Properties and Storage Methods of the Stratathane ST-504-Based Neurosurgical Tumor Model: Comprehensive Analysis

Constrains on neurosurgical residents' work hours demand innovative teaching models to complement the traditional "in the operating room" model. Stratathane ST-504 (Strata-Tech, Inc., Des Moines, Iowa, USA) has been proposed as a useful artificial neurosurgical tumor model. The consistency, dissectability, and radio-opacity of this model strongly depend on its preparation and storage. However, little work has addressed the interplay of these properties. Hence our study was undertaken to explore the properties of ST-504, its preparation, and storage and how these interactions affect its radio-opacity and consistency.

Tumor mixture was prepared by mixing 4.5 mL of water, 1.5 mL of computed tomography contrast medium, 2 mL of ST-504, and 0.5 mg turmeric powder. The tumor mixture was either allowed to solidify, yielding solid tumor blocks, or injected into an anatomic specimen to create a tumor model. Both tumor blocks and tumor model were stored at different temperature, under different storage conditions and for different time. Their volumes, computed tomography appearance, and consistency were evaluated.

The tumor blocks stored in water or ethanol absorbed fluid, resulting in enlargement and associated decrease in radiodensity and consistency. The same results were displayed by the tumor implanted in cadaveric specimen.

For any given ratio of ST-504/water, the time sequence after polymer solidification and the storage method determine the computed tomography appearance and consistency of the tumor block/model. When taking these properties into consideration, ST-504-based artificial tumor models can be customized for different dissection practices, from more solid (meningioma-like) to less solid (schwannoma-like) models.