An improvement of current hypercube pooling PCR tests for SARS-CoV-2 detection.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic can be effectively controlled by rapid and accurate identification of SARS-CoV-2-infected cases through large-scale screening. Hypercube pooling polymerase chain reaction (PCR) is frequently used as a pooling technique because of its high speed and efficiency. We attempted to implement the hypercube pooling strategy and found it had a large quantization effect. This raised two questions: is hypercube pooling with edge = 3 actually the optimal strategy? If not, what is the best edge and dimension? We used a C++ program to calculate the expected number of PCR tests per patient for different values of prevalence, edge, and dimension. The results showed that every edge had a best performance range. Then, using C++ again, we created a program to calculate the optimal edge and dimension required for pooling samples when entering prevalence into our program. Our program will be provided as freeware in the hope that it can help governments fight the SARS-CoV-2 pandemic.

Mathematical model of distal radius orientation.

Distal radius orientation is important in evaluating Colles' fracture. In most cases, the wrist was protected by a bandage, splint, or cast. Therefore, it was difficult for the radiology technician to take perfect anteroposterior and lateral view radiographs. In this study, we build a mathematical model and calculate the pronation angle needed to produce dorsal tilt, which is a volar tilt in a perfect lateral view radiograph. The formulas are all incorporated into Excel to facilitate usage.

Interleukin-6 transiently promotes proliferation of osteoclast precursors and stimulates the production of inflammatory mediators.

BACKGROUND: Clinical data and phenotypes of several in vivo models demonstrated that interleukin-6 (IL-6) is an essential positive regulator in inflammation-induced bone loss. However, how IL-6 affect bone resorption and the osteoclast differentiation remains in debate. In this study we elucidate the cellular responses of receptor activator of nuclear factor kappa-Β ligand (RANKL)-stimulated RAW254.7 macrophage, the process mimicking osteoclast differentiation, upon IL-6 co-stimulation. IL-6 is a pleiotropic cytokine triggering various cellular responses, ranging from pro-inflammatory responses, differentiation to proliferation or apoptosis in different cell types. Those cellular events in the RANKL-stimulated RAW cells were examined to understand how differentiating monocytic cells respond to IL-6 exposure. MATERIALS AND METHODS: Proliferation, apoptosis, differentiation and Pro-inflammatory responses of RANKL-stimulated RAW254.7 macrophage treated with or without IL-6 were measured by MTT assay, quantitative PCR assay of the expression of apoptotic genes, osteoclast differentiation markers, and pro-inflammatory genes, respectively. The results were collected from different time points in a 6-day differentiation period. Also, western blot on STAT3, ERK and AKT were also performed to investigate the IL-6 signaling in those cells. CONCLUSIONS: IL-6 triggered transient proliferation, but not apoptosis, in RANKL-stimulated RAW cells. Osteoclastogenesis was disrupted as the expression of essential genes for bone resorption were inhibited, and the osteoclast precursors maintained their undifferentiated phenotypes, with pro-inflammatory genes upregulated. Our results suggested that IL-6 interferes osteoclastogenesis. Additionally, IL-6 promote pro-inflammatory responses of monocytic cells and aggravate inflammation.

Full-endoscopic debridement and drainage treating spine infection and psoas muscle abscess.

BACKGROUND: In recent years, full-endoscopic debridement and drainage (FEDD) is gaining popularity treating spondylodiscitis. Comparing to tradition open surgery, FEDD possess many advantages including lower anesthesia risk and minimally invasiveness. In this study, we report our surgical technique of FEDD and preliminary clinical outcome in 34 consecutive patients with minimum 12 months follow-up. METHODS: In our institute, "early intervention and minimally invasive surgery" is our primary strategy to treat spine infection. Surgical approaches of FEDD include transforaminal and interlaminar technique. Selection of surgical approach depends on the location of spine infection. "Trocar-rotating technique" is a novel method to treat psoas muscle abscess. Additional instrumentation is suggested in complicated patients with unstable spinal segment. RESULTS: Since June 2016 to June 2018, 34 patients including 22 males and 12 females with average aged 62.3 years (21 to 82 years old) sustained spine infection were treated by FEDD. Twenty-eight patients belong to primary spondylodiscitis and 15 patients among them sustained concomitant psoas abscess. Five patients was post-operative infection and one patient was mixed infection including lumbar spondylodiscitis, psoas abscess and multi-level posterior epidural abscess. Positive culture was obtained in 27 patients (27/34=79%) while gram-positive cocci (Staphyloccocci and Streptoccoi) are the most frequent pathogen (67%). Infection was controlled in 28 patients (28/34=82%). Six patients were defined as treatment failure with infection recurrence, they underwent repeat FEDD surgery or open revision surgeries. There was no major intra-operative complications expect two patients sustained transient paresthesia and one instrument broken. Superficial wound infection was encountered in 2 patients and healed after local debridement. CONCLUSIONS: FEDD is a safe and effective procedure. We hope that, FEDD surgery will be the first-line surgery method to treat lumbar spine infection globally in the near future.

