京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第17866号 / 工博第3775号 / 新制||工||1577(附属図書館) / 30686 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 藤田 正治, 准教授 川池 健司 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Flow separation is a common fluid dynamics phenomenon that occurs within supersonic nozzles while operating at off-design pressures. Typically, off-design pressures result in a shock formation that leads to a non-uniformity of the exiting flow and creates flow separation and flow recirculation. So far, no effective solution has been presented to eliminate flow separation and increase the total performance of the nozzle. The purpose of this work is to investigate whether a Gurney flap may beneficially affect the exiting flow pattern. For a better understanding of the Gurney flap effect, this investigation used a supersonic nozzle geometry based on a previous study by Lechevalier [33]. Results from the tested cases showed a poor effect of the flap at high free-stream Mach number and lower pressure ratio. Simulations of different flap heights along with different parameters showed a slight increase of thrust.

No description available.

Cutaneous arterial blood supply to the temporal region was evaluated in 8 dogs and 8 cats. Dissection of 4 dog and 4 cat cadavers revealed the location of cutaneous branches of the superficial telnporaJ artery supplying the frontalis tnuscle and skin of the temporal region. The frontalis 1l1uscle is a thin muscle dorsal to the temporaJis muscle that extends cranially and rostral1y from the rostral border of the scutulU111 to the forehead and upper eyelid. Microangiography and subtraction radiography of the external carotid and superficial telnporal arteries were used in 4 dogs and 4 cats to determine arterial blood supply to the temporal region and frontalis muscle. A superficial temporal artery (ST A) flap was developed in 9 dogs [ group A (n=5), group B (n=4)]. Ligation of the superficial tetnporal artery in the control dogs (n=5), rendered flaps dependent on the subdermal plexus. Dogs in group A (n=5) and the control group (n=5) had flap lengths that extended to the contralateral eye, while group B (n=4) flaps extended to the contralateral zygomatic arch. A11 flap widths were equivalent to the width of the zygomatic arch in the individual dog. Mean length of surviving tissue (mean survival length) (+/- SD) of control flaps was 7.0 (0.6) ern, compared with experimental flaps, group A 9.) (0.8) em and group B 10.4 0.1) cm. Mean survival percentage area of control flaps was 73.5 (7.4) %, compared with experimental flaps, group A 93.1 (7.5) 0/0 and group B 69.1 (4.5) 0/0. The mean survival length of control and experimental flaps was significantly different (P < 0.05). There was no significant difference between survival lengths of the experimental groups. / Master of Science

Background: Conjunctival pedicle flaps are one of the most frequently employed surgical interventions used to address a variety of sight threatening corneal diseases in veterinary ophthalmic practice. Securing the conjunctiva to the cornea is typically achieved through suturing, which is technically challenging and can result in prolonged surgical times, increased corneal edema, increased scar tissue, foreign body reaction, suture abscess and dehiscence. In human ophthalmology, a number of sutureless techniques to affix ocular tissues are being explored. Specifically, these approaches include synthetic tissue adhesives, bioadhesives, and hydrogel sealants. The proposed advantages of adhesives over suture, include reduced operative times, watertight seals, decreased foreign-body sensation and inflammation, faster healing times and tissue regeneration with original architecture restoration. Objective. To evaluate the maximum tensile force a conjunctival pedicle flap is able to withstand with respect to different fixation methods, i.e., Tisseel® fibrin glue, ethyl cyanoacrylate adhesive, ReSure® hydrogel sealant, or 8-0 VICRYL suture. Animals Studied. Ex-vivo porcine globes Procedures. Following a 500-micron restricted depth lamellar keratectomy, conjunctival pedicle flaps were dissected and secured to corneal defects with either the bioadhesive Tisseel®, or the synthetic adhesives ReSure®, ethyl cyanoacrylate, or 8-0 VICRYL® suture. Harvested corneoconjunctival flap interfaces were clamped to an accelerometer and potentiometer device, and loaded under video surveillance until the point of failure. Peak load at failure was determined for each test and used to compare between sample types. Results. 