A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Adolescent Idiopathic Scoliosis (AIS) is typically treated surgically by Posterior Spinal Fusion (PSF) surgery. Intravenous analgesics and oral opioids are commonly used for pain management. Several adjunct therapies are used in addition to the standard treatments. One of these therapies is the use of dexmedetomidine (dex). Though dex has been found to be an effective sedative for post‐operative patients, there are also several adverse effects that are associated with its use. The purpose of this study was to investigate the effectiveness and overall benefit of using dex for pain control for patients undergoing PSF for AIS. IRB approval was obtained. A group of 43 patients with AIS undergoing PSF and using Dex for adjunctive pain control were matched with 43 patients who did not use Dex. The groups were matched based on gender, age, height, weight, and level of spinal fusion. During the patients’ post‐operative hospital stay, the total opioid use and clinical pain scores were compared between the two groups using t‐tests, with significance set at p<0.05. Total opiate use was 239.6 morphine equivalent doses in the non‐Dex (control) group and 246.2 in the group that received Dex (p=0.72). The average pain score in the control group was 2.3, and the group that received Dex was 2.6 (p =0.43). There were no differences in the complication rate between the two groups, specifically the oversedation rates and pulmonary complications. Lastly, the average length of stay for the control group was 4.8 days compared to the dex group, which was 5.0 days (p=0.35). Although adjunctive pain modalities may be very useful in the treatment of postoperative pain after PSF in patients with AIS, the use of Dex in this cohort did not improve pain scores, lower opioid use, or lower the LOS. Based on these results, we do not recommend the routine use of dexmedetomidine as an adjunctive pain control modality. Adjunctive modalities are important in pain control in patients with AIS undergoing PSF, but the use of dexmedotomidine was not effective in improving pain control.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Surgical correction of Adolescent Idiopathic Scoliosis (AIS) carries a substantial risk of complication. The literature supports improved perioperative outcomes through the two surgeon strategy in other complex orthopedic procedures. Does the presence of 2 versus 1 attending surgeons affect the perioperative morbidity of posterior spinal fusion (PSF) in patients with AIS curves greater than 70°? We reviewed the database from a large regional children’s hospital of all patients with AIS curves greater than 70° who underwent PSF from 2009‐2014 and divided the cohort into single versus 2‐surgeon groups (28 vs. 19 cases, respectively). We analyzed cases for length of surgery, estimated blood loss, and length of stay. The groups were identical when comparing age, gender, spinal levels fused, and average ASA score. However, the average Cobb angle in the single surgeon group was significantly less than in the 2 surgeon group at 78.4 vs 84.0 degrees, respectively (p=0.049). Mean operative time for single versus 2 surgeons was 238 (SD 48) vs 212 (SD 46) minutes (p=0.078). Mean percent estimated blood loss was 26% (SD 14.1) for single surgeon vs 31% (SD 14.9) for 2 surgeons (p=0.236), and mean estimated blood loss for single surgeon vs 2 surgeons was 830ml (SD 361) vs 1045ml (SD 346) (p=0.052). Mean length of stay was significantly decreased in the 2 surgeon group at 5.16 days (SD 1.7) versus the single surgeon group at 6.82 days (SD 6.82) (p=0.002). The use of 2 surgeons in AIS deformity correction at an experienced regional children’s hospital did not improve clinical outcomes. The average length of stay was reduced in the two‐surgeon group, but there was no significant impact on blood loss or operative time. However, this study does not rule out the potential for positive impact with a two‐surgeon strategy, and given previous supportive data in the literature, this approach should further evaluated to determine its effect on improving perioperative outcomes.

by Henry Yurianto. / "18 September 1998." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 138-149). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

Pedicle screw breakage and loosening remain as clinical complications of short segment instrumentation procedures for spinal stabilization. This study has directly visualized and measured elastic, plastic and total vertebral pedicle trabecular bone full-field strains in the regions immediately surrounding the pedicle screw during pedicle screw insertion by utilizing functional microCT imaging and digital volume correlation. Human, porcine and polyurethane foam samples were analyzed and compared. Analysis showed that when osteoporotic human, normal human and porcine pedicle trabecular bone samples were compared, osteoporotic samples showed higher peak plastic strains and greater variability of these strains from their means. This suggests that osteoporotic human samples are non-uniformly elastic and plastic, while normal human and porcine samples are more uniformly elastic and plastic throughout the trabecular structure. PU-foams are not appropriate as models for pedicle trabecular bone in the in vivo environment since strain results showed dissimilar plastic and elastic strain magnitudes than human and porcine pedicle trabecular bone. This study may aid in the development of performance criteria for new PU-foams and improved pedicle screw designs. / Graduation date: 2004

