[Recommendations for assessment of disability in private accident insurance-Interdisciplinary consensus-Status September 2024 : Recommended for use by the Specialist Society of Interdisciplinary Medical Expert Opinion (FGIMB) on 6 October 2023]. / Bemessungsempfehlungen zur Invalidität in der privaten Unfallversicherung ­ fachübergreifender Konsens ­ Stand 09/2024 : Von der Fachgesellschaft Interdisziplinäre Medizinische Begutachtung (FGIMB) e. V. zur Anwendung empfohlen am 06.10.2023.

The centerpiece in private accident insurance is the compensation in cases of disability, which must be determined by a physician within a certain time limit. The insurer contract specifies the compensation rate for loss or inability to function. In cases of insurance the medical expert has to refer to generally accepted revised or updated assessment recommendations in order to be able to apply the given framework to the specific individual disability situation of the insured person. This article deals with the interdisciplinary consensus benchmarks for the assessment of disability, which form the principles of a uniform medical assessment of accident-related functional disorders in the private accident insurance.With the publication of these new assessment recommendations developed under the guidance of the Specialist Society of Interdisciplinary Medical Expert Opinion (FGIMB), the recommendations published by Schröter and Ludolph in 2009 [12] are withdrawn, so that these are now replaced as the authoritative version by the assessment recommendations of the FGIMB.

[Extensor tendon injuries at the level of the proximal interphalangeal joint]. / Strecksehnenverletzungen in Höhe des Mittelgelenks.

Closed and open injuries of the extensor mechanism at the proximal interphalangeal (PIP) joint can involve the central slip, the lateral slips or both. They are classified as zone III injuries. All open injuries on the dorsal side of the PIP joint should raise suspicion of an extensor tendon injury that is frequently overlooked. The operative strategy consists of wound revision with extensor tendon suture or refixation of the central slip. Acute closed central slip injuries are clinically diagnosed (Elson test) after ruling out bony injuries to the joint. Nondisplaced avulsions of the central slip insertion or lacerations can be treated nonoperatively by splinting. For displaced avulsions and complex injuries the treatment is surgical. In overlooked injuries a typical deformity (buttonhole/Boutonnière deformity) develops within 1-2 weeks that is characterized by an extension lag of the PIP joint and hyperextension at the distal interphalangeal joint. In early cases, when passive extension is still complete (mobile buttonhole deformity) the central slip can be immediately reconstructed. In fixed deformities complete passive extension of the PIP joint has to be restored before surgery by hand therapeutic measures or PIP joint release. Depending on the pattern of the injury and the resulting defects, a number of reconstructive techniques have been established that are summarized in this article. The functional results can be limited by tendon adhesions, imbalance within the reconstructed extensor apparatus and stiff joints that can all restrict the range of motion. Therefore, active rehabilitation protocols are mandatory for optimal results.

[Joint arthrodesis in functionally favorable position : Considerations on measurement of disability in private accident insurance]. / Gelenkversteifung in gebrauchsgünstiger Stellung : Überlegungen zur Invaliditätsbemessung in der privaten Unfallversicherung.

If an accident results in a functional disorder that persists and permanently restricts physical and/or mental capacity, this is referred to as a disability. In private accident insurance it is the task of the medical expert to assess this disability by examining the medical findings and produce an assessment taking account of the literature and comparing against generally acknowledged guidance values. The priority dismemberment disability rating schedule initially provides loss values. For the "next lowest" disability levels for arthrodesis of extremity joints, the assessment recommendations are based on a functionally favorable position although this functionally favorable position is not more precisely defined.In this article the authors have defined these functionally favorable positions based on the information available in the literature. In particular, the operatively favorable settings for arthrodesis of the affected joint that are stated in the literature on trauma and orthopedic surgery were consulted. Of course, the functional perspective has been especially emphasized.A difficulty in achieving this was that the literature on arthrodesis is now almost only of historical value due to modern endoprosthetics. The knowledge gained was checked against medical experience and is expounded here.

[Reconstruction of the middle phalangeal base of the finger using an osteocartilaginous autograft from the hamate]. / Rekonstruktion der Mittelgliedbasis am Finger durch ein osteochondrales Transplantat vom Os hamatum.

