Identifying genetic variants underlying medication-induced osteonecrosis of the jaw in cancer and osteoporosis: a case control study.

BACKGROUND: Bisphosphonate-induced osteonecrosis of the jaw (BRONJ) presents with a typical pattern of jaw necrosis in patients who have been prescribed bisphosphonates (BPs) and other antiangiogenetic drugs to treat osteoporosis or bone-related complications of cancer. METHODS: This study divided 38 patients with BRONJ into two groups according to the prescribing causes: cancer (n = 13) and osteoporosis (n = 25), and underwent whole exome sequencing and compared them with normal controls (n = 90). To identify candidate genes and variants, we conducted three analyses: a traditional genetic model, gene-wise variant score burden, and rare-variant analysis methods. RESULTS: The stop-gain mutation (rs117889746) of the PZP gene in the BRONJ cancer group was significantly identified in the additive trend model analysis. In the cancer group, ARIDS, HEBP1, LTBP1, and PLVAP were identified as candidate genes. In the osteoporosis group, VEGFA, DFFA, and FAM193A genes showed a significant association. No significant genes were identified in the rare-variant analysis pipeline. Biologically accountable functions related to BRONJ occurrence-angiogenesis-related signaling (VEGFA and PLVAP genes), TGF-ß signaling (LTBP1 and PZP genes), heme toxicity (HEBP1) and osteoblast maturation (ARIDS)-were shown in candidate genes. CONCLUSION: This study showed that the candidate causative genes contributing to the development of BRONJ differ according to the BP dose and background disease.

Mirror Image Based Three-Dimensional Virtual Surgical Planning and Three-Dimensional Printing Guide System for the Reconstruction of Wide Maxilla Defect Using the Deep Circumflex Iliac Artery Free Flap.

A patient was diagnosed with squamous cell carcinoma of the maxillary sinus and consequently underwent a unilateral total maxillectomy and reconstruction using an anterolateral thigh (ALT) free flap. Soft tissue transplantation without a bone graft at the large maxillary defect site caused a midfacial collapse, which worsened, especially after radiotherapy. The 3-dimensional positioning of the composite flap for wide maxillary reconstruction is aesthetically important. To achieve ideal symmetry and aesthetics, a mirror image was created using the normal contralateral side. Through computer simulation, the function and symmetry of the virtually reconstructed maxilla was evaluated, and the surgical guide was made using a 3D printing system. Based on the prepared surgical guide, a deep circumflex iliac artery (DCIA) free flap was harvested, and its implementation in the reconstruction ultimately led to satisfactory results. Utilization of mirror image based virtual surgical planning and a 3D printing guide is a significantly effective method for maxilla reconstruction with DCIA flaps.

Reconstruction of Thin and Pliable Oral Mucosa After Wide Excision of Oral Cancer Using a Trimmed Anterolateral Thigh Free Flap as an Adipofascial Flap.

A 21-year-old female patient underwent wide excision of the buccal mucosa and tongue as well as selective neck dissection due to squamous cell carcinoma on the left side of the tongue. She had a severe limitation in opening her mouth, owing to fibrosis of the mucosa and scar contracture after adjuvant radiation therapy. Reconstruction of the oral mucosa and tongue defect was performed after removal of the scar to improve mouth opening. An anterolateral thigh (ALT) flap was used, trimmed to an adipofascial flap for the reconstruction of the thin and pliable oral mucosa and tongue. The maximum mouth opening improved to 40 mm intraoperatively and was 30 mm after surgery. The adipofascial ALT flap had excellent viability and presented neomucosa after secondary healing. An adipofascial flap obtained by trimming an ALT flap could be a reliable option for the reconstruction of thin and pliable oral mucosa after wide excision of oral cancer.

Novel PTCH1 Gene Mutation in Nevoid Basal Cell Carcinoma Syndrome.

