Guideline for Thoracolumbar Pedicle Screw Placement Assisted by Orthopaedic Surgical Robot

Accurate placement of thoracolumbar pedicle screws using a handheld iOS-based navigation device: a prospective intra-patient agreement study

BACKGROUND

Accurate pedicle screw placement is a challenge with reported misplacement rates of 10% and higher. A handheld navigation device (HND) may provide accuracy equal to CT-based navigation (CT-Nav) but without the cost and complexity.

OBJECTIVE

To study the accuracy of a handheld navigation device for pedicle screw placement.

STUDY DESIGN

This prospective cross-sectional study with consistently applied reference standard enrolled 20 patients undergoing 92 pedicle screw placements.

PATIENTS

Patients who underwent pedicle screw placement between May 2022 and September 2022.

OUTCOME MEASURES

Pedicle screw placement accuracy per Gertzbein-Robbins.

METHODS

Once the screw pilot hole was established, the proposed trajectory of the HND was compared with that proposed by CT-Nav. Postoperatively, screw accuracy was graded according to Gertzbein-Robbins by a blinded radiologist based on CT scans. Accuracy was compared between the two systems and published control for fluoroscopy assisted and CT-Nav placement using Bayesian posterior distribution.

RESULTS

The trajectory proposed by the HND and CT-Nav were in agreement in 98.9% (95% Exact CI; 94.09%-99.97%). The HND accuracy was 98.9% with 91 screws rated "A" and 1 rated "C". Non-inferiority to fluoroscopic placement was achieved because the one-sided normal-approximation 95% CI Lower Bound (LB) of 95.3% is greater than the Performance Goal (PG) of 83.4%. Post-hoc analysis demonstrated that the probability of superiority of the HND relative to the historical accuracy rate of 91.5% for fluoroscopy assisted procedures is >0.999 and that the HND's accuracy rate is within 4.5% of CT-Nav of 95.5% is >0.999. No adverse events or intra-operative complications associated with HND were observed. There was 1 (1.1%) intra-operative repositioning and no re-operations for any reason.

CONCLUSIONS

The accuracy rate of the HND was 98.9%, and the proposed trajectory matched with CT-Nav in 98.9% of the time. This is superior to the historical published accuracy rate for fluoroscopy-assisted procedures and equivalent to the historical published accuracy rate for CT-Nav.

CLINICAL TRIAL REGISTRATION NUMBER

Dutch trial register NL74268.058.20.

Clinical Outcome Analysis of Robot-Assisted Pedicle Screw Insertion in the Treatment of Ankylosing Spondylitis Complicated with Spinal Fractures

BACKGROUND

Vague spinal anatomical landmarks in patients with ankylosing spondylitis (AS) make intraoperative insertion of pedicle screws difficult under direct vision. Currently, the clinical outcome is significantly improved with robot guidance. This study aims to explore the efficacy of robot-assisted pedicle screw insertion in treating AS combined with spinal fractures.

METHODS

Forty patients (341 screws) who underwent pedicle screw insertion with AS complicated with spinal fractures were included. According to different surgical methods, 16 patients (135 screws) were classified into the robot group and 24 (206 screws) into the free-hand group. Intraoperative blood loss, operative duration, and adverse events were compared between the 2 groups. Gertzbein and Robbins classification was used to classify the accuracy of screw position. Clinical outcomes were evaluated by Visual Analog Scale, Japanese Orthopedic Association, and Oswestry Disability Index.

RESULTS

No statistically significant differences between baseline data of the groups. The difference in the blood loss between groups wasn't significant, nor was the operative duration. No severe adverse events related to pedicle screw insertion were reported in either group. Notably, the accuracy of screw insertion was significantly higher in the robot group (129/135) than in the free-hand group (182/206). The lateral perforation prevalence didn't differ among groups. Visual Analog Scale in the third month postoperatively was lower in the robot group than in the free-hand group, with a significant difference.

CONCLUSIONS

The study demonstrates statistically superior accuracy and surgical outcome of robot-assisted pedicle screw insertion in the treatment of AS complicated with spinal fractures compared with the traditional free-hand operation.

Analysis of guide wire displacement in robot-assisted spinal pedicle screw implantation

Robot-assisted pedicle screw placement is prone to guide wire migration, and the related influencing factors have not yet been discussed. Therefore, this study aimed to investigate and analyze the causes of robot-assisted spinal pedicle guide wire displacement and summarize the relevant treatment strategies. The surgical outcomes of 82 patients who underwent robotic-assisted pedicle screw spinal placement at our hospital between July 2022 and June 2023 were retrospectively analyzed. A total of 342 screws were placed in 82 patients; 47 guide wires were offset, 47 guide wires were replaced, and 295 guide wires were not significantly offset, with a first guide wire offset rate of 13.7% and a total guide wire offset rate of 12.1%. Univariate analysis showed that Screw placement level, whether respiration was controlled during guide wire placement, Hu value of CT, the position of needle insertion point, and operation time had a significant effect on guide wire deviation (P < 0.05). Multivariate logistic regression analysis showed that the inclusion of screw placement segments, whether breathing was controlled during guide wire placement, and Hu value of CT had a significant effect on guide wire offset (P < 0.05). Whether the guide wire was offset had no significant effect on the accuracy of subsequent pedicle screw implantation (P > 0.05). The level of screw placement, whether breathing was controlled during guide wire placement, and Hu value of CT were independent risk factors for guide wire deviation. When causing an excursion, screw orientation can be adjusted during intraoperative screw placement, and guide wire excursion has no significant impact on the accuracy of subsequent pedicle screw placement.