40 flaps underwent tensile force testing, with 6 being omitted for dehiscence prior to tensile testing. Of the 34 tests included in analysis, 10 conjunctival flaps were secured with suture, 10 with cyanoacrylate, 8 with ReSure® hydrogel sealant, and 6 with Tisseel® fibrin glue. A significant increase in maximum withstood tensile force was recorded between sutured flap fixation when compared with cyanoacrylate glue (p=0.02474), ReSure® hydrogel sealant (p= 0.00000), and Tisseel® fibrin glue (p= 0.00002). Cyanoacrylate fixation was significantly stronger when compared with ReSure® hydrogel sealant and Tisseel fibrin glue (p=0.01194 and 0.01798 respectively). There was no significant difference in adhesion strength between ReSure® hydrogel sealant and Tisseel® fibrin glue (p=0.95675). Conclusions. Conjunctival pedicle flap fixation using 8-0 VICRYL® suture fixation was able to withstand significantly greater maximum tensile force application in comparison with the ReSure®, Tisseel®, or cyanoacrylate adhesives. / Master of Science / Conjunctival pedicle flaps are one of the most frequently employed surgical interventions to address sight threatening corneal disorders in companion animals. Due to its redundant nature and close proximity to the corneal surface, conjunctival tissue is readily available for grafting to the cornea. It is surgically dissected to appropriate size and repositioned over the corneal defect where it effectively aids in healing through direct provision of structural support and indirectly via its rich blood supply. Securing the conjunctiva to cornea is typically achieved through suturing, which is technically challenging and can result in prolonged surgical times, increased corneal edema, increased scar tissue, foreign body reaction, abscess and dehiscence. In human ophthalmology, a number of sutureless techniques to affix ocular tissues are being explored. Specifically, these approaches include synthetic tissue adhesives, bioadhesives, and hydrogel sealants. The proposed advantages of tissue adhesives over suture, include reduced operation times, watertight closures, decreased foreign-body reaction and inflammatory response, faster healing times and increased ability to induce regeneration of the original tissue architecture. The purpose of this study was to evaluate the maximum tensile force a corneoconjunctial pedicle flap is able to withstand with respect to four different fixation methods, 40 ex-vivo porcine globes underwent conjunctival pedicle flap procedures. Each pedicle flap was secured to cornea with either 8-0 Vicryl® suture, Tisseel®, ethyl cyanoacrylate, or ReSure®. After harvesting from the globe, the corneoconjunctival unions were clamped to an accelerometer and potentiometer device, and loaded under video surveillance until the point of failure. The peak load was determined for each test and used to compare between sample types.

O omento maior tem sido utilizado com grande eficácia na medicina e em cirurgias torácicas, urogenitais, neurológicas, vasculares e respiratórias por sua natureza única, versátil e suas propriedades de imunidade, drenagem, adesão, vascularização e hemostasia bem conhecidas. Tem sido aplicado em humanos, como uma importante fonte de vascularização para áreas distantes, como flap pediculado ou livre, dentre elas, tórax, cabeça, pescoço e porções proximais de extremidades. As pesquisas com flap pediculado de omento maior, na cirurgia veterinária como indutor angiogênico e imunogênico são poucas, entretanto, suas propriedades de adesão e drenagem são conhecidas e utilizadas em procedimentos cirúrgicos com excelentes resultados. O objetivo desta pesquisa foi criar retalho pediculado de omento maior, mensurando o comprimento durante as etapas de criação e avaliando a possibilidade de alcance para ossos longos (fêmur, tíbia, úmero e rádio e ulna) através de túnel subcutâneo. Foram utilizados 30 cadáveres de cães frescos com 10 a 30 quilos de massa corpórea, sem discriminação de idade, sexo ou raça. Os resultados foram satisfatórios e 100% dos animais alcançaram a metáfise distal dos ossos avaliados. A média de comprimento do omento em camada dupla, dos 30 animais avaliados foi de 30,87 cm, da