A 33-year-old female patient, a mother of one child, developed a left upper limb dystonia after being asphyxiated under blankets at the age of 4 weeks. The dystonia in both lower limbs progressively developed into a generalized form, accompanied by a left facial spasm. She had undergone orthopedic surgery because of right ankle eversion and lateral deviation of the right great toe 2 years ago. The most painful symptom to her was a dystonia of left upper limb accompanied by tremor occurred in both resting and exercise. The symptoms were not improved by medical treatment including nortriptyline, levodopa, clonazepam, baclofen, and biperiden. There was no family history of movement disorders. The patient was referred to our institution for evaluation of the DBS (November 14, 2006).

She had alert consciousness and normal intellectual ability. Motor power grades were V in all extremities, and sensory was also intact. After orthopedic surgery, the right ankle was nearly corrected but the right great toe was still deviated laterally. Her gait was mildly ataxic. The left arm was adducted in the shoulder and extended in the elbow. The left wrist was hyperextended, with continuing rhythmic clenching and opening of the fist (Fig. 1A). The dystonia severity was measured using Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS); her preoperative movement score was 33 points, and functional disability score was 10 points. Mini-mental state examination (MMSE) was 29 points, and Beck’s depression inventory (BDI) scale was 3 points. DYT-1 gene was not detected. On magnetic resonance imaging (MRI), there were no definite focal lesions in the brain parenchyma.

In November 2006, she underwent bilateral GPi implantation. A Leksell stereotactic frame was secured to the patient’s head after application of a local anesthetic and she was transferred to the MR suite. The posteroventral portion of the GPi was targeted by means of axial, sagittal, and coronal MRI images (5). The pallidal target was 12.4 mm anterior to the midcommisural point, 20 mm lateral to the midline, and 3 mm below the intercommisural line in both side. The procedure was performed under general anesthesia, with the assistance of microelectrode recording (MER). A set of four microelectrodes (Differential microTargeting® Electrodes; FHC, Chemnitz, Germany; 1.5 MΩ impedance) were sequentially inserted toward the anatomical target within the GPi, which was vertically on the axial slice at the level of anterior commissure and horizontally at the junction between the two posterior quarters of the GPi (6). Permanent DBS electrodes (DBS 3387; Medtronic, Minneapolis, MN, USA) placements were determined without interpreting vessels, ventricles, and sulci. The electrode of the left side was inserted earlier than that of the right side, to minimize the error of the dominant side by brain shifting after cerebrospinal leakage. The electrodes were fixed to the burr hole and connected to pulse generators (IPG, Soletra 7426; Medtronic) implanted on both subclavicular pouch. There were no adverse events. One day after surgery, stimulation was begun using an N’vision programmer (Medtronic). The initial setting was as follows: monopolar stimulation by using Contact 1 as the negative and the internal pulse generator case as the positive pole with an amplitude of 3.72 V, pulse width 60 μsec, and frequency 130 Hz. Six months later, we performed a repeat computed tomography (CT) scan and fused it to the preoperative MRI to confirm the locations of the leads (Fig. 2).

The movement and disability scores and the stimulation parameters were recorded, as described in Tables 1 and 2. After DBS implantation, considerable improvement was noted. Three months later, she showed improvement in dystonic dyskinesia, but facial dyskinesia on left eyelid was still noted. Subjectively, she handled the cleaning supplies more easily. Her movement score was decreased to 29 points and disability score to 5 points, but Karnofsky performance scale (KPS) score was still checked as 80 points at 6-month follow-up. The stimulation parameters were adjusted based on the patient’s symptom. The left-sided dystonic posture and walking had kept improving (Fig. 1B). She found it easier to clean, but still had difficulty in washing. At 12-month follow-up, the movement score decreased to 28 points (improvement rates, 15%) and disability score to 5 points (improvement rates, 50%) were checked, and she had sustained such improved state. She could do housework including cleaning and doing the laundry without difficulty. Four years later, the obstetricians consulted us about her 38 weeks pregnancy state. The maternal serum triple test and amniocentesis were performed because of her old age, and revealed low risk of congenital anomaly. A scheduled caesarian section was carried out under general anesthesia. After induction using thiopental and succinylcholine, intubation was done quickly, followed by DBS turn off. The surgery lasted for one hour, and the blood pressure was maintained within the normal range during the surgery. For hemostasis, only bipolar electrocautery was used. Before awakening from the anesthesia, DBS was turned on as the same parameters previously adjusted. After delivery, she could feed her baby by herself, because the dystonia of left upper extremity and hand was improved. Six years after DBS surgery, her general condition was more improved, and she started to play ping-pong and billiards. Until now, she has been showing continual improvement and being good at housework, carrying for children, with no trouble in daily life based on her KPS score of 90 points and MMSE score of 30 points. She even obtained a driver’s license in April 2014 and now drives a car by herself.