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Biomedical subjects

H A Merten

Publications and source records attributed to H A Merten.

At least 19 recordsLinked to original sources
PubMed1996

The functional palatorrhaphy in the treatment of obstructive sleep apnoea.

We have developed a new operation for the surgical treatment of obstructive sleep apnoea, which we called functional palatorrhaphy. This preserves the posterior border of the soft palate and allows a controlled repair of the aponeurosis of the soft palate muscle. We combine the palatorrhaphy with a standard or a modified chin osteotomy with advancement of the base of tongue. In our first five treated and re-evaluated patients with severe obstructive sleep apnoea syndrome, who did not respond to conservative treatment, the operation was successful. All patients but one were considerably improved or cured of their symptoms.

Chin↗
PubMed1996

Results of treatment of fractures of the atrophic edentulous mandible by compression plating: a retrospective evaluation of 84 consecutive cases.

PURPOSE: This article introduces a simple and reproducible classification of the degree of atrophy in fractures of the atrophic edentulous mandible, and evaluates the results of treatment in 84 consecutive fractures based on this classification. MATERIAL AND METHODS: Eight-four fractures of the edentulous mandible, with a height at the fracture site of < or = 20 mm, were included. Using the ratio of actual plate width to plate width on the postoperative radiograph, the actual height of the mandible at the fracture site was calculated. Twenty-five fractures (30%) were in the Class I atrophy group (height at the fracture site 16 to 20 mm), 33 fractures (39%) occurred in Class II atrophic mandibles (height 11 to 15 mm), and 26 fractures (31%) were seen in extremely atrophic Class III mandibles (height < or = 10 mm). The treatment was performed by compression plating without any postoperative MMF. Primary bone grafting was used in six cases (7%) because a partial bone defect was present at the fracture site. RESULTS: In 81 (96.5%) of the 84 fractures an uncomplicated, solid, bony union was achieved. Three major complications occurred: one osteomyelitis and two nonunions. The two nonunions occurred in bilateral fracture of an extremely atrophied mandible (Class III atrophy). Minor soft tissue infections, without interference with fracture healing, were observed in six cases (7%). CONCLUSIONS: Because there is an obvious relation between the height of the mandible and the incidence of complications in fracture healing, a special classification of the degree of atrophy is needed. In fractures of the extremely atrophic mandible (Class III atrophy) periosteal degloving should be avoided and supraperiosteal placement of plates is recommended. Compression osteosynthesis has proved to be a successful method, with minimal impairment of the patient and a low frequency of serious complications.

Adult↗
PubMed1996

Ectopic bone formation with the help of growth factor bFGF.

In the present study, basic fibroblast growth factor and a non-resorbable biological matrix (Endobon) were used to help to induce ectopic bone formation in the subdermal fatty tissue of the Göttingen miniature pig. In the early phase, bFGF improved the recipient conditions by enhancing angioneogenesis and helping to provide pluripotent mesenchymal cells. However, vitally transplanted bone cells were necessary in order to ensure successful bone formation. The Endobon only served as an osteoconductive matrix.

Adipose Tissue↗
PubMed1996

The multipoint contact plate in fracture treatment of the atrophied mandible: animal study and clinical application.

Rapid consolidation of osseous fractures requires stable immobilization of the fragments. In the atrophied mandible, the nutrient supply should be ensured by protecting the periosseous soft tissue, i.e., the periosteum. In the conventional placement of osteosynthesis plates, however, the subimplant nutrition is restricted because of the high surface pressure between the osteosynthesis plate and bone. In order to improve the subimplant nutrient supply, we designed a new osteosynthesis plate with a "knobbed" underside enabling multipoint contact. Histomorphologic comparative studies were conducted on 16 Göttingen minipigs with an average weight of 47.5 +/- 8 kg. In each minipig, one side of the mandible was fractured and one side was left intact. One side of each mandible was plated with a six-hole dynamic multipoint contact plate and the other side with a conventional plate. The plates were applied, either epiosseous or epiperiosteal, with bicortical screws under defined torque. The results demonstrate the advantages of multipoint contact plates over the conventional ones and create the clinical basis for a "bio-logical" plate design that allows callus to grow between the knobs and therefore provide adequate nutritional and vascular supply. The plate's knobbed profile also promotes extraosseous venous drainage without impeding intraosseous fluid flow. This plate is the logical choice for rapid fracture consolidation in the high-grade atrophied mandible.

Aged↗
PubMed1996

[Value of magnified panorama image for diagnosis of fractures of the central mandibular segment].

The accuracy of sonographic imaging of displaced mandibular fractures has been investigated experimentally. Mandibles taken from fresh pig cadavers have been osteotomized and fracture displacement according to the three types of dislocation has been performed. The bony fragments were connected by threads to enable reproducible ranges of displacement. The investigations were performed with 7.5, 10 and 13 MHz linear arrays. Longitudinal and lateral displacements from 1 to 10 mm and axial displacements from 1 degree to 5 degrees were investigated. We could find, that B-mode-sonography is very sensitive to detect the direction of displacement in mandibular fractures, if at least 1 mm of displacement exists. The measurements of the amount of displacement show, that the difference of the sonographic measurements and the real existing displacement depends on the direction of the displacement and the chosen frequency of examination. It is independent from the amount of displacement. The mean error of all examination is less than 0.4 mm. The greatest difference between the real displacement and the measured one is found in axial displacement from 1 degree to 3 degrees. The results show, that B-mode sonography is a reliable method detecting displaced fractures of the mandible and the clinical application of the method can be recommended. The sonographic detection of nondisplaced fractures is a problem which needs further technical development.

Adolescent↗
PubMed1996

[Fractures of the atrophic mandible--a challenge for therapy].

