The safety and accuracy of robot-assisted pedicle screw internal fixation for spine disease: a meta-analysis

Current status and prospects of robot-assisted spine surgery

INTRODUCTION

Traditional spine surgery is frequently impeded by a number of challenges, including the complexity of the underlying anatomy, the depth of the surgical locations, and the limited visibility. These factors can collectively result in prolonged operation times and a reduction in the precision. The advent of robot-assisted spine surgery has brought about a transformative solution, particularly in the context of screw placement. Robot-assisted spine surgery has the potential to enhance accuracy and safety while minimizing soft tissue damage.

AREAS COVERED

This article presents a review of the current state of robot systems in spine surgery. The principal advantages of robot-assisted technology include high precision in screw placement, robust imaging capabilities, reduced surgeon fatigue, and the potential for remote operation, thereby addressing disparities in healthcare access. Clinical studies indicate that robot-assisted techniques significantly improve the accuracy of screw placement and may reduce the incidence of postoperative complications. Challenges such as cost, technology limitations, and the need for comprehensive clinical guidelines persist.

EXPERT OPINION

It is anticipated that future advancements in surgical navigation, artificial intelligence integration and the expansion of robot functions will further enhance the efficacy of robot-assisted spine surgery, with the potential to improve patient outcomes and facilitate broader adoption in clinical practice.

Advancing robot-guided techniques in lumbar spine surgery: a systematic review and meta-analysis

BACKGROUND

Lumbar spine surgery is a crucial intervention for addressing spinal injuries or conditions affecting the spine, often involving lumbar fusion through pedicle screw (PS) insertion. The precision of PS placement is pivotal in orthopedic surgery. This systematic review compares the accuracy of robot-guided (RG) surgery with free-hand fluoroscopy-guided (FFG), free-hand without fluoroscopy-guided (FHG), and computed tomography image-guided (CTG) techniques for PS insertion.

METHODS

A systematic search of various databases from 1 January 2013 to 30 December 2023 was conducted following PRISMA guidelines. Primary outcomes, including PS insertion accuracy and breach rate, were analyzed using a random-effects model. Risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

The overall accuracy of PS insertion using RG, based on 37 studies involving 3,837 patients and 22,117 PS, is 97.9%, with a breach rate of 0.021. RG demonstrated superior accuracy compared to FHG and CTG, with breach rates of 3.4 and 0.015 respectively for RG versus FHG, and 3.8 and 0.026 for RG versus CTG. Additionally, RG was associated with reduced mean estimated blood loss compared to CTG, indicating improved safety.

CONCLUSIONS

The RG is associated with enhanced accuracy of PS insertion and reduced breach rates over other methods. However, additional randomized controlled trials comparing these modalities are needed for further validation.

PROSPERO REGISTRATION

CRD42023483997.

Robotic-Assisted Versus Fluoroscopic-Guided Surgery on the Accuracy of Spine Pedicle Screw Placement: A Systematic Review and Meta-Analysis

Spinal fusion is a common method by which surgeons decrease instability and deformity of the spinal segment targeted. Pedicle screws are vital tools in fusion surgeries and advancements in technology have introduced several modalities of screw placement. Our objective was to evaluate the accuracy of pedicle screw placement in robot-assisted (RA) versus fluoroscopic-guided (FG) techniques. The PubMed and Cochrane Library databases were systematically reviewed from January 2007 through to August 8, 2022, to identify relevant studies. The accuracy of pedicle screw placement was determined using the Gertzbein-Robbins (GR) classification system. Facet joint violation (FJV), total case radiation dosage, total case radiation time, total operating room (OR) time, and total case blood loss were collected. Twenty-one articles fulfilled the inclusion criteria. Successful screw accuracy (GR Grade A or B) was found to be 1.02 (95% confidence interval: 1.01 - 1.04) times more likely with the RA technique. In defining accuracy solely based on the GR Grade A criteria, screws placed with RA were 1.10 (95% confidence interval: 1.06 - 1.15) times more likely to be accurate. There was no significant difference between the two techniques with respect to blood loss (Hedges' g: 1.16, 95% confidence interval: -0.75 to 3.06) or case radiation time (Hedges' g: -0.34, 95% CI: -1.22 to 0.53). FG techniques were associated with shorter operating room times (Hedges' g: -1.03, 95% confidence interval: -1.76 to -0.31), and higher case radiation dosage (Hedges' g: 1.61, 95% confidence interval: 1.11 to 2.10). This review suggests that RA may slightly increase pedicle screw accuracy and decrease per-case radiation dosage compared to FG techniques. However, total operating times for RA cases are greater than those for FG cases.

