Doctor of Philosophy (PhD) Orthoptics / The aim of this study was to evaluate the safety and efficacy of LASIK as a refractive surgical procedure, using a repeated measures design to assess satisfaction of patients who had LASIK and to correlate clinical outcomes with detailed measures of patient satisfaction to document long-term viability, monitor changes over time and patients’ functional abilities post-operatively. Method In the study 216 post-LASIK subjects were randomly selected from among patients who underwent simultaneous bilateral LASIK using the Chiron Technolas 217C plano-scan excimer laser with the Chiron ACS (Automated Corneal Shaper) and the Hansatome microkeratome. The subjects were recruited from within one centre, and the procedures were performed by any one of three surgeons. The study also included 100 non-LASIK subjects as a control group, to compare and differentiate ocular symptoms and visual difficulties between LASIK and non-LASIK patients. Clinical data documented included visual acuity, subjective refraction, record of glasses and/or contact lenses prescription, corneal topography with EyeSys and Orbscan, slit lamp examination, surgical details, and any pre-existing eye disease/conditions and previous surgery or injury that might prevent the subjects from achieving their desired visual outcome post-operatively. Subjective patient satisfaction evaluation of the treatment group was assessed by subjects completing a survey questionnaire at 3 months, 6 months, 12 months and 24 months post-operatively. The control group subjects completed a comparable questionnaire and were assessed at baseline and 3 months later. Because the control group subjects did not have any surgical alterations, it was unnecessary for them to have more than one follow-up. Results LASIK achieved relatively high patient satisfaction, with only a small number of dissatisfied patients. It was effective in correcting myopia, hyperopia and astigmatism. However, there was some persistent under-correction in myopic spherical and minus cylindrical refractive errors. Hyperopic spherical correction was less effective, as there were more under- as well as over-correction, and the plus cylindrical correction tended to be under-corrected. The LASIK subjects’ post-operative distance uncorrected visual acuity was not as good as their pre-operative best corrected visual acuity, but it did not significantly correlate with patient satisfaction. The findings were consistent with other studies and confirmed the concept that patient satisfaction is not unidimensional and is not related to outcome solely in terms of visual acuity and residual refractive errors. Other contributing factors included problems with glare, rating of unaided distance and near vision, ability to drive at night, change in ability to perform social/recreational, home and work activities, change in overall quality of life, amount of information given prior to surgery, rating of surgery success, and surgery outcome relative to pre-operative expectations. These variables demonstrated distinctive differences between subjects who were satisfied and dissatisfied. Conclusions The findings of this study are consistent with those of earlier studies. However, the repeated measures design and the comparisons between LASIK subjects and the control group revealed some new insights that were previously undocumented. LASIK achieved high patient satisfaction, and factors associated with satisfaction were predictable, but sources of dissatisfaction were more idiosyncratic and contributing factors were identified.

Doctor of Philosophy (PhD) Orthoptics / The aim of this study was to evaluate the safety and efficacy of LASIK as a refractive surgical procedure, using a repeated measures design to assess satisfaction of patients who had LASIK and to correlate clinical outcomes with detailed measures of patient satisfaction to document long-term viability, monitor changes over time and patients’ functional abilities post-operatively. Method In the study 216 post-LASIK subjects were randomly selected from among patients who underwent simultaneous bilateral LASIK using the Chiron Technolas 217C plano-scan excimer laser with the Chiron ACS (Automated Corneal Shaper) and the Hansatome microkeratome. The subjects were recruited from within one centre, and the procedures were performed by any one of three surgeons. The study also included 100 non-LASIK subjects as a control group, to compare and differentiate ocular symptoms and visual difficulties between LASIK and non-LASIK patients. Clinical data documented included visual acuity, subjective refraction, record of glasses and/or contact lenses prescription, corneal topography with EyeSys and Orbscan, slit lamp examination, surgical details, and any pre-existing eye disease/conditions and previous surgery or injury that might prevent the subjects from achieving their desired visual outcome post-operatively. Subjective patient satisfaction evaluation of the treatment group was assessed by subjects completing a survey questionnaire at 3 months, 6 months, 12 months and 24 months post-operatively. The control group subjects completed a comparable questionnaire and were assessed at baseline and 3 months later. Because the control group subjects did not have any surgical alterations, it was unnecessary for them to have more than one follow-up. Results LASIK achieved relatively high patient satisfaction, with only a small number of dissatisfied patients. It was effective in correcting myopia, hyperopia and astigmatism. However, there was some persistent under-correction in myopic spherical and minus cylindrical refractive errors. Hyperopic spherical correction was less effective, as there were more under- as well as over-correction, and the plus cylindrical correction tended to be under-corrected. The LASIK subjects’ post-operative distance uncorrected visual acuity was not as good as their pre-operative best corrected visual acuity, but it did not significantly correlate with patient satisfaction. The findings were consistent with other studies and confirmed the concept that patient satisfaction is not unidimensional and is not related to outcome solely in terms of visual acuity and residual refractive errors. Other contributing factors included problems with glare, rating of unaided distance and near vision, ability to drive at night, change in ability to perform social/recreational, home and work activities, change in overall quality of life, amount of information given prior to surgery, rating of surgery success, and surgery outcome relative to pre-operative expectations. These variables demonstrated distinctive differences between subjects who were satisfied and dissatisfied. Conclusions The findings of this study are consistent with those of earlier studies. However, the repeated measures design and the comparisons between LASIK subjects and the control group revealed some new insights that were previously undocumented. LASIK achieved high patient satisfaction, and factors associated with satisfaction were predictable, but sources of dissatisfaction were more idiosyncratic and contributing factors were identified.

