Facile bioactive transformation of magnesium alloy surfaces for surgical implant applications

The market for orthopedic implant alloys has seen significant growth in recent years, and efforts to reduce the carbon footprint of medical treatment (i.e., green medicine) have prompted extensive research on biodegradable magnesium-based alloys. Magnesium alloys provide the mechanical strength and biocompatibility required of medical implants; however, they are highly prone to corrosion. In this study, Mg-9Li alloy was immersed in cell culture medium to simulate degradation in the human body, while monitoring the corresponding effects of the reaction products on cells. Variations in pH revealed the generation of hydroxyl groups, which led to cell death. At day-5 of the reaction, a coating of MgCO3 (H2O)3, HA, and α -TCP appeared on sample surfaces. The coating presented three-dimensional surface structures (at nanometer to submicron scales), anti-corrosion effects, and an altered surface micro-environment conducive to the adhesion of osteoblasts. This analysis based on bio-simulation immersion has important implications for the clinical use of Mg alloys to secure regenerated periodontal tissue

Protocol for a multicentre, prospective observational study of elective neck dissection for clinically node-negative oral tongue squamous cell carcinoma (END-TC study)

Introduction: In early-stage oral tongue squamous cell carcinoma (OTSCC), elective neck dissection (END) is recommended when occult lymph node metastasis is suspected; however, there is no unanimous consensus on the risks and benefits of END in such cases. The management of clinically node-negative (cN0) OTSCC remains controversial. This study, therefore, aimed to evaluate the efficacy of END and its impact on the quality of life (QoL) of patients with cN0 OTSCC. Methods and analysis: This is a prospective, multicentre, nonrandomised observational study. The choice of whether to perform END at the same time as resection of the primary tumour is based on institutional policy and patient preference. The primary endpoint of this study is 3-year overall survival. The secondary endpoint are 3-year disease-specific survival, 3-year relapse-free survival and the impact on patient QoL. Propensity score-matching analysis will be performed to reduce selection bias. Ethics and dissemination: This study was approved by the Clinical Research Review Board of the Nagasaki University. The protocol of this study was registered at the University Hospital Medical Information Network Clinical Trials Registry. The datasets generated during the current study will be available from the corresponding author on reasonable request. The results will be disseminated internationally, through scientific and professional conferences and in peer-reviewed medical journals

Protocol for a multicentre, prospective observational study of elective neck dissection for clinically node-negative oral tongue squamous cell carcinoma (END-TC study)

Introduction In early-stage oral tongue squamous cell carcinoma (OTSCC), elective neck dissection (END) is recommended when occult lymph node metastasis issuspected; however, there is no unanimous consensus on the risks and benefits of END in such cases. The management of clinically node-negative (cN0) OTSCCremains controversial. This study, therefore, aimed to evaluate the efficacy of END and its impact on the quality of life (QoL) of patients with cN0 OTSCC.Methods and analysis This is a prospective, multicentre, nonrandomised observational study. The choice of whether to perform END at the same time as resection of the primary tumour is based on institutional policy and patient preference. The primary endpoint of this study is 3-year overall survival. The secondary endpoints are3-year disease-specific survival, 3-year relapse-free survival and the impact on patient QoL. Propensity score-matching analysis will be performed to reduce selection bias.Ethics and dissemination This study was approved by the Clinical Research Review Board of the Nagasaki University. The protocol of this study was registered at the University Hospital Medical Information Network Clinical Trials Registry. The datasets generated during the current study will be available from the correspondingauthor on reasonable request. The results will be disseminated internationally, through scientific and professional conferences and in peer-reviewed medical journals

Peri-operative management of multiple tooth extractions in a patient with congenital hypofibrinogenemia receiving anticoagulant therapy

Congenital fibrinogen disorder is rare and is responsible for the difficulty in achieving hemostasis following surgery. A 75-year-old man was referred to our hospital for the management of gingival hemorrhage. He had a medical history of congenital hypofibrinogenemia, right internal carotid stenosis, hypertension, brain infarction, and Alzheimer's disease. A diagnosis of gingival hemorrhage due to periodontitis of the maxillary left second molar and severe periodontitis necessitating extraction in the maxillary second molars bilaterally, mandibular left second molar, and mandibular right first and third molars was made. A pre-operative hematological examination revealed a fibrinogen level of 53.7 mg/dl. Fibrinogen (3 g) was administered and reached a concentration of 92.8 mg/dl before the surgery. Several episodes of post-operative hemorrhages in the sockets were managed with local hemostatic treatment and splint adjustment. Fibrinogen levels were maintained at 72.5-92.8 mg/dl, until hemostasis was achieved. This case report illustrates the appropriate management of patients with congenital hypofibrinogenemia requiring extraction of multiple teeth

