[Standardized computer-based documentation system for diagnoses and medical performance in orthopedics and traumatology. Development and initial application]. / Standardisiertes EDV-gestütztes Befundungs- und Leistungsdokumentationssystem für die Orthopädie bzw. Traumatologie. Entwicklung und erste Anwendung.

INTRODUCTION: Increasing demands on quality assurance und medical performance documentation require an immediate and evaluable documentation in the outpatients' department. Presentation of a new computer-based diagnostic system for reporting and medical performance documentation. METHODS: Development and initial application of the system in three big orthopedical or traumatological hospitals. Judgements about the feasibility of immediate documentation in outpatients' departments. RESULTS: Presentation of an outpatients' departments diagnostic system with textblock-oriented anamnesis or anatomy-related diagnosis through pre-structured examination checklists. Coding of ICD-9/-10 as well as AO-classification and AIS (abbreviated injury scale). Implementation of scorings. Medical performance documentation through forms including pre-defined billing codes. Presentation of the documentation flow and its transfer into other contexts. DISCUSSION: Pure text-based clinical results do not allow sufficient evaluation for quality assurance and medical performance documentation. However, a computer-based and immediate documentation in outpatients' departments should not mean a significantly increased workload for physicians.

Development of a standardised computer-based documentation system for diagnoses and medical performance in orthopeadics/traumatology.

INTRODUCTION: Increasing demands on quality assurance und medical performance documentation require an immedate and evaluable documentation in the outpatients' department. Presentation of a new computer-based diagnostic system for reporting and medical performance documentation. METHODS: Development and initial application of the system in three big orthopeadical or traumatological hospitals. Judegements about the feasibility of immediate documentation in outpatients' departments. RESULTS: Presentation of an outpatients' departments diagnostic system with textblock-oriented anamnesis or anatomy-related diagnosis through pre-structured examination checklists. Coding of ICD-9/-10 as well as AO-classification and AIS (abbreviated injury scale). Implementation of scorings. Medical performance documentation through forms including pre-defined billing codes. Presentation of the documentation flow and its transfer into other contexts. DISCUSSION: Pure text-based clinical results do not allow sufficient evalutation for quality assurance and medical performance documentation. However, a computer-based and immediate documentation in outpatients' departments should not mean a significantly increased workload for physicians.

Investigation of silicone oil and fumed silica in an adjuvant animal model.

Human adjuvant disease is the label given to a syndrome that resembles a connective tissue disease such as scleroderma and that has been hypothesized to follow augmentation mammoplasty with silicone gel implants or silicone with adulerants. To date, there is no proof that pure silicone is the cause of these symptoms. The cases presented in the literature suggest a comparison to the events seen in the rat adjuvant arthritis model. Male Lew/SsN rats (n = 65) were used. To evaluate both the adjuvant and antigenic properties of the gel implant, variations of the standard Freund's complete adjuvant inoculum were prepared. Tested were the abilities of low molecular weight silicone to act as an adjuvant and for fumed silica to act as an antigen by modifying a rat adjuvant arthritis model to include silicone and fumed silica. On day 0, 0.25 ml of each inoculum was injected intradermally into the plantar aspect of the hindfoot of each rat. The foot diameter was recorded at each time period, compared with the contralateral hindfoot, and normalized to controls at regular time periods over the course of 120 days. Silicone oil did not act as an adjuvant. Furthermore, fumed silica alone did not act as an antigen; however, it is capable of eliciting a reaction that is both delayed and uncharacteristic of the rat adjuvant arthritis model. These results indicate that "human adjuvant disease" may be inappropriate and misleading.

Pillared-surface microstructure and soft-tissue implants: effect of implant site and fixation.

Previous work with subcutaneous implants in a rat animal model has shown that pillarlike surface microstructure will reduce fibrosis and enhance blood vessel approximation to the implant surface when compared with nontextured controls. This study was designed to determine the effect of microtissue anatomy and implant site on the observed response, as well as the effect of implant fixation. The lateral posterior sites were found to contain a fat pad which produced a dramatically reduced fibrosis for the micro-structured implants compared with smooth controls. Although significant differences between pillar-micro-structured implants and controls were found for most sites, neither fascia nor muscle reduces the level of cellular response to the same degree as fat. Suture fixation of the implants did not produce a significantly different response in these tests. The occupation of the interpillar spaces by fat and moderation of interfacial shear forces is proposed as a mechanism to explain these results.

Histologic comparison of breast implant shells with smooth, foam, and pillar microstructuring in a rat model from 1 day to 6 months.

