During transfer tasks, the dual-arm nursing-care robot require a human-robot mechanics model to determine the balance region to support the patient safely and stably. Previous studies utilized human-robot two-dimensional static equilibrium models, ignoring the human body volume and muscle torques, which decreased model accuracy and confined the robot ability to adjust the patient's posture in three-dimensional spatial. Therefore, this study proposes a three-dimensional spatial mechanics modeling method based on individualized human musculoskeletal multibody dynamics. Firstly, based on the mechanical features of dual-arm support, this study constructed a foundational three-dimensional human-robot mechanics model including body posture, contact position and body force. With the computed tomography data from subjects, a three-dimensional femur-pelvis-sacrum model was reconstructed, and the individualized musculoskeletal dynamics was analyzed using the ergonomics software, which derived the human joint forces and completed the mechanic model. Then, this study established a dual-arm robot transfer platform to conduct subject transfer experiments, showing that the constructed mechanics model possessed higher accuracy than previous methods. In summary, this study provides a three-dimensional human-robot mechanics model adapting to individual transfers, which has potential application in various scenarios such as nursing-care and rehabilitating robots.
Humans ; Robotics ; Biomechanical Phenomena ; Posture ; Imaging, Three-Dimensional ; Nursing Care

Lung cancer is the leading cause of cancer-related deaths worldwide. Radiation pneumonitis is a major complication in lung cancer radiotherapy. Four-dimensional computed tomography (4DCT) imaging provides dynamic ventilation information, which is valuable for lung function assessment and radiation pneumonitis prevention. Many methods have been developed to calculate lung ventilation from 4DCT, but a systematic comparison is lacking. Prediction of radiation pneumonitis using 4DCT-based ventilation is still in an early stage, and no comprehensive review exists. This paper presented the first systematic comparison of functional lung ventilation algorithms based on 4DCT over the past 15 years, highlighting their clinical value and limitations. It then reviewed multimodal approaches combining 4DCT ventilation imaging, dose metrics, and clinical data for radiation pneumonitis prediction. Finally, it summarized current research and future directions of 4DCT in lung cancer radiotherapy, offering insights for clinical practice and further studies.
Humans ; Lung Neoplasms/diagnostic imaging* ; Four-Dimensional Computed Tomography/methods* ; Radiation Pneumonitis/etiology* ; Algorithms ; Lung/radiation effects* ; Pulmonary Ventilation

OBJECTIVE: To investigate the effectiveness of using 3 hollow compression screws combined with 1 screw off-axis fixation under the guidance of three-dimensional (3D) printed guide plate with mortise-tenon joint structure (mortise-tenon joint plate) for the treatment of Pauwels type Ⅲ femoral neck fractures. METHODS: A clinical data of 78 patients with Pauwels type Ⅲ femoral neck fractures, who were admitted between August 2022 and August 2023 and met the selection criteria, was retrospectively analyzed. The operations were assisted with mortise-tenon joint plates in 26 cases (mortise-tenon joint plate group) and traditional guide plates in 28 cases (traditional plate group), and without guide plates in 24 cases (control group). There was no significant difference in the baseline data of gender, age, body mass index, cause of injury, and fracture side between groups ( P>0.05). The operation time, intraoperative blood loss, frequency of intraoperative fluoroscopy, incision length, incidence of postoperative deep vein thrombosis of lower extremity, pain visual analogue scale (VAS) score at 1 week after operation, and Harris score of hip joint at 3 months after operation were recorded and compared. X-ray re-examination was taken to check the quality of fracture reduction, fracture healing, and the shortening length of the femoral neck at 3 months after operation, and the incidences of internal fixation failure and osteonecrosis of the femoral head during operation. RESULTS: Compared with the control group, the operation time, intraoperative blood loss, and frequency of intraoperative fluoroscopy reduced in the two plate groups, and the quality of fracture reduction was better, but the incision was longer, and the differences were significant ( P<0.05). The operation time and intraoperative blood loss were significantly higher in the traditional plate group than in the mortise-tenon joint plate group ( P<0.05), the incision was significantly longer ( P<0.05); and the difference in fracture reduction quality and the frequency of intraoperative fluoroscopy was not significant between two plate groups ( P>0.05). There was 1 case of deep vein thrombosis of lower extremity in the traditional plate group and 1 case in the control group, while there was no thrombosis in the mortise-tenon joint plate group. There was no significant difference in the incidence between groups ( P>0.05). All patients were followed up 12-15 months (mean, 13 months). There was no significant difference in VAS score at 1 week and Harris score at 3 months between groups ( P>0.05). Compared with the control group, the fracture healing time and the length of femoral neck shortening at 3 months after operation were significantly shorter in the two plate groups ( P<0.05). There was no significant difference between the two plate groups ( P>0.05). There was no significant difference in the incidences of non-union fractures, osteonecrosis of the femoral head, or internal fixation failure between groups ( P>0.05). CONCLUSION For Pauwels type Ⅲ femoral neck fractures, the use of 3D printed guide plate assisted reduction and fixation can shorten the fracture healing time, reduce the incidence of postoperative complications, and be more conducive to the early functional exercise of the affected limb. Compared with the traditional guide plate, the mortise-tenon joint plate can reduce the intraoperative bleeding and shorten the operation time.
