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Biomedical subjects

U Wahlmann

Publications and source records attributed to U Wahlmann.

13 recordsLinked to original sources
PubMed2003

[Adenomatoid odontogenic tumor in calcifying odontogenic cyst].

BACKGROUND: Adenomatoid odontogenic tumors (AOT) and calcifying odontogenic cysts (COC, Gorlin's cyst) are rare benign specificities of odontogenic tumors. Most odontogenic tumors are lesions of embryonic odontogenic tissue. Radiographically, odontogenic tumors may mimic an odontogenic follicular cyst. CASE REPORT: This paper describes the case of an 11-year-old female patient with a remarkable combination of these two entities. The lesions were found at the site of a retained first premolar and a persistent deciduous tooth 84 of the right lower jaw. Without clinical symptoms the tumor had expanded the vestibular cortical bone of the premolar region. Radiographically, the lesion appeared as a typical follicular cyst. During the operation, excochleation of the cyst was performed and the premolar was extracted. Finally, the epithelium of the cyst was treated by curettage. The histologic specimen revealed the diagnosis of an adenomatoid odontogenic tumor (AOT) in a calcifying odontogenic cyst (COC). DISCUSSION: The described case shows that symptoms of odontogenic tumors are usually nonspecific. For that reason one should always take a biopsy for histological investigation when patients present atypical cysts of the jaw. In rare cases even malignant odontogenic neoplasms could occur.

Bicuspid↗
PubMed2001

[Therapy monitoring with 2-(18F)-FDG positron emission tomography after neoadjuvant radiation treatment of mouth carcinoma].

BACKGROUND: Combined protocols of radiation therapy and surgical resection, as applied in advanced oral cancer, rely on objective and early assessment of treatment response to radiation therapy. Non-responders require immediate radical salvage surgery even in spite of substantial operative risks, while complete or subtotal response may give reasons for continuing the conservative approach. Therefore, we investigated radiation response by FDG-PET for early monitoring of oral cancer. PATIENTS AND METHODS: In 30 patients with advanced stages of oral cancer (Table 1), FDG-PET (Siemens, ECAT EXACT 922) was performed within 4 weeks after completion of preoperative radiation therapy (36 Gy). SUV of tumor regions were compared to the histologic degree of tumor regression in complete resection specimens. Statistic evaluation included correlation analysis of SUV vs tumor regression and ROC analysis for SUV cut-off values. RESULTS: While low FDG accumulation was found in tumors with histological complete remission (2.3 +/- 0.4) as well as in cases of residual tumor (3.4 +/- 1.8), high FDG uptake was a rather specific indicator of vital tumor tissue (Figure 2). Significant correlation (p = 0.045) between postradiotherapeutic FDG-uptake and histological tumor regression was recognized. A SUV > 2.75 as a clinically practicable threshold value for the identification of residual vital tumor resulted in a specificity of 88%, sensitivity of 68%, a positive predictive value of 94% and a negative predictive value of 50% (Figure 3). Based on our actual follow-up data we could not confirm a significant correlation between postradiotherapeutic SUV and patients' survival. CONCLUSION: Within a standardized protocol, FDG-PET recognize treatment response to radiation therapy in oral squamous cell carcinoma with a reasonable specificity and thus provides a basis for further therapeutic decisions. An increased SUV (> 2.75) may be the rational to justify an aggressive surgical approach even when patients face substantial surgical or anesthesiological risk. However, the posttherapeutic pattern of glucose uptake varies with the applied treatment modalities and has to be explored for the protocol applied.

Adult↗
PubMed1999

[Tissue damage and regeneration after laser surgery using different scanning systems].

INTRODUCTION: Laser systems are frequently used in dentistry. New laser scanner technologies are promising more homogeneous ablation of pathological ablations of the skin and mucosa. The theoretical advantages of these systems have not yet been sufficiently evaluated by histological findings. For this reason, we compared two laser scanners with different scanning patterns in this study (Silktouch and Swiftlase, by Sharplan, Germany). MATERIALS AND METHODS: In this animal study (79 male Osborn-Mendel rats), skin defects of 3-mm diameter were lasered on to the backs of the animals, one for each method mentioned above (defocused laser, Swiftlase, and Silktouch). The histological investigations were conducted, depending on the time after surgery (9 h, 1, 2, 3, 4, 5, 6, 7, 9, 11, or 13 days). On the clinical site, we evaluated the visible ablation rate, homogeneity and morphology of the wound surface and the degree of carbonization. In the histomorphological investigations, we determined the degree of thermal damage as well as the morphology of the necrotic area and reepithelization pattern of the surface. RESULTS: The Silktouch scanner clinically showed a homogeneous ablation rate with less carbonization than the Swiftlase scanner. In the histological specimen, this correlated with an increase in the tissue ablation rate and decreasing thermal damage to the surrounding tissue. Especially in the early wound-healing period, there was a more rapid reepithelization after the use of the Silktouch scanner. These differences could not be evaluated in the later wound-healing period. Compared to the defocused laser ablation, both scanning systems seem to have benefits within these parameters. CONCLUSIONS: The results of this study seem to show a diminished perifocal damage and reduced clinical postoperative morbidity achieved by using laser scanning systems. Compared to the Swiftlase laser, the Silktouch seems to deliver better results.

