Clinical Application of an Original Vascular Anastomosis: A Clinical Multicenter Study

Mathematical Modeling of Vessel Geometry and Circumference in Microvascular Surgery

Introduction

Microvascular anastomosis has traditionally been executed with a perpendicular transection through the vessel at the widest diameter to increase circumference and thus increase blood flow while decreasing resistance. In Chen's 2015 article, it was suggested that an "open Y" would improve vessel size match, and Wei and Mardini discuss angled transections of the vessels. This project aims to explore the geometric configurations feasible at the anastomotic transection and mathematically model the resulting hypothetical increases in circumference.

Materials and Methods

The mathematical models were theoretically developed by our team. The formulas model increases in circumference of the transection at different distances in relation to the bifurcation of a blood vessel, as well as changes in circumference at different transection angulations. An in vitro exploration as to the anastomotic feasibility of each geometric cut was completed on ten poultry tissue specimens.

Results

The mathematical models demonstrated the change in vessel circumference, with multiple geometric designs calculated, best shown through diagrams. For example, if the vessel width is 1 mm, the distance from the increasing vessel diameter to the final bifurcation is 1 mm, and the bifurcation angle is 45°, the circumference of the transected vessel increases by 82.8%. Models of transections at different angulations, for instance 30°, 45°, and 60°, yield an increase in elliptical circumference of 8.0%, 22.5%, and 58.1%, respectively. Additional derivations calculate the elliptical circumference at any angle in a single vessel, and at any angle in a bifurcating vessel.

Conclusion

The theoretical and clinical aim of this project is to increase awareness of the anastomotic creativity and mathematically demonstrate the optimal anastomotic geometry, which has not been objectively explored to our knowledge. An in vivo study would further support clinical improvements, with the aim to map postoperative fluid dynamics through the geometric anastomoses.

Lateral skull base surgery for posterior oral cavity cancer

The aim of this study was to better understand posterior oral cavity cancer (POCC) and its surgical treatment. This was a retrospective study of 76 patients who were diagnosed with POCC and underwent surgical treatment. Twenty-eight patients were treated with anatomical unit resection surgery (AURS) and 48 patients with conventional surgery. After initial treatment with curative intent, the patients were followed-up regularly with clinical examinations and imaging; the median duration of follow-up was 30.9 months (range 2-67 months). The 3-year overall survival was 64.3% in the experimental AURS group and 39.6% in the conventional surgery control group (hazard ratio 0.49, 95% confidence interval 0.26-0.93; P=0.031). The 3-year disease-free survival was 64.3% in the experimental group and 37.5% in the control group (hazard ratio 0.53, 95% confidence interval 0.27-1.02; P=0.114). In conclusion, AURS is an effective surgical treatment for POCC that can considerably improve patient survival rates.

Application of a new classification of chimeric anterolateral thigh free flaps

BACKGROUND

The anterolateral thigh free flap is one of the most commonly used flaps in reconstructive procedures. The purpose of this study was to assess this new classification of chimeric anterolateral thigh free flaps.

METHODS

Sixty-five patients underwent free anterolateral thigh chimeric free flap reconstruction of defects in the head and neck region. We summarized the anatomic features of perforators, including the number and origin of the perforators.

RESULTS

Sixty-five cases of femoral anterolateral double island flaps were divided into 3 types: trunk type (type I), 11 cases (16.9%), in which the perforators of two flaps originated in the descending branch and the transverse branch of the lateral femoral circumflex artery; branch type (type II), 45 cases (69.3%), in which both the perforators originated in the descending branch or the transverse branch of the lateral femoral circumflex artery; and bifurcation type (type III), 9 cases (13.8%), in which two perforators originated in the bifurcation of one perforator that originated in the descending branch or the transverse branch of the lateral femoral circumflex artery. All 65 flaps survived and none showed partial necrosis.

CONCLUSIONS

The anterolateral thigh chimeric flap can be divided into 3 types: trunk type (I type), branch type (II type) and bifurcation type (III type).

Role of a two-step suture in the prevention of postoperative transoral salivary fistulas during reconstruction of the oral cavity

Transoral salivary fistulas are one of the most serious postoperative complications after operations for oral cancer, and we propose a new, two-step suture method to avoid them. From January 2005 to September 2017, 240 patients were recruited at the Shanghai Ninth People's Hospital and divided into experimental (n=89) or control (n=151) groups. The experimental group was treated by a two-step suture technique, while the control group had conventional sutures. Statistical differences were assessed using the chi squared and t tests, as appropriate. Only two patients developed transoral salivary fistulas in the experimental group, while in the control group there were 14 (9%). The incidence of fistulas in the experimental group was significantly lower than that in the control group (p=0.035). Regression analysis showed that there was a significant correlation between the groups and the incidence of salivary fistulas (p=0.032). The two-step suture technique is safe, effective, and easy to learn, and could reduce the incidence of postoperative salivary fistulas.

