Augmented reality hologram combined with pre-bent distractor enhanced the accuracy of distraction vector transfer in maxillary distraction osteogenesis, a study based on 3D printed phantoms.

Background: Vector control is a significant concern in maxillary distraction osteogenesis (DO). Distraction vector planning on the patient's 3D-printed skull phantom is more intuitive for surgeons and cost-efficient than virtual surgical planning. However, the accuracy of transferring the planned vector to intraoperative (vector transfer) according to the shape of the pre-bent footplate alone is relatively limited. The application of augmented reality (AR) in surgical navigation has been studied for years. However, few studies have focused on its role in maxillary DO vector transfer. This study aimed to evaluate the accuracy of AR surgical navigation combined with the pre-bent distractor in vector transfer by comparing it with the pre-bent distractor alone. Methods: Ten patients with maxillary hypoplasia were enrolled with consent, and three identical 3D-printed skull phantoms were manufactured based on per patient's corresponding pre-operative CT data. Among these, one phantom was for pre-operative planning (n = 10), while and the other two were for the AR+Pre-bending group (n = 10) and the Pre-bending group (n = 10) for the experimental surgery, respectively. In the Pre-bending group, the distraction vector was solely determined by matching the shape of footplates and maxillary surface. In the AR+Pre-bending group, the distractors were first confirmed to have no deformation. Then AR surgical navigation was applied to check and adjust the vector in addition to the steps as in the Pre-bending Group. Results: For the angular deviation of the distraction vector, the AR+Pre-bending group was significantly smaller than the Pre-bending group in spatial (p < 0.001), x-y plane (p = 0.002), and y-z plane (p < 0.001), and there were no significant differences in the x-z plane (p = 0.221). The AR+Pre-bending group was more accurate in deviations of the Euclidean distance (p = 0.004) and the y-axis (p = 0.011). In addition, the AR+Pre-bending group was more accurate for the distraction result. Conclusions: In this study based on 3D printed skull phantoms, the AR surgical navigation combined with the pre-bent distractor enhanced the accuracy of vector transfer in maxillary DO, compared with the pre-bending technique alone.

Clinical application of the mixed reality technique to assist the location and anatomy of perforator vessels of the anterolateral femoral flap / 口腔疾病防治

Objective@#To explore the clinical application value of mixed reality technology in locating perforator vessels and assisting perforator vessel dissection to harvest anterolateral thigh flaps.@*Methods@#Six patients who needed anterolateral thigh flap repair after resection of oral and maxillofacial tumors were recruited from the Department of Oral and Maxillofacial Surgery of Nanchong Central Hospital from January 2020 to January 2021. Before surgery, the CT angiography data of the lower limbs of the patients carrying the calibration points were imported into the data workstation to perform 3D reconstruction of the perforator vessels and surrounding tissues of the thigh, and the reconstruction results were imported into Microsoft HoloLens 2 glasses. During the operation, calibration was performed at the calibration point of the operative area so that the preoperative reconstruction results were superimposed on the operative area through Microsoft HoloLens 2 glasses. The clinical application value of mixed reality technology assisted perforator vessel location and anatomy of anterolateral femoral perforator flap was discussed from six aspects: whether the perforator vessel was reconstructed preoperatively, intraoperative calibration time, whether the actual position of the perforating vessels passing through the fascia lata fulcrum deviated from the preoperative reconstruction result within 1 cm, time required to harvest the flap, and whether the actual route of the perforator vessel was consistent with the reconstruction result, and whether the postoperative flap survived.@*Results @# The position and course of perforating vessels were successfully reconstructed in 6 cases before the operation. The actual course of perforating vessels during the operation was consistent with the reconstruction results. The deviation between the actual position of the perforating points and the preoperative reconstruction results was within 1 cm, which met the requirements of the actual asisting of the anterolateral thigh flap. The average time of flap harvest was (70.50 ± 7.20) min. The average calibration time was (13.33 ± 5.50) min. All flaps survived.@* Conclusions @# Mixed reality technology projects the reconstruction results of anterolateral femoral perforator vessels directly into the operative area, which provides a new method for asisting localization and anatomy of anterolateral femoral flap perforator vessels and reduces the possibility of injury to perforator vessels.