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.

Minimally invasive percutaneous screw internal fixation under robot navigation for the treatment of a hamate bone fracture

PURPOSE

Hamate fractures are rare fractures of the wrist and there is still no consensus on the optimal treatment for these fractures, especially hook of hamate fractures. Herein, the authors present a case study of a series of patients who were treated with closed reduction and minimally invasive percutaneous fixation under robot navigation.

METHODS

This retrospective study reviewed 14 patients who had nondisplaced or minimally displaced hamate fractures on computerized tomography images and were treated using the treatment in our centre from November 1, 2019, to October 31, 2022. At the final follow-up, the flexion-extension and radial-ulnar range of motion of the wrist were measured, and the grip strength and pinch strength were measured. The pain of the wrist was assessed using the visual analogue scale (VAS). The Mayo wrist score reflected the recovery of the wrist.

RESULTS

The mean total operative duration was 40.1 min. All the fractures showed union at a mean of 3.0 months. At a mean follow-up of 23.3 months (range 6-36 months), the mean VAS score was 0.7, the average Mayo wrist score was 95, and the mean pinch strength and grip strength were 11.3 and 38.7 kg, respectively. The flexion-extension arc was 138.3°, the mean radial and ulnar deviation arc was 63.8°, and the mean pronation-supination arc was 172.3°. And the time of return to the original occupation was mean 4 months (3~6 months). There were no complications, such as infection or nerve paralysis.

CONCLUSIONS

This study suggests that nondisplaced or minimally displaced hamate hook fractures can be successfully treated by closed reduction and internal fixation with a headless compression screw with the assistance of robot navigation, and the small fragment of fracture can be accurately fixed with minimal iatrogenic injury.

Unique Procedure to Remove Pedicle Screw without Compatible Instrumentation: Case Report and Review of Literature

Introduction

As the number of patients undergoing spine fixation has increased, the requirement for revision surgery has also increased. Difficulty faced while doing revision surgery is mostly in removing polyaxial pedicle screws, especially if we do not have the desired instrumentation.

Case Report

A 55-year-old patient previously operated for D12 fracture presented to us with implant failure due to backing out of pedicle screws. Compatible instrumentation to remove the implant was not available as even the cap screw could not be removed due to screwdriver mismatch. Hence, we had to design our own method to address the problem which we did successfully. At present, the patient is on our regular follow-up, is pain free, is able to walk without support, and has not reported any new complaints.

Conclusion

Method used in our case simplifies and accelerates the screw removal process and provides guidance to any surgeon who faces a similar problem.

Supraspinous ligament arc tangent guided freehand thoracic pedicle screw insertion technique: high parallelism between screws and upper endplate

Research objective

To propose a technique for placing pedicle screws in the thoracic spine using the Supraspinous ligament Arc Tangent (SLAT) as a guide to increase the safety and stability of screw placement.

Content and methods

A retrospective analysis of postoperative anteroposterior and lateral x-ray images was performed for 118 patients with thoracic spine diseases who received conventional freehand technique from January 2016 to May 2020 and SLAT-guided technique since June 2020 to present. The diagnoses included thoracic spinal stenosis, deformity, fractures, infections, and tumors. The angle between the screw and the upper endplate was categorized as grade 1 (0°-5°), grade 2 (5°-10°), and grade 3 (>10°). Three surgeons with more than 10 years of experience in spinal surgery measured the angle between the screw and the upper endplate in the lateral view. Chi-square test was used for statistical analysis, and p < 0.05 was considered statistically significant.

Results

A total of 1315 pedicle screws were placed from T1 to T12 in all patients. In the conventional freehand technique group, 549 screws were grade 1, 35 screws were grade 2, and 23 screws were grade 3. In the SLAT-guided freehand technique group, 685 screws were grade 1, 15 screws were grade 2, and 8 screws were grade 3. The data of each group was p < 0.05 by Chi-squared test, which was statistically significant, indicating that the SLAT-guided freehand technique resulted in a higher rate of parallelism between the screws and the upper endplate. All patients underwent intraoperative neurophysiological monitoring, immediate postoperative neurological examination, postoperative x-ray examination, and assess the eventual recovery. The screws were safe and stable, and no complications related to pedicle screw placement were found.

Conclusion

The SLAT-guided freehand technique for placing pedicle screws in the thoracic spine can achieve a higher rate of screw-upper endplate parallelism, making screw placement safer and more accurate. Our method provides a convenient and reliable technique for most spinal surgeons, allowing for increased accuracy and safety with less fluoroscopic guidance.

Sonification as a reliable alternative to conventional visual surgical navigation

Despite the undeniable advantages of image-guided surgical assistance systems in terms of accuracy, such systems have not yet fully met surgeons' needs or expectations regarding usability, time efficiency, and their integration into the surgical workflow. On the other hand, perceptual studies have shown that presenting independent but causally correlated information via multimodal feedback involving different sensory modalities can improve task performance. This article investigates an alternative method for computer-assisted surgical navigation, introduces a novel four-DOF sonification methodology for navigated pedicle screw placement, and discusses advanced solutions based on multisensory feedback. The proposed method comprises a novel four-DOF sonification solution for alignment tasks in four degrees of freedom based on frequency modulation synthesis. We compared the resulting accuracy and execution time of the proposed sonification method with visual navigation, which is currently considered the state of the art. We conducted a phantom study in which 17 surgeons executed the pedicle screw placement task in the lumbar spine, guided by either the proposed sonification-based or the traditional visual navigation method. The results demonstrated that the proposed method is as accurate as the state of the art while decreasing the surgeon's need to focus on visual navigation displays instead of the natural focus on surgical tools and targeted anatomy during task execution.

