Published papers

Purpose: Posterior cranial vault distraction profoundly enlarges intracranial volume. To perform this procedure during the first year of life, the cranium is too thin to fix the distractors. Sometimes, the screws penetrate the bone, which risks scratching the dura during distraction. To solve this problem, we developed an implant fixation technique using bioabsorbable screws and plates, and named it the GETA technique.Methods: In cases in which the bone is thinner than the screws, a resorbable sheet is placed between the bone and the dura to protect the dura from the tips of the screws.Results: We used this technique for cranial distraction in four patients, with satisfactory results and without complications.Conclusions: The technique described here allows craniofacial surgeons to fix the distractors without injuring the dura.

BACKGROUND: Simulated craniomaxillofacial surgery is critical for planning the procedure, shortening operative time, and practicing the procedure. However, typical models are expensive, given their solid materials, and the surgical sensations do not accurately reflect the procedure performed using human bone. To solve these problems, a new solid salt model has been developed.METHOD: Stereolithography data was generated using computed tomography data, and a salt model was created using a 3D inkjet printer. By extracting specific data for elements such as the teeth and mandibular canal, these elements were highlighted in the solid model using different colored material. Also, we compared the maximum load and plastic deformation of the salt model, a stereolithographic resin model, and a pig limb.RESULT: The salt model had similar tenacity to bone, and the risk of damage to the teeth and inferior alveolar nerve was easily confirmed.CONCLUSION: The material cost of the salt model is extremely low, and the salt model may provide a more accurate sensation of cutting human bone. Thus, this model is useful for both simulated operation and practice for inexperienced surgeons.

Objective Current imaging techniques for velopharyngeal closure (VPC) evaluation are two-dimensional, static, or distressing, thus necessitating multiple procedures to understand this three-dimensional and dynamic area. We validated the use of a novel four-dimensional (4D) computed tomography (CT) technique for the morphological and kinematic evaluation of VPC in cleft palate patients based on dynamic volume scanning with 320-detector-row CT. Methods Five patients aged 4-10 years (40% males) with persistent velopharyngeal insufficiency post palatoplasty underwent conventional tests (cephalometry and video-nasal endoscopy) and 4D-CT. For each patient, complete multiplanar reconstruction, 4D airway CT, and 4D-CT endoscopy data for all scanning phases were compared with cephalometric and video-nasal endoscopy data. The movements of the velum and posterior pharyngeal walls were graded by each modality. Results 4D airway CT revealed higher anatomical detail than cephalometry, additionally providing dynamic images. 4D-CT endoscopy and video-nasal endoscopy were in agreement for all patients regarding the patterns of VPC, with complete visualization of VPC in five versus one patient, respectively. 4D airway CT and cephalometry showed a discrepancy in one case, wherein grading by cephalometry was overestimated. 4D-CT was also useful in determining the width and length of a proposed pharyngeal flap. The examination time (mean ± standard deviation (SD), seconds), including patient preparation time, was 224 ± 73, 492 ± 145, and 718 ± 123 for cephalometric radiographs, CT, and video-nasal endoscopy, respectively. The mean estimated radiation dose during 4D-CT was 4.44 ± 1.64 mSv. Conclusions 4D-CT provides detailed morphological and kinematic analysis of VPC and may offer advantages over conventional procedures.

The development of an effective rat model of incisional surgical site infection (SSI) has so far proven difficult. In this study, we created a novel incisional SSI model and validated it in terms of both macroscopic and microscopic aspects including its response to treatment using antimicrobial wound-dressing, Aquacel Ag®. Wounds were created on the dorsum of rats. 3-0 Vicryl®threads inoculated with Escherichia coli were inserted in the wound beds in the infection group (n=6). The wounds were closed for two days to induce infection and then opened and covered with polypropylene sheets during the study. Aquacel Ag was placed under the polypropylene sheet in the infected wounds of the Aquacel Ag group rats (n=6). The wounds in the control group (n=6) contained sterile Vicryl thread that had not been inoculated with E. coli. The macroscopic appearance, wound area, bacterial counts, and histology of each group were evaluated. The infection group demonstrated significantly lower wound healing (p<0.001), greater bacterial counts (median [interquartile range] ratings, 2.15×107 [0.51×107-53.40×107] vs 2.07×104 [0.60×104-4.45×104]CFU/g, respectively; p<0.01), and severer histological inflammation (p<0.001) than the control group. The Aquacel Ag group was only able to show significantly better wound healing than the infection group (p<0.001). The new incisional SSI model exhibited all clinical manifestations of incisional SSI. It could be utilized to assess the effectiveness of newly developed treatments for incisional SSI.

