Computational modeling of the cephalic arch with jugulocephalic vein variant predicts hemodynamic profiles in patients with brachiocephalic fistula.

BACKGROUND: The cephalic vein is often used in for arteriovenous fistula creation; however, the cephalic vein variation is common. This study will propose new theoretical explanations for a new discovered variation of cephalic vein draining into external jugular vein with "T-junction" shape by means of 3D computational hemodynamic modeling, which may provide reference for clinical practice. METHODS: The precise measurements were conducted for the variant right cephalic vein draining into external jugular vein and for a normal right cephalic vein as a control. After processing the anatomical data, 3D geometrical model was reconstructed. Then, the influent field inside the variant jugulocephalic vein was mathematically modeled to get a detailed description of hemodynamic environment. RESULTS: The anatomical parameters of the "T-junction" jugulocephalic vein variant were much more different from the normal right cephalic vein. The wall shear stress of variant cephalic vein at the corresponding position was higher and changed more rapidly than that of normal cephalic vein. The shear rate contour lines are disordered in several areas of the variant cephalic vein, indicating that the hemodynamic parameters in these areas are unstable. The hemodynamic characteristics at the confluence of the variant cephalic vein are more complex, with more areas where hemodynamic parameters are disrupted. CONCLUSIONS: The variation of cephalic arch in a "T-junction" with external jugular vein largely altered the fluid dynamics, especially in hemodialysis patients with brachiocephalic fistula in terms of the simulating flow in 3D computational model. This computational model provides hemodynamic profiles for stabilizing or modulating fluid dynamics in patients with jugulocephalic vein variant after brachiocephalic fistula.

The Contrastive Network With Convolution and Self-Attention Mechanisms for Unsupervised Cell Segmentation.

Deep learning for cell instance segmentation is a significant research direction in biomedical image analysis. The traditional supervised learning methods rely on pixel-wise annotation of object images to train the models, which is often accompanied by time-consuming and labor-intensive. Various modified segmentation methods, based on weakly supervised or semi-supervised learning, have been proposed to recognize cell regions by only using rough annotations of cell positions. However, it is still hard to achieve the fully unsupervised in most approaches that the utilization of few annotations for training is still inevitable. In this article, we propose an end-to-end unsupervised model that can segment individual cell regions on hematoxylin and eosin (H&E) stained slides without any annotation. Compared with weakly or semi-supervised methods, the input of our model is in the form of raw data without any identifiers and there is no need to generate pseudo-labelling during training. We demonstrated that the performance of our model is satisfactory and also has a great generalization ability on various validation sets compared with supervised models. The ablation experiment shows that our backbone has superior performance in capturing object edge and context information than pure CNN or transformer under our unsupervised method.

Primary Cooperative Application of a LARS® Tube and 3D-Printed Prosthesis for Reconstruction of the Distal Radius after en bloc Resection of Giant Cell Tumor of Bone: A Comparative Retrospective Study.

