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Biomedical subjects

C J Wirth

Publications and source records attributed to C J Wirth.

At least 55 records · Page 3Linked to original sources
PubMed2000

Bioartificial cartilage.

Cartilage is a highly differentiated tissue. Its three-dimensional composition of cells and matrix is able to resist intensive mechanical loads. The capacity of cartilage tissue for regeneration is limited. Chondrocytes are responsible for matrix production of cartilage tissue. Enzymatic isolation and expansion of chondrocytes with cell culture techniques has been improved in the last years. These cells can be cultured on different three-dimensional culture systems suitable for transplantation to repair localized cartilage defects. Two types of bioresorbable polymer fleece matrices (PLLA and a composite fleece of polydioxanone and polyglactin) and lyophilized dura as a biological carrier are tested. Phenotypic and morphological appearance of the cultured articular rabbit chondrocytes is preserved on all three types of transport media. Production of glycosaminoglycans has been shown by Alcian blue staining, production of collagen by azan staining. Chondroitin 4- and 6-sulfate are detected immunohistochemically in the created constructs. The different carriers have specific characteristics regarding their suitability for the creation of bioartificial cartilage. This tissue is transplantable into articular cartilage defects and could, therefore, improve the minor intrinsic healing capacity of cartilage tissue.

Animals↗
PubMed2000

[Tissue engineering for therapy of osteochondral cartilage lesions].

Cartilage defects still represent an unsolved problem in joint surgery. The intrinsic healing capacity of cartilage is insufficient and at best leads to reparative tissue like fibrous cartilage or cartilage like tissue regardless of the therapy applied. Cell culture techniques and generation of tissue specific matrix tread new paths to treat traumatic cartilage lesions. This technology referred to as tissue engineering allows for formation of constructs consisting of chondrocytes capable of production of cartilage specific matrix in combination with three-dimensional cell carriers. Polymers such as polylactid, co-polymers like polydioxanon with polyglactin and lyophilized dura have been used successfully to create such constructs with chondrocytes of different animal species. Cartilage specific compounds can be detected by histological and immunohistochemical techniques. To apply these constructs in humans, the distinguishing characteristics and problems of cell culture with human chondrocytes have to be considered. A further improvement of the artificially created tissue is conceivable using growth factors even including genetic manipulation of the applied cells.

Animals↗
PubMed1999

[Not Available].

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Journal Article↗
PubMed1999

[Not Available].

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Journal Article↗
PubMed1999

[Growth behavior of chondrocytes on various biomaterials].

Chondrocytes can be cultured on different three-dimensional culture systems suitable for transplantation to enhance the repair of localized cartilage defects. Articular cartilage chondrocytes from adult rabbit knees and from bovine calf metacarpophalangeal joints were isolated by enzymatic digestion and cultured in a monolayer system to amplify cell count. After amplification the cells were seeded on different biocompatible materials. We investigated two types of bioresorbable polymer fleece matrices (a composite fleece of polydioxanon and polyglactin and a resorbable poly-L-lactic acid fleece) and lyophilized dura as a biological carrier. On all three types of transport media the phenotypic and morphological appearance of cultured chondrocytes could be observed. The production of glycosaminoglycans was revealed by Alcian blue staining and immunohistochemical detection of Chondroitin-4 and 6-sulfate in the created constructs. The material properties of the carriers allow for transplantation of the artificial cartilage-like products into full thickness articular cartilage defects and could therefore improve the minor intrinsic healing capacity of cartilage tissue. Bioartificial cartilage may become a future perspective in the treatment options of orthopaedic and plastic surgery.

Animals↗
PubMed1999

Reconstructive operations for the paralyzed shoulder in brachial plexus palsy: concept of treatment.

Sixty-three patients with persistent brachial plexus palsy underwent a transfer of the trapezius muscle and 14 patients a shoulder arthrodesis. Thirteen female and 64 male patients were treated with a mean age of 31 yr (17-69 yr). The average follow-up period was 14 months (6-50 months). In all cases, the trapezius transfer resulted in increased abduction from 6.1 degrees to an average of 36.4 degrees (20-80 degrees) and forward flexion from 13.8 degrees to an average of 31.9 degrees (10-90 degrees). The multidirectional shoulder instability was improved in 60 patients. Strength and functional improvement was, on average, greater following shoulder arthrodesis (abduction from 9.6 to 59.3 degrees (40-90 degrees), forward flexion from 11.4 to 50.7 degrees (30-90 degrees)). In patients with brachial plexus palsy, trapezius transfer resulted in an improvement of shoulder function and stability as well as subjectively. The increase in function was, however, less pronounced in comparison with shoulder arthrodesis. The advantages of the transfer are the regaining of normal passive function and the shorter duration of surgery. Shoulder fusion is more suitable for those patients who require the best possible extent of function and strength in the shoulder.