Chronic expanding haematoma (CEH) is a rare type of haematoma that enlarges slowly and continuously without coagulation. It can occur following surgery because of shear stress-induced bleeding in the scar tissue between the subcutaneous fat and fascia. We present three cases of large chronic CEH that were successfully treated with triamcinolone injections. Three female patients developed large chronic CEH at 9 months, 5 years, and 6 years, respectively, after latissimus dorsi flap harvesting for breast reconstruction. Although the condition did not improve after multiple sessions of haematoma aspiration in the first two patients, it resolved following a single 40-mg triamcinolone injection along with appropriate compression dressing for several weeks. In the third patient, triamcinolone was injected immediately after the initial aspiration of the haematoma, and the condition improved considerably. There were no side effects in any of the patients. To the best of our knowledge, this is the first report of successful treatment of large CEH using triamcinolone. Therefore, we suggest that triamcinolone injections be considered for the treatment of CEH.

Cranioplasty using custom-made hydroxyapatite (HAP) ceramic implants is a common procedure to repair skull defects. However, commercially available titanium screws are only minimally stabilized due to characteristic brittleness. We developed the RIVET technique which involves fixing a bioabsorbable plate atop a HAP block using bioabsorbable screws extending beyond both layers, and evaluated fixation strength using the pull-out test and microtomography. Three experimental conditions were compared: a non-RIVET group, RIVET group, and dry skull control group. Pull-out strength significantly differed across groups (non-RIVET group, 1.33 ± 1.21 kgf; RIVET group, 4.46 ± 0.84 kgf; and control group, 6.99 ± 1.14 kgf, P < 0.01). Microtomography of the dry skull control group revealed thread grooves fitted to the screws. The non-RIVET and RIVET groups presented fewer thread grooves than the control group, and the screws did not fit perfectly to the HAP block. However, fixation in the RIVET group was more stable, as the rivet was firmly lodged into the implant. In conclusion, by melting and creating the rivet, pull-out strength can be increased and rigid stabilization of HAP can be obtained. This technique uses commercially available absorbable plate and screws, and thus can be used widely in clinical applications involving HAP blocks with different porosities and thicknesses.

Myoepithelioma is a rare, benign salivary neoplasm, most frequently located in the salivary gland; extrasalivary cases most commonly occur in the palate. This tumor is prone to recurrence. We present a case of recurrent myoepithelioma in the nasal cavity with a palatal fistula treated both by a palatal approach and a piriform apertural approach. The combination of these approaches widens the surgical space, allowing removal of the mass. It is important not only to excise the mass but also to allow for reconstruction.

Post-traumatic hyperpigmentation (PTH) is a common symptom after skin injuries in Asians. PTH occurs on scars or skin following acute inflammation. PTH is classified into the following three conditions based on the pigmented lesions : an increase of epidermal melanin due to the activation of epidermal melanocytes after inflammation, incontinentia pigmenti histological, and dermal implantation of foreign substances known as a "traumatic tattoo". LLLT and LED irradiation are effective methods for controlling skin inflammation. The increase in epidermal melanins. known as basal hyperpigmentation. gradually disappears within 6-12 months. To shorten the treatment period, topical bleaching ointments such as hydroquinone. tretinoin, and vitamin C as well as IPL/long-pulsed alexandrite laser treatments are available. In the case of incontinentia pigmenti histological, which involves chronic inflammation in the skin, the basement membrane is partially destroyed and epidermal melanins are "dropped" into dermal lesions. These dropped melanins are digested by macrophages, which remain as melanophages in the dermal lesions for several years, and so this type of dermal pigmentation does not disappear spontaneously. Therefore, Q-switched lasers are used for the selective treatment of dermal hyperpigmentation. For the treatment of PTH, personalized, appropriate therapeutic planning based on a precise diagnosis is important.

