No description available.

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No description available.

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.

In dieser Arbeit wird das Revisionsverhalten kanülierter, fenestrierter Pedikelschrauben evaluiert. Dies erfolgt zum einen anhand von Messungen des Drehmoments bei dem Entfernen von Pedikelschrauben aus osteoporotischen Wirbelkörpern eines Kadermodells. Hierbei werden Werte nicht zementierter und zementierter, kanülierter Pedikelschrauben erhoben, verglichen und ausgewertet. Während der Schraubenexplantation werden etwaig auftretende Rotationsbewegungen des Zements im Wirbelkörper radiografisch detektiert. Darüber hinaus wird das Revisionsverhalten kanülierter, fenestrierter Pedikelschrauben nach Zementaugmentation in vivo anhand monozentrisch, retrospektiv erhobener Patientenbeispiele aus dem klinischen Alltag beurteilt. Im Rahmen der Drehmomentmessungen bei Entfernung der kanülierten, fenestrierten Pedikelschrauben nach vorangeganger Zementierung konnte keine Destruktion des Wirbelkörpers beobachtet werden. Auch in den untersuchten Fallbeispielen des klinischen Alltags konnten die zementaugmentierten Pedikelschrauben komplikationslos entfernt werden.

UA Open Access Publishing Fund / Background: Atlantoaxial surgical fixation is widely employed treatment strategy for a myriad of pathologies affecting the stability of the atlantoaxial joint. The most common technique used in adults, and in certain cases in children, involves a posterior construct with C1 lateral mass screws, and C2 pars or pedicle screws. This technical note aims to provide a step‑by‑step guide to this procedure using cadaveric and fluoroscopic images. Methods: An embalmed, human, cadaveric, specimen was used for this study. The subject did not have obvious occipital‑cervical pathology. Dissections and techniques were performed to mimic actual surgical technique. Photographs were taken during each step, and the critical aspects of each step were highlighted. Fluoroscopic images from a real patient undergoing C1/C2 fixation were also utilized to further highlight the anatomic‑radiographic relationships. This study was performed without external or industry funding. Results: Photographic and radiographic pictures and drawings are presented to illustrate the pertinent anatomy and technical aspects of this technique. The nuances of each step, including complication avoidance strategies are also highlighted. Conclusions: Given the widespread utilization of this technique, described step‑by‑step guide is timely for surgeons and trainees alike.

A inserção do parafuso pedicular cervical é um procedimento cirúrgico tecnicamente desafiador. Assim, o amplo conhecimento da morfologia das vértebras cervicais, particularmente do pedículo, é essencial para minimizar o risco de ferimentos graves a estruturas neurovasculares. O objetivo deste estudo foi conduzir uma avaliação detalhada de exames de tomografia computadorizada (TC) na população brasileira do ponto de entrada, trajetória, e dimensões dos pedículos da coluna cervical. Duzentos pacientes consecutivos foram retrospectivamente avaliados utilizando a TC da coluna cervical, com a reconstrução da imagem de cada vértebra no plano axial com 2 mm, e no plano sagital com 3 mm. Os parâmetros no plano axial incluíram a espessura pedicular (EP), o comprimento pedicular axial (CPA), o ângulo pedicular transverso (APT) e a distância do ponto de entrada ao ângulo entre a lâmina e o processo espinhoso (DPE). As medidas no plano sagital envolveram a altura pedicular (AP) e o ângulo pedicular sagital (APS). A EP e AP média são menores nos pacientes do sexo feminino do que nos pacientes do sexo masculino em todas as vertebras cervicais, porém não houve diferença significativa do APT entre os sexos. O APS variou de 15,2° a 23,7°. Os valores médios do CPA e DPE apresentaram uma tendência a diminuir de proximal para distal na coluna cervical. A EP encontrada foi menor que 4 mm em 7,5% dos pacientes do sexo masculino (C3) e em 25% dos pacientes do sexo feminino (C3), e menores que 4,5 mm em 20% dos pacientes do sexo masculino (C3) e em 66% dos pacientes do sexo feminino (C3). A confiabilidade intra e interobservador foram muito boas para a medida tomográfica da EP, e boa para a AP. Para o CPA, a confiabilidade intraobservador foi boa, porém a confiabilidade interobservador variou de moderada a boa. Considerando o APT e APS, a confiabilidade intraobservador foi boa, mas a confiabilidade interobservador moderada para o APT e fraca para o APS. As medidas do DPE evidenciaram fraca confiabilidade intraobservador e fraca ou moderada confiabilidade interobservador. Nossos resultados apresentaram tendência similar aos de estudos prévios, no entanto a frequência de pacientes com a EP < 4,5 mm em nossa população é maior, sugerindo um risco aumentado durante a tentativa de realizar a técnica transpedicular / Pedicular screw insertion is a technically challenged surgical procedure. Thus, extensive knowledge of the morphology of the cervical vertebra, primarily the pedicle, is crucial to reduce severe damage to neurovascular structures. The goal of this study was to conduct a detailed computed tomography (CT) assessment in the Brazilian population of the screw starting point, trajectory, and dimensions of pedicle in the cervical spine. Two hundred consecutive patients were retrospectively evaluated using cervical spine CT, with imaging reconstruction of each cervical vertebra in the axial plane with 2mm, and in sagittal reconstructions with 3mm. Parameters in axial plane included the pedicle width (PW), pedicle axis length (PAL), pedicle transverse angle (PTA), and the distance from the entry point to the point between the lamina and spinous process (DEP). Measurements in the sagittal plane involved the pedicle height (PH) and the pedicle sagittal angle (PSA). The mean PW and PH were smaller in females than in males in all cervical vertebrae, but there were no significant differences of PTA among genders. PSA ranged from 15.2° to 23.7°. Mean values of PAL and DEP had a tendency to decrease from the proximal to distal cervical vertebrae. PW was <4 mm in 7.5% of men (C3) and 25% of women (C3), and <4.5 mm in 20% (C3 male) and 66% (C3 female). The intra- and inter-observer reliability were very good for the tomographic measurement of PW, and good for PH. For PAL, the intraobserver reliability was good, but the interobserver reliability varied from moderate to good. Considering PTA and PSA, the intraobserver reliability was good, but the interobserver reliability moderate for PTA and poor or fair for PSA. DEP measurements showed poor intraobserver reliability, and poor or moderate interobserver reliability. Our results presented similar trend of previous studies, but the frequency of patients with PW <4.5 mm in our population is higher, suggesting an increased risk during the attempting of transpedicular screw technique