The purpose of this study was to report clinical characteristics, surgical results, and new PTCH1 gene mutations in nevoid basal cell carcinoma syndrome (NBCCS). Five patients were referred to the Department of Oral and Maxillofacial Surgery from local dental clinics between 2006 and 2016 to treat multiple keratocystic odontogenic tumors (KOTs). The cystic lesions were enucleated and peripheral ostectomy was performed to obtain safety margin. Recurrence and/or de novo development of KOT were assessed. Gene analysis using peripheral blood was performed in all patients to identify the mutation of PTCH1 gene. Three patients showed familial history of first-degree relatives. Of the major criteria, all patients presented KOT but only 1 patient had basal cell carcinoma. Of the minor criteria, 4 of the 5 patients presented macrocephaly and hypertelorism. During follow-up periods, all patients showed recurrence and/or de novo development of KOT in the jaw bone. Mutation analysis of PTCH1 gene showed 3 frameshifts (c.817_818ins(T), c.1226_1227ins(A), and c.2748del(C)), 1 splicing (c.1504-2A>T), and 1 missense (c.385T>C) mutation. Mutations were found in exon 1, 6, 9, 17, and intron 10. Regular follow-up is necessary because recurrence rate of KOT was very high. To help early diagnosis, it is essential to routinely perform genetic testing to detect PTCH1 gene mutations among patients with NBCCS.

Endoscopic removal of an aspirated healing abutment and screwdriver under conscious sedation.

PURPOSE: Aspiration of foreign bodies during dental treatment is a medical emergency that requires prompt removal. In this study, aspiration of screwdriver and healing abutment is reported with literature review. MATERIALS AND METHODS: A 26-year-old male patient was referred from a local dental clinic with the suspicion of ingestion of a screwdriver and healing abutment during the second-stage surgery. The patient reported symptoms including dyspnea, cough, and foreign body sensation. On the chest radiograph, a radiopaque foreign body resembling the screwdriver and healing abutment was observed at the right mid lung. RESULTS: Bronchoscopic examination using flexible cable was performed under conscious sedation, and microforceps were used to remove the instruments. Aspirated screwdriver and healing abutment were removed safely under intravenous sedation. The patient did not have any symptoms associated with lung aspiration after removal of the foreign body during follow-up periods. CONCLUSION: Bronchoscopic removal is the most recommended procedure for removal of the aspirated foreign body. This can be performed under conscious sedation. Precautions, such as tethering the screwdriver, are recommended during implant procedures.

Prognostic factors of oral squamous cell carcinoma: the importance of recurrence and pTNM stage.

BACKGROUND: Oral squamous cell carcinoma has a poor prognosis. Therefore, prognostic factors are important to increase the survival rate. This study assessed the survival rate and the prognostic factors for survival of patients with oral squamous cell carcinoma. METHOD: This study included 168 patients who underwent surgery for oral squamous cell carcinoma between January 2006 and December 2021. The survival rate was analyzed with overall survival and disease-specific survival. The patient's age, sex, pTNM stage, primary sites (lip, tongue, mouth of floor, mandibular gingiva, maxillary gingiva, mandibular vestibule, maxillary vestibule, retromolar trigone, palate, buccal mucosa, primary intra-osseous site), smoking and alcohol drinking habits, depth of invasion, perineural and lymphovascular invasion, cell differentiation, and postoperative radiotherapy were evaluated to analyze risk factors. Kaplan-Meier methods were used to estimate the survival rates. Cox regression methods were used to investigate the main independent predictors of survival in univariable and multivariable analysis. RESULTS: Sixty-eight patients died of oral squamous cell carcinoma during follow-up periods. Their overall survival for 5 years was 51.2%, and the disease-specific survival was 59.2%. In univariable analysis, seven factors which are neck metastasis, depth of invasion, cell differentiation, lymphovascular invasion, postoperative radiotherapy, pTNM stage, and recurrence were significantly associated with survival. In multivariable analysis, pTNM stage and recurrence were significantly associated with survival. CONCLUSION: In patients with oral squamous cell carcinoma, pTNM stage and recurrence were significant prognostic factors. Neck metastasis, depth of invasion, cell differentiation, lymphovascular invasion, and postoperative radiotherapy were also prognostic factors. These factors serve as markers for obtaining prognosis information in oral squamous cell carcinoma.

Identifying factors related to delayed neck metastasis after surgical treatment in patients with oral squamous cell carcinoma.

