Walter L. Bailey and Michael P. Sperl
Karol Osipowicz, Michael R. Sperling, Ashwini D. Sharan and Joseph I. Tracy
Predicting cognitive function following resective surgery remains an important clinical goal. Each MRI neuroimaging technique can potentially provide unique and distinct insight into changes that occur in the structural or functional organization of “at-risk” cognitive functions. The authors tested for the singular and combined power of 3 imaging techniques (functional MRI [fMRI], resting state fMRI, diffusion tensor imaging) to predict cognitive outcome following left (dominant) anterior temporal lobectomy for intractable epilepsy.
The authors calculated the degree of deviation from normal, determined the rate of change in this measure across the pre- and postsurgical imaging sessions, and then compared these measures for their ability to predict verbal fluency changes following surgery.
The data show that the 3 neuroimaging techniques, in a combined model, can reliably predict cognitive outcome following anterior temporal lobectomy for medically intractable temporal lobe epilepsy.
These findings suggest that these 3 imaging modalities can be used effectively, in an additive fashion, to predict functional reorganization and cognitive outcome following anterior temporal lobectomy.
Joseph T. King Jr., Michael R. Sperling, Amy C. Justice and Michael J. O'Connor
✓ Patients with medically intractable temporal lobe epilepsy are potential candidates for anterior temporal lobectomy (ATL), in which epileptogenic temporal lobe tissue is localized and surgically removed. This surgical approach can eliminate or drastically reduce seizures in the majority of patients. The authors used a decision-analysis model to examine the cost-effectiveness of a surgical evaluation and treatment protocol for medically intractable temporal lobe epilepsy. This model compared a cohort treated with the new protocol with a continuation of their immediate preoperative medical management and projected these differences over the patient's lifetime. The Markov model incorporated postoperative seizure status, patient quality of life, death from surgical and natural causes, discounting, and the direct medical costs associated with outpatient evaluation, hospitalization, surgery, antiepileptic drugs, and lifetime outpatient treatment. The intent-to-treat analysis included patients who underwent evaluation but were not eligible for ATL. Sensitivity analyses were also performed on the variables in the model.
Data from the baseline model indicated that evaluation for ATL provided an average of 1.1 additional quality-adjusted life years (QALYs) compared with continued medical management, at an additional cost of $29,800. Combining the clinical and economic outcomes yielded a cost-effectiveness ratio of $27,200 per QALY. This value is comparable to other accepted medical or surgical interventions, such as total knee arthroplasty ($16,700/QALY) or coronary artery balloon angioplasty ($40,800/QALY). Sensitivity analyses demonstrate that the results are critically dependent on postoperative seizure status and improvement in quality of life. Although further work is necessary to quantify the improvement in quality of life after epilepsy surgery better, the present data indicate that ATL for treatment of intractable temporal lobe epilepsy is a cost-effective use of medical resources.