[A Case of Reconstruction of the Osteoradionecrosis of the Jaw Using the Patient-Specific Custom-Made Cutting Guide and Mandibular Reconstruction Plate].

Multidisciplinary treatment, combining ablative surgery and reconstruction, radiotherapy, and chemotherapy, is used to treat advanced oral cancers. In this study, we report a case of extensive osteoradionecrosis of the mandible following multidisciplinary treatment for tongue cancer, in which a computer-assisted, patient-specific custom-made cutting guide and reconstruction plate(TruMatch® )were used to improve the patient's facial morphology and oral-maxillofacial functioning. A 70-year-old man received multidisciplinary treatment for squamous cell carcinoma of the left side of the tongue (cT3N2bM0, cStage ⅣA)at a previous hospital. Seven years postoperatively, bilateral osteoradionecrosis of the mandible developed, and the patient was referred to our department for further treatment. Since the lesions were extensive, we planned reconstructive surgery using the TruMatch® system in collaboration with the plastic surgery department of our hospital. Surgery was performed precisely and accurately according to the preoperative simulation. Postoperatively, the patient's recovery was uneventful. The TruMatch® system enables us to achieve good morphological and comprehensive functional oral-maxillofacial reconstruction.

[Effect of the Hyoid Bone Suspension Technique on the Preservation of Swallowing Function after Total Glossectomy and Pectoralis Major Musculocutaneous Flap Reconstruction for Locally Advanced Tongue Cancer].

Dysphagia is a major postoperative complication in patients with locally advanced oral cancer. In this case report, we describe the effect of the hyoid bone suspension technique on the preservation of swallowing function after total glossectomy and pectoralis major musculocutaneous flap reconstruction for locally advanced tongue cancer. Case: A 72-year-old Japanese male was diagnosed with advanced squamous cell carcinoma on the left side of his tongue(cT4aN2cM0, cStage ⅣA). Under general anesthesia, the patient underwent a tracheotomy, bilateral modified radical neck dissection type Ⅲ, total glossectomy, and reconstruction with a left pectoralis major musculocutaneous flap(PMMC flap). Intraoperatively, the PMMC flap was designed to have a heart shape of 11×6 cm and was elevated. Subsequently, holes were made at the lower edge of the mandible, and the hyoid bone was suspended and fixed to the mandibular border using 2-0 nylon sutures. The postoperative course was uneventful; the flap was completely engrafted and was in good condition. The hyoid bone suspension technique can reproduce the pharyngeal phase of swallowing, and the palatal augmentation prosthesis helps to improve food mass feeding and preserve the swallowing function.

[Surgical Treatment of Maxillary Gingival Carcinoma with Mental Retardation-A Case Report].

Many patients with mental retardation have a limited awareness of abnormalities in the oral cavity, making early detection of oral cancer difficult. Moreover, during examination and treatment, these patients may not understand well-intentioned verbal explanations and may express their anxiety through nonverbal communication. Herein we discuss a case in which favorable results were obtained when surgical treatment was performed on a maxillary gingival carcinoma patient with mental retardation. The patient was a 61-year-old man who was admitted to our hospital with maxillary gingival pain. A biopsy revealed well-differentiated oral squamous cell carcinoma(cT4aN0M0, Stage ⅣA). Hemi-maxillectomy was performed and postoperative recovery was uneventful. A maxillary prosthesis was provided for oral rehabilitation. At the 5-year follow-up, there were no signs of recurrence or metastasis. This case illustrates the importance of collaboration between oral maxillofacial surgeons and specialists from related departments for the comprehensive management of patients with mental retardation.

[A Case of Recurrent Squamous Cell Carcinoma of the Mandibular Gingiva Around a Mandibular Dental Implant].

Extensive bimaxillary bone support devices(hereafter referred to as a dental implant)are useful for morphological and functional reconstruction after resection of oral cancer. However, tumor recurrence due to peri-implantitis may occur. In this report, we describe a case of squamous cell carcinoma(SqCC)recurrence around a mandibular dental implant. An 80-year- old female patient underwent tumor resection and stratification for SqCC extending from the left lingual margin to the gingiva of the left lower molar in 2013. In 2014, 2 dental implants were placed in the bilateral mandibular canine region and a prosthetic device of implant-overdenture was installed. Six years after the primary tumor resection, a mass lesion was found in the peri-implant area of the left mandibular canine. Upon examination, the patient was diagnosed with SqCC recurrence and underwent radical tumor resection and immediate reconstruction using a submental flap and a reconstruction plate. Additional dental implants were concurrently placed in the remaining mandible. There was no evidence of recurrence, and the patient remains under careful observation so far.