BACKGROUND: General treatment of oral squamous cell carcinoma (OSCC) is surgical treatment with or without neck dissection. Although the incidence of delayed neck metastasis is rare, it may occur after the surgery and is known to be the most important factor in the prognosis. The purpose of is study is to evaluate the clinical and histopathological factors associated with delayed neck metastasis case among patients. METHODS: A total of 195 patients who underwent surgical treatment for OSCC from 2016 to 2022 were investigated. Among them, delayed neck metastasis (DNM) was analyzed. The criterion for delayed neck metastasis was a newly developed neck lesion after the primary operation without neck dissection in cN0 necks. To identify the correlation between prognostic factors and the incidence of delayed neck metastasis, χ2 analysis with phi correlation and Cramer's V test was performed. Cumulative survival rates (CRS) were compared between the groups with the incidence of DNM and without DNM. Also, the log rank test for CSR and Cox proportional hazard model was analyzed to estimate the significance of the CSR and confirm the correlations between prognostic factors and DNM. RESULT: Among 195 patients, 14 were discovered to have DNM. The primary tumor locations were the tongue (n = 5), floor of the mouth (n = 2), mandibular gingiva (n = 1), maxillary gingiva (n = 4), retromolartrigone (n = 1), and buccal mucosa (n = 2) each. The cases consisted of TNM stage I (n = 1), stage II (n = 3), stage III (n = 3), and stage IV (n = 8), respectively. The result of the χ2 analysis identified a correlation between positive neck (p = 0.01), depth of invasion (p = 0.09), radiation therapy (p = 0.003), and DNM. Groups without DNM showed better prognosis compared to groups with DNM. Regarding positive neck, depth of invasion, and radiation therapy, only depth of invasion showed significance in CSR analysis. CONCLUSION: DNM after surgical treatment of OSCC is a rare event, and few were found in a review of the literature. Also, many prognostic factors have been suggested but controversial. However, in our study, some prognostic factors have been identified to have a significant correlation with the incidence of DNM, and analysis of such factors provides important information predicting neck metastasis and the prognosis.

Radiological features of Stafne mandibular bone cavity in panoramic image and cone beam computed tomography.

BACKGROUND: Stafne mandibular bone cavity (SMBC) is an asymptomatic radiolucent lesion observed in the mandible on X-ray images, with well-defined borders. This lesion does not require treatment, and size changes are very rare. The purpose of this article is to summarize the radiological and clinical features of SMBC, aiming to prevent misinterpretation of this benign lesion as other pathologies and aid in differential diagnosis within the field of dental practice. METHODS: A total of 32 patients who visited our hospital and were radiologically diagnosed with SMBC based on cone-beam computed tomography (CBCT) and panoramic images between 2005 and 2021 were included in this study. Among them, surgical intervention was performed in one case. Gender and age distribution of the patients, radiographic location and size of the lesion, relationship with the mandibular canal in CBCT, presence of cortical bone erosion in the mandibular lingual area in panoramic images, and the amount of residual cortical bone on the affected side in CBCT were investigated. RESULT: Patients were 26 men (81.3%) and 6 women, with a mean age of 54.3 years. The average horizontal and vertical length was 16.6 mm and 10.6 mm. Out of a total of 32 cases, 29 cases were found in the posterior region of the mandibular body, while 3 cases were in the angle of the mandible. Lesions located below the mandibular canal were observed in 29 cases, while lesions involving the mandibular canal were present in 3 cases. Erosion of the mandibular lingual cortical bone was observed in 11 cases (34.4%), while 21 cases (65.6%) showed no erosion on panoramic images. Among the total of 14 cases (43.8%) where the cortical bone on the affected side was invaded, the average residual cortical bone thickness was 1.1 mm. CONCLUSION: SMBC is a benign lesion primarily found in the mandibular angle and posterior body of the mandible. In most cases, treatment is not necessary, and differentiation from other lesions can be achieved by understanding its clinical characteristics and features on panoramic radiographs and CBCT.

Customized three-dimensional printed ceramic bone grafts for osseous defects: a prospective randomized study.