Animals↗
PubMed1999

Clinical and microbiological efficacy of single dose cefuroxime prophylaxis for dental surgical procedures.

In a prospective controlled randomised trial of 59 patients the effect of a single dose of cefuroxime before multiple tooth extractions on the clinical findings and occurrence of bacteraemia was studied. In one group 1.5 g cefuroxime was administered intravenously 10 min before start of surgery. A total of 118 blood samples were collected after 10 and 40 min. The cefuroxime group had a significantly lower rate of bacteraemia (33%) compared with the control group (86%). The predominant bacteria were gram-positive cocci. Fifty four different strains of bacteria were isolated, of which most were susceptible to cefuroxime. However seven strains which were susceptible to cefuroxime in vitro, were isolated from blood cultures of the treated group. Serum concentrations of cefuroxime ranged from 52.3 to 141.6 mg/l at 10 min and 32.6 to 91.8 mg/l at 40 min with a mean of 78.6 and 55.1 mg/l respectively. The only other factor which had a significant influence on the rate of bacteraemia was the number of extracted teeth. Oral hygiene and periodontal status did not significantly affect bacteraemia. There were no wound infections in any of the groups. During these dental interventions, sufficient plasma levels of antibiotic prevented bacteraemia. Selected patients might benefit from single-dose-prophylaxis with cefuroxime in preparation for dental surgery.

Adult↗
PubMed1999

Acoustic airway profiles in unilateral cleft palate patients.

OBJECTIVE: This study investigates the nasal airway in unilateral cleft palate patients by means of a noninvasive, objective diagnostic method that provides topographic information about the airway profile. DESIGN: A consecutive sample of patients was measured. SETTING: Cleft palate rehabilitation center of the University of Mainz, Germany. PATIENTS: Forty-nine subjects were investigated: 34 full-grown patients with complete unilateral cleft lip and palate and 15 controls with subjective normal nasal patency. INTERVENTION: A transnasal series of three acoustic measurements of nasal volume was performed per nostril; measurements were taken both before and after decongestion with 0.3 mg xylometazoline per nostril. Minimum cross-sectional area, nasal volume, and decongestion capacity were calculated for both the cleft side and the contralateral side and for both nasal sides in controls. RESULTS: Pathologic obstructions (<0.4 cm2) were detected on the cleft side in 75% of patients but were detected in only 15% of patients on the contralateral side (p < .001). The valve area of the cleft side (0.32 +/- 0.2 cm2) yielded significantly (p < .001) lower cross-sectional values compared with the contralateral side (0.56 +/- 0.1 cm2). Total nasal volume was determined to be 35% smaller on the cleft side (p < .001). Significantly higher decongestion capacity was verified on the cleft side, thus indicating mucosal hypertrophy. CONCLUSION: Despite a wide range of interindividual variability, we recognized a characteristic "descending W"" airway pattern in cleft palate patients. Acoustic rhinometry seems to be a powerful tool for acquiring topographic information about the individual airway profile. It has proven helpful in visualizing the location and amount of pathologic obstructions, rendering it especially useful for preoperative investigation and quality control in corrective cleft nose surgery.

Acoustics↗
PubMed1998

Objective evaluation of velopharyngeal function by acoustic reflection measurements.

