Biomedical subjects
J Raveh
Publications and source records attributed to J Raveh.
Titanium-coated hollow screw and reconstruction plate system for bridging of lower jaw defects: biomechanical aspects.
The biomechanical and design principles of the titanium hollow screw and reconstruction plate (THRP) system are described. Physiologically advantageous load transmission, a biocompatible implant material with sufficient strength and a surface structure favorable to biological stabilization are discussed. The design of the fixation between the cross-split screwhead and the plate hole gives a rigid and stable plate fixation even without contact between plate underside and bone. Blood perfusion and bone strength will therefore not be affected. Full functional loading with only 2-3 fixation screws for each plate end is possible. Further technical advantages of the THRP system are the possibility of lingual plate application and integration of a three-dimensional adjustable condylar prothesis.
The surgical one-stage management of combined cranio-maxillo-facial and frontobasal fractures. Advantages of the subcranial approach in 374 cases.
The aim of this paper is to emphasize the advantages of a one-stage, step by step repair of facial skeletal injuries as well as the dural tears and lesions of the anterior fossa, by one and the same team. The methods described permit optimal reduction of the pseudohypertelorism and major displacements in severe combined craniofacial injuries. The simultaneous subcranial exposure of the entire basal region of the anterior fossa obviates the intracranial approach or frontal lobe retraction thus making early stage surgical management feasible. The surgical treatment of these injuries as a single entity, as well as further modifications reduce complications such as recurrent CSF leakage, anosmia, mucocoele or secondary operations for inadequate fracture reduction. The significance of primary meticulous reconstruction of the combined cranial vault and midface fractures for the achievement of normal physiological function of the various systems is particularly highlighted.
Advantages of an additional subcranial approach in the correction of craniofacial deformities.
The subject of this paper are the advantages conferred by the subcranial and extracranial approach for the performance of fronto-orbital osteotomy and advancement. In contrast to the usual intracranial approach the resection of the ethmoidal and medial aspect of the orbital roof can be achieved by the subcranial and transethmoidal approach, thus avoiding any damage to the olfactory filaments. The resulting subcranial compartment, after radical resection of the ethmoidal cells, enables optimal visualization of the optic nerve and decompression from this access. Frontal lobe retraction is only necessary at the lateral fronto-temporal region in order to complete the lateral osteotomy. Thus the morbidity rate related to the intracranial procedure can be reduced. Further advantages are the watertight repair of the skull base with fascia lata and the drainage of the intercranial region avoiding the postoperative development of the Orbital Apex Syndrome.
Mandibular reconstruction with the titanium hollow screw reconstruction plate (THORP) system: evaluation of 62 cases.
The titanium hollow screw reconstruction plate (THORP) system for reconstruction of lower jaw defects provides a functional stable fixation and is used as a long-term or permanent implant in tumor surgery and in traumatology. The rigid fixation of the head of the screw to the plate, avoiding unphysiologic loads to the bone underneath the plate, and the titanium plasma-coated perforated hollow screws, enabling the development of direct bone-titanium contact as well as the ingrowth of bone into the lumen and perforations, are the major advantages of this system compared to conventional systems. The different surgical methods, such as preservation of the condylar process with only two screws, intraoperative freely adjustable condylar prosthesis, lingual application of the plate, and primary bone transplantation, are described. The evaluation of 62 patients reconstructed with the THORP system between 1981 and 1986 revealed no plate loosening, even in irradiated bone, and showed satisfactory aesthetic and functional results.
[Indications for surgical management of condylar fractures].
Twenty-nine patients with 249 fractures of the condylar process were treated by surgery which was reserved for fractures with medial dislocation of the condylar head out of the articular fossa. The fractures were exposed from a preauricular incision. Interosseous wires were not used: intermaxillary fixation for 10 days and functional treatment for another 3 weeks were the standard post-operative treatment. The operative technique and the results are described.
[Craniofacial surgery. Advantages of subcranial procedures in craniofacial surgery].
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Fixation of bone fragments with BIOCEM. First observations on humans.
BIOCEM is a recently developed material that consists of bisphenol-a-glycidyl methacrylate ("epoxide methacrylate") as the organic matrix and pentacalcium hydroxide triphosphate ("tricalcium phosphate") with or without bioceramic A2 as the filling particles. Previous animal experimentation has demonstrated that BIOCEM can establish and maintain direct contact with bone without compromising tissue vitality. Rather, it favors with time the ingrowth of, and coverage by, newly formed bone, thus creating interdigitations and strong fixation of the implant. This novel technique has now, for the first time, successfully been applied in humans, ie, for the fixation of frontal sinuses. Clinical, radiological, and histological findings are briefly reported, and it is also shown that the frontal sinus mucosa had recovered at the inside of the lesions filled with BIOCEM.
Plate osteosynthesis of 367 mandibular fractures. The unrestricted indication for the intraoral approach.
Experience in the management of 916 fractures of the mandible stimulated us to develop new methods and surgical techniques for functionally-stable intraoral internal plate osteosynthesis. The development of a fixation bar which is adapted to the alveolar process of the fractured mandible enables a compression of this area prior to the plate osteosynthesis. This procedure facilitates the plate application from the intraoral approach so that in 358 cases all types of fractures of the body, angle and ascending ramus can be reduced using this access, and not only the selected favourable cases. A new plate and screws of our own design have been successfully used in cases with comminuted multifragmentary and defect fractures. The rigid fixation of the head of the screws to the plate produces an optimal functional stability compared with conventional systems. The combination of the advantages of an external fixation device and those of stable internal osteosynthesis produces a long term functional stability even in cases with extensive defects where delayed consolidation is to be expected; tilting and loosening of the screws or resorption of the compact bone underneath the plate do not occur. Thus the extraoral approach and visible skin incisions can be avoided. This procedure is time sparing and less traumatic to the soft tissues compared with the extraoral approach. The extremely low complication rate in 358 fractures managed by plate osteosynthesis using the intraoral approach confirms the efficiency of this method.
[Biocements as fixation and bridging materials in bones].
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[Sagittal splitting: assessment of results after using the authors' own method in 103 cases].
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[Advantages of the titanium plasma-coated half- and full-core reconstruction plate system (THORP) for the bridging of mandibular defects].
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Surgical procedures for reconstruction of the lower jaw using the titanium-coated hollow-screw reconstruction plate system: bridging of defects.
The various advantages rendered by the system described enable primary as well as long-term functional stability even in cases in which conventional systems would be insufficient. The evaluation of 49 cases managed in Bern and Sweden confirm the efficiency of this reconstruction system.
[New aspects of craniofacial surgery].
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[Craniofacial surgery: advantages of radical transethmoidal ethmoid resection].
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The lingual application of a reconstruction plate: a new method in bridging lower jaw defects.
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[Titanium-coated hollow screw and reconstruction plate system for the bridging of jaw defects. II. Possible reconstruction variants with the THRP system].
The advantages and special features of the THRP-system enabled us to develop new operative techniques. The combination of the advantages of external fixation devices and those of the internal osteosynthesis has proved to be decisive in order to obtain good results. The clinical results in 30 patients confirm the recently published findings from animal studies. Histological examination of human specimens comparing 2 types of screws developed by us are discussed.
[Preservation of temporomandibular joint continuity and application of full-core titanium screws in the bridging of lower jaw defects].
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