Humans ; Femoral Neck Fractures/diagnostic imaging* ; Bone Plates ; Fracture Fixation, Internal/instrumentation* ; Male ; Female ; Retrospective Studies ; Middle Aged ; Bone Screws ; Adult ; Aged ; Treatment Outcome ; Printing, Three-Dimensional ; Operative Time

OBJECTIVE: To explore the anatomical parameters of the cervical uncinate process "inflection point" through cervical CT angiography (CTA) and MRI measurements, offering a reliable and safe anatomical landmark for anterior cervical decompression surgery. METHODS: A retrospective analysis was conducted on the cervical CTA and MRI imaging data of normal adults who met the selection criteria between January 2020 and January 2024. The CTA dataset included 326 cases, with 200 males and 126 females, aged 22-55 years (mean, 46.7 years). The MRI dataset included 300 cases, with 200 males and 100 females, aged 18-55 years (mean, 43.7 years). Based on the CTA data, three-dimensional models of C ₃-C ₇ were constructed, and the following measurements were obtained from the superior view: uncinate process "inflection point" to vertebral artery distance (UIVD), uncinate process tip to vertebral artery distance (UTVD), uncinate process "inflection point" to "inflection point" distance (UID), uncinate process long-axis to sagittal angle (ULSA), and uncinate process "inflection point" to transverse foramen-sagittal angle (UITSA). From the anterior view, the anterior uncinate process to sagittal angle (AUSA) was measured. From the posterior view, the posterior uncinate process to sagittal angle (PUSA) was measured. Based on the MRI data, uncinate process "inflection point" to dural sac distance (UIDD) and dural sac width (DSW) were measured. The trends in measurement parameters of C ₃-C ₇ were observed, and the differences in measurement parameters between genders and between the left and right sides of the same segment were compared, as well as the difference in UID and DSW within the same segment was compared. RESULTS: The measurement parameters from C ₃ to C ₇ in the CTA data showed a general increasing trend, with no significant difference between the left and right sides within the same segment ( P>0.05). The UIVD, UTVD, and UID were greater in males than in females, with significant differences observed in the UIVD and UTVD at C ₃ and C ₆ and UID at C ₃, C ₆, and C ₇ ( P<0.05). The MRI measured DSW showed a general increasing trend from C ₃ to C ₇, and the DSW at C ₆ was greater in females than in males, with a significant difference ( P<0.05). The UIDD showed a gradual decreasing trend, with the smallest value at C ₆. There was no significant difference between males and females or between the left and right sides within the same segment ( P>0.05). The UID was greater than the DSW at C ₃-C ₇, and the differences were significant ( P<0.05). CONCLUSION The uncinate process "inflection point" is a constant anatomical structure located at the anteromedial aspect of the uncinate process tip and laterally to the dural sac. It maintains a certain safe distance from the vertebral artery. As a decompression landmark in anterior cervical spine surgery, it not only ensures surgical safety but also guarantees complete decompression.
