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

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

Robotic navigation during spine surgery: an update of literature

INTRODUCTION

The application of robotic navigation during spine surgery has advanced rapidly over the past two decades, especially in the last 5 years. Robotic systems in spine surgery may offer potential advantages for both patients and surgeons. This article serves as an update to our previous review and explores the current status of spine surgery robots in clinical settings.

AREAS COVERED

We evaluated the literature published from 2020 to 2022 on the outcomes of robotics-assisted spine surgery, including accuracy and its influencing factors, radiation exposure, and follow-up results.

EXPERT OPINION

The application of robotics in spine surgery has driven spine surgery into a new era of precision treatment through a form of artificial intelligence assistance that compensates for the limitations of human abilities. Modularized robot configurations, intelligent alignment and planning incorporating multimodal images, efficient and simple human-machine interaction, accurate surgical status monitoring, and safe control strategies are the main technical features for the development of orthopedic surgical robots. The use of robotics-assisted decompression, osteotomies, and decision-making warrants further study. Future investigations should focus on patients' needs while continuing to explore in-depth medical-industrial collaborative development innovations that improve the overall utilization of artificial intelligence and sophistication in disease treatment.

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.

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

BACKGROUND

This study aimed to explore the imaging characteristics, diversity and changing trend in CT scans of pediatric patients infected with Delta-variant strain by studying imaging features of children infected with Delta and comparing the results to those of children with original COVID-19.

METHODS

A retrospective, comparative analysis of initial chest CT manifestations between 63 pediatric patients infected with Delta variant in 2021 and 23 pediatric patients with COVID-19 in 2020 was conducted. Corresponding imaging features were analyzed. In addition, the changing trend in imaging features of COVID-19 Delta-variant cases were explored by evaluating the initial and follow-up CT scans.

RESULTS

Among 63 children with Delta-variant COVID-19 in 2021, 34 (53.9%) showed positive chest CT presentation; and their CT score (1.10 ± 1.41) was significantly lower than that in 2020 (2.56 ± 3.5) (P = 0.0073). Lesion distribution: lung lesions of Delta cases appear mainly in the lower lungs on both sides. Most children had single lobe involvement (18 cases, 52.9%), 14 (41.2%) in the right lung alone, and 14 (41.2%) in both lungs. A majority of Delta cases displayed initially ground glass (23 cases, 67.6%) and nodular shadows (13 cases, 38.2%) in the first CT scan, with few extrapulmonary manifestations. The 34 children with abnormal chest CT for the first time have a total of 92 chest CT examinations. These children showed a statistically significant difference between the 0-3 day group and the 4-7 day group (P = 0.0392) and a significant difference between the 4-7 day group and the more than 8 days group (P = 0.0003).

CONCLUSIONS

The early manifestations of COVID-19 in children with abnormal imaging are mostly small subpleural nodular ground glass opacity. The changes on the Delta-variant COVID-19 chest CT were milder than the original strain. The lesions reached a peak on CT in 4-7 days and quickly improved and absorbed after a week. Dynamic CT re-examination can achieve a good prognosis.

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

BACKGROUND

The aim of this study was to analyze the clinical characteristics of 66 pediatric patients with B.1.617.2 (Delta) variant of coronavirus disease 2019 (COVID-19).

METHODS

Sixty-six pediatric patients with B.1.617.2 (Delta) variant of COVID-19 admitted to the hospital from July to August 2021 were classified into mild (n = 41) and moderate groups (n = 25). Clinical characteristics, laboratory data and dynamic trends in different time periods were analyzed retrospectively.

RESULTS

There were no statistically significant differences in age, gender ratios and clinical symptoms between the mild group and the moderate group. All the patients in the moderate group had clusters of onsets, and the incubation period was shorter than that of the mild group. Within 24 hours of admission, the levels of erythrocyte sedimentation rate, cardiac troponin I, D-dimer in the moderate group were higher than that in the mild group (P < 0.05). The titers of immunoglobulin (Ig) G and IgM antibodies gradually increased after disease onset. Thirty-five (53.03%) children were tested positive for antibodies in 4-12 days. IgG increased gradually, while IgM decreased obviously in about 15 days after disease onset. The cycle threshold values of open reading frame 1ab and nucleocapsid protein gene in the severe acute respiratory syndrome coronavirus 2 genomes increased gradually on the 3rd, 6th, 9th, and 12th days after disease onset, compared with those in day 0.

