A cirurgia da coluna vertebral tem se desenvolvido muito nos últimos anos em decorrência da evolução dos sistemas de fixação. O comportamento da interface do parafuso com o osso continua sendo um aspecto não muito dominado. Como o parafuso é a âncora de sustentação, o trabalho procura investigar as técnicas de introdução do parafuso pedicular. Para atingir esse objetivo desenvolvemos o trabalho por meio de estudo com ensaios mecânicos de arrancamento e estudo histológico. Dois tipos de parafusos pediculares foram utilizados: parafuso pedicular do sistema USIS (Ulrich) e parafuso pedicular do sistema USS (Synthes). Os ensaios de arrancamento foram realizados em corpos de prova de madeira e poliuretano. O estudo histológico foi realizado em vértebras lombares de cadáver humano. No estudo envolvendo o parafuso USIS, foram testados os seguintes parâmetros: orifícios feitos com sonda e orifícios feitos com broca, todos do mesmo diâmetro do diâmetro interno do parafuso. Também foi testado o efeito do macheamento em relação ao não macheamento, nos orifícios feitos com broca. No estudo com os parafusos USS foram testados o efeito do diâmetro do orifício piloto tanto no estudo histológico como no arrancamento. No arrancamento destes parafusos também foi testado o efeito do tipo de orifício feito com sonda e com broca. O trabalho foi dividido em etapas: Primeira etapa foi o estudo de arrancamento do parafuso USIS; segunda etapa, estudo histológico de vértebra instrumentada com parafuso USIS, esta parte do trabalho foi constituída por análise de microscopia de luz e microscopia eletrônica de varredura; terceira etapa foi o arrancamento do parafuso USS; e quarta etapa foi o estudo histológico de vértebra instrumentada com parafuso USS. Os resultados da primeira etapa demonstraram que sonda teve efeito melhor do que broca, porque o resultado dos ensaios de arrancamento nos orifícios feitos com sondas teve maior força de arrancamento do que nos orifícios feitos por brocas. Na segunda etapa, análise histológica, verificou-se que os orifícios feitos por sonda apresentaram-se menores e com menor índice de fragmentação ao redor dos orifícios. Esses feitos tiveram diferença estatística significante, tanto na primeira, quanto na segunda etapa. Com relação ao macheamento não foi constatada diferença entre o não macheamento, em nenhuma das duas etapas. Na terceira etapa foi observado que, quando o orifício piloto ultrapassa o diâmetro interno do parafuso, ocorre tendência de queda na força de arrancamento de modo significativo, enquanto que orifício menor que o orifício piloto não tende a causar muita diferença na força de arrancamento em relação ao orifício correspondente ao diâmetro interno do parafuso. Também foi observado que o orifício feito com sonda oferece melhor força de ancoragem do que orifício feito com broca. Na quarta etapa foi constatado que quanto menor a broca para abrir o orifício piloto, menor o diâmetro do orifício, e não houve diferença significativa quanto ao índice de fragmentação ao redor do orifício entre os diferentes tamanhos de broca. Como conclusão pode-se dizer que sonda é melhor para se fazer o orifício piloto, uma vez que alarga menos o orifício, lesa menos as trabéculas ao redor do orifício e proporciona maior força de ancoragem do que broca. Também se pode concluir que o instrumental de menor diâmetro para abertura do orifício piloto é melhor, e o ponto crítico seria o diâmetro interno do parafuso. Não se deve fazer orifício piloto com instrumento de diâmetro maior que o diâmetro interno do parafuso. Não se constatou vantagem em relação ao fato de realizar ou deixar de realizar o macheamento. / Spine surgery has developed a lot in the last years because of the evolution of the fixation system. The behavior of a screw in the bone is still unknown in many ways. Because the screw is the anchor of sustentation, this work tries to find the answers involving the pedicle screw fixation. To reach this objective we developed this work based on mechanical and histological studies. Two kinds of pedicle screws were used: pedicle screw of the USIS (Ulrich) and pedicle screw of the USS system (Synthes). The pullout tests were made in wood and polyurethane. The histological study was done in lumbar vertebra of humans. In the study about the USIS screw, the follow parameters were tested: hole done with probe and hole done with drill, all of the same inner diameter of the screw. The effect of tapping and not tapping the hole done with drill was tested. In the USS screw study, the effect of the diameter pilot hole in the pullout tests and its historical analysis was seen. In the pullout tests of these screws, both kind of holes done with probes and a drill were tested. The work was divided into stages; first stage was the study of the pullout of the USIS screw; second