Clinical efficacy and performance evaluation of a bendable remote robot system for a bone tumour surgery: A pilot animal study.

BACKGROUND: Traditional open surgery for bone tumours sometimes has as a consequence an excessive removal of healthy bone tissue because of the limitations of rigid surgical instruments, increasing infection risk and recovery time. METHODS: We propose a remote robot with a 4.5-mm diameter bendable end-effector, offering four degrees of freedom for accessing the inside of the bone and performing tumour debridement. The preclinical studies evaluated the effectiveness, clinical scenario, and usability across 12 total surgeries-six phantom surgeries and six bovine bone surgeries. Evaluation criteria included skin incision size, bone window size, surgical time, removal rate, and conversion to open surgery. RESULTS: Preclinical studies demonstrated that the robotic approach requires significantly smaller incision size and procedure times than traditional open curettage. CONCLUSION: This study validated the performance of the proposed system by assessing its preclinical effectiveness and optimising surgical methods using human phantom and bovine bone tumour models.

Clinical evaluation of a fluoroscopic image-based laser guidance system in bone tumor surgery: A technical note.

This study presents a laser guidance system developed to enhance surgical accuracy and reduce radiation exposure in orthopedic surgeries. The system can project the actual position corresponding to the appointed position selected by the surgeon on a fluoroscopic image using a line laser and has laser projection ability to mark the corresponding point using a line laser. The surgeon does not have to perform anatomical marker placement for calibration. Three patients with bone tumors underwent surgeries using the laser guidance system, and the projection accuracy was evaluated by measuring the distance error between the appointed and laser-marking positions. The installation time, including calibration, was also assessed for clinical usability. The average projection accuracy in bone tumor surgery was 2.86 mm, and the average installation time was 7 min. These results demonstrate that the laser guidance system, with a projection error of <3 mm, could be useful in bone tumor surgeries.

Robot-patient registration for optical tracker-free robotic fracture reduction surgery.

BACKGROUND AND OBJECTIVE: Image-guided robotic surgery for fracture reduction is a medical procedure in which surgeons control a surgical robot to align the fractured bones by using a navigation system that shows the rotation and distance of bone movement. In such robotic surgeries, it is necessary to estimate the relationship between the robot and patient (bone), a task known as robot-patient registration, to realize the navigation. Through the registration, a fracture state in real-world can be simulated in virtual space of the navigation system. METHODS: This paper proposes an approach to realize robot-patient registration for an optical-tracker-free robotic fracture-reduction system. Instead of the optical tracker which is a three-dimensional position localizer, X-ray images are used to realize the robot-patient registration, combining the relationship of both the robot and patient with regards to C-arm. The proposed method consists of two steps of registration, where initial registration is followed by refined registration which adopts particle swarm optimization with the minimum cross-reprojection error based on bidirectional X-ray images. To address the unrecognizable features due to interference between the robot and bone, we also developed attachable robot features. The allocated robot features could be clearly extracted from the X-ray images, and precise registration could be realized through the particle swarm optimization. RESULTS: The proposed method was evaluated in phantom and ex-vivo experiments involving a caprine cadaver. For the phantom experiments, the average translational and rotational errors were 1.88 mm and 2.45°, respectively, and the corresponding errors in the ex vivo experiments were 2.64 mm and 3.32° The results demonstrated the effectiveness of the proposed robot-patient registration. CONCLUSIONS: The proposed method enable to estimate the three-dimensional relationship between fractured bones in real-world by using only two-dimensional images, and the relationship is accurately simulated in virtual reality for the navigation. Therefore, a reduction procedure for successful treatment of bone fractures in image-guided robotic surgery can be expected with the aid of the proposed registration method.

Evaluation of bone grafting for treatment of low-grade chondrosarcoma of long bones.