The purpose of this study was to determine the soft-tissue response to silicone breast implants with different surface morphologies and to correlate implant microtexturing with capsular formation. Using a rat model, we inserted breast implants having three types of shells: micropillared, silicone foam, and smooth silicone (control). We used 96 adult male Sprague-Dawley rats weighing between 250 and 300 gm. Thirty-two rats were assigned to each of the three shell groups. Within each shell group, 4 rats were implanted for 24 hours, 4 for 4 weeks, 4 for 8 weeks, 4 for 12 weeks, 4 for 16 weeks, 4 for 20 weeks, and 4 for 24 weeks. The rats were sacrificed at the end of each time interval, and periprosthetic tissue was obtained for histologic analysis. Our results show a stable soft-tissue response with some macrophages and fibroblasts for the smooth silicone shell group; capsule thicknesses were 10 to 12 cells with interwoven collagen. The silicone foam prolonged the active cellular response with regard to macrophages, fibroblasts, and multinucleated giant cells, along with random collagen deposition and alternating thin and thick capsular areas. The micropillar group had a more stable cellular response, with macrophages and fibroblasts, along with disruption of the long-range orientation of collagen fibers.

Placement of a feeding button ("one-step button") as the initial procedure.

The procedure of choice for enteral feeding access is now percutaneous endoscopic gastrostomy (PEG). Standard PEG tubes have the disadvantages of clogging, stomal enlargement, and external bulkiness. Button replacement tubes can covert the more cumbersome PEG tubes to low external profile devices. A procedure and an early experience is described for placement of a button as a single-step procedure. This procedure is an over-the-wire, "push" procedure. Sixty-nine buttons were placed, 47 (61%) for neurologic reasons and 22 (32%) for cancer and other reasons. In 49 of the 69 (71%), there was no difficulty at all with insertion, and in only two (3%) could the button not be placed. Complications were assessed at 48 h and at 3 wk. No complications were found in 61 (90%). In only two patients (3%) were there serious complications (gastro-colon-cutaneous fistula and "peritonitis"). The One-Step Button represents a rapid, safe procedure for the placement of a low-profile PEG with its attendant advantages.

Development of an implantable drug delivery catheter.

A microtextured, pillared drug delivery system has been designed and tested in rabbits. This model has allowed for the calculation of the mass transport rate indicating after a 4 week time period a pillar device's mass transport rate K1 [min-1] is K1p 1.54 x 10(-2) in contrast to the smooth control which is K1C .043 x 10(-2) and K1im IM which is 0.136 x 10(-2). As a result of these experiments, it is apparent a micropillared drug delivery system is an order magnitude faster than an intramuscular injection and is 30 times faster than the smooth control device. The etiology for this difference is related to close blood vessel proximity and minimal to no fibrous capsule formation with the micropillared implant. Finally, even after a 6-month implantation time, the pillared device has greater reproducibility regarding curve profile and there is no loss in magnitude or rate of mass transport, in contrast the smooth control devices in many instances resulted in complete occlusion with total loss of mass transport capabilities.

Microvascular A-V shunts and the growth of autologous tissue flaps in Millipore chambers.

An animal model was developed using the male Sprague-Dawley rat to establish a protocol and design criteria for the growth of autologous tissue based on a microvascular pedicle. It became apparent that growth within the chamber depended heavily on membrane porosity and the presence of the microarteriovenous shunt. Different membrane porosities ranging from 0.0, 0.25, 1.2, to 8.0 microns were evaluated (n = 48). Optimal growth occurred with the 1.2-microns and the 8.0-microns micropore Millipore. Growth within the chamber consisted of a radial deposition of collagen and neovascularization originating from the arteriovenous (A-V) anastomosis. In contrast, control chambers (no A-V anastomosis), with the preceding range in membrane porosity, experienced little to no cell growth. In addition, the majority of A-V shunts did not remain patent in chambers having 0.0-microns porosity or 0.25-microns porosity. Thus it is apparent that a strong relationship exists between membrane porosity, patency, and in situ vascularization allowing for the proliferation of cells and collagen.

Analysis of the soft-tissue response to components used in the manufacture of breast implants: rat animal model.

The implant-tissue response to the silicone gel mammary prosthesis requires a more thorough evaluation in light of recent concerns related to human connective-tissue diseases, contracture, infection, and neoplasia. The silicone prosthesis is not a homogeneous implant but is a milieu of various silicone chemistries. Silicone polymer precursors and prosthesis components (silicone shells, shells extracted of their low-molecular-weight components, silica-free silicone, silicone oil, fumed silica, and silicone extract) were implanted subcutaneously using a nonhemorrhagic technique into the backs of Lew/SsN rats (n = 90), two implants per rat, for periods of 7, 14, 28, 56, and 90 days for a total of 6 implants per material per time period. Histologic analysis was performed on specimens from the harvested soft tissue. The intensity of the cellular and capsular response was lowest for the silicone oil and increased as the material's molecular weight increased and material compliance decreased. Fumed silica elicited the most highly reactive cellular response. From this study it is apparent that the polymer's molecular weight influences its migration, encapsulation, and intensity of cellular response. Further, the silicone extract distillate elicited a highly intense cellular response with pronounced lymphocyte invasion. The human relevance of this work awaits further correlation with implant retrieval and in vivo performance.

