A 56-year-old male with history of congenital external auditory canal atresia status post multiple reconstructive surgeries presented with severe, burning facial pain in his left cheek and jaw. The pain radiated to his left ear and was associated with intermittent swelling. On examination, the patient demonstrated decreased sensation on the left face in divisions V1–V3, allodynia, and a slight left facial droop. He had previously been diagnosed with trigeminal neuralgia, failing extensive medical management due to poor relief and lack of medication tolerance, which included carbamazepine, gabapentin, antidepressants, and baclofen. He also tried multiple migraine medications and botox to rule out migraines. Six months after failing a trigeminal nerve block, he underwent microvascular decompression at another facility with mild improvement of his facial pain. Postoperatively, he suffered a stroke, resulting in both mild weakness and complex regional pain syndrome involving the left side of his body, including worsening of his facial pain. His pain was unresponsive to non-steroidal anti-inflammatory drugs, steroid injections, multiple antiepileptics, and intravenous opioids and on average rated his pain as 10/10 in severity via the visual analog scale (VAS). He was diagnosed with complex facial pain syndrome. After failure of both peripheral nerve stimulation and transcranial magnetic stimulation, motor cortical stimulation was offered as an off-label therapy for refractory CFPS.
Preoperatively, fMRI and DTI (General Electric Company, Discovery™ MR750w GEM 3.0T, manufactured by General Electric Company, USA; NordicNeuroLab Advanced fMRI Solution, manufactured by NordicNeuroLab Inc., Norway) were used to identify regions within the motor cortex corresponding to tongue and hand regions. The patient was positioned in the supine position, and neuronavigation (Synaptive BrightMatter Guide (V 1.5.4) and Modus Plan (V 2.0.1), manufactured by Synaptive Medical, Canada) was utilized to delineate the hand, face, and tongue regions of the motor cortex using preoperative imaging, shown in Fig. 1. A curvilinear incision was made on the left side of the scalp which incorporated prior incisions. A bone flap was turned and the dura exposed. Phase reversal using a 6-electrode array was used to identify corticospinal tracts, and a stimulus probe confirmed the location of the motor areas of the hands and face (Cadwell Cascade Pro IONM, manufactured by Cadwell Industries Inc., USA). Once identified, two Abbot paddle spinal cord stimulation electrodes (Abbott Lamitrode 44, Paddle Lead Kit 3244, manufactured by Abbott Laboratories, USA) were placed on the dura over regions corresponding to the motor cortex on fMRI, DTI and cortical mapping (Fig. 2). The skull flap was replaced, and the incision was closed. Postoperative head computed tomography (CT) (General Electric Company, Discovery CT750 HD, manufactured by General Electric Company, USA) was overlaid with the preoperative fMRI, which demonstrated excellent electrode placement (Fig. 3). His postoperative exam was similar to his preoperative baseline. He was initially programmed at a continuous frequency of 50 Hz, pulse width of 250 μs at 0.5–11 mA. Upon discharge, the patient reported significant reduction in dysesthesias and allodynia. Two months postoperatively, he complained of worsening pain. Stimulator adjustments were made for alternate programming, which allowed him to increase his continuous dose and pulse width to 60 Hz and 400 μs, respectively, or switch to an intermittent dose of 40 Hz at an intraburst rate of 500 Hz with a pulse width of 1000 μs and maximum current of 1 mA. The patient had some fluctuation of his symptoms with sporadic severe pain attacks which brought him to the emergency department, however, the number of these visits decreased by over 50% compared to his presentation preoperatively. Overall, at 6 months postoperatively, the patient rated his pain on average as 4/10 via VAS, a 60% decrease in severity from his initial presentation.