Humans ; Adult ; Male ; Female ; Middle Aged ; Retrospective Studies ; Cervical Vertebrae/surgery* ; Magnetic Resonance Imaging ; Decompression, Surgical/methods* ; Young Adult ; Adolescent ; Computed Tomography Angiography ; Imaging, Three-Dimensional ; Vertebral Artery/anatomy & histology* ; Anatomic Landmarks/diagnostic imaging*

OBJECTIVE: To investigate the effectiveness of digital three-dimensional (3D) assisted unilateral biportal endoscopy (UBE) in the treatment of highly isolated lumbar disc herniation (LDH) with translaminar approach. METHODS: The clinical data of 59 patients who met the selection criteria and underwent UBE treatment due to highly isolated LDH between January 2022 and December 2023 were retrospectively analyzed. Among them, 25 cases were treated with digital 3D assisted translaminar approach (observation group) and 34 cases were treated with interlaminar approach (control group). There was no significant difference in gender, age, disease duration, surgical segment, and preoperative visual analogue scale (VAS) score and Oswestry disability index (ODI) between the two groups ( P>0.05). The operation time, intraoperative blood loss, and lateral articular surface preservation rate were recorded and compared between the two groups. VAS score and ODI were used to evaluate the improvements of pain and function before operation and at 3 and 6 months after operation. The modified MacNab criteria was used to evaluate the effectiveness at last follow-up. RESULTS: One patient in the control group had dural tear, and the other patients had no nerve injury, infection, dural tear, or other related complications. There was no significant difference in operation time and intraoperative blood loss between the two groups ( P>0.05). Patients in both groups were followed up 6-13 months, with an average of 8.3 months. The lateral articular surface preservation rate in the observation group was significantly higher than that in the control group ( P<0.05). Three patients in the observation group and 2 patients in the control group had calf muscle venous thrombosis, which was cured after anticoagulant treatment with rivaroxaban and delayed exercise time. There was no recurrence or second operation during the follow-up period. The VAS score and ODI of the two groups at 3 and 6 months after operation significantly improved when compared with those before operation ( P<0.05). There was no significant difference between the two groups at each time point after operation ( P>0.05). At last follow-up, the effectiveness was evaluated according to the modified MacNab criteria, and there was no significant difference in the evaluation grade and excellent and good rate between the two groups ( P>0.05). CONCLUTION UBE via translaminar approach is safe and effective for the treatment of highly isolated LDH, which is beneficial to protect the facet joint, maintain spinal stability, and reduce soft tissue injury. With the assistance of digital 3D technique, preoperative planning can be performed accurately.
Humans ; Intervertebral Disc Displacement/diagnostic imaging* ; Lumbar Vertebrae/diagnostic imaging* ; Male ; Retrospective Studies ; Female ; Endoscopy/methods* ; Treatment Outcome ; Middle Aged ; Adult ; Imaging, Three-Dimensional ; Operative Time ; Pain Measurement

OBJECTIVE: To compare the biomechanical properties of personalized Y-shaped plates with horizontal plates, vertical plates, and traditional Y-shaped plates in the treatment of distal humeral intra-articular fractures through finite element analysis, and to evaluate their potential for clinical application. METHODS: The study selected a 38-year-old male volunteer and obtained a three-dimensional model of the humerus by scanning his upper limbs using a 64-slice spiral CT. Four types of fracture-internal fixation models were constructed using Mimics 19.0, Geomagic Wrap 2017, Creo 6.0, and other software: horizontal plates, vertical plates, traditional Y-shaped plate, and personalized Y-shaped plate. The models were then meshed using Hypermesh 14.0 software, and material properties and boundary conditions were defined in Abaqus 6.14 software. AnyBody 7.3 software was used to simulate elbow flexion and extension movements, calculate muscle strength, joint forces, and load torques, and compare the peak stress and maximum displacement of the four fixation methods at different motion angles (10°, 30°, 50°, 70°, 90°, 110°, 130°, 150°) during elbow flexion and extension. RESULTS: Under dynamic loading during elbow flexion and extension, the personalized Y-shaped plate exhibits significant biomechanical advantages. During elbow flexion, the peak internal fixation stress of the personalized Y-shaped plate was (28.8±0.9) MPa, which was significantly lower than that of the horizontal plates, vertical plates, and traditional Y-shaped plate ( P<0.05). During elbow extension, the