Search PubMed⌕ Search

Biomedical subjects

H Weerda

Publications and source records attributed to H Weerda.

At least 19 recordsLinked to original sources
PubMed2001

Two-step external ear canal construction in atresia as part of auricular reconstruction.

OBJECTIVES: One of the common complications of atresia surgery is restenosis of the surgically constructed external ear canal. To avoid this complication, a new two-step technique of creating an external ear canal was developed and evaluated. STUDY DESIGN: Prospective clinical evaluation. PATIENTS AND METHODS: Thirty-six patients with third-degree microtia and aural atresia have been treated this way. In the first step, the canal is drilled into the petrous bone, a Silastic cylinder is inserted and wrapped into pieces of cartilage and bone dust. In the second step several months later, the implant is removed and a slightly smaller tube covered with a split thickness skin graft is inserted. RESULTS: Except the first three patients operated with a slightly different technique, none of the following 33 patients showed a severe restenosis. Instead, all had a nice, smooth external ear canal. CONCLUSION: With this two-step technique of creating a new external ear canal in atresia, we could avoid one of the major complications of this kind of surgery. The external ear canal is either necessary for the reconstructed middle ear or it can be used to adapt a (behind or in the ear) hearing aid. By integrating this technique into a three-step concept for auricular reconstruction, the patient does not need any additional operation, and his or her rehabilitation from ear malformation can be enhanced.

Adult↗
PubMed1998

The effect of tissue expansion on the expression of collagen type I and type III mRNA in distinct areas of skin in the dog as an animal model.

To evaluate the transcriptional response of skin to tissue expansion in the dog, the expression of procollagen alpha 1(I) mRNA and procollagen alpha 1(III) mRNA were analyzed by in situ hybridization. This expression was evaluated in distinct skin areas (subepidermal zone, dermis, capsular zone) after 4-85 days of expansion. Within the first 4 days of expansion expression of procollagen alpha 1(I) and alpha 1(III) mRNA was not affected in the subepidermal and dermal zone. Only a slightly elevated level of type III procollagen mRNA was demonstrated in tissue surrounding the implanted silicone expander. After 7 days of expansion an enhanced level of procollagen alpha 1(III) mRNA was observed in the dermis and capsular zone. A slightly enhanced type I collagen mRNA level occurred in all zones of the dermis that was even stronger in the capsular zone after 9 days of expansion. Concurrently, the number of transcriptionally active cells was significantly higher. Return to the basal level of procollagen alpha 1(I) mRNA was attained after 40 days. At this time a significant expression of procollagenase mRNA was observed. Procollagen III mRNA expression reached its basal level on day 85.

Animals↗
PubMed1997

Histopathology of laryngeal changes after long-term chondrosynthesis.

Two patients treated for laryngeal tumors at the University of Lübeck are presented. Both underwent laryngeal reconstructions with plate and screw fixation systems immediately following partial laryngectomies. Recurrent disease was found at 14 and 55 months, respectively, and was subsequently managed by total laryngectomy. The laryngectomy specimens with the plate and screws in situ were evaluated histopathologically, paying special attention to the reaction of local tissue to the implants. Findings showed that the metallic plates were fixed with screws in the bony trabeculae of the laryngeal skeleton. The histological response showed primary wound healing without evidence of sequestration or implant loosening, as often associated with excess mechanical stress. Furthermore, there were no signs of tissue necrosis or widespread chronic inflammation. In both patients, a small discrete area of chronic inflammation and soft tissue fibrosis was noted adjacent to the screw heads. This study supports our previously documented clinical experience that the use of chondrosynthetic techniques is almost complication-free and is an ideal system for performing precise anatomical reconstruction of the laryngeal skeleton.

Aged↗
PubMed1997

[Postoperative pain therapy using on-demand analgesia after external ear reconstruction with rib cartilage harvesting].

BACKGROUND: The individual experience of postoperative pain values considerably. It is the patient who can best evaluate the intensity of pain and the effect of a given analgesic substance. Patient-controlled analgesia (PCA) enables the patient to self-administer an i.v. analgesic bolus by pressing a button of an electronic pump device within a previously set range. If needed. The resection of rib cartilage to be used for ear reconstructions is associated with intense postoperative pain. This could result in unfavorable stress responses such as impaired cough and clearance of lung secretions carrying a greater risk of bronchitis or pneumonia, prolonged mobilization, and complications of wound healing. Therefore, individually adapted pain therapy is of great importance and technically feasible with modern PCA devices. METHOD: Informed and cooperative children aged five years and older and adults without severe health risks are suitable for PCA. Management, handling, monitoring and documentation of the PCA device are discussed. A 24-hour counselling service is maintained for occurring problems. RESULTS: Almost all patients expressed their great satisfaction with the means of pain therapy. Few patients were apprehensive. The initial scepticism of the involved personnel concerning opioid abuse, over-dosage, or technical problems gave way for a support of the PCA once the great satisfaction of the patients in absence of side effects was witnessed. No patient had to be antagonized for respiratory depression. Nausea and vomiting were rare events. CONCLUSION: Patient-controlled analgesia proved to be an excellent answer to postoperative pain after resections of rib cartilage.