stage was two studies, a light-microscopic one and a sweeping-electronic-microscope one of the slides of the instrumented vertebra with USIS screws; third stage was the study of the USS screws pullout comparing the relationship between the diameter of the holes and the inner diameter of the screw together with the type of hole (drill and probe); fourth stage was light-microscopic histological study of the instrumented vertebras which had had USIS screws. Results of the first stage showed that probes were more efficient than drills because the mechanical tests of pullouts from probe-made-holes showed the need of the use of a stronger force. In the second stage, a light-microscopic analysis showed that probe-made-holes had a lesser minimum diameter and a lower index of fragmentation than drill-made holes. With relation to the tapping, there was no difference between the holes. Under electronic microscope sweeping, it was seen that probes betters compact the bone around the screw. In the third stage, it was seen that when 9 the pilot orifice was greater than the screws internal diameter a significantly lower force was needed for pullout, while when the pilot orifice was smaller it did not significantly increase the force needed. It was also seen that probe-made-holes had a better anchorage than the drill-made-holes. In the fourth stage, the histological analysis of the slides done with light-microscopy showed that the smaller the diameter of the drill the smaller minimum diameter; there was no significant difference between fragmentation indexes. Conclusion: Probes are better than drills to make a pilot hole because they cause less damage to the surrounding bone and give a stronger anchorage for the screw; the smaller the instrument used to make the pilot hole, better will be the strength of the screws anchorage; the critical point which the hole must not exceed is the internal diameter of the screw. Tapping, or not, makes no difference to the anchorage.

INTRODUCTION: Computer aided navigation is an important tool which has the capability to enhance surgical accuracy, while reducing negative outcomes. However, it is a relatively new technology and has not yet been accepted as the standard of care in all settings. OBJECTIVES: The objective of the present study is to present the development and current state of technologies in computer aided navigation in Orthopedic Spine Surgery, specifically in navigated placement of pedicle screws, to examine the clinical need for navigation, it's effect on surgical accuracy and clinical outcome and to determine whether the benefits justify the costs, and make recommendations for future use and enhancements. CONCLUSION: Computer aided navigation in pedicle screw placement enhances accuracy, reduces the probability of negative outcomes, reduces the exposure of the patient and staff to radiation, reduces operative time, and provides cost-savings. Future investigations may potentially enhance this effect further with the use of innovative augmented reality type displays.

Low back syndrome affects 20% of people, and it is estimated that 30% of patients are unable to return to work after surgery. The monitoring of health care outcomes could improve the delivery of health services. The health performance conceptual framework, derived from the Donabedian model, was used to evaluate the functional outcome, clinical recovery, response to surgery, and physician performance of the surgical management of lumbar spine degeneration. A quantitative study (n=685) was undertaken using an administrative database in a repeated-measures design. The clinical and functional outcome improvements were analyzed using t tests. Surgical complexity on health outcome was examined with ANOVA. Predictors of patient satisfaction was explored using Pearson's correlation and regression analyses. The results demonstrated highly significant improvements in functional (mean change 30%; ODI=16.79 -± SD 19.92) and clinical recovery (mean change 50%; modified-JOA=6.983 -± SD 2.613) with surgery at 3 months; a >50% positive response to surgery; and a > 90% patient satisfaction, sustained over a 2 year period. Complexity of surgery did not impact health performance. Strong correlations between the health performance metrics were detected up to 6-months from surgery. Poor clinical recovery and persistent functional disability were predictive of patient dissatisfaction. The social change implications for health policy are that a constellation of health performance metrics could predict the potential for functional and clinical recovery based on presurgery disability while avoiding medical expenditures for procedures with no health benefit; aid in health quality monitoring, peer comparisons, revision of practice guidelines, and cost benefit analysis by payers.