OBJECTIVE: Restoration of proximal interphalangeal joint stability with preservation of mobility by reconstruction of the middle phalanx base using an osteochondral graft from the carpometacarpal joint surface of the hamate. INDICATIONS: Acute and older isolated destruction of the palmar middle phalanx base >25%. CONTRAINDICATIONS: Destruction of the head of the proximal phalanx, advanced chondropathia of the head of the proximal phalanx, extensive soft tissue injury with loss of skin coverage at the proximal interphalangeal joint. SURGICAL TECHNIQUE: The fractured middle phalangeal base is debrided and the defect is replaced by a size-matched autograft from the dorsal carpometacarpal hamate osteoarticular surface that is secured in place with miniscrews. POSTOPERATIVE MANAGEMENT: Immobilization for 2 weeks in a below-elbow cast in intrinsic plus position. Subsequent immobilization by a splint including the distal and proximal interphalangeal joint. RESULTS: Healing was achieved in 100% with restoration of joint congruity in 12 of 13 cases and slight subluxation in 1 case. Follow up was possible in 9 cases after 22 ± 16 (5-51) months. The average range of motion in the reconstructed joint achieved 0/9/73°, grip strength 82% of the unaffected side. Of the 9 patients, 5 developed a mild flexion contracture of the proximal interphalangeal joint. The DASH score achieved 4 ± 3 (0-8) points, pain at rest was 1 ± 2 (0-5), pain at exercise 2 ± 2 (0-5) on a visual analogue scale (0-10). All patients were satisfied and willing to undergo the procedure again. According to the literature, reconstruction of the base of the middle phalanx by using an osteochondral graft from the hamate is a reliable procedure to restore stability and mobility of the joint.

[Arthrodesis of the trapeziometacarpal joint]. / Die Arthrodese des Daumensattelgelenks.

OBJECTIVE: Bony fusion of the trapeziometacarpal joint. INDICATIONS: High demands concerning stability and strength of the thumb in primary or secondary osteoarthritis (e.g., posttraumatic osteoarthritis following injuries to the carpometacarpal joint of the thumb); instability in the absence of osteoarthritis due to malformations, ligamentous laxicity, and joint hypermobility; malformations; improvement of hand function in neurological disorders; salvage procedure after carpometacarpal arthroplasty provided bone stock is sufficient. CONTRAINDICATIONS: Osteoarthritis or stiffness of adjacent joints, activities demanding maximal mobility of the thumb, insufficient bone stock. SURGICAL TECHNIQUE: Resection of the articular surfaces of the trapeziometacarpal joint via a dorsal approach. After temporary K­wire transfixation, application of a dorsal T­shaped plate (fixed angled or not), replacement of the K­wire with a lag screw. POSTOPERATIVE MANAGEMENT: Immobilization for 8 weeks (radial below-elbow cast including the thumb metacarpophalangeal joint); standard radiographs on second postoperative day and after 8 weeks; removal of stitches after 2 weeks; with bony healing after removal of the cast, guided exercises to increase strength and mobility; full loading for manual tasks after 3 months. RESULTS: With regards to strength, stability, and pain reduction, results are rated as good and excellent with a high degree of patient satisfaction. Disadvantages are implant-related complications and nonhealing of the fusion in an average of 13% of patients. Nevertheless, the procedure is still indicated in young manual workers who tolerate some limitations of mobility.

[Conservative treatment of hallux valgus : What can be achieved with splints and insoles?] / Konservative Therapie des Hallux-valgus-Syndroms : Was kann man mit Schienen und Einlagen erreichen?

In hallux valgus syndrome conservative measures can only be applied to relieve the symptoms. Insoles, orthoses, and toe alignment splints cannot improve forefoot deformity. However, symptoms due to increased local pressure can be alleviated with orthotic devices. After surgically realigning the hallux, splints are helpful to retain joint congruency and assure proper toe position during soft tissue healing.

[Suture techniques and material in surgery of flexor tendons]. / Nahttechniken und Nahtmaterial in der Beugesehnenchirurgie.

Adhesions and scar formation between flexor tendons and the surrounding tissue are only contemporarily avoidable by movement of flexor tendons. Concepts with active follow-up protocols are more favorable than passive mobilization. The main risks of flexor tendon repair are rupture of the tendon suture, insidious gap formation and resistance to tendon gliding within the tendon sheath. Currently, there is no consensus with respect to the optimal suture technique or suture material. Nevertheless, there are some principles worth paying attention to, such as using stronger suture material, blocking stitches, suture techniques with four or more strands as well as circular running sutures. A technically acceptable compromise, even for the less experienced, is currently the four-strand suture combined with a circular running suture. It maintains sufficient stability for active motion follow-up protocols without resistance.

Effects of different components of the extracellular matrix on endothelialization.