Simulation-based training following a theoretical lecture enhances the performance of medical students in the interpretation and short-term retention of 20 cross-sectional transesophageal echocardiographic views: a prospective, randomized, controlled trial.

BACKGROUND: Both simulation-based training and video-based training serve as educational adjuncts for learning TEE among medical students. In the present study, we hypothesized that simulation-based training would better enhance the performance of medical students in the interpretation of 20 cross-sectional views compared to video-based training. METHODS: A total of 120 4th-year undergraduate medical students were enrolled in the present study. The study began with a pre-test of all the participants, followed by a 90-min theoretical lecture and a post-test. Subsequently, the participants were randomly divided into the video-based group (Group V) and simulation-based group (Group S). Next, Group V received 60 min of TEE video learning, while Group S received 60 min of TEE simulator training. After the respective training, both the groups undertook the retention-test 1 and retention-test 2, 1 week and 1 month later, respectively. The performance for each test was evaluated by five views, which were selected randomly and, respectively, from a set of 20 cross-sectional views. The primary outcome was the performance of the retention-test 1. Secondary outcomes included: (1) comparison the performances of the pre-test, post-test, and retention-test 2 between two groups; (2) comparison the performances of pre-test and post-test in the same group; (3) comparison the performances of retention-test 1, and retention-test 2 in the same group. RESULTS: Better performances were observed in Group S in both retention-test 1 (Group V: 63.2 [52.6, 77.6] vs. Group S: 89.5 [68.4, 100.0], P < 0.001) and retention-test 2 (Group V: 58.0 [48.0, 72.0] vs. Group S: 74.0 [64.0, 80.0], P < 0.001) compared to Group V. No statistically significant differences were observed in the performances of pre-test (Group V: 8.3 [4.2, 12.5] vs. Group S: 8.3 [4.2, 12.5], P = 0.825) or post-test (Group V: 46.2 [38.5, 57.7] vs. Group S: 44.2 [38.5, 56.7], P = 0.694) between the two groups. The improvement had been observed in the post-test, compared with pre-test in the same group, respectively (Group V in post-test: 46.2 [38.5, 57.7] vs. Group V in pre-test: 8.3 [4.2, 12.5], P < 0.001; Group S in post-test: 44.2 [38.5, 56.7] vs. Group S in pre-test: 8.3 [4.2, 12.5], P < 0.001). However, the performance in retention-test 2 was significantly reduced, compared with retention-test 1 in the same group, respectively (Group V in retention-test 2: 58.0 [48.0, 72.0] vs. Group V in retention-test 1: 63.2 [52.6, 77.6] P = 0.005; Group S in retention-test 2: 74.0 [64.0, 80.0] vs. Group S in retention-test 1: 89.5 [68.4, 100.0], P < 0.001). CONCLUSIONS: Following a 90-min theoretical lecture, simulation-based training better enhanced the performance of medical students in the interpretation and short-term retention of 20 cross-sectional views compared to video-based training. TRIAL REGISTRATION: http://www.chictr.org.cn ( ChiCTR2000033519 , 3/June/2020).

Analgesic efficacy of postoperative bilateral, ultrasound-guided, posterior transversus abdominis plane block for laparoscopic colorectal cancer surgery: a randomized, prospective, controlled study.