Frontalis suspension using autogenous fascia lata is a common procedure for blepharoptosis with poor levator function. However, donor-site morbidity associated with fascia lata harvest cannot be ignored. In conventional procedures, the required length of the fascia lata is usually >5-12 cm with a lateral thigh skin incision of approximately 5 cm or more. The present study introduces a new frontalis suspension procedure in which the required size (length and width) of the fascia lata and length of lateral thigh incision is much smaller. The harvested fascia lata is tailored to an inverted Y shape and the separated caudal legs are fixed to the tarsus while the cephalic end is grafted inside the eyebrow through a suborbital septum tunnel. In the present study, 11 patients who underwent the new procedure with a minimum of 6 months of follow-up were evaluated. The average length and width of the harvested fascia lata in unilateral ptosis cases were 2.85 and 0.89 cm, respectively. The average length of the lateral thigh incision was 1.25 cm. The margin reflex distance improved in all cases at 6 months postoperatively. The cosmetic result was graded as good to excellent in most of the patients. Trichiasis, widened donor scar, and eyebrow notch were noted as complications. The present method is a good alternative for the treatment of blepharoptosis with poor levator function. It potentially reduces donor-site morbidity as compared with conventional frontalis muscle suspension procedures using autogenous fascia lata.

Background: The management of fronto-orbital fibrous dysplasia involves total excision of the dysplastic bone and bone reconstruction using implants. Custom-made implants are used to achieve good contouring. However, the remnant defect after excising the lesion often does not match the implant. Methods: To design the craniotomy line, a template was prepared by preoperative computed surgical simulation. The template was overlaid on the preoperative cranium, such that its inner surface fits exactly with the cranial surface. After excising the lesion by performing osteotomy, the implant was placed in the defect and fixed. Both template and implant were made of hydroxyapatite. Results: The authors treated 4 patients, with fibrous dysplasia involving the fronto-facial region by using the template. Intraoperative trimming of the implant or bone defect was not required in 2 patients, while the third patient required mild trimming. They did not have any complications and obtained good contouring. Conclusion: The hydroxyapatite templates reduced the surgical time by determining the precise craniotomy line preoperatively, thus avoiding needless trimming of the implant and bone defect. Therefore, they can enhance the efficacy of treatment for fronto-orbital fibrous dysplasia lesion.

Background Flap volume is an important factor for obtaining satisfactory symmetry in breast reconstruction with a transverse rectus abdominis myocutaneous (TRAM) free flap. We aimed to develop an easy and simple method to estimate flap volume. Methods We performed a preoperative estimation of the TRAM flap volume in five patients with breast cancer who underwent 2-stage breast reconstruction following an immediate tissue expander operation after a simple mastectomy. We measured the height and width of each flap zone using a ruler and measured the tissue thickness by ultrasound. The volume of each zone, approximated as a triangular or square prism, was then calculated. The zone volumes were summed to obtain the total calculated volume of the TRAM flap. We then determined the width of zone II, so that the calculated flap volume was equal to the required flap volume (1.2×1.05× the weight of the resected mastectomy tissue). The TRAM flap was transferred vertically so that zone III was located on the upper side, and zone II was trimmed in the sitting position after vascular anastomosis. We compared the estimated flap width of zone II (=X) with the actual flap width of zone II. Results X was similar to the actual measured width. Accurate volume replacement with the TRAM flap resulted in good symmetry in all cases. Conclusions The volume of a free TRAM flap can be straightforwardly estimated preopera-tively using the method presented here, with ultrasound, ruler, and simple calculations, and this technique may help reduced the time required for precise flap tailoring.

Postoperative radiation can cause ulcer formation, leading to the denudation of skin over alloplastic materials. The influence of backscatter radiation from fixation devices has not been investigated. The aim of this study is to evaluate backscatter dose variations for different cranial bone fixation devices in an experimental model designed to simulate postoperative radiotherapy. The authors assessed the radiation backscatter doses associated with resorbable (PLLA-PGA) and titanium plates. The samples were irradiated with 6 and 10 MV photon beams from a linear accelerator. Measurements were obtained using an ionization chamber and radiochromic films cut from the same batch. As a result, the backscatter radiation of water and PLLA-PGA proportionally decreased as the depth increased. However, the backscatter radiation of the titanium plate increased just above the plate. This depth lies in the region of the scalp. Each material showed a dose of radioactivity that was higher at 10 MV than that at 6 MV. These devices showed a significant difference, which suggested that these materials amplified the dose compared with water at 6 MV. In conclusion, it is supposed that PLLA-PGA should be used to fix the cranium to decrease the potential for radiation ulcers.