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Facial pain is often debilitating and can be characterized by a sharp, stabbing, burning, aching, and dysesthetic sensation. Specifically, trigeminal neuropathic pain (TNP), anesthesia dolorosa, and persistent idiopathic facial pain (PIFP) are difficult diseases to treat, can be quite debilitating and an effective, enduring treatment remains elusive. We retrospectively reviewed our early experience with stimulation involving the trigeminal and sphenopalatine ganglion stimulation for TNP, anesthesia dolorosa, and PIFP between 2010–2014 to assess the feasibility of implanting at these ganglionic sites. Seven patients received either trigeminal and/or sphenopalatine ganglion stimulation with or without peripheral nerve stimulation, having failed multiple alternative modalities of treatment. The treatments were tailored on the physical location of pain to ensure regional coverage with the stimulation. Fluoroscopy or frameless stereotaxy was utilized to place the sphenopalatine and/or trigeminal ganglion stimulator. All patients were initially trialed before implantation. Trial leads implanted in the pterygopalatine fossa near the sphenopalatine ganglion were implanted via transpterygoid (lateral-medial, infrazygomatic) approach. Trial leads were implanted in the trigeminal ganglion via percutaneous Hartel approach, all of which resulted in masseter contraction. Patients who developed clinically significant pain improvement underwent implantation. The trigeminal ganglion stimulation permanent implants involved placing a grid electrode over Meckel’s cave via subtemporal craniotomy, which offered a greater ability to stimulate subdivisions of the trigeminal nerve, without muscular (V3) side effects. Two of the seven overall patients did not respond well to the trial and were not implanted. Five patients reported pain relief with up to 24-month follow-up. Several of the sphenopalatine ganglion stimulation patients had pain relief without any paresthesias. There were no electrode migrations or post-surgical complications. Refractory facial pain may respond positively to ganglionic forms of stimulation. It appears safe and durable to implant electrodes in the pterygopalatine fossa via a lateral transpterygoid approach. Also, implantation of an electrode grid overlying Meckel’s cave appears to be a feasible alternative to the Hartel approach. Further investigation is needed to evaluate the usefulness of these approaches for various facial pain conditions.

The safe and reversible nature of deep brain stimulation (DBS) has allowed movement disorder neurosurgery to become commonplace throughout the world. Fundamental understanding of individual patient's anatomy is critical for optimizing the effects and side effects of DBS surgery. Three patients undergoing stereotactic surgery for movement disorders, at the institution's intraoperative magnetic resonance imaging operating suite, were studied with fiber tractography. Stereotactic targets and fiber tractography were determined on preoperative magnetic resonance imagings using the Schaltenbrand-Wahren atlas for definition in the BrainLab iPlan software (BrainLAB Inc., Feldkirchen, Germany). Subthalamic nucleus, globus pallidus interna, and ventral intermediate nucleus targets were studied. Diffusion tensor imaging parameters used ranged from 2 to 8 mm for volume of interest in the x/y/z planes, fiber length was kept constant at 30 mm, and fractional anisotropy threshold varied from 0.20 to 0.45. Diffusion tensor imaging tractography allowed reliable and reproducible visualization and correlation between frontal eye field, premotor, primary motor, and primary sensory cortices via corticospinal tracts and corticopontocerebellar tracts. There is an apparent increase in the number of cortical regions targeted by the fiber tracts as the region of interest is enlarged. This represents a possible mechanism of the increased effects and side effects observed with higher stimulation voltages. Currently available diffusion tensor imaging techniques allow potential methods to characterize the effects and side effects of DBS. This technology has the potential of being a powerful tool to optimize DBS neurosurgery.

Introduction The subthalamic nucleus (STN) and the globus pallidus internus (GPi) are the most common surgical targets for the treatment of Parkinson’s disease. We studied directionally colored fractional anisotropy (FA) and diffusion tensor imaging (DTI) sequences to better target these anatomical regions. Methods Four patients undergoing stereotactic surgery for movement disorders were studied. Stereotactic targets and fiber tractography were determined on MRIs using the Schaltenbrand–Wahren atlas for definition in the iPlan software. In addition, post-operative imaging was fused to preoperative FA sequences for end-result identification. Axial, sagittal, and coronal images of the FA sequence were studied. DTI parameters used ranged from 2 to 4 mm for voxel size in the x/y/z planes, fiber length was kept constant at 15 mm and FA threshold of 0.25. Results Colored FA maps resulted in a key signature in and around the STN and GPi. Regions identified include, but were not limited to: the internal capsule, nigral projections, the thalamic fasciculus, Forel’s fields H1 and H2, zona incerta, suthalamic fasciculus, tegmental tracts, and cerebello-rubro-thalamic tract. Conclusions Colored FA maps allow a potential method to identify the STN and GPi accurately. DTI has proven to be a powerful tool that can be used to augment identification of the STN nucleus and GPi used for stereotactic surgery.