Die subendotheliale myointimale Hyperplasie (MIH) stellt eine der Hauptursachen für die Ausbildung von Stenosen und Verschlüssen im Bereich von Anastomosen dar. Besondere Bedeutung hat die MIH in termino-lateralen Anastomosen. An der Entstehung der MIH sind hämodynamische Faktoren entscheidend beteiligt. Ausgehend von der Annahme, daß eine Veränderung der Anastomosenform die Hämodynamik beeinflussen kann, wurde in der vorliegenden Arbeit eine neue Anastomosenform, die femorocrurale Patchprothese (FCPP), entwickelt mit dem Ziel einer Optimierung der Strömungsverhältnisse im Anastomosenbereich. In einem hydrodynamischen Kreislaufmodell wurden elastische, transparente Silikonmodelle von termino-lateralen Anastomosen mit einem blutanalogen Newtonschen Fluid (Glycerol-Wasser-Gemisch) unter Simulation der femorocruralen Druckkurve pulsatil bei Variation der Strömungsbedingungen perfundiert. Die konventionellen und klinisch erprobten Anastomosenformen (termino-laterale Anastomose, Composite Bypass, Linton Patch, Miller Collar, Taylor Patch) wurden in vitro mit der FCPP-Anastomose und zwei Modifikation dieser Anastomosenform verglichen. Die Visualisierung des Strömungsfeldes wurde mit drei verschiedenen Methoden erreicht. Bei der farboptischen Methode wurde die Verteilung und Bewegung von Farbteilchen im Anastomosenbereich nach Injektion in das strömende Fluid mittels Video aufgezeichnet. Für die Ultraschalluntersuchung mittels hochauflösender farbcodierter Dopplersonographie (FKDS) wurde das Fluid mit Sephadex-Partikeln dotiert. Sämtliche Ultraschalluntersuchungen wurden ebenfalls mittels Video aufgezeichnet. Die Dopplerspektren korrespondierender Punkte in den Randzonen der Anastomosen wurden off-line der Fast Fourier Analyse (FFT) unterzogen und diese dreidimensional dargestellt. Die semiquantitative Analyse anhand der farboptischen Methode zeigte eine signifikante Verringerung bis Elimination MIH-assoziierter Strömungsphänomene in der FCPP-Anastomose und deren Modifikationen. Die Ausprägung der einzelnen Strömungsphänomene war abhängig von der Reynolds-Zahl und von dem Verhältnis von proximalem und distalem Stromzeitvolumen. Als Vorteil der FCPP erwies sich die Möglichkeit der Anpassung ihrer Form an die entsprechende Flußsituation durch Modifikation der Gabelform mit annähernd laminarer Strömung im gesamten Anastomosenbereich. Die FKDS bestätigte die Ergebnisse der farboptischen Methode. In der Peak-Systole und am Beginn der Diastole waren Rezirkulationszonen und Zonen niedriger Strömungsgeschwindigkeit in der FCPP am geringsten ausgeprägt oder nicht mehr nachweisbar (modifizierte FCPP). Der Vergleich der 3D-Darstellungen der FFT der Dopplerspektren zeigte niedrige Frequenzen und damit Flußgeschwindigkeiten und partiell eine Strömungsumkehr nahezu konstant in allen Anastomosenformen außer der FCPP und deren Modifikationen. In einer prospektiven Studie zum klinischen Einsatz der FCPP Anastomose wurden im Zeitraum von 6 / 1992 bis 7 / 1998 135 PTFE-Prothesenbypass-Rekonstruktionen mit distaler FCPP Anastomose bei 129 Patienten im klinischen Stadium III und IV der paVK analysiert. Die kumulativen primären und sekundären 1-, 2-, 3-, 4-, und 5-Jahres-Offenheitsraten nach Kaplan / Meier betrugen jeweils 63,0%, 44,9%, 35,7%, 33,1% und 27,6% bzw. 74,5%, 55,2%, 44,8%, 43,0% und 37,6%. Die kumulativen 1-, 3-, und 5-Jahres-Wahrscheinlichkeiten für den Erhalt der Extremität betrugen jeweils 86,8%, 79,2% und 77,5%. Eine Optimierung des Strömungsverhaltens innerhalb der Anastomosenregion ist in der FCPP derart möglich, daß der Anteil der für die Pathogenese der MIH ursächlichen Strömungsmuster minimiert wird. Diese Anastomose ist klinisch anwendbar und führt bei ausschließlicher Verwendung von ePTFE als Bypassmaterial im femorodistalen Bereich zu akzeptablen Langzeitergebnissen, die denen bei Anwendung von alternativ möglichen Venenpatchplastiken nicht