Safety and Accuracy of Robot-Assisted Cervical Screw Placement: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to compare the accuracy and safety of robot-assisted (RA) cervical screw placement with conventional freehand (FH) technique.

METHODS

Computer-based searches were conducted on various databases including PubMed, Embase, Cochrane Library, Web of Science, the China Biology Medicine, the China National Knowledge Infrastructure, and Wanfang Database. Inclusion criteria were studies reporting the use of RA techniques for cervical screw placement and providing data on safety and accuracy outcomes. Primary outcome indicators focused on the accuracy of screw placement, while secondary outcome indicators included operative time, intraoperative blood loss, length of hospital stay, complication rate, and radiation dose. Data from eligible studies were extracted and synthesized using a forest plot analysis.

RESULTS

A total of 312 patients (1233 screws) from 6 studies were included, with 148 patients (47.4% with 567 screws) in the RA group. Perfect screw accuracy, as categorized by Gertzbein-Robbins grade A, was significantly superior with RA surgery compared to FH technique. RA screw implantation significantly reduced complication rates, intraoperative blood loss, length of hospitalization, and radiation dose compared to the conventional FH group. However, there was no statistically significant difference in surgery time between the RA and FH groups.

CONCLUSIONS

RA surgery significantly improves the accuracy of cervical screw insertion and offers potential advantages in terms of reduced complications and blood loss, shorter hospital stays, and decreased radiation exposure. However, the impact on operative time remains uncertain. Further high-quality studies, including large-scale randomized controlled trials, are needed to strengthen the evidence base.

Is There a Difference in Screw Accuracy, Robot Time Per Screw, Robot Abandonment, and Radiation Exposure Between the Mazor X and the Renaissance? A Propensity-Matched Analysis of 1179 Robot-Assisted Screws

STUDY DESIGN

Prospective single-cohort analysis.

OBJECTIVES

To compare the outcomes/complications of 2 robotic systems for spine surgery.

METHODS

Adult patients (≥18-years-old) who underwent robot-assisted spine surgery from 2016-2019 were assessed. A propensity score matching (PSM) algorithm was used to match Mazor X to Renaissance cases. Preoperative CT scan for planning and an intraoperative O-arm for screw evaluation were preformed. Outcomes included screw accuracy, robot time/screw, robot abandonment, and radiation. Screw accuracy was measured using Vitrea Core software by 2 orthopedic surgeons. Screw breach was measured according to the Gertzbein/Robbins classification.

RESULTS

After PSA, a total of 65 patients (Renaissance: 22 vs. X: 43) were included. Patient/operative factors were similar between robot systems (P > .05). The pedicle screw accuracy was similar between robots (Renaissance: 1.1%% vs. X: 1.3%, P = .786); however, the S2AI screw breach rate was significantly lower for the X (Renaissance: 9.5% vs. X: 1.2%, P = .025). Robot time per screw was not statistically different (Renaissance: 4.6 minutes vs. X: 3.9 minutes, P = .246). The X was more reliable with an abandonment rate of 2.3% vs. Renaissance:22.7%, P = .007. Radiation exposure were not different between robot systems. Non-robot related complications including dural tear, loss of motor/sensory function, and blood transfusion were similar between robot systems.

CONCLUSION

This is the first comparative analyses of screw accuracy, robot time/screw, robot abandonment, and radiation exposure between the Mazor X and Renaissance systems. There are substantial improvements in the X robot, particularly in the perioperative planning processes, which likely contribute to the X's superiority in S2AI screw accuracy by nearly 8-fold and robot reliability by nearly 10-fold.

