The incidence of surgical site infection (SSI) in pediatric spinal deformity has been reported to remain high in the United States in spite of efforts made to reduce SSI. The risk of SSI is associated with multiple factors. For example, the heterogeneity of patients with different clinical and surgical characteristics in this population imposes challenges to identify the most beneficial preventive strategies for individual patients. This dissertation sought to advance understanding of risk factors and preventive strategies for SSI in individual pediatric patients undergoing spinal deformity surgery. Although the literature reports various risk factors and preventive strategies associated with SSI, there are no reliable review papers using formal methodology to aggregate evidence. The first aim of the dissertation was to conduct a systematic review and a meta-analysis to assess published literature investigating associations between various risk factors and SSI in pediatric patients undergoing spine surgery. The systematic review and the meta-analysis were conducted among peer-reviewed journals published in English between January 2000 - April 2019 using the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA-P). Studies included pediatric patients with spinal deformity undergoing surgical procedures in North America and were assessed for risk factors of SSI. Of 763 articles identified, thirteen met inclusion criteria after abstract or full manuscript review, and seven studies were rated as average and six as poor based on the quality checklist. The meta-analysis identified obesity/overweight, neuromuscular etiology, gastrostomy tube, non-ambulatory status, pelvic instrumentation, and high estimated blood as significant risk factors for SSI. Because the published literature does not identify which individual patients are at high risk for SSI, the second aim of this dissertation was to create a calculator using prediction modeling including patient, surgical and hospital characteristics to quantify the risk of SSI in individual patients. A retrospective cohort study was conducted using a database from seven centers that included 3,092 pediatric patients (0-21 years of age) with spinal deformity who underwent primary, revision, or definitive spinal fusion from 2004 to 2018. A total of 132 SSI (4.5%) within 90 days after surgery were identified. Candidate risk factors in this study included 31 patient, 12 surgical and 4 hospital factors that were present or determined before the surgery and unlikely to be modifiable. The final prediction model achieved adequate predictive ability (area under the curve [AUC]: 0.76) and included 10 risk factors: overweight/obese, neuromuscular etiology, American Society of Anesthesiologist Physical Status Classification System (ASA) >1, non-ambulatory status, abnormal hemoglobin (HGB) level, high white blood cell (WBC) count, revision surgery, presence of pelvic instrumentation, procedure time for ≥7 hours, and <100 spine surgical case per year per institution. Based on these findings, a risk probability calculator to predict the risk of SSI in individual patients was developed. There are a number of preventive strategies that have been recommended in consensus-based guidelines in the United States. The third aim of this dissertation was to investigate the association between preventive care measures and SSI and predict the reduction of SSI probability in individual patients by these preventive strategies. The database used in Aim 2 was also utilized to investigate the association between preventive care measures and the risk of SSI. Examined preventive strategies were the use of topical vancomycin, povidone-iodine irrigations, multilayered closure, impermeable dressing, the enrollment in Children’s Hospitals’ Solutions for Patient Safety (SPS) program or in the Comprehensive Unit-based Safety Program (CUSP), and adherence to the institutional perioperative antibiotic prophylaxis guideline. None of these preventive strategies were included in the risk model from Aim 2. When the CUSP/SPS enrollment alone was in the model, patients whose procedures were performed when sites were enrolled in the programs had 49.4% decrease in SSI (odds ratio [OR]:0.51, [95% CI: 0.32; 0.81], p=0.005) and AUC of 0.56. When CUSP/SPS enrollment was added to the risk model from Aim 2, the model revealed that patients whose procedures were performed when sites were enrolled in the CUSP/SPS had an average 48.9% decrease in SSI (odds ratio: 0.51, [95% CI: 0.29; 0.82]). The final prediction model demonstrated adequate predictive ability (AUC: 0.77). This dissertation highlighted factors associated with an increased risk of SSI and preventive strategies related to a reduced risk of SSI in pediatric patients undergoing spinal deformity surgery. The results of this study will enable healthcare providers to calculate the risk of SSI and effects of preventive strategies in reducing the risk of SSI in individual patients. In the long term, the information from this study could be used to enhance personalized care in clinical practice to prevent SSI in individual patients as well as to facilitate patient education and shared decision-making.