Spinal fusion is the process by which two or more vertebral levels are joined into a single, solid bone mass in order to restore stability to a spine that has been compromised by trauma, degeneracy or metastasis. Fusion is accomplished through internal hardware positioned anteriorly, posteriorly, or with combined anterior-posterior instrumentation. Since the 1990s the frequency of spinal fusions has been rising, and this trend is expected to continue. Posterior approaches to fusion are most common, primarily consisting of pedicle screw and rod constructs. Despite the high success rate for bony fusion with pedicle screw fixation, this technique poses risks to delicate neurological and vascular structures and is heavily dependent on surgeon expertise. In this thesis, a novel and less invasive posterior spinal hardware system was designed and evaluated, which solely utilizes the spinous processes and laminae of the vertebrae as the point of the bone-implant interface. Morphological and biomechanical studies of the posterior spine were undertaken in order to define important geometric information to guide the design of the proposed hardware and to determine the strength of the posterior elements throughout the spine to assess their ability to support posterior element plating. Utilizing this information, a modular dual plate fusion system was developed for single or multi-level fusion. The system accounts for the native curvature of the spine and can be extended to additional vertebral levels at the time of insertion, or at any later time. Prototypes were manufactured in titanium. Positive biomechanical results were found when the proposed hardware was used as a supplement to anterior instrumentation. Additionally, work focused on 2D-3D registration of neutral CT data with flexion extension x-ray images, was undertaken and shown to yield improved accuracy of important vertebral metrics utilized for clinical assessment of spine stability. This technique is applicable to the evaluation of pathology and kinematics at any level of the spine, including post-fusion adjacent level degeneration. The culmination of this work has resulted in a novel, patent pending posterior element spinal fusion system.

Spinal fusion is the process by which two or more vertebral levels are joined into a single, solid bone mass in order to restore stability to a spine that has been compromised by trauma, degeneracy or metastasis. Fusion is accomplished through internal hardware positioned anteriorly, posteriorly, or with combined anterior-posterior instrumentation. Since the 1990s the frequency of spinal fusions has been rising, and this trend is expected to continue. Posterior approaches to fusion are most common, primarily consisting of pedicle screw and rod constructs. Despite the high success rate for bony fusion with pedicle screw fixation, this technique poses risks to delicate neurological and vascular structures and is heavily dependent on surgeon expertise. In this thesis, a novel and less invasive posterior spinal hardware system was designed and evaluated, which solely utilizes the spinous processes and laminae of the vertebrae as the point of the bone-implant interface. Morphological and biomechanical studies of the posterior spine were undertaken in order to define important geometric information to guide the design of the proposed hardware and to determine the strength of the posterior elements throughout the spine to assess their ability to support posterior element plating. Utilizing this information, a modular dual plate fusion system was developed for single or multi-level fusion. The system accounts for the native curvature of the spine and can be extended to additional vertebral levels at the time of insertion, or at any later time. Prototypes were manufactured in titanium. Positive biomechanical results were found when the proposed hardware was used as a supplement to anterior instrumentation. Additionally, work focused on 2D-3D registration of neutral CT data with flexion extension x-ray images, was undertaken and shown to yield improved accuracy of important vertebral metrics utilized for clinical assessment of spine stability. This technique is applicable to the evaluation of pathology and kinematics at any level of the spine, including post-fusion adjacent level degeneration. The culmination of this work has resulted in a novel, patent pending posterior element spinal fusion system.

The goal of this thesis was to assess the validity of a computer simulated Radiostereometric Analysis (RSA) environment and assess the use of novel migration origin styles for use in the assessment of spinal fusion success in post-surgical adolescent idiopathic scoliosis patients. A parallel precision study was conducted with a physical phantom and identical computed simulated spinal fusion model. This study was used to conduct a precision validation of the simulate RSA environment. The origin style assessment was done in comparison with the translational and rotational Limits of Clinical Significance defined by Pape et al (2002) and Johnsson et al (2002) respectively [1], [2]. This thesis concluded that the use of a simulated environment is an acceptable method for the creation of phantom RSA research studies. It was also shown that both the Apex and Dual Origin Styles equally accurate and precise.

