Biomedical subjects

F W Neukam

Publications and source records attributed to F W Neukam.

At least 37 records · Page 2Linked to original sources

PubMed2002

Long-term results of distraction osteogenesis of the maxilla and midface.

Since the beginning of 1998, eight patients have been treated by osteodistraction to correct hypoplasia of the maxilla and midface of various origins. Among them were five patients who were treated by high LeFort I osteotomies and insertion of subcutaneous intraoral distraction devices in the malar region. In the remaining three patients, extraoral distraction devices were applied after LeFort II and III osteotomies. Distraction osteogenesis was successful in all cases, resulting in a mean sagittal bone gain measured parallel to the skull base of 9.0 mm (range 4.5-12.0) in the group treated with intraoral distractors and a mean of 20.3 mm in the extraoral distraction group (range 15.0-25.0). All patients were kept under orthodontic supervision before, during, and after osteodistraction. Long-term cephalometric and clinical evaluation after a mean follow-up period of 24 months in the intraoral distraction group (range 22-26) and 12 months in the extraoral distraction group (range 10-14) show stable results concerning the skeletal and dental relations. Long-term follow-up is necessary.

Adolescent↗

PubMed2002

Vascularization of the area between free grafts and irradiated graft beds in the neck in rats.

Inflammatory lesions of the vascular endothelium after preoperative radiotherapy often cause healing-delayed healing of free flaps in the irradiated graft bed. We investigated changes in neovascularization in the transition area between grafted tissues and irradiated tissues of the graft bed. We irradiated the neck(30 and 50 Gy total dose) in 102 Wistar rats and then grafted a free myocutaneous gracilis flap to the irradiated region of the neck 4 weeks later. We examined histologically the tissues of the graft, the transition area between the graft and the irradiated graft bed, and the graft bed. In contrast to control rats, the tissues in the irradiated animals showed a qualitatively reduced and a more irregular capillary distribution, with substantial fibrosis in the irradiated graft bed. We also found significant differences in vascularization and mean capillary lumen in the transitional zone between graft and graft bed in the irradiated rats compared with controls (P = 0.004 and P < 0.001, respectively). Both number and diameter of capillaries were reduced in the irradiated graft bed tissue. The graft failed to improve vascularization in the transitional zone between graft and irradiated tissue, so we conclude that it is the vascularization status of the bed tissue rather than that of the transplant tissue that is the limiting factor for graft healing.

Animals↗

PubMed2001

Orbital involvement in cherubism.

PURPOSE: To demonstrate the clinical, radiologic, and histopathologic features of a patient with orbital involvement in cherubism that prompted surgical treatment. DESIGN: Single interventional case report. INTERVENTION: Findings of the ophthalmic evaluation, computed tomography (CT) scans, intraoperative examination, and light microscopy of the specimens were analyzed. MAIN OUTCOME MEASURES: Globe displacement, orbital bony lesions detected on CT scans, histopathology, and postoperative results were assessed. RESULTS: A 27-year-old female was seen with a slowly progressive superonasal globe displacement and a temporal orbital mass bilaterally of 6 years' duration. She had a history of cherubism, but her cheeks and jaws had a normal appearance instead of the bilateral fullness of the lower half of the face typical of the disease. CT scans demonstrated multicystic bony lesions arising from the orbital floors bilaterally. The masses were excised using an anterior transcutaneous transseptal orbitotomy. Histopathology demonstrated numerous giant cells in a fibrovascular stroma, confirming the clinical diagnosis of cherubism. Postoperative recovery was complete. CONCLUSIONS: Orbital involvement in cherubism may develop beyond puberty, after stabilization or regression of the lesions in the jaws. Patients with cherubism should be routinely evaluated by an ophthalmologist.

Adult↗

PubMed2001

Morbidity of harvesting of chin grafts: a prospective study.