[A Case of Polymorphous Low-Grade Adenocarcinoma of the Palate].

Polymorphous low-grade adenocarcinoma(PLGA)is a relatively rare low-grade adenocarcinoma of the minor salivary glands. If radical resection is performed, the prognosis is favorable. We present the case of a 62-year-old woman who presented to our clinic in April 2019 after noticing a mass on her palate. The intraoral examination revealed a 10-mm-diameter, well-defined, tender mass extending from the right hard palate to the soft palate. We suspected a benign tumor originating from the area of transition between the hard and soft palates. An excisional biopsy of the mass was performed, and PLGA was diagnosed on the basis of histopathologic findings. In May 2019, the tumor was resected under general anesthesia and a soft palatal lift prosthesis was applied for functional recovery. In July 2020, the soft palate defect was repaired using an ulnar forearm free flap during a two-stage reconstruction procedure. The patient developed complete necrosis of the free flap, and the defect was re-reconstructed using a buccinator-based myomucosal flap. There was no evidence of disease recurrence or metastasis. Two years have passed since the initial surgery, and the patient's clinical course has been well so far.

[A Clinical Study of Orofacial Defect Reconstruction Using a Modified Submental Island Flap following Oral Cancer Resection].

INTRODUCTION: Pedicled flaps are used in orofacial defect reconstruction in older patients and patients with underlying diseases. The submental island flap(SIF)is one type of cervical pedicled flap; however, the modified submental island flap (MSIF), which includes mylohyoid muscle, is a simpler and safer type. Here, we report a clinical study of orofacial defect reconstruction using the MSIF following oral cancer resection. PATIENTS AND METHODS: From January 2019 to December 2020, we retrospectively examined 10 cases of reconstruction using the MSIF following oral squamous cell carcinoma resection. RESULTS: The study population consisted of 7 men and 3 women with a mean age of 76.0(66-88)years. The primary sites were lower gingiva(n=5), tongue(n=3), and buccal mucosa in(n=2). Surgical procedures included marginal mandibulectomy( n=3), segmental mandibulectomy(n=1), partial glossectomy(n=2), hemiglossectomy(n=1), buccal mucosa resection(n=2), and combined partial glossectomy and segmental mandibulectomy(n=1). The average flap size was 61.4×36.0 mm. The average time of flap elevation was 32.4(23-50)minutes. During orofacial surgery using the MSIF, organs adjacent to the primary site could also be reconstructed. There were no complications in any patients. CONCLUSION: The MSIF is useful for orofacial defect reconstruction in older patients and patients with underlying diseases.

[Secondary Maxillofacial Revision Reconstruction Using Custom-Made Artificial Bone Following Resection of Primary Intraosseous Mandibular Squamous Cell Carcinoma and Microvascularized Fibula Flap Reconstruction].

The basic treatment for oral cancer is radical tumor resection and reconstruction, which alters the maxillofacial morphology and causes dysfunction. Reconstructive surgery can be performed with bone and soft tissue transplantation, but it is invasive and good morphological repair is difficult. Custom-made artificial bone(CT-BoneTM)consisting of calcium-deficient hydroxyapatite was newly authorized for clinical use in April 2018. It enables precise, minimally invasive maxillofacial bone reconstruction. Here, we report favorable facial morphological improvement using CT-BoneTM in a patient with maxillofacial asymmetry following the resection of a primary intraosseous mandibular squamous cell carcinoma and microvascularized fibula flap reconstruction. The patient was a 52-year-old woman. In August 2010, she was diagnosed with primary intraosseous mandibular squamous cell carcinoma of the right mandible(T4aN0M0, Stage ⅣA)and underwent mandibular segmental resection, neck dissection, and free fibula flap reconstruction. Although her clinical course was uneventful, she wanted maxillofacial esthetic correction. Therefore, we performed maxillofacial revision reconstruction using computer-simulated custom-made CT-BoneTM in January 2020. It was stably fixed to the reconstructed mandible with bioactive/bioresorbable screws. The postoperative course was uneventful and maxillofacial symmetry was obtained to the patient's satisfaction at the 6 months follow-up.

[A Case of Early Detection and Treatment Applicable to Squamous Cell Carcinoma of the Palate Detected by Oral Cancer Mass Screening in Izumo 2019].

