Design and evaluation of an intelligent reduction robot system for the minimally invasive reduction in pelvic fractures

Intelligent robot-assisted fracture reduction system for the treatment of unstable pelvic fractures

BACKGROUND

Precise and minimally invasive closed reduction is the premise of minimally invasive internal fixation. This paper aims to explore the safety and efficacy of a robot-assisted fracture reduction system (RAFR) in the treatment of pelvic fractures and to analyze its clinical advantages and existing problems.

METHODS

The RAFR system intelligently designed the optimal reduction path and target position based on a preoperative three-dimensional(3D) CT scan of the patient. The reduction robotic arm automatically reduced the affected hemipelvis according to the pre-planned reduction path.

RESULTS

The average residual displacement was the 6.65 ± 3.59 mm. According to Matta's criteria, there were 7 excellent, 10 good, and 3 fair, and the excellent and good rate was 85%. No postoperative complications occurred.

CONCLUSION

In our study, the RAFR system could complete accurate and minimally invasive closed reduction for most patients with unstable pelvic fractures, which could achieve good fracture reduction quality and short-term efficacy.

Experimental research based on robot-assisted surgery: Lower limb fracture reduction surgery planning navigation system

Background and Aims

Lower extremity fracture reduction surgery is a key step in the treatment of lower extremity fractures. How to ensure high precision of fracture reduction while reducing secondary trauma during reduction is a difficult problem in current surgery.

Methods

First, segmentation and three-dimensional reconstruction are performed based on fracture computed tomography images. A cross-sectional point cloud extraction algorithm based on the normal filtering of the long axis of the bone is designed to obtain the cross-sectional point clouds of the distal bone and the proximal bone, and the optimal reset target pose of the broken bone is obtained by using the iterative closest point algorithm. Then, the optimal reset sequence of reset parameters was determined, combined with the broken bone collision detection algorithm, a surgical planning algorithm for lower limb fracture reset was proposed, which can effectively reduce the reset force while ensuring the accuracy of the reset process without collision.

Results

The average error of the reduction of the model bone was within 1.0 mm. The reduction operation using the planning and navigation system of lower extremity fracture reduction surgery can effectively reduce the reduction force. At the same time, it can better ensure the smooth change of the reduction force.

Conclusion

Planning and navigation system of lower extremity fracture reduction surgery is feasible and effective.

A Countertraction Closed Reduction Technique in Minimally Invasive Fixation of Recent Type C Pelvic Ring Injuries

OBJECTIVE

Closed reduction of pelvic injuries is a prerequisite and critical step in minimally invasive treatment. Achieving non-invasive closed reduction of pelvic injuries is a challenging clinical problem. This study demonstrated a non-invasive traction technique for closed reduction called countertraction closed reduction technique (CCRT) and evaluated its effectiveness for type C pelvic ring injuries.

METHOD

The data of patients with unstable pelvic fractures treated with CCRT and minimally invasive fixation were retrospectively reviewed from January 2017 to February 2022. Sacroiliac screws were placed to fix the posterior pelvic ring, and internal or external fixation was used to fix the anterior pelvic ring. Operation time, intraoperative blood loss, duration of hospital stay, fracture union and postoperative complications were recorded. Fracture reduction quality was evaluated using the Matta scoring criteria. Functional recovery and general quality of life were evaluated using the Majeed functional scoring criteria.

RESULTS

Thirteen patients (nine males and four females), with an average age of 49.6 years were treated with CCRT and followed up for a mean of 18.5 months. The average operation time was 137.2 minutes (range 92-195 minutes), the average intraoperative blood loss was 31.2 mL (range 10-120 mL) and the average duration of hospital stay was 14.3 days (range 4-32 days). All patients achieved bony union with an average union time of 11.9 weeks (range 10-16 weeks). According to the Matta radiographic criteria, the quality of fracture reduction was excellent in eight patients, good in four, and fair in one. The average Majeed functional score was 89.7 (range 78-100). The functional evaluation revealed that the outcomes were excellent in nine patients, and good in four patients. Complications included incision fat liquefaction in one patient, and heterotopic ossification in another patient. There were no surgical complications as a result of CCRT.

CONCLUSION

CCRT is a non-invasive closed reduction method for minimally invasive fixation of fresh Tile C1 and C2 pelvic fractures. The advantages of CCRT combined with minimally invasive treatment include a small surgical incision, reduced intraoperative bleeding, satisfactory fracture reduction, bone healing and functional recovery.

Comparison of freehand technique and a novel laser-guiding navigation system in femoral neck-cannulated screw fixation: a randomized controlled trial

Cannulated screw fixation is essential in treating femoral neck fractures, and the widely used freehand technique has several limitations. Therefore, we designed a new laser-positioning and navigation system and compared its efficacy with that of the traditional freehand technique in the cannulated screw fixation of femoral neck fractures. This randomized controlled single-blind trial recruited patients with femoral neck fracture, who were treated using either the newly designed laser-navigation device or the freehand technique. In in-vitro experiments, using the femoral neck model, the laser group was better than the freehand group in terms of operation time (P = 0.0153) and radiation exposure time (P < 0.001). In in-vivo experiments, involving 30 patients (15 in each group), the laser group was better than the freehand group in terms of operation time (P < 0.001), radiation exposure time (P < 0.001), blood loss (P < 0.001) and first success rate (P = 0.03). There was no difference in visual analog scale score, Harris score, and fracture-healing time between the two groups. In conclusion, the novel laser-guiding navigation system resulted in shorter operation time, less radiation exposure, and higher first success rate compared with the freehand technique. Further qualified investigations with a larger number of patients and longer follow-up are required in the future.

