PubMed Health⌕ Search

Biomedical subjects

Tateyuki Iizuka

Publications and source records attributed to Tateyuki Iizuka.

At least 19 recordsLinked to original sources
PubMed2006

Occupational maxillofacial fractures: a 3-year survey in central Switzerland.

PURPOSE: The aim of this study was to determine occupational facial fractures in central Switzerland. Concomitant injuries were also studied. MATERIALS AND METHODS: The Department of Cranio-Maxillofacial Surgery at the University Hospital in Berne provides a 24-hour maxillofacial trauma service for its population (1.6 million). The present study was comprised of 42 patients (8.4% of treated maxillofacial injuries) with occupational maxillofacial fractures registered at this unit between 2000 and 2002. Information on the topic of occupation, the cause of the accidents, and the topographic location of the fractures was analyzed. RESULTS: The mean age of the patients was 44.4 years, with a male to female ratio of 41:1. Sixty-nine percent of the injuries occurred in farm and forestry workers and in construction laborers during the summertime (33%). Workers in these occupations carried a 127-fold (farm and forestry workers) and a 44-fold (construction laborers) higher risk of incurring maxillofacial fractures than did service and office workers. Injuries were most frequently (43%) caused by a thrown, projected, or falling object. Eighty-two percent of the fractures occurred in the midface region and at the skull base. Fifty-nine percent of the patients had concomitant injuries. In 69%, surgery was necessary, the mean duration of their hospital stay being 4.8 days. CONCLUSION: The probability of sustaining work-related maxillofacial traumata is correlated to the nature of the occupation. Farm and forestry workers are at the highest risk, most frequently injured by being struck by an object or an animal. The introduction of personalized safety measures should become obligatory in high-risk occupations.

Accidents, Occupational↗
PubMed2006

Reconstruction of the severely atrophic mandible using calvarial split bone grafts for implant-supported oral rehabilitation.

OBJECTIVES: This article describes reconstruction of the severely atrophic mandible using calvarial bone grafts for implant-supported prosthetic oral rehabilitation. The study aim was to evaluate the efficacy of the treatment by determining implant survival and complication rates, and the extent of the postoperative graft resorption. STUDY DESIGN: Ten patients who underwent the treatment were followed clinically and radiologically using panoramic radiographs and CT scans during a mean postoperative period of 30 months. RESULTS: Good bone healing was observable 6 months postoperatively. The height reduction measured on panoramic radiographs was insignificant (mean 0.68 mm). Only minor complications occurred. Implant survival was 95%. Prosthodontic treatment was successfully performed in all cases, resulting in an improvement of oral function. Histological analysis of 1 bone biopsy showed minimal resorptive changes in otherwise very dense bone. CONCLUSION: Augmentation using calvarial grafts is a promising treatment alternative for the severely atrophic mandible.

Aged↗
PubMed2006

Changes in the volume and density of calvarial split bone grafts after alveolar ridge augmentation.

OBJECTIVES: One main problem occurring after bone grafting is resorption, leading to insufficient bone volume and quality, and may subsequently cause dental implant failure. Comparison of graft volume and bone density of iliac crest and calvarial transplants determined by animal studies demonstrates significantly lower resorption of bone grafts harvested from the skull. This paper is the first clinical study evaluating bone volume and density changes of calvarial split bone grafts after alveolar ridge reconstruction. MATERIAL AND METHODS: Bone volume and density were determined using CT scans and the software program Dicom Works in a total of 51 calvarial grafts after alveolar ridge augmentation in 15 patients. CT scans were taken in all 15 patients immediately after grafting (T0) and before implantation after a postoperative period of 6 months (T1). In five patients (26 calvarial grafts), a 1-year follow-up was performed (T2). RESULTS: A mean volume reduction of 16.2% at T1 (15 patients) and 19.2% at T2 (five patients) was observed. Bone density was high--about 1000 Hounsfield units--and did not change during the 1-year period. At the time of implantation, 41 transplants were classified as quality 1 bone and 10 as quality 2-3 bone. Grafting area and the technique used for grafting (inlay or onlay graft) did not affect the postoperative bone volume reduction. Generalized osteoporosis did not increase the resorption rate of calvarial transplants. CONCLUSION: Based on these findings, calvarial split bone grafts are a promising alternative for alveolar ridge reconstruction in dental implantology.

