An experimental animal model for percutaneous procedures used in trigeminal neuralgia

This study describes an experimental rabbit model that allows the reproduction of percutaneous operations that are used in patients with trigeminal neuralgia (TN). Attention was given to an exact anatomical description of the rabbit's middle cranial fossa as well as the establishment of conditions for a successful procedure.

Morphometric measurements were taken from 20 rabbit skulls and CT scans. The anatomy of the trigeminal nerve, as well as its surrounding structures, was assessed by bilateral dissection of 13 New Zealand white rabbits (NWR). An ideal approach of placing a needle through the foramen ovale to reach the TG was sought. Validation of correct placement was realized by fluoroscopy and confirmed by dissection.

Precise instructions for successful reproduction of percutaneous procedures in NWR were described. According to morphological measurements, for balloon compression of the trigeminal ganglion (TG) the maximal diameter of an introducing cannula is 1.85 mm. The diameter of an empty balloon catheter should not exceed 1.19 mm, and the length of the inflatable part of the balloon can range up to 4 mm. For thermocoagulation the needle electrodes must not exceed an external diameter of 1.39, mm and the length of the non-insolated tip can range up to 4 mm. Glycerol rhizolysis can be achieved because the trigeminal cistern in the NWR is a closed space that allows a long dwelling time (>10 min) of the contrast agent.

An experimental NWR model intended for the reproduction of percutaneous procedures on the TG has been meticulously described. This provides a tool that enables further standardized animal research in the field of surgical treatment of TN.