Treatment of oral cancer is based on radical resection and reconstructive surgery. Surgery causes impairment of maxillofacial morphology and function, including chewing and eating difficulties, and dysarthria. It is necessary to restore the maxillofacial morphology and function by reconstructive surgery and use of prostheses. Therefore, early detection and treatment are required to reduce these disabilities associated with oral cancers. Here, we report a case of oral cancer that was detected early by our oral cancer mass screening program in Izumo, Japan, in 2019. A 73-year-old woman presented with a reddish ulcerative region in the palate. Cytological screening indicated positive-suspected low squamous intraepithelial neoplasia (LSIL). The patient was diagnosed as squamous cell carcinoma of the palate(cT1N0M0, StageⅠ)in our hospital. We performed radical resection of the palate tumor and immediate reconstruction using a vascularized radial forearm flap. The clinical course was good and oral function was fully restored. It is important for oral surgeons to publicize and raise awareness of oral cancer, and to continue oral cancer mass screening programs.

[Surgical Procedure for Postoperative Reconstruction of Swallowing Function in a Very Elderly Patient with Advanced Tongue Cancer].

Surgical ablation and reconstruction are the first-line treatment strategies for squamous cell carcinoma of the tongue. However, locally advanced cases can be complicated by postoperative dysphagia. Here, we report a case of advanced tongue cancer in a very elderly patient who regained good swallowing function following a reconstructive surgery using a pectoralis major musculocutaneous flap with elevation of the hyoid bone. Case: An 89-year-old man diagnosed with advanced squamous cell carcinoma of the tongue(cT4aN2bM0, cStage ⅣA)underwent tracheostomy, right modified radical neck dissection type Ⅱ, left supraomohyoid neck dissection, subtotal glossectomy, and pectoralis major musculocutaneous flap reconstruction under general anesthesia. Intraoperatively, holes were created in the lower edge of the mandible, and the hyoid bone was suspended and fixed to the mandibular border using 2-0 nylon sutures. The postoperative course was uneventful. The flap had been completely engrafted and was in a good condition. The pharyngeal stage of swallowing function was reproduced through a reconstructive surgery with suspension and fixation of the hyoid bone toward the border of the mandible. Video fluorography 6 months postoperatively showed that good swallowing function was achieved using a palatal augmentation prosthesis.

Impact of COVID-19 pandemic on the dynamic of patients with oral and maxillofacial trauma: interrupted time-series analysis.

Oral and maxillofacial trauma is influenced by various factors, including regional characteristics and social background. Due to the coronavirus disease 2019 (COVID-19) pandemic, a state of emergency was declared in Japan in March 2020. In this study, we aimed to examine the dynamics of patients with oral and maxillofacial trauma over a 12-years period using interrupted time-series (ITS) analysis. Patients were examined at the Shimane University Hospital, Maxillofacial Trauma Center from April 2012 to April 2023. In addition to general patient characteristics, data regarding the type of trauma and its treatment were obtained from 1203 patients (770 men and 433 women). Group comparisons showed significant differences in age, trauma status, method of treatment, referral source, route, and injury occasion. ITS analysis indicated significant changes in combined nasal fractures, non-invasive reduction, and sports injuries (P < 0.05), suggesting COVID-19 significantly impacted oral and maxillofacial trauma dynamics. A pandemic of an infectious disease may decrease the number of minor trauma cases but increase the number of injuries from outdoor activities, resulting in no overall change in the dynamics of the number of trauma patients. Medical systems for oral and maxillofacial trauma should be in place at all times, independent of infectious disease pandemics.

Postoperative Complications following Open Reduction and Rigid Internal Fixation of Mandibular Condylar Fracture Using the High Perimandibular Approach.

The high perimandibular approach is a feasible surgical technique for treating mandibular condylar fractures with open reduction and internal fixation, followed by fewer complications. Temporary trismus is the only postoperative complication that may occur. This study evaluated postoperative complications following open reduction and rigid internal fixation (OR-IF) of mandibular condylar fractures using the high perimandibular approach. Twenty consecutive patients undergoing OR-IF were included in this study. They included 11 male and 9 female patients, of an average age of 58.5 years, all of whom responded to a follow-up call at least 12 months after the surgery. All patients were evaluated for range of mouth opening, postoperative complications, and radiological findings. A statistical analysis of the relationship between range of mouth opening and related clinical parameters at 6 months postoperative evaluation was conducted. The fracture of the condylar neck was associated with a limited range of mouth opening and longer operation time. However, longer operation time was not associated with a limited range of mouth opening. The high perimandibular approach with OR-IF in mandibular condylar fractures is a feasible and safe technique; however, prolonged surgery and mandibular condylar neck fractures could affect the postoperative range of mouth opening.

Feasibility of Application of the Newly Developed Nano-Biomaterial, ß-TCP/PDLLA, in Maxillofacial Reconstructive Surgery: A Pilot Rat Study.

