Biomedical subjects
Publications and source records attributed to A R Wittkampf.
A simple method for medical canthal wiring reconstruction with the help of a homolaterally fixed osteosynthesis plate and a metal wire is presented. This avoids transnasal wiring and gives superior control when correcting the position of the lacerated Omedial canthus.
In the cranio-maxillofacial field, computer-aided surgery based on computed tomography (CT) data is becoming more and more important. Navigation systems, which allow the precise intraoperative orientation of surgical instruments, can be used for greater accuracy in determining resection margins of tumours. These techniques support ablative procedures very well, but defect reconstruction still remains a problem. In contrast, computer-aided design (CAD) and computer-aided manufacturing (CAM) systems allow the construction and fabrication of individual templates for bone resection based on coherent numerical 3-D models. The template determines the exact pathway of an oscillating saw so that the planned extent of the resection and, if necessary, also the orientation of the cutting plane are verified. An individual titanium implant is prefabricated with a geometry fitting to that of the template. This implant closes the bone defect so that the contour is reconstructed precisely and individually. This new method was used for the first time for a single-step resection of a meningioma and defect-reconstruction. The tumour which had infiltrated the frontal bone resulting in a protrusion. Fronto-orbital resection and insertion of the titanium implant worked precisely as planned, so that this method offers promising new applications in the field of computer-aided surgery.
PURPOSE: This study radiographically evaluated the stability of mandibular height during a 2-year follow-up after augmentation with prefabricated hydroxylapatite/fibrin glue (HA/FG) implants. PATIENTS AND METHODS: Standardized, lateral oblique cephalometric radiographs were made of 22 patients 6, 12, and 24 months postoperatively and analyzed with a newly developed, computerized image analysis technique. RESULTS: The average height of the HA/FG implants after augmentation was 9.45 mm. Average loss of total height of the augmented mandibles was 2.31 mm after 6 months, 2.90 mm after 12 months, and 3.93 mm after 24 months. Reduction of HA/FG implant height alone was 0.62 mm after 6 months, 1.24 mm after 12 months, and 2.03 mm after 24 months. Reduction occurred mainly during the first 6-month evaluation period and was probably primarily caused by adaptation of the implant to the surface of the mandible. An inferior compression of the implant or resorption of the alveolar crest and underlying basilar bone are possible reasons for loss of total mandibular height. CONCLUSION: The results indicate that prefabricated HA/FG implants used for augmentation of edentulous mandibles show little reduction in height, but are not completely stable during a 2-year evaluation period.
With the aid of axial CT scanning a polyurethane or resin copy of bony tissue of the craniofacial region of interest can be manufactured. 3-dimensional models are used in planning of osteotomies of the midface and forehead, where complex bone transpositions are to be performed, and in manufacturing complex implants. Different preoperative steps in several patients are demonstrated and the postoperative results are shown. Patient A was a 9-year-old girl who had radiotherapy as a baby for retinoblastoma which destroyed a large part of her face. In patient B, a 46-year-old woman, the whole zygomatic bone and three-quarters of the floor of the orbit were among other things resected for a low-grade osteosarcoma. Patient C had Goldenhar's syndrome (oculoauriculovertebral dysplasia). In all 3 patients reconstructive surgery was prepared with 3-dimensional cut models.
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A study was carried out on mechanical stress at the resection site in mandibles undergoing segmental resections. A computer simulation model was used to study particularly the effect of various radii of the posterior resection corners and the effect of elimination of muscle action. It was found that an enlarged radius of the resection corner in conjunction with coronoid process resection on the ipsilateral side offers the best condition to prevent fracture of the mandible.
The tension strength of mandibular halves of beagle dogs, with two different types of segmental resections, was studied. It was found that the radius of the posterior resection corner is of utmost importance in reducing the risk of mandibular fractures.
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A review of 35 patients in whom a subperiosteal tissue expander was used before reconstruction of the alveolar ridge with hydroxylapatite granules is presented. The mean increase in mandibular height was 8.4 mm as measured on true lateral cephalometric radiographs. Secondary preprosthetic surgery was necessary in two cases.
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An easy, economic and safe method is described for handling HA-granules in recontouring procedures of the alveolar ridge with the help of fibrin glue as a cement.
Experience in handling particulate HA granules in the augmentation of the atrophic mandible is described. Different methods like the use of fibrin glue and the subperiosteal tissue expander in relation with the type of atrophy are discussed.
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A retrospective study on 15 patients with myxomas of the jaws was carried out. The series consisted of 3 males and 12 females. The mean age was 26 years. The maxilla was involved in 4 cases whereas the tumour was situated in the mandible in 11 cases. Of the 9 patients who underwent conservative treatment, one exhibited recurrent tumour. Six patients were treated by resection including uninvolved adjacent tissue; none of them has so far exhibited recurrence. These results indicate that carefully performed conservative treatment for myxomas is justified in some instances. Histologically, myxomas of the jaw exhibit mitotic activity in the majority of cases which indicates a distinct proliferative activity. Myxomatous degeneration in neurofibromas may mimic myxoma. Therefore the present cases were compared with 2 cases of intramandibular neurofibroma. It is concluded that differences in nuclear morphology are sufficient to distinguish between both neoplasms.
A series of 20 patients with extra-nodal non-Hodgkin's lymphoma (ENHL) of the oral cavity was analysed with the emphasis on histopathological variability and prognostic factors. The current diagnostic schemes as devised for nodal NHL proved also to be useful in diagnosing ENHL in the oral cavity. With respect to histopathology, intra-oral ENHL differs from nodal NHL in a lower incidence of nodular growth pattern and a relative predominance of the lymphoma sub-type with large vesicular indented nuclei. These are features, however, that are shared with ENHL in other body sites and thus are not unique to the oral location. Another salient histological feature was the presence of proliferating bizarre spindle cells with formation of whorling bundles of reticulin, thus creating a pseudosarcomatous growth pattern in some cases. The clinical stage proved to be the main discriminating factor between those who survived and those who died of their lymphoma. Of the patients who were in stage IE on admission, 70% survived as opposed to only 20% of those who were in stage II or IV. A better prognosis for cases with soft tissue involvement as opposed to intraosseous lymphoma is probably due to a consistently lower clinical stage in the former group. The prognostic value of the clinical stage emphasizes the importance of adequate clinical staging procedures.
In this case report a patient with multiple duplications in the cervical spine, skull-base and oral cavity is described and a discussion on the possible origin of the duplications is presented.
Two patients with discolouration fo skin grafts after head and neck surgery, were treated with dermatography, a refined method of tattooing, and with intra-cicatricial keloidectomy, of which the results are described.