OBJECTIVE: To retrospectively analyze the biological compatibility and oncologic outcomes of autogenous, allogeneic, or combined bone grafting. METHODS: From April 2000 to December 2016, 37 patients with histologically confirmed low-grade intramedullary chondrosarcoma of the long bones at Kyungpook National University Hospital were enrolled in this retrospective study. All 37 patients underwent intralesional curettage (with or without cryotherapy) followed by bone grafting. Among the 24 patients who underwent cryotherapy, 13 were treated by prophylactic internal fixation (10 in the femur, 1 in the tibia, and 2 in the humerus). Thirteen patients underwent the same treatment without cryotherapy, whereas 12 did not undergo preventive internal fixation. RESULTS: A single intraoperative fracture was managed by plate fixation. One patient who underwent cryotherapy and internal fixation developed a fracture distal to the operation site 25 days after surgery, and this fracture was repaired with a long plate. None of the 37 patients showed any recurrence or metastasis. CONCLUSIONS: Adequate intralesional curettage (with or without cryosurgery) combined with bone grafting using autogenous and allogeneic bone chips was effective for the treatment of low-grade intramedullary chondrosarcoma. Therefore, prophylactic internal fixation using a plate is recommended in the cryotherapy of definite cortical invasion in weight-bearing bones.

Conventional bicortical pin substitution with a novel unicortical pin in external fixation: A biomechanical study.

INTRODUCTION: As most patients with polytrauma or open fractures are converted from temporary external fixation to definite stabilization, the prevention of complications such as infection is especially important. To overcome the high risk of infection associated with the use of the conventional bicortical pin for temporary external fixation, the authors developed a novel unicortical pin and analyzed it in a biomechanical study. METHODS: The unicortical pin consisted of an inner screw, purchasing the cortical bone, and an outer sleeve with 6 spikes. A bicortical pin was used for the purpose of comparison. A fracture gap model was stabilized using a monoplanar configuration. Both the unicortical pins (Uni group) and bicortical pins (Bi group) underwent axial compressive and torsional load testing using a servo-hydraulic testing machine. Stiffness, load to failure, and mode of failure were documented. RESULTS: Stiffness and load to failure of the Uni group (average, 40.5 N/mm and 1098.4 N, respectively) were greater than that of the Bi group (average, 33.7 N/mm and 968.6 N, respectively) in the axial compressive load test (P = 0.008 and 0.032). Stiffness and load to failure of the Uni group (average, 1.2 Nm/degree and 1.7 Nm, respectively) were also significantly higher than those of the Bi group (average, 0.8 Nm/degree and 0.6 Nm, respectively) in the torsional load test (P = 0.008 and 0.016). All pins in the Bi group were bent at the pin-synthetic bone interface without synthetic bone failure. Contrarily, the Uni group did not show any pin bending or failure. However, in the axial compression test, partial cracks in the synthetic bone were found at the interface with spikes in the outer shell. In addition, in the torsion test, incomplete fractures were seen through the inner screws' holes. CONCLUSION: Compared with the conventional bicortical pin, the newly designed unicortical pin significantly increased fracture stability under both axial compressive and torsional loads. The unicortical pin can be considered an alternative biomechanical solution to obtain adequate stability when performing external fixation of fractures.

Pullout strength of pedicle screws using cadaveric vertebrae with or without artificial demineralization.

OBJECTIVES: To evaluate the differences in the pullout strength and displacement of pedicle screws in cadaveric thoracolumbar vertebrae with or without artificial demineralization. METHODS: Five human lumbar and five thoracic vertebrae from one cadaver were divided into two hemivertebrae. The left-side specimens were included in the simulated osteopenic model group and the right-side bones in a control group. In the model group, we immersed each specimen in HCl (1 N) solution for 40 minutes. We measured bone mineral density (BMD) using dual-energy X-ray absorptiometry and quantitative computerized tomography. We inserted polyaxial pedicle screws into the 20 pedicles of the cadaveric lumbar and thoracic spine after measuring the BMD of the 2 hemivertebrae of each specimen. We measured the pullout strength and displacement of the screws before failure in each specimen using an Instron system. RESULTS: The average pullout strength of the simulated osteopenic model group was 76% that of the control group. In the control and model groups, the pullout strength was 1678.87±358.96 N and 1283.83±341.97 N, respectively, and the displacement was 2.07±0.34 mm and 2.65±0.50 mm, respectively (p<.05). We detected positive correlations between pullout strength and BMD in the control group and observed a negative correlation between displacement and BMD in the model group. CONCLUSIONS: By providing an anatomically symmetric counterpart, the human cadaveric model with or without demineralization can be used as a test bed for pullout tests of the spine. In the simulated osteopenic model group, pullout strength was significantly decreased compared with the untreated control group. CLINICAL SIGNIFICANCE: Decreased bone mineral density may significantly reduce the pullout strength of a pedicle screw, even though the range is osteopenic rather than osoteoporotic.