OBJECTIVE: Using a fibula autograft (FA) to reconstruct defects after en bloc resection of giant cell tumor of bone (GCTB) in the distal radius is classic but has high complication rates. We describe a novel reconstruction method employing the cooperative application of LARS® and a 3D-printed prosthesis (L-P) and investigate whether it improves postoperative outcomes. METHODS: From April 2015 to August 2022, 14 patients who underwent the cooperative L-P reconstruction method after en bloc resection of distal radial GCTBs and 31 patients who received FA reconstruction were enrolled as two retrospective cohorts in this comparative study. The properties of the implants and critical surgical techniques were elaborated in the L-P group. Preoperative function, intraoperative data, and postoperative clinical, functional, and radiographic outcomes of all patients were recorded and compared between the two groups. The grip strength and range of wrist motion, including extension, flexion, radial deviation, and ulnar deviation, were measured. The Mayo modified wrist and Musculoskeletal Tumor Society scores were chosen to assess wrist function and surgical functional outcomes, respectively. Kaplan-Meier curves were generated to analyze the significant differences in complication rates and implant survival between the two groups. RESULTS: In both groups, all 45 patients underwent the operation without complication with similar average osteotomy lengths and bleeding volumes, while a shorter operative duration was achieved in the L-P group (201.43 ± 22.87 min vs. 230.16 ± 51.44 min, P = 0.015). At a mean follow-up of 40.42 ± 18.43 months (range, 14-72 months), both reconstruction methods effectively ameliorated postoperative function. Patients who received L-P showed higher postoperative modified Mayo wrist scores (81.43 ± 5.49 vs. 71.13 ± 16.10, P = 0.003), Musculoskeletal Tumor Society scores (27.64 ± 1.34 vs. 25.06 ± 2.95, P = 0.004), and grip strength on the normal side (68.71% ± 8.00% vs. 57.81% ± 12.31%, P = 0.005) than the FA group. Better wrist extension (63.21° ± 8.99° vs. 45.32° ± 14.53°, P < 0.001) and flexion (45.36° ± 7.90° vs. 30.48° ± 12.07°, P < 0.001) were also observed in the L-P group. The complication rate was significantly higher in the FA group (29/31, 93.55%) than in the L-P group (1/14 7.14%, P < 0.001). The L-P group showed higher implant survival than the FA group, but the difference was not statistically significant. CONCLUSION: The cooperative application of LARS® and 3D-printed prostheses is an effective modality for reconstructing musculoskeletal defects after en bloc resection of distal radial GCTBs, which can improve functional outcomes, diminish complication rates, and promote wrist joint stability and motion.

Reconstruction of massive bone defects after femoral tumor resection using two new-designed 3D-printed intercalary prostheses: a clinical analytic study with the cooperative utilization of multiple technologies.

BACKGROUND: To reconstruct massive bone defects of the femoral diaphysis and proximal end with limited bilateral cortical bone after joint-preserving musculoskeletal tumor resections, two novel 3D-printed customized intercalary femoral prostheses were applied. METHODS: A series of nine patients with malignancies who received these novel 3D-printed prostheses were retrospectively studied between July 2018 and November 2021. The proximal and diaphyseal femur was divided into three regions of interest (ROIs) according to anatomic landmarks, and anatomic measurements were conducted on 50 computed tomography images showing normal femurs. Based on the individual implant-involved ROIs, osteotomy level, and anatomical and biomechanical features, two alternative 3D-printed prostheses were designed. In each patient, Hounsfield Unit (HU) value thresholding and finite element analysis were conducted to identify the bone trabecula and calcar femorale and to determine the stress distribution, respectively. We described the characteristics of each prosthesis and surgical procedure and recorded the intraoperative data. All patients underwent regular postoperative follow-up, in which the clinical, functional and radiographical outcomes were evaluated. RESULTS: With the ROI division and radiographic measurements, insufficient bilateral cortical bones for anchoring the traditional stem were verified in the normal proximal femur. Therefore, two 3D-printed intercalary endoprostheses, a Type A prosthesis with a proximal curved stem and a Type B prosthesis with a proximal anchorage-slot and corresponding locking screws, were designed. Based on HU value thresholding and finite element analysis, the 3D-printed proximal stems in all prostheses maximally preserved the trabecular bone and calcar femorale and optimized the biomechanical distribution, as did the proximal screws. With the 3D-printed osteotomy guide plates and reaming guide plates, all patients underwent the operation uneventfully with a satisfactory duration (325.00 ± 62.60 min) and bleeding volume (922.22 ± 222.36 ml). In the follow-up, Harris Hip and Musculoskeletal Tumor Society scores were ameliorated after surgery (P < 0.001 and P < 0.001, respectively), reliable bone ingrowth was observed, and no major complications occurred. CONCLUSIONS: Two novel 3D-printed femoral intercalary prostheses, which achieved acceptable overall postoperative outcomes, were used as appropriate alternatives for oncologic patients with massive bone defects and limited residual bone and increased the opportunities for joint-preserving tumor resection. Several scientific methodologies utilized in this study may promote the clinical design proposals of 3D-printed implants.