Detection of Common Anatomical Landmarks and Vertical Trajectories for Freehand Pedicle Screw Placement

OBJECTIVE

It is clinically important for pedicle screws to be placed quickly and accurately. Misplacement of pedicle screws results in various complications. However, the incidence of complications varies greatly due to the different professional titles of physicians and surgical experience. Therefore, physicians must minimize pedicle screw dislocation. This study aims to compare the three nail placement methods in this study, and explore which method is the best for determining the anatomical landmarks and vertical trajectories.

METHODS

This study involved 70 patients with moderate idiopathic scoliosis who had undergone deformity correction surgery between 2018 and 2021. Two spine surgeons used three techniques (preoperative computed tomography scan [CTS], visual inspection-X-freehand [XFH], and intraoperative detection [ID] of anatomical landmarks) to locate pedicle screws. The techniques used include visual inspection for 287 screws in 21 patients, preoperative planning for 346 screws in 26 patients, and intraoperative probing for 309 screws in 23 patients. Observers assessed screw conditions based on intraoperative CT scans (Grade A, B, C, D).

RESULTS

There were no significant differences between the three groups in terms of age, sex, and degree of deformity. We found that 68.64% of screws in the XFH group, 67.63% in the CTS group, and 77.99% in the ID group were placed within the pedicle margins (grade A). On the other hand, 6.27% of screws in the XFH group, 4.33% in the CTS group, and 6.15% in the ID group were considered misplaced (grades C and D). The results show that the total amount of upper thoracic pedicle screws was fewer, meanwhile their placement accuracy was lower. The three methods used in this study had similar accuracy in intermediate physicians (P > 0.05). Compared with intermediate physicians, the placement accuracy of three techniques in senior physicians was higher. The intraoperative detection group was better than the other two groups in the good rate and accuracy of nail placement (P < 0.05).

CONCLUSION

Intraoperative common anatomical landmarks and vertical trajectories were beneficial to patients with moderate idiopathic scoliosis undergoing surgery. It is an optimal method for clinical application.

Clinical application of spinal robot in cervical spine surgery: safety and accuracy of posterior pedicle screw placement in comparison with conventional freehand methods

The novel robot-assisted (RA) technique has been utilized increasingly to improve the accuracy of cervical pedicle screw placement. Although the clinical application of the RA technique has been investigated in several case series and comparative studies, the superiority and safety of RA over conventional freehand (FH) methods remain controversial. Meanwhile, the intra-pedicular accuracy of the two methods has not been compared for patients with cervical traumatic conditions. This study aimed to compare the rate and risk factors of intra-pedicular accuracy of RA versus the conventional FH approach for posterior pedicle screw placement in cervical traumatic diseases. A total of 52 patients with cervical traumatic diseases who received cervical screw placement using RA (26 patients) and FH (26 patients) techniques were retrospectively included. The primary outcome was the intra-pedicular accuracy of cervical pedicle screw placement according to the Gertzbin-Robbins scale. Secondary outcome parameters included surgical time, intraoperative blood loss, postoperative drainage, postoperative hospital stay, and complications. Moreover, the risk factors that possibly affected intra-pedicular accuracy were assessed using univariate analyses. Out of 52 screws inserted using the RA method, 43 screws (82.7%) were classified as grade A, with the remaining 7 (13.5%) and 2 (3.8%) screws classified as grades B and C. In the FH cohort, 60.8% of the 79 screws were graded A, with the remaining screws graded B (21, 26.6%), C (8, 10.1%), and D (2, 2.5%). The RA technique showed a significantly higher rate of optimal intra-pedicular accuracy than the FH method (P = 0.008), but there was no significant difference between the two groups in terms of clinically acceptable accuracy (P = 0.161). Besides, the RA technique showed remarkably longer surgery time, less postoperative drainage, shorter postoperative hospital stay, and equivalent intraoperative blood loss and complications than the FH technique. Furthermore, the univariate analyses showed that severe obliquity of the lateral atlantoaxial joint in the coronal plane (P = 0.003) and shorter width of the lateral mass at the inferior margin of the posterior arch (P = 0.014) were risk factors related to the inaccuracy of C1 screw placement. The diagnosis of HRVA (P < 0.001), severe obliquity of the lateral atlantoaxial joint in the coronal plane (P < 0.001), short pedicle width (P < 0.001), and short pedicle height (P < 0.001) were risk factors related to the inaccuracy of C2 screw placement. RA cervical pedicle screw placement was associated with a higher rate of optimal intra-pedicular accuracy to the FH technique for patients with cervical traumatic conditions. The severe obliquity of the lateral atlantoaxial joint in the coronal plane independently contributed to high rates of the inaccuracy of C1 and C2 screw placements. RA pedicle screw placement is safe and useful for cervical traumatic surgery.