Foi realizado estudo experimental, utilizando-se vértebra de suínos, para o estudo da influência da técnica de perfuração do pedículo vertebral na resistência ao arrancamento dos implantes. A técnica de perfuração com broca seguida de macheamento do canal pedicular (técnica 1) foi individualmente comparada com as demais: perfuração com broca sem macheamento do canal pedicular (técnica 2), perfuração com fio de Kirschner com macheamento do canal pedicular (técnica 3), perfuração com sonda sem macheamento do canal pedicular (técnica 4). Três grupos experimentais foram utilizados de acordo com a preparação do orifício. O grupo I comparou a técnica 1 com a técnica 2, no qual foi estudado a influência do macheamento no canal do pedículo. O grupo II comparou a técnica 1 com a técnica 3, no qual foi estudado a influência no modo de preparo do orifício utilizando fio de Kirschner. O grupo III comparou a técnica 1 com a técnica 4, no qual foi estudado a influência da utilização da sonda no preparo do orifício. O resultados da comparação da técnica. de perfuração do orifício de acordo com os parâmetros estudados (carga máxima de arrancamento, rigidez, carga no limite de proporcionalidade, deslocamento máximo e deslocamento no limite de proporcionalidade), mostraram que não houve diferença estatisticamente significante entre as diferentes técnicas utilizadas para o preparo dos orifícios do pedículo vertebral na resistência ao arrancamento dos implantes. / An experimental study was conducted on swme vertebrae to investigate the effect of the technique of vertebral pedicle perforation on the pullout resistance of the implants. The technique of perforation with a burr followed by tapping of the pedicular canal (technique 1) was individually compared to the remaining ones, i.e., perforation with a burr without tapping of the pedicular canal (technique 2), perforation with a Kirschner wire with tapping of the pedicular canal (technique 3), and perforation with a probe without tapping of the pedicular canal (technique 4). Three experimental groups were used according to orifice preparation. Group I was used to compare technique 1 to technique 2, with a study of the effect of tapping on the pedicular canal. Group II was used to compare technique 1 with technique 3, with a study of the effect of mode of orifice preparation using a Kirschner wire. Group III was used to compare technique 1 to technique 4, with a study of the effect of the use of a probe for orifice preparation. Comparison of the techniques of orifice preparation according to the parameters studied (maximum pullout load, stiffness, load in the proportionality limit, maximum dislocation, and dislocation in the proportionality limit) showed no statistically significant difference between the various techniques used for preparation of the orifices of the vertebral pedicle, in terms of their effect on the pullout resistance of the implants.