Ridge resorption can result in insufficient bone volume for implant surgery, necessitating bone substitutes to restore the resorption area. Recent advances in computer-aided design and manufacturing enable the use of alloplastic bone graft materials with customizable compositions or shapes. This randomized study evaluated the clinical effectiveness of a customized three-dimensional (3D) printed alloplastic bone material. Sixty patients requiring guided bone regeneration for implant installation following tooth extraction due to alveolar bone resorption were recruited at two institutions. The participants were randomly allocated to either a group that received 3D-printed patient-customized bone graft material or a group that received conventional block bone graft material. Implant installation with bone harvesting was performed approximately 5 months after bone grafting. Histological and radiological assessments of the harvested bone area were performed. The experimental group had a significantly higher percent bone volume and a smaller tissue surface than the control group. Bone volume, bone surface, bone surface/volume ratio, bone surface density (bone surface/total volume), and bone mineral density did not differ significantly between groups. Patient-customized bone graft materials offer convenience and reduce patient discomfort. The findings suggest 3D-printed patient-customized bone graft materials could be used as an alternative for simpler bone grafting procedures.

Immediate free iliac bone graft after nonsegmental mandibular resection and delayed implant placement: a case series.

BACKGROUND: Resection of mandibular tumors without proper reconstruction may lead to unfavorable esthetic and function results. The purpose of this case series was to describe clinical results and a technique to prevent tissue loss using nonvascular iliac grafts immediately following tumor resection and long-term stability of the implants. MATERIALS AND METHODS: Three female patients presented with oral neoplasms (2 ameloblastoma and 1 ossifying fibroma). The mandibular reconstruction was performed with nonvascularized iliac grafts simultaneous with tumor removal. Subsequently, 10 dental implants were placed 6 to 9 months after reconstruction and restored. Survival and success of the implants were evaluated. RESULTS: Marginal mandibulectomy in 1 patient and buccal bone resection in 2 patients was performed; the resection sites were reconstructed with an immediate nonvascularized iliac graft. All implants survived and were successful during follow-up periods between 44 and 105 months. Mean marginal bone loss of 10 implants was 0.09 mm. CONCLUSIONS: Immediate reconstruction with nonvascularized iliac grafts following tumor resection may be a viable treatment option for nonsegmental inlay osseous defects. In these case series, the resorption of the iliac bone was minimal after 6 to 9 months consolidation periods.

Associated systemic diseases and etiologies of medication-related osteonecrosis of the jaw: a retrospective study of 265 surgical cases.

BACKGROUND: Medication-related osteonecrosis of the jaw (MRONJ) is one of the complications caused by various drugs. As there are increasing reports of MRONJ, it is important to diagnose and identify patients who have the potential risk of the disease. The aim of this study was to analyze the systemic diseases, etiology, and treatment results of MRONJ. MATERIAL AND METHODS: A total of 265 MRONJ operations were reviewed retrospectively. This study included patients who were diagnosed as MRONJ and those who also received surgery, ranging from simple extraction to reconstruction with free flaps, from 2009 to 2021. Each patient's systemic disease and eitology and basic demographic information was taken into consideration. RESULTS: The most common diseases related were osteoporosis (n = 127), breast cancer (n = 77), multiple myeloma (n = 27), prostate cancer (n = 26), and etc. (n = 12). The related causes of MRONJ were extraction (n = 138), implants (n = 40), and irritations by prosthesis (n = 29); however, 55 cases were occurred spontaneously. Out of 265 patients, 214 were women while 51 were men. The average age when the surgery took place was 67.7 and 69.8 years for male and female patients, respectively. Saucerization and sequestrectomy (n = 252) was the most common surgical treatment, followed by mandibulectomy (n = 12) and partial maxillectomy (n = 1). While 4 cases occurred in both jaws, 168 cases were in the mandible and 93 cases were in the maxilla. CONCLUSION: Nearly 50 % of the MRONJ patients had osteoporosis and the other patients who received bone targeting agents parentral had bone metastasis of various cancers. Extraction is the most common related event for MRONJ.

Lesch-Nyhan syndrome: a case report.

Lesch-Nyhan syndrome (LNS) is a rare X-linked recessive disorder caused by a mutation in the hypoxanthine phosphoribosyltransferase 1 (HPRT1) gene. This syndrome is characterized by excessive production of uric acid, mental retardation, self-mutilation, choreoathetosis, and spasticity. The most distinctive symptom is compulsive self-mutilation. For patients with LNS, different methods have been tried to reduce self-biting behaviors including restraints, behavioral treatment, medications, deep brain stimulation, tooth extraction and botulinum toxin A injection. In this report, we present a case of LNS undergoing cheiloplasty due to self-mutilation and tooth extraction of the left deciduous maxillary canine.