camada simples de 54,37 cm e do flap em L 92,7 cm. Com a extensão máxima do omento foi possível alcançar as metáfises distais de todos os ossos propostos (fêmur, tíbia/fíbula, úmero e rádio/ulna), com comprimento médio excedente de 29,87 cm para fêmur, 20,73 cm para tíbia/fíbula, 25,13 cm para úmero e 16,27 cm para rádio/ulna As variáveis peso flap em L avaliadas estatisticamente apresentaram correlação positiva moderada nos grupos apresentados. Concluiu-se que em cães é possível levar o flap pediculado de omento maior através de túnel subcutâneo para metáfise distal de ossos longos sem tensão e que quanto maior o peso do animal, maior o comprimento do flap em L dos animais avaliados em cada grupo. / The greater omentum has been successfully used in human medicine in different surgical approaches such as thoracic, urogenital, neurological, vascular, and respiratory. The high usefulness of omentum is due to its singular nature and versatility, as well as its known different properties such as immunologic, drainage, adhesion, angiogenic and haemostatic. It has been used in human medicine such as a pediculated or free flap as an important vascular inductor for different areas. Among the sites that it has been used to increase blood flow by its angiogenic properties, little the thorax, head and neck, and proximal and distal extremities may be sited. Research on immunogenic and angiogenics inductor properties of the flap in Veterinary Medicine have been made, however, its adhesive and draining properties are well known and have been used with excellent results in surgery. An experimental study to obtain a pediculated flap of greater omentum and conduct it as far as possible through a subcutaneous tunnel in order to reach long bones (femur, tibia, umero, radius and ulna). Was designed during the experiment, the obtained different flaps were measured and the possibility of reaching proximal to distal long bone sites was checked. For the experiment 30 fresh body (10 to 30 kg of corporal weight) from dead dogs without predilection to age, or sex were used. Animals of all breeds were included except condrosdistrophics breeds. In addition, dogs with signs of abdominal surgery, abdominal adherences, or other anatomic dysfunctions of the greater omentum were excluded from the experiment. The results were satisfactor and in 100% of the cases the flap reached the distal half of the evaluated bones. The averages of the different flap lengths were: 30.87 cm when double layer was used; 54.37 cm in simple layer; and 92.7 cm when the flap was made in an L shape. With the largest extension of the omentum, it was possible to reach the distal metaphises of all studied bones (femur, tibia/fibula, humerus, and radius/ulna). The exceeding length average was 29.87 cm for the femur, 20.73 cm for the tibia/fibula, 25.13 cm for the humerus, and 16.27 cm for the radius/ulna. The variation body-weight-flap variety statistically evaluated showed moderate positive correlation on the presented groups. In conclusion, the omentum pediclulated flap may be passed through the subcutaneous tunnel until the distal metaphisis of the long bones of dogs without tension. Animals with carger bodyl weight have the largest length of the L- shaped flap.

Os objetivos deste estudo foram desenvolver um modelo experimental e avaliar o período bem como a viabilidade de retalhos cutâneos pré-fabricados com área cutânea de 100cm2 em parede abdominal lateral em coelhos. Os retalhos cutâneos foram confeccionados através da implantação direta de vasos gastroepiplóicos em arco com fluxo contínuo abaixo do subcutâneo da parede lateral em coelhos. Foram utilizados 18 animais da linhagem de coelhos New Zealand divididos em três Grupos: Grupo I (grupo controle), sem implantação de vasos gastroepiplóicos, e Grupo II e Grupo III, nos quais foram realizados os implantes de vasos gastroepiplóicos em arco no subcutâneo da parede abdominal lateral dos animais, os quais foram submetidos posteriormente a cirurgia para confecção de retalho axial, pediculado exclusivamente nos vasos gastroepiplóicos transpostos. O período entre a primeira cirurgia e a segunda foi de duas semanas no Grupo II e seis semanas no Grupo III. Quatorze dias após a segunda cirurgia os animais foram sacrificados e os retalhos avaliados. Nos animais do Grupo I, controle, foi observado 100% de área de necrose no tecido descolado, não