Free Flap Survival with External Jugular Vein as a Detour Due to Internal Jugular Vein Thrombosis.

In head and neck reconstructions, venous anastomosis of the free flap to the internal jugular vein system is a common procedure. However, in some cases, postoperative complications such as internal jugular vein thrombosis can occur. In this report, we present a case where postoperative internal jugular vein thrombosis was identified after venous anastomosis of the free flap to the internal jugular vein system. In this case, preserving the external jugular vein allowed for retrograde flow of venous blood in the internal jugular vein to enter the external jugular vein, serving as an alternative drainage pathway. This finding highlights the potential benefits of preserving the external jugular vein in head and neck surgery involving free flap venous anastomosis to mitigate the adverse effects of internal jugular vein thrombosis. Further investigations are warranted to better understand the underlying mechanisms and optimize surgical approaches for improved patient outcomes.

Schlieren Phenomenon for Identification of Lymphorrhea Point.

Surgical invasion of the lymphatic system can lead to lymphorrhea. Lymphorrhea is first treated conservatively, but is often refractory and subsequently treated surgically. In surgery, it is difficult to identify the lymphatic leak points visually. In this study, we observed the schlieren phenomenon based on the difference in the refractive index between glucose solution and lymph fluid, and were able to easily identify the site of the lymphatic leakage in real time and treat lymphorrhea.

Efficacy of gelatin hydrogels incorporating triamcinolone acetonide for prevention of fibrosis in a mouse model.

INTRODUCTION: Triamcinolone acetonide (TA), a steroid, is often used clinically to prevent dysfunctions associated with fibrosis. The objective of this study was to examine whether TA can be suspended in a gelatin sheet for tissue engineering using a mouse skin wound model. METHODS: TA was suspended in biodegradable gelatin and freeze-dried in a sheet form. The sheet was analyzed for homogeneity and controlled release of TA by high-performance liquid chromatography. We made two skin wounds on the dorsal side of mice. Gelatin sheets with TA (TA sheet) and without TA (control sheet) were attached to each skin wound. To determine the efficacy of the prepared TA sheet on the skin wounds, TA-sheet versus TA-injection experiments were conducted. Hematoxylin and eosin staining was performed to assess the grade of epithelialization and alpha smooth muscle actin (α-SMA) immunohistochemical staining was conducted to evaluate myofibroblast infiltration. RESULTS: In the TA-release test in vitro, 7.7 ± 2.3% of TA was released from the sheet by 24 h. After replacing the initial phosphate-buffered saline (PBS) with collagenase PBS, the amount of released TA increased over time. The wound area/original skin wound area after 15 days with the TA sheet was significantly larger than that with the control sheet (26.9 ± 5.5% vs 10.7 ± 2.6%, p = 0.023). The α-SMA positive area/whole area with the TA sheet was significantly lower than that with the control sheet (4.65 ± 0.66% vs 7.24 ± 0.7%, p = 0.023). Furthermore, the α-SMA positive area/whole area with the TA sheet was significantly lower than that with TA injection (5.32 ± 0.45% vs 7.93 ± 0.75%, p = 0.013). CONCLUSIONS: We developed a TA sheet and confirmed both the homogeneity of the suspended TA and controlled-release of the TA in the presence of collagenase in vitro. The TA sheet caused less myofibroblast infiltration into the tissue than the control sheet or TA injection did.

Development of a mouse nerve-transfer model for brachial plexus injury.

Nerve transfer involves the use of a portion of a healthy nerve to repair an injured nerve, and the process has been used to alleviate traumatic brachial plexus injuries in humans. Study of the neural mechanisms that occur during nerve transfer, however, requires the establishment of reliable experimental models. In this study, we developed an ulnar-musculocutaneous nerve-transfer model wherein the biceps muscle of a mouse was re-innervated using a donor ulnar nerve. Similar muscle action potentials were detected in both the end-to-end suture of the transected nerve (correctrepair) group and the ulnar-musculocutaneous nerve-transfer group. Also, re-innervated acetylcholine receptor (AChR) clusters and muscle spindles were observed in both procedures. There were fewer re-innervated AChR clusters in the nerve transfer group than in the correct repair group at 4 weeks, but the numbers were equal at 24 weeks following surgery. Thus, our ulnar-musculocutaneous nerve-transfer model allowed physiological and morphological evaluation for re-innervation process in mice and revealed the delay of this process during nerve transfer procedure. This model will provide great opportunities to study regeneration, re-innervation, and functional recovery induced via nerve transfer procedures.