The endothelialization of cardiovascular prostheses is known to improve their haemocompatibility. As such body-foreign materials often do not endothelialize spontaneously. A lot of in vitro studies are ongoing how endothelialization of biomaterials can be improved. In this study the influence of different components of a tissue-typical extracellular matrix (ECM) like laminin, fibronectin or gelatin on the formation of an endothelial cell monolayer and on the shear resistance of adherent cells on these substrates was studied.The study revealed that the density of human venous endothelial cells (HUVEC) monolayers differed markedly between cells grown on a natural ECM and cells grown on singularized components of an ECM (p < 0.001). Only HUVEC grown on laminin showed similar densities and a stress fiber pattern comparable to HUVEC grown on the ECM. HUVEC grown on gelatin- or fibronectin-coated coverslips were less firmly attached to the substrate; frequently individual HUVEC and even groups of cells detached.Concluding it seems that coating of implants with laminin supports the formation of shear resistant endothelial cell (EC) monolayer - superior to other ECM components.

[Arthroscopically assisted transcapsular refixation of the triangular fibrocartilage complex of the wrist]. / Die arthroskopisch unterstützte transkapsuläre Refixation des Discus triangularis am Handgelenk.

OBJECTIVE: Refixation of the triangular fibrocartilage complex (TFCC) to the ulnar capsule of the wrist. INDICATIONS: Distal TFCC tears without instability, proximal TFCC intact. Loose ulnar TFCC attachment without tear or instability. CONTRAINDICATIONS: Peripheral TFCC tears with instability of the distal radioulnar joint (DRUJ). Complex or proximal tears of the TFCC. Isolated, central degenerative tears without healing potential. SURGICAL TECHNIQUE: Arthroscopically guided, minimally invasive suture of the TFCC to the base of the sixth extensor compartment. POSTOPERATIVE MANAGEMENT: Above elbow plaster splint, 70° flexion of the elbow joint, 45° supination for 6 weeks. Skin suture removal after 2 weeks. No physiotherapy to extend pronation and supination during the first 3 months. RESULTS: In an ongoing long-term study, 7 of 31 patients who underwent transcapsular refixation of the TFCC between 1 January 2003 and 31 December 2010 were evaluated after an average follow-up interval of 116 ± 34 months (range 68-152 months). All patients demonstrated an almost nearly unrestricted range of wrist motion and grip strength compared to the unaffected side. All distal radioulnar joints were stable. On the visual analogue scale (VAS 0-10), pain at rest was 1 ± 1 (range 0-2) and pain during exercise 2 ± 2 (range 0-5); the DASH score averaged 10 ± 14 points (range 0-39 points). All patients were satisfied. The modified Mayo wrist score showed four excellent, two good, and one fair result. These results correspond to the results of other series. CONCLUSION: Transcapsular refixation is a reliable, technically simple procedure in cases with ulnar-sided TFCC tears without instability leading to good results.

[Subtalar arthrodesis]. / Die Arthrodese des Subtalargelenks.

OBJECTIVE: Realignment and stabilization of the hindfoot by subtalar joint arthrodesis. INDICATIONS: Idiopathic/posttraumatic arthritis, inflammatory arthritis of the subtalar joint with/without hindfoot malalignment. Optional flatfoot/cavovarus foot reconstruction. CONTRAINDICATIONS: Inflammation, vascular disturbances, nicotine abuse. SURGICAL TECHNIQUE: Approach dependent on assessment. Lateral approach: Supine position. Incision above the sinus tarsi. Exposure of subtalar joint. Removal of cartilage and breakage of the subchondral sclerosis. In valgus malalignment, interposition of corticocancellous bone segment; in varus malalignment resection of bone segment from the calcaneus. Reposition and temporarily stabilization with Kirschner wires. Imaging of hindfoot alignment. Stabilization with cannulated screws. Posterolateral approach: Prone position. Incision parallel to the lateral Achilles tendon border. Removal of cartilage and breakage of subchondral sclerosis. Medial approach: Supine position. Incision just above and parallel to the posterior tibial tendon. Removal of cartilage and breakage of subchondral sclerosis. Stabilization with screws. POSTOPERATIVE MANAGEMENT: Lower leg walker with partial weightbearing. Active exercises of the ankle. After a 6­week X­ray, increase of weightbearing. Full weightbearing not before 8 weeks; with interpositioning bone grafts not before 10-12 weeks. Stable walking shoes. Active mobilization of the ankle. RESULTS: Of 43 isolated subtalar arthrodesis procedures, 5 wound healing disorders and no infections developed. Significantly improved AOFAS hindfood score. Well-aligned heel observed in 34 patients; 5 varus and 2 valgus malalignments. Sensory disturbances in 8 patients; minor ankle flexion limitations. Full bone healing in 36 subtalar joints, pseudarthrosis in 4 patients.

