You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["HealthCareActivity", "InjuryOrPoisoning", "BodySubstance", "IntellectualProduct", "AnatomicalStructure", "SpatialConcept", "Chemical", "Bacterium", "MedicalDevice", "Organization", "BiomedicalOccupationOrDiscipline", "Finding", "BiologicFunction", "Virus", "ResearchActivity", "ClinicalAttribute", "PopulationGroup", "Eukaryote", "BodySystem", "Food", "ProfessionalOrOccupationalGroup"].

Please return the output as a JSON object of the format: {"Virus": ["HIV", ...], "Bacterium": ["MRSA", ...], "AnatomicalStructure": ["Lung", ...], "BodySystem": ["CNS", ...], "BodySubstance": ["Serum", ...], "Finding": ["Headache", ...], "InjuryOrPoisoning": ["Fracture", ...], "BiologicFunction": ["Death", ...], "HealthCareActivity": ["Biopsy", ...], "ResearchActivity": ["Clinical trial", ...], "MedicalDevice": ["Lenses", ...], "SpatialConcept": ["Camps", ...], "BiomedicalOccupationOrDiscipline": ["Forensic medicine", ...], "Organization": ["WHO", ...], "ProfessionalOrOccupationalGroup": ["Provider", ...], "PopulationGroup": ["Swimmers", ...], "Chemical": ["Gold", ...], "Food": ["Rice", ...], "IntellectualProduct": ["RPAM", ...], "ClinicalAttribute": ["Biomarker", ...], "Eukaryote": ["Dogs", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Decompression Surgery Alone Versus Decompression Plus Fusion in Symptomatic Lumbar Spinal Stenosis: A Swiss Prospective Multi-center Cohort Study with 3 Years of Follow-up Retrospective analysis of a prospective, multicenter cohort study. To estimate the added effect of surgical fusion as compared to decompression surgery alone in symptomatic lumbar spinal stenosis patients with spondylolisthesis. The optimal surgical management of lumbar spinal stenosis patients with spondylolisthesis remains controversial. Patients of the LSOS with confirmed DLSS and spondylolisthesis were enrolled in this study. The outcomes of this study were Spinal Stenosis Measure (SSM) symptoms (score range 1-5, best-worst) and function (1-4) over time, measured at baseline, 6, 12, 24 and 36 months follow-up. In order to quantify the effect of fusion surgery as compared to decompression alone and number of decompressed levels, we used mixed effects models and accounted for the repeated observations in main outcomes (SSM symptoms and SSM function) over time. In addition to individual patients ' random effects, we also fitted random slopes for follow-up time points and compared these two approaches with Akaike's Information Criterion (AIC) and the chi-squared test. Confounders were adjusted with fixed effects for age, gender, BMI, diabetes, CIRS musculoskeletal disorders and duration of symptoms. One hundred and thirty-one patients undergoing decompression surgery alone (n = 85) or decompression plus fusion surgery (n = 46) were included in this study. In the multiple mixed effects model the adjusted effect of fusion versus decompression alone surgery on SSM symptoms was 0.06 (95% confidence interval, CI: -0.16 to 0.27) and -0.07 (95% CI: -0.25 to 0.10) on SSM function, respectively. Among the patients with degenerative lumbar spinal stenosis and spondylolisthesis our study confirms that in the two groups, decompression alone and decompression plus fusion, patients distinctively benefited from surgical treatment. When adjusted for confounders, fusion surgery was not associated with a more favorable outcome in both SSM scores as compared to decompression alone surgery. 3.
{"AnatomicalStructure": ["Spinal Stenosis"], "Bacterium": [], "BiologicFunction": ["degenerative lumbar spinal stenosis", "DLSS", "spondylolisthesis", "Lumbar Spinal Stenosis", "musculoskeletal disorders", "lumbar spinal stenosis", "diabetes"], "BiomedicalOccupationOrDiscipline": [], "BodySubstance": [], "BodySystem": [], "Chemical": ["duration"], "ClinicalAttribute": ["BMI"], "Eukaryote": [], "Finding": ["symptoms", "number of decompressed levels", "follow-up"], "Food": [], "HealthCareActivity": ["fusion", "decompression surgery", "Decompression", "decompression", "optimal surgical management", "fusion surgery", "Decompression Surgery", "decompression alone surgery", "Fusion", "surgical fusion", "surgical treatment"], "InjuryOrPoisoning": [], "IntellectualProduct": ["AIC", "chi-squared test", "Akaike\u0027s Information Criterion"], "MedicalDevice": [], "Organization": [], "PopulationGroup": ["Swiss"], "ProfessionalOrOccupationalGroup": [], "ResearchActivity": ["outcomes", "Retrospective analysis", "repeated observations", "Prospective Multi-center Cohort Study", "follow-up", "Follow-up", "prospective, multicenter cohort study", "outcome", "LSOS"], "SpatialConcept": [], "Virus": []}