[Application of LARS ligament combined with three-dimensional printed prosthesis in reconstruction of radial hemicarpal joint after tumor resection].

Objective: To investigate the effectiveness of LARS ligament and three-dimensional (3D) printed prosthesis on the combined reconstruction of radial hemicarpal joint after distal radius tumor resection. Methods: The clinical data of 12 patients with combined reconstruction of radial hemicarpal joint with LARS ligament and 3D printed prosthesis after distal radius tumor resection between September 2017 and March 2021 were retrospectively analyzed. There were 7 males and 5 females with an average age of 41.8 years (range, 19-63 years). There were 8 cases on the left side and 4 cases on the right side, and 10 cases of giant cell tumor of bone and 2 cases of osteosarcoma. The disease duration ranged from 1 to 20 months, with an average of 8.1 months. The osteotomy length, operation time, and intraoperative blood loss were recorded, and the wrist function was evaluated by Mayo wrist score and Musculoskeletal Tumor Society (MSTS) score before and after operation. The grip strength of the affected limb was expressed by the percentage of grip strength of the healthy upper limb, and the range of motion (ROM) of the wrist joint was measured, including extension, flexion, radial deviation, and ulnar deviation; the bone ingrowth and osseointegration at the bone-prosthesis interface of the wrist joint were observed by radiographic follow-up; the possible wrist complications were recorded. Results: All 12 patients successfully completed the operation. The osteotomy length was 5.0-10.5 cm (mean, 6.8 cm), and the operation time was 180-250 minutes (mean, 213.8 minutes). The intraoperative blood loss was 30-150 mL (mean, 61.7 mL). All patients were followed up 11-52 months (mean, 30.8 months). Radiographic follow-up showed that bone ingrowth and osseointegration at the bone-prosthesis interface were observed in all patients, and biological fixation was gradually achieved. During the follow-up, the stability, motor function, and ROM of the wrist joint were good. There was no complication such as arthritis, subluxation, prosthesis loosening, and infection, and no tumor recurrence and metastasis. At last follow-up, the Mayo score was 82.1±5.4, and MSTS score was 27.5±1.5, which were significantly improved when compared with those before operation (48.8±13.5, 16.4±1.4; t=-10.761, P<0.001; t=-26.600, P<0.001). The grip strength of the affected side was 59%-88% of that of the healthy side, with an average of 70.5%. The ROM of wrist joint were 55°-80° (mean, 65.42°) in extension, 35°-60° (mean, 44.58°) in flexion, 10°-25° (mean, 17.92°) in radial deviation, 10°-25° (mean, 18.33°) in ulnar deviation. Conclusion: The combined application of LARS ligament and 3D printed prosthesis is an effective way to reconstruct bone and joint defects after distal radius tumor resection. It can improve the function of wrist joint, reduce the incidence of complications, and improve the stability of wrist joint.

Transnasal Endoscopic and Transoral Approaches in the Biopsies of Ventral Atlas and Axis Vertebrae: A Comprehensive Retrospective Study for Preprocedural Scheme, Biopsy Procedure, Core Technique Analysis, Diagnostic Yield and Clinical Outcome.

