A collaborative robotic platform for sensor-aware fibula osteotomies in mandibular reconstruction surgery.

Precision and safety are crucial in performing fibula osteotomy during mandibular reconstruction with free fibula flap (FFF). However, current clinical methods, such as template-guided osteotomy, have the potential to cause damage to fibular vessels. To address the challenge, this paper introduces the development of the surgical robot for fibula osteotomies in mandibular reconstruction surgery and propose an algorithm for sensor-aware hybrid force-motion control for safe osteotomy, which includes three parts: osteotomy motion modeling from surgeons' demonstrations, Dynamic-system-based admittance control and osteotomy sawed-through detection. As a result, the average linear variation of the osteotomized segments was 1.08±0.41mm, and the average angular variation was 1.32±0.65∘. The threshold of osteotomy sawed-through detection is 0.5 at which the average offset is 0.5mm. In conclusion, with the assistance of surgical robot for mandibular reconstruction, surgeons can perform fibula osteotomy precisely and safely.

A novel dynamic electromagnetic tracking navigation system for distal locking of intramedullary nails.

BACKGROUND: The accurate distal locking of intramedullary (IM) nails is a clinical challenge for surgeons. Although many navigation systems have been developed, a real-time guide method with free radiation exposure, better user convenience, and high cost performance has not been proposed. METHODS: This paper aims to develop an electromagnetic navigation system named TianXuan-MDTS that provides surgeons with a proven surgical solution. And the registration method with external landmarks for IM nails and calibration algorithm for guiders were proposed. A puncture experiment, model experiments measured by 3D Slicer and cadaver experiments (2 cadaveric leg specimens and 6 drilling operations) are conducted to evaluate its performance and stability. RESULTS: The registration deviations (TRE) is 1.05± 0.13 mm. In the puncture experiment, a success rate of 96% can be achieved in 45.94 s. TianXuan-MDTS were evaluated on 3 tibia model. The results demonstrated that all 9 screw holes were successfully prepared at a rate of 100% in 91.67 s. And the entry point, end point, and angular deviations were 1.60±0.20 mm, 1.47±0.18 mm, and 3.10±0.84°, respectively. Postoperative fluoroscopy in cadaver experiments showed that all drills were in the distal locking holes, with a success rate of 100% and the average time 143.17± 18.27 s. CONCLUSIONS: The experimental results indicate that our system with novel registration and calibration methods could serve as a feasible and promising tool to assist surgeons during distal locking.

The development of computer-aided patient-specific template design software for 3D printing in cranio-maxillofacial surgery.

BACKGROUND: The patient-specific templates for osteotomy often have complex surface features. Using current commercial software to design such templates is quite complicated, tedious and unrepeatable. AIMS: In this study, a novel surgical planning system for oral and maxillofacial surgery named EasyTemplate is developed, aiming to help doctors shorten the modelling time and assure the reliability in template design. MATERIALS & METHODS: In the simplified design process of an osteotomy guide, the main template can be formed efficiently using a surface offsetting algorithm, which is based on isosurface extraction and oriented bounding box. Thereafter, the cutting grooves can be generated automatically. RESULTS: A complicated surgical guide could be built accurately in about 10 min. Clinical orthognathic cases were conducted successfully using osteotomy and repositioning templates designed by EasyTemplate. DISCUSSION: Compared with commercially available softwares, higher efficiency and simpler design process were achieved, moreover, the time cost is one-third or even less. CONCLUSION: EasyTemplate can be a useful alternative to traditional softwares. This software allows the auto-generation algorithm which helps avoid a tedious modeling process while providing basic shapes for designers.

An electromagnetic tracking implantation navigation system in dentistry with virtual calibration.

BACKGROUND: Dental implant placement navigation systems based on optical tracking have been widely used in clinics. However, electromagnetic (EM) navigation method that does not suffer from problems of hidden line-of-light has not yet been described. METHODS: This work proposes an EM-guided navigation method named TianShu-ESNS with virtual calibration. Model (12 implants) and animal experiments (pig head: six implants) were conducted to evaluate its performance and stability. RESULT: The mean virtual calibration error was 0.83 ± 0.20 mm. The mean deviations at the entry point, end point and angle in the phantom experiment of TianShu-ESNS were 1.23 ± 0.17 mm, 1.59 ± 0.20 mm and 1.83 ± 0.27°, respectively. In the animal experiment, the same deviations were 1.25 ± 0.07 mm, 1.57 ± 0.35 mm and 1.90 ± 0.60°, respectively. CONCLUSIONS: The experimental results show that TianShu-ESNS with the virtual calibration method could serve as a promising tool to eliminate the line-of-light hidden problem and simplify operation procedure in dental implant placement.