Background: Unplanned readmission has gained increasing interest as a quality marker for inpatient care, as it is associated with patient mortality and higher economic costs. Spinal neurosurgery is characterized by a lack of epidemiologic readmission data. The aim of this study was to identify causes and predictors for unplanned readmissions related to index diagnoses and surgical procedures. Methods: In this study, from 2015 to 2017, spinal neurosurgical procedures were recorded for surgical and non-surgical treated patients. The main reasons for an unplanned readmission within 30 days following discharge were identified. Multivariate logarithmic regression revealed predictors of unplanned readmission. Results: A total of 1172 patient records were examined, of which 4.27% disclosed unplanned readmissions. Among the surgical patients, the readmission rate was 4.06%, mainly attributable to surgical site infections, while it was 5.06% for the non-surgical patients, attributable to uncontrolled pain. A night-time surgery presented as the independent predictive factor. Conclusion: In the heterogeneous group of spinal neurosurgical patients, stratification into diagnostic groups is necessary for statistical analysis. Degenerative lumbar spinal stenosis and spinal abscesses are mainly affected by unplanned readmission. The surgical procedure dorsal root ganglion stimulation is an independent predictor of unplanned re-hospitalizations, as is the timing of surgery.

A vertebroplastia percutânea (VP) consiste na injeção de polimetilmetacrilato (PMMA) no corpo vertebral para alívio da dor e estabilização vertebral, porém seu uso na região cervical é restrito. No intuito de avaliar a efetividade e a segurança da VP na região cervical (VPC), foram avaliados 75 pacientes que se submeteram à VPC (n=101) por doença maligna (n=69) ou hemangioma vertebral (n=6) no período de janeiro de 1994 a outubro de 2007. A VPC foi realizada por uma abordagem ântero-lateral guiada por fluoroscopia. A dor foi graduada por uma escala variando de 0 a 10. O seguimento clinico (período médio de 8,8 meses) foi obtido em 57 (76%) pacientes: 48 tiveram a VPC indicada para controle da dor e nove para estabilização vertebral. Os dados foram analisados de forma univariada e multivariada. A efetividade analgésica foi obtida em 37 (77,1%) dos 48 pacientes seguidos, tendo sido associada ao volume de cimento injetado (P=0,011) e ao preenchimento vertebral (P=0,007) na análise multivariada. A estabilidade vertebral foi observada em 55 (96,5%) dos 57 pacientes, não se correlacionando com as variáveis estudadas. A curva de ROC identificou o preenchimento vertebral como preditor da efetividade analgésica (P=0,008), sendo 50% o melhor ponto de corte para discriminar a maior probabilidade de efetividade analgésica (sensibilidade de 78,0% e especificidade de 62,5%). O extravasamento de cimento foi identificado em 83 (82,2%) das 101 vértebras tratadas não se correlacionando com as variáveis estudadas. As complicações clínicas foram detectadas em 13 (17,3 %) pacientes: complicações locais em 10 (13,3%) e sistêmicas em três (4%) pacientes. As complicações clínicas foram estatisticamente relacionadas à ruptura do muro posterior (P=0,026) e ao extravasamento de PMMA no plexo venoso transverso (P=0,023). A taxa de mortalidade e morbidade a longo termo foi de 1,3% (um paciente) e 1,3% (um paciente). Pode se inferir que a VPC é um procedimento efetivo e seguro, sem se negligenciar os riscos potenciais de complicações. O preenchimento vertebral e o volume de cimento foram associados à efetividade analgésica, mas não à estabilidade vertebral. O preenchimento vertebral teve o maior poder discriminatório da efetividade analgésica, tendo sido obtido com o ponto de corte de 50 % o melhor equilíbrio entre sensibilidade e especificidade para se determinar a efetividade analgésica / Percutaneous vertebroplasty (PV) consists of an injection of polymethylmethacrylate (PMMA) into the vertebral body for pain relief and spinal stabilization, however reports of PV in the cervical spine (CPV) are scarce in the literature. To evaluate the effectiveness and security of CPV, we evaluated 75 patients (mean age, 51.3 years) who underwent CPV (n=101) for malignancies (n=69) and vertebral hemangiomas (n=6) between January 1994 and October 2007. CPV was performed via an antero-lateral approach, using fluoroscopic