Adolescent↗
PubMed2005

Long-term changes of hyoid bone position and pharyngeal airway size following mandibular setback by sagittal split ramus osteotomy.

INTRODUCTION: The purpose of this study was to determine long-term changes in hyoid bone position and pharyngeal airway size after mandibular setback osteotomies. MATERIAL AND METHODS: Serial cephalograms of 12 patients who underwent mandibular setback surgery were evaluated preoperatively, at 1 week, 6 months, and 14 months postoperatively, and finally after an average of 12 years. RESULTS: A mean setback of 5.6 mm was associated with a posterior and inferior movement of the hyoid bone. At long-term follow-up, the hyoid bone adapted horizontally to a position about 1.6 mm more posterior than its preoperative location. Immediately after surgery, the length of suprahyoid muscles correlated significantly with skeletal movements: suprahyoid muscles shortened by 4 mm but started lengthening after 1 year. Thereafter, it tended to correlate with the change of hyoid bone position rather than with skeletal relapse. Following the initial decrease after surgery, the size of the lower pharyngeal airway remained almost unchanged. The upper and middle pharyngeal airway sizes continued to decrease over the postoperative period of 12 years, and ultimately were smaller than their preoperative sizes by about 1.5 and 3 mm, respectively.

Adaptation, Physiological↗
PubMed2005

Surgical reconstruction of maxilla and midface: clinical outcome and factors relating to postoperative complications.

AIM: The aim of this study was to evaluate the success rate of different techniques of repairing maxillary and midfacial defects according to their extent. PATIENTS AND METHODS: In this retrospective study, 47 maxillary reconstructions in 41 patients were reviewed. Evaluation took place an average of 4.5 years postoperatively. The cases were divided into three groups according to the classification of Brown et al. (Br J Oral Maxillofac Surg 40: 183-190, 2002): Group 1: maxillary defects limited to one side (Class 2a); Group 2: bimaxillary defects (Classes 2b and 2c); Group 3: maxillary/midfacial defects (Classes 3 and 4). Most reconstructions were performed with non-vascularized bone grafts in the first patient group, whilst microvascular soft tissue flaps combined with free bone grafts were used in the second group, and re-vascularized osteocutaneous flaps in the third group. RESULTS: Overall flap survival was 79%. Dental reconstruction was successfully completed in 31 cases (66%). Postoperative infection leading to transplant loss was the main reason for failure. This complication was specifically associated with temporal osteomuscular flaps (50%) and free iliac crest grafts (61%) and was related to the extent of the defect. In the reconstructive methods evaluated here, associated radiotherapy had a minor influence on the occurrence of complications. CONCLUSION: Non-vascularized iliac bone grafts should be used sparingly in Class 2b, even in combination with microvascular flaps. There is a very limited indication for these grafts in Classes 3 and 4. Temporal osteomuscular flaps do not seem to be suitable for maxillary reconstruction.

Adolescent↗
PubMed2005

Midfacial reconstruction using calvarial split bone grafts.

OBJECTIVE: To evaluate the success rate of free calvarial grafts for midfacial reconstruction, the relevance of soft tissue coverage, and the influence of radiotherapy. DESIGN: Retrospective analysis. SETTING: University medical center. PATIENTS: Fifty-six patients (27 tumor cases, 24 trauma cases, and 5 others) underwent bony midface reconstruction using calvarial grafts in the past 11 years. Half of the patients with tumor were additionally treated with radiation. INTERVENTIONS: A total of 95 bone transplants were used for reconstruction of the zygoma, orbit, and nasal bone. Graft survival and complications were evaluated. Grafts with total and partial soft tissue coverage were compared. The influence of radiotherapy in the tumor patient group was determined. RESULTS: Graft survival was 95.8%. One nasal dorsum graft was totally resorbed. Infection occurred in 9 cases, leading to only 1 total and 2 partial graft losses. The incidence of dysfunction of the eye due to globe malposition after reconstruction of the orbital walls was low. A correlation between radiation and transplant loss as well as between soft tissue coverage and graft survival could not be found. CONCLUSIONS: For midfacial reconstruction, it is not necessary to fully cover calvarial bone grafts by the surrounding soft tissue. Even in patients who will undergo postoperative irradiation, calvarial bone grafts are a reliable alternative in selected cases.