peak internal fixation stress of the personalized Y-shaped plate was (18.1±1.6) MPa, which was lower than those of the other three models, with significant differences when compared with horizontal plates and vertical plates ( P<0.05). Regarding the peak humeral stress, the personalized Y-shaped plate model showed mean values of (10.9±0.8) and (13.1±1.4) MPa during elbow flexion and extension, respectively, which were significantly lower than those of the other three models ( P<0.05). Displacement analysis showed that the maximum displacement of the humerus with the personalized Y-shaped plate during elbow flexion was (2.03±0.08) mm, slightly higher than that of the horizontal plates, but significantly lower than that of the vertical plates, showing significant differences ( P<0.05). During elbow extension, the maximum displacement of the humerus with the personalized Y-shaped plate was (1.93±0.13) mm, which was lower than that of the other three models, with significant differences when compared with vertical plates and traditional Y-shaped plates ( P<0.05). Stress contour analysis showed that the stress of the personalized Y-shaped plate was primarily concentrated at the bifurcation of the Y-shaped structure. Displacement contour analysis showed that the personalized Y-shaped plate effectively controlled the displacement of the distal humerus during both flexion and extension, demonstrating excellent stability. CONCLUSION The personalized Y-shaped plate demonstrates excellent biomechanical performance in the treatment of distal humeral intra-articular fractures, with lower stress and displacement, providing more stable fixation effects.
Humans ; Male ; Adult ; Healthy Volunteers ; Finite Element Analysis ; Tomography, Spiral Computed ; Models, Anatomic ; Biomechanical Phenomena ; Humeral Fractures, Distal/surgery* ; Fracture Fixation, Internal/instrumentation* ; Bone Plates ; Computer Simulation ; Precision Medicine/methods* ; Elbow Joint/surgery* ; Elbow/surgery* ; Humerus/surgery* ; Torque ; Stress, Mechanical ; Intra-Articular Fractures/surgery* ; Prosthesis Design/methods* ; Imaging, Three-Dimensional ; Range of Motion, Articular

OBJECTIVE: To explore the differences in the implantation safety and stability of a S ₁ alar-iliac screw (S1AIS) or S2AIS for sacroiliac joint fixation, providing reference for selecting appropriate internal fixation in clinical practice. METHODS: Patients who underwent pelvic CT examination between January 2024 and December 2024 were selected. CT data from 80 patients with normal pelvic structure who met the selection criteria were included in a 1∶1 male to female ratio. CT digital reconstruction technology was used to measure the transverse and longitudinal diameters of the S1AIS and S2AIS insertable ranges, as well as the length, width, and sacral side length of the screw trajectory. The pelvic CT data from 30 patients were randomly selected based on a 1∶1 male to female ratio for three-dimensional (3D) printing of pelvic samples. The S1AIS/S2AIS with a diameter of 6.5 mm and 8.0 mm were implanted at the optimal entry/exit points on the left and right sides, respectively, to observe the perforation of the screw trajectory. The pelvic CT data from 1 patient was randomly selected for 3D printing of 10 pelvic samples to simulate Tile C2 fracture. They were divided into S1AIS group ( n=5) and S2AIS group ( n=5), with one S1AIS and one S2AIS fixation used for posterior sacroiliac joint separation, and the specimen stiffness and maximum load were measured by using an electric tension torsion dual axis universal mechanical tester. RESULTS: The anatomical parameter measurement showed that there was no significant difference in the length and width of the screw trajectory between S1AIS and S2AIS ( P>0.05), but the transverse and longitudinal diameters of the insertable ranges, as well as the sacral side length of the screw trajectory, were all greater than those of S2AIS, with significant differences ( P<0.05). After simulating the implantation of S1AIS and S2AIS with a diameter of 6.5 mm in pelvic specimens, no screw penetration was observed. Both S1AIS and S2AIS with a diameter of 8.0 mm showed screw penetration, with S2AIS having a higher incidence of posterior lateral sacral cortical penetration (46.7%) than S1AIS (3.3%) ( P<0.05). The biomechanical test showed that the stiffness and maximum load of S2AIS were significantly lower than those of S1AIS ( P<0.05). CONCLUSION As a method to fix the sacroiliac joint, the S1AIS has a larger insertable range, a longer sacral side length of the screw trajectory, a lower incidence of posterior lateral cortical rupture of the sacrum, and a greater fixation strength than S2AIS. Therefore, the implantation safety and fixation stability of the S1AIS are superior to S2AIS, and a diameter less than 8.0 mm screws should be selected as S2AIS for Chinese people.