Automatic robot-world calibration in an optical-navigated surgical robot system and its application for oral implant placement.

PURPOSE: Robot-world calibration, used to precisely determine the spatial relation between optical tracker and robot, is regarded as an essential step for optical-navigated surgical robot system to improve the surgical accuracy. However, these methods are complicated with numerous computation. Therefore, a more efficient method of a robot-world calibration is necessary. METHODS: A fully automatic robot-world calibration was proposed and applied in a surgical robot system for oral implant placement. Making full usage of the movement characteristics of a tandem robot, the least square fitting algorithm was implemented to calculate the relationship between the tool center point of the robot and the robot reference frame, with the robot-world calibration matrix obtained as result. RESULTS: The experiment was designed to verify the accuracy of the robot-world calibration. The average distance deviation was 1.11 mm, and the average angle deviation was 0.99°. From the animal experiment on the pig maxilla, the entry, apical and angle deviation of the surgical robot system were 1.44 ± 1.01 mm, 1.68 ± 0.76 mm, 1.01 ± 1.06°, respectively. CONCLUSION: The surgical robot system for oral implant placement with our robot-world calibration maintains a high precision. Besides, the operation range of the surgical tool is no longer limited by the visual range of the optical tracking device. Hence, it is unnecessary to adjust the optical tracking device for the planned implant trajectories to different positions and directions.

A review on computer-aided design and manufacturing of patient-specific maxillofacial implants.

Introduction: Various prefabricated maxillofacial implants are used in the clinical routine for the surgical treatment of patients. In addition to these prefabricated implants, customized CAD/CAM implants become increasingly important for a more precise replacement of damaged anatomical structures. This paper reviews the design and manufacturing of patient-specific implants for the maxillofacial area.Areas covered: The contribution of this publication is to give a state-of-the-art overview in the usage of customized facial implants. Moreover, it provides future perspectives, including 3D printing technologies, for the manufacturing of patient-individual facial implants that are based on patient's data acquisitions, like Computed Tomography (CT) or Magnetic Resonance Imaging (MRI).Expert opinion: The main target of this review is to present various designing software and 3D manufacturing technologies that have been applied to fabricate facial implants. In doing so, different CAD designing software's are discussed, which are based on various methods and have been implemented and evaluated by researchers. Finally, recent 3D printing technologies that have been applied to manufacture patient-individual implants will be introduced and discussed.

An approach to automated measuring morphological parameters of proximal femora on three-dimensional models.

PURPOSE: Analyses of the morphology of proximal femora are essential for preoperative planning and designing customized femoral stems in total hip arthroplasty as well as intramedullary nailing fixation. Various studies reported measurements and analyses on the general geometry of proximal femora three-dimensionally. However, the modeling and measurements are time-consuming and unfriendly to surgeons. Thus, automated measurement and modeling of the femoral medullary canal are critical to promote the clinical application. METHODS: An approach to automated measuring morphological parameters of proximal femur was proposed, and a software allowing importing femur models and manually locating the related anatomic landmarks was developed in the current study. 3D modeling of the femoral medullary canal was created by the semispherical iterative searching algorithm, and 16 key anatomic parameters of the proximal femur were automatically calculated by the least-squares fitting algorithm. RESULTS: By experimenting on 196 femur STL models, the average execution time of single measurement was 0.88 (SD = 0.13) s, and the intra-class correlation coefficient of 10 anatomic parameters was between 0.880 and 0.996, showing high intra-rater and inter-rater reliability. CONCLUSIONS: The parameters of proximal femur can be easily measured, and the 3D modeling of the femoral medullary canal can be rapidly achieved. The approach will be easily applicable to clinical practice and has the potential to be applied in the design of customized femoral stems.

A review of haptic simulator for oral and maxillofacial surgery based on virtual reality.

INTRODUCTION: Traditional medical training in oral and maxillofacial surgery (OMFS) may be limited by its low efficiency and high price due to the shortage of cadaver resources. With the combination of visual rendering and feedback force, surgery simulators become increasingly popular in hospitals and medical schools as an alternative to the traditional training. AREAS COVERED: The major goal of this review is to provide a comprehensive reference source of current and future developments of haptic OMFS simulators based on virtual reality (VR) for relevant researchers. EXPERT COMMENTARY: Visual rendering, haptic rendering, tissue deformation, and evaluation are key components of haptic surgery simulator based on VR. Compared with traditional medical training, virtual and tactical fusion of virtual environment in surgery simulator enables considerably vivid sensation, and the operators have more opportunities to practice surgical skills and receive objective evaluation as reference.