Adolescent↗
PubMed2005

Arthroscopic lysis and lavage in different stages of internal derangement of the temporomandibular joint: correlation of preoperative staging to arthroscopic findings and treatment outcome.

PURPOSE: The study was designed to evaluate the outcome of standard arthroscopic lysis and lavage for internal derangement with various levels of severity by comparing the preoperative staging with arthroscopic findings and subsequent success rates. PATIENTS AND METHODS: Temporomandibular joint disorder in 23 patients (26 joints) who underwent arthroscopic lysis and lavage was preoperatively classified as Wilkes stages II-V based on the clinical and radiologic (magnetic resonance imaging) findings. Recorded arthroscopic findings were scored and compared with the stages. The patients were examined both preoperatively and after a mean follow-up of 22.7 months, using objective and subjective criteria. RESULTS: The arthroscopic findings showed a correlation between increasing scores and advancing stage. Postoperatively, the patients could be clearly classified into 2 groups with either satisfactory or poor clinical outcome. Overall success rate was 78.3% (18/23). The success rates were slightly lower for patients with advanced stages than for those of stages II and III. Patients totally unresponsive to the treatment were found in all stages. CONCLUSION: Arthroscopic lysis and lavage is a preferred treatment for different stages of internal derangement. Preoperative staging and corresponding characteristics of the arthroscopic findings do not seem to correlate with the prognosis of the treatment outcome.

Adult↗
PubMed2005

Reconstruction of orbital floor fracture with polyglactin 910/polydioxanon patch (ethisorb): a retrospective study.

PURPOSE: We sought to evaluate the effectiveness and the complications related to the use of Ethisorb (resorbable alloplastic material) in the reconstruction of orbital floor fractures. PATIENTS AND METHODS: We retrospectively reviewed the charts of all patients who underwent orbital floor fracture reconstruction with Ethisorb since 2001. We only included patients with a minimum follow-up of 3 months. The following data were recorded for every patient: age, gender, cause of trauma, time from trauma to surgery, signs and symptoms, concomitant ocular injuries, radiographic analysis, pertinent intraoperative findings (including the type of approach), follow-up time, and postoperative complications. RESULTS: Eighty-seven patients were included in the study. Twenty-one patients (24.1%) experienced postoperative complications. Of these, only 3 patients (3.4%) had permanent complications directly related to the Ethisorb membrane (diplopia, enophthalmos). Two of these patients required revision surgery and are discussed in the article. CONCLUSIONS: The results of our study demonstrate the effectiveness of Ethisorb in the repair of small-to-moderate orbital floor fracture defects (up to a maximum size of 2 x 2 cm).

Absorbable Implants↗
PubMed2005

Assessment of material- and technique-related complications following sagittal split osteotomies stabilized by biodegradable polylactide screws.

OBJECTIVE: The aim of this retrospective clinical study was to determine whether there are any material-related problems and increased occurrence of postoperative mandibular nerve and temporomandibular joint dysfunctions in connection with the use of biodegradable self-reinforced poly-L-lactide (SR-PLLA) screws for bone fixation after bilateral sagittal split osteotomies (BSSO). STUDY DESIGN: Forty consecutive patients who underwent BSSO and mandibular advancement that included fragment fixation using SR-PLLA screws were monitored for an average of 2.2 years postoperatively. RESULTS: The osteotomy sites healed uneventfully with no adverse reactions. The incidence of postoperative sensory disturbances of the inferior alveolar nerve was 27%. Symptoms of temporomandibular joint disorders (TMJD) observed preoperatively in 73% of patients were reduced to 48% after surgery. CONCLUSION: The occurrence of postoperative sensory disturbances and TMJD symptoms in this study did not deviate strikingly from that of other studies using conventional osteosynthesis. No specific complications related to the screw material were observed.

Absorbable Implants↗
PubMed2005

Long-term changes of hyoid bone and pharyngeal airway size following advancement of the mandible.