In a prospective study, 20 patients who underwent harvesting of chin grafts as outpatients, were followed up for 12 months (3 further patients with incomplete follow-up data were excluded from the study). Preoperatively and 7 days, 1, 3, 6 and 12 months postoperatively, follow-up data were assessed. Evaluation of the superficial sensory function of the inferior alveolar nerve was determined by the Pointed-Blunt Test and the Two-Point-Discrimination Test. Sensory disturbances were objectively assessed by testing thermal sensitivity with the "Pain and Thermal Sensitivity" Test (PATH Test). In addition, evaluation of the pulp sensitivity of teeth 35-45 was carried out by cold vitality testing. One week postoperatively, 8 patients were affected by superficial sensory impairment. 8 nerve territories showed hypoaesthetic reactions and 5 showed hyperaesthetic reactions. After 12 months, two patients still suffered from hypoaesthesia of one side of the chin. There was a statistically significant sensitivity impairment of the chin for all patients comparing the preoperative data of the Two-Point-Discrimination Test (left/right median: 8.17/8.17 mm, interquartile range (IQR) 1.00/2.00 mm) with the first postoperative measurement (left/right median 9.00/8.33 mm, IQR 1.67/2.66 mm). Comparing the latter to the last postoperative measurement there was significant tendency for regeneration of a nerve function (left/right median 8.00/7.84 mm, IQR 0.66/2.00 mm). In the PATH Test all hypoaesthetic areas could be identified by a reduction of thermal sensitivity. After the first postoperative examination 21.6% (n=38/176) of the examined teeth had lost their pulp sensitivity. After 12 postoperative months 11.4% (n=20/176) still did not react sensitively. Many of these were canines (n=8/20). Comparing the preoperative to the first postoperative examination, there was a significant reduction of pulp sensitivity. However, statistically significant recovery until the last postoperative follow-up could not be detected. The assessed data show that patients have to be informed extensively about disturbances of the inferior alveolar nerve function lasting longer than 12 months. Moreover, the loss of pulp sensitivity is a very frequent event which has always to be taken into account. Considering the high rate of complications with harvesting of chin grafts, more prospective trials should be done to find out whether there are other donor sites for autogenous bone which put less strain on patients.

Ambulatory Surgical Procedures↗

PubMed2001

A prospective electromyographic and computer-aided thermal sensitivity assessment of nerve lesions after sagittal split osteotomy and Le Fort I osteotomy.

PURPOSE: The purpose of this study was to determine the incidence of temporary and permanent sensory disturbance of the inferior alveolar nerve (IAN) after bilateral sagittal split osteotomy (BSSO) of the mandible and of the infraorbital nerve (ION) after Le Fort I osteotomy, as well as the rate of recovery of sensory function using subjective and objective measures. PATIENTS AND METHODS: Preoperatively and after 1 week, and 1, 3, 6, and 12 months postoperatively, sensibility in the distribution of 36 IONs after Le Fort I osteotomy and 24 IANs after BSSO in 19 patients were investigated by using sharp-blunt testing, 2-point discrimination, electromyographic recording, and thermal sensitivity (Pain and Thermal Sensitivity Test Device [PATH]) tests of the Adelta and C nerve fibers. RESULTS: With conventional clinical sharp-blunt and 2-point discrimination tests, the incidence of temporary impairment was 81% for the ION (29 of 36) and 83% for the IAN (20 of 24). The rate of permanent sensibility disturbance with conventional clinical testing was 6% for the ION and 15% for the IAN. Obvious recovery was found after 1 to 3 months for the ION, but it took 6 to 12 months for the IAN. In contrast, electromyography (EMG) testing showed lower rates of temporary sensory disturbance, namely, 54% (13 of 24) for the ION and 68% (15 of 22) for the IAN. Permanent sensory losses were not found. The results of the EMG test was confirmed by the PATH test. CONCLUSIONS: Objective tests for sensory disturbances show lower rates than the conventional tests. For quality control, preoperative and postoperative measurement and documentation of postoperative recovery of sensation is recommended.

Adolescent↗

PubMed2001

Distraction osteogenesis of the maxilla and midface using a subcutaneous device: report of four cases.

The use of distraction osteogenesis in the hypoplastic maxilla and midface is still controversial. Since the beginning of 1998, 25 patients have been treated with osteodistraction techniques for various reasons. Among them were four patients who were treated by high LeFort I osteotomies and insertion of a newly developed subcutaneous distraction device in the malar region. Distraction osteogenesis was successful in all four cases resulting in a mean sagittal bone gain of 12.0 mm (range 7-14) at the level of distractor fixation. All patients were kept under orthodontic supervision during osteodistraction. The final occlusal relation was satisfactory. Cephalometric measurements after distraction showed an anterior rotational movement of the midface region. As the question of relapse and further growth is still not clear, Delaire masks are used to stabilize the surgical result after removal of the distractor. The importance of long-term follow-up is stressed.

Adolescent↗

PubMed2001

Continuous and intermittent bone distraction using a microhydraulic cylinder: an experimental study in minipigs.