Thesis (M. Med. Sc.)--University of Hong Kong, 2003. / Includes bibliographical references (leaves 81-94). Also available in print.

Made available in DSpace on 2015-07-22T20:50:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-25 / As BMPs, proteínas indutoras de crescimento ósseo, desde o início de sua utilização têm sido avaliadas em diferentes modelos experimentais objetivando determinar sua eficácia. Sabemos que algumas substâncias podem interferir positiva ou negativamente quando utilizadas de forma sistêmica ou local,associadas à BMP.Objetivo:Este estudo tempo objetivo avaliar as possíveis interferências da utilização de antibioticoterapia profilática pré e pós-operatória,utilizando-se como princípio ativo a cefazolina,aplicada a um modelo experimental em coelhos.Métodos:Foram utilizados dois grupos de coelhos fêmea, neozelandeses,submetidos à artrodese intertransversa da coluna lombar,segmento L5-L6,por via posterior.No primeiro grupo foi utilizado o enxerto autólogo associado ao biocomposto BMP bovino, 1,0mg e hidroxiapatita,9,0mg).No segundo grupo foi realizado o mesmo procedimento e utilizado o mesmo biocomposto porém os animais foram submetidos a antibioticoterapia profilática com cefazolina iniciada duas horas antes e mantida por 24 horas após o término do procedimento.Os animais foram acompanhados por 15 semanas,isolados em cativeiro e avaliados diariamente por veterinário sob o ponto de vista clínico e neurológico,sendo posteriormente sacrificados e retiradas as peças cirúrgicas para serem submetidas à análise radiográfica e histológica.Resultados:Para o grupo 1,a quantidade e localização do material implantado variaram entre os indivíduos, porém,na maioria dos casos(6 amostras),a quantidade de partículas de osso homólogo era insignificante e estava dispersa ao longo do tecido mole que recobre o dorso da vértebra,circundado por tecido reacional com área de necrose.Nos demais casos as partículas com reabsorção preenchiam o reduzido espaço entre os processos transversos.Para o grupo 2,a quantidade do material e sua localização também variaram entre os indivíduos.Na maioria dos casos inúmeras partículas de osso mole preenchiam o espaço entre os processos laterais cuja neoformação óssea levou ao aprisionamento de algumas dessas partículas.Todos os casos exibiram formação em maior ou menor intensidade de tecido cartilaginoso na superfície dos processos transversos.A análise radiográfica mostrou em sua frequência relativa maior frequência de fusão completa para o grupo 2 quando comparado ao grupo 1. Conclusão:Do ponto de vista histológico para o modelo e período experimental analisado,inferimos que,embora nenhum dos tratamentos propostos tenha promovido o completo fusionamento das vértebras por tecido ósseo,a utilização de osso homólogo + BMP bovina, associada à aplicação de cefazolina,promoveu maior formação cartilaginosa e óssea com menor índice de rejeição do material enxertado na área doadora, quando comparada ao grupo sem associação de cefazolina.Do ponto de vista radiográfico,a análise relativa também demonstrou-se superior para o grupo onde foi utilizado cefazolina... / TEDE / BV UNIFESP: Teses e dissertações

Chronic pain is an ever-present issue and some estimate its cost to society at $635 billion per year. Not only does chronic pain cause increased visits to medical personnel, it also complicates other medical conditions and lowers productivity in the workplace. One area of study includes Chronic Post Surgical Pain (CPSP) in children that have undergone spinal fusion surgery for Adolescent Idiopathic Scoliosis (AIS). Some of the major factors that may lead to CPSP include preoperative pain, psychosocial factors, age, intraoperative nerve injury, acute postoperative pain, and genetics. In order to explore the psychological factors, our lab has employed an Unpredictable Chronic Mild Stress (UCMS) paradigm, which models unforeseen life stressors and depression. Some sensory testing was conducted included Hot Plate and von Frey fiber testing. Previous studies from this lab have shown that adult male mice have hyperalgesia to thermal stimuli following a UCMS paradigm. To further explore this finding, a younger mice cohort of both sexes and a cohort that underwent Maternal Deprivation (MD) were added. Maternal Deprivation is a model of early-childhood stress and older female mice have been shown to have changes in thermal sensitivities as a result of early childhood stressors. Our lab found that stressed young females also exhibit a heightened sensitivity to thermal stimuli at 49°C compared to their male and control counter parts. These results indicate that the thermal sensitivity of young females can be affected by early childhood stress and depression.