001) than the non-adjacent level groups. In contrast, although the prevalence of PO in all areas of the adjacent level groups was higher than that of the non-adjacent level group in the same segments, there was no significant difference (P > 0.05) in the progression of PO development. The follow-up high-grade (grades III and IV) PO incidence rate using X-ray grading system (3.85%) was significantly lower than that using CT grading system in area L (42.31%) and R (38.46%), but close to that in area A (5.77%) and P (1.92%). The final follow-up ROM was not significantly different with preoperative ROM in patients with low-grade PO (9.47° ± 4.12° vs. 9.76° ± 3.69°, P = 0.794). However, in patients with high-grade PO, the final follow-up ROM was significantly lower than preoperative ROM (5.77° ± 3.32° vs. 9.28° ± 4.15°, P < 0.001). There was no significant difference for JOA score and NDI at follow-up between patients with high-grade and low-grade PO (JOA, 16.2 ± 1.1 vs. 16.8 ± 0.9, P = 0.489; NDI, 8.9 ± 6.1 vs. 8.0 ± 7.3, P = 0.317). CONCLUSION: High-grade PO was observed in the areas of the Luschka joints at the operative level after CDA, which was difficult to observe using X-ray plain film. The PO formation at adjacent segments was not significant.