Distraction osteogenesis of the mandible is an option in the treatment of mandibular hypoplasia. Today, only intermittent distraction devices are available for clinical application. The aim of this study in minipigs was to evaluate continuous bone distraction using a microhydraulic cylinder. After a seven-day interval, continuous or intermittent distraction of 1.5 mm/day was established for 10 days. Immediately after active distraction, two animals and 20 days later the other four animals were killed and radiographs taken. The mandible was then removed en bloc and the distracted bone examined histologically. Intermittent distraction forces of up to 2500 kPa were necessary to move the cylinders' piston. The pressure needed for continuous distraction was considerably lower (1200-1300 kPa). While the specific histological structure of the varying zones in the distraction gap was similar after continuous and intermittent distraction, bone healing was accelerated after continuous distraction as shown by ultrasonography and scanning electron microscopy.

Animals↗

PubMed2001

Histomorphometric and densitometric changes in bone volume and structure after avascular bone grafting in the extremely atrophic maxilla.

AIM: To evaluate changes in volume and structure of bone after autogenous iliac crest bone grafting to the maxilla. To discover the predictive value of computed tomographic (CT) measurements of bone density and study their correlation with the results of histomorphometric analyses of bone structure. PATIENTS AND METHODS: In 25 patients with atrophic maxillae (mean age 47 years, range 15-71), who had onlay bone grafting and sinus floor augmentation with autogenous iliac crest bone, a CT analysis was carried out immediately before and after grafting, and 5 months (range 4-6) later, at the time of endosseous implantation. On both occasions, bone biopsy specimens were taken. HISTOLOGY OF BONE: After preparing and digitizing semithin sections, histomorphometry (NH-Image) was done to establish the ratio of trabeculae to medullary cavity. CT ANALYSIS: The available transverse and vertical bone and the bone density of natural and augmented bone were analyzed using the Simplant Program and the CT data. As reference, the bone density of the first cervical vertebra was used. By regression analysis, the correlation of CT bone density and histological bone structure was investigated. RESULTS: After a median healing period of 4.5 months, no significant changes were found in bone volume compared with the measurements made immediately after grafting. The changes in density in the cancellous portion of the grafted bone showed no correlation (correlation coefficient: +0.16) with the results of histomorphometric analysis of bone structure. CONCLUSIONS: The predictive value of measurement of bone density to evaluate bone structure on the basis of the D1-D4 classification needs to be reconsidered. The most favourable time for secondary implantation is 4-6 months after iliac crest bone grafting.

Adolescent↗

PubMed2001

Nasal airway changes after Le Fort I--impaction and advancement: anatomical and functional findings.

Twenty patients were studied prospectively to assess intranasal anatomical changes and functional changes resulting from a one-piece Le Fort I-osteotomy with anterior and superior positioning of the maxilla. Presurgical and 3 months postsurgical rhinological inspection, anterior rhinomanometry and acoustic rhinometry were performed. Interalar width was measured and cephalograms were used to assess maxillary movement. Rhinoscopically, three septal perforations (15%) were noticed. Turbinate enlargement was less common postoperatively. Interalar width increased significantly. These findings correlate with a significant increase in cross-sectional diameter at the Isthmus nasi revealed by acoustic rhinometry 3 months postoperatively. The mean total nasal airflow measured by anterior rhinomanometry was unchanged indicating no increase in resistance despite decreased intranasal dimensions in cases where the impaction is not higher than 5 mm.

Adolescent↗

PubMed2001

Experimental model for transplantation of a modified free myocutaneous gracilis flap to an irradiated neck region in rats.

In 102 Wistar rats (male, weight 300-500 g), a modified free myocutaneous gracilis flap was obtained from the groin and transplanted to the neck. To create a pre-irradiated transplant bed, a local area of the neck was irradiated preoperatively with 30 Gy (fractionation: 3 x 10 Gy) in 30 animals, and with 50 Gy (fractionation: 5 x 10 Gy) in a further 30 animals. The interval between preoperative irradiation and transplantation was 4 weeks. Forty-two animals received no such preoperative radiation. The evaluation of healing and the success of the transplanted flap was based on a clinical assessment, carried out on postoperative days 1 7. Testing for significant differences was done nonparametrically using the Kruskal-Wallis test. The survival rate in the nonirradiated animals was 86%. In contrast, the healing of the free flaps in the pre-irradiated transplant bed was significantly lower (P=0.003) 76%, after irradiation with 30 Gy and 50% after 50 Gy. The significant difference (P=0.020) in survival rates after irradiation with 30 and 50 Gy was evidence for the dependence of successful healing on the preoperative radiation dose. Transplantation of the free myocutaneous gracilis flap to a previously irradiated transplant bed in the region of the neck is a suitable model for investigating the healing of free transplants to irradiated tissue. The success rate observed in non-irradiated transplant beds is comparable to that seen with other flap models in rats.