nur vergleichbar, sondern teilweise überlegen sind. / The subendothelial myointimal hyperplasia (MIH) represents one of the main etiological factors in the formation of stenoses and occlusions of vascular anastomoses. MIH plays a role especially in termino-lateral anastomoses. Hemodynamic factors have a decisive impact on the development of MIH. Assuming that changes in the morphology of the anastomoses influence the hemodynamics, a novel anastomosis form, the femorocrural patch prosthesis (FCPP), was developed with the goal of optimizing the blood flow-dynamics within the anastomotic site. In a hydrodynamic circulation model, various elastic, transparent silicon phantoms of termino-lateral anastomoses were perfused with a Newton fluid blood analog (glycerol-water mixture) while simulating the femorocrural pressure curve in a pulsatile manner under variation of the flow conditions. The conventional and clinically tested anastomosis forms (termino-lateral anastomosis, composite bypass, Linton patch, Millar collar, Taylor patch) were compared with the FCPP-anastomosis and two modifications of the FCPP in vitro. The visualization of the flow velocity field was achieved using three different methods. By means of the color-optic method, the distribution and motion of color elements in the anastomotic area were video-recorded following injection in the flowing liquid. For the ultrasound examination with high resolution, color-coded Doppler sonography, the fluid was marked with Sephadex particles. All ultrasound examinations were also recorded on video. The corresponding doppler spektrum points in the marginal zones of the anastomosis were subjected to the Fast Fourier Transform (FFT) analysis off-line and then displayed three-dimensionally. The semiquantitative analysis using the color-optic method showed a significant decrease or elimination of MIH-associated current phenomena in the FCPP-anastomosis and its corresponding modifications. The intensity of singular flow phenomena was dependent upon the Reynolds-number and upon the relation of proximal to distal flow volume over time. The possibility to adapt the FCPP to the flow phenomena by modifying the bifurcated form and thereby achieving almost laminar flow in the complete anastomotic area proved to be advantageous. The color-coded Doppler sonography confirmed the results of the color-optic method. During peak systole and at the beginning of the diastole, recirculation zones and zones with low flow velocity were least intense in the FCPP or not detectable at all (in the modified FCPPs). The comparison between the FFT 3D-reconstructions from the Doppler spektrum showed low frequencies and thus flow velocities and a partial flow reversal almost constantly in all anastomosis forms except the FCPP and its modifications. In a prospective study on the clinical application of the FCPP anastomosis during the period of June 1992 to July 1998, 135 ePTFE prosthetic bypass reconstructions with distal FCPP anastomosis were analyzed in 129 patients suffering from peripheral arterial occlusive disease stages III and IV. The cumulative primary and secondary 1-, 2-, 3-, 4-, and 5-year patency rates calculated with the Kaplan / Meier method were 63.0%, 44.9%, 35.7%, 33.1%, and 27.6%, and 75.5%, 55.2%, 44.8%, 43.0% and 37.6%, respectively. The cumulative 1-, 3-, and 5-year probabilities for limb salvage were 86.8%, 79.2% and 77.5%, respectively. As a result of anastomotic engineering, FCPP optimizes the flow properties within the anastomosis region to such an extent that the pathogenetic role of flow disturbances is minimized. This anastomosis is clinically employable when using ePTFE as bypass material in femoro-distal vascular reconstruction and leads to acceptable long-term results that are not only comparable but sometimes superior to the results obtained when using alternative vein cuff techniques.