The use of coralline hydroxyapatite in a "biocomposite" free flap.

An animal model was developed to determine the feasibility of vascularizing a porous biomaterial and transferring it as part of a free flap to a recipient site with enhanced resistance to infection due to the maintenance of a blood supply. To that end, the experiment was divided into three stages. Stage 1 compared the soft-tissue response of Interpore-200 to Interpore-500, both continuously porous hydroxyapatite materials implanted beneath the panniculus carnosus of the male Sprague-Dawley rat. Pore size was an important factor as it influenced vascular ingrowth, with Interpore-200 vascularizing earlier (complete at 1 week) and more intensely. Interpore-200 was therefore used for the remainder of the experiment. After 1 week of tissue ingrowth, the implants were moved from the abdomen to the skull on a vascular pedicle as a "biocomposite" free flap. Stage 2 was the histologic evaluation of 15 "biocomposite" free flaps over various time intervals up to 8 months. The free flaps formed a fibrous union to the skull, while a simple nonvascularized Interpore-200 onlay graft (stage 2 control) demonstrated a bony union in three of four implants placed up to 2 months. Stage 3 confirmed the free flap's resistance to bacterial infection. A highly significant difference (p less than 0.005) in infection rates was demonstrated between the "biocomposite" and nonvascularized stage 3 controls with no Pseudomonas growth from 9 of 10 cultures of the free flaps 5 days after exposure to 10(4) Pseudomonas aeruginosa, while stage 3 controls demonstrated Pseudomonas growth in all cultures (heavy growth in 8 of 10). The "biocomposite" free flap has excellent potential to provide form and structure to wounds requiring reconstruction where bacterial contamination is a significant risk factor.

In vitro and in vivo testing of an electrocatalytic glucose sensor.

A prerequisite for the development of an implantable artificial pancreas is the availability of a stable, long-life glucose sensor. Platinum (Pt) catalyzed electrodes have been demonstrated in vitro to show high sensitivity to glucose and long cycle life but are more sensitive to co-reactants compared with enzymatic methods. The authors developed a special data processing method (compensated net charge ratio, or CNCR) in which the measured electrode response is very sensitive to glucose, completely insensitive to urea, and only moderately sensitive to amino acids. Other endogenous and exogenous co-reactants show only minor interferences. The CNCR method involves the determination of the ratio of net oxidation charge to total charge during one complete cycle of a cyclic voltammogram. Prototype electrodes tested in vitro in spiked plasma have shown typical sensitivities of greater than 2 x 10(-4) CNCR units per 1 mg/dl change in glucose concentration, with linear response up to 400 mg/dl. For in vivo testing, a modified 5 F vascular catheter with membrane covered surface mounted electrodes was used at a vena cava site in swine. Several sensor designs were tested in vivo, with sensitivities of 1-5 x 10(-4) CNCR units (mg/dl).

Natural-Y Même polyurethane versus smooth silicone: analysis of the soft-tissue interaction from 3 days to 1 year in the rat animal model.

The polyurethane foam-covered breast prosthesis is experiencing increased clinical use. The polyurethane is felt to be responsible for altering capsule formation and reducing the contracture rate. This study characterizes the soft-tissue response to the Natural-Y Même polyurethane foam versus smooth silicone in a rat model. Implants were fashioned from an unbacked polyurethane foam specimen used to cover the Natural-Y prosthesis, a silicone shell covered with the Natural-Y foam, and a smooth silicone control. Materials were placed subcutaneously into the backs of male Lew/SsN rats (n = 81) for 3, 7, 14, and 28 days and 3, 6, and 12 months. Implants were then harvested with their soft-tissue response and evaluated histologically. Analysis demonstrates that microstructuring of a surface, as opposed to a smooth material, will dramatically alter the early, intermediate, and late wound-healing events. The soft-tissue response was observed to be dependent on implant site, material chemistry, and morphology as characterized by exudate formation, macrophage invasion, multinucleated giant cell formation, collagen deposition, foam degradation, and angiogenesis.

Electrocatalytic glucose sensor.

High surface area platinum subjected to the appropriate electrical potential cycling regimes exhibits considerable electrocatalytic activity towards glucose oxidation. We have developed a special data processing method, the compensated net charge (CNC) method, to take advantage of the electrocatalytic activity of platinum. This method involves the determination of the net oxidation charge during one complete cycle of a cyclic voltammogram applied to the platinum electrode in a potentiodynamic mode. Under these conditions, the electrode response is very sensitive to glucose, completely insensitive to urea, and only moderately sensitive to amino acid concentration changes. Earlier work with other endogenous and exogenous potential co-reactants shows little interference. Data obtained in vitro and in vivo will be presented and discussed.

