Kazumichi Yonenaga

Computer-assisted preoperative simulation for positioning of plate fixation in Lefort I osteotomy: A case report

Computed tomography images are used for three-dimensional planning in orthognathic surgery. This facilitates the actual surgery by simulating the surgical scenario. We performed a computer-assisted virtual orthognathic surgical procedure using optically scanned three-dimensional (3D) data and real computed tomography data on a personal computer. It helped maxillary bone movement and positioning and the titanium plate temporary fixation and positioning. This simulated the surgical procedure, which made the procedure easy, and we could perform precise actual surgery and could forecast the postsurgery outcome. This simulation method promises great potential in orthognathic surgery to help surgeons plan and perform operative procedures more precisely.

Implant-type Tissue-engineered Cartilage for Secondary Correction of Cleft Lip-nose Patients: An Exploratory First-in-human Trial

Objective: Secondary correction of cleft lip-nose presents a formidable challenge in cleft lip and palate surgery. Although numerous approaches have been proposed, suitable graft materials cannot be obtained from any part of body or the artificial biomaterials. We have established implant-type tissue-engineered cartilage using a porous scaffold comprised of poly L-lactic acid. The aim of this study was to primarily assess the safety of the autologous tissue-engineered cartilage when used in the cleft lip-nose patients as an exploratory first-in-human trial, and to explore the usefulness of the cartilage. Methods: After the acquisition of institutional and governmental permission, we used this implant-type tissueengineered cartilage for the treatment of three cleft lip-nose patients. We examined whether or not serious adverse events had occurred by which removal of the tissue-engineered cartilage was needed, 3 years after the transplantation. We also explored the usefulness of the cartilage, as aesthetic and functional outcomes. Results: Each tissue-engineered cartilage fulfilled the defined release criteria for transplantation. The transplantation of the tissue-engineered cartilage in all the patients was performed just as planned. After 3 years of transplantation, we did not experience any serious adverse events that were related to the tissue-engineered cartilage. As a non-serious adverse event, calcification of the tissue-engineered cartilage was found in one patient. Nose shapes improved in all the patients, and more than 2 mm of nose augmentation maintained for 3 years postsurgery, as measured in cephalogram. Although the dysfunction in facial expression or playing sports had rather increased immediately after the transplantation, the inconvenience generally recovered or improved during the postsurgical course. Conclusion: The implant-type tissue-engineered cartilage could safely reconstruct the nasal dorsum and apex of cleft lip-noses. This tissue-engineered cartilage possibly leads to effective correction of a severe cleft lip-nose deformity with aesthetic and functional improvement.

Computer-assisted preoperative simulation for positioning and fixation of plate in 2-stage procedure combining maxillary advancement by distraction technique and mandibular setback surgery

Highlights • Reported a case of maxillary retrusion by a bilateral cleft lip and palate.• Preoperative simulation was performed for positioning and fixation of plate.• Maxillary advancement by distraction technique and mandibular setback surgery.• 2-stage procedure with maxillary advancement was found to be accurate.

Three-dimensional changes of noses after transplantation of implant-type tissue-engineered cartilage for secondary correction of cleft lip–nose patients

Introduction We have developed an implant-type tissue-engineered cartilage using a poly-l-lactide scaffold. In a clinical study, it was inserted into subcutaneous areas of nasal dorsum in three patients, to correct cleft lip–nose deformity. The aim of this study was to helping evaluation on the efficacy of the regenerative cartilage. Methods 3D data of nasal shapes were compared between before and after surgery in computed tomography (CT) images. Morphological and qualitative changes of transplants in the body were also evaluated on MRI, for one year. Results The 3D data from CT images showed effective augmentation (>2 mm) of nasal dorsum in almost whole length, observed on the medial line of faces. It was maintained by 1 year post-surgery in all patients, while affected curves of nasal dorsum was not detected throughout the observation period. In magnetic resonance imaging (MRI), the images of transplanted cartilage had been observed until 1 year post-surgery. Those images were seemingly not straight when viewed from the longitudinal plain, and may have shown gentle adaptation to the surrounding nasal bones and alar cartilage tissues. Conclusion Those findings suggested the potential efficacy of this cartilage on improvement of cleft lip–nose deformity. A clinical trial is now being performed for industrialization.

Optimal conditions of collagenase treatment for isolation of articular chondrocytes from aged human tissues

Introduction There are various types of cartilage, including the auricular and articular cartilages. These cartilages have different functions, and their matrix volume and density of chondrocytes may differ. Thus, different protocols may be required to digest different types of cartilage. Methods In this study, we examined protocols for the digestion of articular and auricular cartilages and determined the optimal conditions for articular cartilage digestion. Results Our histological findings showed that the articular cartilage has a larger matrix area and fewer cells than the auricular cartilage. In 1-mm2 areas of articular and auricular cartilages, the average numbers of cells were 44 and 380, respectively, and the average matrix areas were 0.94 and 0.77 mm2, respectively. The maximum numbers of viable cells (approximately 1 × 105 cells/0.1 g of tissue) were obtained after digestion in 0.15, 0.3, or 0.6% collagenase for 24 h, in 1.2% collagenase for 6 h, or in 2.4% collagenase for 4 h. In tissues incubated in 0.15 or 0.3% collagenase, the cell numbers were lower than 1 × 105, even at 24 h, possibly reflecting incomplete digestion of cartilage. No significant differences were observed in the results of apoptosis assays for all collagenase exposure times and concentrations. However, cell damage appeared to be greater when collagenase concentrations were high. When cells obtained after digestion with different concentrations of collagenase were seeded at a density of 3000 cells/cm2, they yielded the maximum cell numbers after 1 week. Conclusions We recommend a 24-h incubation in 0.6% collagenase as the optimal condition for chondrocyte isolation from articular cartilage. Moreover, we found that the optimum cell-seeding density is approximately 3000 cells/cm2. Conditions determined in this study would maximize the yield of isolated articular chondrocytes and enable the generation of a large quantity of cultured cells.

Ossification of the anterior longitudinal ligament observed during upper endoscopy for dysphagia

Abstract The patient was a 78-year-old man with a chief complaint of dysphagia. Extrinsic displacement of the posterior hypopharyngeal wall was observed on upper endoscopy. The patient was diagnosed with ossification of the anterior longitudinal ligament (OALL) of the cervical spine according to lateral cervical spine radiographic findings. The OALL caused dysphagia. In swallowing endoscopic assessments of patients with dysphagia, OALL of the cervical spine should be differentiated from other possible diagnoses by using radiography when extrinsic displacement of the posterior oropharyngeal or hypopharyngeal wall is observed.