Humans ; Bone Screws ; Sacroiliac Joint/diagnostic imaging* ; Male ; Female ; Sacrum/diagnostic imaging* ; Fracture Fixation, Internal/instrumentation* ; Ilium/diagnostic imaging* ; Tomography, X-Ray Computed ; Middle Aged ; Adult ; Printing, Three-Dimensional ; Aged

OBJECTIVE: To investigate the application of three-dimensional (3D) reconstruction technology in preoperative planning for anterolateral thigh flap transplantation. METHODS: A retrospective analysis was performed on the clinical data of 11 patients with skin and soft tissue defects treated with free anterolateral thigh flap transplantation between January 2022 and January 2024, who met the selection criteria. There were 8 males and 3 females, aged 34-70 years (mean, 50.8 years). Causes of injury included traffic accidents (4 cases), machine trauma (3 cases), heavy object crush injury (3 cases), and tumor (1 case). The time from injury to flap repair ranged from 7 to 35 days (mean, 23 days). Preoperatively, the patients' CT angiography images were imported into Mimics21.0 software. Through the software's segmentation, editing, and reconstruction functions, 3D visualization and measurement of the vascular pedicle, perforators, wound size, and morphology were performed to plan the flap harvest area, contour, vascular pedicle length, and anastomosis site, guiding the implementation of flap transplantation. RESULTS: The length of the vascular pedicle needed by the recipient site was (9.1±0.9) cm, and the maximum length of vascular pedicle in the donor area was (10.6±0.6) cm, with a significant difference ( t=4.230, P<0.001). The operation time ranged from 220 to 600 minutes (mean, 361.9 minutes). One patient had poor wound healing at the recipient site, which healed after dressing changes. All 11 flaps survived well without necrosis. All patients were followed up 6-19 months (mean, 11 months). Four flaps showed bulkiness and underwent secondary debulking; the remaining flaps had good contour and soft texture. The donor sites healed well, with no sensory disturbance around the incision or complications such as walking impairment. CONCLUSION Preoperative planning using CT angiography data and 3D reconstruction software can effectively determine the flap area, contour, required vascular pedicle length, anastomosis site, and whether vascular grafting is needed, thereby guiding the successful execution of anterolateral thigh flap transplantation.
Humans ; Middle Aged ; Male ; Female ; Adult ; Thigh/diagnostic imaging* ; Aged ; Plastic Surgery Procedures/methods* ; Retrospective Studies ; Imaging, Three-Dimensional/methods* ; Soft Tissue Injuries/surgery* ; Surgical Flaps ; Computed Tomography Angiography ; Free Tissue Flaps/blood supply* ; Preoperative Care

OBJECTIVE: To explore the application progress and clinical value of digital technologies in the surgical treatment of ankylosing spondylitis (AS). METHODS: By systematically reviewing domestic and international literature, the study summarized the specific application scenarios, operational procedures, and technical advantages of digital technologies [including preoperative three-dimensional (3D) planning, intraoperative real-time navigation, robot-assisted surgery, and 3D printing] in AS surgery, and analyzed their impact on surgical accuracy, complication rates, and clinical outcomes. RESULTS: Digital technologies significantly improve the precision and safety of AS surgery. Preoperative 3D planning enables personalized surgical protocols; intraoperative navigation systems dynamically adjusts surgical trajectories, reducing the risk of iatrogenic injury; robot-assisted surgery can minimize human errors and enhance implant positioning accuracy; 3D-printed anatomical models and guides optimize the correction of complex spinal deformities. Furthermore, the combined applications of these technologies shorten operative time, reduce intraoperative blood loss, decrease postoperative complications (e.g., infection, nerve injury), and accelerate functional recovery. CONCLUSION Through multidimensional integration and innovation, digital technologies provide a precise and minimally invasive solution for AS surgical treatment. Future research should focus on their synergy with biomaterials and intelligent algorithms to further refine surgical strategies and improve long-term prognosis.
