Biomechanical Research of Three Parallel Cannulated Compression Screws in Oblique Triangle Configuration for Fixation of Femoral Neck Unstable Fractures.

OBJECTIVE: Surgical treatment with internal fixation, specifically percutaneous fixation with three cannulated compression screws (CCSs), is the preferred choice for young and middle-aged patients. The mechanical advantage of the optimal spatial configuration with three screws provides maximum dispersion and cortical support. We suspect that the spatial proportion of the oblique triangle configuration (OTC) in the cross-section of the femoral neck isthmus (FNI) may significantly improve shear and fatigue resistance of the fixed structure, thereby stabilizing the internal fixation system in femoral neck fracture (FNF). This study aims to explore the mechanical features of OTC and provide a mechanical basis for its clinical application. METHODS: Twenty Sawbone femurs were prepared as Pauwels type III FNF models and divided equally into two fixation groups: OTC and inverted equilateral triangle configuration (IETC). Three 7.3 mm diameter cannulated compression screws (CCSs) were used for fixation. The specimens of FNF after screw internal fixation were subjected to static loading and cyclic loading tests, respectively, with five specimens for each test. Axial stiffness, 5 mm failure load, ultimate load, shear displacement, and frontal rotational angle of two fragments were evaluated. In the cyclic loading test, the load sizes were 700 N, 1400 N, and 2100 N, respectively, and the fracture end displacement was recorded. Results were presented as means ± SD. Data with normal distributions were compared by the Student's t test. RESULTS: In the static loading test, the axial stiffness, ultimate load, shear displacement, and frontal rotational angle of two fragments were (738.64 vs. 620.74) N/mm, (2957.61 vs. 2643.06) N, (4.67 vs. 5.39) mm, and (4.01 vs. 5.52)° (p < 0.05), respectively. Comparison between the femoral head displacement after 10,000 cycles of 700N cyclic loading and total displacement after 20,000 cycles of 700-1400N cyclic loading showed the OTC group was less than the IETC group (p < 0.05). A comparison of femoral head displacement after 10,000 cycles of 1400N and 2100N cycles and total displacement after 30,000 cycles of 700-2100N cycles showed the OTC group was less than another group, but the difference was not significant (p > 0.05). CONCLUSION: When three CCSs are inserted in parallel to fix FNF, the OTC of three screws has obvious biomechanical advantages, especially in shear resistance and early postoperative weight-bearing, which provides a mechanical basis for clinical selection of ideal spatial configuration for unstable FNF.

The Oval-like Cross-section of Femoral Neck Isthmus in Three-dimensional Morphological Analysis.

OBJECTIVES: To investigate the cross-section shape of the femoral neck isthmus (FNI) in three-dimensional reconstruction model of the femoral neck. METHODS: From December 2009 to December 2012, computed tomography (CT) data of bilateral hip joint from 200 consecutive patients (137 males and 63 females, 69.41 ± 9.21 years old, ranged from 50-85 years old) who underwent surgical treatments for proximal femoral fracture were retrospectively reviewed. The 3D model of the proximal femur was reconstructed, and the "inertia axis" method, which was applied to measure the long and short axes of the cross-section of the FNI, was established. The cross-sectional area and perimeter were calculated by a formula using the length of the long and short axes and then compared with the actual measured values by the software. Correlation between the descriptive parameters of the FNI cross-section (area, perimeter, and eccentricity) and patients' demographics (age, height, and weight) was analyzed. Stepwise linear regression analysis was used to determine the main relevant factors. RESULTS: The ICC results showed excellent data reproducibility ranged from 0.989 to 0.996. There was no significant difference in the cross-sectional area of the FNI between the actual measured values and the predicted values using the formula (732.83 ± 126.74 mm2 vs 731.62 ± 128.15 mm2 , P = 0.322). The perimeter using the two methods showed narrow while significant difference (97.86 ± 8.60 mm vs 92.84 ± 8.65 mm, P < 0.001), the actual measured values were about 5 mm greater than the predicted values. The parameters (area, perimeter, and eccentricity) were significantly larger in male than female (P < 0.001). A positive correlation between the cross-sectional area, perimeter, height, and weight was observed. The stepwise linear regression analysis showed that the regression equation of the FNI area was as follows: Y = -1083.75 + 1033.86 × HEIGHT + 1.92 × WEIGHT, R2 = 0.489. CONCLUSION: The cross-section shape of the FNI appears to be oval-like in the 3D model, which is separated according to the inertia axis, and the findings proposed an anatomical basis for the further study of the spatial configuration of cannulated screws in the treatment of femoral neck fractures.