Features of Odontogenic Sinusitis Associated With Dental Implants.

OBJECTIVES: With the increase in dental implants for tooth loss, odontogenic sinusitis following maxillary dental implants is frequently encountered in otorhinolaryngology practice. The authors aimed to reveal the association between implant extrusion into maxillary sinus, along with implant-related complications in patients diagnosed with implant-related odontogenic sinusitis (IR-ODS). STUDY DESIGN: Case-control study. METHODS: This study enrolled 60 patients who received functional endoscopic sinus surgery due to IR-ODS. The preoperative sinus computed tomography was retrospectively reviewed. Among the 120 maxillary sinuses of the 60 patients, 68 sides were diagnosed with IR-ODS sides, whereas 27 sides showed no clinical or radiological evidence of this condition after the implant insertion and were defined as the control sides. Statistical analysis between these two groups was conducted, in addition to odds ratio (OR) calculations for associations with IR-ODS. RESULTS: The mean age of the IR-ODS subjects was 59.5 ± 19.1, with a male to female ratio of 32/28 (53.3%/46.7%). Implants extruding by more than 4 mm into the maxillary sinus, peri-implantitis, bone graft disruption-extrusion were associated with a significantly higher incidence in the IR-ODS (p = 0.035, p = 0.003, p = 0.011, respectively). The IR-ODS sides showed an adjusted-OR (95% confidence interval) of 27.4 (2.7-276.5) for extrusion length >4 mm, 11.8 (3.0-46.5) for peri-implantitis, and 34.1 (3.3-347.8) for bone graft disruption (p = 0.005, p < 0.001, and p = 0.003, respectively). CONCLUSION: Maxillary dental implants extruding more than 4 mm into the maxillary sinus, peri-implantitis, and disrupted-extruded bone grafts show significant association with IR-ODS. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:237-243, 2023.

Clinical Practice Guidelines for Oropharyngeal Dysphagia.

OBJECTIVE: Dysphagia is a common clinical condition characterized by difficulty in swallowing. It is sub-classified into oropharyngeal dysphagia, which refers to problems in the mouth and pharynx, and esophageal dysphagia, which refers to problems in the esophageal body and esophagogastric junction. Dysphagia can have a significant negative impact one's physical health and quality of life as its severity increases. Therefore, proper assessment and management of dysphagia are critical for improving swallowing function and preventing complications. Thus a guideline was developed to provide evidence-based recommendations for assessment and management in patients with dysphagia. METHODS: Nineteen key questions on dysphagia were developed. These questions dealt with various aspects of problems related to dysphagia, including assessment, management, and complications. A literature search for relevant articles was conducted using Pubmed, Embase, the Cochrane Library, and one domestic database of KoreaMed, until April 2021. The level of evidence and recommendation grade were established according to the Grading of Recommendation Assessment, Development and Evaluation methodology. RESULTS: Early screening and assessment of videofluoroscopic swallowing were recommended for assessing the presence of dysphagia. Therapeutic methods, such as tongue and pharyngeal muscle strengthening exercises and neuromuscular electrical stimulation with swallowing therapy, were effective in improving swallowing function and quality of life in patients with dysphagia. Nutritional intervention and an oral care program were also recommended. CONCLUSION: This guideline presents recommendations for the assessment and management of patients with oropharyngeal dysphagia, including rehabilitative strategies.

Midfacial degloving approach for resectioning and reconstruction of extensive maxillary fibrous dysplasia.