guidance. Pain intensity was scored with a scale ranging from 0 to 10. Follow-up (mean time of 8.8 months) was avaible in 57 (76 %) patients: 48 of them had CPV indicated for pain control and nine for spinal stabilization. Data were analysed by means of univariate and multivariate analysis. Pain improvement was observed in 37 (77.1%) out of 48 followed patients and was correlated in multivariate analysis with cement volume (P=0.011) and with vertebral filling (P=0.007). Spinal stabilization was observed in 55 (96.5%) of 57 followed patients and was related with none of the evaluated variables. The ROC curve identified the vertebral filling as a good predictor of pain improvement (P=0.008). The best cut-off point to discriminate pain improvement was 50% of vertebral filling (78.0% sensitivity and 62.5% specificity). In 83 (82.2%) of the 101 treated vertebral levels, at least one type of PMMA leakage was found. None of the evaluated factors were related significantly to PMMA leakage. Clinical complications were detected in 13 (17.3%) patients: local complications in 10 (13.3%) patients and systemic clinical complications in three (4.0%) patients. Posterior wall disruption (P=0.026) and transverse venous PMMA leakage (P=0.023) were significantly associated with clinical complications. Long-term morbidity and mortality rate was 1.3% (one patient) and 1.3% (one patient). CPV is a safe and efficacious procedure, but the potential for local and systemic complications must be considered. Cement volume and vertebral filling were associated with pain improvement but not with spinal stability. Vertebral filling has a good performance to predict pain improvement and a cut-off of 50% of vertebral filing obtained the best compromise between sensitivity and specificity to discriminate pain improvement

Over the past several decades rates of spine surgeries in the U.S. have increased dramatically. Spinal fusion surgery rates, in particular, have grown exponentially despite being one of the most costly, invasive, and controversial methods for treating patients suffering from back conditions. Furthermore, lumbar fusion surgeries continue to be performed at increasing rates despite a lack of scientific evidence and consensus that they are cost-effective and produce better clinical outcomes than less radical treatment of lower back pain. As a result, large amounts of healthcare dollars continue to be invested in these costly procedures which are potentially dangerous and have questionable efficacy in terms of improving patient outcomes. Importantly, there is a lack of population studies in the literature on spinal fusion surgeries from a health services research perspective. Therefore, the present research is a population based study using an administrative database and includes patients of all ages and payer types. The data used in the present study come from the Florida Agency for Health Care Administration (AHCA) and include all hospitalizations in Florida in 2010. The objective of the study is to analyze the incidence of spinal fusion surgeries in Florida hospitals for patients of all ages and payer types by demographic variables to understand who gets these surgeries and for which conditions. The first null hypothesis is that there are no statistically significant predictors of the incidence of lumbar/lumbosacral, dorsal/dorsolumbar spinal fusion surgeries in Florida hospitals. Logistic regression was used to analyze the incidence of fusion surgeries. The binary dependent variable was coded as a "1" for all patients who were a case (i.e. they received one of the five procedure codes being studied in the present research) and a "0" for all patients who were controls (meaning they did not receive any of the five fusion procedure codes). Logistic regression was used to predict the probability of an observation being a "1" given the independent variables included in the model. Additionally, hospital charges were analyzed to understand the associated hospital charges with these surgeries. The second null hypothesis is that there are no statistically significant predictors of the charges of Lumbar/Lumbosacral, Dorsal/Dorsolumbar spinal fusion surgeries in Florida Hospitals. A mixed effects model was used to test this hypothesis and the fixed effects which were included in the model were gender, age, race, principal payer, and principal procedure. A mixed effects model