Comparison of perioperative outcomes of robotic-assisted versus video-assisted thoracoscopic right upper lobectomy in non-small cell lung cancer.

BACKGROUND: Robotic-assisted thoracic surgery (RATS) has been widely used in the treatment of lung cancer. The perioperative outcomes of right upper lobectomy (RUL) using RATS and video-assisted thoracic surgery (VATS) were retrospectively investigated and compared. We aimed to summarize a single-center experience of RATS and 4-port unidirectional VATS in RUL, and to discuss the safety and the essentials of the surgery. METHODS: We retrospectively analyzed the 685 with non-small cell lung cancer (NSCLC) patients who underwent minimally invasive RUL in our center by the same surgical group from January 2015 to December 2019. Both RATS and VATS were performed with three ports with utility incision. The 685 participants were divided into RATS (335 cases) and VATS (350 cases) groups according to surgical method. Baseline characteristics and perioperative outcomes including dissected lymph nodes, postoperative duration of drainage, postoperative hospital stay, and incidence of postoperative complications were compared between the groups. RESULTS: In the 685 patients enrolled, the baseline characteristics were comparable, and no postoperative 30-day mortality or intraoperative blood transfusion were observed. Compared with VATS, RATS had less surgical duration (90.22±12.16 vs. 92.68±12.26 min, P<0.001), less length of stay (4.71±1.37 vs. 5.26±1.56 days, P<0.001), and decreased postoperative duration of drainage (3.49±1.15 vs. 4.09±1.57 days, P<0.001). No significant difference was observed in the lymph nodes dissection, blood loss, conversion rate and morbidities. The cost of RATS was much higher than VATS (85,329.41±12,893.44 vs. 68,733.43±14,781.32 CNY, P<0.001). CONCLUSIONS: Robot assisted RUL had similar perioperative outcomes compared to VATS RUL lobectomy using similar three port with utility incision technique. The advantages of RATS included finer dissection of lymph node, relatively less operation time, earlier chest tube removal and discharge.

Three-dimensional morphological analysis of the femoral neck torsion angle-an anatomical study.

BACKGROUND: The femoral neck torsion angle (FNTA) is an important but often neglected parameter in assessments of the anatomical morphology of the femoral neck, which is often confused with the femoral neck anteversion angle (FNAA) in the current literature. Currently, the measurement methods reported in the literature all adopt the naked eye or two-dimensional (2D) visualization method, and the measurement parameters and details are not clearly defined. The objection of this research was to provide a reliable 3D method for determining the femoral neck axis, to improve the measurement method of the FNTA, and to analyze the anatomical and clinical significance of the results. METHODS: Computed tomography (CT) data of 200 patients who received a lower extremity CT angiography examination were selected, and the bilateral femurs were reconstructed with three dimensional CT (3D CT). First, the 3D axis of the femoral neck was built. Second, the long axis of the cross section the femoral neck isthmus (FNI) and femoral neck basilar part (FNB) were confirmed by the "inertia axes" method, and the plane consisting of the long axis of the cross-section and the center of the femoral head was defined as the long axial plane. Third, the coronal plane of the proximal femur was determined through the long axis of the proximal femur and the femoral coronal. Finally, the FNTAs (the angles between the long axial planes and the coronal plane of the proximal femur) of FNI and FNB were measured. The size of FNTA was compared between the sexes and sides and different locations, the correlation between the parameters and age, height, and weight were evaluated. RESULTS: The difference in FNTA was statistically significant between the isthmus and the basilar part (isthmus 30.58 ± 8.90° vs. basilar part 23.79 ± 3.98°; p < 0.01). Significant difference in the FNTA was observed between the sexes (males 31.99 ± 9.25° vs. females 27.49 ± 7.19°; p < 0.01). The increase in FNTA from the basilar part to the isthmus was 6.79 ± 8.06°, and the male (7.87 ± 8.57°) was greater than the female (4.44 ± 6.23°, p < 0.01). However, no significant difference in the values was observed between sides. Height exerted the greatest effect on the FNTA according to the correlation analysis (r = 0.255, p< 0.001). CONCLUSIONS: This study found a reliable 3D method for the determination of the femoral neck axis improved the measurement method of the FTNTA and made it more accurate and repeatable. The results provided a methodological basis and theoretical support for the research and development of internal fixation device for femoral neck fracture and the spatial configuration of implants in treatment. And the optimal opening point of the femoral medullary cavity was recommended to locate at the posterior position of the top of the femoral neck cross-section during hip replacement.