In today's health care environment tremendous efforts are being made by Health Maintenance Organizations (HMOs) to deliver appropriate patient care while controlling utilization of services and costs. One area of concern over the past two years has been the apparent over-utilization of spinal surgeries within a local Senior HMO. This HMO has no specific plan or physician guidelines for the management of low back pain. Utilization of spinal surgeries is measured in incidence of admissions per thousand members of the Senior HMO. Over the past two years the incidence of spinal surgeries per thousand has grown from 2.4 in 1995, 4.1 in 1996 and 7.4 during the first quarter of 1997. This is compared to a suggested rate of 1.5 per thousand for similar HMO populations around the country. The purpose of this study was to determine the effectiveness of the presentation of a treatment algorithm and physician guidelines for the management of low back pain (LBP). In order to determine the effectiveness of the presentation of the algorithm, the incidence of spinal surgeries per thousand for nine quarters prior to the presentation was compared to the incidence per thousand for the three quarters following the presentation. Results of this comparison showed a slight drop, but statistically insignificant (P = .62), in the rate of surgeries compared to the previous year. When compared to the previous two years the rate was actually slightly higher, but statistically insignificant (P = .57) after the presentation. Although the comparisons were determined to be insignificant, trend analysis indicated a gradual rise in the incidence during the initial five quarters, a plateau during the next four quarters, and a slight decrease in the rate of surgeries during the last three quarters which followed the introduction of the treatment algorithm. At this time it would be appropriate to continue the analysis of quarterly data and continue feedback and education to the primary care physicians in an attempt to promote proper utilization of spinal surgeries and overall management of LBP.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this experiment was to document the postoperative evolution of New Zealand rabbits that underwent a hemi laminectomy surgery (T13-L1) and received a graft of autogenous muscle as an hemostatic agent into the spinal canal. These animals were followed for a period of 14 and 28 days with daily neurological assessments and, at the end of their follow-up period, were euthanized in order to remove the graft site to be examined microscopically. The animals were divided into 6 groups such as the control group A and B, C and D treated with 25% decrease of the medullary canal and, E and F treated with 50% decrease of the medullary canal. All groups were evaluated neurologically every day until euthanasia. Groups A, C and E were euthanized at 14 days after the surgery and groups B, D and F at 28 days. The segments T11-L3 vertebral column of all the rabbits were collected and sent for histopathological examination. In order to evaluate the neurological postoperative effect, the animals were classified daily by the Tarlov scale and the results were compared by nonparametric Kruskal-Wallis test for each time (days). There was no statistical difference among the groups. Histopathological examination showed the presence of muscle grafted in the spinal canal and the spinal cord compression caused by the graft. / A hemorragia é uma preocupação importante em pacientes submetidos a intervenção cirúrgica descompressiva da medula espinhal ou de estabilização na coluna vertebral. O objetivo desse experimento foi documentar a evolução pós-operatória de coelhos Nova Zelândia que sofreram hemilaminectomia (T13-L1) e receberam um segmento de músculo autógeno como agente hemostático dentro do canal vertebral. Os animais foram separados em seis grupos sendo os grupos A e B controle, C e D tratados com diminuição de 25% do canal medular e E e F tratados com diminuição de 50% do canal medular. Todos os coelhos tiveram avaliação neurológica diária até a eutanásia. Aqueles dos grupos A, C e E sofreram eutanásia aos 14 dias de pós-operatório e os demais (B, D e E) aos 28 dias. Os segmentos T11-L3 da coluna vertebral contendo a medula espinhal de todos os coelhos foram coletados e enviados para exame histopatológico. Para avaliação neurológica no pós-operatório, os animais foram classificados diariamente pela escala de Tarlov e os resultados foram comparados entre eles pelo teste não paramétrico de Kruskal-Wallis para cada tempo (dia). Não houve diferença estatística da avaliação neurológica entre os grupos estudados. O exame histopatológico demonstrou a presença do músculo transplantado no canal vertebral e a compressão da medula espinhal provocada pelo enxerto.