OBJECTIVE: The traditional unilateral or bilateral buccogingival or bicoronal approach often seems to impose limitations on achieving complete resection and reconstruction of the extensive midfacial fibrous dysplasia. Therefore, we hypothesized that the midfacial degloving approach could be used for the correction of maxillary fibrous dysplasia, which has been primarily used for paranasal sinus lesions or nasopharyngeal tumor. METHODS: The study involved 5 maxillofacial fibrous dysplasia patients who underwent a midfacial degloving surgical procedure. There were 4 male patients and 1 female patient with a mean age of 16.8 years. The average, mean follow-up duration was 17.8 months. A wide, subperiosteal dissection was made along the anterior wall of the maxilla and pyriform aperture over the level of the infraorbital foramen. A bilateral, circumferential, nasal vestibular incision and dissection allowed for bilateral degloving of the middle third of the face over the infraorbital rim. Then total or subtotal resection, followed by reconstruction using an iliac bone graft, was performed. RESULTS: The midface, degloving approach provided visualization of the medial maxillary wall, the pterygoid junction, nasofrontal suture, infraorbital rim, and laterally to the temporal process of the zygoma. Subtotal or total resection of the lesions and reconstruction with bone grafts was possible in all 5 patients, and there were no complications. There was also no visible facial scarring and all patients expressed satisfaction with the cosmetic outcome. CONCLUSIONS: The midfacial, degloving approach was found to be safe and effective for maxillofacial fibrous dysplasia, and nearly total resection was possible. This approach allows for a wider dissection and resection compared with the traditional buccogingival approaches, and there was no visible facial scarring.

Subapical osteotomy to correct dental implant malpositioning and vertical ridge deficiency: a clinical report.

This clinical report describes a subapical osteotomy to correct vertical ridge deficiency and malpositioned maxillary anterior implants. A 37-year-old woman with a noncontributory medical history presented with the chief complaint of an unesthetic implant-supported prosthesis. The maxillary left central and lateral incisors were restored with metal ceramic restorations. Gingiva-colored porcelain was fabricated to compensate for severe vertical and horizontal soft tissue deficiency. The patient was dissatisfied with the esthetics associated with the restorations and soft tissues since she presented with a high smile line and gingival display. Under general anesthesia, a subapical osteotomy was performed. The implant and ridge segment was coronally repositioned to correct the ridge deficiency. The surgical procedure and postoperative healing were uneventful. The surgical outcome was stable for a follow-up period of 3 years. The subapical osteotomy provided a satisfactory clinical outcome in managing a severely deficient residual ridge and malpositioned maxillary anterior implants as an alternative treatment to other surgical approaches.

The effect of FK506 (tacrolimus) loaded with collagen membrane and fibrin glue on promotion of nerve regeneration in a rat sciatic nerve traction injury model.

BACKGROUND: Peripheral nerve injury is one of the most common injuries that might occur in oral and maxillofacial surgery. The purpose of this study was to determine the effect of FK506 loaded with collagen membrane and fibrin glue on the promotion of nerve regeneration after traction nerve injury in a rat model. METHODS: Thirty male Sprague-Dawley rats were divided into three groups: group A (n = 10), a sham group whose sciatic nerve was exposed without any injury; and groups B (n = 10) and C (n = 10), which underwent traction nerve injury using 200 g of traction force for 1 min. The injured nerve in group C was covered with a collagen membrane soaked with FK506 (0.5 mg/0.1 mL) and fibrin glue. Functional analysis and microscopic evaluation were performed at 2 and 4 weeks after injury. RESULTS: The sciatic function index was - 5.78 ± 3.07 for group A, - 20.69 ± 5.22 for group B, and - 12.01 ± 4.20 for group C at 2 weeks after injury. However, at 4 weeks, the sciatic function index was - 5.58 ± 2.45 for group A, - 19.69 ± 4.81 for group B, and - 11.95 ± 1.94 for group C. In both periods, statistically significant differences were found among the groups (p<0.017). Histomorphometric evaluation revealed improved nerve regeneration in group C compared to that in group B. However, no statistical differences in axonal density were found among the three groups (p < 0.017). CONCLUSION: Localized FK506 with collagen membrane and fibrin glue could promote axonal regeneration in a rat model of traction nerve injury.

Functional and electron-microscopic changes after differential traction injury in the sciatic nerve of a rat.