[The volar locking plate for extension fractures of the distal radius]. / Die palmare winkelstabile Plattenosteosynthese bei Extensionsfrakturen des distalen Radius.

OBJECTIVE: Bony healing of dislocated distal radius fractures after open reduction and internal stabilization by locking screws/pins using palmar approach. INDICATIONS: Extraarticular distal radius fractures type A2/A3, simple extra- and intraarticular fractures type C1 according to the AO classification, provided a palmar approach is possible. CONTRAINDICATIONS: Forearm soft tissue lesions/infections. As a single procedure if a volar approach not possible. SURGICAL TECHNIQUE: Palmar approach to the distal radius and fracture. Open reduction. Palmar fixation of the plate to radial shaft with single screw. After fluoroscopy, distal fragments fixed using locking screws. POSTOPERATIVE MANAGEMENT: Below-the-elbow cast for 2 weeks. Early exercise of thumb and fingers, wrist mobilization after cast removal. Complete healing after 6-8 weeks. RESULTS: Ten patients averaged 100% range of motion of the unaffected side after 43±21 months. No complications observed. DASH score averaged 12±16 points; Krimmer wrist score was excellent in 7, good in 2, and fair in one.

Morphology of primary human venous endothelial cell cultures before and after culture medium exchange.

BACKGROUND: The evaluation of the interaction of human, venous endothelial cells (HUVEC) with body foreign materials on the cellular level cannot be performed in vivo, but is investigated in vitro under standard culture conditions. To maintain the vitality, proliferation and morphology of HUVEC seeded on body foreign substrates over days, the cell culture medium is usually exchanged every second day. It is well known, that alterations in the microenvironment of cells bear the risk of influencing cell morphology and function. In the current study the influence of cell culture medium exchange on HUVEC cytoskeletal microfilament structure and function was investigated. MATERIAL AND METHODS: HUVEC in the third passage were seeded on extracellular matrix (ECM) - which was secreted from bovine corneal endothelial cells on glass- until functional confluence was reached. The experiment started 11 days after HUVEC seeding with an exchange of the cell culture medium followed by a staining of the actin microfilaments with phalloidin-rhodamin 1.5 and 5 minutes after medium exchange. The microfilaments were documented by use of an Olympus microscope (IMT-2) equipped with a UV lamp and online connected to a TV chain (Sony XC 50 ST/monochrome) implying an OPTIMAS - Image analysis system. Prostacyclin was analysed in the cell culture supernatant. RESULTS: 1.5 min after culture medium exchange in the functionally confluent cultures a slight disturbance of the actin microfilament structure with a broadening of the marginal filament band, a partial disconnection of cell-cell contacts and the appearance of intercellular fenestrations were observed. 5 minutes after medium exchange a redevelopment of the slightly disturbed microfilament structure with a condensation and narrowing of the marginal filament band was seen. 12 h later a further consolidation of the microfilament structure occurred. In addition, a perturbation of the cultured HUVEC occurred after cell culture medium exchange. The prostacyclin concentration in the supernatant increased significantly after 1.5 min to 466 ± 543 pg·mL-1 (p <  0.001) and after 5 min to 408 ± 458 pg·mL-1 (p <  0.001), while in control cells the prostacyclin concentration did not change remaining in the range of 50 ± 48.9 pg·mL-1. CONCLUSION: This study revealed that the exchange of the cell culture medium led to a rapid disturbance of the HUVEC with stress fiber formation, disconnection of cell-cell contacts and an altered prostacyclin secretion, which had regressed nearly completely after 12 hours. Therefore, the evaluation of HUVEC on body foreign materials should be performed not earlier than 12 hours after cell culture medium exchange to avoid a misinterpretation of the endothelial cell morphological state. This procedure minimizes the risk of a misinterpretation of the endothelial cell morphology - caused by the culture medium exchange and not by the interaction between biomaterials and HUVEC.

[Ligament reconstruction for lunotriquetral instability using a distally based strip of the extensor carpi ulnaris tendon]. / Die Bandersatzplastik bei lunotriquetraler Instabilität mit einem distal gestielten Streifen der Extensor-carpi-ulnaris-Sehne.