Finite element analysis of an intramedulary anatomical strut for proximal humeral fractures with disrupted medial column instability: A cohort study.

BACKGROUND: Lateral locking plate (LLP) fixation has gained popularity for the treatment of proximal humeral fractures (PHFs); however, complications can occur due to loss of the medial cortical buttress from fracture comminution. MATERIALS AND METHODS: We designed a novel intramedullary anatomical medial strut with allograft bone (IAMSAB) using MIMICS software to specifically fill the intramedullary canal of the proximal humeral bone. We used finite element analysis to evaluate the biomechanical characteristics of a LLP, LLP-intramedullary fixation system (IFS), LLP-anatomical medial locking plate (AMLP), or the combined application of a LLP and IAMSAB (LLP-IAMSAB) fixation construct in patients with a PHF and an unstable medial column. RESULTS: For axial or rotational loads, under (normal) Nor or osteoporotic (Ost) bone conditions, the LLP-IAMSAB fixation construct was significantly stiffer than the LLP-IFS fixation construct, and displacement at the fracture site after LLP-IAMSAB fixation was significantly less than after LLP or LLP-IFS fixation (P < 0.05). Stiffness of the LLP-IAMSAB and LLP-AMLP fixation constructs and displacement at the fracture site after LLP-IAMSAB and LLP-AMLP fixation were not significantly different. The IFS, AMLP, and IAMSAB shared the load in the LLP and decreased the risk of implant failure. There were no significant differences in von Mises stress and stress distribution after fixation with the LLP-IFS, LLP-AMLP, and LLP-IAMSAB constructs. CONCLUSION: These data suggest that the IAMSAB can provide direct medial support or resistance to rotation and augment the biomechanics of the LLP. The combined application of the IAMSAB and LLP may achieve functional outcomes that are similar to the LLP-AMLP fixation construct.

Perioperative outcomes of radical lobectomies using robotic-assisted thoracoscopic technique vs. video-assisted thoracoscopic technique: retrospective study of 1,075 consecutive p-stage I non-small cell lung cancer cases.