preservando conexão vascular com o mesmo, e suturado novamente no leito original; nos animais do Grupo II foi observada área de necrose média de 56,83% e nos animais do Grupo III, ausência total de necrose nos retalhos. Amostras dos retalhos dos animais dos Grupos II e III foram avaliados histologicamente através de protocolo padrão para coloração por hamatoxilina-eosina e através de estudo imunohistoquímico para avaliação de viabilidade do tecido através da quantificação da atividade de divisão celular, considerando índice de células marcadas para o Antígeno Nuclear de Células em Ploriferação (iPCNA) como parâmetro. Foi observado aumento significante no iPCNA (p<0,01, teste bicaudal de Mann-Whitney) entre os Grupos II e III, com índice mais alto no Grupo III; a avaliação da coloração por hematoxilina-eosina confirmam a maior viabilidade dos retalhos do Grupo III. O estudo demonstra a possibilidade de criar e transferir um pedículo vascular em arco para o subcutâneo e, depois de certo tempo, confeccionar e transpor um retalho com dimensões consideráveis cuja circulação seja exclusiva deste novo pedículo. Este estudo traz informações adicionais para elaboração de retalhos pré-fabricados microcirúrgicos ou em ilha para o reparo de defeitos complexos que precisam de grandes áreas de cobertura cutânea e pedículos longos, com mínima morbidade à área doadora. / The aim of this study was to develop an experimental model and to evaluate the period as well as the viability of prefabricated cutaneous flaps with a cutaneous area of 100cm2 in lateral abdominal wall in rabbits. The cutaneous flaps were made through the direct implantation of gastroepiploic vessels in arch with flow-through below the subcutaneous of the lateral wall in rabbits. Eighteen animals of the New Zealand rabbits lineage were used divided in three Groups: Group I (control group), without implantation of gastroepiploic vessels, and Group II and Group III, which the implant of gastroepiploic vessels was accomplished in arch in the subcutaneous of the lateral abdominal wall of the animals. These animals were submitted to surgery later for making of axial flap, exclusively based in the transposed gastroepiploic vessels. The period between the first surgery and the second one was of two weeks in the Group II and six weeks in the Group III. Fourteen days after the second surgery the animals were sacrificed and the flaps evaluated. In Group I animals, control, it was observed 100% of necrosis area in the detached skin portion that was sutured again at the original bed, not preserving vascular connection with the local tissue; in the animals of the Group II an average necrotic area of 56,83% was observed and in the animals of the Group III, total absence of necrosis in the flaps. Samples of flaps tissue from the animals of the Groups II and III were evaluated through standard histological hamatoxilin-eosin protocols and imunohistochemical protocol for evaluation of tissue viability through the activity of cellular division, considering the index of Proliferating cell nuclear antigen (iPCNA) marked cells. It was observed significant increase on the iPCNA (p<0,01, two-tailed Mann-Whitney test) between the Groups II and III, with higher index in the Group III; the standard hematoxilin-eosin evaluation confirm the better viability of the flaps from the Group III. The study demonstrates the possibility to create and transfer an arch vascular pedicle to subcutaneous and, after certain time, to make and to transpose a flap with considerable dimensions which circulation comes from this new pedicle. This study brings additional information for elaboration of prefabricated microsurgical or island flaps for repair of complex defects that need great areas of skin covering and long pedicles, with low morbosity to the donor area.

