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1.
Nasal reconstruction presents a significant challenge to the facial plastic surgeon. Reestablishment of the desired aesthetic nasal contour and restoration of respiratory function are the dual goals of this endeavor. While autologous cartilage or bone is considered optimal grafting material, the supply is often limited and harvesting entails additional morbidity. Many synthetic materials have been introduced for use in nasal reconstruction, but high infection and extrusion rates have left most surgeons dissatisfied with conventional implants. Porous polyethylene (Medpor) implants were used for nasal reconstruction in 187 patients; 66 (35.3%) patients underwent primary rhinoplasty, while revision surgery was performed in 121 (64.7%) patients. Most patients required multiple implants, including columella struts, plumper grafts, dorsal tip implants, and nasal valve battens. Postoperative follow-up ranged from 6 months to 3.5 years. Complications occurred in five (2.6%) patients. Three early and two delayed infections necessitated implant removal in five patients, all of whom had compromised skin-soft tissue envelopes secondary to heavy smoking, cocaine abuse, or prior surgery. One case of an overly augmented nasal dorsum and tip required implant removal, reduction, and reinsertion. All implants were easily removed. No other complications including implant extrusion or skin erosion have been noted. Porous polyethylene (Medpor) implants allow for fibrovascular ingrowth, which lends stability to the implant. Porous polyethylene implants are well tolerated and provide an ideal material for nasal reconstruction.  相似文献   

2.
OBJECTIVE: To determine the usefulness of porous high-density polyethylene implants (Medpor) in a variety of facial skeletal deformities and subcutaneous defects, excluding those associated with acute maxillofacial trauma. DESIGN: Case series. SETTING: Academic tertiary care referral center in Baltimore, Md. PATIENTS: Thirty-four patients (age range, 20-74 years) with facial deformities requiring skeletal defect reconstruction or augmentation (38 cases), treated between January 1, 1992, and January 1, 1997. Follow-up ranged from 6 months to 40 months. MAIN OUTCOME MEASURES: Age, type and origin of the deformity treated, type of treatment, and complications. RESULTS: Types of deformities and defects treated include 7 patients with orbital defects (secondary traumatic or oncologic deformities), 8 with temporal fossa defects, 8 with frontocranial defects, 4 with maxillary or malar defects, 7 with calvarial bone graft donor site defects, 2 with microtia, and 2 with chin deficiency. Forty implants were placed. Complications included implant exposure in 4 patients and inappropriate augmentation in 1 patient (chin implantation). CONCLUSIONS: High-density polyethylene implants offer an excellent alternative to autogenous and other alloplastic materials in reconstruction of many facial defects and deformities. Advantages include its versatility and relatively ideal pore size that allows for excellent soft tissue ingrowth and coverage. Disadvantages include its rigid nature and difficulty in contouring to the surface of complex skeletal structures.  相似文献   

3.
OBJECTIVE: The results of the first cohort of 60 cavity reconstructions with hydroxyapatite with a minimum follow-up period of 15 years were studied. STUDY DESIGN: The study design was a retrospective study. PATIENTS: A total of 60 patients had a follow-up period of >15 years. In four patients, not all data were available. Therefore, 56 patients were included in the study. They had a combination of cavity problems and hearing loss. INTERVENTION: The ear canal was reconstructed with a canal wall prosthesis of porous hydroxyapatite. The ossicular chain was reconstructed with an incus or incus-stapes prosthesis of dense hydroxyapatite. RESULTS: After 15 years, 42 patients (75%) had an intact reconstructed ear canal. The main problem for failure was the recurrent purulent middle ear infection and not cholesteatoma. The histology of the retrieved canal wall showed a good remodeling in living bone tissue. After 15 years, 34 patients had a normal ear canal and an ossicular chain. Of these patients, 7.05% had an air-bone gap closure within 20 dB. CONCLUSIONS: Long-term results of cavity reconstruction with hydroxyapatite are possible. The main problem is recurrent mucosal disease of the new middle ear-mastoid cleft.  相似文献   

4.
Twenty-nine infant rabbits from four litters were randomly assigned to three groups. No surgery was performed on left eyes. All right eyes were enucleated. Group 1, the control group, had no right-socket reconstruction. Group 2 had reconstruction using free-fat and dermis grafts. Group 3 had reconstruction using porous polyethylene implants. On attaining adult size, rabbits were killed, decapitated, and prepared for measurements. Orbital volume measurements were performed twice and orbital entrance areas were determined once. No significant differences were noted between first and second measurements of orbital volumes. Right orbital volumes were significantly smaller than left orbits in all groups except for the second measurement of the polyethylene implant group. Right orbital entrance areas were significantly smaller than left areas in the control and the free-fat and dermis graft groups. Right orbital entrance areas of the polyethylene group were not significantly smaller than the corresponding left orbital entrance areas. The use of free-fat and dermis grafts for orbital reconstruction in anophthalmic infant rabbits did not significantly stimulate orbital bone growth. In one trial, the polyethylene implant group displayed right orbital volumes and orbital entrance areas that were not significantly smaller than controls.  相似文献   