Prediction of Flap Compromise by Preoperative Coagulation Parameters in Head and Neck Cancer Patients

PURPOSE

Studies on coagulation parameters (including activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen [FIB], platelet count, and D-dimer) in flap compromise are limited. The aim of the present study was to compare coagulation parameter variables in patients with and without flap compromise.

MATERIALS AND METHODS

In this retrospective cohort study, patients were recruited from the Department of Oral and Maxillofacial Surgery at the Second Xiangya Hospital (Changsha, Hunan, China) from July 2016 through July 2017. The primary predictor variable was a set of coagulation parameters. The primary outcome variable was flap compromise. The other variables were age, gender, tumor stage, smoking, and prior radiotherapy. Descriptive, bivariate, receiver operating characteristic (ROC) curves and regression statistics were computed. Statistical significance was set at less than .05 with 95% reliability.

RESULTS

A total of 503 patients with 42 compromised flaps were identified in this study. Venous thrombosis, arterial thrombosis, or no confirmed reason for compromise was observed in 28, 5, or 9 compromised flaps, respectively. Only FIB was associated with flap compromise or venous thrombosis at adjusted analyses, although the predictive values were low at ROC analysis. For patients with D-dimer lower than 0.4 μg/mL, the likelihood of venous thrombosis was greater than that for patients with D-dimer of at least 0.4 μg/mL (P = .0414). For patients with FIB lower than 3.5 g/L, the likelihood of venous thrombosis was greater than that for patients with FIB of at least 3.5 g/L (P = .0336).

CONCLUSION

Decreased FIB was associated with a higher rate of flap compromise. In patients with D-dimer lower than 0.4 μg/mL or FIB lower than 3.5 g/L, the risk of venous thrombosis was higher.

Unit resection of buccal squamous cell carcinoma: Description of a new surgical technique

This study characterized the infiltration of primary tumors along the muscles, fascia and spaces of the maxillofacial region in buccal squamous cell carcinoma (BSCC) and suggested a new surgical strategy that is suitable for most stages. Based on the anatomic characteristics and infiltration of the primary tumor a new surgical approach - unit resection buccal surgery (URBS) - was developed. We evaluated this new surgical strategy, across a cohort of 127 BSCCs: 60 cases treated with URBS and 67 cases treated with conventional surgery. Notably there was no statistical difference in the clinicopathological variables between the two groups. After initial treatment with curative intent, the patients were regularly followed-up with clinical examination and imaging. URBS proved suitable for almost all stages of BSCC, and was particularly advantageous for advanced stages of BSCC. At 2 years post-treatment, the rates of overall survival were 83.3% in the URBS group and 60.1% in the conventional surgery group, respectively (hazard ratio 0.38; 95% CI 0.20 to 0.75; P=0.005). Similarly, the rates of disease-free survival were 76.6% and 51.9% in the URBS group and the conventional surgery group, respectively (hazard ratio 0.42; 95% CI 0.23 to 0.75; P=0.003). The principles of URBS are suitable for almost all stages of BSCC, especially advanced stages. URBS may improve the prognosis of BSCC patients.

CD73 is associated with poor prognosis in HNSCC

CD73 is a cell surface immunosuppressive enzyme involved in tumor progression and metastasis. While patients whose cancer cells express elevated CD73 are typically associated with an unfavorable outcome, the clinical impact of CD73 expression in patients with Head and neck squamous cell carcinoma (HNSCC) remains unclear. In the present study, we investigated the prognostic significance of CD73 in HNSCC using gene and protein expression analyses. Our results demonstrate that high levels of CD73 are significantly associated with reduced overall survival in patients with HNSCC. We also investigated the functional role of CD73 in vitro and demonstrated that CD73 promotes HNSCC migration and invasion through adenosine A3R stimulation and the activation of EGF/EGFR signaling. Moreover, in vivo xenograft studies demonstrated that CD73 promotes tumorigenesis. In conclusion, our study highlights a role for CD73 as a poor prognostic marker of patient survival and also as a candidate therapeutic target in HNSCCs.