Accuracy Evaluation of a Novel Spinal Robotic System for Autonomous Laminectomy in Thoracic and Lumbar Vertebrae: A Cadaveric Study

BACKGROUND

The main function of robots in spine surgery is to assist with pedicle screw placement. Laminectomy, which is as important as pedicle screw placement, lacks a mature robot-assisted system. The aims of this study were to introduce the first autonomous laminectomy robot, to explore the feasibility of autonomous robotic laminectomy, and to validate its accuracy using a cadaveric model.

METHODS

Forty vertebrae from 4 cadavers were included in the study; 7 thoracic and 3 lumbar vertebrae were randomly selected in each cadaver. The surgeon was able to plan the laminectomy path based on computed tomographic (CT) data before the surgical procedure. The robot performed the laminectomy autonomously, and a postoperative CT scan was made. The deviation of each cutting plane from the plan was quantitatively analyzed, and the accuracy and safety were qualitatively evaluated. The time required for the laminectomy was also recorded.

RESULTS

Cuts were performed in 80 laminectomy planes (56 for thoracic vertebrae and 24 for lumbar vertebrae). The mean time for 1-sided laminectomy was 333.59 ± 116.49 seconds, which was shorter for thoracic vertebrae (284.41 ± 66.04 seconds) than lumbar vertebrae (448.33 ± 128.65 seconds) (p < 0.001). The mean time for single-level total laminectomy was 814.05 ± 302.23 seconds, which was also shorter for thoracic vertebrae (690.46 ± 165.74 seconds) than lumbar vertebrae (1,102.42 ± 356.13 seconds) (p = 0.002). The mean deviation of the cutting plane from the plan was 0.67 ± 0.30 mm for the most superior cutting point and 0.73 ± 0.31 mm for the most inferior point. There were no significant differences in the deviation between thoracic vertebrae (0.66 ± 0.26 mm) and lumbar vertebrae (0.67 ± 0.38 mm) at the superior cutting point (p = 0.908) and between thoracic vertebrae (0.72 ± 0.30 mm) and lumbar vertebrae (0.73 ± 0.33 mm) at the inferior cutting point (p = 0.923). In the qualitative analysis of the accuracy of the 80 laminectomy planes, 66 (83%) were classified as grade A, 14 (18%) were grade B, and none was grade C. In the safety analysis, 65 planes (81%) were considered safe and the safety of the other 15 planes (19%) was considered uncertain.

CONCLUSIONS

The results confirmed the accuracy of this robotic system, supporting its use for laminectomy of thoracolumbar vertebrae.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

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.

Discussion on the possibility of multi-layer intelligent technologies to achieve the best recover of musculoskeletal injuries: Smart materials, variable structures, and intelligent therapeutic planning

Although intelligent technologies has facilitated the development of precise orthopaedic, simple internal fixation, ligament reconstruction or arthroplasty can only relieve pain of patients in short-term. To achieve the best recover of musculoskeletal injuries, three bottlenecks must be broken through, which includes scientific path planning, bioactive implants and personalized surgical channels building. As scientific surgical path can be planned and built by through AI technology, 4D printing technology can make more bioactive implants be manufactured, and variable structures can establish personalized channels precisely, it is possible to achieve satisfied and effective musculoskeletal injury recovery with the progress of multi-layer intelligent technologies (MLIT).

AR-Supported Supervision of Conditional Autonomous Robots: Considerations for Pedicle Screw Placement in the Future

Robotic assistance is applied in orthopedic interventions for pedicle screw placement (PSP). While current robots do not act autonomously, they are expected to have higher autonomy under surgeon supervision in the mid-term. Augmented reality (AR) is promising to support this supervision and to enable human–robot interaction (HRI). To outline a futuristic scenario for robotic PSP, the current workflow was analyzed through literature review and expert discussion. Based on this, a hypothetical workflow of the intervention was developed, which additionally contains the analysis of the necessary information exchange between human and robot. A video see-through AR prototype was designed and implemented. A robotic arm with an orthopedic drill mock-up simulated the robotic assistance. The AR prototype included a user interface to enable HRI. The interface provides data to facilitate understanding of the robot’s ”intentions”, e.g., patient-specific CT images, the current workflow phase, or the next planned robot motion. Two-dimensional and three-dimensional visualization illustrated patient-specific medical data and the drilling process. The findings of this work contribute a valuable approach in terms of addressing future clinical needs and highlighting the importance of AR support for HRI.

Comparison of accuracy and safety between second-generation TiRobot-assisted and free-hand thoracolumbar pedicle screw placement

Background

Robot-assisted spine surgery aims to improve the accuracy of screw placement. We compared the accuracy and safety between a novel robot and free hand in thoracolumbar pedicle screw placement.