Periostin is a novel histological biomarker for the diagnosis of chondroid tumor.

BACKGROUND: The chondroid tumor is generally classified into three types, enchondroma, low-grade chondrosarcoma, and high-grade chondrosarcoma. A histological evaluation of a biopsy sample is the best predictor of the clinical course in most patients with carcinomas or sarcomas. Sometimes serological or molecular markers are used as prediction markers, but there has been no reliable marker for chondroid tumor diagnosis. Clinical and radiological, but not histological features, are still used in the diagnosis and staging of chondroid tumors. During a histopathological diagnosis, it has been difficult to distinguish between benign enchondroma and low-grade chondrosarcoma. To allow for more accurate treatments, new histological biomarkers for the differential diagnosis are needed. METHODS: Twenty-eight cases of enchondromas and thirty-three cases of low-grade chondrosarcoma were selected. Thirteen cases of non-tumorous cartilage were used for the control group, who underwent artificial joint surgery for degenerative arthritis. Surgically removed tissue specimens were formalin-fixed paraffin-embedded and hematoxylin and eosin (H&E) and immunohistochemistry (IHC) stains were performed. RESULTS: Periostin was expressed in chondroid tumors but not in the normal cartilage. Periostin was observed via immunostaining in the cytoplasm but not in the extracellular matrix of enchondroma tissue, and was observed in the cytoplasm and extracellular matrix of low-grade chondrosarcoma. The sensitivity and specificity of these stains were 93.9% and 96.4%, respectively. CONCLUSIONS: Based on these results, we suggest that periostin could be used as a novel prognostic marker to distinguish between enchondroma and low-grade chondrosarcoma.

Generative approach for data augmentation for deep learning-based bone surface segmentation from ultrasound images.

PURPOSE: Precise localization of cystic bone lesions is crucial for osteolytic bone tumor surgery. Recently, there is a move toward ultrasound imaging over plain radiographs (X-rays) for intra-operative navigation due to the radiation-free and cost-effectiveness of the modality. In this process, the intra-operative bone model reconstructed from the segmented ultrasound image is registered with the pre-operative bone model. Deep learning approaches have recently shown remarkable success in bone surface segmentation from ultrasound images. However, to train deep learning models effectively with limited dataset size, data augmentation is essential. This study investigates the applicability of the generative approach for data augmentation as well as identifies standard data augmentation approaches for bone surface segmentation from ultrasound images. METHODS: The generative approach we used in our work is based on Pix2Pix image-to-image translation network. We have proposed a multiple-snapshot approach, which mitigates the uni-modal deterministic output issue in the Pix2Pix network without using any complex architecture and training process. We also identified standard data augmentation approaches necessary for ultrasound bone surface segmentation through experiments. RESULTS: We have evaluated our networks using 800 ultrasound images from trained regions (humerus bone) and 1200 ultrasound images from untrained regions (tibia and femur bones) using four different augmentation approaches. The results show that the generative augmentation approach has a positive impact on accuracy in both trained (+ 4.88%) and untrained regions (+ 25.84%) compared to using only standard augmentations. Moreover, compared to standard augmentation approaches, the addition of the generative augmentation approach also showed a similar trend in both trained (+ 8.74%) and untrained (+ 11.55%) regions. CONCLUSION: Generative approaches are very beneficial for data augmentation, where limited dataset size is prevalent, such as ultrasound bone segmentation. The proposed multiple-snapshot Pix2Pix approach has the potential to generate multimodal images, which enlarges the dataset considerably.

Fluoroscopic images-based aiming and targeting system with two line lasers for insertion guidance of interlocking screw.

PURPOSE: Minimally invasive surgery is widely used for managing fractures; however, it is difficult to determine the exact screwing position of intramedullary nails inserted into bone. To address this problem, we developed the aiming and targeting system by laser (ATLAS) using two line lasers to mark the position of the surgical tool directly on the skin. METHODS: ATLAS consists of a laser module, controller, personal computer, and display device. The laser module is fixed to the intensifier side of the C-arm. Calibration with dedicated markers is required prior to using the system. After calibration, the laser modules can mark the selected point on a fluoroscopic image acquired with the C-arm as the intersection of the two line lasers on the skin. RESULTS: To verify the effectiveness of ATLAS, marking accuracy was measured. The average control error of the device itself was 0.57 mm. In the experimental setting using C-arm fluoroscopy, the accuracy was within 1.5 mm at 23 of the 25 measurement points and within 3 mm at the remaining two points. CONCLUSION: ATLAS shows the corresponding points in real space with respect to fluoroscopic images using cross-points of lasers. The proposed method is clinically useful to aid the insertion of interlocking screws in minimally invasive surgeries for bone fractures. We believe that ATLAS enables more accurate marking through C-arm fluoroscopy and is more convenient, and it can thus be applied in various orthopedic surgeries.

