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Biomedical subjects

K Lädrach

Publications and source records attributed to K Lädrach.

At least 19 recordsLinked to original sources
PubMed2000

Endovascular treatment of acute and subacute hemorrhage in the head and neck.

OBJECTIVE: Acute and subacute hemorrhage in the head and neck often represent a life-threatening situation. The goal of this study is to evaluate the indications for and contributions of endovascular techniques in the diagnosis and management of such severe cases. DESIGN: Seventy-two patients with acute or subacute intractable hemorrhage of the head and neck were treated over a period of 5 years: 2 patients had experienced trauma; in 6 cases the cause of bleeding was iatrogenic; and in 2 patients intraosseous arteriovenous malformations were manifested. Fifteen patients had tumors, 9 of whom had prior radiotherapy. Forty-seven patients presented with epistaxis (41 idiopathic and 6 during anticoagulation therapy). The endovascular therapy was performed using polyvinyl alcohol particles, fibered platinum or electrolytically detachable coils (Guglielmi detachable coils; Target Therapeutics, Fremont, Calif), a stent, glue (Ethibloc; Ethicon GmbH, Norderstedt, Germany, and Histoacryl; B. Braun Melsungen AG, Melsungen, Germany), or with a combination of these different embolic materials. RESULTS: The acute bleeding was successfully controlled in all cases. Fourteen patients (7 with epistaxis, 5 with tumors, and 2 with arteriovenous malformations) had to be embolized more than once before the bleeding could be controlled. The idiopathic, traumatic, iatrogenic, and remaining tumoral cases were treated only once. The long-term morbidity was 1.9%. CONCLUSIONS: Owing to the recent continuous advances in interventional radiologic techniques, it is possible to treat both acute and subacute life-threatening head and neck hemorrhage most efficiently. In many cases the endovascular therapy complements surgery.

Acute Disease↗
PubMed2000

Frameless computer-aided surgery system for revision endoscopic sinus surgery.

To increase the intraoperative safety factor and to acquire anatomic assistance during revision endoscopic sinus surgery (RESS), we used an optical computer-aided surgery (CAS) system that we developed collaboratively in Bern, Switzerland. During 1 year, 25 RESSs were performed with CAS: recurrent polyposis (n = 20), recurrent frontal recess stenosis (n = 3), and recurrent frontal recess stenosis with mucocele (n = 2). These patients were compared with a control group of 10 patients undergoing RESS without CAS. The same surgeon (M.C.) performed all operations, and there were no minor or major complications in either group. The clinical inaccuracy of our system is between 0.5 and 2 mm with paired-point and surface matching. The navigation system is an important aid to surgeons in identifying anatomic landmarks that are typically difficult to visualize in this type of surgery, thus reducing the stress placed on the surgeon.

Endoscopy↗
PubMed1999

The "Bernese" frameless optical computer aided surgery system.

OBJECTIVE: We report on two years of clinical experience with a frameless Computer Aided Surgery system developed in Bern, Switzerland. MATERIAL AND METHODS: Our navigation system is based on a preoperative computer-tomography (CT) scan (without markers) and an intraoperative optical tracking of head movements and of the surgical instruments. Using landmark and surface-based registration, the skull can be accurately correlated to the CT images. The three-dimensional positions of the surgical instruments, as well as the endoscopic images, are displayed in real time on a monitor. RESULTS: In the last two years, 109 computer-aided interventions have been successfully performed: 89 on the anterior skull base/paranasal sinuses, 15 on the lateral skull base, and 5 minimally invasive procedures on other locations in the skull. No complications occurred. The practical accuracy on the cadaver skull is between 0.5 mm and 1.2 mm, and the clinical accuracy is between 0. 5 mm and 2 mm. CONCLUSIONS: Our navigation system has proven its accuracy and usability. Surgeons feel very comfortable with the increased safety provided by the unequivocal identification of important anatomical structures.

Cadaver↗
PubMed1998

Open reduction without fixation of dislocated condylar process fractures: long-term clinical and radiologic analysis.

PURPOSE: This study evaluates the long-term results of open reduction without fixation for displaced fractures of the condylar process. PATIENTS AND METHODS: Clinical and radiologic examinations were performed on 27 patients with 29 operated joints an average of 6.7 years postoperatively. The postoperative result was evaluated on the basis of occlusal and joint function, as well as radiographic assessment of condylar changes. RESULTS: Clinically, satisfactory results were achieved. Radiologically, despite correct intraoperative alignment of the fractured segments, a slight medial deviation of the condylar process was found on the posteroanterior radiograph. However, in only two cases was a 20-degree deviation observed. On final follow-up, 48% of the cases had a normal condylar configuration radiologically, and in the remaining cases, normal function was established even though there were condylar changes. Fully exposed and devascularized condylar processes generally showed more severe changes than those in which partial vascularization was maintained. CONCLUSION: The surgical management described enables a satisfactory outcome to be achieved with dislocated condylar process fractures.