Adult↗
PubMed1997

[Orbital and intracranial complications of acute sinusitis in childhood--status of endoscopic paranasal sinus surgery based on case examples].

BACKGROUND: Orbital or endocranial complications of sinusitis are rare clinical syndromes in infancy. METHODS: We retrospectively examined the complications that occurred and the role of functional endoscopic sinus surgery (FES). RESULTS: Most of the complications were caused by acute inflammation of the ethmoid or sphenoid cells with direct extension through dehiscent areas (flat bone) or neurovascular foramina. MRT had the highest sensitivity in detecting acute inflammatory foci. Early elimination of the cause of inflammation by FESS prevents spread of the complication. Advantages of FESS included better orientation and surgical access to the paranasal system of infants. The orbital complications were treated by surgical exploration of the communication pathways by a new endoscopic speculum. CONCLUSION: Early elimination of acute inflammatory foci by FESS prevents spread of infection in complications of paranasal sinusitis in infancy.

Adolescent↗
PubMed1997

High-resolution CT of the temporal bone in dysplasia of the auricle and external auditory canal.

PURPOSE: To determine CT findings in the external, middle, and inner ear of patients with microtia and external auditory canal dysplasia. METHODS: We used high-resolution CT, with multiplanar or axial 1-mm continuous sections, coronal or sagittal reformations, or low-dose spiral acquisitions, to examine 184 temporal bones of children with microtia. RESULTS: In cases of minor microtia, auditory canal stenosis was the most common associated abnormality; in those with major microtia, atresia was predominant. Middle ear malformations depended on the severity of the auricular anomalies. Inner ear changes could also be noted. Ossicle dysplasias occurred in 98% of patients (stapes, 72%), absence of the oval window in 36%, labyrinthine malformations in 13%, closed round window in 6%, facial canal displacement in up to 75%, and aberrations of the vascular canal in 38% of patients with third-grade auricular deformity. CONCLUSION: A variety of external, middle, and, less frequently, inner ear changes were detected in connection with microtia.

Abnormalities, Multiple↗
PubMed1997

[Bone conduction hearing aids with fluid medium].

In patients with chronic otorrhoea or middle ear pathology, traditional hearing aids which depend on air conduction are of little use. In these situations a bone conduction hearing aid is preferable. Such devices by-pass the middle ear cleft and ossicular chain by conducting sound waves through bone to the cochlea. To date, bone conduction hearing aids have transmitted sound via a vibrating transducer applied either to skin (transcutaneous) or to bone (percutaneous). Unfortunately, these hearing aids possess a number of disadvantages, which include: cost, aesthetic appeal, a general anaesthetic for percutaneous aids, and most notably pressure discomfort to the side of the head. To overcome some of these problems a new bone conducting hearing aid is being developed which differs from conventional aids in that sound transmission is through a liquid medium. This has been tentatively named the "Hydro-Hearing Aid" and a prototype is now being tested.

Adult↗
PubMed1996

Experimental and clinical evaluation of laryngeal chondrosynthesis.

The aim of this study was to investigate and develop techniques for stabilization and reconstruction of laryngeal defects with a method similar to osteosynthesis. In an anatomical study, 400 extrusion forces of sutures and various screws (Howmedica) were measured in the thyroid cartilage of fresh cadavers. A new screw was then especially designed for cartilage and a new technique was developed for stabilizing cartilage, using a screw-nut made out of bone. To date, 30 patients have undergone chondrosynthetic reconstruction of the larynx. Measurements of extrusion forces were found to depend on the degree of calcification present in the area of the laryngeal skeleton examined and the type of fixation device used. Good clinical results were achieved in all 30 patients studied and depended on stabilization of the two sides of the thyroid cartilage after thyrotomies, bridging of laryngeal defects and splinting of laryngeal fractures. Besides the increased extrusion forces the advantages of chondrosynthesis lay within the possibilities of axial stabilization and exact bridging of defects with or without implants.

Adolescent↗
PubMed1996

[Ultrasound measurement of skin and cartilage thickness in healthy and reconstructed ears with a 20-MHz ultrasound device].

BACKGROUND: The surgical reconstruction of the external ear according to Weerda is a proven method to correct malformed or amputated auricles. Our goal was to test the usefulness of high-frequency ultrasound in measurement of layer-thickness of auricles. METHOD: Using a 20-MHz B-Mode ultrasonographic method (Dermascan C, adn-Medizintechnik, Hamm, Germany) we measured the thickness of skin and cartilage layers in patients with normal auricles (n = 47) and reconstructed auricles (n = 15) in vivo. RESULTS: The average thickness of the cutis of normal auricles was 0.8 mm, the subcutis and the cartilage layer 0.6 mm thick on average. In reconstructed auricles, the thickness of the cutis averaged 1.0 mm, the subcutis 1.1 mm, and the cartilage layer (to the extent that it could be visualized) 3.0 mm. DISCUSSION: The results demonstrate a good approximation of the thicknesses of the different layers (cutis and subcutaneous tissue) in reconstructed and natural external ears, but the cartilage of the reconstructed auricles is clearly thicker. CONCLUSIONS: The 20-MHz B-Mode ultrasound is suitable for examining the methods of plastic surgery in malformed auricles. Based on the demonstrated results, surgical modifications should be assessed in future.