Humans ; Spondylitis, Ankylosing/diagnostic imaging* ; Printing, Three-Dimensional ; Surgery, Computer-Assisted/methods* ; Robotic Surgical Procedures/methods* ; Imaging, Three-Dimensional ; Postoperative Complications/prevention & control* ; Digital Technology ; Models, Anatomic

OBJECTIVE: To explore the biomechanical characteristics and clinical application effects of three-dimensional (3D) printed osteotomy guide plate combined with Ilizarov technique in the treatment of rigid clubfoot. METHODS: A retrospective analysis was performed on the clinical data of 11 patients with rigid clubfoot who met the inclusion criteria and were admitted between January 2019 and December 2024. There were 6 males and 5 females, aged 21-60 years with an average of 43.2 years. Among them, 5 cases were untreated congenital rigid clubfoot, 4 cases were recurrent rigid clubfoot after previous treatment, and 2 cases were rigid clubfoot due to disease sequelae. All 11 patients first received slow distraction using Ilizarov technique combined with circular external fixator until the force lines of the foot and ankle joint were basically normal. Then, 1 male patient aged 24 years was selected, and CT scanning was used to obtain imaging data of the ankle joint and foot. A 3D finite element model was established and validated using the plantar stress distribution nephogram of the patient. After validation, the biomechanical changes of the tibiotalar joint under the same load were simulated after triple arthrodesis and fixation. The optimal correction angle of the hindfoot was determined to fabricate 3D-printed osteotomy guide plates, and all 11 patients underwent triple arthrodesis using these guide plates. The functional recovery was evaluated by comparing the American Orthopaedic Foot and Ankle Society (AOFAS) score, International Clubfoot Study Group (ICFSG) score, and 36-Item Short Form Survey (SF-36) score before and after operation. RESULTS: Finite element analysis showed that the maximum peak von Mises stress of the tibiotalar joint was at hindfoot varus 3° and the minimum at valgus 6°; the maximum peak von Mises stress of the 3 naviculocuneiform joints under various conditions appeared at lateral naviculocuneiform joint before operation, and the minimum appeared at lateral naviculocuneiform joint at neutral position 0°; the maximum peak von Mises stress of the 5 tarsometatarsal joints under various conditions appeared at the 2nd tarsometatarsal joint at hindfoot neutral position 0°, and the minimum appeared at the 1st tarsometatarsal joint at valgus 6°. Clinical application results showed that the characteristics of clubfoot deformity observed during operation were consistent with the preoperative 3D reconstruction model. All 11 patients were followed up 8-24 months with an average of 13.1 months. One patient had postoperative incision exudation, which healed after dressing change; the remaining patients had good incision healing. All patients achieved good healing of the osteotomy segments, with a healing time of 3-6 months and an average of 4.1 months. At last follow-up, the AOFAS score, SF-36 score, and ICFSG score significantly improved when compared with those before operation ( P<0.05). CONCLUSION The 3D-printed osteotomy guide plate combined with Ilizarov technique has favorable biomechanical advantages in the treatment of rigid clubfoot, with significant clinical application effects. It can effectively improve the foot function of patients and achieve precise and personalized treatment.
Humans ; Clubfoot/diagnostic imaging* ; Printing, Three-Dimensional ; Male ; Osteotomy/instrumentation* ; Female ; Ilizarov Technique/instrumentation* ; Adult ; Retrospective Studies ; Biomechanical Phenomena ; Middle Aged ; Bone Plates ; Young Adult ; Finite Element Analysis ; Treatment Outcome ; Ankle Joint/physiopathology* ; Tomography, X-Ray Computed ; External Fixators