Anastomosis, Surgical↗

PubMed2001

Langerhans cell granulomatosis: a case report of polyostotic manifestation in the jaw.

We report the case of a 43-year-old woman who suffered from a polyostotic form of Langerhans cell granulomatosis (LCG) in the mandible and maxilla. The course of the disease was followed for more than 14 years. The disease's progression finally required subtotal resection of the mandible and reconstruction with a microvascular fibula graft. The literature is reviewed for diagnostic and treatment concepts based on the different stages of LCG.

Adult↗

PubMed2001

The role of angiography in the lower extremity using free vascularized fibular transplants for mandibular reconstruction.

BACKGROUND: Fibular osteocutaneous free tissue transfer represents the work horse procedure in the reconstruction of large oromandibular defects. Before the fibula is harvested the blood supply of the lower leg and foot should be examined, as the perfusion may be based predominantly on the peroneal artery and venae comitantes. To avoid postoperative ischaemia of the lower leg, adequate perfusion must be guaranteed before sacrificing the peroneal vessels. Anatomical variations and peripheral arterial occlusive disease add to the risk of ischaemia. Various methods of evaluating the blood supply have been described. MATERIAL AND METHODS: Fifty-two consecutive cases of fibular flaps were evaluated to study the arterial blood supply of the lower extremity. For angiography, the right femoral artery was punctured using the Seldinger technique and a total of 20-25 ml contrast medium (Imeron 300) was infused and images required at a rate of 0.5/sec. RESULTS: A patent three-vessel supply to both feet could only be detected in 21 patients. Thirty-one angiograms revealed anatomic and/or arteriosclerotic alterations. Angiography provided accurate information in all patients and allowed successful fibular transfer in those patients who were found preoperatively to have regular conditions. CONCLUSION: Preoperative assessment of the blood supply of the lower extremity is important before fibular osteocutaneous free tissue transfer. We advocate angiography as interpretation is not examiner dependent.

Adult↗

PubMed2001

Diagnostic and prognostic relevance of expression of human telomerase subunits in oral cancer.

Telomerase activity (TA) is associated with most malignant human tumors but is not detected in normal somatic cells with a few exceptions. Three major subunits (hTR, hTP1 and hTERT) of telomerase have been identified. To investigate the clinical implications of the mRNA detection of these components as useful diagnostic and prognostic markers in oral cancer, we examined TA, hTR, hTP1 and hTERT mRNA expressions in 46 oral squamous cell carcinomas (OSCC) and 15 normal oral mucosal tissues from healthy volunteers using a highly sensitive TRAP assay and RT PCR. In all specimens hTR and hTP1 mRNA were detected regardless whether TA was expressed or not. On the contrary, a significant correlation between hTERT expression and TA was shown indicating that the activity of telomerase could be regulated by the extent of hTERT transcription. In addition, hTERT expression showed close association to malignancies. None of the normal mucosal specimens expressed the hTERT subunit, but 76% (35/46) of the tumor specimens did. None of other clinico-pathological and prognostic parameters showed significant relationship with TA or hTERT expression. These results suggest that the detection of hTERT expression may be another useful diagnostic marker, especially for early detection of OSCC, and for distinguishing healthy tissues from neoplastically transformed ones.

Carcinoma, Squamous Cell↗

PubMed2000

[Vascularization of free myocutaneous gracilis flaps in replacement transplantation after preoperative radiotherapy. An experimental study].

BACKGROUND: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial carcinomas of the head and neck region, inflammatory changes to the connective tissue and vascular endothelium are observed. These processes may lead to a delay in healing of free flaps in the irradiated transplant bed. The aim of the study was to investigate qualitative and quantitative changes in vascularization in irradiated and regular transplant beds. MATERIAL AND METHODS: In Wistar rats (male, weight 300 to 500 g) undergoing preoperative irradiation of the neck region with 3 times 10 Gy (30 animals) and 5 times 10 Gy (30 animals) and non-irradiated rats (42 animals), a free myocutaneous gracilis flap taken from the groin was transplanted to the irradiated region of the neck. The time interval between irradiation and transplantation was 4 weeks. On day 3, 4, 5, 7, 14 and 28 post operation, the capillary sprouting, structural changes and the distribution patterns were analyzed by H & E and immunohistochemical staining (goat-F[ab]-2-anti-von Willebrand factor antibody). Three histological sections (2 to 4 microns) per sample were investigated histomorphometrically, qualitatively and quantitatively (ratio capillary area/total area, and capillary lumen) by NH-image-digitized measurement. A statistical analysis was performed using the Mann-Whitney test. RESULTS: In contrast to non-irradiated rats, irradiated animals showed a qualitatively reduced and a more irregular capillary distribution with more marked pericapillary fibrosis in the irradiated transplant bed. Quantitatively, the ratio capillary area/total area, as a marker of improved capillarization was significantly reduced in the transition area transplant/irradiated transplant bed and in irradiated transplant bed tissues in contrast to the non-irradiated control group (p = 0.004). Also, from day 14 to 28 a significant decrease was found in the transition area between transplanted tissues and irradiated transplant bed tissues in irradiated animals (p = 0.005). The median capillary lumen size also decreased significantly in the transition area and transplant bed in 30 Gy and 50 Gy irradiated animals (p < 0.001 and p = 0.003). CONCLUSIONS: Following irradiation, vascularization of the soft tissue flaps is both reduced and delayed. This is evidence of delayed healing of soft tissue transplants in transplant beds irradiated prior to surgical interventions. Further optimization of the time interval between radiotherapy and surgery and the total radiation dose are therefore needed.