CONCLUSIONS

The symptoms of children with B.1.617.2 (Delta) variant of COVID-19 were mild. The description and analysis of the clinical characteristics and laboratory data can help medical staff to evaluate the condition of children with COVID-19 and to accumulate more clinical experience.

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.

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

Objective

To evaluate the effects of early ambulation on elderly patients’ postoperative physical functional outcomes, complications, 90‐day readmission rate, and the length of postoperative hospital stay.

Methods

This is a prospective cohort study conducted between June 2019 and December 2019. The study enrolled 86 elderly patients (39 males) with newly diagnosed lumbar degenerative disease undergoing single‐segment decompression and fusion surgerywere enrolled. Of all 86 patients, 39 voluntarily joined the early ambulation group, and 47 joined the regular ambulation group. The early ambulation group included patients ambulated within 4 h postoperatively, whereas the regular ambulation group included patients who were ambulatory at a minimum of 24 h after surgery. Participants’ baseline characteristics, surgical information, ambulation ability, degree of pain, functional scores, postoperative complications, 90‐day readmission rate, and length of postoperative hospital stay were recorded.

Results

Participants’ baseline demographic characteristics were balanced between the early ambulation group and the regular ambulation group. The operative time and blood loss were similar between groups. The time before the first‐time ambulation was 4 ± 0.5 h in the early ambulation group and 28 ± 4.5 h in the regular ambulation group. Ambulating distance was significantly longer in the early ambulation group compared with the regular ambulation group on the 1st (63 ± 45 vs 23 ± 60 m), the 2nd (224 ± 100 vs 101 ± 130 m), and the 3rd (280 ± 102.5 vs 190 ± 170 m) ambulation days based on generalized estimating equation analyses. Generalized estimating equation analyses also demonstrated that the ambulating time was longer in the early ambulation group compared with the regular ambulation group on the 1st (10 ± 5 vs 10 ± 5 min), the 2nd (19 ± 7 vs 15 ± 5 min), and the 3rd (22 ± 16.5 vs 27 ± 12 min) ambulation days. Patients in the regular ambulation group experienced a higher degree of pain than the early ambulation group patients, with an odds ratio of 1.627 (P = 0.002). Short‐term functional independence was superior in the early ambulation group, with a lower Roland–Morris disability questionnaire score (P = 0.008) and Oswestry disability index (P < 0.001). The incidences of postoperative urinary retention (early ambulation group: 7.7%, regular ambulation group: 25.5%, P = 0.030) and ileus (early ambulation group: 0%, regular ambulation group: 12.8%, P = 0.030) were significantly higher in the regular ambulation group. The prevalence of at least one complication rate was significantly lower in the early ambulation group than in the regular ambulation group (early ambulation group, 23.1%; regular ambulation group, 46.8%, P = 0.022). The duration of indwelling of the drainage catheter was shorter in the early ambulation group (early ambulation group, 68 ± 24 h; regular ambulation group, 78 ± 20 h, P = 0.001), and the length of the postoperative hospital stay was also shorter in the early ambulation group (early ambulation group, 4 ± 0 days; regular ambulation group: 5 ± 2 days, P < 0.001). However, there was no statistical difference in the 90‐day readmission rate between groups.

Conclusion

Early ambulation improved patients’ postoperative functional status, decreased the incidence of complications, and shortened postoperative hospital stay in elderly patients undergoing lumbar decompression and fusion surgery.

[Accuracy of 6D computed-derived implant guides made in China for dental implant surgery in edentulous patients]

PURPOSE

To evaluate the accuracy of 6D computed-derived implant guides made in China, in order to provide methods and basis for reducing deviation.