Adolescent↗
PubMed1998

[Computer-assisted surgical navigation with a dynamic mobile framework for the nasal fossae, sinuses and base of the skull].

Surgery of the skull base and of the paranasal sinuses is often difficult because of the complex anatomy and the delicate structures; serious complications (loss of vision, cerebral lesion) have been reported. To improve the safety of such operations, computer-assisted navigation surgery is increasingly being put to use. We introduce the system which was developed in Berne. Our computer-assisted system is based on an intraoperative pursuit of the head and instruments which are equipped with infrared diodes and registered by an opto-electronic system-camera. The CT-acquisition of the head is accomplished framelessly without a head-holding device. This allows free movement of the head during surgery. Between March and November 1997, 35 navigation operations were performed for various pathologies at the anterior and lateral skull base. The majority of the cases were endonasal operations. No surgical complications occurred inspite of the complexity of the operations. The measured accuracy of the system between the CT and the actual instrument location in the patient was 0.5-2 mm (mean : < 1 mm) for the anterior skull base and 1-2.5 mm (mean < 1.5 mm) for the lateral skull base. The intraoperative navigation system allows identification of essential anatomical structures and permits safe and efficient surgery without additional loss of time. In addition, such a system allows minimal invasive approaches, and new operations may become possible.

Adult↗
PubMed1995

Extended anterior subcranial approach for skull base tumors: long-term results.

The extended anterior subcranial approach differs significantly from more traditional surgical approaches to the skull base in that it allows a broad inferior access to the anterior skull base planes with tumor exposure from below rather than via the transfrontal route. The authors initially used the subcranial approach in 1978 for the treatment of high-velocity skull base trauma and certain craniofacial anomalies. In 1980 they expanded the indications to include the combined neurosurgical-otolaryngological resection of various skull base tumors. Osteotomy of the frontonasoorbital external skeletal frame provides optimum anterior access to the orbital and sphenoethmoidal planes as well as to the nasal and paranasal cavities while avoiding frontal lobe retraction and the external facial incisions characteristic of transcranial and transfacial approaches. The improved visualization of the anterior skull base and clival-sphenoidal region facilitates en bloc tumor removal, optic nerve decompression, exposure of the medial aspect of the cavernous sinus, and watertight realignment of the anterior cranial base dura. In this report the authors present their experience over the past 13 years with 104 patients who underwent operation via the extended subcranial approach. Because extensive frontal lobe manipulation and external facial incisions are avoided with this approach, intensive care unit and overall hospital stay are reduced, related complications are minimized, and postoperative cosmetic appearance is enhanced. The extended anterior subcranial method is therefore an excellent alternative to traditional transfacial-transcranial skull base approaches for the removal of selected skull base tumors.

Adolescent↗
PubMed1991

Treatment of 813 zygoma-lateral orbital complex fractures. New aspects.

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.

Bone Plates↗
PubMed1990

[The correction of craniofacial deformities].

Subject of this paper is to emphasize the advantages of our surgical procedure for the correction of craniofacial anomalies. Particularly for the fronto-orbital advancement in the hypertelorism and exophthalmus cases, this method enabled the reduction of the complication rate and the preservation of vital structures as well as a significant reduction of the morbidity rate. The advantages rendered by the bimaxillary osteotomy are discussed. The results and complications are evaluated.

Facial Bones↗
PubMed1989

Temporomandibular joint ankylosis: surgical treatment and long-term results.

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.

Adolescent↗
PubMed1989

Open reduction of the dislocated, fractured condylar process: indications and surgical procedures.

The subject of this paper is the evaluation of the results after surgical management of 29 dislocated fractures of the condylar process. Only fractures with total dislocation of the condyle out of the articulate fossa were surgically treated. The surgical procedure, making a broad exposure necessary, is detailed. The low rate of complications as well as the satisfactory function of the joints in spite of severe dislocation seems to confirm the surgical treatment of this type of fractures.

Adolescent↗
PubMed1988

New techniques for reproduction of the condyle relation and reduction of complications after sagittal ramus split osteotomy of the mandible.

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.

Bone Screws↗
PubMed1988

[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.

Adult↗
PubMed1987

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.

Bone Plates↗