Adolescent↗
PubMed1996

[High resolution computerized tomography of middle ear abnormalities].

BACKGROUND: The aim of this study was to analyze malformed petrous bones with computed tomography and to develop a radiologic score which can help to judge the indication for operative reconstructions. METHODS: One hundred forty-two petrous bones in 71 patients with unilateral or bilateral microtia, atresia of the external auditory canal, and malformations of the middle ear were evaluated with high-resolution CT. RESULTS: In 97% of patients with severe auricular dysplasia, there was dysplasia of the middle ear ossicles; in 70% the stapes was malformed. In 32% the oval window was occluded, and in 7% the round window. In 75%, the canal of the facial nerve was displaced, and 16% also showed abnormalities of the labyrinth. A close correlation between the malformation of the auricle and of the middle ear was not found. CONCLUSIONS: High-resolution CT is necessary for the evaluation of malformed middle ears. Based on the abnormalities described, we propose a radiologic score for the assessment of malformed petrous bones. This consists of the following criteria: external auditory meatus, pneumatization of the mastoid and of the tympanic space, size of the tympanic space, facial nerve, vessels, malleus and incus, stapes, oval and round window. The graded points of each structure are added up to the score, which might range between 0 and 28. This score can help to judge the indication for reconstruction of the middle ear. In bilateral malformation we suggest a middle ear reconstruction of the better hearing ear if the score is greater than or equal to 15, and in unilateral malformation if it is at least 20. In patients with lower scores, we only suggest hearing aids.

Adolescent↗
PubMed1996

[Diaphanoscopic localization of tear ducts in endonasal dacryocystorhinostomy].

BACKGROUND: Endonasal dacryocystorhinostomy is a well established technique in the surgical treatment of stenosis of the lacrimal system. Due to individual anatomic variations it can be difficult and time consuming to localize the stenosis of the lacrimal system intraoperatively. METHODS AND PATIENTS: To simplify the localization of the lacrimal system, a diaphanoscopic technique that has been used in oral surgery was modified for endonasal dacryocystorhinostomy. A sterile optical fiber is passed through the lacrimal canal from the eye into the lacrimal sac or down to the stenosis. Its light can be detected in the nose and marks the sac or the stenosis. To date we have performed twelve operations with this technique. RESULTS: In our experience, endonasal dacryocystorhinostomy is simplified and accelerated by localizing the lacrimal system with diaphanoscopy. CONCLUSIONS: The diaphanoscopic localization of the lacrimal system during endonasal dacryocystorhinostomy is a slight technical modification that is simple and helpful and could therefore be incorporated into the surgical routine.

Dacryocystorhinostomy↗
PubMed1996

[Osteosynthesis in the mid-face and forehead area].

BACKGROUND: In the beginning of the development of facial osteosynthetic techniques only relatively thick plates were available. Since then various mini- and micro-plating systems were developed for the midfacial and forehead regions. As so many different systems with different sizes are available, it is important to know which systems are appropriate for which indications. Therefore, the aim of this study was to add knowledge to some aspects of the differential indications of different systems for the middle and upper facial regions. METHODS AND PATIENTS: 1. The pull-out forces of seven different mini- and microscrews were measured. 2. The thicknesses of the facial bone were measured at 11 different points in 10 skulls. 3. The clinical experiences of midfacial and upper facial osteosynthesis in 45 patients were summarised. RESULTS: The pull-out forces increase with increasing bone- and screw-thickness and also substantially depend on the design of the screws. Although the bone thicknesses in the mid and upper facial region vary considerably, all investigated regions are suitable for osteosynthesis. In none of our patients any complication occurred that was related to the osteosynthesis. CONCLUSIONS: Microsystems with screw diameters of 0.8 mm (Howmedica) are suited for fractures of the nasoethmoidal complex. Providing the same thickness as the microplates the Panfixsystem (Howmedica) offers a better holding strength especially when using the 1.3 mm screws, and is easier to handle. For stabilising fractures of the zygoma, which might dislocate postoperatively due to the pulling force of the masseteric muscle, we still feel that the miniplating technique with compression is the method of choice.

Adult↗
PubMed1996

[Ultrasound imaging of nasal bone fractures with a 20-MHz ultrasound scanner].

High frequency B-scan ultrasonography is a proven method for the assessment of skin tumors and evaluation of the thickness of skin and cartilage layers. Only limited studies have used sonography to examine bony structures. Our goal was to evaluate the importance of ultrasonography in the diagnosis of nasal fractures. Patients with clinical and/or radiological evidence for such fractures were also examined with 20 MHz B-scan ultrasonography. Results of sonography demonstrated a significant correlation with the nasal fractures present, indicating that additional radiographic examinations are unnecessary in certain cases.

Adult↗