Mi Hyun Seo

Osteogenetic changes in elongated styloid processes of Eagle syndrome patients

Abnormal elongation of the styloid process, or Eagle syndrome, can be painful, and is associated with differential diagnoses including cranio-facial malformations and vasculo-neurological disturbances. The precise molecular mechanism leading to styloid process elongation is unknown. In this study, elongated styloid processes with periosteal fibrous ligament tissue were obtained from three patients with Eagle syndrome and examined by immunohistochemical methods using different antisera. In all cases, marked bony deposition was found at the apex of the styloid process. The osteogenetic proteins, such as osteonectin, osteocalcin, BMP-2, BMP-4, and RANKL were strongly positive by immunohistochemistry in both the ligament fibers and the periosteal membrane attached to the styloid process apex. Staining for protective proteins, HO-1, HSP-70, and HSP-90 was also positive. These results suggest that styloid process elongation is related to increased expression of osteogenetic and protective proteins. Therefore, we propose that Eagle syndrome results from a protective response to increased tensile stress in the ligament attached to the styloid process, which could also signal osteogenetic protein expression in the periosteal fibrous tissue.

Analysis of Microvascular Free Flap Failure Focusing on the Microscopic Findings of the Anastomosed Vessels.

AbstractMicrovascular flap reconstruction is known as successful technique, although vascular thrombosis can cause free flap failure. To analyze the histologic characteristics and causes of free flap failure, this clinical study examined failed free flaps, including the microanastomosed sites.This study included a total of 5 failed flaps, including 3 radial forearm free flaps, 1 latissimus dorsi free flap, and 1 fibular free flap, all performed with microvascular reconstruction surgery from 2009 to 2011 at Seoul National University Dental Hospital. At the resection surgeries of the failed nonviable flaps, histologic specimens including the microanastomosed vessels were acquired. For light microscope observation, the slides were stained with hematoxylin and eosin (HE), and also with Masson trichrome. Selected portions of graft tissue were also observed under transmission electron microscope (TEM).It was found that the cause of flap failure was the occlusion of vessels because of thrombi formation. During the microanastomosis, damage to the vessel endothelium occurred, followed by intimal hyperplasia and medial necrosis at the anastomosed site. In the TEM findings, some smooth muscle cells beneath endothelium were atrophied and degenerated. The formation of thrombi and the degeneration of the smooth muscle cells were coincident with vascular dysfunction of graft vessel.The damaged endothelium and the exposed connective tissue elements might initiate the extrinsic pathway of thrombosis at the microanastomotic site. Therefore, it is suggested that accurate surgical planning, adequate postoperative monitoring, and skillful technique for minimizing vascular injury are required for successful microvascular transfer.

Influence of vascular twisting on the supermicroanastomosis of superficial inferior epigastric artery.

Abstract Arterial microanastomoses with small-caliber vessels, such as those with an internal diameter less than 0.2 mm, are susceptible to inadvertent twisting. A total of 20 supermicroanastomoses were performed in the superficial inferior epigastric artery (SIEA)–based flap model of ten 10-week old, 300- to 350-g male Sprague-Dawley rats. Two rats with 4 flaps comprised each experimental group: a negative control, a control with end-to-end SIEA arterial supermicroanastomosis, and 3 experimental groups (EAs), such as EA1, 2, and 3 with 90-, 180-, and 270-degree twisting supermicroanastomosis, respectively. Each SIEA was clamped with a Superfine Vascular Clamp (S&T Co, Neuhausen, Switzerland) and anastomosed with 6 stitches. On postoperative day 10, the skin flap surface texture had no color change, and skin necrosis was not found in any group within a 1.0-mm grid measurement in less than 1% of the whole skin flap surfaces. There were statistically significant differences between the groups in 4 criteria, such as cellular swelling, nuclear pleomorphism, nuclear swelling, and microvessel numbers. The pulsatility index was increased in the EA1 and EA2 on postoperative days 1 and 2, showing decrease in the similar preoperative value on postoperative day 10, but decreased pulsatility index was continuous in the EA3 during the postoperative day 10. The resistance index was significantly different between preoperative and postoperative day 10 especially in the EA2 and EA3. Ultramicroscopic findings in the EA3 group showed an increase in tunica media necrosis, convolution of the internal elastic lamina, and densely packed platelets, fibrins, and erythrocytes.

Regional anesthesia for maxillofacial surgery in developing countries

Regional anesthesia in the maxillofacial region is safer and more efficient than general anesthesia when its indications are carefully considered. In addition, the majority of medical institutions in developing countries are not well equipped for proper anesthesia and elective surgery. In this review, we describe regional anesthesia and cutaneous nerve divisions in the maxillofacial region. In addition, we summarize detailed regional anesthetic techniques adapted for representative cleft lip cases in developing countries.