OBJECTIVE: Stabilization of the lunotriquetral junction. INDICATIONS: Dynamic and static chronic instability without fixed dislocation of the carpals. CONTRAINDICATIONS: Chronically fixed dislocation of the carpals, ulnar impaction syndrome, osteoarthritis of the joint between hamate and triquetrum and other parts of the wrist joint, rheumatoid arthritis, chondrocalcinosis. SURGICAL TECHNIQUE: Restoration of the palmar portion of the lunotriquetral ligament using a distally based strip of the extensor carpi ulnaris tendon with temporary fixation of the lunotriquetral junction with K-wires. POSTOPERATIVE MANAGEMENT: Immobilization for 8 weeks with a radial cast that includes the first metacarpophalangeal joint. Removal of the K-wires after 8 weeks and exercise. RESULTS: The procedure with rare complications reliably restores stability of the lunotriquetral junction. Reduction of grip strength, pain during exercise, and a reduced range of motion persist. Overall, the results are predominantly good and excellent.

[Tenolysis of the flexor tendons in the hand]. / Tenolyse der Beugesehnen an der Hand.

BACKGROUND: Properly gliding flexor tendons is mandatory for the normal functioning of the finger and thumb. Any damage to tendons, tendon sheath or adjacent tissue can lead to the formation of adhesions that inhibit the normal gliding function. If adhesions limit the digital function and adequate hand therapy does not provide further progress, then surgical intervention should be considered. AIM: The authors' strategy and treatment algorithm for flexor tenolysis are presented in the context of the current literature. METHODS: There is no absolute indication for flexor tenolysis. The decision should be made in a motivated patient who has access to adequate postoperative hand therapy. It should be based on healed fractures and osteotomies, mature soft tissue coverage, intact tendons and gliding tissues, and a full range of passive flexion, and preferably extension of the affected joints. The principle of flexor tenolysis is the consequent resection of all adhesive tissue around the tendon inside and outside the tendon sheath, with preservation of as many pulley sections as possible. Therefore, extensive approaches are frequently necessary. Arthrolysis and the resolution of unfavorable scars, the resection of scarred lumbricals, and pulley reconstruction are additional procedures that are frequently performed. RESULTS: In the literature, improvement in the range of motion is between 59 and 84 %. Good and excellent functional results are reported in 60-80 % of the cases. Nevertheless, in selected cases, functional deterioration occurs. Flexor tendon ruptures after tenolysis were observed in 0-8 % of the patients. DISCUSSION: With regard to complications such as secondary tendon ruptures, loss of pulleys, and scar formation, flexor tenolysis is part of a reconstructive ladder that includes further procedures. In the case of failure or complications, salvage procedures such as arthrodesis, amputation, and ray resection or staged flexor tendon reconstruction including tendon grafting are recommended. After successful flexor tenolysis long-term hand therapy for at least 3-6 months is mandatory to maintain the intraoperative gain of function.

Influence of the coating with extracellular matrix and the number of cell passages on the endothelialization of a polystyrene surface.

The proper morphology and function of the vascular endothelium are prerequisites for a sufficient supply of the tissues. Endothelial cell (EC) dysfunction can lead to circulatory disorders and the development of cardiovascular diseases. The endothelialization of cardiovascular implants is a sophisticated task since EC miss their natural environment and physiological stimuli in vitro. In addition, different studies revealed that the EC behavior and morphology depended on the substrate and the passage number of the EC. Therefore, the comparison of endothelialization studies is very difficult, when passage and substrate are unknown.The aim of this study was to investigate the growth potential and cell morphology of human venous endothelial cells (HUVEC) as a function of different cell passages and different substrates (pristine polystyrene, tissue-typical ECM-coated polystyrene). The study revealed that HUVEC morphology and growth potential were significantly different on pristine polystyrene compared to the basal lamina-like ECM-coated polystyrene surface. Furthermore, it became obvious that the passage of the cells affected the endothelialization of the polystyrene surface significantly. In conclusion, this study emphasized the need for a critical consideration of EC data whereas a simple comparison of results is not possible if EC age and passage is unknown.

[Arthroscopy of the distal radioulnar joint]. / Die Arthroskopie des distalen Radioulnargelenks.