Implementation and performance evaluation of a drilling assistive device for distal locking of intramedullary nails.

Intramedullary nailing is a common treatment for long bone fractures. The nail might deform during implantation because of the shape of medullary cavity. Thus, surgeons take many X-ray images to position distal locking holes and check the drilling process. In this study, we developed a positioning algorithm with a passive or active (robot arm) assistive device for promptly positioning of distal locking holes and stably drilling guidance and support. Using the passive device, the surgeon could manually align the positioning probe with locking hole within 60 seconds based on 20 test cases. In 36 test cases, the active device aligned the positioning probe with locking hole automatically with average errors of 2.2 mm in position and 3.19° in direction. The passive device provides a reliable and low-cost solution for distal locking of intramedullary nails, while the active device is easy and friendly to use.

C-Arm Image-Based Surgical Path Planning Method for Distal Locking of Intramedullary Nails.

Due to the curvature of the bone marrow cavity, the intramedullary nail used in long bone fracture fixation can be deformed, causing displacement of the locking holes. In this study, an algorithm using only one C-arm image to determine the center positions and axial directions of locking holes was developed for drilling guidance. Based on conventional method that the axial direction of locking hole would be identified when locking hole contour is presented as a circle, the proposed method can locate the circle contour centroid by using one C-arm image including two elliptical contours. Then the two distal locking holes' axial direction and centers would be determined. Three experiments were conducted to verify the performance of the proposed algorithm, which are (1) computer simulation, (2) use of real intramedullary nails, and (3) actual drilling test with the bone model. The experimental results showed that the average error of the axial direction and center position were 0.62 ± 0.6°, 0.73 ± 0.53 mm (simulation) and 3.16 ± 1.36°, 1.10 ± 0.50 mm (actual nail), respectively. The last ten drilling test sets were completed successfully (with an average duration of 48 seconds). Based on the experimental results, the proposed algorithm was feasible for clinic applications.

Segmental correction of adolescent idiopathic scoliosis by all-screw fixation method in adolescents and young adults. minimum 5 years follow-up with SF-36 questionnaire.

BACKGROUND: In our institution, the fixation technique in treating idiopathic scoliosis was shifted from hybrid fixation to the all-screw method beginning in 2000. We conducted this study to assess the intermediate -term outcome of all-screw method in treating adolescent idiopathic scoliosis (AIS). METHODS: Forty-nine consecutive patients were retrospectively included with minimum of 5-year follow-up (mean, 6.1; range, 5.1-7.3 years). The average age of surgery was 18.5 ± 5.0 years. We assessed radiographic measurements at preoperative (Preop), postoperative (PO) and final follow-up (FFU) period. Curve correction rate, correction loss rate, complications, accuracy of pedicle screws and SF-36 scores were analyzed. RESULTS: The average major curve was corrected from 58.0 ± 13.0° Preop to 16.0 ± 9.0° PO(p < 0.0001), and increased to 18.4 ± 8.6°(p = 0.12) FFU. This revealed a 72.7% correction rate and a correction loss of 2.4° (3.92%). The thoracic kyphosis decreased little at FFU (22 ± 12° to 20 ± 6°, (p = 0.25)). Apical vertebral rotation decreased from 2.1 ± 0.8 PreOP to 0.8 ± 0.8 at FFU (Nash-Moe grading, p < 0.01). Among total 831 pedicle screws, 56 (6.7%) were found to be malpositioned. Compared with 2069 age-matched Taiwanese, SF-36 scores showed inferior result in 2 variables: physical function and role physical. CONCLUSION: Follow-up more than 5 years, the authors suggest that all-screw method is an efficient and safe method.

Instrumented posterior lumbar interbody fusion in adult spondylolisthesis.

UNLABELLED: It is unclear whether using artificial cages increases fusion rates compared with use of bone chips alone in posterior lumbar interbody fusion for patients with lumbar spondylolisthesis. We hypothesized artificial cages for posterior lumbar interbody fusion would provide better clinical and radiographic outcomes than bone chips alone. We assumed solid fusion would provide good clinical outcomes. We clinically and radiographically followed 34 patients with spondylolisthesis having posterior lumbar interbody fusion with mixed autogenous and allogeneic bone chips alone and 42 patients having posterior lumbar interbody fusion with implantation of artificial cages packed with morselized bone graft. Patients with the artificial cage had better functional improvement in the Oswestry disability index than those with bone chips alone, whereas pain score, patient satisfaction, and fusion rate were similar in the two groups. Postoperative disc height ratio, slip ratio, and segmental lordosis all decreased at final followup in the patients with bone chips alone but remained unchanged in the artificial cage group. The functional outcome correlated with radiographic fusion status. We conclude artificial cages provide better functional outcomes and radiographic improvement than bone chips alone in posterior lumbar interbody fusion for lumbar spondylolisthesis, although both techniques achieved comparable fusion rates. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.