Additional fixation of medial plate over the unstable lateral locked plating of distal femur fractures: A biomechanical study.

INTRODUCTION: Lateral locked plating is a standard treatment option for distal femur fractures. However, the unstable conditions after lateral locked plating are increasing. The objective of this study was to investigate the biomechanical strength of additional medial plate fixation over the unstable lateral locked plating of distal femur fractures. MATERIALS AND METHODS: A distal femur fracture model (AO/OTA 33-A3) was created with osteotomies in the composite femur. Three study groups consisting of 6 specimens each were created for single-side lateral locked plating with 6 distal locking screws (LP-6), single-side lateral locked plating with 4 distal locking screws (LP-4), and additional medial locked plating on LP-4 construct (DP-4). A compressive axial load (10 mm/min) was applied in the failure test. Mode of failure, load to failure, and ultimate displacement were documented. RESULTS: All single-side lateral locked plating (LP-4 and LP-6) showed plate bending at the fracture gap, while none of the DP-4 showed plate bending at the fracture gap. Load to failure of DP-4 (mean 5522 N) was 17.1% greater than that of LP-6 (mean 4713.3 N, p < 0.05) and 29.2% greater than that of LP-4 (mean 4273.2 N, p < 0.05). Ultimate displacement of DP-4 (mean 5.6 mm) was significantly lower than that of LP-6 (mean 8.8 mm, p < 0.05) and LP-4 (mean 9.1 mm, p < 0.05). CONCLUSIONS: Additional fixation of medial plate significantly increased the fracture stability in distal femur fractures fixed with the lateral locked plating. Especially in the clinical situations where sufficient stability cannot be provided at the distal segment, the medial plate may be considered as a useful biomechanical solution to obtain adequate stability for fracture healing.

Evaluation of Accuracy of a Three-Dimensional Printed Model in Open-Wedge High Tibial Osteotomy.

The purpose of this study was to evaluate the usefulness of a three-dimensional (3D) printed model for open-wedge high tibial osteotomy (HTO). This study retrospectively evaluated 20 patients with medial knee osteoarthritis and varus deformity. Between October 2015 and July 2016, the patients underwent open-wedge HTO using a 3D printed model. The mean age of patients was 55.2 years (range, 51-60 years). The mean preoperative mechanical femorotibial angle (mFTA) was varus 7.8 degrees (range, varus 4.7-11.6 degrees). After measuring the target angle using full-length lower limb weight-bearing radiography, the osteotomy was simulated using 3D images obtained from computed tomography (CT) with the 3D Slicer program. On the basis of the simulated osteotomy section and the target angle, the model was then designed and printed. Open-wedge HTO was then performed by applying the 3D printed model to the opening gap. The accuracy of osteotomy and the change in posterior tibial slope (PTS) angle were evaluated. The weight-bearing line on the tibial plateau was corrected from a preoperative mean of 19.5 ± 9.8% to a postoperative mean of 63.1 ± 6.1% (p < 0.001). The postoperative values were not statistically significantly different from the preoperative target points (p = 0.688). The mFTA was corrected to a postoperative mean of valgus 3.8 ± 1.4 degrees. The PTS angle showed no significant change (p = 0.256). A 3D printed model using CT may be useful for preoperative planning of open-wedge HTO. Satisfactory correction can be obtained without a change in the PTS.

More accurate correction can be obtained using a three-dimensional printed model in open-wedge high tibial osteotomy.

