(P13) Treatment of the Ventral Intermediate Nucleus for Medically Refractory Tremor: A Cost-Analysis of Stereotactic Radiosurgery Versus Deep Brain Stimulation

Abstract

The treatment of medically refractory tremor has evolved over the past half-century from intraoperative thalamotomy to deep brain stimulation (DBS) of the thalamic ventral intermediate nucleus (VIM). VIM DBS has proven efficacious for patients with essential tremor (ET), tremor-dominant Parkinson’s disease (PD), and less common causes of tremor including multiple sclerosis and orthostatic tremor. Within the past 15 years, unilateral radiosurgical VIM thalamotomy has emerged as a comparably efficacious treatment modality, particularly for ET and tremor-dominant PD patients. Despite extensive investigation of these treatment modalities, there has been no cost-comparison of unilateral DBS versus radiosurgery of the VIM. An extensive literature search of VIM DBS series dating back to the seminal manuscript (Benabid et al., Lancet 1991) was performed to ascertain an estimated operative time for the procedure. The total cost of VIM DBS, comprised from the separate costs of the operating room, anesthesia, and neurosurgeon was then calculated from this operative time based on hospitals geographically representative of the entire United States using current procedural terminology (CPT) and work relative value unit (RVU) codes. The 2016 Medicare Ambulatory Payment Classification (APC) for stereotactic radiosurgery (SRS) was added to the work RVU to determine the total cost of VIM SRS for both Gamma Knife and linear accelerator SRS. Cost estimates assumed that VIM DBS was performed without intraoperative microelectrode recording. The mean operative time of unilateral VIM DBS was 146.4 minutes, yielding a mean operating room cost of $14,726.38, anesthesia cost of $2,420.25 and neurosurgeon cost of $785.78 for a total unilateral VIM DBS cost of $17,932.41 per patient. For SRS VIM, the APC was $8,827, and was added to the neurosurgeon cost of $613.90 for Gamma Knife ($528.53 for linear accelerator) and radiation oncology cost of $1370.87 to yield a total radiosurgery cost of $10,811.77 ($10,726.40 for linear accelerator). The Gamma Knife and linear accelerator costs were 40% less expensive than unilateral VIM DBS. Radiosurgery of the VIM is 40% less expensive than unilateral VIM DBS in treatment of medically refractory tremor, regardless of radiosurgical modality. This finding provides another important aspect to be considered for treatment modality decision-making, and argues for increased involvement of radiation oncologists in concert with movement disorder neurologists and functional neurosurgeons in the management of medically refractory tremor patients, particularly those who may not be able to medically or financially tolerate the stresses of operative intervention.