Because treatment of fractures of the atrophic mandible still today presents significant difficulties and treatment modalities remain controversial, 87 of these consecutive fractures which were treated by an uniform method as compression osteosynthesis were evaluated. A new classification of the degree of atrophy which considers the special interest of fracture treatment is introduced. It is based on a metrical measurement of the height of the mandible in the fracture area. Mandibles of 16 to 20 mm height are classified as class I atrophy, those of 11 to 15 mm as class II atrophy, and those with a height of 10 mm or less as extremely atrophic mandibles or class III atrophy. This simple and reliable classification could also be used in future investigations on the results of different treatment modalities in atrophic mandibles. In our series of 87 fractures of the atrophic mandible which were treated by compression osteosynthesis 97% resulted in a solid osseous union without the need of a second surgical intervention. Three major complications occurred: 1 osteomyelitis and 2 non-unions (the latter in one patient with a double fracture of a class III atrophy mandible). To the best of our knowledge this series is the largest of fractures of truly atrophic mandibles treated by one uniform method. Compared to other treatment modalities compression osteosynthesis produced acceptable results and is recommended as the treatment of choice in fractures of the atrophic mandible.

Alveolar Bone Loss↗
PubMed1994

Coronoid process enlargement.

A case is reported of unilateral process enlargement in a 22-year-old man causing limitation of mandibular movements. The radiographic features suggested an osteochondroma. Following coronoidectomy, a definitive diagnosis of coronoid hyperplasia was made.

Adult↗
PubMed1994

[Resorbable synthetics (PDS foils) for bridging extensive orbital wall defects in an animal experiment comparison].

In a long term animal study (min 2 weeks; max 48 weeks) on 6 minipigs, clinical related defects of the medial orbital wall extending in the orbital roof (2.5 cm x 3.5 cm) were created. The defects were bridged by slowly resorbable polydioxanon implants (so called PDS-foils, Ethicon) of different thickness (0.25/0.50 mm) and compared to control defects of identical size. The histological findings reveal: 1. After 29 weeks the resorption of both PDS-implants had been completely finished. Only the morphological intact implants had osteoconductive capabilities. 2. The osseous regeneration of the orbital defects started from the osteotomized margins of the orbital wall. The regenerates were covered by unaffected mucosa. 3. The bony regeneration was supported by the activated periosteal membrane. 4. The resorbed PDS-implants were being replaced by a tight scar tissue, which did not had any adjection to the orbital content. 5. The control defects showed a prolapse of the soft tissue with resulting enophthalmos. 6. According to the material specific characteristics, PDS-foils allow a sufficient bridging of even great and anatomically demanding orbital defects. 7. Notice: The hydrolytical broken down implant material may produce an irritation of the surrounding tissue causing a foreign body granuloma.

Animals↗
PubMed1993

[Perioperative antibiotic prophylaxis in maxillofacial surgery].

In surgical interventions in the maxillofacial area the intraoral approach often is chosen for technical and esthetic reasons. Because of the inevitable contamination of the surgical wounds with the facultative pathogenic mixed flora of the oral cavity, these operations are exposed to an increased risk of postoperative wound infections. Therefore, a perioperative antibiotic prophylaxis is justified. In a prospective, controlled open study in 112 patients the effect of a preoperative one-shot prophylaxis with cefuroxime was compared with that of a short-term prophylaxis for 48 hours. The low rates of postoperative infectious complications in both groups (3.5 resp. 4.5%) verify the efficacy of the perioperative antibiotic prophylaxis in head and neck surgery. For microbiological, practical and economic aspects however, the one-shot-prophylaxis should be preferred.

Adult↗
PubMed1993

Subperiosteal versus epiperiosteal forehead augmentation with hydroxylapatite for aesthetic facial contouring: experimental animal investigation and clinical application.

The difference between periosteal and subperiosteal application of hydroxylapatite (HA) in aesthetic forehead augmentation in the subimplant bed was investigated in six adult Göttingen minipigs. These results were then transferred to clinical application. One exemplary case is described. We found that epiperiosteal augmentation with hydroxylapatite should be performed only if shape and location are stable. Subperiosteal augmentation with hydroxylapatite must be judged critically since HA particles migrate into the subimplant bone.

Adult↗
PubMed1993

The role of the periosteum in osteointegration of hydroxyapatite granules.

The role of the periosteum in the osteointegration of hydroxyapatite (HA) granules was studied in the skull and tibial bone of eight adult Göttingen minipigs. Calcein and tetracycline were used as labeling stains to determine new bone formation. Depending on the condition of the periosteum, three different patterns of osteointegration of HA were found.

Animals↗
PubMed1993

Measurement of the midface symmetry in trauma and reconstructive surgery.

The pre- and intraoperative determination of the midface symmetry during the management of trauma or reconstructive surgery cases may be difficult due to swelling of the covering tissue. To handle these problems, a new apparatus, called "Zygometer", is introduced. This instrument is able to measure the position of the midface bones and enables a comparison with the controlateral side. The results of a study with 250 persons to get standard measurements for symmetry and asymmetry are presented and discussed. Indications and clinical application of the zygometer are demonstrated.

Adult↗
PubMed1993

[An X-ray study of the incidence of asymptomatic hypertrophy of the coronoid process].

Although the coronoid process is not part of the temporomandibular joint, hyperplasia of the coronoid process can effect the mandibular movement as the result of the impingement on the zygomatic arch which is demonstrated in the case of a 22-year-old man. In order to access the prevalence of the asymptomatic enlargement of the coronoid process we carried out an investigation on 2000 panoramic radiographs and found only one case of a 64-year-old man. The very rare coronoid process abnormalities demonstrated on routine plan films should best be demonstrated in computed tomography, appreciating the morphology and the deformity of the surrounding structures.

Adult↗