BACKGROUND: We assessed whether a postoperative bilateral, ultrasound-guided, posterior transversus abdominis plane (TAP) block could reduce 24 h rescue tramadol requirement compared with placebo in patients undergoing elective laparoscopic colorectal cancer surgery. METHODS: Patients scheduled to undergo elective laparoscopic surgery following the diagnosis of colorectal cancer were included in this study and randomized into Group and Group Control. The patients received a postoperative bilateral, ultrasound-guided, posterior TAP block in either 20 mL of 0.5% ropivacaine (Group TAP) per side or an equivalent volume of normal saline (Group Control). The primary outcome was the cumulative consumption of rescue tramadol within 24 h after the surgery. Secondary endpoints included (1) resting and movement numerical rating scale (NRS) pain scores at 2, 4, 6, 12, 24, 48, and 72 h; (2) incidences of related side effects; (3) time to the first request for rescue tramadol; (4) patient satisfaction regarding postoperative analgesia; (5) time to restoration of intestinal function; (6) time to mobilization; and (7) the length of hospital stay. RESULTS: In total, 92 patients were randomized, and 82 patients completed the analysis. The total rescue tramadol requirement (median [interquartile range]) within the first 24 h was lower in Group TAP (0 [0, 87.5] mg) than in Group Control (100 [100, 200] mg), P < 0.001. The posterior TAP block reduced resting and movement NRS pain scores at 2, 4, 6, 12, and 24 h after surgery (all P < 0.001) but showed similar scores at 48 h or 72 h. A higher level of satisfaction with postoperative analgesia was observed in Group TAP on day 1 (P = 0.002), which was similar on days 2 (P = 0.702) and 3 (P = 0.551), compared with the Group Control. A few incidences of opioid-related side effects (P < 0.001) and a lower percentage of patients requiring rescue tramadol analgesia within 24 h (P < 0.001) were observed in Group TAP. The time to the first request for rescue analgesia was prolonged, and the time to mobilization and flatus was reduced with a shorter hospital stay in Group TAP as compared with Group Control. CONCLUSIONS: A postoperative bilateral, ultrasound-guided, posterior TAP block resulted in better pain management and a faster recovery in patients undergoing laparoscopic colorectal cancer surgery, without adverse effects. TRIAL REGISTRATION: The study was registered at http://www.chictr.org.cn ( ChiCTR-IPR-17012650 ; Sep 12, 2017).

[Application of high frequency color Doppler ultrasonography combined with microvascular stapler in maxillofacial defect repair].

Objective:To evaluate the clinical application value of high frequency color Doppler ultrasound（HFCUS） combined with microvascular stapler in the repair of oral and maxillofacial defects with the anterolateral thigh perforator flap. Method:Forty maxillofacial malignant tumor patients were divided into HFCUS+stapler group（23 cases） and control group（17 cases）. All of cases used anterolateral thigh flap without fascia lata to repair the soft tissue defect in the operative area. One artery and two veins were anastomosed during the operation. The flaps were harvested from 6.0 cm×7.0 cm to 10.0 cm×12.0 cm, and the donor sites were closed and sutured at the same time. In group HFCUS+stapler, HFCUS was used to locate the perforating vessels and mark the location on the body surface the operation, and the vein was anastomosed intraoperatively with a stapler. In the control group, only iliac patella line was fixed before operation, and the vein was manually sutured during operation. The clinical data of 2 groups was evaluated by comparing the time consumption of flap harvest, the vascular anastomosis, the incidence of postoperative venous crisis, and the long-term survival rate of flap. Result:In the HFCUS+stapler group, a total of 27 perforators were found before the operation, 24 perforators within 1.0 cm from the preoperative marker were actually detected during the operation, and the remaining 3 perforators were about 1.7 cm, 2.0 cm and 2.5 cm from the marker respectively, with an accuracy rate of 88.9%. HFCUS+stapler group used （63.17±7.80） min to harvest the flap, while the control group used （85.47±7.41） min HFCUS+stapler group took significantly less time than the control group（P<0.001）. The arterial anastomat time in the HFCUS+stapler group was （9.48±1.20） min and it was （9.18±1.13） min in the control group. The difference between the two groups was not statistically significant（P=0.426）. The total anastomosis time of the two veins was （14.87±2.62） min in the HFCUS+stapler group and （33.06±3.86） min in the control group. The HFCUS+stapler group had significantly less anastomosing time than the control group（P<0.001）. In HFCUS+stapler group, no arteriovenous crisis occurred after operation, and all flaps survived well 15 days after operation. In the control group, 2 cases had venous crisis after operation（P=0.091）. Conclusion:HFCUS combined with iliac patellar line can improve the accuracy of anatomical perforated vessels, reduce the time of flap harvesting, and reduce the possibility of accidental injury of perforated vessels. The use of microvascular stapler for vein anastomosis can reduce the operation time and improve the survival rate of flap. The combination of the two can significantly reduce the operation time of microsurgical repairing maxillofacial soft tissue defect, improve the operation quality, and has higher clinical application value.