5.
BACKGROUND: The alar region is one of the most difficult areas of the face to reconstruct. Up until now, various methods have been demonstrated for achieving the best possible results in terms of cosmetic appearance and function. This report deals with a combination of a random pattern flap and a free composite graft, carried out in two stages. OBJECTIVE: In order to reconstruct the alar region, an island advancement flap as well as a composite graft from the contralateral ear were used. METHODS: The defect in the cheek-upper lip region was closed using an island advancement flap. In a second operation 2 weeks later, the reconstruction of the alar region was attempted using a composite graft from the right ear. RESULTS: The reconstruction of the contour of the wing of the nose succeeded in a satisfactory manner. There are no functional restrictions on nose breathing. CONCLUSIONS: The combination of an island advancement flap with a composite graft from the ear for the reconstruction of the alar region is essentially a less invasive operation that can be carried out under local anaesthesia and that represents an addition to the previously stated methods.  相似文献   

6.
基于对已有三维人耳重建工作和形变模型理论的研究,充分结合人耳自身的结构特征,提出了一种新的三维人耳重建方法——基于人耳形变模型的方法.首先使用中垂线法完成了外耳轮廓特征点的定位;提出分级三角网格法,解决了样本耳基于生理特征的稠密对应问题;再借鉴广义普鲁克分析的思想,在三维空间内实现了精确全自动的三维人耳形状对齐;最后训练得到了三维人耳形变模型.所提方法只需一幅二维图像,即可获得足够稠密的三维人耳模型.在UND三维人耳数据库和USTB三维重建人耳数据库上的大量实验证明所提方法的有效性和优越性.   相似文献   

7.
This paper reports our experience in total reconstruction of the ear using allogeneic auricular cartilage framework in 8 patients. The allogeneic auricular cartilage framework has natural appearance, and no carving or fabrication is needed. The cartilage treated with glutaraldehyde firmly adhered to its surrounding tissue of the host in a short time. Good results were observed in 6-month to 2-year follow-up, and no complications such as rejection, distortion and absorption occurred.  相似文献   

8.
By means of modern 3D-visualization systems it is possible to render detailed reconstructions of very small morphological structures such as the inner ear. Aim of the present study was to demonstrate the imaging quality of a new 3D-segmentation program developed in the University of Hamburg. The investigation was carried out on a high-resolution MR-tomography of the author's labyrinth and facial nerve. The images were obtained with a fast-field-echo technique using a surface coil. 32 axial slices of 1.0 mm thickness were used for reconstruction. Thus it was possible to completely visualize cochlea, semicircular canals and facial nerve. Especially the filiform substructures of the inner ear could reliably be reconstructed. So the content of information of the MR-investigation could be increased by the 3D-technique applied.  相似文献   

9.
Osteolysis can occur around loose, as well as well fixed, cemented or cementless acetabular components in total hip arthroplasty. Histologic studies of tissues biopsied from osteolytic regions suggest an adverse foreign body response to polyethylene and other particulate debris from prosthetic materials. Phagocytosis of these particles by macrophages and giant cells stimulate the production of proteolytic enzymes and inflammatory mediators, all leading to tissue destruction. The importance of polyethylene wear debris is now fully appreciated, and it is clear that this is the major contributor to particulate debris. The authors strongly recommend the avoidance of 32 mm femoral heads, thin acetabular component liners, titanium heads, and acetabular screws when absolutely necessary. We strongly advise 26 mm to 28 mm femoral heads, polyethylene thickness of at least 8 mm, precise liner shell contact, rigid fixation of the acetabular metal shell, intimate bone-acetabular shell contact, and circumferential porous coating of femoral components to decrease the amount of and migration potential of polyethylene debris (Table). Based on our current knowledge, these measures will minimize the problem of acetabular osteolysis.  相似文献   