BACKGROUND: During maxillofacial trauma or oral cancer surgery, peripheral nerve might be damaged by traction injury. The purpose of this study was to evaluate functional and histomorphometric changes after traction nerve injury in the sciatic nerve of a rat model. METHODS: A total of 24 Sprague-Dawley rats were equally divided into three groups: unstretched (sham/control, group A), stretched with 0.7N (group B) and 1.5N (group C). Traction injury was performed for 10 min in B and C groups. Functional recovery of the sciatic nerve was evaluated by walking track analysis, toe spread test, and pinprick test 2 weeks after injury. The weight of gastrocnemius muscles of both sides was measured to evaluate weight ratio (ipsilateral/contralateral). Total number of axons, axon fiber size, myelin thickness, G-ratio, axon number/mm2, diameter of fiber, changes of longitudinal width, and formation of the edema and hematoma were evaluated by transmission electron microscopy. RESULTS: The sciatic function indexes were -11.48±4.0, -15.11±14.84, and -49.12±35.42 for groups A, B, and C, respectively. Pinprick test showed 3.0, 2.86±0.38, and 1.38±0.52 for A, B, and group C. Muscle weight ratios were 0.98±0.13 for group A, 0.70±0.10 for group B, and 0.54±0.05 for group C. There were significant differences in toe spread test, pinprick test, and muscle weight ratio between control group and experimental group (p<0.001). In the experimental group, fiber number, fiber size, G-ratio, fiber number/mm2, myelin thickness, diameter of fiber, and longitudinal width were decreased with statistical significance. CONCLUSION: The present study demonstrated that the nerve traction injury in the rat sciatic nerve damaged the motor and sensory function and axonal integrity. The amount of functional nerve damage was proportional to the amount of traction power and dependent on the initial tensile strengths (0.7N and 1.5N).

Prognosis of hepatocellular carcinoma metastasizing to the oral cavity.

BACKGROUND: Oral metastasis by hepatocellular carcinoma (OMHCC) is extremely rare, and the prognosis had been reported quite poor due to simultaneous multiple organ metastases. In this study, we report clinical features and survival of 10 new cases of OMHCC and suggest the criteria for palliative surgery. METHODS: A retrospective clinical study including 10 new cases of oral OMHCC between 2006 and 2016 was performed. Clinical features and survival analysis were examined. The recorded variables were age, sex, site of oral metastases, size of oral tumor (largest diameter), and survival after oral histopathologic diagnosis. RESULTS: There was male (n=8) predilection of OMHCC. The mean survival time was 16.9 months. Patient age ranged from 40 to 71 years (mean 56.5). Eight mandibular and two maxillary lesions were found. One patient showed simultaneously the maxilla and the oral tongue involvement. The most often encountered symptoms were swelling (80%) followed by pain (60%), numbness (60%), bleeding (10%), and tooth mobility (10%). Four patients underwent operation due to spontaneous bleeding and swelling of the cancer. Overall (from onset of hepatocellular carcinoma) and truncated survival (from onset of OMHCC) were 71.9 and 13.1 months respectively. CONCLUSION: The prognosis of OMHCC was quite poor. Oral and jaw bone examination should be included in patients with multiple metastasis of HCC. Palliative surgery might be performed in patients who reported spontaneous bleeding, severe pain, and oral dysphasia due to tumor enlargement.

Microvascular reconstruction for maxillofacial defects: a retrospective analysis of outcomes and complications in 121 consecutive cases.

BACKGROUND: Microvascular reconstruction is the treatment of choice after oral cancer ablation surgery. There are few published studies of free flap survival among Korean populations. This study aimed to determine the survival rate after 121 consecutive cases of maxillofacial microvascular reconstruction and to analyze the complications associated with microsurgery. METHODS: This study included consecutive patients who underwent microsurgical reconstruction with free flaps, from January 2006 through September 2019, performed by a single surgeon at the oral and maxillofacial surgery department of a tertiary medical center. A total of 121 cases were reviewed retrospectively. The flap survival rate, flap type, radiotherapy history, complications, and treatment results were analyzed. RESULTS: Four different flap types were used for microvascular reconstruction: radial forearm (n = 65), fibula (n = 34), latissimus dorsi (n = 21), and serratus anterior muscle with rib bone free flap (n = 1). Total necrosis of the flap was found in four cases (two latissimus dorsi flaps and two fibular flaps). The free flap survival rate was 97.5%. Nineteen patients received radiotherapy before surgery, and none of them experienced flap failure. The mean operation time was 334 ± 83.1 min, and the mean ischemic time was 48.9 ± 12.7 min. CONCLUSIONS: The success rate was reliable and comparable with previous studies. The success rate was not affected by radiation therapy. Free flaps can be safely used even after radiation treatment.