PURPOSE: The purpose of this study was to compare the accuracy of the preoperative planning method using a three-dimensional (3D) printed model with that of a method using picture archiving and communication system (PACS) images in high tibial osteotomy (HTO). METHODS: Patients who underwent HTO using a 3D printed model (20 patients) and a method based on PACS images (20 patients) from 2012 to 2016 were compared. After obtaining the correction angle, in the 3D printed method, the wedge-shaped 3D printed model was designed. The PACS method used preoperative radiographs. The accuracy of HTO for each method was compared using radiographs obtained at the first postoperative year. The preoperative and postoperative posterior tibial slope angles were also compared. RESULTS: The weight-bearing line was corrected 21.2 ± 11.8% from preoperatively to 61.6 ± 3.3% postoperatively in the 3D group and from 19.4 ± 12.3% to 61.3 ± 8.1% in the PACS group. The mean absolute difference with the target point was lower in the 3D group (2.3 ± 2.5) than in the PACS group (6.2 ± 5.1; p = 0.005). The number of patients in an acceptable range was higher in the 3D group than in the PACS group. The posterior tibial slope angle was not significantly different in the 3D group (8.6°-8.9°), but was significantly different in the PACS group (9.9°-10.5°, p = 0.042). CONCLUSIONS: In open-wedge HTO, a more accurate correction for successful results could be obtained using the 3D printed model. LEVEL OF EVIDENCE: IV.

Minimally invasive plate augmentation in the treatment of long-bone non-unions.

INTRODUCTION: Exchange nailing is most acceptable for treating hypertrophic non-union of the long bones, requiring the removal of previously fixed implant. However, its main effect of mechanical stabilization is controversial in non-isthmal area. We hypothesized that minimally invasive plate augmentation over the non-union site may have a better option, without the need of bone grafting or removing pre-existing implants. MATERIALS AND METHODS: Seventeen patients with hypertrophic non-union of the long bones between 2010 and 2014 on radiography who previously underwent intramedullary (IM) nailing or plate osteosynthesis for long-bone fractures were included. A locking compression plate was inserted with at least three mono- or bicortical screws at each proximal and distal segment. Broken or loosened interlocking screws of IM nail were simultaneously re-fixed. Fracture site exposure, pre-fixed implant removal, and bone grafting were not performed. We investigated whether union occurred and analyzed functional outcomes and complications. RESULTS: Eleven femoral and six tibial non-unions were prospectively included. In the pre-existing implants, 13 nails and 4 plates were found. All cases achieved union at a mean 22.7 weeks. One case of superficial infection was managed with oral antibiotics. Deep infection or implant failure did not occur. CONCLUSIONS: Minimally invasive plate augmentation can achieve additional stability and promote healing of hypertrophic non-union of the long bones. When indicated, this technique is the least invasive alternative to exchange nailing and reduces surgical risks in the treatment of diaphyseal non-union.

Angular deformity correction by guided growth in growing children: Eight-plate versus 3.5-mm reconstruction plate.

BACKGROUND: Guided growth using the eight-plate (8-plate) is the most commonly used method to correct angular deformities in children; however, implant failure has been reported. Recently, the 3.5-mm reconstruction plate (R-plate) has been used as an alternative option for guided growth; however, hardware prominence has been problematic. This study aimed to compare the coronal angular deformity correction results of guided growth between relatively thin 8-plates with cannulated screws and thick R-plates with solid screws. METHODS: Thirty-nine physes (24 distal femoral, 15 proximal tibial) in 20 patients underwent hemiepiphysiodesis using 8-plates, and 61 physes (40 distal femoral, 21 proximal tibial) in 35 patients underwent hemiepiphysiodesis using R-plates. Coronal angular corrections were measured and compared preoperatively, and after the completion of corrections. Amounts and rates of correction and complications were compared between the groups. RESULTS: Mean body mass index was 18.7 kg/m2 in the 8-plate group, and 22.7 kg/m2 in the R-plate group. Angular correction was achieved in all deformities at a mean of 13.7 months and 19.7 months in the 8-plate and the R-plate group, respectively. The mean corrected mechanical lateral distal femoral angle was 9.0° in the 8-plate group, and 9.9° in the R-plate group (P = 0.55). The mean corrected medial proximal tibial angle was 7.1° in the 8-plate group, and 9.0° in the R-plate group (P = 0.07). The mean rates of angular correction were also not significantly different in the distal femur (1.03°/month vs. 0.77°/month, P = 0.2) and the proximal tibia (0.66°/month vs. 0.63°/month, P = 0.77). There was one superficial infection in each group, and one case of implant failure in the R-plate group. Two rebound deformities were observed and needed repeat hemiepiphysiodesis. Permanent physeal arrest was not observed in this series.