This study was performed to examine the applicability of the newly developed nano-biocomposite, ß-tricalcium phosphate (ß-TCP)/u-HA/poly-d/l-lactide (PDLLA), to bone defects in the oral and maxillofacial area. This novel nano-biocomposite showed several advantages, including biocompatibility, biodegradability, and osteoconductivity. In addition, its optimal plasticity also allowed its utilization in irregular critical bone defect reconstructive surgery. Here, three different nano-biomaterials, i.e., ß-TCP/PDLLA, ß-TCP, and PDLLA, were implanted into critical bone defects in the right lateral mandible of 10-week-old Sprague-Dawley (SD) rats as bone graft substitutes. Micro-computed tomography (Micro-CT) and immunohistochemical staining for the osteogenesis biomarkers, Runx2, osteocalcin, and the leptin receptor, were performed to investigate and compare bone regeneration between the groups. Although the micro-CT results showed the highest bone mineral density (BMD) and bone volume to total volume (BV/TV) with ß-TCP, immunohistochemical analysis indicated better osteogenesis-promoting ability of ß-TCP/PDLLA, especially at an early stage of the bone healing process. These results confirmed that the novel nano-biocomposite, ß-TCP/PDLLA, which has excellent biocompatibility, bioresorbability and bioactive/osteoconductivity, has the potential to become a next-generation biomaterial for use as a bone graft substitute in maxillofacial reconstructive surgery.

Bioactive Regeneration Potential of the Newly Developed Uncalcined/Unsintered Hydroxyapatite and Poly-l-Lactide-Co-Glycolide Biomaterial in Maxillofacial Reconstructive Surgery: An In Vivo Preliminary Study.

Uncalcined/unsintered hydroxyapatite (HA) and poly-l-lactide-co-glycolide (u-HA/PLLA/PGA) are novel bioresorbable bioactive materials with bone regeneration characteristics and have been used to treat mandibular defects in a rat model. However, the bone regenerative interaction with the periosteum, the inflammatory response, and the degradation of this material have not been examined. In this study, we used a rat mandible model to compare the above features in u-HA/PLLA/PGA and uncalcined/unsintered HA and poly-l-lactic acid (u-HA/PLLA). We divided 11 male Sprague-Dawley rats into 3- and 16-week groups. In each group, we assessed the characteristics of a u-HA/PLLA/PGA sheet covering the right mandibular angle and a u-HA/PLLA sheet covering the left mandibular angle in three rats each, and one rat was used as a sham control. The remaining three rats in the 16-week group were used for a degradation assessment and received both sheets of material as in the material assessment subgroup. At 3 and 16 weeks after surgery, the rats were sacrificed, and mandible specimens were subjected to micro-computed tomography, histological analysis, and immunohistochemical staining. The results indicated that the interaction between the periosteum and u-HA/PLLA/PGA material produced significantly more new bone regeneration with a lower inflammatory response and a faster resorption rate compared to u-HA/PLLA alone. These findings may indicate that this new biomaterial has ideal potential in treating maxillofacial defects of the midface and orbital regions.

A Narrative Review of u-HA/PLLA, a Bioactive Resorbable Reconstruction Material: Applications in Oral and Maxillofacial Surgery.

The advent of bioresorbable materials to overcome limitations and replace traditional bone-reconstruction titanium-plate systems for bone fixation, thus achieving greater efficiency and safety in medical and dental applications, has ushered in a new era in biomaterial development. Because of its bioactive osteoconductive ability and biocompatibility, the forged composite of uncalcined/unsintered hydroxyapatite and poly L-lactic acid (u-HA/PLLA) has attracted considerable interest from researchers in bone tissue engineering, as well as from clinicians, particularly for applications in maxillofacial reconstructive surgery. Thus, various in vitro studies, in vivo studies, and clinical trials have been conducted to investigate the feasibility and weaknesses of this biomaterial in oral and maxillofacial surgery. Various technical improvements have been proposed to optimize its advantages and limit its disadvantages. This narrative review presents an up-to-date, comprehensive review of u-HA/PLLA, a bioactive osteoconductive and bioresorbable bone-reconstruction and -fixation material, in the context of oral and maxillofacial surgery, notably maxillofacial trauma, orthognathic surgery, and maxillofacial reconstruction. It simultaneously introduces new trends in the development of bioresorbable materials that could used in this field. Various studies have shown the superiority of u-HA/PLLA, a third-generation bioresorbable biomaterial with high mechanical strength, biocompatibility, and bioactive osteoconductivity, compared to other bioresorbable materials. Future developments may focus on controlling its bioactivity and biodegradation rate and enhancing its mechanical strength.