Os objetivos deste estudo foram desenvolver um modelo experimental e avaliar o período bem como a viabilidade de retalhos cutâneos pré-fabricados com área cutânea de 100cm2 em parede abdominal lateral em coelhos. Os retalhos cutâneos foram confeccionados através da implantação direta de vasos gastroepiplóicos em arco com fluxo contínuo abaixo do subcutâneo da parede lateral em coelhos. Foram utilizados 18 animais da linhagem de coelhos New Zealand divididos em três Grupos: Grupo I (grupo controle), sem implantação de vasos gastroepiplóicos, e Grupo II e Grupo III, nos quais foram realizados os implantes de vasos gastroepiplóicos em arco no subcutâneo da parede abdominal lateral dos animais, os quais foram submetidos posteriormente a cirurgia para confecção de retalho axial, pediculado exclusivamente nos vasos gastroepiplóicos transpostos. O período entre a primeira cirurgia e a segunda foi de duas semanas no Grupo II e seis semanas no Grupo III. Quatorze dias após a segunda cirurgia os animais foram sacrificados e os retalhos avaliados. Nos animais do Grupo I, controle, foi observado 100% de área de necrose no tecido descolado, não preservando conexão vascular com o mesmo, e suturado novamente no leito original; nos animais do Grupo II foi observada área de necrose média de 56,83% e nos animais do Grupo III, ausência total de necrose nos retalhos. Amostras dos retalhos dos animais dos Grupos II e III foram avaliados histologicamente através de protocolo padrão para coloração por hamatoxilina-eosina e através de estudo imunohistoquímico para avaliação de viabilidade do tecido através da quantificação da atividade de divisão celular, considerando índice de células marcadas para o Antígeno Nuclear de Células em Ploriferação (iPCNA) como parâmetro. Foi observado aumento significante no iPCNA (p<0,01, teste bicaudal de Mann-Whitney) entre os Grupos II e III, com índice mais alto no Grupo III; a avaliação da coloração por hematoxilina-eosina confirmam a maior viabilidade dos retalhos do Grupo III. O estudo demonstra a possibilidade de criar e transferir um pedículo vascular em arco para o subcutâneo e, depois de certo tempo, confeccionar e transpor um retalho com dimensões consideráveis cuja circulação seja exclusiva deste novo pedículo. Este estudo traz informações adicionais para elaboração de retalhos pré-fabricados microcirúrgicos ou em ilha para o reparo de defeitos complexos que precisam de grandes áreas de cobertura cutânea e pedículos longos, com mínima morbidade à área doadora. / The aim of this study was to develop an experimental model and to evaluate the period as well as the viability of prefabricated cutaneous flaps with a cutaneous area of 100cm2 in lateral abdominal wall in rabbits. The cutaneous flaps were made through the direct implantation of gastroepiploic vessels in arch with flow-through below the subcutaneous of the lateral wall in rabbits. Eighteen animals of the New Zealand rabbits lineage were used divided in three Groups: Group I (control group), without implantation of gastroepiploic vessels, and Group II and Group III, which the implant of gastroepiploic vessels was accomplished in arch in the subcutaneous of the lateral abdominal wall of the animals. These animals were submitted to surgery later for making of axial flap, exclusively based in the transposed gastroepiploic vessels. The period between the first surgery and the second one was of two weeks in the Group II and six weeks in the Group III. Fourteen days after the second surgery the animals were sacrificed and the flaps evaluated. In Group I animals, control, it was observed 100% of necrosis area in the detached skin portion that was sutured again at the original bed, not preserving vascular connection with the local tissue; in the animals of the Group II an average necrotic area of 56,83% was observed and in the animals of the Group III, total absence of necrosis in the flaps. Samples of flaps tissue from the animals of the Groups II and III were evaluated through standard histological hamatoxilin-eosin protocols and imunohistochemical protocol for evaluation of tissue viability through the activity of cellular division, considering the index of Proliferating cell nuclear antigen (iPCNA) marked cells. It was observed significant increase on the iPCNA (p<0,01, two-tailed Mann-Whitney test) between the Groups II and III, with higher index in the Group III; the standard hematoxilin-eosin evaluation confirm the better viability of the flaps from the Group III. The study demonstrates the possibility to create and transfer an arch vascular pedicle to subcutaneous and, after certain time, to make and to transpose a flap with considerable dimensions which circulation comes from this new pedicle. This study brings additional information for elaboration of prefabricated microsurgical or island flaps for repair of complex defects that need great areas of skin covering and long pedicles, with low morbosity to the donor area.