Einleitung: Primäres Ziel der Rekonstruktion des vorderen Kreuzbandes (VKB) ist die Verbesserung der Stabilität des Kniegelenkes, doch daran allein lässt sich das Behandlungsergebnis nicht beurteilen. Mit den Daten von 23 Patienten nach VKB-Plastik (4 Jahre p.o.) sollte diskutiert werden, welche Variablen noch geeignet sind, um den Behandlungserfolg zu bewerten. Ergebnisse und Diskussion: Die Kniefunktion im Alltag wurde in den Knie-Scores als gut oder besser beurteilt, die Bewertung beim Sport war etwas schlechter. Die KOS-Scores ADL und Sport haben sich für die Erfassung der subjektiven Zufriedenheit besonders geeignet. Im klinischen Befund gab es kaum Defizite. Die Gelenkbeweglichkeit und Stabilität des VKB (Lachman) sind die relevanten Beurteilungskriterien. Hinsichtlich der Sportfähigkeit war ein Rückgang in Sportarten mit höherer Kniegelenksgefährdung zu sehen. Nur 36,4 % der Patienten sind auf prätraumatischem Niveau aktiv. Die Sportfähigkeit dürfte jedoch für langfristige Evaluationen nicht von Interesse sein, da altersbedingte Veränderungen im Freizeitverhalten einen zunehmenden Einfluss haben. In einbeinigen sportmotorischen Tests, wie dem Nieder-Hoch-Sprung, zeigten sich auf der operierte Seite verlängerte Bodenkontaktzeiten. Dieser Test ist für die Beurteilung genauso geeignet wie der Einbeinweitsprung. Bei diesem war zwar kein Seitenunterschied, jedoch eine verkürzte Sprungweite gegenüber Kniegesunden zu finden. Bei den isokinetischen Messungen fanden sich persistierende Defizite der Extensoren (op. Bein) sowie bilaterale Veränderungen, verglichen mit dem Referenzwert. Ferner lagen auf der op. Seite verminderte Muskeldicken der Mm. vastus medialis et intermedius (knienah) vor. Die Werte der isokinetischen Messung wie der sonografischen Muskeldickenmessung stellen daher wichtige Indikatoren zur Bewertung des Muskelstatus dar. Untersuchungen wie EMG, Ganganalyse, Einbeinstandtest, Beinumfangsmessung, beidbeinige Sprünge und Beintapping ließen keine Defizite erkennen. Diese Verfahren können kaum einen Beitrag zur Einschätzung des Behandlungsergebnisses leisten. Es gab mehrere Hinweise auf bilaterale Veränderungen, daher ist bei vielen Tests der alleinige Seitenvergleich nicht ausreichend. Somit ist zu fordern, dass künftig zur Bewertung des Behandlungsergebnisses nach VKB-Plastik einheitliche Untersuchungsstandards angestrebt sowie Normwerte für diese Testverfahren geschaffen werden. / Introduction: The primary goal of anterior cruciate ligament (ACL) reconstruction is to improve knee joint stability; however, this factor alone is not enough in evaluating treatment results. With data from 23 patients (4 years post-op) after reconstruction of the ACL variables will be discussed as to which are well-suited in judging treatment success. Results and discussion: Knee joint function for activities of daily life (ADL) was rated by knee-scores as good or better; for sport activities the rating was somewhat worse. KOS scores for ADL and sport are well-suited for the conceived, subjective contentment. Clinical results show hardly any deficits. Joint range of motion and stability of the ACL (Lachman test) are relevant rating criteria. With regard to sport capability a reduction was seen in sports where a high risk for the knee joint was present. Only 36.4 % of the patients are at a „pre-trauma“-level. Long-term evaluation of sport capability is not of interest, since age-related changes in leisure activity are of increasing influence. By sport motor tests such as the one-leg drop-jump, an increase in ground contact time was seen. This test is just as well-suited for evaluation as the one-leg long jump. This test showed no side difference except for a shortened jumping distance in comparison to the healthy reference group. Isokinetic results reveal persistent deficits of the knee extensors (operated knee) as well as bilateral changes when compared to reference values. Furthermore, reduced muscle thickness of the Mm. vastus medialis et intermedius near the joint was seen. Isokinetic measurement values and sonographic muscle-thickness measurements represent important indicators when evaluating muscle status. Tests such as EMG, gait analysis, one-leg standing test, thigh-girth measurements, two legged jumps and leg-tapping do not reveal any deficits. These tests can hardly contribute to an evaluation of treatment results. There is much evidence of bilateral changes; therefore side comparisons alone are not adequate. It is therefore to encourage standardized examination tests as well as normal values when evaluating treatment results after ACL reconstruction.