OBJECTIVE: This study aims to describe and analyze the transoral and transnasal approaches for pathologies of the ventral atlas and axis vertebrae, which are considered technically challenging regions for diagnostic biopsy. METHODS: A series of transnasal endoscopic approach (TNA) and transoral approach (TOA) biopsies for the pathologies of the first and second cervical vertebrae were conducted and retrospectively analyzed from July 2014 to May 2021. The depth of the biopsy trajectory was measured on computed tomography images for all nine patients (eight males and one female with an average age of 58.11 ± 11.60 years), as were the coronal, sagittal, and vertical biopsy safe ranges. The characteristics of each lesion, including radiographic features, blood supply, and destruction of anterior or posterior vertebral body edges, were evaluated to guide the biopsy. Four biopsy core techniques (BCTs), including "lesion perforating", "aspiration", "cutting-and-scraping" and "biopsy forceps utilization" were elaborated in this study. The biopsy procedures and periprocedural precautions were demonstrated. Patient demographics, clinical data, lesion characteristics, diagnostic yield, and complications were recorded for each case. RESULTS: Eight TOA biopsies for the axis vertebral body and one TNA biopsy for the atlas anterior arch were successfully performed and yielded adequate pathologies. All biopsies were organized based on the preprocedural radiographic measurements, which showed that the average length of biopsy trajectory and coronal, sagittal, and vertical safe biopsy ranges were 85.00 ± 5.88, 20.63 ± 4.75, 16.25 ± 1.49, and 24.63 ± 2.26 mm, respectively, and these corresponding data were 95, 36, 9, and 26 mm in the TNA patient. Six osteolytic lesions (66.7%), one osteoblastic lesion (11.1%), and two mixed lesions (22.2%) were observed, among which seven lesions had a rich blood supply. Biopsy forceps and core needles were utilized to obtain samples in six and three patients, respectively. All the TNA and TOA biopsies were performed with cooperative application of multiple BCTs under compound anatomic and stereotactic navigations. Intraprocedural or postprocedural complications occurred in no patients who underwent the biopsy in the follow-up period (1-39 months). No significant differences were found between the preprocedural and postprocedural blood indexes and visual analogue scale scores. CONCLUSION: With a sophisticated preprocedural arrangement, cooperative application of BCTs, and careful periprocedural precautions, transnasal endoscopic and transoral biopsies are two feasible, efficient, and well-tolerated procedures that achieve satisfactory diagnostic yield, complication rate, and clinical outcome.

Discovery and Characterization of Intercondylar Transphyseal Complexes and their Oncological Significance in Transphyseal Extension of Pediatric Osteosarcoma.

OBJECTIVE: To explore whether there exist undiscovered transphyseal vasculature-canal compound structures in immature femurs and tibias, and reveal their potential oncological impact. METHODS: This investigation was divided into a morphological study and a clinical study. In the morphological part, a new-identified anatomic structure was investigated by using radiographical, anatomical, and histological methodologies. Twenty-eight 1-mm-slice thickness magnetic resonance images of pediatric knees were generated and 10 pediatric knees were dissected to verify the existence and universality, observe the radiographic and anatomic characteristics, and determined the located region of this structure. Hematoxylin-eosin staining, immunofluorescence, and angiography procedures were performed to illustrate its histological feature, molecular identification, and vascular origination, respectively. In the clinical part, 38 pediatric osteosarcoma patients were enrolled from January 2014 to December 2020. A descriptive clinical study including 13 typical participants was conducted to investigate the oncological significance of this new-identified structure. Meanwhile, the discrepancy in transphyseal osteosarcoma extension between different physeal regions was evaluated in a cross-sectional study. RESULTS: In the morphological study, we discovered a new-found vasculature-canal compound structure, intercondylar transphyseal complex (ITC), which originated from the middle genicular vessels, traversed the whole epiphysis, and breached the intact open physis in the immature proximal tibia or distal femur. The components of ITC included the juxta-articular, epiphyseal, and transphyseal segments of vessels, the canals that traverse the entire epiphysis and physis and enclosed the vessels, vascular foramina on articular facet and foramina-covered synovium. Depending on the location, ITCs can be divided into three types: femoral ITC, anterior tibial ITC, and posterior tibial ITC. Clinically, the ITC may facilitate intercondylar transphyseal sarcomatous dissemination without damaging the adjacent physeal cartilage. Compared to bilateral condylar physes, more osteosarcomas transgressed the open growth plates through intercondylar regions in which ITC was located (P = 0.022). CONCLUSION: As the "gap" on intact open physis, ITC, which is a new-identified compound structure in intercondylar regions of immature femur or tibia, may promote intercondylar transphyseal tumor extension. Moreover, the identification and characterization of ITC subvert some traditional comprehensions about physis and may provide novel perspectives for pediatric osteosarcomas.