was chosen due to the fact that cases who had surgeries performed at the same hospital are not independent and therefore the data were clustered on hospitals. A random intercept term was used to address this fact. SAS software was used to complete all of the analyses. In 2010, there were 16,236 Lumbar/Lumbosacral, Dorsal/Dorsolumbar fusion surgery cases in Florida hospitals that were included in the case population and 21,856 individuals included in the control population for a total of 38,092 included in the study population. An understanding of who is most likely to receive a fusion surgery, at what age, and for which diagnoses, as has been done here, is extremely important. This knowledge can help researchers, policy makers, and physicians alike. Comprehensive physician practice guidelines for performing fusion surgeries still do not exist in the year 2013; therefore, in order to have the greatest impact, the efforts for creating the guidelines should be focused on those individuals who are most likely to receive fusions as shown for the first time by the data analyzed here. Given the high incidence of these surgeries in Florida alone, the need for practice guidelines cannot be overstated. The total hospital charges in Florida hospitals for the 16,236 cases were $2,095,413,584. Despite having the same principal diagnoses and a similar number of additional diagnoses, patients who received a fusion surgery resulted in approximately three times the charges as those incurred by the controls. Overall, the high incidence and charges for fusion surgeries shown in this study emphasize the importance of having a better understanding of when these surgeries are justified and for which patients. Without comprehensive practice guidelines established through evidence-based research this is difficult, if not impossible, to accomplish. The diagnoses which are most prevalent and show the most inconsistencies between cases may be a good starting point for such guidelines.

A vertebroplastia percutânea (VP) consiste na injeção de polimetilmetacrilato (PMMA) no corpo vertebral para alívio da dor e estabilização vertebral, porém seu uso na região cervical é restrito. No intuito de avaliar a efetividade e a segurança da VP na região cervical (VPC), foram avaliados 75 pacientes que se submeteram à VPC (n=101) por doença maligna (n=69) ou hemangioma vertebral (n=6) no período de janeiro de 1994 a outubro de 2007. A VPC foi realizada por uma abordagem ântero-lateral guiada por fluoroscopia. A dor foi graduada por uma escala variando de 0 a 10. O seguimento clinico (período médio de 8,8 meses) foi obtido em 57 (76%) pacientes: 48 tiveram a VPC indicada para controle da dor e nove para estabilização vertebral. Os dados foram analisados de forma univariada e multivariada. A efetividade analgésica foi obtida em 37 (77,1%) dos 48 pacientes seguidos, tendo sido associada ao volume de cimento injetado (P=0,011) e ao preenchimento vertebral (P=0,007) na análise multivariada. A estabilidade vertebral foi observada em 55 (96,5%) dos 57 pacientes, não se correlacionando com as variáveis estudadas. A curva de ROC identificou o preenchimento vertebral como preditor da efetividade analgésica (P=0,008), sendo 50% o melhor ponto de corte para discriminar a maior probabilidade de efetividade analgésica (sensibilidade de 78,0% e especificidade de 62,5%). O extravasamento de cimento foi identificado em 83 (82,2%) das 101 vértebras tratadas não se correlacionando com as variáveis estudadas. As complicações clínicas foram detectadas em 13 (17,3 %) pacientes: complicações locais em 10 (13,3%) e sistêmicas em três (4%) pacientes. As complicações clínicas foram estatisticamente relacionadas à ruptura do muro posterior (P=0,026) e ao extravasamento de PMMA no plexo venoso transverso (P=0,023). A taxa de mortalidade e morbidade a longo termo foi de 1,3% (um paciente) e 1,3% (um paciente). Pode se inferir que a VPC é um procedimento efetivo e seguro, sem se negligenciar os riscos potenciais de complicações. O preenchimento vertebral e o volume de cimento foram associados à efetividade analgésica, mas não à estabilidade vertebral. O preenchimento vertebral teve o maior poder discriminatório da efetividade analgésica, tendo sido obtido com o ponto de corte de 50 % o melhor equilíbrio entre sensibilidade e especificidade para se determinar a efetividade analgésica / Percutaneous