A Comparison of Percutaneous Pedicle Screw Accuracy Between Robotic Navigation and Novel Fluoroscopy-Based Instrument Tracking for Patients Undergoing Instrumented Thoracolumbar Surgery

BACKGROUND

The accuracy of pedicle screws placed with instrument tracking and robotic navigation are individually comparable or superior to placement using standard fluoroscopy, however head-to-head comparisons between these adjuncts in a similar surgical population have yet to be performed.

METHODS

Consecutive patients undergoing percutaneous thoracic and lumbosacral spinal instrumentation were retrospectively enrolled. Instrumentation was performed using either fluoroscopy-based instrument tracking system (TrackX, TrackX Technologies) or robotic-navigation (ExcelsiusGPS, Globus Medical). Postinstrumentation computed tomography scans were graded for breach according to the Gertzbein-Robbins scale, with "acceptable" screws deemed as Grade A or B and "unacceptable" screws deemed as Grades C through E. Accuracy data was compared between both instrumentation modalities.

RESULTS

Fifty-three patients, comprising a total of 250 screws (167 robot, 83 instrument tracking) were included. The overall accuracy between both modalities was similar, with 96.4% and 97.6% of screws with acceptable accuracy between instrument tracking and robotic navigation, respectively (I-squared 0.30, df = 1, P = 0.58). Between instrument tracking and robotic navigation, 92.8% and 95.8% of screws received Grade A, 3.6% and 1.8% a Grade B, 1.2% and 1.2% a Grade C, 1.2% and 0.6% a Grade D, and 1.2% and 0.6% a Grade E, respectively. The robot was abandoned intraoperatively in 2 cases due to unrecoverable registration inaccuracy or software failure, leading to abandonment of 8 potential screws (4.8%).

CONCLUSIONS

In a similar patient population, there is a similarly high degree of instrumentation accuracy between fluoroscopy-based instrument tracking and robotic navigation. There is a rare chance for screw breach with either surgical adjunct.

Robotic assistance in lumbar fusion surgery: trends and patterns from 2016-2019

PURPOSE

Robotic-assisted spine surgery is an emerging field that is growing in utilization. Intraoperative robotic surgical units cost upwards of $600,000 for medical facilities to purchase. Despite significant cost barriers, these devices are highly marketable for hospitals and physicians.

METHODS

The Nationwide Inpatient Sample database from 2016 to 2019 was reviewed. Inclusion criteria were patients over 18 years of age who underwent elective lumbar spinal fusion. Trends of robotic-assisted lumbar fusion were examined over time, as well as stratified based on patient and surgical characteristics.

