The structure of the model is consistent with the theory behind spinal stenosis. A decision tree model was chosen to demonstrate the pathways that the treatments follow referred to impacts and complications of the interventions, whereas the disease pathways are not reflected.
In order to construct the decision tree model different sources were adopted. Nevertheless some of the references used were not accessible to the public such as the Vertos Data Set, reference 28.
Assumptions were another essential element adopted to construct the model. The assumptions made the model simpler missing the objective, perspective and scope of the model. The assumptions considered the failure of mild treatment and surgery if there was no symptoms relief or if them recurred in two years after the interventions. Furthermore, no further treatment was considered for ESI patients due to the population of study are patients who failed the conservative therapy (Udeh et al, 2014).
Even though the assumptions helped the construction of the decision tree model, the model does not fulfil the decision problem stated and the causal relationships within the model. According to Philips et al (2004:8) “The absence of data is not itself a justification for simplification.”
A Markov model is more accurate for several reasons. Firstly, a Markov model provides a better way to represent clinical complications with continuous risk. LSS is a chronic disease that can last a lifetime. Furthermore, conservative treatment has to be applied several times due to its effect is limited while laminectomy present different complications (Udeh et al, 2014).
Secondly, this model allows us to know when events occur as well as the utilities of each one, which helps to measur...
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...portance the validity of them through the Philips et al (2004 and 2006) guideline help to decide if the outcome of a developed model should be considered.
In the case of the study of Udeh et al (2014) we can point out that the model has different flaws in structure, data and validity when contrasting it with the good practice guideline. Even though the weaknesses of the model, it is important to mention that mild procedure is an innovative treatment that should be considered to treat LSS for patients who have failed conservative treatment and are not candidates for surgery.
As the authors mentioned, it is necessary to rerun this model with a longer time horizon and follow-up (Udeh et al, 2014) to confirm the outcomes obtained. Furthermore, it is necessary to take into consideration all the flaws mentioned throughout this appraisal to make the study more reliable.