vertebroplasty (PV) consists of an injection of polymethylmethacrylate (PMMA) into the vertebral body for pain relief and spinal stabilization, however reports of PV in the cervical spine (CPV) are scarce in the literature. To evaluate the effectiveness and security of CPV, we evaluated 75 patients (mean age, 51.3 years) who underwent CPV (n=101) for malignancies (n=69) and vertebral hemangiomas (n=6) between January 1994 and October 2007. CPV was performed via an antero-lateral approach, using fluoroscopic guidance. Pain intensity was scored with a scale ranging from 0 to 10. Follow-up (mean time of 8.8 months) was avaible in 57 (76 %) patients: 48 of them had CPV indicated for pain control and nine for spinal stabilization. Data were analysed by means of univariate and multivariate analysis. Pain improvement was observed in 37 (77.1%) out of 48 followed patients and was correlated in multivariate analysis with cement volume (P=0.011) and with vertebral filling (P=0.007). Spinal stabilization was observed in 55 (96.5%) of 57 followed patients and was related with none of the evaluated variables. The ROC curve identified the vertebral filling as a good predictor of pain improvement (P=0.008). The best cut-off point to discriminate pain improvement was 50% of vertebral filling (78.0% sensitivity and 62.5% specificity). In 83 (82.2%) of the 101 treated vertebral levels, at least one type of PMMA leakage was found. None of the evaluated factors were related significantly to PMMA leakage. Clinical complications were detected in 13 (17.3%) patients: local complications in 10 (13.3%) patients and systemic clinical complications in three (4.0%) patients. Posterior wall disruption (P=0.026) and transverse venous PMMA leakage (P=0.023) were significantly associated with clinical complications. Long-term morbidity and mortality rate was 1.3% (one patient) and 1.3% (one patient). CPV is a safe and efficacious procedure, but the potential for local and systemic complications must be considered. Cement volume and vertebral filling were associated with pain improvement but not with spinal stability. Vertebral filling has a good performance to predict pain improvement and a cut-off of 50% of vertebral filing obtained the best compromise between sensitivity and specificity to discriminate pain improvement

Operationen mit großem Gewebetrauma können mit starken postoperativen Schmerzen und ausgeprägten perioperativen Homöostasestörungen einhergehen. Dabei werden sowohl hyperinflammatorische als auch immunparalytische Reaktionen beobachtet, die sich negativ auf den postoperativen Verlauf auswirken können. Um eine effektive und sichere Analgesie zu gewähren, werden alternativ zu der intravenösen Therapie mit Opioiden zunehmend epidurale Verfahren eingesetzt. In dieser prospektiven, randomisierten und doppelblinden Studie wurde die patientenkontrollierte epidurale Analgesie mit der patientenkontrollierten intra-venösen Schmerztherapie hinsichtlich der analgetischen Effektivität und der Beeinflussung der postoperativen Immunkompetenz verglichen. 54 Patienten erhielten bis zum Morgen des 4. postoperativen Tages entweder über einen intraoperativ gelegten epiduralen Katheter (PDK) Ropivacain und Sufentanil (PCEA-Gruppe) oder intravenös Morphin (PCIA-Gruppe). Cortisol, Leukozytenpopulationen, lymphozytäre Subpopulationen, monozytäre Oberflächenmarker und die löslichen Mediatoren TNF alpha, MCP-1, MIF, IL-8, IL-6 und IL-10 wurden perioperativ gemessen. Zudem wurde die Schmerzempfindung der Patienten in Ruhe und bei Mobilisation erhoben. Im Vergleich zur PCIA-Gruppe profitierten die Patienten der PCEA-Gruppe von einer deutlich besseren Analgesie. Cortisol wies postoperativ in beiden Studiengruppen einen ähnlich leichten Anstieg auf. Die monozytären Oberflächenmarker (HLA-DR, CD86) fielen im Verlauf deutlich ab mit einem Minimum am 1. postoperativen Tag, erholten sich bis zum 7. postoperativen Tag nahezu vollständig und zeigten keine signifikanten Gruppenunterschiede. Dagegen wurde der postoperative Abfall der CD4+ T-Lymphozyten, CD4/CD8 T-Zellratio, CD3+ Lymphozyten und CD19+ Lymphozyten bei den Patienten, die eine Epiduralanalgesie erhielten, signifikant vermindert. Hinsichtlich der löslichen Mediatoren gab es keine signifikanten Gruppenunterschiede. Somit scheint die epidurale Schmerztherapie die T-Zellkompetenz während der postoperativen Phase besser zu erhalten, während