OBJECTIVE: To determine long-term changes in hyoid bone position and pharyngeal airway size after mandibular advancement, including evaluation of the relationship between length of suprahyoidal musculature and skeletal relapse. STUDY DESIGN: A cephalometric follow-up study (12 years) of 15 patients who underwent mandibular advancement surgery. RESULTS: The final position of the hyoid bone was more posterior than it had been preoperatively. Suprahyoidal musculature continuously lengthened from preoperatively to 12 years postoperatively. Total skeletal relapse at B-point and pogonion correlated significantly with postoperative stretch of suprahyoidal musculature. The upper and middle pharyngeal airways were narrower than their preoperative values. CONCLUSIONS: Mandibular changes influence hyoid bone position during the entire postoperative period, whereas stretching of suprahyoidal musculature seems to contribute to skeletal relapse. Mandibular advancement surgery alone possibly does not achieve a stable increase of pharyngeal airway size over a long-term period of 12 years.

Adolescent↗
PubMed2005

An alternative soft tissue analysis following mandibular setback by sagittal split ramus osteotomy.

OBJECTIVE: The objective of this study was to determine alternative ratios of soft-to-hard tissue movement after mandibular setback, taking skeletal relapse and differing patterns of facial divergence into account. STUDY DESIGN: Thirty patients were analyzed cephalometrically over a mean follow-up period of 14 months. RESULTS: The relationship between skeletal and soft tissue movements in the mentolabial folds and at the pogonion was 1:1. Final skeletal relapse was 0.8 mm at the B-point and 0.5 mm at the pogonion. Hence, the alternative ratios were 81% and 68%, respectively. The alternative ratio for the mentolabial sulcus was considerably lower in the low- than in the high- and medium-angle groups of patients. However, there was no statistically significant difference between the patient groups with different facial patterns. CONCLUSION: When the smallness of the measured relapse and the tracing error are taken into account, the difference between the alternative and the conventional ratios was insignificant.

Adolescent↗
PubMed2005

Mandibular setback by sagittal split ramus osteotomy: a 12-year follow-up.

Short- and long-term skeletal changes after mandibular setback were analyzed using bilateral sagittal split ramus osteotomy. Twelve patients who had undergone mandibular setback surgery between 1986 and 1990 were available for long-term cephalography on average 12 years after primary surgery. The mean amount of surgical setback had been 6.4 mm. After the first postoperative year, there was skeletal relapse of 1 mm at the B-point and pogonion (Pg), amounting to 14% of the initial skeletal setback. In contrast to condylar displacement and proximal segment rotation, osteotomy slippage was associated with positional changes at the B-point and Pg. From 1 to 12 years postoperatively, the B-point and Pg remained stable. Mandibular ramus and corpus length decreased 2.1 mm and 1.3 mm, respectively, indicating remodeling at the osteotomy sites and probably condylar resorption.

Adolescent↗
PubMed2005

The value of computed tomographic scanning in the diagnosis and management of orbital fractures associated with head trauma: a prospective, consecutive study at a level I trauma center.

BACKGROUND: Orbital fractures associated with head trauma are not always easy to diagnose. The real incidence of such fractures is unknown. The aim of this study was to evaluate the usefulness of routine primary computed tomographic (CT) scanning for diagnosis of orbital fractures in head trauma patients. METHODS: Over a 3-year period, 600 consecutive patients admitted with head trauma were examined clinically; these patients then underwent cranial helical CT scanning, irrespective of severity of head injuries and presence or absence of fracture-related symptoms. RESULTS: Orbital fractures were diagnosed on CT scan in 118 cases (19.7%). All patients with symptoms directly related to an orbital fracture had radiologically diagnosed fractures, compared with 58.3% of patients with isolated blepharohematoma and 3.8% of asymptomatic patients. CONCLUSION: CT scan of the orbits is indicated for any head trauma patient who presents either one or more symptoms directly related to an orbital fracture or just isolated blepharohematoma. CT scan of the orbits is not indicated in asymptomatic head trauma patients. Inclusion of the orbits in the scanning is recommendable only if a CT scan is already being obtained for a head injury. Clinical follow-up is important to detect any late-appearing symptoms. Accurate clinical examination still plays a crucial role in the diagnosis of orbital fractures.

Adolescent↗
PubMed2005

Oral rehabilitation after mandibular reconstruction using an osteocutaneous fibula free flap with endosseous implants. Factors affecting the functional outcome in patients with oral cancer.