Adolescent↗
PubMed1998

The dilemma with multiply reoperated knee instabilities.

The treatment of instability of the multiply reoperated knee is a complex problem. The causes for failure are numerous and include repeated trauma, insufficient fixation and non-anatomic placement of the graft, inadequate replacement material, isolated anterior cruciate ligament (ACL) reconstruction in complex knee instability or the use of a ligament prosthesis. With every surgical procedure, however, the anatomical and technical conditions become worse. Problems like degenerative changes, joint stiffness and gait abnormalities occur and often become a more focal point than the instability itself. The purpose of this paper is to present the problems and the dilemma of instability of the multiply reoperated knee and the possible solutions. Between 1976 and 1996, a total of 1752 ACL reconstructions were carried out in Munich and Hannover. Of these, 228 (13%) were revision, mostly of failed ACL reconstructions performed elsewhere. Since 1989, we have chosen the severest cases from this group (more than three operations on the same knee) for this study. Seventeen patients were investigated who had undergone up to 25 operations. The mean number of operations was 7. All primary operations were performed in other hospitals. In 10 cases only the ACL reconstruction was performed as a final procedure, mostly in combination with other procedures like medial meniscus replacement, extra-articular stabilization or arthrolysis. In the other cases operations such as osteotomies, arthrodesis or amputation were necessary. The results present the main dilemma in instability of the multiply reoperated knee since they were not successful in all patients. Finally, 15 patients report still having instability, pain or swelling in isolation or in combination. Nine patients were satisfied with their subjective results. Even after the socalled definitive procedures, certain complications arose. The main goal in the treatment of instability of the multiply reoperated knee is to avoid a series of operations, hospitalization and history of illness. General revision surgery for the entire complaint is not the aim of the treatment. The specific problem of the patient should be extracted from the complex situation, and this should be solved with the most limited procedure possible only.

Adult↗
PubMed1998

Synthesis of articular cartilage-like tissue in vitro.

Defects in mature articular cartilage do not heal without residues, and therefore they remain a challenging problem in orthopaedic surgery. Modern tissue culture techniques facilitate the synthesis of cartilage-like tissue. A requirement of retaining the phenotypic characteristics of chondrocytes in vitro is the use of three-dimensional culture techniques. Articular chondrocytes of adult rabbits were isolated and cultured on different transplantable media for several weeks. A resorbable fleece, a non-absorbable net and lyophilized dura were used. Viability was tested by immunohistochemical techniques. Deposition of extracellular matrix could be observed by electron microscopy. The phenotypical and morphological appearance of cultured chondrocytes was preserved on the resorbable polymer fleece and the lyophilized dura. Cells cultured on the non-absorbable net had a more fibroblastic appearance. The resorbable fleece is apparently most suitable in terms of viability of the cultured chondrocytes and biocompatibility. The cultured three-dimensional artificial cartilage constructs reveal a future possibility for autologous cartilage transplantation into mature cartilage defects.

Animals↗
PubMed1998

Follow-up results 17 years after resection arthroplasty of the great toe.

Resection arthroplasty of the first metatarsophalangeal joint is a well-known operation. The follow-up results more than 17 years after arthroplasty for hallux valgus are reported and discussed. Between 1971 and 1980, 335 resection arthroplasties were performed on 205 patients. The sole indication for resection arthroplasty of the great toe in this study was hallux valgus. The technique involved removal of the proximal one-third of the phalanx with interposition of a capsular flap, occasionally including temporary Kirschner wire fixation. After 17.6 years on average, 102 patients were re-examined clinically and radiographically. Questionnaire assessment revealed a significantly prolonged walking distance, and 70% of the patients were pain-free at follow-up investigation, whereas 67% suffered from severe pain before the operation. Clinical evaluation showed diminished weight-bearing of the great toe during walking and a reduced range of motion of the resected first metatarsophalangeal joint. Radiographic shortening of the proximal phalanx was 37%. The average hallux valgus angle was 23 degrees at follow-up and 34 degrees prior to surgery. The unacceptably high rate of hallux valgus relapse, especially due to a high intermetatarsal angle, emphasizes the unsatisfactory long-term results of the resection arthroplasty. We now recommend this operation for older patients only, and a differentiated approach using reconstructive procedures according to the clinical and radiographical situation for younger patients.

Adolescent↗
PubMed1998

Trapezius transfer after brachial plexus palsy. Indications, difficulties and complications.