Methods

Eighty patients scheduled to undergo robot-assisted (40 patients) and free-hand (40 patients) pedicle screw placement were included. The patients’ demographic characteristics, radiographic accuracy, and perioperative outcomes were compared. The accuracy of screw placement was based on cortical violation and screw deviation. Safety outcomes mainly included operative time, blood loss, revision, and complications.

Results

A total of 178 and 172 screws were placed in the robot-assisted and free-hand groups, respectively. The rate of perfect screw position (grade A) was higher in the robot-assisted group than in the free-hand group (91.0% vs. 75.6%; P < 0.001). The rate of clinically acceptable screw position (grades A and B) was also higher in the robot-assisted group than in the free-hand group (99.4% vs. 90.1%; P < 0.001). The robot-assisted group had significantly lower screw deviation than the free-hand group [1.46 (0.94, 1.95) mm vs. 2.48 (1.09, 3.74) mm, P < 0.001]. There was no robot abandonment in the robot-assisted group. No revision was required in any of the groups.

Conclusions

Robot-assisted pedicle screw placement is more accurate than free-hand placement. The second-generation TiRobot–assisted thoracolumbar pedicle screw placement is an accurate and safe procedure.

Trial registration retrospectively registered

Robot-Assisted Versus Fluoroscopy-Assisted Kyphoplasty in the Treatment of Osteoporotic Vertebral Compression Fracture: A Retrospective Study

STUDY DESIGN

A retrospective study.

OBJECTIVES

To compare the clinical and radiological outcomes of robot assisted (RA) and fluoroscopy assisted (FA) percutaneous kyphoplasty (PKP) in treating single/double segment osteoporotic vertebral compression fracture (OVCF).

METHODS

Patients with single/double segment OVCF receiving either RA or FA PKP were evaluated retrospectively at our spine center from April 2018 to October 2019. The operation time, fluoroscopy frequency, fluoroscopy exposure time, total radiation dose, visual analogue scale (VAS), local kyphosis angle (LKA), height of fractured vertebra (HFV) and complications were compared between the single/double RA group and the FA group.

RESULTS

A total of 96 cases were included in this study, with 59 cases of single segment OVCF and 37 cases of double segment OVCF. For single/double segment OVCF, both RA and FA PKP could relieve pain and reduce fracture. The RA group showed lower fluoroscopy frequency, shorter fluoroscopy exposure time during operation for surgeons, better correction in LKA and HFV, lower rate of cement leakage, but more fluoroscopy frequency, fluoroscopy exposure time and radiation dose for patients compared with the FA group (P < 0.05), while the single RA group showed longer operation time compared with the FA group (P < 0.05).

CONCLUSIONS

For single/double segment OVCF, RA has more advantages in correcting vertebra fracture, reducing intraoperative radiation exposure for surgeons, and reducing the cement leakage rate, but it increases intraoperative radiation for patients compared with FA PKP. And FA has shorter operation time in treating single segment OVCF than RA PKP.

Minimally-Invasive Assisted Robotic Spine Surgery (MARSS)

Minimally-Invasive robotic spine surgery (MARSS) has expanded the surgeons armamentarium to treat a variety of spinal disorders. In the last decade, robotic developments in spine surgery have improved the safety, accuracy and efficacy of instrumentation placement. Additionally, robotic instruments have been applied to remove tumors in difficult locations while maintaining minimally invasive access. Gross movements by the surgeon are translated into fine, precise movements by the robot. This is exemplified in this chapter with the use of the da Vinci robot to remove apical thoracic tumors. In this chapter, we will review the development, technological advancements, and cases that have been conducted using MARSS to treat spine pathology in a minimally invasive fashion.

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.

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 18^th and 17^th 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.

Motor Bur Milling State Identification via Fast Fourier Transform Analyzing Sound Signal in Cervical Spine Posterior Decompression Surgery

Objectives

To investigate the real‐time sensitive feedback parameter of the motor bur milling state in cervical spine posterior decompression surgery, to possibly improve the safety of cervical spine posterior decompression and robot‐assisted spinal surgeries.

Methods

In this study, the cervical spine of three healthy male and three healthy female pigs were randomly selected. Six porcine cervical spine specimens were fixed to the vibration isolation system. The milling state of the motor bur was defined as the lamina cancellous bone (CA), lamina ventral corticalbone (VCO), and penetrating ventral cortical bone (PVCO). A 5‐mm bur milled the CA and VCO, and a 2‐mm bur milled the VCO and PVCO. A miniature microphone was used to collect the sound signal (SS) of milling lamina which was then extracted using Fast Fourier Transform (FFT). When using 5‐mm and 2‐mm bur to mill, the CA, VCO, and PVCO of each specimen were continuously collected at 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 kHz frequencies for SS magnitudes. The study randomly selected the SS magnitudes of the CA and VCO continuously for 2 s at 1, 2, 3, 4, and 5 kHz frequencies for statistical analyses. When milling the VCO to the PVCO, we randomly collected the SS magnitudes of the VCO for consecutive 2 s and the SS magnitudes of continuous 2 s in the penetrating state at 1, 2, 3, 4, and 5 kHz frequencies for statistical analyses. The independent sample t‐test was used to compare the SS magnitudes of different milling states extracted from the FFT to determine the motor bur milling state.