BACKGROUND: Robotic thoracoscopic surgery was first done in mainland China in 2009 and has gained popularity in the past few years. Here, we present the largest Chinese series of robotic lobectomy for early-stage non-small cell lung cancer (NSCLC) to date. We aimed to compare the perioperative outcomes of our three-arm robotic-assisted lobectomy (RAL3) and video-assisted lobectomy (VAL) for p-stage I NSCLC and report the approach of the robotic anatomic lobar resections of our center. METHODS: We retrospectively collected and analyzed the data of 1075 stage I NSCLC patients who underwent minimally invasive lobectomies (237 RAL3 cases and 838 VAL cases) by the same surgical team from May 2013 to April 2016. Propensity score matching (PSM) was used to minimize the bias between the two groups. Perioperative outcomes were analyzed. RESULTS: Compared to the VALs, the RAL3s had more retrieved lymph nodes (LNs) (9.70 vs. 8.45, P=0.000), less POD1 drain (230.91 vs. 279.79 mL, P=0.001), shorter chest tube duration (3.84 vs. 4.33 d, P=0.003) and shorter postoperative length of stay (4.97 vs. 5.45 d, P=0.004), but a higher cost (¥93,244.84 vs. ¥67,055.82, P=0.000). No significant difference was observed between the RAL3 and VAL groups concerning the average skin-to-skin time (90.84 vs. 92.25 min, P=0.624), conversion rate (1.3% vs. 0.87%, P=1.000) and prolonged postoperative hospital stay (PPHS) rate (3.0% vs. 4.3%, P=0.694). CONCLUSIONS: This study confirms that RAL3 is a safer and more effective technique than VAL for the treatment of early-stage NSCLC.

Robotic-assisted right medial and anterior basal segmentectomy (S7+S8).

Anatomical segmentectomy for medial (S7) and anterior basal segments (S8) is still challenging even with substantial progress in surgical technique over these years. We believe that segmentectomy could be much more comfortable with the application of the da Vinci surgical system in thoracic surgery. With nearly 10-year experience of robotic thoracic surgery, we gradually develop a new way of port placement and surgery. Here we present a step-by-step right medial and anterior basal segmentectomy (S7+S8) with a high-quality video and preference cards.

Effects of melanocortin-4 receptor agonists and antagonists on expression of genes related to reproduction in spotted scat, Scatophagus argus.

Melanocortin-4 receptor (Mc4r) function related to reproduction in fish has not been extensively investigated. Here, we report on gene expression changes by real-time PCR following treatment with Mc4r agonists and antagonists in the spotted scat (Scatophagus argus). Using in vitro incubated hypothalamus, the Mc4r nonselective agonist NDP-MSH ([Nle4, D-Phe7]-α-melanocyte stimulating hormone; 10-6 M) and selective agonist THIQ (N-[(3R)-1, 2, 3, 4-Tetrahydroisoquinolinium-3-ylcarbonyl]- (1R)-1-(4-chlorobenzyl)-2-[4-cyclohexyl-4-(1H-1,2,4-triazol-1-ylmethyl) piperidin-1-yl]-2-oxoethylamine; 10-7 M) significantly increased the expression of gnrh (Gonadotropin releasing hormone), while the Mc4r nonselective antagonist SHU9119 (Ac-Nle-[Asp-His-DPhe/DNal(2')-Arg-Trp-Lys]-NH2; 10-6 M) and selective antagonist Ipsen 5i (compound 5i synthesized in Ipsen Research Laboratories; 10-6 M) significantly inhibited gnrh expression after 3 h of incubation. In incubated pituitary tissue, NDP-MSH and THIQ significantly increased the expression of fshb (Follicle-stimulating hormone beta subunit) and lhb (Luteinizing hormone beta subunit), while SHU9119 and Ipsen 5i significantly decreased fshb and lhb expression after 3 h of incubation. During the in vivo experiment, THIQ (1 mg/kg bw) significantly increased gnrh expression in hypothalamic tissue, as well as the fshb and lhb expression in pituitary tissue 12 h after abdominal injection. Furthermore, Ipsen 5i (1 mg/kg bw) significantly inhibited gnrh expression in hypothalamic tissue, as well as fshb and lhb gene expression in pituitary tissue 12 h after abdominal injection. In summary, Mc4r singling appears to stimulate gnrh expression in the hypothalamus, thereby modulating the synthesis of Fsh and Lh in the pituitary. In addition, Mc4r also appears to directly regulate fshb and lhb levels in the pituitary in spotted scat. Our study suggests that Mc4r, through the hypothalamus and pituitary, participates in reproductive regulation in fish.

New classification of lunate fossa fractures of the distal radius.