O omento maior tem sido utilizado com grande eficácia na medicina e em cirurgias torácicas, urogenitais, neurológicas, vasculares e respiratórias por sua natureza única, versátil e suas propriedades de imunidade, drenagem, adesão, vascularização e hemostasia bem conhecidas. Tem sido aplicado em humanos, como uma importante fonte de vascularização para áreas distantes, como flap pediculado ou livre, dentre elas, tórax, cabeça, pescoço e porções proximais de extremidades. As pesquisas com flap pediculado de omento maior, na cirurgia veterinária como indutor angiogênico e imunogênico são poucas, entretanto, suas propriedades de adesão e drenagem são conhecidas e utilizadas em procedimentos cirúrgicos com excelentes resultados. O objetivo desta pesquisa foi criar retalho pediculado de omento maior, mensurando o comprimento durante as etapas de criação e avaliando a possibilidade de alcance para ossos longos (fêmur, tíbia, úmero e rádio e ulna) através de túnel subcutâneo. Foram utilizados 30 cadáveres de cães frescos com 10 a 30 quilos de massa corpórea, sem discriminação de idade, sexo ou raça. Os resultados foram satisfatórios e 100% dos animais alcançaram a metáfise distal dos ossos avaliados. A média de comprimento do omento em camada dupla, dos 30 animais avaliados foi de 30,87 cm, da camada simples de 54,37 cm e do flap em L 92,7 cm. Com a extensão máxima do omento foi possível alcançar as metáfises distais de todos os ossos propostos (fêmur, tíbia/fíbula, úmero e rádio/ulna), com comprimento médio excedente de 29,87 cm para fêmur, 20,73 cm para tíbia/fíbula, 25,13 cm para úmero e 16,27 cm para rádio/ulna As variáveis peso flap em L avaliadas estatisticamente apresentaram correlação positiva moderada nos grupos apresentados. Concluiu-se que em cães é possível levar o flap pediculado de omento maior através de túnel subcutâneo para metáfise distal de ossos longos sem tensão e que quanto maior o peso do animal, maior o comprimento do flap em L dos animais avaliados em cada grupo. / The greater omentum has been successfully used in human medicine in different surgical approaches such as thoracic, urogenital, neurological, vascular, and respiratory. The high usefulness of omentum is due to its singular nature and versatility, as well as its known different properties such as immunologic, drainage, adhesion, angiogenic and haemostatic. It has been used in human medicine such as a pediculated or free flap as an important vascular inductor for different areas. Among the sites that it has been used to increase blood flow by its angiogenic properties, little the thorax, head and neck, and proximal and distal extremities may be sited. Research on immunogenic and angiogenics inductor properties of the flap in Veterinary Medicine have been made, however, its adhesive and draining properties are well known and have been used with excellent results in surgery. An experimental study to obtain a pediculated flap of greater omentum and conduct it as far as possible through a subcutaneous tunnel in order to reach long bones (femur, tibia, umero, radius and ulna). Was designed during the experiment, the obtained different flaps were measured and the possibility of reaching proximal to distal long bone sites was checked. For the experiment 30 fresh body (10 to 30 kg of corporal weight) from dead dogs without predilection to age, or sex were used. Animals of all breeds were included except condrosdistrophics breeds. In addition, dogs with signs of abdominal surgery, abdominal adherences, or other anatomic dysfunctions of the greater omentum were excluded from the experiment. The results were satisfactor and in 100% of the cases the flap reached the distal half of the evaluated bones. The averages of the different flap lengths were: 30.87 cm when double layer was used; 54.37 cm in simple layer; and 92.7 cm when the flap was made in an L shape. With the largest extension of the omentum, it was possible to reach the distal metaphises of all studied bones (femur, tibia/fibula, humerus, and radius/ulna). The exceeding length average was 29.87 cm for the femur, 20.73 cm for the tibia/fibula, 25.13 cm for the humerus, and 16.27 cm for the radius/ulna. The variation body-weight-flap variety statistically evaluated showed moderate positive correlation on the presented groups. In conclusion, the omentum pediclulated flap may be passed through the subcutaneous tunnel until the distal metaphisis of the long bones of dogs without tension. Animals with carger bodyl weight have the largest length of the L- shaped flap.