Results

The SS magnitudes of the CA and VCO of all specimens extracted from the FFT at 1, 2, and 3 kHz were statistically different (P < 0.01); three specimens were not statistically different at a specific FFT‐extracted frequency (first specimen at 5 kHz, SS magnitudes of the CA were [25.94 ± 8.74] × 10⁻³, SS magnitudes of the VCO were [28.67 ± 12.94] × 10⁻³, P = 0.440; second specimen at 4 kHz, SS magnitudes of the CA were [23.79 ± 7.94] × 10⁻³, SS magnitudes of the VCO were [24.78 ± 4.32] × 10⁻³, P = 0.629; and third specimen at 5 kHz, SS magnitudes of the CA were [16.76 ± 6.20] × 10⁻³, SS magnitudes of the VCO were [17.69 ± 6.44] × 10⁻³, P = 0.643).The SS magnitudes of the VCO and PVCO of all the specimens extracted from the FFT at each frequency were statistically different (P < 0.001).

Conclusions

Based on the FFT extraction, the SS magnitudes of the motor bur milling state between the CA and VCO, the VCO and PVCO were significantly different, confirming that the SS is a potential sensitive feedback parameter for identifying the motor bur milling state. This study could improve the safety of cervical spine posterior decompression surgery, especially of robot‐assisted surgeries.

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.

Comparison of Outcomes between Robot-Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion and Oblique Lumbar Interbody Fusion in Single-Level Lumbar Spondylolisthesis

Objective

To compare the safety and effectiveness of robot‐assisted minimally invasive transforaminal lumbar interbody fusion (Mis‐TLIF) and oblique lumbar interbody fusion (OLIF) for the treatment of single‐level lumbar degenerative spondylolisthesis (LDS).

Methods

This is a retrospective study. Between April 2018 and April 2020, a total of 61 patients with single‐level lumbar degenerative spondylolisthesis and treated with robot‐assisted OLIF (28 cases, 16 females, 12 males, mean age 50.4 years) or robot‐assisted Mis‐TLIF (33 cases, 18 females, 15 males, mean age 53.6 years) were enrolled and evaluated. All the pedicle screws were implanted percutaneously assisted by the TiRobot system. Surgical data included the operation time, blood loss, and length of postoperative hospital stay. The clinical and functional outcomes included Oswestry Disability Index (ODI), Visual Analog scores (VAS) for back and leg pain, complication, and patient's satisfaction. Radiographic outcomes include pedicle screw accuracy, fusion status, and disc height. These data were collected before surgery, at 1 week, 3 months, 6 months, and 12 months postoperatively.

Results

There were no significantly different results in preoperative measurement between the two groups. There was significantly less blood loss (142.4 ± 89.4 vs 291.5 ± 72.3 mL, P < 0.01), shorter hospital stays (3.2 ± 1.8 vs 4.2 ± 2.5 days, P < 0.01), and longer operative time (164.9 ± 56.0 vs 121.5 ± 48.2 min, P < 0.01) in OLIF group compared with Mis‐TLIF group. The postoperative VAS scores and ODI scores in both groups were significantly improved compared with preoperative data (P < 0.05). VAS scores for back pain were significantly lower in OLIF group than Mis‐TLIF group at 1 week (2.8 ± 1.2 vs 3.5 ± 1.6, P < 0.05) and 3 months postoperatively (1.6 ± 1.0 vs 2.1 ± 1.1, P < 0.05), but there was no significant difference at further follow‐ups. ODI score was also significantly lower in OLIF group than Mis‐TLIF group at 3 months postoperatively (22.3 ± 10.0 vs 26.1 ± 12.8, P < 0.05). There was no significant difference in the proportion of clinically acceptable screws between the two groups (97.3% vs 96.2%, P = 0.90). At 1 year, the OLIF group had a higher interbody fusion rate compared with Mis‐TLIF group (96.0% vs 87%, P < 0.01). Disc height was significantly higher in the OLIF group than Mis‐TLIF group (12.4 ± 3.2 vs 11.2 ± 1.3 mm, P < 0.01). Satisfaction rates at 1 year exceeded 90% in both groups and there was no significant difference (92.6% for OLIF vs 91.2% for Mis‐TLIF, P = 0.263).

Conclusion

Robot‐assisted OLIF and Mis‐TLIF both have similar good clinical outcomes, but OLIF has the additional benefits of less blood loss, less postoperative hospital stays, higher disc height, and higher fusion rates. Robots are an effective tool for minimally invasive spine surgery.

Comparison of accuracy and safety between robot-assisted and conventional fluoroscope assisted placement of pedicle screws in thoracolumbar spine: A meta-analysis

OBJECTIVE

The purpose of this systematic review and meta-analysis is to explore the screw positioning accuracy, complications related to pedicle screw implantation, revision rate and radiation exposure between robot screw placement and traditional fluoroscopic screw placement.

METHODS

We searched several databases, including CNKI, Wanfang database, cqvip datebase, PubMed, Cochrane library and EMBASE, to identify articles that might meet the criteria. Meta-analysis was performed using Revman 5.3 software.

RESULTS

A total of 13 randomized controlled trial were included. The results showed that the pedicle screw accuracy of the robot assisted group was significantly better than that of the conventional freehand (FH) group (OR = 3.5, 95% confidence interval [CI] [2.75,4.45], P < .0001). There was no significant difference in the complications caused by pedicle screw implantation between the robot-assisted group and the conventional FH group [OR = 0.39, 95%CI (0.10,1.48), P = .17]. The rate of facet joint invasion in the robot-assisted group was significantly lower than that in the conventional FH group (OR = 0.06, 95%CI [0.01,0.29], P = .0006). The revision rate in the robot-assisted group was significantly lower than that in the conventional FH group (OR = 0.19, 95%CI [0.05,0.71], P = 0.0.01). There was no significant difference in the average radiation of pedicle screws implantation between the robot-assisted group and the conventional FH (mean difference = -7.94, 95%CI [-20.18,4.30], P = .20).

