[Application value of CTA combined with digital technology in the design of anterolateral thigh flap in repairing operative defect of head, neck and maxillofacial tumor resection]

Objective:To explore the value of computed tomography angiography （CTA） combined with digital technology in the vascular anatomy of the anterior thigh flap in patients with operative defects after head, neck and maxillofacial tumor operation, and in the design of preoperative and intraoperative flaps. Methods:Twenty-five cases of patients with postoperative defect after head, neck and maxillofacial tumor surgery admitted to our hospital from April 2018 to April 2019 were selected. Preoperative CTA and digital technology were used to clarify vascular anatomy and other related conditions, and the operation was carried out. Consistency analysis was applied to evaluate the value of CTA, digital technology and CTA combined digital technology in the localization of anterolateral thigh perforator flap with operative defects after head, neck and maxillofacial tumor resection, and the diagnostic efficacy of the three methods was compared. Results:The preoperative CTA examination revealed that there were 26 intermuscular perforators with a diameter greater than 0.8 mm in the flap donor site, and 17 musculocutaneous perforators with a diameter greater than 1.0 mm. During the operation, it was actually found that there were 27 intermuscular perforators with a diameter greater than 0.8 mm and 17 musculocutaneous perforators with a diameter greater than 1.0 mm. The accuracy rates of Pre-operative examination were 96.29% and 100.00%, respectively.In addition, the lateral femoral circumflex artery determined by digital technology. The starting position of the descending branch, the diameter of the vessel, the direction of the perforating vessel, and the maximum length of the pedicle that can be cut were consistent with the actual observation during the operation. All the patients in the group successfully underwent flap removal and repair. After the operation, 2 skin flaps suffered from vascular crisis, and survived under the managements of anticoagulation, lifting of restraint, and massage. The rest of the flaps survived smoothly. The patients were followed up for 3-12 months postoperatively. Twenty-four cases of skin flaps had good appearance. One case had swollen wound And the appearance of the skin flap was satisfactory after elective secondary thinning. Among the 25 patients with head and neck defects, in the perforator location examination, 18 cases were detected by CTA, with a sensitivity of 90.0%, a specificity of 60.0%, an accuracy of 84.0%, and Kappa=0.500. 19 cases was detected by digital technology, with a sensitivity of 86.36%, a specificity of 66.67%, a accuracy rate of 84.00%, and Kappa=0.412. 21 cases was detected by CTA combined with digital technology,with a sensitivity of 95.45%, a specificity of 66.67%, a accuracy of 92.00%, and Kappa=0.621. The accuracy of CTA combined with digital technology in the perforator positioning of patients with head and neck tumor defects was significantly higher than that of the single method（P<0.05）. Conclusion:CTA has good application value in the positioning of perforator in patients with head, neck and maxillofacial tumor defects. In addition, the combination of CTA and digital technology can improve the accuracy of the vascular anatomy of the anterior thighflap and the design of the preoperative and intraoperative flaps, which is beneficial to surgery clinical implementation.

[Establishment of a mouse model bearing orthotopic temozolomide-resistant glioma]

OBJECTIVE

To establish a mouse model bearing orthotopic temozolomide (TMZ)-resistant glioma that mimics the development of drug resistance in gliomas in vivo.

METHODS

Seventy-eight adult C57BL/6 mice were randomly divided into 6 groups (n=13), including 3 TMZ induced groups with low, medium and high doses (5, 25, and 50 mg/kg, respectively) and 3 control groups. In each group, 5 mice were used for evaluating tumor size, 5 for observing survival, and 3 for collecting tumor tissues for primary cell culture. In low-dose TMZ induced group, 3 mice bearing orthotopic murine glioma GL261 cell xenografts received intraperitoneal injections of 5 mg/kg TMZ for 5 days followed by a 10-day washout period before collecting glioma tissues. Tumor cell suspensions were prepared and injected in the mice in the medium-dose group, which were treated with the same protocol but with an increased TMZ dose, and the tumor cells harvested from 3 mice were injected in the high-dose group. The mice bearing GL261 cell xenografts in the 3 control groups received no treatment or were injected with medium- or high-dose TMZ. Cell colony forming assay was used to assess TMZ resistance of each generation of the tumor cells; CCK8 assay was used to determine drug resistance index of the cells.

RESULTS

The mouse models bearing TMZresistant glioma was successfully established. The cells from the high-dose induced group showed a significantly higher colony-forming rate than those from the high-dose control group (P < 0.05), and had a drug resistance 4.25 times higher than that of the cells from untreated control group. High-dose TMZ significantly reduced the tumor volume in the control group (P < 0.05) but not in the high-dose induced group (P < 0.01). The survival time of the tumor-bearing mice was significantly shortened in the high-dose induced group (P=0.0018).

CONCLUSIONS

Progressive increase of TMZ doses in mice bearing orthotopic gliomas can effectively induce TMZ resistance of the gliomas.