DNA Demethylation Rescues the Impaired Osteogenic Differentiation Ability of Human Periodontal Ligament Stem Cells in High Glucose.

Diabetes mellitus, characterized by abnormally high blood glucose levels, gives rise to impaired bone remodeling. In response to high glucose (HG), the attenuated osteogenic differentiation capacity of human periodontal ligament stem cells (hPDLSCs) is associated with the loss of alveolar bone. Recently, DNA methylation was reported to affect osteogenic differentiation of stem cells in pathological states. However, the intrinsic mechanism linking DNA methylation to osteogenic differentiation ability in the presence of HG is still unclear. In this study, we found that diabetic rats with increased DNA methylation levels in periodontal ligaments exhibited reduced bone mass and density. In vitro application of 5-aza-2'-deoxycytidine (5-aza-dC), a DNA methyltransferase inhibitor, to decrease DNA methylation levels in hPDLSCs, rescued the osteogenic differentiation capacity of hPDLSCs under HG conditions. Moreover, we demonstrated that the canonical Wnt signaling pathway was activated during this process and, under HG circumstances, the 5-aza-dC-rescued osteogenic differentiation capacity was blocked by Dickkopf-1, an effective antagonist of the canonical Wnt signaling pathway. Taken together, these results demonstrate for the first time that suppression of DNA methylation is able to facilitate the osteogenic differentiation capacity of hPDLSCs exposed to HG, through activation of the canonical Wnt signaling pathway.

PPARγ and Wnt Signaling in Adipogenic and Osteogenic Differentiation of Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) arise from a variety of tissues, including bone marrow and adipose tissue and, accordingly, have the potential to differentiate into multiple cell types, including osteoblasts and adipocytes. Research on MSCs to date has demonstrated that a large number of transcription factors and ectocytic or intrastitial signaling pathways regulate adipogenic and osteogenic differentiation. A theoretical inverse relationship exists in adipogenic and osteogenic lineage commitment and differentiation, such that signaling pathways induce adipogenesis at the expense of osteogenesis and vice versa. For example, peroxisome proliferator-activated receptor γ(PPARγ), which belongs to the nuclear hormone receptor superfamily of ligand-activated transcription factors, is known to function as a master transcriptional regulator of adipocyte differentiation, and inhibit osteoblast differentiation. Moreover, recent studies have demonstrated that inducers of osteogenic differentiation, such as bone morphogenetic protein (BMP) and Wnt, inhibit the function of PPARγ transactivation during MSC differentiation towards adipocytes through a variety of mechanisms. To illustrate this, the canonical Wnt/ß-catenin pathway represses expression of PPARγ mRNA, whereas the noncanonical Wnt pathway activates histone methyltransferases that inhibit PPARγ transactivation via histone H3 lysine 9 (H3K9) methylation of its target genes. The role of microRNAs (miRNAs) in adipogenesis and osteoblastogenesis is garnering increased attention, and studies in this area have shed light on the integration of miRNAs with Wnt signaling and transcription factors such as Runx2 and PPARγ. This review summarizes our current understanding of the mechanistic basis of these signaling pathways, and indicates future clinical applications for stem cell-based cell transplantation and regenerative therapy.