Management of the N0 Neck in Early Stage Oral Squamous Cell Carcinoma

Management of clinically node negative neck patients with oral squamous cell carcinoma (OSCC) remains controversial. Elective neck dissection (END) is used on an assumption of difficulty in diagnosing subclinical nodal metastases in the neck. This is also the case when early dissection allows better prognosis if nodal metastases actually exist. However, the disadvantage of prophylactic END is that truly N0 neck patients undergo unnecessary neck dissection and have to bear shoulder complaints and dysfunction. Our strategy has been a“ wait and see” policy for the management of the neck among patients with T1-2 oral cancer without clinical nodal metastases unless the neck was being opened for reconstruction requirements. The purpose of this study is to assess the outcome of patients who underwent trans-oral tumor excision and“ wait-and-see” policy for the N0 neck. 　A total of 94 previously untreated patients with T1-2N0 classification were investigated. Elective neck dissection (END) was carried out on 10 patients (10.6%) at the time of treatment of the primary resection with reconstruction (END group), and 84 patients were observed without neck dissection (Observation group). 　The 5-year disease specific survival rates were 90.0% for the END group and 95.9% for the observation group. The 5-year over all survival rates were 90.0% in the END group and 88.8% in the observation group. In the observation group of 84 patients, 16 patients (19.0%) had delayed metastasis in the neck subsequently. 15 patients underwent salvage neck dissection. The salvage rate was 86.6% (13/15 patients). 　The treatment strategy “wait and see” policy for T1-2N0 OSCC resulted in a good outcome at our institution. Unnecessary neck dissection can be avoided for the truly N0 patients

Therapeutic strategies for etiologies in the oral and maxillofacial regions

In this paper we describe our strategies for treatment of oral cancer, jaw deformity, and odontogenic tumors. Details of the strategy for cleft palate is introduced in a separate report, by Professor Mikoya. Newly applied strategies for patients with post-surgical swallowing dysfunction and dentoalveolar surgery are also introduced. Oral cancer, jaw deformity, cleft, and odontogenic tumors are the main etiologies in the oral and maxillofacial region. Early stages of oral cancer (StageI and StageII) are mainly treated with surgery or radiotherapy alone, and the 5-year survival rate is 80 to 90%. With advanced oral cancer (StageIII and StageIV) a combination of chemotherapy and radiotherapy with or without surgery is the norm, but the 5-year survival rate is below 50% overall. Therefore, there is a need for an effective combination of therapies for advanced oral squamous cell carcinomas. The treatment goal for jaw deformities is to achieve a functional and desirable occlusion. To achieve desirable occlusion, treatment by the team approach is introduced, it includes oral and maxillofacial surgeons, orthodontists, and prosthodontists. A unique method, termed the “Dredging Method” is used in the treatment strategies of odontogenic tumors. The method was introduced to remove all of the tumor and restore the form and function of the jaw through bone generation. The Dredging Method involves four steps: Deflation, Enucleation, Dredging, and Follow up.　Tooth autotransplantation in our department stands out in comparison with other facilities in the field of dentoalveolar surgery. The annual number of cases exceeds 150, and up to December of 2015 the total number of cases reached 1,100. The 5-year survival rate for cases with transplanted third molars to the molar region is 86%. Post-surgical swallowing dysfunction is strongly dependent on the extent of the surgery and type of reconstruction. Here, post-surgical swallowing dysfunction can be accurately predicted prior to the surgery, and to develop plans for individual rehabilitation programs to overcome post-surgical swallowing dysfunction is crucial

Recovery from Postsurgical Swallowing Dysfunction in Patients With Oral Cancer

Patients and Methods: The swallowing function was assessed in 25 patients (18 males and 7 females) with oral cancer. The swallowing function was assessed preoperatively and 1, 6, and 12 months and in some cases more than 24 months after surgery. Assessment of the swallowing function consisted of videofluoroscopic evaluation (oropharyngeal swallow efficiency; OPSE) and details of the method of nutrition, diet level, nutritional condition, and occurrence of pneumonia. Results: Postsurgically, OPSE did not recover to the preoperative level more than 12 months after surgery. Twenty-one patients (84%) had full oral intake and only 3 patients (12%) showed poorer nutritional conditions compared with the presurgery state. Aspiration pneumonia did not occur more than 12 months after surgery. Conclusions: The patients in the present study showed stable medical status and functional swallowing at the final evaluation despite insufficient recovery of OPSE revealed by videofluoroscopic evaluation

Long-Term Changes in Bone Height After Mandibular Reconstruction Using a Free Fibula Graft in an Elderly Population