CONCLUSION

The robot-assisted group was significantly better than the conventional FH in the accuracy of pedicle screw placement and facet joint invasion rate and revision rate. There was no significant difference in the complication and fluoroscopy time between the two groups.

Thoracolumbar Burst Fractures: A Systematic Review and Meta-Analysis Comparing Posterior-Only Instrumentation Versus Combined Anterior-Posterior Instrumentation

STUDY DESIGN

Meta-analysis.

OBJECTIVE

To compare the clinical, functional, and radiological outcomes of posterior-only versus combined anterior-posterior instrumentation in order to determine the optimal surgical intervention for thoracolumbar burst fractures.

SUMMARY OF BACKGROUND DATA

Unstable thoracolumbar burst fractures warrant surgical intervention to prevent neurological deterioration and progressive kyphosis, which can lead to significant pain and functional morbidity. The available literature remains largely inconclusive in determining the optimal instrumentation strategy.

METHODS

Electronic searches of MEDLINE (1948-May 2020), EMBASE (1947-May 2020), The Cochrane Library (1991-May 2020), and other databases were conducted. Cochrane Collaboration guidelines were used for data extraction and quality assessment. Outcomes of interest were divided into three categories: radiological (degree of postoperative kyphosis correction; loss of kyphosis correction at final follow-up), functional (visual analogue scale [VAS] pain score; Oswestry Disability Index [ODI] score), and clinical (intraoperative blood loss; length of stay [LOS]; operative time; the number and type of postoperative complications).

RESULTS

Four randomized control trials (RCTs) were retrieved, including 145 randomized participants. Seventy-three patients underwent posterior-only instrumentation and 72 underwent combined instrumentation. No significant difference was found in the degree of postoperative kyphosis correction (P = 0.39), VAS (centimeters) at final follow-up (P = 0.67), ODI at final follow-up (P = 0.89) or the number of postoperative complications between the two approaches (P = 0.49). Posterior-only instrumentation was associated with lower blood loss (P < 0.001), operative time (P < 0.001), and LOS (P = 0.01). Combined instrumentation had a lower degree of kyphosis loss at final follow-up (P = 0.001). There was heterogeneity in the duration of follow-up between the included studies (mean follow-up range 24-121 months).

CONCLUSION

The available literature remains largely inconclusive. In order to reliably inform practice in this area, there is a need for large, high-quality, multicenter RCTs with standardized reporting of outcomes, with a particular focus on outcomes relating to patient function and severe complications causing long-term morbidity.Level of Evidence: 2.

Analysis of sagittal curvature and its influencing factors in adolescent idiopathic scoliosis

ABSTRACT

This study aimed to explore the characteristics of changes in the sagittal arrangement of the spine between adolescent patients with idiopathic scoliosis (AIS) and normal adolescents, the risk factors for AIS and the factors affecting the progress of AIS.X-ray images of the full length of the spine in standing position were taken in AIS patients and normal adolescents. Radiographic measurements made at intermediate follow-up included the following:C1 and C2 cervical lordosis and C2 - C7 curvature of cervical lordosis, C2-C7sagittal horizontal distance (C2-C7SagittalVerticalAxis, C2-C7SVA), TS-CL, after thoracic lobe (Thoracic Kyphosis, TK), thoracic lumbar segment Angle (thoracolumbar kyphosis, [TLK]), lumbar lordosis Angle (Lumbar Lordosis, LL), sacral slope Angle (Sacrum Slope, SS), pelvic tilt Angle (Pelvic Tilt, PT), pelvic incidence (PI), L5 Incidence (Lumbar5 Slope (L5S), L5 incidence (Lumbar5 Incidence (L5I), sagittal horizontal distance (CSVA), lower depression Angle of the 2nd cervical spine. The difference of sagittal plane parameters between AIS group and normal adolescent group was compared. To evaluate the progress of AIS, correlation analysis was conducted between diagonal 2 and other parameters. The main risk factors of AIS were determined by binary Logistic analysis.The CSVA of AIS patients was higher than that of healthy adolescents (AIS: 27.64 ± 19.56) mm. Healthy adolescents: (17.74 ± 12.8) mm), L5S (AIS: 19.93°= 7.07° and healthy adolescents: 15.38°= 7.78°, P = .024 < .05), C2 downward sag Angle (AIS: 15.12°= 2.7°;Healthy adolescents: 12.97°= 4.56°); AIS patients had lower TS-CL (AIS: 22.48 ± 6.09 and healthy adolescents: 28.26°= 10.32°), PT (AIS: 10.42°= 4.53° and healthy adolescents: 15.80°=7.68°), (AIS: 41.87°=9.72° and healthy adolescents: 48.75°= 8.22°). The main risk factor for idiopathic scoliosis in adolescents was L5 (OR = 1.239, 95%CI = 1.049-1.463, P = .012 < .05).L5S is a major risk factor for idiopathic scoliosis in adolescents. The larger PI is, the higher the risk of scoliosis progression is. In AIS patients, lumbar lordosis is increased, cervical lordosis is reduced, and even cervical kyphosis occurs.