Malalignment after minimally invasive plate osteosynthesis in distal femoral fractures.

INTRODUCTION: Although minimally invasive plate osteosynthesis (MIPO) is a preferred operative treatment for fractures of the distal femur, malalignment is a significant concern because of indirect reduction of the fracture. The purpose of this study, therefore, was to evaluate radiologic alignment after MIPO for distal femoral fractures. PATIENTS AND METHODS: Of the 138 patients with fracture of the distal femur who underwent MIPO, we enrolled 51 patients in whom bilateral rotational alignment could be assessed by postoperative computed tomography (CT). The patients included 32 men and 19 women, with a mean age of 54.3 years. Thirteen patients had femoral shaft fractures (according to the AO/OTA classification: 32-A, n=2; 32-B, n=6; 32-C, n=5), whereas 38 patients had distal femoral fractures (33-A, n=7; 33-C, n=31). Coronal and sagittal alignments were assessed using simple radiography, whereas rotational alignment was assessed using CT. According to the difference between the affected and unaffected sides, we divided the patients into satisfactory and unsatisfactory groups (reference point of 8°, using Handolin's classification). Thereafter, we determined which factors can lead to malalignment, including fracture location (distal femoral shaft fracture or metaphyseal fracture), fracture pattern (simple fracture, n=15; complex fractures, n=36 patients), coronal and sagittal alignments, and combined ipsilateral long bone fractures. RESULTS: Coronal and sagittal alignment were satisfactory in 96.2% (average, 2.8°) and 98% (average, 2.2°), respectively, whereas the rotational alignment was satisfactory in 56.9% of patients. Leg length discrepancy was satisfactory in 92.3% of the patients (average, 10.9mm). Concerning rotational malalignment, an unsatisfactory result was obtained in 48.6% of subjects with complex fractures and 26.7% of subjects with simple fractures (p=0.114). No significant correlation was noted between the angular deformity in the coronal and sagittal planes and the degree of rotational alignment (p=0.607 and 0.774, respectively). CONCLUSIONS: Regardless of the fracture pattern, rotational malalignment may occur at an extremely high rate after MIPO for fractures of the distal femur.

Open wedge high tibial osteotomy using three-dimensional printed models: Experimental analysis using porcine bone.

BACKGROUND: The purpose of this study was to evaluate the usefulness of three-dimensional (3D) printed models for open wedge high tibial osteotomy (HTO) in porcine bone. METHODS: Computed tomography (CT) images were obtained from 10 porcine knees and 3D imaging was planned using the 3D-Slicer program. The osteotomy line was drawn from the three centimeters below the medial tibial plateau to the proximal end of the fibular head. Then the osteotomy gap was opened until the mechanical axis line was 62.5% from the medial border along the width of the tibial plateau, maintaining the posterior tibial slope angle. The wedge-shaped 3D-printed model was designed with the measured angle and osteotomy section and was produced by the 3D printer. The open wedge HTO surgery was reproduced in porcine bone using the 3D-printed model and the osteotomy site was fixed with a plate. Accuracy of osteotomy and posterior tibial slope was evaluated after the osteotomy. RESULTS: The mean mechanical axis line on the tibial plateau was 61.8±1.5% from the medial tibia. There was no statistically significant difference (P=0.160). The planned and post-osteotomy correction wedge angles were 11.5±3.2° and 11.4±3.3°, and the posterior tibial slope angle was 11.2±2.2° pre-osteotomy and 11.4±2.5° post-osteotomy. There were no significant differences (P=0.854 and P=0.429, respectively). CONCLUSION: This study showed that good results could be obtained in high tibial osteotomy by using 3D printed models of porcine legs.

Elastic nailing of tibia shaft fractures in young children up to 10 years of age.