10.
PURPOSE: To optimise three-dimensional spiral CT of the tracheobronchial tree using adequate acquisition and reconstruction parameters for spiral CT of the chest. MATERIAL AND METHODS: Qualitative and quantitative assessment of different 3 D reconstructions of two test objects of the tracheobronchial tree depending on section thickness, reconstruction interval, pitch, and reconstruction algorithm used in spiral CT (Siemens, Somatom plus S) of the chest. The frequency of volume and stairstep artifacts was evaluated. The 3 D reconstructions were generated using a seeded VOI-technique (Allegro, ISG). RESULTS: Reduction of artifacts was achieved by decreasing section thickness. Increasing overlap of source images, lowering the pitch factor, and application of the reconstruction algorithm "slim". Section thickness was the single most important factor which was mainly responsible for the occurrence of volume artifacts. Stairstep artifacts were primarily influenced by the reconstruction interval. CONCLUSION: Spiral CT with a section thickness > 4 mm is not adequate for 3 D reconstructions of the tracheobronchial tree. Overlapping source images with a pitch of 1 and the reconstruction algorithm "slim" can be recommended to reduce artifacts.  相似文献   

11.
Stahl's ear is a congenital malformation of the auricle, which is uncommon in non-Oriental societies. A number of different treatment modalities have been suggested, many of which yield unpredictable results. We review current treatment modalities from the English literature and describe a novel, simple surgical method of repair. First, a helical rim incision is made to expose the abnormal third crus and upper pole of the ear. The third crus is excised as a narrow wedge of cartilage and posterior skin, and the defect is closed primarily. The free third crus cartilage is then grafted onto the scaphal cartilage in an anatomically correct position to form a superior crus. The anterior skin flap is redraped and bolstered over this graft. Only a very small scar on the helical rim remains visible anteriorly.  相似文献   

12.
To determine the three-dimensional (3-D) shape of a live embryo is a technically challenging task. We show that reconstructions of live embryos can be done by collecting images from different viewing angles using a robotic macroscope, establishing point correspondences between these views by block matching, and using a new 3-D reconstruction algorithm that accommodates camera positioning errors. The algorithm assumes that the images are orthographic projections of the object and that the camera scaling factors are known. Point positions and camera errors are found simultaneously. Reconstructions of test objects and embryos show that meaningful reconstructions are possible only when camera positioning and alignment errors are accommodated since these errors can be substantial. Reconstructions of early-stage axolotl embryos were made from sets of 33 images. In a typical reconstruction, 781 points, each visible in at least three different views, were used to form 1511 triangles to represent the embryo surface. The resulting reconstruction had a mean radius of error of 0.27 pixels (1.1 microns). Mathematical properties of the reconstruction algorithm are identified and discussed.  相似文献   

13.
Prefabricated free flaps using an expansion technique were used for four reconstructive cases, including two leg reconstructions and two facial reconstructions. In this series, the prefabricated free flaps created by using the expander were classified into two types: the expanded flap based on the conventional vascular pedicle, which is called the expanded flap with primary vascularization; and the expanded flap based on the vascular pedicle in the carrier, which is called the expanded flap with secondary vascularization. The expanded flap with primary vascularization that is created in the trunk has a good indication for leg reconstruction, because it provides an wide and thin flap with minimal donor site morbidity. The expanded flap with secondary vascularization created in the pectoral region has a good indication for facial reconstruction, because it provides good color and texture matches. Although there are some disadvantages in the tissue expansion technique, the prefabricated free flaps using the expander are very effective in facial and leg reconstruction.  相似文献   

14.
Detailed morphometric knowledge of the microvascular network is needed for studies relating structure to haemodynamic function in organs like the lung. Clinical volumetric CT is limited to millimetre-order spatial resolution. Since evidence suggests that small arterioles (50 to 300 micrometres) dominate pulmonary haemodynamics, we built a micro-CT scanner, capable of imaging excised lungs in 3D with 100 microm resolution, for basic physiology research. The scanner incorporates a micro-focal (3 microm) x-ray source, an xyz theta stage and a CCD-coupled image intensifier detector. We imaged phantoms and contrast-enhanced rat lungs, reconstructing the data with either the Feldkamp or the circle-and-line cone-beam reconstruction algorithm. We present reconstructions using 180 views over 360 degrees for the circular trajectory, augmented with views from a linear scan for the circle-and-line algorithm. Especially for platelike features perpendicular to the rotation axis and remote from the midplane, the circle-and-line algorithm produces superior reconstructions compared with Feldkamp's algorithm. We conclude that the use of nonplanar source trajectories to perform micro-CT on contrast-enhanced, excised lungs can provide data useful for morphometric analysis of vascular trees, currently down to the 130 microm level.  相似文献   

15.
Lengthening of the mandible by gradual distraction and ear reconstruction using tissue expanders were performed on nine young patients (6-11 years old) with unilateral hemifacial microsomia. The technique holds promise for reconstruction of ear and mandible at the same time. This is essentially a pilot clinical project. A late follow-up of these patients is necessary.  相似文献   