Com o objetivo de avaliar os efeitos do tempo da descompressão medular em 50 ratos, machos, da raça Wistar, criou-se um modelo experimental de compressão medular através da passagem de uma fita de tecido (cetim), que reduz em 30% o diâmetro do canal vertebral na região da coluna torácica após laminectomia (TIX E TX). Os animais foram distribuídos em cinco grupos com 10 ratos cada, sendo: grupo A, controle da técnica de exposição medular atraumática, sem lesão; grupo B, submetidos à compressão medular, seguida de descompressão cinco minutos após a lesão; nos grupos C e D, realizou-se o mesmo procedimento do grupo B, porém a descompressão ocorreu 24 e 72 horas após a compressão, respectivamente; os ratos do grupo E sofreram compressão, sem descompressão até o fim do experimento na quarta semana, quando os 50 ratos foram submetidos à eutanásia. Todos os animais com compressão (B, C, D e E) apresentaram paraplegia no pós-operatório imediato. A recuperação neurológica foi avaliada através do potencial evocado motor, da escala BBB de capacidade locomotora e do exame anatomopatológico do sítio da lesão. Observou-se relação direta entre o potencial de recuperação neurológica e o tempo da descompressão medular nos três métodos de avaliação / With the objective of evaluating the effects of medullary decompression time in 50 male Wistar rats, an experimental model of medullary compression was created, through the insertion of a satin tape, which reduces in 30% the diameter of the vertebral canal at the region of the thoracic column after laminectomy (TIX and TX). The animals were distributed in five groups with 10 rats each, as follows: group A: control of the technique of atraumatic medullary exposure, with no lesion; group B, submitted to medullary compression, followed by decompression five minutes after the lesion; groups C and D underwent the same procedure, but decompression was performed 24 and 72 hours after compression, respectively; and finally, rats from group E underwent compression without decompression up to the end of the experiment on the 4th week, when all 50 rats were euthanized. All animals submitted to compression (groups B, C, D and E) presented paraplegia in the immediate post-operative period. The neurological recovery was evaluated through the motor-evoked potential of the BBB scale of locomotor capacity and anatomopathological examination of the lesion site. A direct correlation between the neurological recovery potential and time of medullary decompression was observed at the three evaluation methods

Com o objetivo de avaliar os efeitos do tempo da descompressão medular em 50 ratos, machos, da raça Wistar, criou-se um modelo experimental de compressão medular através da passagem de uma fita de tecido (cetim), que reduz em 30% o diâmetro do canal vertebral na região da coluna torácica após laminectomia (TIX E TX). Os animais foram distribuídos em cinco grupos com 10 ratos cada, sendo: grupo A, controle da técnica de exposição medular atraumática, sem lesão; grupo B, submetidos à compressão medular, seguida de descompressão cinco minutos após a lesão; nos grupos C e D, realizou-se o mesmo procedimento do grupo B, porém a descompressão ocorreu 24 e 72 horas após a compressão, respectivamente; os ratos do grupo E sofreram compressão, sem descompressão até o fim do experimento na quarta semana, quando os 50 ratos foram submetidos à eutanásia. Todos os animais com compressão (B, C, D e E) apresentaram paraplegia no pós-operatório imediato. A recuperação neurológica foi avaliada através do potencial evocado motor, da escala BBB de capacidade locomotora e do exame anatomopatológico do sítio da lesão. Observou-se relação direta entre o potencial de recuperação neurológica e o tempo da descompressão medular nos três métodos de avaliação / With the objective of evaluating the effects of medullary decompression time in 50 male Wistar rats, an experimental model of medullary compression was created, through the insertion of a satin tape, which reduces in 30% the diameter of the vertebral canal at the region of the thoracic column after laminectomy (TIX and TX). The animals were distributed in five groups with 10 rats each, as follows: group A: control of the technique of atraumatic medullary exposure, with no lesion; group B, submitted to medullary compression, followed by decompression five minutes after the lesion; groups C and D underwent the same procedure, but decompression was performed 24 and 72 hours after compression, respectively; and finally, rats from group E underwent compression without decompression up to the end of the experiment on the 4th week, when all 50 rats were euthanized. All animals submitted to compression (groups B, C, D and E) presented paraplegia in the immediate post-operative period. The neurological recovery was evaluated through the motor-evoked potential of the BBB scale of locomotor capacity and anatomopathological examination of the lesion site. A direct correlation between the neurological recovery potential and time of medullary decompression was observed at the three evaluation methods