INTRODUCTION: Although tibia shaft fractures in children usually have satisfactory results after closed reduction and casting, there are several surgical indications, including associated fractures and soft tissue injuries such as open fractures. Titanium elastic nails (TENs) are often used for pediatric tibia fractures, and have the advantage of preserving the open physis. However, complications such as delayed union or nonunion are not uncommon in older children or open fractures. In the present study, we evaluated children up to 10 years of age with closed or open tibial shaft fractures treated with elastic nailing technique. METHODS: A total of 16 tibia shaft fractures treated by elastic nailing from 2001 to 2013 were reviewed. The mean patient age at operation was 7 years (range: 5-10 years). Thirteen of 16 cases were open fractures (grade I: 4, grade II: 6, grade IIIA: 3 cases); the other cases had associated fractures that necessitated operative treatments. Closed, antegrade intramedullary nailing was used to insert two nails through the proximal tibial metaphysis. All patients were followed up for at least one year after the injury. Outcomes were evaluated using modified Flynn's criteria, including union, alignment, leg length discrepancies, and complications. RESULTS: All fractures achieved union a mean of 16.1 weeks after surgery (range: 11-26 weeks). No patient reported knee pain or experienced any loss of knee or ankle motion. There was a case of superficial infection in a patient with grade III open fracture. Three patients reported soft tissue discomfort due to prominent TEN tips at the proximal insertion site, which required cutting the tip before union or removing the nail after union. At the last follow-up, there were no angular or rotational deformities over 10° in either the sagittal or coronal planes. With the exception of one case with an overgrowth of 15 mm, no patient showed shortening or overgrowth exceeding 10mm. Among final outcomes, 15 were excellent and 1 was satisfactory. SUMMARY: Even with open fractures or soft tissue injuries, elastic nailing can achieve satisfactory results in young children, with minimal complications of delayed bone healing, or infection.

A preliminary study on surgical navigation for epiduroscopic laser neural decompression.

Epiduroscopic laser neural decompression is an emerging therapeutic modality to treat lumbar spine pathologies including chronic low back pain, spinal stenosis, and disk herniation via catheter insertion followed by laser ablation of the lesion. Despite the efficacy of epiduroscopic laser neural decompression, excessive radiation doses due to fluoroscopy during epiduroscopic laser neural decompression have limited its widespread application. To address the issue, we propose a surgical navigation system to assist in epiduroscopic laser neural decompression procedures using radiation-free image guidance. An electromagnetic tracking system was used as the basic modality to track the internal location of the surgical instrument with respect to the patient body. Patient-to-image registration was carried out using the point-based registration method to determine the transformation between the coordinate system of the patient and that of the medical images. We applied the proposed system in epiduroscopic laser neural decompression procedures to assess its effectiveness, and the outcomes confirmed its clinical feasibility. To the best of our knowledge, this is a report on the first surgical navigation applied for epiduroscopic laser neural decompression procedure.

Development of femoral bone fracture model simulating muscular contraction force by pneumatic rubber actuator.

In femoral fracture reduction, orthopedic surgeons must pull distal bone fragments with great traction force and return them to their correct positions, by referring to 2D-fluoroscopic images. Since this method is physically burdensome, the introduction of robotic assistance is desirable. While such robots have been developed, adequate control methods have not yet been established because of the lack of experimental data. It is difficult to obtain accurate data using cadavers or animals because they are different from the living human body's muscle characteristics and anatomy. Therefore, an experimental model for simulating human femoral characteristics is required. In this research, human muscles are reproduced using a McKibben-type pneumatic rubber actuator (artificial muscle) to develop a model that simulates typical femur muscles using artificial muscles.

A histomorphometric study of cellular layers after hemiepiphyseal stapling on the physeal plate in rabbits.

BACKGROUND: Epiphyseal stapling has been widely used to correct angular deformity. The mechanism, however, has not been well determined. To determine the effect of temporary hemiepiphyseal stapling on the cellular layers of the physis, a histomorphometric study was performed using immature rabbits. METHODS: Distal lateral epiphyseal stapling of the right femur was performed on 6-week-old New Zealand white rabbits. Thirty rabbits were randomly assigned to five groups, and six rabbits in each group were analyzed weekly for up to 5 weeks. RESULTS: The distal femur was deformed into the valgus, and the anatomical lateral distal femoral angle decreased with the passage of time. In the sequential histomorphometry of the operated physeal plate, the area ratio of each layer, compared to the control side, decreased every week. The total area of the physeal plate had decreased up to 60 % at the 5th week compared to the area of the 1st week, and the area of the proliferative layer decreased by the greatest amount among the three layers. CONCLUSIONS: Our findings suggest that the proliferation of chondrocytes seemed to be more suppressed by the compression of the stapling, thereby slowing the growth rate, although hypertrophy of the chondrocytes was also suppressed.