RESULTS

A total of 176,377 patients met the inclusion criteria. The overall rate of robotic-assisted lumbar fusion was 1.2% (2,131/174,246). Patients with private insurance were more likely to receive robotic-assisted lumbar fusion (40.3% vs. 37.5%; p < 0.05). Stratifying by race, whites were more likely to receive robotic-assisted lumbar fusion (84.1% vs. 79.5%; p < 0.05). Patients who underwent robotic-assisted lumbar fusion were significantly more likely to have a diagnosis of spondylolisthesis compared to those that underwent non-robotic-assisted lumbar fusion (25.9% vs. 22.0%; p < 0.05). Patients with lumbar fusion done via the anterior approach were more likely to have robotic-assisted surgery compared to other approaches (25.2% vs. 21.3; p < 0.05). Overall, there was a steady increase in its use over time, with patients who underwent lumbar fusion procedures four times more likely to receive robotic assistance in 2019 compared to 2016 (OR: 4.0; 95% CI: 3.5-4.6; p < 0.0001). Robotic-assisted lumbar fusion was associated with higher inpatient costs ($170,036.40 vs. $139,026.10; p < 0.0001) despite having equivalent length of stay (3.31 ± 2.6 vs.3.37 ± 2.6; p = 0.06).

CONCLUSION

Robotic-assisted lumbar fusion is on the rise. Patients who had private insurance, were diagnosed with spondylolisthesis, and who had lumbar fusion via the anterior approach were more likely to undergo lumbar fusion using robotic assistance.

Robot-assisted and augmented reality-assisted spinal instrumentation: a systematic review and meta-analysis of screw accuracy and outcomes over the last decade

OBJECTIVE

The use of technology-enhanced methods in spine surgery has increased immensely over the past decade. Here, the authors present the largest systematic review and meta-analysis to date that specifically addresses patient-centered outcomes, including the risk of inaccurate screw placement and perioperative outcomes in spinal surgeries using robotic instrumentation and/or augmented reality surgical navigation (ARSN).

METHODS

A systematic review of the literature in the PubMed, EMBASE, Web of Science, and Cochrane Library databases spanning the last decade (January 2011-November 2021) was performed to present all clinical studies comparing robot-assisted instrumentation and ARSN with conventional instrumentation techniques in lumbar spine surgery. The authors compared these two technologies as they relate to screw accuracy, estimated blood loss (EBL), intraoperative time, length of stay (LOS), perioperative complications, radiation dose and time, and the rate of reoperation.

RESULTS

A total of 64 studies were analyzed that included 11,113 patients receiving 20,547 screws. Robot-assisted instrumentation was associated with less risk of inaccurate screw placement (p < 0.0001) regardless of control arm approach (freehand, fluoroscopy guided, or navigation guided), fewer reoperations (p < 0.0001), fewer perioperative complications (p < 0.0001), lower EBL (p = 0.0005), decreased LOS (p < 0.0001), and increased intraoperative time (p = 0.0003). ARSN was associated with decreased radiation exposure compared with robotic instrumentation (p = 0.0091) and fluoroscopy-guided (p < 0.0001) techniques.

CONCLUSIONS

Altogether, the pooled data suggest that technology-enhanced thoracolumbar instrumentation is advantageous for both patients and surgeons. As the technology progresses and indications expand, it remains essential to continue investigations of both robotic instrumentation and ARSN to validate meaningful benefit over conventional instrumentation techniques in spine surgery.

Biomechanical Analysis of Different Internal Fixation Combined with Different Bone Grafting for Unstable Thoracolumbar Fractures in the Elderly

This research was developed to accurately evaluate the unstable fractures of thoracolumbar before and after surgery and discuss the treatment timing and methods. Three-dimensional (3D) finite element method was adopted to construct the T₁₂-L₅ segment model of human body. The efficiency of percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP), two commonly used internal fixation procedures, was retrospectively compared. A total of 150 patients with chest fracture who received PKP or PVP surgery in our hospital, and 104 patients with the same symptoms who received conservative treatment were collected and randomly rolled into PVP group (75 cases), PKP group (75 cases), and control group (104 cases). Visual analog scale (VAS) score and Oswestry disability index (ODI) of patients were collected before and after surgery and 2, 12, and 24 months after surgery. Then, the anterior and central height of the patient's cone and the kyphosis angle were calculated by X-ray. Lumbar minimally invasive fusion system and lumbar pedicle screw rod system were established by computer-aided design (CAD), and the biomechanical characteristics were analyzed. The results showed that there was no substantial difference in VAS score and ODI score between PKP and PVP (P > 0.05), but they were higher than those of the control group (P < 0.05). The anterior edge and middle height of vertebra in the two groups were higher than those in control group (P < 0.05), and the increase in PKP group was more substantial (P < 0.05). The kyphosis of the two groups was smaller than that of the control group (P < 0.05), and the decrease of the kyphosis of the PKP group was more substantial (P < 0.05). In summary, the thoracolumbar segment model established by 3D finite element method was an effective model, and it was verified on patients that both PKP and PVP could achieve relatively satisfactory efficacy. The implantation of the new internal fixation system had no obvious effect on the lumbar movement. This work provided a novel idea and method for the treatment of senile thoracolumbar unstable fracture, as well as experimental data of biomechanics for the operation of senile unstable fracture.