Expanded polytetrafluoroethylene as a microvascular graft: a study of four fibril lengths.

The utility for a prosthetic microvascular graft is well demonstrated, but previous studies have been inconclusive. Expanded polytetrafluoroethylene (Gore-Tex) has been most widely tested as a prosthetic graft. Polytetrafluoroethylene is composed of transverse nodules connected by long fibrils. This study evaluates the effect of fibril length on observed patency in a 1-mm inner-diameter system. Fibril lengths tested were 30, 60, 90, and 120 micron. One-hundred and sixty-three grafts were implanted in the abdominal aorta of Sprague-Dawley rats by a single surgeon using a standardized technique. No anticoagulants were used. Grafts were harvested at predetermined times and evaluated macroscopically, by scanning electron microscope, and by standard histology. The highest patency observed was 97.7 percent in the 90-micron fibril-length grafts. Fibril morphology also affected patency. Increased patency was associated with an amorphous fibril pattern. The graft functioned as a matrix for the formation of a pseudoartery, complete with monocell-thick intima and smooth-muscle media. A foreign-body reaction was observed in the 60-micron fibril-length graft only. Expanded polytetrafluoroethylene does show promise as a microvascular graft. Both fibril length and morphology affect observed patency.

The gastrostomy "button"--a simple, skin-level, nonrefluxing device for long-term enteral feedings.

In an effort to eliminate the common problems associated with gastrostomy tubes in children, we developed a silicone rubber gastrostomy "button" designed to replace the standard long latex tube. Easily inserted and self-retaining, the device remains practically flush with the skin. The intragastric portion is similar to a dePezzer catheter, and a one-way valve prevents reflux of gastric contents. Prototypes were evaluated in five children for a time period of 3 to 18 months. In two additional patients with esophageal stricture, the device was used as a temporary plug to maintain gastric stoma patency. Parents and nurses are pleased with the button's low profile, appearance, and ease to use. It is neither painful nor irritating, and there is no fear of dislodgement.

Effect of polyurethane morphology on blood coagulation.

A series of polyurethanes based on the hard segment MDI and soft segment PTMG were synthesized. The molecular weight of the PTMG was 730, 1000, and 2000, and ethylene diamine was used as chain extender. The fabrication process was varied so as to achieve the maximum disorder (nonequilibrium state) and maximum order, fully annealed. It was demostrated that the "quenched" non-equilibrium state reduces the rate of activation of the intrinsic systems, factor XII pathway, when compared to the fully annealed state. Platelet attachment is primarily affected by phase separation.

Surface characteristics of the cardiac prostheses in vivo.

The pseudoneointima (PNI) deposited onto a cardiac prosthesis surface reflects many factors of biocompatibility, surface morphology, flow distribution, design, animal's physiological condition, and duration. In the evaluation of any prosthesis, the PNI is one of the prime considerations from both material and functional standpoints. Historically, Dacron fabric has been used as an internal lining for cardiac prostheses. However, we have observed cracks on the Dacron fibers, fiber fracture, fiber protrusion, and poor attachment to the diaphragm, which can cause potentially disastrous complications. In addition, there are basic differences in the PNI formation on aldehyde-treated pericardium and natural aortic valves as compared to the Dacron fabric. 1) Minimal degeneration takes place on the chemically treated natural tissue compared with the fabtic surface. Intact cells on the tissue suggest a greater compatibility. In later specimens (13 and 24 days), there is active cell infiltration onto the pericardium structure with capillary formation. 2) The deposits on natural tissue are mostly fibrin, with minimum cellular involvement and a trend toward reduction in thickness. 3) Fibroblast cells are found on the natural tissue as early as 7 days but were not observed on the Dacron fabrics. Based on these findings, the Dacron fabric-covered diaphragm studied was not favorable for use in long-term implantation of cardiac prostheses.

Application of aldehyde treatments to cardiovascular devices.

Biolized natural and synthetic materials represent a new class of materials. Aldehyde treatment of natural tissue creates cross-links in the collagen molecules while retaining mechanical strength and collagen structure. Synthetic polymers can also be biolized by the addition of protein and aldehyde treatment. Cross-linked materials such as these are resistant to degradation by proteolytic enzymes. The procedure for the aldehyde treatment of natural tissue and protein polymer composites has been established, and in vivo and in vitro studies have demonstrated an improved blood compatibility. Long-term survival with TAH and LVAD implanted animals has shown the successful application of these materials without the use of anticoagulants. Pseudoneointima growth occurs on these surfaces, and results to date indicate growth stabilization within 2 wks of impalntation. Studies are currently underway to fully characterize the pseudoneointima formed on the biolized surfaces of cardiac prostheses.