[A comparative study of robot-assisted and freehand pedicle screw placement in upper thoracic surgery]

Objective

To compare the safety and accuracy of pedicle screw placement assisted by robot system with freehand pedicle screw placement in upper thoracic surgery.

Methods

Between December 2017 and December 2019, 39 cases with upper thoracic pedicle screw internal fixation were included in the study, including 19 cases in robot group (group A, robot assisted pedicle screw placement) and 20 cases in freehand group (group B, freehand pedicle screw placement). There were 104 screws implanted in group A and 108 screws in group B. There was no significant difference in age, gender composition, body mass index, disease type, number of screws implanted, and segmental distribution between the two groups ( P>0.05). The operation time, intraoperative blood loss, and postoperative drainage were recorded and compared between the two groups. CT scan was performed in all patients at 2 days after operation to evaluate the screw accuracy based on the Gertzbein-Robbins grading standard.

Results

The operation time of group A was significantly longer than that in group B ( t=2.759, P=0.009). There was no significant difference in intraoperative blood loss and postoperative drainage between the two groups ( t=-0.796, P=0.431; t=-0.814, P=0.421). At 2 days after operation, according to Gertzbein-Robbins grading standard, the accuracy of pedicle screw implantation in group A were grade A in 94 screws, grade B in 9 screws, and grade C in 1 screw; and in group B were grade A in 72 screws, grade B in 26 screws, grade C in 9 screws, and grade D in 1 screw; the difference between the two groups was significant ( Z=4.257, P=0.000). The accuracy rate of group A was 99.04%, and that of group B was 90.74%, showing significant difference ( χ ²=7.415, P=0.006).

Conclusion

Compared with traditional freehand pedicle screw placement, robot-assisted pedicle screw placement significantly improves the accuracy and safety of screw placement without increasing the bleeding and postoperative drainage.

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

Aims

The aim of this study was to systematically compare the safety and accuracy of robot-assisted (RA) technique with conventional freehand with/without fluoroscopy-assisted (CT) pedicle screw insertion for spine disease.

Methods

A systematic search was performed on PubMed, EMBASE, the Cochrane Library, MEDLINE, China National Knowledge Infrastructure (CNKI), and WANFANG for randomized controlled trials (RCTs) that investigated the safety and accuracy of RA compared with conventional freehand with/without fluoroscopy-assisted pedicle screw insertion for spine disease from 2012 to 2019. This meta-analysis used Mantel-Haenszel or inverse variance method with mixed-effects model for heterogeneity, calculating the odds ratio (OR), mean difference (MD), standardized mean difference (SMD), and 95% confidence intervals (CIs). The results of heterogeneity, subgroup analysis, and risk of bias were analyzed.

Results

Ten RCTs with 713 patients and 3,331 pedicle screws were included. Compared with CT, the accuracy rate of RA was superior in Grade A with statistical significance and Grade A + B without statistical significance. Compared with CT, the operating time of RA was longer. The difference between RA and CT was statistically significant in radiation dose. Proximal facet joint violation occurred less in RA than in CT. The postoperative Oswestry Disability Index (ODI) of RA was smaller than that of CT, and there were some interesting outcomes in our subgroup analysis.

Conclusion

RA technique could be viewed as an accurate and safe pedicle screw implantation method compared to CT. A robotic system equipped with optical intraoperative navigation is superior to CT in accuracy. RA pedicle screw insertion can improve accuracy and maintain stability for some challenging areas.Cite this article: Bone Joint Res 2020;9(10):653-666.

A novel fluoroscopy-based robot system for pedicle screw fixation surgery

BACKGROUND

Robot-assisted pedicle screw insertion has gained popularity in the spinal surgery field. Due to high cost, these spinal robots are not extensively applied in clinical surgeries. Developing an effective robot system with low cost and high clinical acceptability is one of the future trends.

METHODS

We developed a novel fluoroscopy-based robot system for pedicle screw insertion. Four live pigs were conducted with percutaneous pedicle screw insertion. Robot-assisted surgery was performed on the left side of pedicle, while the right opposite side is placed by freehand. The respect accuracy, surgical time and fluoroscopy time were recorded.

RESULTS

Robot-assisted group achieved 100% (23/23) accuracy. The average times (6.4 ± 1.7) for intraoperative fluoroscopy usage per procedure were lesser than freehand group (12.5 ± 3.6), and the surgical time (6.8 ± 2.1 min) per screw was reduced compared with freehand group (12.1 ± 4.8 min).

CONCLUSIONS

Our robot system is cost-effective and feasible for pedicle screw placement. Low economic cost makes it easier for extensive application in primary hospitals.

Telerobotic Spinal Surgery Based on 5G Network: The First 12 Cases

Objective

The purpose of this study was to determine the efficacy and feasibility of 5th generation wireless systems (5G) telerobotic spinal surgery in our first 12 cases.

Methods

A total of 12 patients (5 males, 7 females; age, 23–71 years) with spinal disorders (4 thoracolumbar fractures, 6 lumbar spondylolisthesis, 2 lumbar stenosis) were treated with 5G telerobotic spinal surgery. Sixty-two pedicle screws were implanted.