Pedicle Screw Placement Using Intraoperative Computed Tomography and Computer-Aided Spinal Navigation Improves Screw Accuracy and Avoids Postoperative Revisions: Single-Center Analysis of 1400 Pedicle Screws

OBJECTIVE

Intraoperative computed tomography and navigation (iCT-Nav) is increasingly used to aid spinal instrumentation. We aimed to document the accuracy and revision rate of pedicle screw placement across many screws placed using iCT-Nav. We also assess patient-level factors predictive of high-grade pedicle breach.

METHODS

Medical records of patients who underwent iCT-Nav pedicle screw placement between 2015 and 2017 at a single center were retrospectively reviewed. Screw placement accuracy was individually assessed for each screw using the 2-mm incremental grading system for pedicle breach. Predictors of high-grade (>2 mm) breach were identified using multiple logistic regression.

RESULTS

In total, 1400 pedicle screws were placed in 208 patients undergoing cervicothoracic (29; 13.9%), thoracic (30; 14.4), thoracolumbar (19; 9.1%) and lumbar (130; 62.5%) surgeries. iCT-Nav afforded high-accuracy screw placement, with 1356 of 1400 screws (96.9%) being placed accurately. In total, 37 pedicle screws (2.64%) were revised intraoperatively during the index surgery across 31 patients, with no subsequent returns to the operating room because of screw malpositioning. After correcting for potential confounders, males were less likely to have a high-grade breach (odds ratio [OR] 0.21; 95% confidence interval [CI] 0.10-0.59, P = 0.003) whereas lateral (OR 6.21; 95% CI 2.47-15.52, P < 0.001) or anterior (OR 5.79; 95% CI2.11-15.88, P = 0.001) breach location were predictive of a high-grade breach.

CONCLUSIONS

iCT-Nav with postinstrumentation intraoperative imaging is associated with a reduced need for costly postoperative return to the operating room for screw revision. In comparison with studies of navigation without iCT where 1.5%-1.7% of patients returned for a second surgery, we report 0 revision surgeries due to screw malpositioning.

Robot-guided versus freehand fluoroscopy-guided minimally invasive transforaminal lumbar interbody fusion: a single-institution, observational, case-control study

OBJECTIVE

The use of robotics in spinal surgery has gained popularity because of its promising accuracy and safety. ROSA is a commonly used surgical robot system for spinal surgery. The aim of this study was to compare outcomes between robot-guided and freehand fluoroscopy-guided instrumentation in minimally invasive surgery (MIS)–transforaminal lumbar interbody fusion (TLIF).

METHODS

This retrospective consecutive series reviewed 224 patients who underwent MIS-TLIF from March 2019 to April 2020 at a single institution. All patients were diagnosed with degenerative pathologies. Of those, 75 patients underwent robot-guided MIS-TLIF, and 149 patients underwent freehand fluoroscopy-guided MIS-TLIF. The incidences of pedicle breach, intraoperative outcomes, postoperative outcomes, and short-term pain control were compared.