Purpose: This study evaluated short-term and long-term changes in bone height after mandibular reconstruction using an osteotomized fibula graft, with the aim of identifying factors associated with atrophy of the graft in an elderly population. Patients and Methods: This retrospective study involved patients who underwent mandibular reconstruction using a free vascularized fibula graft from 2005 through 2015 and had at least 12 months of follow-up. Postoperative panoramic radiographs were used to measure bone height at standardized locations on each segment of the graft at 1 year postoperatively and at later follow-up. Results: The sample was composed of 30 patients (15 men, 15 women; mean age, 62.6 years; age range, 50 to 80 years). According to the HCL classification (H, hemimandibular segment including the condyle; C, central segment including both mandibular canine teeth; L, lateral segment without the condyle), mandibular defect types were L (n = 19), LC (n = 7), LCL (n = 3), and H (n = 1). There were 0 to 3 segmental osteotomies with the fibula graft. None of the patients received an osseointegrated dental implant during a mean follow-up of 4.0 years (range, 1.5 to 9.7 yr). All patients underwent reconstruction of the mandibular body, 10 of whom also underwent reconstruction of the mandibular ramus. Atrophy of the fibula graft was observed in 9.9 and 15.0% of the body segment and 5.9 and 6.6% of the ramal segment at 1 year postoperatively and at later follow up, respectively. Graft hypertrophy occurred in the ramal segment in 2 patients. Multivariate analysis showed a significantly higher rate of graft atrophy in women than in men at later follow-up (P = .033). Conclusions: Fibula grafts showed long-term stability, and in 2 cases even a gain in bone height, in this elderly population. Female gender was identified as a risk factor for atrophy of the fibula bone graft in the body segment of the reconstructed mandible. (c) 2017 American Association of Oral and Maxillofacial Surgeon

Does Swallowing Function Recover in the Long Term in Patients With Surgically Treated Tongue Carcinomas?

Purpose: The present study aims to measure the post-surgical swallowing function in patients five years after operative treatment of tongue carcinoma. Patients and Methods: Using a retrospective cohort study design, the investigators enrolled post-surgical patients treated for tongue carcinomas in Hokkaido University Hospital. The primary outcome variable was the Oropharyngeal Swallow Efficiency (OPSE) determined by videofluoroscopic evaluation and the OPSE at present was compared with that at discharge. Other variables included present nutritional status (Body Mass Index: BMI, Serum Albumin), dietary intake, self-rating of the present swallowing function, and occurrence of pneumonia. Statistical analysis used the paired t-test and Spearman's rank correlation. Results: The swallowing function was assessed in 20 patients (11 males and 9 females) subjected to surgical treatment of tongue carcinomas; the median age was 70 years (range 56-90 years) at the present evaluation. The mean values of the liquid OPSE and paste OPSE at present were 26.6±21.2 and 21.9±22.5, respectively. The mean values for BMI and serum albumin at present were 22.2±3.4 and 4.5±0.3g/dl respectively. All patients had a full oral intake of foods, with a mean self-rated value of 6.4±2.5, an acceptable value as evaluated by the patients. Pneumonia requiring hospitalization had not occurred in these patients. Conclusions: Long-term follow-up of patients following operative treatment of tongue carcinomas demonstrate acceptable levels of oral function and nutritional status despite objective measures of poor swallowing efficiency assessed using a videofluoroscopy

Application of "Dredging Method" for the patients with odontogenic keratocyst.

When conservative treatment such as enucleation is applied, odontogenic keratocyst (OKC) is a well-known jaw lesion with a high recurrence rate. Other treatment modalities aimed at preventing recurrence have been used for managing OKCs. In our institute, an alternative conservative approach, known as the dredging method, is applied in OKC treatment. This paper describes and reports the characteristics and outcomes of conservative treatments involving the dredging method and enucleation in the management of patients with OKC. Seventy-four patients with OKC or keratocystic odontogenic tumor (KCOT) presented to Oral and Maxillofacial Surgery at Hokkaido University Hospital between 1983 and 2017. They were treated and followed for more than 12 months. The patients’ median age was 40 years (range 7‒72 years) and the median longitudinal diameter of the lesion was 30 mm (range 7‒128 mm). A total of 14 cysts (18.9%) were multilocular, as determined via radiographic evaluation. The surgical intervention consisted of enucleation alone in 17 cases (22.3%), deflation followed by enucleation in seven cases (9.5 %), and the dredging method in 50 cases. Statistical significance associated with the size ( P = 0.01) and locularity ( P = 0.02) of the lesions was found between the cases treated with enucleation versus the dredging method. The median duration of follow-up was 40 months (range 12 to 405 months). Recurrence occurred in 9 of 74 cases (12.2%), including 2 of 17 cases (11.8%) treated with enucleation and 7 of 57 cases (12.3 %) treated wit h the dredging method. The recurrence period ranged from 12 to 131 months. All recurrence cases were managed by enucleation. There was no correlation between recurrence and patient sex or age, lesion size or locularity, the presence of a daughter cyst, or surgical approach. These results suggest that the dredging method is a s uccessful conservative treatment option for large, multilocular OKCs. Long-term regular follow-up is essential to identify and manage recurrent cases