Abstract This thesis evaluated the factors affecting bone flap survival and bone flap resorption after primary cranial reparation surgery, cranioplasty, conducted to repair a cranial bone defect with an autologous cryopreserved bone flap. Emphasis is put on the predictors, progression, and definition of an important yet poorly understood postoperative complication, bone flap resorption. Study I assessed the rates and predictors of bone flap removal and bone flap resorption in a Finnish retrospective multicentre setting. 40% of patients developed complications of whom half required bone flap removal. Bone flap resorption and surgical site infections were the underlying cause in 90% of bone flap removal surgeries. The prevalence of both surgical site infections and bone flap resorption was 9%. In summary, young age was found to predict bone flap resorption and smoking predisposed patients to infections requiring bone flap removal. Study II applied computed tomography-based volumetry to evaluate the prevalence of subclinical bone flap resorption and to monitor its progression. In the follow-up, 90% of patients were found to have decreased bone flap volumes indicating varying degrees of resorption. However, the progression of bone flap resorption as a function of follow-up time was non-linear on the cohort level, and thus routine radiological follow-up seems unjustified. Most bone flaps do not appear to resorb enough to require removal even in the long-term follow-up. Study III addressed the unclarity in the definition of bone flap resorption. The computed tomography-based Oulu Resorption Score was developed to standardise the interpretation of radiological bone flap resorption and to guide follow-up interventions. The score values range from 0 to 9 with increasing values implying more severe bone flap resorption. Coupled with radiological evaluation conducted by independent neurosurgeons, an Oulu Resorption Score of ≥5 was defined to be clinically relevant. Further, the scores were divided into four grades based on the recommended follow-up procedures. Grades 0 (score 0) and I (scores 1 to 4) require no additional follow-up, but those with a grade II (score 5 to 8) or III (score 9) should be referred to neurosurgical consultation with reoperation considered at least in cases of grade III bone flap resorption. / Tiivistelmä Tässä väitöstyössä selvitettiin potilaan omalla kylmäsäilytetyllä luuistutteella tehtyjen kallon luupuutosten ensikertaisten korjausleikkausten tuloksiin vaikuttavia tekijöitä. Erityisesti tarkasteltiin luuistutteen liukenemisen, erään tärkeän, joskin heikosti ymmärretyn komplikaation ennustavia tekijöitä, etenemistä ja määritelmää. Tutkimuksessa I selvitettiin luuistutteen poiston ja liukenemisen yleisyyttä ja näihin vaikuttavia tekijöitä suomalaisessa takautuvassa monikeskusaineistossa. Potilaista 40 %:lle kehittyi komplikaatio. Komplikaatioista puolet johti istutteen poistoon. Luuistutteen liukeneminen ja leikkausalueinfektiot muodostivat 90 % poistoon johtaneista komplikaatioista. Sekä infektioiden että istutteen liukenemi¬sen esiintyvyys oli 9 %. Nuori ikä altisti istutteen liukenemiselle ja tupakointi leikkausalueinfektiolle. Tutkimuksessa II sovellettiin tietokonetomografiaan perustuvaa tilavuusmittausta luuistutteen oireettoman liukenemisen esiintyvyyden ja etenemistaipumuksen selvittämiseksi. Seurannassa 90 %:lla potilaista todettiin alentunut luuistutteen tilavuus viitaten asteeltaan vaihtelevaan istutteen liukenemiseen. Koko tutkimusjoukon tasolla istutteiden liukeneminen ei kuitenkaan edennyt lineaarisesti seuranta-ajan funktiona, joten rutiininomainen seuranta kuvantamistutkimuksin ei vaikuta perustellulta. Suurin osa luuistutteista liukeni niin vähän, ettei uutta leikkausta tarvittu pitkässäkään seurannassa. Tutkimuksessa III käsiteltiin luuistutteen liukenemisen nykyisellään epäselvää määritelmää ja kehitettiin uusi tietokonetomografiaan perustuva pisteytysjärjestelmä (Oulu resorption score) tarkoituksena vakioida radiologisten luuistutteen liukenemislöydösten tulkinta ja ohjata hoitolinjan valintaa. Pisteytysarvot vaihtelevat välillä 0-9. Kasvava arvo kuvaa luuistutteen liukenemisen vaikeusasteen kasvua. Luokitus yhdistettiin riippumattomien neurokirurgien radiologisiin arvioihin, joiden perusteella pistemäärä ≥5 määriteltiin kliinisesti merkitykselliseksi. Pistemäärät jaettiin neljään luokkaan suositeltujen jatkotoimenpiteiden mukaisesti. Luokkia 0 (0 pistettä) ja I (1–4 pistettä) vastaava luuistutteen liukeneminen ei vaadi jatkotoimenpiteitä. Luokkia II (5–8 pistettä) ja III (9 pistettä) vastaavasta luuistutteen liukenemisesta suositellaan konsultoitavan neurokirurgia. Uusintaleikkausta suositellaan harkittavan ainakin luokan III tapauksissa.