Biomedical subjects
Publications and source records attributed to F Sutter.
The development of dental implants has led to an expansion of indications and to perfection of implantation methods and implant systems. Angulation problems due to anatomic limitations, however, still remain. The indications for the use of angled Bonefit I.T.I. implants are described.
The treatment of zygomatic fractures varies among surgeons, and the cosmetic and functional results are frequently less than optimal. A treatment guideline based on a simple classification of zygomatic fractures is presented. The emphasis is placed on the indications for closed and open reduction, consistent methods of three-dimensional alignment and fixation, and the management of concomitant infraorbital rim and orbital floor fractures. Postoperative results with regard to infraorbital nerve and maxillary sinus dysfunction, malar asymmetry, and orbital complications in the treatment of 1,025 consecutive zygomatic fractures are presented.
The issues of bone necrosis and implant bed congruency are both central to the success or failure of endosseous dental implants to achieve osseointegration. Use of internally irrigated drilling instruments has been postulated to minimize bone necrosis. The ability of the cutting instruments to produce a smooth, congruent implant bed and retain fine bone structures is also critical to achieving primary integration. In the experiment conducted, the use of internally cooled instruments reduced the likelihood of thermal bone damage, particularly when trephine mills were used. Trephine mills were able to retain the fine bone structures of the walls of the implant bed site. No visible degradation occurred from multiple uses of the instruments.
A 10-year experience with surgical treatment of 813 zygomalateral orbital complex fractures is reviewed. Regardless of the type or severity of the fracture pattern, concomitant fractures of the orbital floor and rim were approached exclusively through the transconjunctival approach without a lateral canthotomy. The advantages of this approach compared with the subciliary access are the avoidance of a visible scar and markedly reduced incidence of postoperative lower eyelid complications such as ectropion and edema. Implants of lyophilized dura or cartilage and autogenous bone were used to reconstruct orbital floor defects. Malar asymmetry is a frequent complication of zygoma fractures resulting from inadequate three-dimensional reduction. Methods for accurate reduction and stabilization, indications for closed and open reduction, and management of the fractured infraorbital rim are emphasized. The indications for miniplates vs wire ligatures for the infraorbital rim are discussed. Long-term follow up and evaluation of the results with regard to the fracture pattern, complications, maxillary sinus dysfunction, and facial and orbital symmetry are presented.
The explantation technique for the ITI F-type and Bonefit implant system is described. Although implant survival rates are high, the risk of failure must be considered. In some cases implants will have to be removed for reasons other than failure of the implant itself.
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This investigation was planned to detect the ability of radiated bone to integrate with dental implants and to study the load-bearing capacity of these implants. In five beagle dogs, the premolars were extracted, after which one side of the mandible was radiated with 40 Gy. Three months later, two hollow-cylinder implants were placed on each side of the mandible. After a three-month period of osseo-integration, bridges were constructed on the implants, and they were loaded for six months. Both clinical and x-ray examinations showed that all implants had integrated well and bore load without change in their host sites for a six-month period, at which time the dogs were killed.
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The THORP system is designed for bridging mandibular defects and for internal osteosynthesis of mandibular fractures. The major aspects and advantages of the THORP system compared with the conventional reconstruction plates and screws are: 1. The rigid fixation of the head of the screw to the plate, thus avoiding unphysiological loads to the bone underneath the plate. 2. The titanium-plasma coated and perforated hollow screws enable the development of direct bone-titanium contact at the area of the thread as well as the ingrowth of bone into the lumen and perforations. Further advantages are the preservation of small fragments such as the condylar process with only two screws and the stable fixation of bone transplants. The specially designed freely adjustable condylar prosthesis guarantees a correct guidance and function of the lower jaw. The fixation of this system to the lingual aspect of the jaw is particularly significant avoiding decubitus and perforation of the skin in the chin area. The results and the complications of 141 reconstructions of the lower jaw are discussed.
The surgical treatment of 26 patients with ankylosis of the temporomandibular joint, as well as various methods and materials used for functional restoration are described. The significance of radical removal of the ankylotic bone, as well as the advantages of the interpositioning of the lyophilized cartilage, are emphasized.
The subject of this paper is the evaluation of the advantages pertaining to the THORP (titanium hollow screw reconstruction plate) condylar prosthesis for reconstruction after hemimandibulectomy and exarticulation. The THORP condylar prosthesis is three-dimensionally adjustable, enabling the intraoperative meticulous functional adaptation of the condyle. Various designs of the condyle make it possible to achieve optimal congruency between the articular fossa and condyle. The anchorage of the prosthesis to the stump of the mandible is achieved with perforated hollow-screws rigidly fixed to the plate, thus producing optimal functional stability. The long-term follow-up of eleven cases, reconstructed with this system, confirmed the correct guidance and functional efficiency of this type of condylar prosthesis.
In this paper the surgical management of TMJ dysfunction-ankylosis and arthropathies-is described. The surgical techniques and the necessity of wide exposure are pointed out. Only thus are correct reshaping of the condyle, repair of the disc and radical resection of ankylotic bone tissue possible. The indication for prosthetic substitution to be interpositioned in cases with discal atrophy and perforation is discussed. There were no cases of facial paresis and no recurrence of ankylosis. The results, in regard to the functional aspects, confirm the efficiency of the methods described.
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In severe craniofacial injuries, the involvement of the skull base with concomitant major dural tears is significantly high. Our methods and treatment plan are controversial compared with the conventional procedure: primary urgent neurosurgical exploration and repair with deferral of maxillofacial reconstruction. To avoid the disadvantages of the transfrontal intracranial management of the skull base, we modified the transethmoidal approach so as to enable the subcranial exposure of all the anterior fossa planes, including the sellar-sphenoidal region. The advantages rendered by this method are the feasibility of an early one-stage craniofacial reconstruction and avoiding retraction of the frontal lobes and damage to the olfactory filaments. The reduction of pseudohypertelorism, the decompression of the optic nerve, and the meticulous reconstruction of the midface and skull base are performed in one session and are regarded as one entity. The results of the surgical management of 395 craniofacial injuries and the low rate of complications emphasize the advantages of the methods described in this article.
One hundred three patients underwent a modified sagittal ramus split osteotomy of the mandible. Maintenance of the temporomandibular joint relationship prior to the procedure was achieved postoperatively by using a three-dimensionally adaptable fixation bar. Techniques were also developed to avoid damage to the inferior alveolar nerve during the osteotomy and application of lag screws. These procedures avoided the disadvantages of lag screw osteosynthesis, and reduced relapse.
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 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.