sich bei den monozytären Oberflächenmarkern und dem Stresshormon Cortisol kein Unterschied zwischen den beiden Analgesie-verfahren zeigte. / Surgeries accompanied by an extensive tissue trauma are associated with intense postsurgical pain and major perioperative homeostatic disorders. Both hyper-inflammatory and immuneparalytic reactions can be observed, what can negatively effect the postoperative course. To realise an effective and safe analgesia, epidural procedures are used to an increasing degree as an alternative method to the therapy with intravenous opioids. In this prospective, randomized, double-blinded trial we compared the patient-controlled epidural analgesia and the patient-controlled intravenous analgesia with respect to the analgesic efficiency and the influence on the postoperative immune competence. 54 patients received until the morning of the fourth postoperative day either ropivacaine plus sufentanil through an intraoperatively placed epidural catheter (PCEA-group) or intravenous morphine (PCIA-group). Cortisol, populations of leukocytes and lymphocytes, cell-surface molecules of monocytes and the soluble mediators TNF-alpha, MCP-1, MIF, IL-8, IL-6 and IL-10 were measured perioperatively. Additionally we determined the subjective pain scores of the patients in rest and with mobilisation. Patients of the PCEA-group had a better pain control compared to the patients of the PCIA-group. Cortisol showed a similar slight increase in both study-groups. The monocyte cell-surface molecules (HLA-DR, CD86) decreased in the observed period with a minimum on the first postoperative day and recovered until the seventh postoperative day without a significant difference between both groups. In contrast, the postoperative decrease in CD4+ T-lymphocytes, CD4+/CD8+ T-cell ratio, CD3+ lymphocytes and CD19+ lymphocytes was significantly reduced in patients receiving epidural analgesia. No group differences were found in soluble mediators. This implicates a better postoperative competence of T-cells induced by epidural analgesia, whereas no differences between both analgetic methods were found in cell-surface markers of monocytes and the stress hormone cortisol.

During recent decades, lumbar spinal stenosis (LSS) has become the most common indication for spine surgery, a change that coincides with a higher worldwide prevalence of overweight and obesity. Thus, surgical treatment of LSS in the overweight and obese population is common and increasing in scope. The overall aim of this thesis was to investigate whether body mass index (BMI) is related to the development of LSS, and whether BMI is linked to outcome after surgery for LSS. We further evaluated whether there are specific experiences of LSS from a patient perspective. Data were obtained for all patients registered in the Swedish Spine Register who had undergone surgery for LSS between January 1, 2006 and June 30, 2008. After adjusting for differences in baseline characteristics, patients with obesity showed both poorer results after surgery and a higher rate of dissatisfaction than patients with normal weight (odds ratio 1.73; 95% confidence interval, CI, 1.36-2.19). Furthermore, patients with obesity in the cohort reported modest weight loss at follow-up (2.0 kg; 95% CI, 1.5-2.4), and only 8% reported a clinical important weight loss 2 years after surgery. Our analysis of 389,132 construction workers, showed that overweight (incidence rate ratio, IRR 1.68; 95% CI, 1.54-1.83) and obesity (IRR 2.18; 95% CI, 1.87-2.53) were associated with an increased future risk in developing LSS when compared with patients with normal weight. To gain insight into the patients' perspective of LSS, we performed interviews with 18 patients who were on a waiting list for LSS surgery. The transcripts, analyzed with content analysis, revealed that living with LSS is a physical, mental and social challenge in which resources to cope with the condition are of major importance. In summary, obesity is associated with poorer results after surgery, and patients with obesity report modest weight loss during follow-up. In addition, obesity is associated with an increased risk to develop LSS. Our findings revealed that being a patient with LSS, naturally involves considerable suffering and pain, but it also implies being a person with his or her own resources who is able to cope with these adverse conditions.