BACKGROUND: The development of endosseous implants and free vascularized bone grafting has permitted increased possibilities of oromandibular reconstruction in patients with oral cancer. In this study, a concept combining surgical and prosthodontic treatments for mandibular fibula free flap reconstruction after tumor surgery was made based on a classification of bone defects. A follow-up study was performed to evaluate the treatment concept for oral rehabilitation in order to identify possible factors which may influence the functional result. MATERIAL AND METHODS: A follow-up examination included 28 patients who underwent the ablative tumor surgery and mandibular reconstruction during a 4-year period. The follow-up protocol included clinical examination, radiological evaluation, and an interview using a standardized questionnaire. The timing of the study was set to allow for a minimum 2-year follow-up (mean 45 months). RESULTS AND CONCLUSION: At the time of examination, prosthesis-based oral rehabilitation was completed in six patients (21%), and the prosthodontic work was still unfinished in four other patients. The other 18 had no dental prosthetic rehabilitation. Thirteen patients received a total of 37 oral implants, and 23 implants were functionally loaded. No implant loss was recorded. Oral functions such as speech, diet tolerance and oral competence were not directly affected by the presence of dentures. A decisive factor affecting the oral function was the extent of soft-tissue loss. According to the classification described here, the extent of the mandibular defect did not correlate with oral functions. The application of oral implants seemed to be advantageous for the oral rehabilitation of patients who had undergone intraoral resections.

Bone Transplantation↗
PubMed2005

Bi-directional distraction osteogenesis of the alveolar bone using an extraosseous device.

OBJECTIVES: In alveolar distraction, the bone segment tends to incline palatally or lingually, making rigid control of the segments difficult. The aim of this study was to evaluate the usefulness of a newly developed bi-directional extraosseous alveolar distractor (Medartis V2-Alveolar distractor) for pre- and perioperative vector management. MATERIAL AND METHODS: Seven patients with segmental alveolar atrophy following traumatic tooth loss were treated using the distraction device. The patients were followed up clinically and radiologically. Preoperatively, the initial vector for distraction was determined using CT by measuring the cross-section of the bone. The morphology of the alveolar bone was also analyzed in relation to the planned implant position. Postoperatively, the rate of osteogenesis was monitored with plane radiographs and CT scan. RESULTS: All cases had bone deficit at the anterior surface of the alveolar ridge, showing a typical inclination of the long axis of the bone. Using the distractor, vertical distraction and positioning of the segments with labial orientation was possible. After a consolidation period of 12 weeks on average, sufficient bone formation for implant installation was radiologically observable. Histologic and histomorphometric analysis of one bone biopsy showed very dense mineralized bone (area fraction=78%) with a multidirectional, complex architecture. Implant-supported prosthetic oral rehabilitation was successfully performed in all cases. CONCLUSION: All complications observed in this study were related to the bone deficiency at the anterior surface of the alveolar process. If the technique can be improved, this type of bi-directional distraction is a promising method for alveolar bone repair.

Adult↗
PubMed2004

Skeletal relapse after mandibular advancement and setback in single-jaw surgery.

PURPOSE: The aim of this study was to identify contributing factors to skeletal relapse by analyzing cephalometric changes after bilateral sagittal split ramus osteotomy. PATIENTS AND METHODS: This study included 60 consecutive patients who underwent either mandibular advancement (30 patients) or setback surgery (30 patients). There were 36 women and 24 men (mean age, 23 years). The radiographs of these patients taken immediately before operation, at 1 week, and 14 months postoperatively were studied. To analyze the influence of hyper- and hypodivergent facial patterns on the surgical outcome, the patients were divided into 3 groups according to the mandibulo-nasal plane angle. The position of the maxilla was also taken into account. RESULTS: Measured at B-point, skeletal relapse was 1.3 mm (30%) after mean advancement of 4.4 mm and 0.8 mm (12%) after setback of 6.0 mm. The magnitude of the surgical movement correlated with skeletal relapse. However, the correlation was not linear. Advancement of greater than 7 mm is associated with an increased tendency to relapse (r=0.52), but setback of more than 12 mm with a decreased tendency (r=-0.95). The retrognathic patients with a high mandibulo-nasal plane angle (hyperdivergence) had 30% higher relapse rate. Patients with hypodivergent facial patterns had less relapse in both advancement and setback surgery. CONCLUSION: Skeletal relapse was affected by magnitude of surgical movement and different facial patterns according to the mandibulo-nasal plane angle; however, influences of both factors were different between mandibular advancement and setback.

Adolescent↗