OBJECTIVE: Insertion of a small joint arthroscope into the proximal and distal parts of the distal radioulnar joint (DRUJ) allows visualization of the proximal pouch of the DRUJ, the joint surfaces of the sigmoid notch and the ulnar head, the convexity of the ulnar head and the proximal ulnar-sided surface of the triangular fibrocartilage complex (TFCC). INDICATIONS: Evaluation of joint pathologies in ulnar-sided wrist pain, especially in cases without diagnostic findings in standard X-rays and MRI, suspected cartilage lesions without osteochondral changes (signs of osteoarthritis), undefined swelling of the DRUJ in suspected synovitis, removal of loose bodies and arthroscopical synovialectomy, suspected lesions of the deep part of the TFCC, respectively foveal avulsions, wear or superficial tears of the proximal TFCC and arthroscopic-assisted ulnar shortening. CONTRAINDICATIONS: Significant changes of the local topographical anatomy, extensive scar formation, ulna plus variance, local infection or open wounds, affected sensibility in the area of the dorsal branch of the ulnar nerve, fractures of the sigmoid notch or the ulnar head, capsular tears causing effusion of irrigation fluid. SURGICAL TECHNIQUE: In vertical extension of the wrist, two portals are created on the dorsal side of the DRUJ between the extensor digiti minimi and extensor carpi ulnaris tendons. Partial visualization of the ulnar head, the sigmoid notch, the proximal pouch of the DRUJ, and the proximal surface of the TFCC. POSTOPERATIVE MANAGEMENT: Following isolated diagnostic arthroscopies immobilization of the wrist in a semicircular ulnar-sided cast for 1 week. No extensive load to the wrist for 4 weeks. RESULTS: Still rarely performed procedure for diagnosis and therapy of ulnar-sided wrist pain. Technically demanding with a flat learning curve and anatomy-related obstacles. A complete view of the joint is not always accessible. Rare complications are injuries of the extensor digiti minimi tendon as well as contusion or sectioning of the transverse branch of the dorsal branch of the ulnar nerve. In distinct cases this procedure offers valuable additional information about the distal radioulnar joint.

[Rheumatic forefoot deformities]. / Rheumatische Vorfußdeformität.

The frequency and extent of rheumatic forefoot deformities have been greatly reduced since the introduction of disease-modifying antirheumatic drugs (DMARD). The accompanying reduction in arthritic destruction of joints opens up new treatment options whereby priority is given to joint preservation. This is true for the first middle foot ray as well as for the small toe rays. Whereas resection arthroplasty of the metatarsophalangeal joints II-V was previously considered the gold standard treatment, joint-preserving operative procedures (e.g. metatarsal osteotomy and periarticular soft tissue interventions) are now being increasingly more propagated. Resection arthroplasty of the first midfoot ray has major biomechanical disadvantages so that it is not surprising that reconstructive procedures are given priority. In patients with severe arthritic destruction of the first metatarsophalangeal joint, arthrodesis has substantial biomechanical advantages compared to resection arthroplasty. Nevertheless, it has not yet been confirmed that fusion leads to superior clinical results.

Radiographic contrast media alterate the localization of actin/band4.9 in the membrane cytoskeleton of human erythrocytes.

Different radiographic contrast media (RCM) were shown to induce morphological changes of blood cells (e.g. erythrocytes or thrombocytes) and endothelial cells. The echinocytic shape change of erythrocytes, particularly, affords alterations of the membrane cytoskeleton. The cytoskeleton plays a crucial role for the shape and deformability of the red blood cell. Disruption of the interaction between components of the red blood cell membrane cytoskeleton may cause a loss of structural and functional integrity of the membrane. In this study band4.9 and actin as components of the cytoskeletal junctional complex were examined in human erythrocytes after suspension in autologous plasma or in plasma RCM mixtures (30% v/v Iodixanol-320 or Iopromide-370) followed by a successive double staining with TRITC-/FITC-coupled monoclonal antibodies. After adding Iopromide-370 to the plasma in practically none of the cells the rounded conformation of the membrane cytoskeleton - as it appeared in cells suspended in autologous plasma - was found. In addition, Iopromide-370 induced thin lines and coarse knob-like structures of band4.9 at the cell periphery while most cell centers were devoid of band4.9, and a box-like arrangement of bands of band4.9. A dissociation between colours red (actin) and green (band4.9) occurred as well. In contrast, erythrocytes suspended in a plasma/Iodixanol-320 mixture showed a membrane cytoskeleton comparable to cells suspended in autologous plasma, Similar results were found with respect to the distribution of actin. This study revealed for the first time RCM-dependent differences in band4.9 activities as possible pathophysiological mechanism for the chemotoxicity of radiographic contrast media.