OBJECTIVE: To investigate whether acoustic pharyngometry is capable of discriminating velopharyngeal mobility in cleft and non-cleft subjects by determination of epipharyngeal volume changes with active muscle function. DESIGN: Case control study, consecutive sample. SETTING: Cleft palate rehabilitation centre. PATIENTS: Thirty-three consecutive cleft palate patients, among them 10 following pharyngeal flap surgery and 32 controls without velopharyngeal pathology. INTERVENTION: Transnasal acoustic measurements of airway cross-sectional area in the state of relaxed and tensed pharyngeal muscles. Determination of epipharyngeal volume changes by integrating the difference of the airway profile from the choane for a distance of 5 cm (EV0-5). Measurements of defined changes in the epipharynx served as reference. RESULTS: Acoustic pharyngometry is capable of discriminating (P < 0.05: U test, Mann-Whitney) the volume effect of velopharyngeal mobility in CP patients (6.5 cm3) from the control group (8.0 cm3). A 'pharyngeal flap type' and a 'non-pharyngeal flap type' of restriction was observed. The individual effect of velopharyngoplasty on pharyngeal mobility can thus be determined. CONCLUSION: Acoustic pharyngometry is a non-invasive, quantitative investigation technique which seems well suited for the evaluation of velopharyngeal mobility. We expect it to be a helpful tool in objectively monitoring the effect of therapeutic intervention on velopharyngeal mobility, and it may provide a better understanding of the pattern of movement in CP patients.

Acoustics↗
PubMed1998

[Value of (F18)-2-fluorodeoxyglucose PET scanning in staging mouth cavity carcinoma. Comparative evaluation of PET findings before and after preoperative radiochemotherapy with histological and computerized tomography findings].

OBJECTIVE: The lack of sensitivity and specificity of conventional imaging techniques based on morphological critera is responsible for considerable limitations in the staging and surveillance of oral cancer. Therefore, this study investigates the contribution of [F18]-2-fluordesoxyglucose (FDG) positron emission tomography (PET) to tumor management with special regard to lymphnode involvement and therapeutic monitoring after radiotherapy. DESIGN: Prospective observational study. PATIENTS: Twenty-one patients with advanced oral cancer, predominantly T3/T4. INTERVENTION: FDG-PET scans before and after preoperative radio(chemo)therapy. Standardized uptake values (SUV) were determined for the tumor site and lymphnode areas. PET scans were correlated to histological findings after ablative tumor surgery. RESULTS: FDG-PET yielded superior sensitivity and specificity for tumor and lymphnode assessment. The effect of radiotherapy was reflected by the metabolic activity of the tumor, which shows a close correlation between the decrease of FDG uptake and histologic tumor regression. PET detected distant metastases and simultaneous tumors. CONCLUSION: FDG-PET is a challenging imaging technique with the potential to improve staging procedures for oral cancer. In the monitoring of metabolic activity of the tumor in the course of radio(chemo)therapy, FDG-PET allows objective measurement of the treatment response.

Aged↗
PubMed1998

Objective, noninvasive evaluation of velopharyngeal function in cleft and noncleft patients.

OBJECTIVE: The purpose of this study was to investigate a new diagnostic method that provides an approach to noninvasive, objective measurement of velopharyngeal movement by acoustic determination of epipharyngeal volume changes with velopharyngeal muscle function. DESIGN: This was a case control study, using consecutive samples. SETTING: This study took place at the Cleft Palate Rehabilitation Center of the University of Mainz, Germany. PATIENTS: Subjects were 29 consecutive cleft lip and palate (CLP) patients and 31 controls (21 patients with dysgnathia and 10 healthy volunteers). INTERVENTION: A series of transnasal acoustic measurements (pressure wave: 55 dB for 2 milliseconds) of epipharyngeal volume were performed with the pharyngeal muscles relaxed in end-expiration and while the velopharyngeal orifice was closed, with the difference in volume representing maximal pharyngeal movement. RESULTS: Cleft palate patients yielded significantly lower values of velopharyngeal movement (6.5 cm3) than did the control group (8.0 cm3) (p < .05; Mann-Whitney U test). Overlapping ranges of values were measured for the C(L)P and control groups. The least mobility (4.75 cm3) was measured in patients who had undergone pharyngeal flap surgery. Different patterns of restriction were observed in patients with and without a pharyngeal flap. CONCLUSION: Acoustic pharyngometry may provide access to noninvasive quantitative measurement of velopharyngeal movement and a better understanding of the pattern of movement in C(L)P-patients. We expect it to be a helpful tool in objectively monitoring the progress of logopedic therapy.

Acoustics↗
PubMed1997

[Acoustic reflection position monitoring of tracheal cannulae. A contribution to quality assurance?].