Results

All patients had substantial relief from their symptoms. Screw placements were classified using Gertzbein-Robbins criteria. There were 59 grade A, 3 grade B. Mean operation time was 142.5 ± 46.7 minutes. Mean guiding wire insertion time was 41.3 ± 9.8 minutes. The deviation between the planned and actual positions was 0.76 ± 0.49 mm. No intraoperative adverse event was found.

Conclusion

5G remote robot-assisted spinal surgery is accurate and reliable. We conclude that 5G telerobotic spinal surgery is both efficacious and feasible for the management of spinal diseases with safety.

Comparison of Superior-Level Facet Joint Violations Between Robot-Assisted Percutaneous Pedicle Screw Placement and Conventional Open Fluoroscopic-Guided Pedicle Screw Placement

Objective

To compare the superior‐level facet joint violations (FJV) between robot‐assisted (RA) percutaneous pedicle screw placement and conventional open fluoroscopic‐guided (FG) pedicle screw placement in a prospective cohort study.

Methods

This was a prospective cohort study without randomization. One‐hundred patients scheduled to undergo RA (n = 50) or FG (n = 50) transforaminal lumbar interbody fusion were included from February 2016 to May 2018. The grade of FJV, the distance between pedicle screws and the corresponding proximal facet joint, and intra‐pedicle accuracy of the top screw were evaluated based on postoperative CT scan. Patient demographics, perioperative outcomes, and radiation exposure were recorded and compared. Perioperative outcomes include surgical time, intraoperative blood loss, postoperative length of stay, conversion, and revision surgeries.

Results

Of the 100 screws in the RA group, 4 violated the proximal facet joint, while 26 of 100 in the FG group had FJV (P = 0.000). In the RA group, 3 and 1 screws were classified as grade 1 and 2, respectively. Of the 26 FJV screws in the FG group, 17 screws were scored as grade 1, 6 screws were grade 2, and 3 screws were grade 3. Significantly more severe FJV were noted in the FG group than in the RA group (P = 0.000). There was a statistically significant difference between RA and FG for overall violation grade (0.05 vs 0.38, P = 0.000). The average distance of pedicle screws from facet joints in the RA group (4.16 ± 2.60 mm) was larger than that in the FG group (1.92 ± 1.55 mm; P = 0.000). For intra‐pedicle accuracy, the rate of perfect screw position was greater in the RA group than in the FG group (85% vs 71%; P = 0.017). No statistically significant difference was found between the clinically acceptable screws between groups (P = 0.279). The radiation dose was higher in the FG group (30.3 ± 11.3 vs 65.3 ± 28.3 μSv; P = 0.000). The operative time in the RA group was significantly longer (184.7 ± 54.3 vs 117.8 ± 36.9 min; P = 0.000).

Conclusions

Compared to the open FG technique, minimally invasive RA spine surgery was associated with fewer proximal facet joint violations, larger facet to screw distance, and higher intra‐pedicle accuracy.

Optimization of virtual and real registration technology based on augmented reality in a surgical navigation system

Background

The traditional navigation interface was intended only for two-dimensional observation by doctors; thus, this interface does not display the total spatial information for the lesion area. Surgical navigation systems have become essential tools that enable for doctors to accurately and safely perform complex operations. The image navigation interface is separated from the operating area, and the doctor needs to switch the field of vision between the screen and the patient’s lesion area. In this paper, augmented reality (AR) technology was applied to spinal surgery to provide more intuitive information to surgeons. The accuracy of virtual and real registration was improved via research on AR technology. During the operation, the doctor could observe the AR image and the true shape of the internal spine through the skin.

Methods

To improve the accuracy of virtual and real registration, a virtual and real registration technique based on an improved identification method and robot-assisted method was proposed. The experimental method was optimized by using the improved identification method. X-ray images were used to verify the effectiveness of the puncture performed by the robot.

Results

The final experimental results show that the average accuracy of the virtual and real registration based on the general identification method was 9.73 ± 0.46 mm (range 8.90–10.23 mm). The average accuracy of the virtual and real registration based on the improved identification method was 3.54 ± 0.13 mm (range 3.36–3.73 mm). Compared with the virtual and real registration based on the general identification method, the accuracy was improved by approximately 65%. The highest accuracy of the virtual and real registration based on the robot-assisted method was 2.39 mm. The accuracy was improved by approximately 28.5% based on the improved identification method.

Conclusion

The experimental results show that the two optimized methods are highly very effective. The proposed AR navigation system has high accuracy and stability. This system may have value in future spinal surgeries.

Robotic navigation during spine surgery

Introduction: Potential complications associated with screw malposition may result in neurological deficits or vascular injuries. Spine surgery has significantly developed under the assistance of technological progress. The advantages of applying robotic technology in spine surgery include the possibility of improving screw accuracy, reducing complications, decreasing fluoroscopy use.Areas covered: We critically evaluated the current literature on the radiographic and clinical outcomes of robotic-assisted spine surgery, including accuracy, radiation exposure, operative time, and complication rates.Expert opinion: Robotic-assisted spine surgery shows promising results and has the potentials for further investigations. The robot-assisted spine surgery is appeared to be more accurate in pedicle screw placement than the free-hand technique. In general, the robot-assisted technique is associated with shorter radiation exposure time but longer operative time than free-hand technique. For higher accuracy of robotic-assisted spine surgery, technical advancement and high-quality researches are needed. Artificial intelligent technology, decompression function, and higher accuracy are the directions for the development of robotic-assisted spine surgery.