Yu Takayama

Double Free Flap Transfer using a Vascularized Free Fibular Flap and a Rectus Abdominalis Musculocutaneous Flap for an Extensive Oromandibular Defect: Prevention of Sinking or Drooping of the Flap With an Anterior Rectus Sheath.

The double free flap procedure is a preferred treatment for extensive composite defects of the oromandibular area. In this procedure, the choice and use of the flaps are both important. Flaps with adequate soft tissue are required to fill the extensive dead space for huge oromandibular defects. Such flaps, however, tend to sink and droop with time because of gravity, resulting in poor functional and aesthetic results. Here, the authors describe a procedure that avoids flap sinking and drooping, using a vascularized fibular osteocutaneous flap, which is well established for mandibular bone defects, and a rectus abdominalis musculocutaneous flap, which has a lot of soft tissue and a firm anterior rectus sheath. This method was used in 2 patients with extensive composite defects of the oromandibular area. In a patient with resection of the mobile tongue and oral floor, the anterior rectus sheath was fixed to the fibula and mandible to give a mylohyoid muscle-like structure, to prevent sinking of the reconstructed oral floor and tongue. Good swallowing function was maintained. In a patient with defects transversally from the submandibular region to the cheek, the sheath was fixed to the zygomatic arch to prevent cheek drooping. An acceptable aesthetic result was obtained.

Lower lip repair using double opposing rectangular rotation flaps with reconstruction of the mentolabial groove and mental protuberance

The use of a rectangular flap is a well known technique for upper lip repair in cleft lip, but is less common for lower lip repair after tumour resection. We have found this type of flap to be favourable for lower lip reconstruction, especially for the lip to mental region. We describe herein an improvement to the technique in which two opposing rectangular flaps, with the length of one side equal to the vertical distance from the mentolabial groove to the vermilion border, were raised on the lateral sides of a U-shaped defect. Reconstruction was performed by interdigitation of the two flaps and a bilateral vermilion advancement flap. This new approach allows a distinct mentolabial groove and mental protuberance to be created by utilizing two opposing rectangular flaps and redundant tissue, without sacrificing sensation and muscle function. Our results suggest that the technique provides excellent functional and cosmetic outcomes in restoration of the lower lip in properly selected patients.

Clinicopathological investigation of odontogenic fibroma in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant inherited disease characterized by systemic hamartoma and diverse systemic features. TSC1 and TSC2 are the causative genes, and mental retardation, epileptic seizures, and facial angiofibroma develop in many patients with the disease. The case of a patient with TSC who developed a central odontogenic fibroma of the mandible is reported here. The patient was a 21-year-old woman who was referred with a swelling of the labial gingiva in the region of the right lower lateral incisor and canine. Dental radiography revealed a multilocular radiolucent region with a clear boundary. The right lower lateral incisor and canine were continuous with the lesion and thus were excised en bloc. The lesion was encapsulated and easily dissected. The diagnosis on immunohistological staining was odontogenic fibroma without an epithelial component. TSC1/2 gene mutation causes abnormal activation of mammalian target of rapamycin (mTOR) downstream of the PI3K-AKT pathway. The odontogenic fibroma in this patient was positive for mTOR, suggesting that the development of the odontogenic fibroma was the result of abnormal activation of mTOR, as in angiofibroma. The clinical course of this patient is presented and the developmental mechanism of central odontogenic fibroma is discussed.

A Case of a Carcinoma ex Pleomorphic Adenoma in the Submandibular Gland

Carcinoma ex pleomorphic adenoma (Ca ex PA) is a carcinoma arising from a primary or recurrent benign pleomorphic adenoma. In this report, we present a case of a minimally invasive Ca ex PA arising in the submandibular gland. The patient was a 62-year-old man with a chief complaint of pain in the right submandibular region. The clinical diagnosis was a benign tumor in the submandibular gland and surgical resection was performed. The tumor contained a small amount of tumor-cell components, and showed a malignant area and a benign area. The malignant area was poorly differentiated adenocarcinoma, immunohistochemically the tumor cells were positive for HER2, and the Ki-67 labeling index was about 60%. The extent of capsular invasion was 1.4 mm into the adjacent tissues. The benign area was pleomorphic adenoma, negative for HER2, and the Ki-67 labeling index was about 4%. The diagnosis was Ca ex PA, minimally invasive type, although there were nerve and vascular invasions and poor prognostic factors, such as positivity for HER2 and high-grade malignancy components. We performed post-operative radiotherapy. Careful clinical follow-up is necessary.

Motor Nerve Preservation and Muscle Atrophy After Pectoralis Major Musculocutaneous Flap Surgery for Oromandibular Reconstruction

Objective:The authors investigated the clinical and histopathologic significance of medial pectoral nerve preservation/reinnervation of pectoralis major musculocutaneous flap for oromandibular reconstruction. Materials and Methods:The authors compared 13 patients treated with pectoralis major musculocutaneous flap reconstruction and 6 control patients treated by rectus abdominis musculocutaneous flap reconstruction without motor nerve restoration. Subjective awareness was scored to evaluate changes in the facial contour due to muscle atrophy, and objective evaluation was performed in few patients. In addition, the authors performed histopathologic analysis of both muscle atrophy and nerve regeneration in 20 patients from whom samples were available. Results:Subjective awareness of changes in the facial contour induced by muscle atrophy was low among patients with nerve preservation/reinnervation, but there were objective changes at 3 months after surgery among patients who underwent nerve resection. In the patients who had medial pectoral nerve preservation or nerve restoration by nerve suture, favorable facial symmetry was retained at 5 years after surgery. Even though the motor nerve was preserved or restored, fatty degeneration and fibrosis were noted in approximately 30% of the total surface area of the muscle, and type I fibers had decreased to 36% that of control at 7 years after surgery. However, regressive changes were inhibited for 1 year after surgery; in contrast, changes corresponding to those noted at 7 years after surgery were observed by 3 months in the patients with nerve resection. Conclusion:Thus, the authors showed that preservation or restoration of nerves can delay muscle and have highlighted the potential benefits of this approach.