A titanium arch bar for maxillomandibular fixation in oral and maxillofacial surgery.
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Equipment Design↗
Biomedical subjects
Wenko Smolka
Publications and source records attributed to Wenko Smolka.
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↗
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↗
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↗
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↗
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↗
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↗
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↗
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↗
Analysis of soft tissue profile changes after mandibular advancement surgery.
The aim of this study was to analyze changes in soft tissue profile after mandibular advancement surgery, with special emphasis on the effect of skeletal relapse and different Class II facial patterns. The cephalometric radiographs of 30 consecutive patients (24 women and 6 men, mean age 23 years) who underwent sagittal split osteotomy were studied. The radiographs were taken immediately before operation, at one week and 14 months postoperatively. To analyze the possible influence of hyper- and hypodivergent facial patterns, the patients were classified into low- (4 patients), medium- (16 patients) and high-angle (10 patients) groups according to the magnitude of the mandibulonasal plane angle. The main movement occurred in the horizontal plane. Soft tissue pogonion and mentolabial fold were found to follow the underlying skeletal structures in a nearly 1:1 ratio. On final follow-up, skeletal relapse of 1.3 mm was measured at B-point and of 1.5 mm at pogonion. Taking the skeletal relapses into account, the ratios of both corresponding soft tissue references (alternative ratios) dropped to 60%. Soft tissue pogonion is the most reliable reference for the planning of mandibular advancement. The ratio of soft tissue movement to final skeletal position at the chin amounts to 60% for a realistic prediction. However, the low-angle group differed from other groups by showing a markedly low soft-to-hard tissue ratio of only 14% at pogonion and a high ratio of 109% at the mentolabial fold. However, these differences in ratios between the groups were statistically not significant.
Adolescent↗
Extensive augmentation of the alveolar ridge using autogenous calvarial split bone grafts for dental rehabilitation.
Free autogenous iliac bone is the most commonly used graft material for an extensive alveolar ridge reconstruction. The application of iliac bone, however, is associated with problems, such as transplant loss resulting from postoperative infection and late bone resorption. A bone-graft material more suitable than iliac bone is therefore still needed. This paper describes a concept for alveolar-ridge reconstruction using calvarial split bone, and the related surgical techniques. Clinical and radiological follow-up examinations were undertaken to evaluate the potential benefit of calvarial split bone in alveolar-ridge reconstruction. Between 1999 and 2002, 13 patients with a mean age of 54 years (range 31-70 years) underwent surgery, seven patients in the maxilla and six in the mandible. In four cases, wound dehiscence occurred postoperatively. In one of these cases, the dehiscence was associated with a local infection. However, no bone transplants were lost. After a mean follow-up time of 19.6 months, bone resorption, measured radiologically, was minimal. Endosseous dental implants were successfully installed and maintained. Satisfactory prosthetic rehabilitation was achieved in all patients. Our preliminary experience suggests that calvarial split bone may be regarded as a promising alternative to autogenous iliac bone in connection with extensive augmentation of the alveolar ridge.
Adult↗
Bone metastases: prognostic applications of cytometric DNA analysis.
OBJECTIVE: To examine DNA parameters as prognostic factors for developing metastases. STUDY DESIGN: Image cytometry was used to determine DNA content of 21 tumors and 28 metastases. DNA ploidy status, 2c deviation index (2cDI) and DNA malignancy grade (DNA-MG) (based on the variation of nuclear DNA content of tumor cells around the normal DNA [2c] peak) were examined for their prognostic value. RESULTS: Twenty of 21 tumors showed aneuploid content, and 1 tumor showed diploid DNA content. Twenty-one bone metastases showed aneuploid cells. In 6 cases both euploid and aneuploid cells were detected. In 1 metastasis only euploid cells were present. DNA-MG was increased in bone metastases (mean, 2.4) as compared to the corresponding primary tumor (mean, 2.2) in most of the cases. The mean value of the 2cDI was 30.07 in primary tumors and 42.5 in metastases. Twelve bone metastases had a higher 5cEE than did the primary tumor. CONCLUSION: Diploid and aneuploid cells were able to leave a tumor and establish metastases. DNA-MG and 2cDI were increased in metastases in comparison with the primary tumor, but even tumors with lower DNA-MG had metastatic potential.
Adult↗