Im Rahmen einer experimentellen Vergleichsstudie zweier bildwandlergestützter Navigationssysteme wurde die 3D-bildwandlergestützte Navigation mit der 2D-bildwandlergestützten Navigation zur Pedikelschraubenplatzierung am Modell getestet. Neben der Präzision der Bohrungen in einem postoperativen CT wurden Bildqualität, Genauigkeit des 3D-Scans, Planbarkeit und Umsetzung der Bohrungen bewertet und verglichen. Mit der 3D- Bildwandler- Navigation wurden 38 der 40 Bohrungen exakt platziert (95%). Eine Planung wurde durch einen Softwarefehler der Alpha-Version auf dem Monitor falsch wiedergegeben. Bei einer weiteren Bohrung wurde der Bohrer verkantet, wodurch Bildschirmdarstellung und Realität voneinander abwichen. Daher kam es in einem Fall zu einer lateralen Perforation der Kortikalis im Bereich des Pedikels, im anderen zu einer kaudalen Perforation. Mit der 2D- Bildwandler- Navigation konnten alle 40 Schrauben ohne Pedikelperforation platziert werden. Zwei dieser Schrauben wurden durch die ventrale Kortikalis gebohrt. Beide Verfahren überzeugten durch hohe Präzision und Zuverlässigkeit. 3 der 4 Fehlplatzierungen waren Anwender einer Software bedingt. Eine optimierte Software und verbesserte Instrumente werden diese Fehlerquote weiter reduzieren. Voraussetzung für die 2D-bildwandlergestützten Navigation sind eine gute Bildqualität sowie normale anatomische Gegebenheiten für standardisierte Projektionen. Die neue 3D-bildwandlergestützter Navigation kombiniert die Vorteile der 2D-bildwandlergestützter Navigation und der CT- basierten Navigation mit einer Verringerung der Strahlenbelastung durch den Wegfall des präoperativen CT`s und somit der Einsatzmöglichkeit im akuten Notfall sowie nach intraoperativen Repositionsmanövern. Da kein Matching erforderlich ist, wird insbesondere bei traumatischer Verletzung oder tumorbedingter Veränderung der dorsalen Wirbelstrukturen ein großer Vorteil zur CT- basierten Navigation erwartet. Aufgrund der universellen Einsatzmöglichkeiten eines Bildwandlers wird für diese neue Technologie ein breites Indikationsspektrum angenommen. / An experimental study to compare 2D- and 3D- Computer-Assisted Fluoroscopic Navigation for pedicle screw placement. Each system was evaluated by a post-operative CT and included the comparison of the palpation of the pedicular canal, the image quality and the accuracy of planning and performance. For this purpose 40 screws have been set to 9 models of lumbar spine. Using the 3D-flouroscopy based navigation 38 from 40 (95%) drillings were placed correctly. One mistake was caused by an error of the navigation-software. The second mistake was due to a drilling mistake, the drill was not shown correctly on the monitor because the drill has been canted. Using the 2D-flouroscopy based navigation all screws could be placed correctly at the pedicle, but two times the corpus has been perforated to ventral. Both techniques are precise and reliable. 3 out of 4 mistakes were caused by incorrect handling the instrument. The other mistake happened because of a software-error. If the software and the instruments will be optimised, the amount of mistakes will be reduced in the future. In case of the 2D-flouroscopy based navigation sufficient image quality, normal anatomical structures and defined projections are required. The new 3D-flouroscopy based navigation combines the benefit of 2D-flouroscopy based navigation and CT-based navigation by reducing the radiation exposure and the preoperative planning time. Therefore, this technique is suitable for use in an emergency or intraoperative repositions. Because no matching-procedure is necessary for CT-based navigation, we expect advantages especially in therapy of traumatic injuries or changes at the dorsal structures of spine caused by tumour. Furthermore, the use of fluoroscopic based navigation extends the range of applications/the spectrum of indication for this new technology.