METHODS

3D rapid prototyping technique was used to fabricate implant guides for auxiliary surgical implantation in edentulous patients, and the position deviation between the preoperative design and the actual implant was measured. Sixteen edentulous patients with 172 implantation sites were measured. In 10 patients, six implants were implanted in the maxilla, 4 implants in the mandible, and 6 implants were implanted both in the maxilla and mandible of 6 patients. A total of 28 implants were tilted implant in 14 patients. Preoperative cone-beam CT(CBCT) data were imported into the 6D Dental Planning Software to design and make the implant guides. Digital guides were used to assist implant placement. Preoperative design and postoperative CBCT were imported into the software for 3D reconstruction and registration, and then exported to Geomagic Studio software for analysis to obtain the deviation between the preoperative design and the implantation, so as to analyze the accuracy of the guides. The differences were analyzed by SPSS 25.0 software package with paired t-test and single factor analysis of variance.

RESULTS

The distance deviation of implant neck center point was (0.83±0.27) mm and the horizontal deviation was (0.60±0.21) mm. The distance deviation of implant bottom center point was (1.11±0.35) mm, and the vertical deviation was (0.45±0.19) mm. The angle deviation was (3.16±1.73)°.

CONCLUSIONS

The 6D computed-derived implant guides made in China can improve the accuracy and efficiency of implant surgery for edentulous patients and obtain a better long-term clinical effect to meet clinical requirements well. Since the deviation is similar to other implant guide plate systems that reported aborad, it must be taken into account in the process of clinical design, in order to avoid risks and unnecessary complications. This method is worthy of wide clinical application.

Guideline for Posterior Atlantoaxial Internal Fixation Assisted by Orthopaedic Surgical Robot

Atlantoaxial transarticular facet screw fixation (Magerl technique) and C₁ lateral mass screws combined with C₂ pedicle screws fixation (Harms technique) are the most commonly used techniques for posterior internal fixation in the upper cervical spine. Upper cervical spinal surgery is a technically demanding and challenging procedure because of complicated anatomical structures and frequent occurrence of anomalies. Accurate insertion of screws allows for stable and secure internal fixation, which is necessary for both techniques. Traditional methods under fluoroscopic assistance in this region cannot meet the requirements of high levels of accuracy and security during the procedure. Robot-assisted spinal surgery can provide accurate and reliable guidance during the screw insertion, which is evidenced in the literature. As a recently developed technique, robot-assisted surgery is supposed to be performed by skilled surgeons who have received standard training for robotic surgery. The standardized upper cervical spinal surgery assisted by the robot system needs to be introduced to these surgeons. Based on the consensus of consultant specialists, the literature review, and our local experience, this guideline included the introduction of the robotic system, the workflow of robot-assisted procedures, and the precautions to take during procedures. This guideline aims to provide a standardization of the robotic surgery for posterior atlantoaxial internal fixation.

Guideline for Thoracolumbar Pedicle Screw Placement Assisted by Orthopaedic Surgical Robot

The pedicle screw placement procedure is the most commonly used technique for spinal fixation and can provide reliable three‐column stabilization. Accurate screw placement is necessary in clinical practice. To avoid screw malposition, which may decrease the stiffness of the screw‐rod construct or increase the likelihood of neural and vascular injuries, the surgeons must fully understand the regional anatomy. Deformities, such as scoliosis, kyphosis or congenital anomalies, may complicate the application of the pedicle screw placement technique and increase the chance of screw encroachments. Incidences of pedicle screw malposition vary in different districts and hospitals and with surgeons and techniques. Today, the minimally invasive spinal surgery is well developed. However, the narrow corridors and limited views for surgeons increase the difficulty of pedicle screw placement and the possibility of screw encroachment. Evidenced by previous studies, robotic surgery can provide accurate screw placement, especially in settings of spinal deformities, anatomical anomalies, and minimally invasive procedures. Based on the consensus of consultant specialists, the literature review and our local experiences, this guideline introduces the robotic system and describes the workflow of robot‐assisted procedures and the precautions to take during procedures. This guideline aims to outline a standardized method for robotic surgery for thoracolumbar pedicle screw placement.