Most brachial plexus palsies are due to trauma, often resulting from motorcycle accidents. When nerve repair and physiotherapy are unsuccessful, muscle transfer may be considered. Paralysis of the deltoid and supraspinatus muscles can be addressed by transfer of the trapezius. Between March 1994 and June 1997 we treated 38 patients with brachial plexus palsy by trapezius transfer and reviewed 31 of these (7 women, 24 men) after a mean follow-up of 23.8 months (12 to 39), reporting the clinical and radiological results and subjective assessment. The mean age of the patients was 29 years (18 to 46). The operations had been performed according to the method of Saha described in 1967, involving transfer of the acromion with the insertion of the trapezius to the proximal humerus, and immobilisation in an abduction support for six weeks. Rehabilitation started on the first postoperative day with active exercises for the elbow, hand and fingers, and electrical stimulation of the transferred trapezius. All 31 patients had improved function with a decrease in multidirectional instability of the shoulder. The average increase in active abduction was from 7.3 degrees (0 to 45) to 39 degrees (25 to 80) at the latest review. The mean forward flexion increased from 20 degrees (0 to 85) to 44 degrees (20 to 90). Twenty-nine of the 31 were satisfied with the improvement in stability and function. Trapezius transfer for brachial plexus palsy involving the shoulder improves function and stability with clear subjective benefits.

Adolescent↗
PubMed1997

[Trapezius transfer in deltoid paralysis].

In most cases the genesis of brachial plexus palsy is traumatic, often because of bike accidents. If physiotherapy and neurosurgical procedures such as nerve repair do not have the desired outcome, muscle transfer operations are possible. The results of our favored transfer of the trapezius muscle to compensate paralysis of the deltoid muscle will be presented. Preoperatively radiological, clinical and electromyographic examinations are necessary. Our results are based upon the clinical and radiological check ups and the subjective assessment of the patients. Thirty-one patients (7 female, 24 male) underwent a trapezius transfer between March 1994 and December 1996. The average age was 29 years (range 18-46 years). We performed the operations using a modification of Saha's technique. With the patient in lateral decubitus position and protection of the opposite plexus, a sagital skin incision is the first step, followed by the preparation of trapezius and deltoid muscle as well as the bony parts of the shoulder (acromion, clavicle, scapular spine). The deltoid origin is cut from the lateral third of the clavicle, the acromion and the lateral half of the scapular spine. The next step is transection of the roof of the acromion and the lateral clavicle. After elevation of the remaining trapezius insertions from the clavicle and scapular spine, the proximal humerus is exposured by splitting the partly detached deltoid muscle longitudinally. Then the acromion fragment and humerus are prepared for the bone-to-bone contact. In 90 degrees of abduction the acromion fragment with its trapezius insertion is transferred and fixed to the humerus with two 4.5-mm screws. Finally the deltoid is sutured on the top of the trapezius and the skin is closed over two suction drains. Postoperatively we immobilize the operated arm in an abduction support for 6 weeks. The physiotherapy program starts on the first postoperative day with active training of elbow, hand and fingers and electrostimulation of the transferred trapezius muscle. Six weeks after the procedure we take an X-ray and start with progressive adduction of the arm. The preoperative subluxation of the humeral head was abolished in all cases. We achieved an average increase of active abduction from 7.3 degrees (range 0-45 degrees) preoperatively to 39.2 degrees (range 25 degrees-80 degrees) 1 year after the operation; the increase of forward flexion was from 20 degrees (range 0 degrees-85 degrees) to 43 degrees (range 20 degrees-90 degrees). All patients were satisfied with the improvement of stability and function of the operated shoulder. Finally we can conclude that the trapezius transfer for flail shoulder gives a satisfactory outcome regarding shoulder function and stability as well as the subjective situation of the patients.

Adolescent↗
PubMed1997

[Effect of surgical technique on meniscus transplants. A histological, animal experiment study].

After transplantation, a meniscus undergoes alterations in mechanical loading, which causes changes in its histological structure. We studied the degenerative effects on meniscus and tibial cartilage resulting from variations in the congruity or the isometric fixation of medial meniscus transplants. In three groups of five sheep each, the menisci were transplanted in three different ways, using the same operative approach. The menisci were evaluated 24 weeks after operation. In group 1, the meniscus was totally detached from its base at the capsule and refixed without changes in the congruity or isometry. This group provided the basic data. In group 2, the contralateral medial meniscus was turned upside down and transplanted. The reattachment was performed according to isometric conditions. With this technique the congruity of the tibial and femoral surface was modified. In group 3, the medial meniscus was reimplanted by choosing defined non-isometric fixation points for the anterior and posterior meniscal ligaments without changing the position of the corpus. For evaluation, the morphological alterations of meniscus and tibial cartilage were assessed by the Jackson score. The more distinct changes of the meniscus were assessed histologically by three criteria: surface cells, surface fibers and changes in the meniscus center. The highest degree of degenerative changes occurred in group 3 (score 4.5); however, considerable changes were also found in group 2 (score 3.5). Incongruous or non-isometric placement of a meniscal graft will lead to degeneration and failure of the graft.

Animals↗