Discovery of Lijianmin-Chengkun Complexes and Their Oncological Application in Osseous and Intraarticular Lesions Around the Knee.

Objective: This research aims to refresh the limited understanding about the canal and vascular structures within the epiphysis and metaphysis of the tibia and femur and their oncological significance. Methods: This study was started with characterization of a novel structure using radiographs and anatomic dissections, followed by a descriptive clinical study with 55 participants to investigate the effects of tumors on this novel discovery and a retrospective cohort study with 82 participants to investigate whether the structure would be a risk factor for tumor recurrence after the curettage of giant cell tumor of bone. Results: A new anatomical knee structure, the Lijianmin-Chengkun (LC) complex, was discovered in healthy adults, and its clinical implications were examined in this study. This new-found anatomical structure is composed of an epiphyseal and metaphyseal canal which surrounds a blood vessel, foramen, and foramen-covered synovium. All LC complexes showed similar radiographical, anatomical, and histological characteristics and were located within specific tibial and femoral intercondylar regions. These LC complexes seem to facilitate tumor residue and extension and may be a risk factor for tumor recurrence after curettage of femoral and tibial giant cell tumors (P = 0.031). Conclusion: The LC complexes are related to local tumor recurrence and bidirectional tumor dissemination between intraosseous and intraarticular regions. These findings have opened up a new perspective and may provide new targets for intervention in malignant and aggressive tumors around the knee joint.

Transnasal Endoscopic Biopsy Approach to Atlas Tumor with X-ray Assisted and Related Radiographic Measure.

OBJECTIVE: To develop an endoscopic transnasal approach to atlas tumors and study its practicability. METHODS: This article comprises two components: an illustrative case report and observational data on 50 volunteers. As to the case report, a 34 year old man presented with occipital pain for more than 3 months and underwent systematic investigation in Qilu Hospital of Shandong University. CT and MRI scans showed bony destruction in the craniovertebral junction (CVJ) suggestive of tumor. Via an endoscopic transnasal approach to the suspected atlas tumor through the inferior nasal meatus, a Gallini biopsy needle was used to obtain tissue for examination. The procedure was performed endoscopically with double orientation X-ray guidance and coaxial technology after establishing the shortest distance for the biopsy track and range of target tissue and was assisted by manual palpation. As to the observational data, 50 volunteers underwent atlas-related morphometric image measurement using gemstone CT equipment. Biopsy track angles, range for biopsy of the atlas and biopsy track distances were measured by a blinded operator on CT images. CASE REPORT: pathological examination of the biopsy resulted in diagnosis of a chordoma. There were no complications such as bleeding, infection or spinal cord injury. One month later, the patient underwent tumor resection and reconstruction in other hospital and the diagnosis of chordoma was confirmed by pathological examination of the resected specimen. Observational data: measurements obtained from CT scans of the 50 volunteers were as follows. Biopsy track angles: mean leaning inside angle 3.53° ± 0.39° and mean posterior slope angle 13.05° ± 1.39°. Range for atlas biopsy: transverse diameter 11.84 ± 1.24 mm and longitudinal diameter 9.67 ± 0.90 mm. Biopsy track distances: from atlas to nostril, and to anterior and posterior edges of the inferior turbinate mucosa were 94.52 ± 5.03 mm, 78.21 ± 4.63 mm, and 33.51 ± 3.13 mm, respectively. CONCLUSIONS: An endoscopic transnasal approach enables biopsy and diagnosis of tumors in the anterior arch of the atlas. Relevant measurements were obtained by assessing CT scans of 50 volunteers to assist operators to determine the effective and safe range for transnasal atlas biopsy.