Non-invasive acoustic airway monitoring was evaluated in an experimental study. Recording amplitude and travel time of acoustic pulse response, an area-distance function of the cross sectional dimensions of the endotracheal tube and the adjacent airway was calculated to obtain an acoustic pattern of the airway. Measurements on models and excised human cadaver lungs were performed to discover whether displacement or obstruction of the artificial airway can be detected in the acoustic equivalent. Regression analysis revealed a close correlation between displacement of tracheostomy tubes and the shifting of the acoustic area-distance function (corr. coeff. 0.97-1). Dispersion analysis confirmed reasonable reliability (coeff. of variation 0.6-2.1%). Location and amount of obstruction could likewise be identified. Thus acoustic mapping provides an adequate approximation of the true geometry of tracheostomy and endotracheal tubes. We conclude that acoustic monitoring may provide a powerful tool to achieve primary prevention of airway disturbances in intubated and mechanically ventilated patients, as geometrical changes of airway configuration can be detected even before they cause substantial effects on respiratory metabolism.

Acoustics↗
PubMed1997

Acoustic monitoring of the artificial airway--experimental results.

Non-invasive acoustic airway-monitoring was evaluated in an experimental study. Recording amplitude and travel time of acoustic pulse response, an acoustic pattern of airway's geometry was then calculated. Measurements on models and excised human cadaver lungs were performed to discover whether displacement or obstruction of the artificial airway could be detected by its acoustic equivalent. Regression analysis revealed a close correlation between displacement of tracheostomy tubes and the shifting of the acoustic area-distance function (corr. coeff.: 0.97-1) and an adequate correlation between acoustic and planimetrical determination of cross-sectional area within the tubes (corr. coeff.: 0.78). Dispersion analysis confirmed reasonable reliability of acoustic cross-sectional measurements (Coefficients of variation: 0.6-2.1%). The acoustic mapping thus provides an excellent approximation of the true displacement and/or obstruction of tracheostomy and endotracheal tubes. We conclude that acoustic monitoring may provide a helpful tool for achieving an early warning system of airway disturbancies in intubated and mechanically ventilated patients, as geometrical changes of airway configuration may be detected before they lead to relevant effects on respiratory metabolism.

Acoustics↗
PubMed1997

[Extracorporeal shock-wave therapy. Experimental basis, clinical application].

The purpose of our studies was to investigate experimentally the dose-dependent effects of extracorporeal shock waves on tendon and bone and to unveil therapeutic possibilities in tendinopathies and pseudarthroses. In animal experiments, both positive and negative influences were exerted by shock waves, depending on the initial situation and on the power of the applied shock waves. In prospective clinical trials positive effects were found in the treatment of persistent tennis elbow, plantar fasciitis, calcifying tendinitis, and pseudarthrosis. Our data show that extracorporeal shock waves may provide analgesic, resorptive and osteo-inductive reactions with nearly no side effects. However, the high cost of apparatus and staff prevents a routine application. Extracorporeal shock waves thus remain a last alternative before the indication is made for an operative procedure.

Achilles Tendon↗
PubMed1997

Nasal airway in cleft-palate patients: acoustic rhinometric data.

The objective of this study was to investigate an instrumental assessment technique for acquiring reproducible, metric data on the nasal airway in cleft-palate associated nasal dysplasia. A consecutive sample of 23 unilateral, 17 bilateral CLP patients and 15 controls with subjective normal nasal patency from a cleft-palate rehabilitation centre were studied. A series of transnasal acoustic measurements (pressure wave: 55 dB for 2 ms) of nasal volume were performed before and after topical decongestion with 2 x 0.3 mg of xylometazoline. A standardized regimen of acoustic parameters of the nasal valve and the adjacent segment of the nasal cavity were calculated. The cleft side yielded a significantly (40%) lower nasal volume than the non-cleft side. Considerably lower values were recorded for the isthmus of the cleft side (0.31 cm2) compared with the non-cleft side (0.52 cm2). Decongestion capacity was higher in the posterior segment, indicating cleft-side massive mucosal hypertrophy. In bilateral CLP, the isthmus measured 0.46 cm2. By decongestion, individual side differences were reduced in unilateral CLP patients but enhanced in bilateral clefts. The prevailing pattern of the cleft-side airway profile can be described as a 'descending W'. Acoustic rhinometry is a non-invasive, instrumental assessment technique for acquiring reproducible metric data of nasal dysplasia in cleft-palate patients. By identification of the location and amount of nasal obstruction, it provides topographic information about the individual airway profile. It is suitable for the longitudinal investigation of nasal-airway development, as well as the preparation and follow-up of corrective rhinosurgery.

Acoustics↗