16.
Thirty-five consecutive anterior cruciate ligament (ACL) reconstructions were performed in an ambulatory surgical unit using a bone-patellar tendon-bone autograft. Patients were evaluated postoperatively to determine the amount of pain medication used, the readmission rate, postoperative complications, and cost. Outpatient ACL reconstruction led to a savings of $4700 compared with the cost of performing the same procedure in a hospital operating room with an overnight admission. This study demonstrates that outpatient ACL reconstruction, using local analgesia intraoperatively and oral narcotic pain medication postoperatively, is a safe and cost-effective procedure with minimal to no morbidity.  相似文献   

17.
We present a method for combining single axis tomography and serial sectioning techniques to derive a three-dimensional reconstruction of large structures at electron microscopic resolution. This serial-tomography method allows the use of sufficiently thin sections to achieve adequate resolution with electron tomography, yet enables the generation of large reconstructions with considerably fewer sections than would be required using a serial thin section reconstruction technique. Serial thick sections (1-2 microns) are cut through the structure of interest, tomographic volume reconstructions are obtained for each section from a single axis tilt series, and the resulting series of volumes are then aligned and combined to form a single large volume. The serial-tomography method is illustrated with several samples, including red blood cells, the Golgi apparatus, and a spiny dendrite of a cortical pyramidal neuron. In some of these samples, the reconstruction is compared to correlated light microscopic views. The resulting large volume reconstructions appear to represent accurately the size and shape of objects such as red blood cells and spiny dendrites. The continuity of complex, tortuous structures such as the Golgi apparatus is also maintained across serial volumes. These examples demonstrate that it is possible to align and link a series of tomographic volumes accurately and that serial-tomography is a useful method for reconstructing relatively large structures without resorting to large numbers of serial thin sections.  相似文献   

18.
Free TRAM flap transfer is now routinely offered to patients requiring breast reconstruction. This study compares results of conventional superior-pedicled TRAM flaps and free TRAM flaps in bilateral breast reconstructions. A total of 92 breasts were reconstructed in 46 patients. Eighteen patients had free TRAM flap reconstructions, and 28 patients were reconstructed with conventional TRAM flaps. Comparison of average operative blood loss and average operative time for the two techniques showed blood loss of 575 cc and an operative time of 9.6 hours for the free TRAM reconstructions and a blood loss of 313 cc and an operative time of 6.6 hours for the conventional TRAM reconstructions. For free TRAM flap reconstructions, both blood loss and operative time decreased significantly between the first and second group of nine patients: from 819 to 360 cc of blood loss and from 10.5 to 8.9 hours of operative time. Partial flap loss (skin and fat necrosis) and fat necrosis only occurred in 13 and 7 percent, respectively, of conventional TRAM flaps, but neither occurred in free TRAM flaps. However, early in the series, three free flaps were lost in two patients, requiring implant placement. Bilateral breast reconstruction using the free TRAM flap may offer a lower complication rate than the conventional TRAM flap by virtue of improved blood supply and less abdominal wall disruption. Surgeons, however, are forewarned that this procedure has a steep learning curve, and surgeons lacking microsurgical expertise may be better served by the conventional TRAM flap.  相似文献   

19.
This retrospective study analyzed 202 toe-to-hand transplants performed over the last 20 years at the Davies Medical Center, San Francisco (USA). The overall success rate was 97%. Toe transplants for finger reconstruction yielded optimal functional and cosmetic results due to their anatomical similarity to fingers. The great toe was preferably used for thumb reconstruction, whereas the other toes were used for reconstruction of the long fingers. Early reconstructions, multiple simultaneous toe transplants, and interventions combining toe transplantation with free flaps seemed to be advantageous because of shorter rehabilitation and comparable results.  相似文献   

20.
1. We investigated the effect of unilateral vestibular stimulation on histamine release from the anterior hypothalamic area of urethan-anesthetized rats in vivo, using a brain microdialysis method coupled with high-performance liquid chromatography fluorometry. 2. The histamine release was increased to approximately 180% of the basal release by the electrical stimulation of the inner ear with 1 Hz, 500 microA, and 200 ms for 20 min. This effect was dependent on the current intensity. 3. Activation of the unilateral horizontal semicircular canal by middle ear irrigation for 15 min with 45 degrees C water increased the histamine release to approximately 200% of the basal release. 4. Irrigation of the middle ear with ice water for 15 min increased the histamine release to approximately 190% of the basal release. 5. The histamine release was not changed by the irrigation of the middle ear with 37 degrees C water and the irrigation of the auricle with ice water, which suggests that neither somatosensory stimulation to the middle ear nor nonspecific cold stress affects the histamine release. 6. All these findings suggest that the sensory mismatch signals induced by caloric stimulation and unilateral electrical vestibular stimulation activate the histaminergic neuron system in the brain.  相似文献   

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