RESULTS

The patients who underwent robot-guided surgery had a lower incidence of pedicle breach (0.27% vs 1.75%, p = 0.04) and less operative blood loss (313.7 ± 214.1 mL vs 431.6 ± 529.8 mL, p = 0.019). Nonsignificant differences were observed in operative duration (280.7 ± 98.1 minutes vs 251.4 ± 112.0 minutes, p = 0.056), hospital stay (6.6 ± 3.4 days vs 7.3 ± 4.4 days, p = 0.19), complications (intraoperative, 1.3% vs 1.3%, p = 0.45; postoperative surgery-related, 4.0% vs 4.0%, p = 0.99), and short-term pain control (postoperative day 1, 2.1 ± 1.2 vs 1.8 ± 1.2, p = 0.144; postoperative day 30, 1.2 ± 0.5 vs 1.3 ± 0.7, p = 0.610). A shorter operative duration for 4-level spinal surgery was found in the robot-guided surgery group (388.7 ± 107.3 minutes vs 544.0 ± 128.5 minutes, p = 0.047).

CONCLUSIONS

This retrospective review revealed that patients who underwent robot-guided MIS-TLIF experienced less operative blood loss. They also benefited from a shorter operative duration with higher-level (> 3 levels) spinal surgery. The postoperative outcomes were similar for both robot-guided and freehand fluoroscopy-guided procedures.

The effect of cement augmentation on pedicle screw fixation under various load cases : results from a combined experimental, micro-CT, and micro-finite element analysis

Aims

Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques.

Methods

Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S⁴). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads.

Results

Experimental pull-out strengths were excellently correlated to the µFE pull-out stiffness of the ROI (R² > 0.87) and FV (R² > 0.84) models. No significant difference due to screw design was observed. Cement augmentation increased pull-out stiffness by up to 94% and 48% for L and R screws, respectively, but only increased bending stiffness by up to 6.9% and 1.5%, respectively. Cementing involving only one screw tip resulted in lower stiffness increases in all tested screw designs and loading cases. The stiffening effect of cement augmentation on pull-out and bending stiffness was strongly and negatively correlated to local bone density around the screw (correlation coefficient (R) = -0.95).

Conclusion

This combined experimental, µCT and µFE study showed that regional analyses may be sufficient to predict fixation strength in pull-out and that full analyses could show that cement augmentation around pedicle screws increased fixation stiffness in both pull-out and bending, especially for low-density bone.

Cite this article: Bone Joint Res 2021;10(12):797–806.

Computer-assisted cannulated screw internal fixation versus conventional cannulated screw internal fixation for femoral neck fractures: a systematic review and meta-analysis

Objective

To compare the effects between computer-assisted and traditional cannulated screw internal fixation on treating femoral neck fracture.

Methods

The search was conducted in Embase, Pubmed, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI) and Wanfang Database from the beginning to August 2020. RevMan5.4 software, which was provided by the International Cochrane Group, was used for the meta-analysis comparing the differences in operation time, intraoperative bleeding volume, fluoroscopy frequency, fracture healing time, total drilling times, Harris score, fracture healing rate, and femoral head necrosis rate between computer-assisted and traditional methods groups.

Results

A total of 1028 patients were included in 16 studies. Primary outcome indicators: Compared with the traditional method group, the computer-assisted group had less operative time (2RCTs, P < 0.00001; 8 non-RCTs, P = 0.009; Overall, P < 0.00001), intraoperative bleeding (1 RCTs, P < 0.00001; 9non-RCTs, P < 0.00001; Overall, P < 0.00001), femoral head necrosis rate (1 RCT, P = 0.11;7 non-RCTs, P = 0.09; Overall, P = 0.02) and higher Harris scores (1 RCT, P < 0.0001; 9 non-RCTs, P = 0.0002; Overall, P < 0.0001), and there were no significant differences in fracture healing rate between the two groups (5 non-RCTs, P = 0.17). Secondary outcomes indicators: The computer-assisted group had a lower frequency of intraoperative fluoroscopy and total number of drills compared with the traditional method group, while there was no significant difference in fracture healing time.

Conclusion

Compared with the traditional hollow screw internal fixation on the treatment of femoral neck fracture, computer-assisted percutaneous cannulated screw fixation can shorten the operation time and improve the operation efficiency and reduce the X-ray injury of medical staff and help patients obtain a better prognosis. Therefore, computer-assisted percutaneous cannulated screw fixation is a better choice for the treatment of femoral neck fracture.