Fast and precise collision detection for detailed and complex physiological structures

BACKGROUND AND OBJECTIVES

Virtual reality has been proved indispensable in computer-assisted surgery, especially for surgical planning, and simulation systems. Collision detection is an essential part of surgery simulators and its accuracy and computational efficiency play a decisive role in the fidelity of simulations. Nevertheless, current collision detection methods in surgical simulation and planning struggle to meet precise requirements, especially for detailed and complex physiological structures. To address this, the primary objective of this study was to develop a new algorithm that enables fast and precise collision detection to facilitate the improvement of the realism of virtual reality surgical procedures.

METHODS

The method consists of two main parts, bounding spheres formation and two-level collision detection. A specified surface subdivision method is devised to reduce the radius of basic bounding spheres formed by circumcenters of underlying triangles. The spheres are then clustered and adjusted to obtain a compact personalized hierarchy whose position is updated in real time during surgical simulation, followed by two-level collision detection. Triangular facets with collision potential through interaction between hierarchies and then accurate results are obtained by means of precise detection phase. The effectiveness of the algorithm was evaluated in various models and surgical scenarios and was compared with prior relevant implementations.

RESULTS

Results on multiple models demonstrated that the method can generate a personalized hierarchy with fewer and smaller bounding spheres for tight wrapping. Simulation experiments proved that the proposed approach is significantly superior to comparable methods under the premise of error-free detection, even for severe model-model collision.

CONCLUSIONS

The algorithm proposed through this study enables higher numerical efficiency and detection accuracy, which is capable of significantly enlarging the fidelity/realism of haptic simulators and surgical planning methods.

Intelligent robot-assisted minimally invasive reduction system for reduction of unstable pelvic fractures

OBJECTIVE

Currently, minimally invasive internal fixation is recommended for the surgical treatment of unstable pelvic fractures. The premise and difficulty of minimally invasive internal fixation are minimally invasive reduction of fractures. This review aimed to investigate the indications, surgical strategy and techniques, safety, and efficacy of intelligent robot-assisted fracture reduction (RAFR) system of pelvic ring injuries.

METHODS

This retrospective study reviewed a case series from March 2021 to November 2021. A total of 22 patients with unstable pelvic fracture injuries underwent minimally invasive internal fixations. All pelvic ring fractures were reduced with our intelligent RAFR system. The robot system intelligently designs the optimal position and reduction path based on the patient's preoperative 3D CT. During the operation, the three-dimensional visualization of the fracture is realized through image registration, and the Robot completes the automatic reduction of the fracture. The global 3D point cloud error between the preoperative planning results and the actual postoperative reduction results was calculated. The postoperative reduction results of residual displacement were graded by the Matta Criteria.

RESULTS

Minimally invasive closed reduction procedures were completed in all 22 cases with our RAFR system. The average global 3D point cloud reduction error between the preoperative planning results and the actual postoperative reduction results was 3.41mm±1.83mm. The mean residual displacement was 4.61mm±3.29mm. Given the Matta criteria, 16 cases were excellent, five were good, and one was fair, with an excellent and good rate of 95.5%.

CONCLUSION

Our new pelvic fracture reduction robot system can complete intelligent and minimally invasive fracture reduction for most patients with unstable pelvic fractures. The system has intelligent reduction position and path planning and realizes stable pelvis control through a unique holding arm and a robotic arm. The operation process will not cause additional damage to the patient, which fully meets the clinical requirements. Our study demonstrated the safety and effectiveness of our robotic reduction system and its applicability and usability in clinical practice, thus paving the way towards Robot minimally invasive pelvic fracture surgeries.

TiRobot‑assisted versus conventional fluoroscopy-assisted percutaneous sacroiliac screw fixation for pelvic ring injuries: a meta‑analysis

BACKGROUND

The TiRobot is the only robot that has been reported in the literature for posterior pelvic injuries. We aim to compare TiRobot-assisted pelvic screw fixation with the conventional fluoroscopy-assisted percutaneous sacroiliac screw fixation.

METHODS

We conducted a meta-analysis to identify studies involving TiRobot‑assisted versus conventional percutaneous sacroiliac screw fixation for pelvic ring injuries in electronic databases, including Web of Science, Embase, PubMed, Cochrane Controlled Trials Register, Cochrane Library, Highwire, CBM, CNKI, VIP, and WanFang database, up to April 2022. The following keywords were used: "TiRobot," "robot," "robotic," "pelvic fracture," "screw fixation," "percutaneous," and "pelvic ring injury." Pooled effects of this meta-analysis were calculated using STATA SE version 15.0.

RESULTS

Compared with conventional fluoroscopy-assisted percutaneous sacroiliac screw fixation, TiRobot will result in less radiation exposure time of screw implantation (P = 0.000), less frequency of intraoperative fluoroscopy (P = 0.000), fewer guide wire attempts (P = 0.000), less intraoperative blood loss (P = 0.005), better screw accuracy (P = 0.011), better Majeed score (P = 0.031), and higher overall excellent and good rates of Majeed score (P = 0.018). However, there were no significant differences in terms of operative time (P = 0.055), fracture healing time (P = 0.365), and overall excellent and good rate of reduction accuracy (P = 0.426) between the two groups.

CONCLUSION

TiRobot-assisted fixation has less intraoperative fluoroscopy and intraoperative blood loss, superior screw accuracy, and Majeed score compared with conventional percutaneous sacroiliac screw fixation. TiRobot has no significant effect on operative time, fracture healing time, and reduction accuracy. Given the relevant possible biases in our meta-analysis, we required more adequately powered and better-designed RCT studies with long-term follow-up to reach a firmer conclusion.