BACKGROUND: A die-punch fracture is a depression fracture of the lunate fossa of the distal radius. We propose a morphological classification of die-punch fractures that includes five types: center depression fractures, vertical depression fractures, volar depression fractures, dorsal depression fractures, and double die-punch fractures. METHODS: The radiographs of 112 die-punch fractures treated between January 2005 and January 2015 were retrospectively reviewed. The clinical images were examined independently for two rounds by six orthopedists with different clinical experiences: two residents, two attending physicians, and two consultants. A category-specific kappa score and a kappa score for more than two observers were analyzed. We used Cohen's kappa to test intraobserver variation. RESULTS: The kappa score for interobserver reliability was 0.69 for the first round and 0.70 for the second round. The intraclass correlations were 0.65 and 0.63, respectively. Intraobserver reproducibility using Cohen's kappa test was satisfactory. All of the results indicated a kappa value >0.4, suggesting good agreement within, as well as between, observers. CONCLUSIONS: The outcome was assessed using kappa statistics, which showed good interobserver reliability and intraobserver reproducibility.

PPARγ suppression inhibits adipogenesis but does not promote osteogenesis of human mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are the common progenitors of osteoblasts and adipocytes. A reciprocal relationship exists between osteogenesis and adipogenesis in the bone marrow, and the identification of signaling pathways that stimulate MSC osteogenesis at the expense of adipogenesis is of great importance from the viewpoint of developing new therapeutic treatments for bone loss. The adipogenic transcription factor peroxisome proliferator-activated receptor γ (PPARγ) has been reported to play a vital role in modulating mesenchymal lineage allocation within the bone marrow compartment, stimulating adipocyte development at the expense of osteoblast differentiation. Hence, PPARγ may be a valuable target for drugs intended to enhance bone mass. However, little direct evidence is available for the role played by PPARγ in human mesenchymal lineage allocation. In this study, using human MSCs as an in vitro model, we showed that the two isoforms of PPARγ, PPARγ1 and PPARγ2, were differentially induced during hMSC adipogenesis, whereas only PPARγ1 was detected during osteogenesis. BADGE and GW9662, two potential antagonists of PPARγ, as well as lentivirus-mediated knockdown of PPARγ, inhibited hMSC adipogenesis but did not significantly affect osteogenesis. PPARγ knockdown did not significantly influence the expression level of the osteogenic transcription factor Runx2. Together, these results suggest that PPARγ is not the master factor regulating mesenchymal lineage determination in human bone marrow.

Improved nude mouse models for green fluorescence human endometriosis.

AIM: To establish an improved noninvasive fluorescent animal model for endometriosis. MATERIAL AND METHODS: Adenovirus encoding enhanced green fluorescent protein (Ad-eGFP) was used to transfect primary culture endometrial glandular cells and stromal cells (purified cell transfection and mixed injection, Group 1) as well as endometrial fragments (tissues transfection and injection, Group 2). Transfection results were compared between the cells and tissues in vitro. The GFP-transfected cells suspension of Group 1 or endometrial fragments of Group 2, with similar weight, were injected into nude mice subcutaneously and noninvasively observed every 5 days until day 15 (Subgroup 1, N = 5), day 20 (Subgroup 2, N = 5) or day 25 (Subgroup 3, N =11). The positive rates and duration times of the fluorescent lesions were calculated. RESULTS: After 18 h of incubation, glandular cells and stromal cells all had higher GFP-positive rates. In vivo imaging showed that the GFP positive rates of Group 1 were significantly higher than those of Group 2. The fluorescent-positive durations of Groups 1 and 2 were 23.636 ± 4.523 days and 5.909 ± 5.394 days, respectively (P < 0.001). In vivo analysis demonstrated that on days 15, 20, and 25, there were more typical lesions and fluorescent-positive lesions formed in Group 1 and that the lesion weight in Group 1 was greater. The structures of the lesions were all identified as human origin. CONCLUSION: A noninvasive animal model for endometriosis created by subcutaneous injection of an Ad-eGFP-transfected endometrial glandular and stromal cells suspension had higher a positive rate, longer duration time of fluorescent imaging and greater lesion weight.