Study registration PROSPERO registration number CRD42020214493.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02806-7.

Spine Image Guidance and Robotics: Exposure, Education, Training, and the Learning Curve

The use of intraoperative robotics and imaging for spine surgery has been shown to be safe, efficacious, and beneficial to patients, offering accurate placement of instrumentation, decreased operative time and blood loss, and improved postoperative outcomes. Despite these proven benefits, it has yet to be uniformly adopted. One of the major barriers for universal adoption of intraoperative robotics is the learning curve for this complex technology, in conjunction with a lack of formalized training. These same obstacles for universal adoption were faced in the introduction of surgical technology in other disciplines, and the use of this technology has become the standard of care in some of those specialties. Part of the success and widespread implementation of prior novel technology was the introduction of formalized training systems, which are currently lacking in advanced spine surgical technology. Therefore, the future success of intraoperative robotics and imaging for spine surgery depends on the creation of a formalized training system. We detail the best techniques for surgical pedagogy, as well as propose a comprehensive curriculum.

Global Research Trends in Robotic Applications in Spinal Medicine: A Systematic Bibliometric Analysis

OBJECTIVE

We systematically evaluated the global research trends in robotic application on the spine through bibliometric analysis and mapping knowledge domains.

METHODS

A systematic literature search was performed of the PubMed and Web of Science, including the Science Citation Index Expanded, databases. The number, countries, journals, and authors of the publications, total citations, average publication year, and institution sources were analyzed using Microsoft Excel, the Online Analysis Platform of Bibliometrics, and VOSviewer. The hotspots were analyzed and visualized using VOSviewer.

RESULTS

We identified a total of 2135 publications. The United States ranked first in the number of publications (n = 824; 38.63%) and frequency of citations (n = 29,075). Northwestern University had the highest number of publications (n = 67) and Harvard University the highest number of citations (n = 4198). The Journal of NeuroEngineering and Rehabilitation published the largest number of reports (n = 73), and the most frequently cited journal was Nature (n = 3844 citations). The research hotspots were divided into 3 categories analyzed by VOSviewer: rehabilitation, basic science, and surgery. According to the average publication year, the most recent hotspot was radiation exposure, and the earliest hotspot was radiosurgery.

CONCLUSIONS

The number of studies of robotic application on the spine has continued to increase. The United States was the greatest contributor to robotic applications on the spine. Robot-assisted rehabilitation for neurological and orthopedic lesions is still a major research hotspot. The range of robotic applications on the spine has expanded from assisted rehabilitation to assisted rehabilitation and surgery.

A method of 3D-3D multi-stage non-rigid registration of the spine based on binocular structured light

BACKGROUND

Intraoperative deformation and radiation are common problems in spinal surgery. A three-dimensional multi-stage dynamic iterative non-rigid registration method of the spine based on binocular structured light is proposed in this paper to overcome these problems.

METHOD

The problem of intraoperative radiation in traditional X-ray and CT is overcome by using binocular structured light. A three-dimensional spinal mask based on binary code is designed to reduce the influence of non-interested regions on the operation. Principal component analysis (PCA) algorithm is used to complete the rough registration between the preoperative CT model of the spine and the reconstructed surface of the intraoperative structured light. A new framework of multi-stage dynamic iterative non-rigid registration of the spine is proposed. The Iterative Closest Point (ICP) algorithm based on bidirectional selection is proposed to complete the single-stage registration of the spine. Then the multi-stage dynamic iterative registration of the spine is completed to solve the problem of large registration error caused by the deformation of the spine.

RESULTS

The method proposed in this paper is compared with traditional registration methods, and its application is verified experimentally. The results show that the registration accuracy and time of the proposed method are 0 . 51 ± 0 . 31  mm and 5 . 21 ± 0 . 23  s, respectively. The accuracy of the method is 81.5% and 78.2% higher than that of the contour method and the method of marker points, respectively.

CONCLUSIONS

The method can effectively avoid intraoperative radiation, reduce the registration error caused by the deformation of the spine, and has a high practicability.