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.

An Analysis of Paravertebral Ossification in Cervical Artificial Disc Replacement: A Novel Classification Based on Computed Tomography

OBJECTIVE

Cervical artificial disc replacement (CADR) is a new technology in cervical spine surgery. However, CADR may result in paravertebral ossification (PO) after surgery and affect the mobility of the related spinal segments. The present widely used assessment method based on X-ray tomography cannot provide the position information of PO, and also PO detection rates by X-ray are low. The incidence of PO varies dramatically between studies. This study built a novel classification system based on cervical computer tomography (CT) scan to re-evaluate the incidence of PO and its influence on CADR, and also analyzed the predisposing factors of PO.

METHODS

In this retrospective study, 71 patients (from January 2004 to December 2009) who received cervical artificial disc replacement in our hospital were enrolled, and 82 cervical segments were replaced by Bryan discs. The range of motion (ROM) of the related cervical segments and scores of neurological symptoms (neck disability index [NDI] and Japanese Orthopaedic Association [JOA] scores) for both pre-surgery and last follow-up were acquired, respectively. After the establishment of a novel grading system for PO based on CT scan, we analyzed the CT images acquired before surgery and at the last time follow-up. Occurrence and distribution of PO at both time points were calculated. ROM between pre-surgery and post-surgery was compared by paired t-test stratified by PO stages. One-way ANOVA was used to compare NDI and JOA scores between high-grade and low-grade PO groups after surgery. The χ² -test was used to evaluate the risk (odds ratio) of predisposing factors in developing high-grade PO after surgery.

RESULTS

The CT-based classification system has good inter-observer and intra-observer reliability. The detection rate of PO by CT scan is higher than for traditional X-ray examination. The incidence of low-grade PO in all 82 segments at last follow-up is 32.9%. The occurrences of high-grade PO at preoperational and last follow-up time are 15.9% and 67.1%, respectively. The high-grade PO is mainly distributed around the uncovertebral joint. The pre-surgery and post-surgery ROM are similar in patients with low-grade PO at last follow-up time (9.80° ± 3.65° vs 10.03° ± 3.73°, P = 0.801); however, in patients with high-grade PO the post-surgery ROM decreases significantly compared to the pre-surgery ROM (9.73° ± 4.03° vs 6.63° ± 4.21°, P < 0.001). There is no statistical difference for JOA and NDI scores after surgery between high-grade and low-grade PO patients at final follow-up (P = 0.264, P = 0.703). The χ² -test indicates that patients with preoperational existence of PO have a high risk of high-grade PO after surgery (OR = 4, P = 0.012).

CONCLUSIONS

The novel CT image-based PO classification system has good intra-observer reliability. The incidence of PO after Bryan cervical disk replacement is relative high, and the high-grade PO is mainly distributed at the uncovertebral joint. The high-grade PO will affect the ROM after surgery; however, it does not affect the neurologic symptoms.

[Morphological alterations in gray matter related to primary dysmenorrhea]

OBJECTIVE

To investigate the structural changes of gray matter in women with primary dysmenorrhea (PDM) and discuss the potential relationships between the changes and etiology of the disease.

METHODS

We used an optimized voxel-based morphometry (VBM) approach to compare total and regional volumetric changes of gray matter in 20 primary dysmenorrhea patients with 20 healthy age and menstrual cycle matched controls.All subjects were patients from the outpatient department of Tongji Hospital in 2015.

RESULTS

Abnormal volumetric decreases of gray matter were found in the left and right parahippocampus, the left and right middle temporal gyrus, the left and right superior parietal lobule, the left postcentral cortex, the left and right inferior parietal lobule, which involved in pain transmission, pain modulation and somatic sensation.

CONCLUSION

Abnormal gray matter volume changes are present in some encephalic regions of PDM patients.The functions of these regions are associated with pain modulation and somatic sensation, which suggests the changes are related with PDM.