Animals↗

PubMed2000

[Implantology].

Endosseous osseointegrated implants have become an integral part of the treatment scheme for the prosthetic reconstruction and rehabilitation of masticatory function following scientific studies of the reactions between implant and soft and hard tissues. Furthermore, implants offer good chances for prosthetic rehabilitation in the insufficient bone site, if the extremely atrophic jaw is to be reconstructed by grafting procedures with avascular and vascular grafts, by guided bone regeneration, by distraction osteogenesis, by bone substitutes and in the future by osteoinductive proteins in order to prepare the conditions for implant insertion. Those reconstruction procedures combined with implants become often necessary, if complicated hard and soft tissue defects of the skull have to be reconstructed to create the prerequisites for the stabilisation of epitheses or to insert implant-supported devices.

Bone Regeneration↗

PubMed2000

[Possibilities of computer graphics simulation in orthopedic surgery].

BACKGROUND: In addition to standard X-rays, photographic documentation, cephalometric and model analysis, a computer-aided, three-dimensional (3D) simulation system has been developed in close cooperation with the Institute of Communications of the Friedrich-Alexander-Universität Erlangen-Nürnberg. With this simulation system a photorealistic prediction of the expected soft tissue changes can be made. Prerequisites are a 3D reconstruction of the facial skeleton and a 3D laser scan of the face. After data reduction, the two data sets can be matched. Cutting planes enable the transposition of bony segments. The laser scan of the facial surface is combined with the underlying bone via a five-layered soft tissue model to convert bone movements on the soft tissue cover realistically. CONCLUSION: Further research is necessary to replace the virtual subcutaneous soft tissue model by correct, topographic tissue anatomy.

Cephalometry↗

PubMed2000

[Continuous bone distraction with the help of a microhydraulic cylinder].

Distraction osteogenesis of the mandible is one treatment option in mandibular hypoplasia. Usually, a non-continuous distraction mode is applied. The aim of the present study was to establish continuous bone distraction using a microhydraulic cylinder. Using a submandibular approach, the mandible was dissected subperiostally on one side in four mini-pigs; corticotomy was performed and the microhydraulic cylinder fixed with two bicortical screws. The hydraulic tube was connected with an automatic hydropneumatic injector system. Following 7 days at rest, a continuous distraction of 1.5 mm per day was performed for 14 days. After 2 and 4 weeks postoperatively, the animals were killed and X-rays taken. The mandible was then removed en bloc and microscopic evaluation of the sections was performed. The microhydraulic cylinder was easy to apply and to handle. The continuous stimulus did induce direct mineralisation of longitudinal oriented collagenous fibre bundles. Bony regeneration seems to be accelerated, which might reduce the postoperatively stabilizing phase.

Animals↗

PubMed2000

[Distraction osteogenesis of the mandible in craniofacial abnormalities].

In recent years, lengthening the human mandible by distraction osteogenesis has become an accepted treatment to correct severe mandibular hypoplasia. Using intraoral unidirectional and extraoral bidirectional distraction devices we report about our experiences and results in the application of the bone distraction technique in four selected cases of syndromal disease, including various forms of mandibular hypoplastic malformations. The patients involved were a boy with Pierre Robin syndrome, a girl with unilateral facial hypoplasia in Goldenhar's syndrome, a case with Nager's syndrome, and a rare case of midline deficiency caused by partial deletion of chromosome 18 (18p-syndrome). The distraction period lasted from 6 to 30 days and new bone formation, ranging from 6 to 28 mm, was achieved.

Adolescent↗