Congenital Cheek Fistula: A Rare Case of Developmental Abnormality in the Buccal Area.

A congenital cheek fistula is a rare malformation in the buccal area. Here, we report the case of a congenital cheek fistula in a 50-year-old woman who visited our clinic with complaints of swelling and pain in her left cheek. Physical examination revealed a small hole in the left corner of the mouth present since birth. She had no other congenital malformations in the maxillofacial region such as an accessory ear and cleft lip. Manual compression of the cheek mass induced serous discharge from the hole. Magnetic resonance imaging (MRI) showed a cystic lesion in the left cheek and a fistula within the orbicularis oris muscle that opened into the small hole. After immediate incision and drainage of the cyst, both the cyst and fistula were surgically resected. The cystic lesion was completely delineated from the boundary of the parotid gland. The orbicularis oris muscle was partially incised to remove the fistula and the surrounding scar tissue. Histopathological examination of the resected specimen revealed a cavity consisting of epithelium inside the fistula. The postoperative course was insignificant. No recurrence of the cyst was observed six months postoperatively. The operative and pathological findings demonstrated that the ectoderm-derived epithelial tissue was enclosed by the mesoderm-derived muscle tissue. The mixture of different germ layer-derived tissues suggested that the fistula was a type of congenital transverse facial cleft induced by malfusion of the mandibular and maxillary prominences during embryonic development. The differential diagnoses of the congenital cheek fistula included orocutaneous fistulas and salivary fistulas. MRI was useful in delineating the border between the lesion and the surrounding tissue.

Neural circuit analysis of axons regenerated by facial-hypoglossal nerve cross-link surgery.

INTRODUCTION: Several methods of nerve reconstruction for facial nerve palsy are known. Although the recently introduced method of "cross-linking" of the facial and hypoglossal nerves with a grafted nerve has proved efficacious, the underlying mechanism is unclear. METHODS: In this study, we created an animal model with Wistar rats and analyzed the newly reconstructed neural circuit by anterograde and retrograde neural tracer methods. The saphenous nerve was harvested as a graft, and its double end-to-side neurorrhaphy with the facial and hypoglossal nerves with epineural windows was carried out under the microscope. After an appropriate interval, small amounts of fluoro-ruby or fluoro-emerald were injected into the animals and analyzed 5 days later by fluorescent microscopy (Anterograde experiment: fluoro-ruby into the hypoglossal nucleus at 5 weeks; retrograde experiment: fluoro-ruby into the distal facial nerve sheath and fluoro-emerald into the distal hypoglossal nerve sheath, both at two months.). RESULTS: The labeled axons derived from the hypoglossal nucleus were observed passing through the grafted nerve to the facial nerve. On the other hand, retrogradely labeled neurons were observed at both the hypoglossal and facial nuclei with some double-labeled neurons, suggesting that collateral sprouting had occurred. CONCLUSIONS: We suggest that the newly constructed neural circuits we observed are conducive to the treatment of facial nerve palsy.

Development of a novel method for decellularizing a nerve graft using a hypertonic sodium chloride solution.

PURPOSE: Acellular nerves are a reconstruction material and provide scaffolds for nerve regeneration. Numerous methods to develop acellular nerves have been described. However, these methods pose problems that can be attributed to incomplete acellular processing and destruction of the extracellular matrix (ECM); the former may lead to rejection response, while the latter may damage the scaffold. In order to overcome problems associated with the above-mentioned methods, we developed a novel method that employs a hypertonic sodium chloride solution to decellularize nerve graft material. METHODS: Rat sciatic nerves were harvested, dipped in hypertonic sodium chloride solution (1 M), and shaken for 24 h. We then washed the nerves in phosphate-buffered saline for 7 days with shaking and evaluated the acellular nerves by hematoxylin-eosin (H-E) staining, immunostaining, and electron microscopy. We then transplanted the grafts to the sciatic nerve of another rat and evaluated the outcomes by H-E staining, immunostaining (anti-neurofilament antibody, anti-S-100 antibody), anterograde nerve tracing, and electron microscopy. RESULTS: We found that our method successfully decellularized the grafts, but was mild enough to leave the ECM intact. Two months after transplantation, immunostaining and anterograde nerve tracing confirmed that Schwann cells infiltrated the grafts and induced neurofilament extension. CONCLUSIONS: Our methodology preserves the ECM, is simple to develop, and does not involve substances that harm biogenic tissue. Acellular nerve tissue processed in this way could become a substitute material for bridging nerve gaps. Our method could also aid in the development of other acellular tissues.

Intima/medulla reconstruction and vascular contraction-relaxation recovery for acellular small diameter vessels prepared by hyperosmotic electrolyte solution treatment.

This study aims at the evaluation of blood vessel reconstruction process of decellularized small diameter vessels prepared by a hyperosmotic electrolyte solution treatment not only histologically but also physiologically in rat transplantation model. Complete cell removal by a hyperosmotic electrolyte solution treatment was confirmed by hematoxylin/eosin staining and scanning electron microscopic observation. All acellular vessels transplanted into the rat abdominal aorta were patent up to 14 months. One week post-transplantation, the vWF-positive cells were observed on the luminal surface but the layer formation did not complete. Five weeks following transplantation, the vWF-positive endothelial cells were located on the intima consistent with intact endothelial cells. Beneath the endothelial cells, α-SMA-positive smooth muscle cells were distributed. The harvested vessels displayed formation of tunica intima (endothelial cells) and tunica medulla (smooth muscle cell) layers. We also examined the physiological properties of the vessels 12 months post-transplantation using a wire myograph system. The transplanted vessels contracted upon addition of norepinephrine and relaxed upon addition of sodium nitroprusside as well as the native vessels. In conclusion, the acellular vessels prepared with hyperosmotic electrolytic solution showed excellent and long-term patency, which may be related to the successful preservation of vascular ECM. In addition, the acellular vessels revealed the intima/medulla regeneration with the physiological contraction-relaxation functions in response to the each substance.