Com o objetivo de se estudar a estabilidade da resistência mecânica da fixação pedicular do segmento vertebral, foram realizados ensaios mecânicos de sistemas de fixação pedicular compostos por parafusos hastes, sapatas e porcas, fabricados em titânio. Os ensaios foram flexo-compressão e flexão lateral, realizados na máquina universal de ensaio com a finalidade de se avaliar a influência da estrutura dos parafusos pediculares canulados (ocos) e não canulados (maciços) e a utilização ou não das sapatas na estabilidade de fixação do sistema. Os ensaios foram realizados na fase elástica, durante todo o tempo de aplicação das cargas. Foram realizadas três combinações de cada ensaio, com troca dos parafusos e sapatas do seguinte modo: parafusos canulados com sapata (CCS), canulados sem sapata (CSS) e não canulados sem sapata (NCSS). Os corpos de prova foram confeccionados em madeira mogno, e foram ensaiadas dez montagens de cada combinação, para os dois tipos de ensaios. Os resultados dos ensaios permitiram o cálculo do momento fletor para os valores das deflexões máximas em cada ensaio, assim como a rigidez e a energia absorvida. No ensaio de flexo-compressão, a análise de variância do momento fletor entre os grupos mostrou que não houve diferença significativa (CCS x CSS (p=0,304; CCS x NCSS (p=0,447); CSS x NCSS (p=0,183). O mesmo resultado foi encontrado para a rigidez (CCS x CSS (p=0,988); CCS x NCSS (p=0,500); CSS x NCSS (p=0,272), e para a energia absorvida (CCS x CSS (p=0,751); CCS x NCSS (p=0,673); CSS x NCSS (p=0,738). No ensaio de flexão lateral, a análise de variância do momento fletor entre os grupos mostrou que não houve diferença significativa (CCS x CSS (p=0.304); CCS x NCS (p=0,883); CSS x NCSS (p=0,186). O mesmo resultado foi encontrado para a rigidez (CCS x CSS (p=0,285); CCS x NCSS (p=0,957); CSS x NCSS (p=0,147), e para a energia absorvida (CCS x CSS (p=0,304); CCS x NCSS (p=0.892): CSS x NCSS (p=0,182). / Mechanical tests of the pedicle fixation systems composed of screws, rods, devices and nuts, made of titanium were realised with the purpose of studying the stability of mechanical resistance of the pedicle fixation of vertebral segments. The tests were bending-compression and lateral flexion done in the universal machine of test aiming at analysing the influence oft he structure of the hollowed pedicles screws and massy pedicles screws and the use or not of the devices in the stability of system fixation. The tests were carried out during the elastic phase, while the loads were being applied. Three combinations of each test were carried out, exchanging the devices and screws in the following way: screws with a device (CCS), screws without a device (CSS) and massy screws without devices (NCSS). The implants were made of \"mogno\" and ten (10) specimens used for each combination for both kinds of tests. The results of the tests allowed the calculation of the bending moment for the value in the maximum deflection of each test as well as the stiffness and energy absorbed. In test of bending compression, the analysis of variation of the bending moment among the groups showed that there was no difference (CCS x CSS (p=0,304); CCS x NCSS (p=0,447); CSS x NCSS (p=0,183)). The same result was found for the stiffness (CCS x CSS (p=0,988); CCS x NCSS (p=0,500); CSS x NCSS (p=0,272)), and the absorbed energy (CCS x CSS (p=0,751); CCS x NCSS (p=0,673); CSS x NCSS (p=0,738)). In the flexion lateral, the analysis of the variation of the bending moment the groups showed no difference (CCS x CSS (p=0,304); CCS x NCSS (p=0,883); CSS x NCSS (p=0,186)). The same result was found for the stiffness (CCS x CSS (p=0,285); CCS x NCSS (p=0,957); CSS x NCSS (p=0,147), and the absorbed energy (CCS x CSS (p=0,304); CCS x NCSS (p=0,892); CSS x NCSS (p=0,182)).

<p>Loosening of implants is a frequent complication in orthopaedic surgery. The aim of this thesis was to evaluate hydroxyapatite coating of pedicle screws with mechanical and histological methods and to correlate the results with the radiological findings.</p><p>Hydroxyapatite (HA) coating of pedicle screws was investigated in experimental studies in sheep. Nine sheep were operated on with destabilising laminectomies at L2-L3 and L4-L5 and stabilised with pedicle screw instrumentations, where HA coated and uncoated screws were used in a randomised fashion. After both 6 and 12 weeks of implantation, the HA coated screws demonstrated a higher bone-to-implant contact and a higher amount of bone in the area close to the screw. The pull-out resistance, stiffness and total energy to failure was higher for the HA coated screws after 12 weeks of implantation.</p><p>HA coating of pedicle screws was examined in two clinical studies. In the first series, the patients were stabilised with pedicle screw instrumentations, where HA coated screws were used in either the upper or lower instrumented level in a randomised fashion. After 10-22 months of implantation, the extraction torque was markedly higher for the HA coated screws. In the second series, instrumentations with uncoated, partly HA coated or fully HA coated screws were used. After 11-16 months implantation, the extraction torques were recorded. There were significant differences between all three groups, with the lowest extraction torques for the uncoated screws and the highest torques for the fully HA coated screws. The frequency of radiolucent zones surrounding the screws was higher for the uncoated screws than for the HA coated screws.</p><p>Radiographs from both experimental and clinical studies were examined. Screws demonstrating radiolucent zones were compared to screws without zones with respect to pull-out resistance, extraction torque, bone-to-implant contact and amount of bone surrounding the screws. All these variables demonstrated higher values for the screws without radiolucent zones. The frequency of radiolucent zones surrounding uncoated screws in the clinical study was 53%.</p><p>Conclusions: Radiolucent zones are good predictors of screw loosening. The frequency of radiolucent zones is higher than previously described. Hydroxyapatite coating improves the purchase of pedicle screws and reduces the frequency of screw loosening.</p>